Skip to Content

Tue June 21

Speaker: Faezeh Jaganmiri (Dr. Rymer's group)

Title: Noninvasive Surface EMG Examination of Spontaneous Muscle Activity in Amyotrophic Lateral Sclerosis

Abstract: Diffuse, abundant distribution of spontaneous muscle activity can be a typical electrophysiological feature in many neuromuscular diseases. Examination of spontaneous muscle activity is regarded as a part of the routine clinical electromyogram (EMG) that relies on needle electrode. In this talk, we will present findings of using high density surface EMG techniques to explore key features of spontaneous muscle activity of a critical motoneuron disease, amyotrophic lateral sclerosis (ALS).

Speaker: Devjani Saha (Dr. Mussa-Ivaldi's group)

Title: Forces are represented in an intrinsic coordinate space.

Abstract: In order to make voluntary movements, the brain must transform trajectories planned in the extrinsic coordinate space of the environment into an intrinsic coordinate space of muscle activity.  In this study, we explore whether this is also true for force control.

The primary objective of this study is to establish a coordinate system for force control by observing how unspecified parameters of force vary across the workspace. Specifically, the task was to produce isometric forces in the transverse plane of a given magnitude at different arm postures. The direction of the force remained unspecified. Thus, in order to complete the task subjects could choose to apply forces in any direction along the plane. The data suggests that the direction of the applied force as well as the joint torque patterns varied with the configuration of the arm. Moreover, subjects applied forces in the direction that was associated with the lowest overall muscle force. These findings suggest that forces are represented in an intrinsic coordinate space and that the central nervous system applies a minimum muscle force criterion to set unspecified parameters of force control.