The ability to plan and execute movements is fundamental to the survival of animals. Inherent in these movements is the necessity for accuracy, accomplished through careful planning and preparation. Notably, this planning and preparation of movement is disrupted in individuals with autism spectrum disorder or Asperger syndrome. In normal functioning brains, during the planning of a movement, collection of evidence allows for environmental stimuli, internal states and projected consequences to be taken into account prior to making confident, robust movements. These preparatory states involve complex sensorimotor transformations, assessment of motivation, and reward association. How are these transformations and associations represented among various regions of the brain comprising the sensorimotor pathway? Previous studies recording neural activity from the primary (M1) and secondary (M2) motor cortices have revealed fundamental principles about their activity during movement behaviors, showing changes in activity during and immediately prior to (i.e. in preparation for) movements. Similarly, recordings made in the posterior parietal cortex (PPC) have shown selective modulation of activity prior to movements in a planned direction. Activity prior to movement in each of PPC, M2 and M1 likely plays an integral role in preparing the motor cortex for proper movement execution. Thus understanding their interaction at a network, or population level, will provide a better understanding of the coding strategies surrounding movements. This proposal utilizes in vivo calcium imaging of mice performing a novel memory-guided two-choice sensorimotor discrimination task and has two specific aims, Aim 1: To identify the information flow of preparatory activity between PPC, M2 and M1.
Aim 2 : To test how population dynamics during preparatory activity affect subsequent movement related activity and movement execution.
A central question of neuroscience is to understand how the collective activity of a network of neurons prepares and executes accurate motor output. Inherent in the accurate execution of movement is the necessity of the network to sufficiently prepare itself for movement sequences. Therefore, understanding how the motor network prepares and executes upcoming movements will provide insight of how the motor system organizes itself, and how this organization might be disrupted in mental disorders that challenge normal movement execution, such as autism spectrum disorder and Asperger syndrome.
