This seminar will begin at 4:00 pm at the Jerome L. Greene Science Center on Columbia University’s Manhattanville campus (L7-119). Light refreshments will be available starting at 3:30 pm.

This month's speakers:

Avner Wallach, PhD (Sawtell Lab): "Internal models for active sensing in freely swimming electric fish"

Active sensing introduces sensory ambiguities that necessitate an internal model predicting the sensory consequences of motor behavior. Past studies in immobilized weakly electric fish have shown that motor-related corollary discharge is used to predict and cancel the effects of self-generated motion on electrosensory input, but it is unknown whether such mechanisms hold during natural exploration. To test this, we developed methods for long-term neural recording in the electrosensory lobe (ELL) of fish during free exploratory behavior. We demonstrate that motor-based internal models are insufficient in canceling self-generated distortions resulting from non-linear interactions between the fish and its environment. We suggest that electrosensory feedback plays a crucial role in resolving these interactions to enable precise and reliable perception of the external environment.

Laureline Logiaco, PhD (Abbott Lab): "Flexible, robust and efficient motor sequencing through thalamic control of cortical dynamics"

The mechanisms by which the brain acquires an extensive library of motor motifs and flexibly strings them into arbitrary sequence orders are unclear. To investigate this issue, we have developed an anatomically constrained model in which inhibitory basal ganglia (BG) output neurons project to thalamic units that are themselves bidirectionally connected to a recurrent cortical network. During movement sequences, BG neurons exhibit sustained activity that switches at boundaries between sequence components. Assuming that these BG signals are the predominant source of input to many thalamic neurons, we find that the remaining thalamic neurons that interact freely with cortex can exert powerful control over cortical dynamics, thereby giving thalamocortical loops the ability to direct robust and flexible motor sequences.

This seminar is part of the Zuckerman Institute Postdoctoral Seminar series. For questions about this or future seminars, please contact series organizers Chris Rodgers, PhD, or Amy Norovich, PhD.