Peggy Series -- Research in Neural Coding and Cognition

Research

My research in a 1 min nutshell:

Expectations and the Bayesian Brain

Perception is modulated by our expectations and prior beliefs about the world. What are the theoretical principles underlying those changes? What are the signals that mediate them? What are the consequences of these changes for perception ? Can we account for those changes using the framework of Bayesian inference?
We build mathematical and computer models to address those questions. We also design psychophysical experiments to investigate how expectations and attention alter visual perception.

[1] M. Chalk, A.R. Seitz and P.Seriès (2010), Rapidly learned stimulus expectations alter perception of motion. Journal of Vision
[2] G. Sotiropoulos, A.R. Seitz and P.Seriès (2011), Changing expectations about speed alters perceived motion direction. Current Biology.
[3] N. Gekas, M. Chalk, A.R. Seitz and P.Seriès (2013),"Complexity and specificity of experimentally induced expectations in motion perception", in revision.

From Neural responses to Conscious Perception

How are neurons `read-out' to give rise to perception ? how many neurons are involved in a percept? how optimal is the read-out? How flexible is it? Can the read-out strategy change dynamically as a function of the task or context?
We build models to test different hypotheses, and design psychophysical experiments to test models' predictions.

[1] P.Seriès, A. Stocker and E.P. Simoncelli (2009), Is the homunculus aware of sensory adaptation?. Neural Computation 21(12), pp 3271-3304

The precision of the neural code

What's the precision of the neural code? How is information represented in populations of neurons? To what extent is the brain `noisy' ? What are the mathematical and statistical tools that are best appropriate to answer those questions?
Using information theory and computer simulations, we seek to answer those questions.

[1 ] P. Seriès, P. Latham and A. Pouget (2004),Tuning Curve Sharpening for orientation selectivity: coding efficiency and the impact of correlations, Nature Neuroscience . 7. 1129-1135. [2] S. Yarrow, E. Challis and P. Seriès (2012). Fisher and Shannon information in finite neural populations. Neural Computation.

Neuromodulation and Mental Disorders

I have a growing interest for the understanding of the influence of neuromodulation on neural activity, decision-making processes and the study of mental disorders, such as schizophrenia and depression. We use the framework of reinforcement learning models and Bayesian inference to understand the factors behind individual variability and clinical disorders.