How do correlations between V1 neurons affects information transmission and coincidence detection in the visual cortex?

F. MONTANI; A. KOHN; S. R. SCHULTZ

Brighton (UK)

Congreso; British Neuroscience Association (BNA) 2005 National Meeting Brighton; 2005

British Neuroscience Association

It has been known for many years that nearby cortical neurons tend to fire spikes that are correlated in time. This has lead some to propose that neurons may act as coincidence detectors, in addition to or rather than their well-studied role as spike integrators. We recorded from pairs of single neurons in the primary visual cortex of the anaesthetised macaque monkey. Procedures were taken to minimise pain and discomfort in accordance with local and US national guidelines. We then used information theory to evaluate the effect of correlations between V1 spike trains on the information that could be extracted from them by downstream neurons employing integration or coincidence detection strategies. Preliminary results (6 pairs of cells) indicate that correlations can influence coincidence detectors either synergistically or redundantly, but that their effect on a multinomial code (integrating spikes but preserving neuron identity) is shifted in comparison towards independence or redundancy. Pooling spikes across cells leads to a drop in information - downstream decoders benefit substantially from knowledge of cell identity. Our results suggest that while correlations may not have much effect on information transmission in the cortex, they may play a significant role in information processing tasks involving coincidence detection.