Form cerebrum

Document Sample
Form cerebrum Powered By Docstoc
					        Functional Connectivity between Cerebellum and Cerebrum: A Resting-State fMRI Study
                                                                                      生醫電資所 R97945037 游雅芝
   In the past studies, the functions of cerebellum was always to be think as just contribute to the motor control
system, this led that most of researches focused on the connection between psychological task/stimulation and
cerebral activation, and the function of cerebellum was always ignored in previous functional MRI investigations.
But in these few decades, more and more researches had found that cerebellum might take part in many
different kinds of brain functions other than just motor control. However, previous researches rarely put notice on
cerebellum and its relationship of cerebellum with cognitive behaviors. In recent years, some studies had started
to focus on the cerebellar functions. In addition to build up the anatomical atlas of cerebellum by using MRI [1, 2],
other researches also tried to explore the cerebellar contributions in higher order functions [4]. These revealed a
new sight of understanding the cerebellar functions.
   Well-designed task was always necessary for traditional functional MRI experiments to investigate the
activation distribution which represented the evidence of neural activity. In 1995, Biswal et al. introduced the
phenomenon of low-frequency fluctuations in the brain when people stay in a relatively resting-state condition
and had fMRI scan [5]. According to the seed point selection, the functional connection network between seed and
other brain regions could be presented. This method gave us a new powerful tool to investigate the brain
functions and the functional connectivity within whole brain [6, 7]. Since resting-state fMRI experiment can provide
an easier way to study whole brain functions rather than just specific regions under traditional task-designed
studies. Here I propose to find out the relationships within cerebral-cerebellar networks by using this tool to
acquire the information about the interactions between cerebellum and cerebrum. From the knowledge of
neuroanatomy and pioneered investigations, we could know that cerebellum is highly connected with cerebrum
both in structural and functional. The utilizing of resting-state fMRI analysis method might provide a set of
connectivity maps to divide cerebellum into different regions where separately correlated to the functional areas
of cerebrum.
  My research plan includes two main aspects: (1) apply this method to show that the functional connectivity
map (FC map) can reflect the relationships between cerebrum and cerebellum (Aim 1); (2) build up a cerebellar
map which links to each Brodmnn areas of cerebrum (Aim 2). It is well defined that cerebellum cooperates the
motor control with cortex [3] and the connections between these two parts were already established by previous
studies. Here I will try to use FC maps to display these kinds of networks. Based on past investigations that
cerebellum is involved in many other works, FC maps will be utilized here to develop correlations within entire
cerebrum and cerebellum.
Specific Aim 1: I will use the activation regions on motor cortex (BA 6) of traditional task-based fMRI
experiments as seed points to calculate the correlation coefficients within whole brain signals of resting fMRI
data and generate the FC maps.
Hypothesis 1: Specific part of motor cortex and cerebellum cortex cooperate together to control particular body
motion, and the functional connectivity will show that these parts are highly correlated. The patterns may be
similar to the result of traditional BOLD fMRI experiments.
Specific Aim 2: I will combine both structural and functional information between different subregions of
cerebellum with Bradamnn areas of cerebrum.
Hypothesis 2A: Since the cerebellum plays a role in varied functions other than just motor control, each part of
cerebellum should have highly correlated to specific areas of cerebral cortex.
Hypothesis 2B: The whole set of FC maps may reflect some defined cerebral-cerebellar functional networks.
 This research is trying to investigate the cerebellum functions in a new aspect by applying the tool of non-tasked
method which differs from traditional task-based studies. And I hope the results can help future investigations to
design appropriate experiment task when explore specific cerebellar regions in detail.
 1. Jörn Diedrichsen, et al., (2009), A probabilistic MR atlas of the human cerebellum
 2. Nikos Makris, et al. (2005), MRI-based surface-assisted parcellation of human cerebellar cortex: An
     anatomically specified method with estimate of reliability
 3. Wolfgang Grodd, et al. (2001), Sensorimotor Mapping of the Human Cerebellum: fMRI Evidence of
     Somatotopic Organization
 4. Catherine J. Stoodley, et al. (2009), Functional topography in the human cerebellum : A meta-analysis of
     neuroimaging studies
 5. Bharat Biswal, et al., (1995), Functional connectivity in the motor cortex of resting human brain using
     echo-planar MRI
 6. Christophe Habas, et al. (2009), Distinct Cerebellar Contributions to Intrinsic Connectivity Networks
 7. Jill X. O’Reilly et al., Distinct and Overlapping Functional Zones in the Cerebellum Defined by Resting
     State Functional Connectivity, Cerebral Cortex, 2009 Aug 14

Shared By: