Sample size dependence of estimation error of information carried by neuronal spike train

The operating performance of a neural system should be represented by the amount of information carried by neurons. The neuron behaves as a pulse encoder, which converts a stimulus waveform into a discrete pulse (spike) train. In practice, the rate of information transmission is estimated on the basis of a finite number of spikes obtained in a finite observation period. Consequently, the result includes an error. This paper considers the case in which the rate of information transmission is derived from the stimulus–response coherence, and analyzes the relation between the estimation error and the sample size (total number of spikes). It is found that the estimation error of information carried by a single spike is inversely proportional to the total number of spikes used for the estimation. It is pointed out that the asymptotic value of inverse proportion should be used for the comparison of information obtained from different neurons. The validity of the relation between the number of samples and the information per spike is verified by using data obtained from the cricket cercal sensory cells. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(7): 84–95, 2005; Published online in Wiley InterScience (). DOI 10.1002sscj.10420