Akaysha Tang, Andreas Bartels, Terrence J. Sejnowski
Neuromodulation can change not only the mean firing rate of a neuron, but also its pattern of firing . Therefore, a reliable neu(cid:173) ral coding scheme, whether a rate coding or a spike time based coding, must be robust in a dynamic neuromodulatory environ(cid:173) ment. The common observation that cholinergic modulation leads to a reduction in spike frequency adaptation implies a modifica(cid:173) tion of spike timing, which would make a neural code based on precise spike timing difficult to maintain. In this paper, the effects of cholinergic modulation were studied to test the hypothesis that precise spike timing can serve as a reliable neural code. Using the whole cell patch-clamp technique in rat neocortical slice prepara(cid:173) tion and compartmental modeling techniques, we show that cholin(cid:173) ergic modulation, surprisingly, preserved spike timing in response to a fluctuating inputs that resembles in vivo conditions. This re(cid:173) sult suggests that in vivo spike timing may be much more resistant to changes in neuromodulator concentrations than previous physi(cid:173) ological studies have implied.
A. C. Tang, A. M. Bartels and T. J. Sejnowski