April Amy Dala by MikeJenny


									                                         Unit 3 Notes
April 8, 2009
      For final:
           o Expect case study questions
                   Matching injury to effects and the other way around
           o Will cover learning and memory, sleep, fear, love
           o Only the first half of the last third of class will be pedantic (circuitry, etc.)
      Video Examples
           o McGurk (sp?) effect
                   How much you synthesize information by combining what you see and what you
                            Done in the association cortices
                            How much you think based on all the sensory input that’s coming.
                            See hand out—top side is info coming in. Bottom side is info going out
           o Ex with tongue
                   The sensation of your tongue between the trailing R, and trailing L is completely
                   You reference what you say based on what you see
           o Ex. With person with injury in Broca’s Area
                   Able to think what he wants to say, but unable to form the words
                   Can respond quickly when asked about something intuitive
                   Lost connection from frontal lobe to auditory cortex
                   Only on the left side of his brain
                   He can write well, b/c it is a diff part of the brain
           o Now understand that we’re born with gibberish
                   All of the intonations exist in our brains as babies
                   Parents can play gibberish from babies all over the world, and they will be able
                      to encourage the ability to speak many languages
                   We develop an intrinsic response—it is a diff pathway in your brain
                   No—is a universal refusal.
           o Ex. With Wernicke’s Injury
                   Man talks constantly.
                   Man is making complete sentences (could write it out), but his hand motions
                      don’t make sense
                            Hand motions go based on what he hears
                            Brain is forming speech, but he can’t hear himself speak
                            He hears—and if you sing to him, he understands
                   Part of speech formation is that you check what you say with what you hear
                   When asked where he lives, he echoes back the phrase
                 When asked how long he’s been a dentist—develops into a math problem
                 Think that wernike’s area is actually less than 80K neurons
        o Ex. With Boy who echo-locates
                 Clicks his tongue, and can then sense the world around him using echo-location
                 Can ride bike/define objects
                 Range over 20 feet
                 Can tell whether object is flat/round by nature of sound
   Motor targets
        o Muscles
        o Vast majority of the final is the first two exams
        o Info from the CNS to the PNS
                 Diff incoming sensory pathways
        o Two major pathways—green is all stuff that deals w/ memory
                 Limbic system
        o Motor cortex on the other side of the central sulcus
                 All the sensations influence via association cortices in order for you to control
                    the motor cortex
   Information coming in through pathways
        o Much info from the thalamus and medulla goes to the cerebellum (‘little brain’)
                 Then sends stuff to the motor cortex
                 Premotor cortex, primary motor cortex and a motor loop
                          Motor loop: basal ganglia, thalamus and back to cerebellum
                          Controls reflexes- like knee jerk reaction
                 Finally, info goes back to the medulla, down through one last processing center
                    in the spinal cord and then your motor response
        o Virtually all your behavior goes through that pathway, includes going to sleep and being
            attracted to someone
   Remainder of the course:
        o Cerebellum to basal ganglia to limbic system
        o The limbic system is our last target includes:
                 Amygdale: all about fear
                 Hippocampus: memory
                 Hypothalamus: link to how all of this drives your endocrine system
   Have basal ganglia and cerebellum
        o Talk to the upper motor systems
        o Basal ganglia are the things that are affected by parkinson’s—deals w/ the motor cortex
        o The cerebellum bypasses that and goes to the brainstem
        o Lower motor neurons go from the spine to their targets
        o Upper motor systems descending from the brain and cerebellum
   Refelexes
        o Visual and auditory information that goes through the spine
   Cerebellum talks to the brainstem, short circuits the bigger loop of the basal ganglia
   Descending pathway comes from the primary motor cortex
        o Primary information comes down the brainstem
        o Major shift called the pyramidal decussation
        o Lateral cortical spinal tract
        o Descends and goes to targets—ipsilaterally
        o There is another secondary pathway—cortico reticulo spinal pathway
                 As you go through the reticular formation—information is split and it goes to
                     both sides
                 Ex. With reaching for something—move both of your hands
                          Other arm goes back
   Other pathways:
        o Collicular spinal tract
                 Reflex
                 Superior colliculus, reflex arc in the cervical spinal cord.
                 Just below the medulla
        o Rubro spinal tract
                 Deals w/ the cerebellum
   Vestibulo spinal tract
        o Has lateral, medial vestibular nuclei
        o Has to do w/ reflexes
   Reticulo tract—is in the pontine
        o Has to do w/ control
   Vestibular reflex tract
        o 8th cranial nerve that comes out and has many targets
                 Thalamus, extra ocular motor neuron, kneck and limb motor neurons
                 This is the vest. System going through the vestibular nucleus, and it’s controlling
                     your arms and posture, etc
                 Also controls your eyes
                          V-o-r reflex
                          Keeps your eyes focused on something even while head is moving
                          Leopard running across field—no matter which way head is moving,
                             have eyes fixed on target
                          Automatically- through a motor system
                                o Head turns to left- eyes turn to right
                                o Vest. System senses rotation which sends signal to vest. Nucleus
                                o This sends excitatory signal that fires lens, and sends an
                                     inhibitory signal that relaxes the other muscle
                                          Same way we’ve seen—using glu and opposition
                                o Also happens on the other side. See slide
                                o Another example of lateral inhibition
   Somatic motor system
       o 3 types of muscles
               Skeletal
               Smooth
               Cardiac
       o Smooth: guts, stomach diaphragm, around bloodstream, mucles in blood vessels
       o All muscles are innervated
               Either by voluntary or autonomic motor system
       o Ach is the prime source of skeletal muscles, and has a completely diff effect on smooth
           and cardiac mucles
       o Making distinction between nt’s and their receptors on the three diff muscular systems
   Muscles
       o See slide
       o Ex of radial muscles on forearm
       o Muscle made up of bundle muscle fibers
               Each muscle fiber made up of mult. Cells
               Inside of each fiber is myofibril
               Smallest muscle segment is a sarcomere
               Every muscle fiber is innervated with motor neurons
                        That motor neuron causes the whole fiber to contract
                        All of the myofibrils contract with it
       o What makes a muscle strong not necessarily the size
               Obviously more actual muscle fibers
               Control of the reflexes
                        Literally the lack of control to fight the reflex that inhibits the muscles
                          that prevents you from the strength you really want to have
       o Wrapped around each myofibril is the sarcosplasmic reticulum
               Same thing as the endoplasmic reticulum
               Diff in muscles than other tissues
               In addition. Laying next to it is an invagination of the sarcoplasmic membrane
                        That membrane has tubes that go in—extensions of the membrane
                        So, the depolarization of the motor neuron travels deep into the muscle
                          fiber using those tubes
                        See slide
       o Ach is released at the synaptic terminal.
