Prof. Dr. Simon Thorpe
(University Toulouse 3, CNRS)
PGI Lecture Hall, Building 04.8, 2nd floor, Room 365
- 11.Apr.2014 11:00
Spikes and cognition
In this presentation I will argue that biological intelligence depends critically on the fact that neurons send information in the form of patterns of spikes. Firstly, sensory neurons function as analogue-to-temporal convertors, in that strong sensory inputs lead to spikes at short latencies with the result that information can be encoded as a pattern of spikes across populations of neurons. This is radically different to the conventional view that neurons represent analogue values by changing their firing rate. I will also argue that spikes are also important for learning because mechanisms involving Spike-Time Dependent Plasticity (STDP) will modify synaptic weights whenever a target neuron fires a spike. We have shown that, when a particular pattern of spikes reoccurs, STDP will naturally concentrates high synaptic weights on early firing inputs, and that this means that neurons will become selective to repeating patterns. In addition, inhibitory connections between neurons can be used to prevent different neurons learning to respond to the same patterns, resulting in a competitive learning mechanism. I will conclude by showing how this sort of mechanism can allow us to understand how the brain can store sensory memories across the entire lifespan.