Effects of noise correlations on information encoding and decoding.
Response variability is often correlated across populations of neurons, and these noise correlations may play a role in information coding. In previous studies, this possibility has been examined from the encoding and decoding perspectives. Here we used d prime and related information measures to examine how studies of noise correlations from these two perspectives are related. We found that for a pair of neurons, the effect of noise correlations on information decoding can be zero when the effect of noise correlations on the information encoded obtains its largest positive or negative values. Furthermore, there can be no effect of noise correlations on the information encoded when it has an effect on information decoding. We also measured the effect of noise correlations on information encoding and decoding in simultaneously recorded neurons in the supplementary motor area to see how well d prime accounted for the information actually present in the neural responses and to see how noise correlations affected encoding and decoding in real data. These analyses showed that d prime provides an accurate measure of information encoding and decoding in our population of neurons. We also found that the effect of noise correlations on information encoding was somewhat larger than the effect of noise correlations on information decoding, but both were relatively small. Finally, as predicted theoretically, the effects of correlations were slightly greater for larger ensembles (3-8 neurons) than for pairs of neurons.
Department of Brain and Cognitive Sciences, Center for Visual Science, University of Rochester, Rochester, New York 14627, USA. baverbeck@cvs.rochester.edu
Bruno B
BB
Averbeck
Daeyeol
D
Lee
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003198:Computer Simulation; D003213:Conditioning, Psychological / Q000502:physiology; D016247:Information Storage and Retrieval / Q000379:methods*; D008253:Macaca mulatta; D008297:Male; D008959:Models, Neurological; D015233:Models, Statistical; D009044:Motor Cortex / Q000166:cytology / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013223:Statistics as Topic; D013269:Stochastic Processes; D009435:Synaptic Transmission / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology