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:

Tristan Geiller, PhD (Losonczy Lab): "Imaging interneuron diversity and influence on their postsynaptic pyramidal cell targets in the hippocampus"

Excitatory circuits in the hippocampus are tightly constrained by inhibition from distinct subpopulations of local GABAergic interneurons, but the direct influence of these various inhibitory cell types on the firing activity of a single pyramidal cell is still unknown. Here, I will present a new technique that I implemented in the lab that allows me to perform monosynaptic tracing from a single hippocampal pyramidal cell and record the activity of its presynaptic interneurons in vivo during spatial navigation. I used this method in combination with a microscope based on acousto-optic deflectors (AOD) to obtain high-throughput recordings of molecularly-defined interneurons.

Danique Jeurissen, PhD (Shadlen Lab): "Deficits in decision making after causal manipulation of neural activity in parietal cortex"

Neurons in the lateral intraparietal area (LIP) of macaque monkeys represent ongoing decision processes. However, silencing of LIP has been reported to not affect choices in a perceptual decision-making task. We investigated if compensation from other brain areas could explain such null effects. We inactivated LIP using pharmacology and chemogenetics in monkeys performing perceptual decision-making tasks. We found that choices were biased towards the ipsilateral choice target, but only transiently. Behavioral effects dissipated within single sessions and across multiple sessions, suggesting that compensatory mechanisms can be recruited to recover cognitive functions.

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