               Depolarize using ach receptors
               This depolarization has an effect all the way down the t tubule
               These arrows just represent the depolarization
                        This depol of the t-tubule affects the sarcosplasmic reticulum
                        This releases ca, which comes in through the center of the sarcomere
                          and causes a change in muscle length
           o   A band, I band z line—see slides
                    When you have a muscle fiber—can distinguish these things in pics
                    Z- line is the attachment point from one sarcomere to the next
                    A band and I band are visual cues as to where the proteins are
           o   Collections of myosin that are laying alongside actin fibers
                    One sarcomere—with ca they slide together
                    Slide together only a very small distance
                    All of the movement of the muscle is just all of the sarcomeres moving together
                    Sliding is done as a result of the action of myosin
                            It flexes and changes conformation and pulls the actin fibers together
                    Movie of actin and myosin

April 10, 2009
      Association Cortices
           o Finished vision, and got to the mt
                    The mt was capable of putting together approx. 26 to 28 frames/sec
                    Able then to determine that there had been some motion
      Many other aspects of vision that we deal w/
           o Attention
                    Different aspects of attention
                             Change blindness
                                   o Ex. From Harvard experiment. Two men that don’t look alike
                                       trade off and ppl don’t notice.
                                   o You’re constantly editing out what’s around you, and only
                                       paying attention if you absolutely have to
                                   o Change Blindness—75% of the time you only remember for
                                       about 3 seconds what you were looking at. Then you
                                       immediately look away, and you don’t see it.
                                   o Large group of ppl who are capable of storing info for long
                                       periods of time based on what they are actually seeing. These
                                       ppl can only recall change if you mention it to them.
                                   o This is a cue to how our brain works
                                   o See that a person is there, but it is possible that when you take
                                       that person in, you store the general physique—not actually
                                       seeing the appearance each time.
                             Room ex. With two girls
                                   o See one girl coming up from the corner, and she appears to be
                                       growing bigger. We have the image of a room stored better
                                       than the image of the two girls.
                                   o Willing to distort the girls, not willing to distort the room
                  Neglect
                      o Has to do w/ region in parietal lobe
                      o This region is the thing that says pay attention to the whole field
                      o Person is given something to draw, and they draw what looks
                           like a whole house to them.
                                 The person only draws in part of the house
                                 She’s neglecting the left hand field of view
                                 If given a piece of paper with a lot of lines and told to
                                   draw crosses through them all, will only do the right
                                   hand side, and their brain fills in the left hand side
                      o Has to do w/ the fact that you are having to pay attention to the
                           whole thing
                      o You manufacture a lot of what you see
                      o Neglect is a part of the brain
                      o If someone is looking at the left field, the right part of the brain
                           is managing most of that including the right field
                                 Whereas, if you are only looking at the right field, there
                                   is a very small part, which is not operating very well
                                   which is in the left hemisphere
                      o Most of your attention is ruled in a neglect center
                                 Contralateral neglect: where the right side is damaged.
