We pick up objects and manipulate them in our hands hundreds of times each day. Our arms and hands work together gracefully to complete these actions. How the motor system articulates the joints of the arm and hand to specific points in space at precise moments in times, remains elusive.

We study how the primate brain controls the arm and the hand on a moment-by-moment basis during reaching and grasping. Our efforts are currently focused on primary motor cortex (M1) as it is one of the most important brain structures involved in arm-hand control. Our goal is to uncover the organizational principles that confer on M1 the capacity to generate coordinated arm-hand actions.

The overarching questions driving our research include:

(1) What is the spatial-temporal organization of M1 neural activity that supports reaching and grasping?

(2) How does M1 connectivity support its role in arm-hand control?

We address these questions in parallel projects that we are pursuing in macaque monkeys and in squirrel monkeys.

(1) Spatial-temporal organization of M1 activity that supports reaching and grasping

We use optical imaging in behaving macaque monkeys to determine the spatial organization of populations of M1 neurons that encode reaching and grasping. Next, we strategically place linear electrode arrays into M1 zones that were identified with optical imaging. This step allows us to recording neural activity from all layers of cortex, which provides insight into the temporal coding of movement in M1. Combining optical imaging and neural recordings reveals the spatial-temporal organization of neural activity in M1 that supports reaching and grasping. Read more…

(2) Functional organization of M1 connectivity that supports arm and hand control

We use intracortical microstimulation (ICMS) to map the organization of the forelimb representation in anesthetized squirrel monkeys. We then study the connectivity of M1 sites using ICMS in conjunction with optical imaging. Applying this approach to dozens of sites that control the arm and the hand reveals the principles that govern the spatial organization of the cortical connectivity that supports M1 functions. Next, we rely on the connectivity map to guide microelectrode placement for the purpose of interrogating neural interactions that occur between connected zones. Thus, we use ICMS to drive activity in one zone while we simultaneously recording neural activity in a connected zone. Read more…

Get involved!

We have multiple training opportunities. Prospective postdocs and graduate students are encouraged to contact Omar directly.