Statistical and information properties of head direction cells

The human channel capacity for identifying sensory stimuli is compared with channel capacities based on neurophysiological findings. Studies have show n that cells in the postsubiculum. (PoS) and the anterior dorsal thalamus ( ADN) of the rat discharge as a function of the animal's head direction in t he horizontal plane. We compute the statistical properties of the firing ra tes of head direction (HD) cells and the potential amount of information tr ansmitted by these cells according to two theoretical models. The cell resp onse model for single cells indicates that information transmitted is much less than 0.5 bits. The population response model developed for cell ensemb les generates values in the range of 1-3.2 bits, suggesting that a cell pop ulation can distinguish between two and nine head directions, depending on the value used for the standard deviation of directions over which a cell f ires. These values are similar to those found in human psychophysical studi es of the channel capacity for unidimensional sensory attributes.