                                 Video of woman drawing pic
                      o If you remove this ability, you have very little attention and you
                           are basically filling in the rest w/ your brain
o   Recognition
        Face recognition and object recognition
        Speech on the left side of the brain
        Face recog is on the right hand side
        Fusiform face cortex which is on the inside of the temporal lobe
                 Temporal lobe is also part of the pathway responsible for finding the
                   words of things you want to talk about
                 3 types of faces
                        o Familiar with that you care about
                        o Faces that other ppl care about—famous ppl
                        o Faces that you’re asked to memorize
                                Ppl who have damage to this area and can’t recognize
                                   any of these categories
                                Won’t even recognize themselves
                                        Just see the features, don’t put it together as an
                                           object which is a face
        If inability to name objects—can still name faces
                          It’s a connection between the language part of the brain, and the visual
                           cortex—called the IT pathway
                          If you cut the corpus callosum you prevent the left side from talking to
                           the right
                                o If you were to close your right eye and look that info from the
                                    left field of view is only going to the right side
                                o So, you can recognize the face, but you have to get the name
                                    from the other side
                                o Cut the corpus collosum it separates from knowing the name
                          IT pathway is between language and what you visually see
                                o Naming objects
   Executive Function
       o Part of the prefrontal cortex
       o On the front, have a planning and judgement area—executive function
       o Basically a part of the brain that we considered the most advanced
                 Alcohol attacks this area almost immediately
       o Phineas gage
                 Working on a railroad and a spike went through his eye
                 Took out his eye and also a very small region that connects the prefrontal cortex
                    to the rest of the brain
                 Separated the frontal lobe from the rest of the brain
                 Went from being one of the most beloved bosses to being a jerk
                         Lost the sensation of whether he should say that
       o Lobotomy
                 Won a nobel prize
                 Take ppl who would make bad decisions to make nicer, like promiscuous
                 Texas was the last group of ppl to perform one in 1967
                 Long shafts with knives that they stick into your brain
                 Makes ppl completely docile
                 Rose Kennedy had this performed
                 Makes ppl vegetables
                 Mentality of a four or five year old
                 Eliminates any kind of drive
   Muscles
       o Skeletal, smooth, cardiac
       o Broken down into fibers which are in bundles
                 Each fiber has a myofibril in it, which is just a whole string of sarcomeres
                 Two primary proteins are actin and myosin
                 Secondary structure: sarcosplasmic reticulum
                  extensive network of calcium stores
                  if a motor neuron and hit its target, which would be an individual muscle fiber,
                   which has many myofibrils in it
                         caused a depolarization in membrane, which travels down T-tubules
                           (just an extension of the membrane)
                         causes a release from the sarcosplasmic reticulum of Ca
                         two major steps we’re interested in
                                o what’s happening between the T tubule and the s.r
                                o what ca is doing to the bundles
   Myosin has two states
       o One is when it is bound to the actin which causes a contraction
       o Other is when it is unbound and head is cocked backwards
       o In order to release, must bind ATP
       o In order to bind, just need to have the site available
                Ca is what makes the site available
       o Troponin is the protein that covers the actin, which has a binding site for the myosin
                The ca binds to the troponin, which moves out of the way and exposes the site
                The myosin head then binds
                When the myosin head binds, ATP is cleaved
                Then the head can retract
                Can’t come off until ATP binds again
                The head contracts backwards the moment it binds
                ATP binding that causes the head to come off, and it’s ATP splitting that causes
                   the head to retract
       o Need ATP to separate the two
                It’s the hydrolysis of ATP that cocks the head backwards
                Myosin is in a high energy state when it is not attached to the actin
                Then it attaches to actin where it is allowed to go to its relaxed state upon
                   muscle contraction
                This is the reason for rigor mortis:
                         Caused b/c the ATP is needed to relax the mucles
                         The myosin is most relaxed when you are in the contracted state
                The ability to reach down and contract mucles-
                         The power to do that isn’t ATP
                         It’s that the ATP took the myosin and put it into a state of high energy
                What is a high energy conformational state?
                         The energy is stored in peptide bonds
                         For each myosin head it is a single peptide bond
                         Your ability to move that massive amounts of iron around is the
                           tweaking of a single peptide bond that is twisted into a conformation
                           that it doesn’t like to be in by the hydrolysis of ATP
                       Just the binding of ATP that causes you to release
                       Then it’s the hydrolysis of ATP that tweaks that head
               Mg binds myosin, mg and ADP leave- myosin head changes conformation
               MG is a divalent effector ion (Zn, Mg, Ca often bind proteins in this way)
                       All we know is that it is necessary for this to occur
               Ca has bound, and when it binds it pulls troponin C out and then contraction is
               So, if you increase the concentration of calcium in muscles, you will get
   Motor neurons come out of the ventral horn (NOT DORSAL)
       o Come out to the same point of exiting that information came in
       o This info that comes down is a motor neuron that synapses onto multiple muscle fibers
               Some motor neurons will synapse onto more than others
               Numbers are approx. in the hundreds
       o The reason when you pick up a chair and you add pressure
               You are slowly engaging more and more motor units and engaging more muscle
                  fibers to do this
               As you pick up the recorder, you don’t need very many fibers to do it, so you can
                  calculate exactly how much you’ll need
                       You can calculate how much recruitment you need
                       Idea of adding motor neurons and having more and more muscle fibers
                           contract is called recruitment
                       Combo of a motor neuron and the fibers that it synapses onto is called a
                           motor unit
                               o Some synapse onto just one fiber, and others have as many as
       o When you have a motor neuron go down to a muscle it causes a single twitch
               Single action potential causes a twitch
               In order to get it to stay contracted, you need temporal summation
                       All action potentials on motor neurons are the same size
                       So, it’s the rate of firing that you vary
                       Either recruit more motor units or you fire faster
                               o Both methods work to increase the pressure on a muscle
   What happens inside the cell?
       o ATP is necessary for muscle contraction
       o More necessary for relaxation
       o Keep around very little ATP in your stores
               Have enough for only about 3-4 steps and your body is running out of ATP
               Substitute is creatine phosphate
                       Back up store that is found almost exclusively in muscles
                            Doesn’t work to ingest creatine phosphate, b/c when you put it in your
                             stomach it is dephosphorylated almost immediately. Also have
                             abundance of creatine in your body so excess will just be excreted
                          Works to phosphorylate ATP—considered substrate level
        o Glycogen is a stored starch that is largely stored in the muscles
                 Have a special myoglobin that will pull in oxygen (works better than hemoglobin
                    in your blood stream)
                 Provides you for another minute or so of an anaerobic state of ATP
                 Basically need oxygen to generate the ATP and have muscle contractions
        o Calcium
                 Interested in the contact between the T tubule and the S.R
                 Dihydropyridine receptor: DHPR
                 Ryanodine Receptor
                          In the S.R
                          DHPR is in the T-Tubule (which is also in the SR)
                 One receptor is voltage gated and then it has a tether that reaches down to the
                    ryano receptor
                 So the ryano receptor is actually a mechanoreceptor
                          It is actually being pulled open so that when you depolarize the
                             membrane you pull it open just like you do on an inflatable mattress
                          Then ca can come down
                 The separation between the 3 muscle types is based on this
                 When you get a depol of the T tubule, you pull open the ryanodine receptor
                          Ca comes in and that is what causes the reaction
        o Not going to be focusing on A band shrinking and z band doing etc.
   3 types of muscles: striated, smooth, cardiac
        o Striated is multi nuclear
                 Has organized sarcomeres
                 Has a SR
        o Smooth muscles
                 Monocellular
                 Unorganized—just go in any directions
                 Have unspecialized ER
        o Cardiac muscles
                 Also monocellular
                 Organized
                 Sparse SR
                 Hybrid between striated and smooth
   Smooth Muscle
        o Has very random cells with myosin and acting just going in any direction
          o   So that the cells just contract in general
          o   Do it in response to ca
          o   Ca enters and binds to calmodulin
                   The ca, calmodulin comes down and has an effect on the myosin light chain
                   This then phosphorylates the myosin head and then activates it
                   Smooth muscle moves very slowly based on an enzymatic reaction
                            Second messenger molec. (Ca) binds to an effector molec (calmodulin)
                                which has to go to an enzyme and it causes phosphorylation of the
                                myosin head, which just binds to any actin it can find to pull on
                            So, this myosin is diff from the one in striated muscles
                   cAMP actually inhibits in this pathway
                            inhibitory to myosin light chain kinase
                   ca is released using an IP3 pathway (g-protein mediated)
          o   ways to trigger smooth muscle
                   ca comes from extracellular stores
                   ca comes from intracellular stores
                   goes through previously described pathway
                   can be released by phospholipase c via G sub q pathway
                   norepinephrine binding to its receptor causes that to happen
                   epinephrine goes to a G sub s (means stimulatory) which goes to adenyline
                       cyclase, which produces cAMP
                            so, G sub s has inhibitory effect on contraction
                   norepi goes one way, and epi goes another way
                   beginning of the illustration of the entire second nervous system which is called
                       the autonomic system, which employs epi, norepi. And ach, often in opposing

     Final Exam will be patient questions
     Association Cortices
          o Attention
                   All the senses mean nothing if your brain doesn’t pay attention
                   Your eyes are doing what they’re doing and you’re reacting to the world around
                       you without observing
                   Do things not based on what you see, but what you sense
                   Will discuss phobias
                            Ppl afraid of things for reasons that don’t make sense
                                   o Woman who is afraid of a jar of pickles
                                            Not the smell, just the vision
                                            Photograph doesn’t have the same effect
                            Has to do w/ reactions that are occurring what her
                             retina sees and not what her V1 sees
                                  Proven b/c she will go into a panic attack using
                                     subliminal messages (no way that the v1 is able
                                     to pick up on the image, but the LGN did)
   Change Blindness
        Harvard study
        Neglect
               o Pay attention to things that are on the left or right side
               o Believe that ppl who concentrate in short bursts (like on an
                   exam) may have issues of neglect
               o Video of lady drawing half of cat
               o Eyes are controlled by the attention system (which is also the
                   system that makes you stop feeling your butt when you’re
                         It’s in the back of the parietal lobe
                         Theme for this exam: your left and right brains are not
                                 your left and right brains separate jobs
                                 often look for brain damage based on
                                     differential capabilities
                         when you point to the cat and show the lady that
                            something is missing, she notices it.
                                 So, it’s not that she can’t see it
                                 she is unusual in that she’s able to see this.
                                 Some ppl have a case of left side neglect so
                                     pwrful that you can point to that part of the
                                     table, and they won’t associate the new image
                                     with the previous image. They think it is
                                     completely different.
                                 Ex. Only eating half of the plate of food
        Left field neglect is called contralateral neglect
        Two types:
               o Damage on the right side is major
                         Vast majority of neglect is couched in your right parietal
                            lobe of your attention centers
                         Whereas if you have a loss of your attention center on
                            the left side(contralateral), you’ll just occasionally miss
                                          Ppl who have very pwrful retention of information
                                           (repeat entire convos, etc) one of the things missing is
                                           there corpus callosum
                                                Also have no talking between the two attention
                                                So, the right side only handles the left side, a
                                                   vice versa
                                                Means that brain will deal w/ the two diff things
                                                   in diff ways
                           Recognition
                                 o Patient who can’t identify faces, but can name objects
                                         Researcher prompted him with “who is it”
                                         Man doesn’t even recognize that the object is a face
                                         Can’t even say if she’s young or old
                                         If you could see his eyes, would be able to tell that his
                                            eyes are scanning the pic all over
                                                  Normally ppl look right between eyes when
                                                     talking to someone, so when you look at a pic,
                                                     tend to absorb it en masse
                                         Wasn’t even able to identify himself
                                 o Man who can’t identify objects
                                         “If it’s blue, it’s sky”
                                         Even a soccer coach, and he doesn’t know what a
                                            soccer ball is
                                         Loss of IT pathway
                                         No way of knowing what things are
                                         Means his left side is damaged.
                                         Has perfectly intact fusiform pathway on the right hand
                                            side, but the left hand side is missing the IT pathway
                                         Unable to connect words w/ objects
                                         Means that ppl are not objects
                                         Music, written text, living things, inanimate things—all
   3 different types of muscles
        o Remainder of slides compare muscles
        o Distinction between striated muscles and the other two is that the fibers are actually
             made up of multiple cells
                  Start out as a bunch of cells, and fuse together
                  Organized into neat bundles
                  Sarcoplasmic reticulum wraps around each of the bundles
        o Smooth muscles
                    Sarcomeres go many diff directions
           o Cardiac muscles
                    Have sarcomeres, with Z line between each one
                    Muscle fibers—just like striated muscles
                    But they split—see slide
                            One cell will be touching two other cells
                            Brings the muscle together when it contracts
                            Rather than pulling in one direction, it pulls in all three directions at
                            Want the whole thing to get smaller
                            So, the heart gets smaller in size when it beats
                    Burn up energy rapidly
                    Mitochondria in it burn up a large percentage of the energy you take in
     In striated muscles each fiber is innervated
           o And has nicotinic receptors
           o Each fiber is isolated from the other
     Smooth muscles
           o Generally innervated
           o Muscarinic receptors
           o Gap junctions between cells
     Cardiac muscles
           o Only a neuron coming to one part of the heart
           o Very local to the whole structure
           o One muscle
           o Has adrenergic receptors
           o Also has gap junctions
           o Another kind of junction called adherens junction: between the two cells
                    Very strong junction (called tight junction)
                    So, cell to cell in heart muscle are glued together quite well
                    b/c of gap junction, what happens in one cell will happen in the neighboring cell

     Question that will be on exam:
         o Patient whose heart has stopped
                  You have option of giving them epinephrine
                           If you think the person is dead, you give epi
                           Can actually kill someone this way
                  Times when you should give them atropine instead of epi
     Exam questions
         o Have already been told 3 questions that will be on the exam
        o  Every question on a previous exam is fair for the final
                 Especially if everyone missed the question
   Motor system
       o Targets include the viscera, bloodstream, various glands and skeletal muscles
       o Stuff that is coming down from the motor cortex (in the frontal lobe) have two general
                 Skeletal (voluntary)
                 Other (organs, enteric systems, blood vessels, glands)
       o Many types of descending pathways depending on the amount of control
                 Not true that when you go to reach for something that you just grab it
                 When ppl are drunk: don’t hit/grab things right
                 When you reach for something you don’t bend completely straight or you would
                   fall over
                         This process is under 5 diff controls
   Heart
       o Emphasizes that you have multiple motor control systems
       o Autodepolarizing
       o Has a pacemaker in it—series of cells
                 Those SA node cells (sino atrial) depolarize on their own
                 Do it cyclically
                 Have ca leaking, which builds up the ca current then get a K current response to
                   that and they depolarize and then repolarize
       o Even in the room, there will be ppl will arrhythmia’s (sp?)
                 Someone whose heart is not operating perfectly
                 Two primary sources
                         Tissue can dislocate or end up somewhere else—secondary sources for
                         The pacemaker cells end up in another location
                         When the pacemaker cells depolarize, causes through Gap junctions all
                            the atria to depolarize, but what if there is a source that is just beating
                            on its own?
                                o Atria could be contracting, and just before they are finished
                                     contracting, the ventricles start to contract, and then the
                                     current coming down from the AV node causes it to beat again.
                                o So there are three beats instead of two
                         The other thing that can cause problems is that you have a kind of
                                o This insulation is a lack of gap junctions between the cells of the
                                     upper and lower chambers
                                o What if there was a leakage and the signals from the top
                                     propagated downward?
                                    Then the heart is having ventricular arrhythmia, where
                                     the ventricles have two sources, one coming down from
                                     the atria and one coming up from the purkinje fibers
                                          This is a very serious kind of arrhythmia, b/c the
                                              muscles will be contracting and trying to push
                                              the blood in the wrong direction
o   Hearts are not running on their own entirely
        Respond to emotions
        In a cardiac myocite, know why the wave is square
                 Flattens out b/c you have a high conductance of ca that stays high for a
                    long period of time
                 Slow onset of K
                 The K response itself accelerates (just like it does w/ ca), which is why
                    the peak drops so rapidly
                 Have a kind of channel that kicks in when you start to repolarize
                        o Herg channel
                        o Found in the heart
                        o When you start to repolarize, get the secondary current
                        o All the sudden starts repolarizing rapidly
                        o Herg channels wait to open upon repolarization
                                  The depolarization prevents them from opening—
                                     actually causes them to close
                                  Repolarization opens them
        Ventricular cells have 3 currents that we’re interested in
                 Na, K, Ca
        Pacemaker cells autodepolarize as a wave of ca, and then a subsequent wave of
                 The K is voltage dependent
                 The ca is leak and ligand dependent
                 All of these channels also respond to another input, which is autonomic
                        o in striated muscles, Ach is going to cause an increase in Na and
                            K conductance
                        o in smooth muscles Ach leads to an increase in Ca
                        o in cardiac muscles Ach on a different kind of muscarinic
                            receptors causes a increase in the conductance of K and an
                            increase in the conductance of Na, and ca
                        o norepinephrine causes a decrease In K, and an increase in Ca
                            and Na
                 all of this is about the question for when to give someone epinephrine,
                    and when to give them atropine
                 when you add ach to a cell it will retard its beating—so it fires later
                             when you add epi or norepi, it will accelerate the firing
                                  o systems that deal with that are both the parasymphathetic and
                                       the sympathetic
                                  o this is the autonomic systems
                                  o entirely separate set of neurons that parallels your spine and…
   Adrenergic receptors are found in a lot of diff tissue
        o A1, a2, b1, b2
        o Not going to memorize
        o A1 smooth muscle in the gut, you get relaxation of the muscles
        o Smooth muscle bronchi, get relaxation w/ the betas
        o With the alphas also get relaxation
        o Heart muscle you get positive ionotropic effect, cause it to beat faster
        o w/ alpha 2 receptors
                 smooth muscles have contraction
        o alpha 1
                 relaxation
        o have receptors that depend upon what type of receptor it is, elicits diff response
   How do you control motor function?
