Quantitative Life Sciences Guest Seminar - Tuesday 8 November at 11:00am

[Quantitative Life Sciences]

*Quantitative Life Sciences Guest Seminar*

Tuesday, 8 November 2016, 11:00 a.m.
ICTP, Central Area, 2nd floor, old SISSA building

Eugenio Piasini - Neural Computation Lab, Center for Neuroscience and 
Cognitive Systems - Italian Institute of Technology, Rovereto (TN), Italy

*"* *Distinct timescales of population coding across cortex"*

Abstract:

The cortex represents information across widely varying timescales. For 
instance, sensory cortex encodes stimuli that fluctuate over 
milliseconds, whereas in association cortex behavioural choices can 
require the maintenance of information over seconds. It is poorly 
understood how the cortex achieves such diverse timescales of 
information coding. While recent work has identified different 
timescales in features intrinsic to individual neurons, the timescales 
of information coding in populations of neurons have not been studied, 
and population codes have not been compared in depth across cortical 
regions. In this talk, I will compare coding for sensory stimuli and 
behavioural choices in auditory cortex (AC) and posterior parietal 
cortex (PPC) in the mouse brain, as the animal performs a sound 
localisation task. I will show that population codes are essential to 
achieve long and diverse coding timescales, and that the statistical 
structure of the codes differs between sensory and association cortices.

Among PPC neurons, correlations that are not explained by task events 
("functional coupling") extend over long time lags, and contribute to a 
long timescale population code characterised by consistent 
representations of choice lasting over two seconds. In contrast, 
coupling among AC neurons is weak, shorter-lived, and results in 
moment-to-moment fluctuations in stimulus and choice information. This 
suggests that population coupling is a variable property that affects 
the timescale of information coding: relatively uncoupled activity in 
sensory cortex is key for signals that change rapidly to code temporally 
variable stimuli, whereas highly coupled activity in association cortex 
appears critical to form a consistent signal from which temporally 
integrated information can be read out instantaneously to drive behaviour.

Web page: http://indico.ictp.it/event/8056/

-- 
Erica Sarnataro
Group Secretary
Quantitative Life Sciences
The Abdus Salam International Centre for Theoretical Physics (ICTP)
Trieste,  Italy
Tel. +39-040-2240623
e-mail:qls at ictp.it