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ANC Workshop Talks: Hugh Pastoll and Matthew Chalk, Chair: Ali Eslami

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  • ANC Workshop Talk
When Dec 13, 2011
from 11:00 AM to 12:00 PM
Where IF 4.31/33
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Hugh Pastoll
Recapitulation and exploration of in vivo circuit dynamics in vitro.

Field recordings reveal theta (4-12Hz) modulated gamma (40-120Hz) oscillations in Medial Entorhinal Cortex (MEC) of awake behaving rodents. Using optogenetic tools we find that local entrainment of the MEC layer 2 microcircuit at theta frequency generates field gamma oscillations. The field gamma is aligned with robust gamma inhibition onto stellate cells recorded in whole cell configuration. We find that the theta phase of stellate cell spikes can shift and is dependent on firing rate. Furthermore, we describe distinct network states that depend on the intensity of the local microcircuit stimulation. 

Matthew Chalk

Attention as reward-driven optimisation of sensory processing

Attention causes diverse changes to visual neuron responses, including alterations in receptive field structure and firing rates. While these changes are generally thought to reflect optimisation towards the behavioural task, what exactly is being optimized and why different tasks produce such varying effects is unknown. To account for the effects of attention on visual neuron responses, we hypothesise that the brain learns a probabilistic model that predicts how both the sensory input and the reward received for performing different actions are determined by a common set of explanatory causes. Attention-dependent changes to neural responses reflect optimisation of this internal model to deal with changes in the sensory environment (stimulus statistics) and behavioural demands (reward statistics). This framework is used to predict a range of experimentally observed effects of attention on visual neuron responses, as a consequence of simple underlying functional principles.