        o Actually have a motor system that descends from the motor cortex
                 Doesn’t stop anywhere—goes right down the spine, where it will go out the
                     ventral side
                 And then control the muscle on the motor neuron
        o Motions using only that pathway are rough
        o Need to be able to be more smooth
        o Reticular formation, attention orientation (colliculus) and on to the cerebellum
   Have collicular spinal tract (orientation pathway)
        o Decussate above the midbrain boundary at the superior colliculus, which is receiving
            visual info
        o The visual info comes across, goes down, and you can control mucles
                 So, this is part of a reflex pathway
   Red nucleus (rubrospinal tract)
        o Also decussates high
        o Goes across to the other side and it descends all the way down where you synapse on
            motor neurons
   Many of us didn’t get the question about understanding the layout of the spine
        o Difference between propioceptive info and nociceptive info and mechanosensory
   So, keep in mind what kind of damage would separate out this motor control
   As you think about descending motor systems:
        o What type of lateral spinal damage would allow you to distinguish between the types of
            motor control systems that would be affected
        o This would be manifested in a patient in diff behaviors
   The red nucleus is cerebellar
   Vestibular nuclei come down to the medulla
   Pontine reticular formation
   When you choose to do something, two systems are engaged
        o One system comes down from the primary motor cortex
                 Some secondary processing in the basal ganglia
                 Comes down, and it’s not really going through the thalamus
                 Doesn’t decussate until you get down to the pyramidal region (medullary)
                 Then you go down the lateral cortical spinal tract
        o The reticular spinal tract is medial
                 Exact same stimulus is coming down
                 Decussates at a diff place
                 So, it’s a diff set of neurons, but the source is the same
                 If you reach for the French fries and spill them—it’s the fault of the reticular
                    spinal tract
                 Signal comes down and it splits—massive amount of connections, and no idea
                    how it works
                 Coordination of your body around some intended motion
                 Finest control you have
                 Even more fine than the cerebellum
                 But it is still largely dependent on descending motor afferents
                 Reticular regions in demand for study—b/c they are rare
                 Hint: pick up cup w/ right hand, but w/ left hand break glass every time
   Hypothalamus is receiving all the sensory input (through the amygdale)
        o All the memory and limbic system info comes out through VTA
        o Whole pathway is feeding into the hypothalamus
                 Causes your body to be under the control of the autonomic system
   Somatic motor pathway
        o Starts at the CNS goes out to the skeletal muscle
                 Synapse in between
   Autonomic Nervous system (comprised of sympathetic and parasympathetic)
        o Has a secondary locus
        o Ganglia that process this info
        o On either side of the spine and it process info that’s going to go to targets that are
            nonskeletal (smooth muscle, cardiac, glands)
        o Quite often it’s the same circumstance that causes the sympathetic and
            parasympathetic to engage
        o Perception of fear, tension
   Ppl who are so afraid of dogs that body will do weird things just b/c of perception
         o Heart will speed up
         o Bronchi will open up
         o Pupils will dilate
         o Bladder will start squeezing faster
         o Indigestion
         o Not ovulate
         o Immune systems shuts down (why you get sick during finals)
         o Body manifest these things b/c of perception
   4 f’s
         o Feeding, fighting, fleeing, fright, sex
   Hypothalamus is responsible for feeding notions
         o Sympathetic ganglia of the autonomic system are responsible for fright, fleeing, fighting,
   Have adrenergic neurons which are post ganglionic
         o Info is coming up and down that spine and it’s going through the system
         o These ganglia that are off to the side (like a secondary spine)
         o Things like pupils dilating and swallowing
         o Bronchi is lungs get dilated as a result of the sympathetic system engaging
         o Heart speeds up
         o Stomach actually becomes less motile
                  Don’t want to digest food
         o Liver mobilizes sugars
         o Shut down the intestines
         o When you have sympathetic stimulation of the kidney, there Is no counterpoint
                  Liver controlled by insulin and glucagon also
                  If your sympathetic system is triggered enough, it triggers the adrenal glands to
                    dump adrenaline into the bloodstream—becomes systemic
                  If you stimulate the sympathetic systems sufficiently you will trigger the adrenal
                    glands to release epi and norepi, adrenaline will dump into your bloodstream,
                    and you no longer have targeted stimulation, you have systemic stimulation
   Male arousal—doesn’t matter if it is inhibitory or excitatory
   Female arousal—stage thing. Sympathetic and then parasympathetic
   Parasympathetic system affects the same things
         o Except for bladder
         o Pinch down pupils, constrict bronchi, shut heart down, remobilize stomach gallbladder,
            pancreas, digestive system
   The sympathetic system is only coming from thorassic and upper lumbar regions—like a second
   Parasympathetic controlled in brainstem and…
   Efferent info coming out of the lateral horn
         o Sensory cell bodies in dorsal root ganglion
   Ventral horn is the lateral horn of the spine?
