Cortical population coding of consumption decisions

On Tuesday June 30th, Donald Katz will be giving a talk on Cortical population coding of consumption decisions.

The talk will be hosted at 4 pm, while at 5.15 pm we will host a virtual pub chat with the speaker. Further details on how to join both sessions will be sent through our mailing list! To join our mailing list, follow the instructions here https://cortexclub.com/join-us/

Abstract:

The moment that a tasty substance enters an animal’s mouth, the clock starts ticking. Taste information transduced on the tongue signals whether a potential food will nourish or poison, and the animal must therefore use this information quickly if it is to decide whether the food should be swallowed or expelled. The system tasked with computing this important decision is rife with cross-talk and feedback—circuitry that all but ensures dynamics and between-neuron coupling in neural responses to tastes. In fact, cortical taste responses, rather than simply reporting individual taste identities, do contain characterizable dynamics: tastedriven firing first reflects the substance’s presence on the tongue, and then broadly codes taste quality, and then shifts again to correlate with the taste’s current palatability—the basis of consumption decisions—all across the 1-1.5 seconds after taste administration. Ensemble analyses reveal the onset of palatability-related firing to be a sudden, nonlinear transition happening in many neurons simultaneously, such that it can be reliably detected in single trials. This transition faithfully predicts both the nature and timing of consumption behaviors, despite the huge trial-to-trial variability in both; furthermore, perturbations of this transition interfere with production of the behaviors. These results demonstrate the specific importance of ensemble dynamics in the generation of behavior, and reveal the taste system to be akin to a range of other integrated sensorimotor systems.

Hippocampal disinhibitory circuits: cell types, connectivity and function.

On Thursday, Lisa Topolnik, researcher at the Centre de recherche du CHU de Québec and professor at the Department of Biochemistry, Microbiology and Bio-informatics of Laval University’s Faculty of Science and Engineering, will be giving a talk on Hippocampal disinhibitory circuits: cell types, connectivity and function. 

The talk will be hosted at 5.30 pm, while at 6.45 pm we are having a virtual pub chat with the speaker. Further details on how to join both sessions will be sent through our mailing list! To join our mailing list, follow the instructions here https://cortexclub.com/join-us/

Mini-symposium on the Neuroscience of Cognitive Development

We are proud to host this virtual mini-symposium in collaboration with the University of Cape Town Cortex Club.

Speakers will highlight research on the developmental processes underlying cognitive control and the effects of environmental risk factors on neural pathways in human cognitive development.

Gaia Scerif, from University of Oxford, will be giving a talk on Using developmental cognitive neuroscience tools to investigate mechanisms of atypical cognitive control, followed by Kirsten Donald, from University of Cape Town, who will give a talk titled Neuroimaging the very young high risk brain: lessons from a south African birth cohort.

The mini-symposium will be hosted at 2 pm, while at 3.45 pm we are having a virtual pub chat with the speakers.

Further details on how to join it will be sent through our mailing list.

Striatal circuits for reward learning and decision-making

Prof. Ilana Witten from Princeton University will be giving a talk on ‘Striatal circuits for reward learning and decision-making.’

The talk will be hosted online at 5.30 pm, while at 6.45 pm we will host a virtual pub chat with the speaker. Further details on how to join both sessions will be sent through our mailing list! To join our mailing list, follow the instructions here https://cortexclub.com/join-us

Abstract:

How are actions linked with subsequent outcomes to guide choices? The nucleus accumbens (NAc), which is implicated in this process, receives glutamatergic inputs from the prelimbic cortex (PL) and midline regions of the thalamus (mTH). However, little is known about what is represented in PL or mTH neurons that project to NAc (PL-NAc and mTH-NAc). By comparing these inputs during a reinforcement learning task in mice, we discovered that i) PL-NAc preferentially represents actions and choices, ii) mTH-NAc preferentially represents cues, iii) choice-selective activity in PL-NAc is organized in sequences that persist beyond the outcome. Through computational modelling, we demonstrate that these sequences can support the neural implementation of temporal difference learning, a powerful algorithm to connect actions and outcomes across time. Finally, we test and confirm predictions of our circuit model by direct manipulation of PL-NAc neurons. Thus, we integrate experiment and modelling to suggest a neural solution for credit assignment.

High precision coding in visual cortex

Dr. Carsen Stringer from HHMI Janelia Research Campus, will be giving a talk on ‘High precision coding in visual cortex.’

The talk will be hosted online at 2.30 pm, while at 4.00 pm we will host a virtual pub chat with the speaker. Further details on how to join both sessions will be sent through our mailing list! To join our mailing list, follow the instructions here https://cortexclub.com/join-us/

Abstract:

Single neurons in visual cortex provide unreliable measurements of visual features due to their high trial-to-trial variability. It is not known if this “noise” extends its effects over large neural populations to impair the global encoding of stimuli. We recorded simultaneously from ∼20,000 neurons in mouse primary visual cortex (V1) and found that the neural populations had discrimination thresholds of ∼0.34° in an orientation decoding task. These thresholds were nearly 100 times smaller than those reported behaviorally in mice. The discrepancy between neural and behavioral discrimination could not be explained by the types of stimuli we used, by behavioral states or by the sequential nature of perceptual learning tasks. Furthermore, higher-order visual areas lateral to V1 could be decoded equally well. These results imply that the limits of sensory perception in mice are not set by neural noise in sensory cortex, but by the limitations of downstream decoders.