טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentLamfrom Yael
SubjectEstablishing an Experimental Platform to Study
Representation and Plasticity in Primary Sensory
Cortex Following Motor Task Learning
DepartmentDepartment of Medicine
Supervisor Professor Jackie Schiller
Full Thesis textFull thesis text - English Version


Abstract

Adaptive, flexible behaviour requires a motor system that can integrate new skills in response to new conditions, using motor plasticity; but in order to perform an action in the context of a certain task, sensory information on target location, body posture, organ position and feedback during motion has to adapt as well.

Cortical plasticity is a general term for changes that occur during development at the morphological level of neuronal connections and are expressed in the activation patterns of neuronal populations in cortical areas. Some of these changes can also occur in the adult due to pathological problems or following a novel experience. For example, the representation of certain body parts in the sensory cortex can expand or diminish following training, injury and over/under use; new movement trajectories or joint torques can be generated by the motor cortex; connections between different cortical areas can be strengthened or diminished. These changes, found in all levels of organization (i.e. from the molecular to the network), arise from the unique network structures of cortical and subcortical areas which allow salient environmental cues the access to synaptic level mechanisms via motivation and training.

In order to study sensory cortex plasticity in adults following learning of a novel motor task we had to set up a new platform in the lab that could enable us to follow the activity of multiple somas for many weeks in sensorimotor cortical coordinates during the acquisition and training phases.

The platform includes:

1. A head fixed motor task: we chose the reach-and-grab task, which includes a complex set of motions that require the participation of the motor cortex yet can produce a unified movement pattern in time. Its sensory components are yet to be resolved, which offered us many experimental variations. 

2. Visualization of neurons and their processes for many weeks: we established a multi-step surgery for viral injections and implantation of a chronic cranial window that enabled us to use genetically expressed calcium indicators.

3. Synchronization of behaviour and calcium imaging: we established a suitable Matlab and Arduino based set in our Tow-photon system.

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 The platform enabled us to start studying how morphology of dendrites and activity of neurons in sensory motor regions changes during learning of a motor task.