   Nerve comes out, loops around and gets processed in the sympathetic trunk
        o So, the sympathetic system gets a say in what you’re going to do
        o Gets processed a second time
        o Also process up and down
                 Parallelize them
                 Another clue to anterior/posterior spinal damage is whether or not the
                     sympathetic system engages systemically or just in some reions
   Parasympathetic ganglia
        o Come down and have parallel path and have a single process
        o While is sympathetic you’re engaging lots of systems, the parasympathetic is just trying
            to reverse that
        o There is very coarse control
        o Whereas the symp. System is trying to match your state of arousal to the stimuli
        o Notion where you can have symp. System get out of control and the para system starts
            to take over your body
   Need to understand slide of slice through spinal column
        o Dorsal horns
        o Descending pathways that are grouped into two general groups
                 Lateral—largely voluntary
                 Ventral, medial pathways—others
                 Tecto spinal tract= colliculus
   For every notion of control that you come up w/, there will be multiple pathways of motor
        o Most obvious is that you choose to pick something up, reach down and you do
                 Neuron coming down from the frontal cortex descends the spine, comes down
                     and synapses at the point where you control your motor neuron to your arm
                 No finesse, just grabbing
        o If that same source of info is also the superior colliculus and vestibular nuclei you’re
            going to come under the control of maintaining balance
                 Vest control= posture
        o Reticular formation- subtle things
                 Tells you how hard to squeeze, how smooth your motions are, and added
                     subtleties of balance (b/c it goes on both sides of the body)
        o Red nucleus
                 Control checks w/ the cerebellum
                 The cerebellum eventually can drive these types of behaviors by itself
                 It’s learned motor control
                 Motor cortex does not learn
   Lateral pathways have two basic things of control
          o     Descending pathway that comes all the way down, past the midbrain, past the medulla,
                decuss. At the pyramidal decussation and finally synapses where it needs to go out
            o Whereas the cerebellum comes in at the red nucleus decuss above the medulla and the
                cerebellar input, is going to short circuit the other pathway
      One way of determining the diff between these two
            o when someone is sleeping, can drag something across the bottom of their foot, and if
                they have a normal plantar response their toes will curl down
            o however, if they have a diff response (bibenski sign) toes will curl up
            o depends on which pathway is controlling the response
            o one is something you see in babies, the other in adults, or adults w/ upper motor
                control damage
      ventral medial pathways
            o come from superior colliculus
            o comes down and crosses almost immediately
            o comes down tecto spinal tract
            o does not stop in medulla
            o also have vest. Nucleus that is low in medulla that gives control from vest. System
                     this has to be shorter and quicker in order to be able to control posture
      all have to do w/ the pontine reticular formation

April 17, 2009
      New topic each lecture from this point on
      Descending pathways has to do w/ info that is leaving the brain and going down to the rest of
       the body
           o Have pontine reticular formation
           o Hypothalamic coming down to pineal gland
           o Inner peduncular info going to cerebellum
           o Also want to talk about where the sup. Coll. Info is going
           o Red nucleus and info coming from primary motor info
      See notes from class about diff pathways
           o Two kinds of motor control
           o Visceral= autonomic
                    You don’t think to your stomach to squeeze
           o Skeletal muscles
                    Gross motor control
                            Coming from the motor cortex
                    Offshoot from this (at the same time that you have gross motor control) also
                      have things manipulating targets other than the thing that you wanted to target
                            So if reaching for something other things besides the arm that is picking
                               it up
                         This is under pontine and medullary reticular control
                 Also have to coordinate all of this w/ other inputs
                 So, have the sensory cortex and systems that contribute to another type of
                         Coming into the vest. System and tectal system
                         The vest. System is postural control
                                o Also called antigravity, b/c constantly fighting the effects of
                                o Have to compensate for weight of arm when reaching
                         The tectal system is smooth control
                                o Basically taking in visual info and a little bit of hearing
                                o Superior colliculus
                                o The visual tectal control is orientation
                                          Allows you to orient your head and your eyes based on
                                             all this info to the thing that you want to do.—it’s hand-
                                             eye coordination
                         The vest. And tectal come together in the midbrain
   Receiving info from the vest. System, the tectal system and the motor cortex is the red nucleus
       o Rubrospinal tract
       o Goes in two directions
                 All the sensory info goes in, all the motor info goes in as well
                 So, for every action that you do there is sensory info coming up, motor info
                     coming down, and right in the middle is the cerebellum
                 The cerebellum sends controls up and sends info down
                         When it does this entirely possible that while cortex can learn how to
                             walk up steps
                         The cerebellum
                         Ex. In class of standing on block, walking on steps.
                                o When climbing stairs, must coordinate the two legs movements
                         This coordination is hard for the cortex to process
                         The information eventually has a cerebellar loop
                                o This is a reflex loop for higher learned functions
                                          Guitar, stairs, backflips, etc.
       o Ppl who have cerebellar lesions can’t drink water
       o Cerebellum receives thalamic info
                 This info is vest., and others
                 Receives info from the medulla
                 Looks at what primary cortex intends to do
                 So, sensory info is being coordinated w/ the choice of what your sensory and
                     motor cortex chose to do
                         So, based on the sensation, you make a choice of what to do
                          Cerebellar reflex is faster than using cortical functions
   Basal ganglia
        o Another refinement of your motion
        o Know about what they do, b/c when they fail, we can see what happens
        o Makes no sense that they have this function b/c of the geography of the brain
        o Controls unwanted motion
                  When you are sitting, your muscles are not soft
                  Not really soft unless deep asleep or dead
                  If it weren’t for the fine control, your muscles would be constantly battling
                      which way to turn your wrist
                  Radialis action common detection of loss of control of basal ganglia
        o Tremor= indication of basal ganglia problems
