ABC -seminaari: How the brain learns in a complex world

Welcome to the Aalto Brain Centre (ABC) Seminar!

This seminar series is open for everyone. The seminar will be recorded.
The talk will be held online via Zoom at: https://aalto.zoom.us/j/63013749073.

Speaker: Dr. Nelson Totah, University of Helsinki, Finland

Title: How the brain learns in a complex world

Abstract: My laboratory studies brain activity during adaptation to an unpredictable and complex, multi-modal environment. I will present data collected from a head-fixed rat-on-a-treadmill apparatus that enables stimulus-response behavioral tasks, electrophysiology, and pupillometry (a non-invasive index of neuromodulatory neuron activity). In this talk, I will first show individual-specific strategies employed by rats during a task that requires learning to attend to stimuli in either the auditory or visual modality in a multi-modal task environment. Using pupillometry and brain-wide (32-electrode) EEG recordings, we have found that neuromodulatory brain centers are active during the remapping of cortical networks that occurs as rats change behavioral strategies and shift attention to learn about novel stimuli in a modality that was previously irrelevant to the rat. In the second part of the talk, I will demonstrate a novel ‘near-mistake’ behavioral paradigm in rats. In this task, rats are trained to run when they see one stimulus and remain immobile when they see another. Near-mistakes occur when the rat initiates an incorrect running response but realizes their mistake and stops before crossing a response threshold. We demonstrate that anterior cingulate cortex (ACC) single neuron firing rate and dimensionality-reduced neuronal population activity scale with the degree of ‘response conflict’ between moving and not moving. Based on the timing of the neuronal responses to conflict, we propose that the ACC has two neuronal ensembles supporting two cognitive functions: one is related to rapidly inhibiting in-progress mistakes and the other is related to detecting past mistakes in order to muster cognitive resources that will improve future performance during learning.

Bio: Dr. Nelson Totah earned his PhD at the University of Pittsburgh (USA), where he worked with Prof. Bita Moghaddam to perform the first single neuron recordings during a widely used attention task for freely moving rats. His work covered interactions between frontal cortex neurons and dopamine neuron activity during preparatory attention to an upcoming stimulus. Dr. Totah was a Marie Curie Postdoctoral Fellow at the Max Planck Institute for Biological Cybernetics (Tuebingen, Germany) in the laboratory of Dr. Oxana Eschenko where he established the first large-scale recordings of many locus coeruleus (LC) brainstem neurons simultaneously in any animal. His work demonstrated that, in contract to the long-held belief that LC neurons respond synchronously, LC population activity actually consists of a nuanced pattern of distinct ensembles that are independently active. Nelson is also a leader in science education and is the Founder and Vice Chairman of the Science National Honor Society, a US-based non-profit organization involving over 1,700 high schools in the US.