        o Basal ganglia deal w/ the motor cortex directly, whereas the cerebellum deal with the
        o All of the upper motor systems, which includes the lower motor cortex and brainstem
             going down to the lower motor systems are going to be coordinated in that way
   Picture of brain
        o Pons that extends back to cerebellum
        o Peduncle
   Tectal tract is coming through medulla
        o Info comes in from 8th cranial nerve
        o Going to the nuclei, which descends—medial, not lateral
   Superior colliculus- tectum
        o Deals w/ vision and VOR response, how you track things
        o A lot of hearing info from the 8th cranial nerve was ipsilateral
   Compare the descending pathways
        o Vest. Nucleus coming down vest. Tract, which splits
                  Has to control muscles on the opposite side of the body in opposite ways
        o The tectal pathway decussates and descends rapidly
                  Tectal spinal tract
                  Parallel pathway to the vest. System
   Contained in the brainstem have many nuclei
        o Nuclei of raphe—deal w/ descending pathways that numb you when you have pain
   Substantia nigra- deals w/ dopamine
        o Part of the basal ganglia
        o Deals w/ parkinson’s
        o Is actually black
        o Very deep in brainstem
        o Has to do w/ motor control
        o Controlling the fine motor control
        o Afferents are going up
        o    Substantia nigra is part of a motor loop
                  Motor cortex says it wants to do something, basal ganglia chooses not to
                  So, basal ganglia is constantly inhibiting
                  Dopaminergic pathways
   Substantia nigra + red nucleus= tegmentum
        o Cerebellum talks to these pathways through the red nucleus
   Two instinctual controls are in the center of the spine, while the learned controls and the gross
    controls are to the outside
   Red nucleus really is red
        o Decussates high, above the medulla
        o Goes down the rubrospinal tract
        o If you see someone exhibiting motor control issues, you’d know where the damage is in
             the spine (both laterally and vertically)
   Sensory info comes up, goes over to motor control, comes back down
        o Eventually, you can short circuit that and the cerebellum takes over
   You have a collection of extremely interconnected neurons
        o Has two tracks that controls both sides of the body
        o For very fine/smooth motion
        o Ppl who have reticular lesions tend to have jerky motion
                  Can tell b/c also affects vest. Descending outputs
                  When you walk, tend to point your feet in the direction that you’re going to go
                  When you watch ppl, you can tell where the lesion is based on how their foot
                     hangs when they’re walking
                  If foot is pointed in the direction that they want to go, that is the reticular
                     formation that is doing that
                          Allows you to roll from your heel to your toe
                          Ppl who land on their toe first have reticular issues
   Reticular formation
        o Receives info that is coming down
        o Pontine reticular formation- excitatory pathway
        o Medullary reticular formation- mediating pathway
                  Has an inhibitory pathway
                  Way of balancing the muscles to keep them in control
        o The level of competition between pontine and medullary that makes the muscle have
             fine, smooth control
   Descending pathways
        o Reticular formation splits to both sides
        o Have both left and right reticular, pontine and medullary control
   Go backwards w/ descending fibers, red nucleus, cerebellum
   So, the cerebellum has massive output that is modulating what you choose to do
   Interested in the arrangement of the premotor and motor cortex
        o    Cerebellum talks to the premotor cortex
        o    Area 5 and area 7 have some kind of associative info coming to them from other senses
             in visual cues
         o Then have prefrontal cortex—who you are
         o Then have motor area—area 4
                   This is the thing that says what you want to do
         o Primary motor area and supplemental motor area—area 6
   Basal ganglia
         o Just above midbrain
         o Just off to the side
         o Talk to the motor cortex
         o Do this in a loop
         o Receives info and then sends out info to the reticular formation
         o Very complex—need to know layout and the pathways of the info going through them
             for final
   “lie to me”
         o Tv show that relies on the understanding of basal ganglial control
         o Microticks/micromotions have to do w/ the fact that the basal ganglia allows you to
             keep a steady smooth face, and have controlled motions
                   When it is overridden by the emotional input, this allows you to have a lack of
                   Actually get parkinsonian movement
                           Eye blinking to expressions that you would normally fight
   Basal ganglia receives sensory info, premotor info, reports
         o This reports to medulla comes back to the cerebellum, then loops all the way back
   Motor loop number 1
         o Prefrontal cortex and motor cortex and sensory info
         o Sensory info, emotional state, and motor intent all go into the basal ganglia
         o Then go to the VLO (don’t know what it stands for)
                   Is a nucleus that is part of the ventral lateral region of the thalamus
                   Reports back to the motor, which will then send those signals down
         o All of these control through lateral and ventral, medial pathways stuff that is happening
             in the motor neurons
         o All gets checked in the basal ganglia
   See slide of anatomy
         o Thalamus w/ what looks like headset wrapped around whole thing
   Cortex has info about your intent
         o That info enters into the caudate and the putamen
         o Comes down and checks w/ the substantia nigra, which modifies the signal
         o Then goes to the globus palladus (sp?)
         o Side trip to the subthalamic nucleus
        o    Finally goes back out to the thalamus and then back up to the cortex
        o    If you wipe out any of these things, you get an effect
                   We know this b/c of disease
                   Disease of the subthalamic nucleus
                   Disease of the substantia nigra
                   Disease of the caudate and putamen
   See slide
        o Frontal cortex has effects, supplemental cortex is being effected
   Info from the cortex comes down
        o Goes through the caudate and putamen
        o Loops through the substantia nigra
        o Then you have an inhibitory effect, which inhibits the substantia nigra
                   If you don’t have much inhibition, then you get excitatory
        o Then have another loop that goes through another part of the substantia nigra
        o Slowly inhibiting the thalamus
        o General control is to inhibit unwanted motion
   So, cortical info comes in, and effect is that via the thalamus you’re going to hold back the
    unwanted motion
   Parkinson’s
        o Dramatic reduction in amount of substantia nigra
   Huntington’s
        o Autosomal dominant
        o Dramatic loss of tissue in the caudate and putamen
        o Basically the cells have a gain of function that causes them to fade very quickly
   You have two motor loops
        o One going through the basal ganglia, which is inhibitory
        o And one through the cerebellum which is excitatory
        o Cerebellum tends to instigate motion, and the basal ganglia tends to shut it down
   Cerebellum is the bridge to the next subject
        o Is two things
                   Motor control
                   Learning
        o Another little mini brain
                   Have motor info coming in
                   Also have sensory info coming in
                   Makes very basic decisions about what you do, by watching what you do
                      throughout your life
                   Start out with a blank cerebellum
                   Has been trained since then

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