Stimulus-induced up states in the dorsal pallium of a weakly electric fish.

We investigated the response of putative novelty-detecting neurons in the pallium of an electric fish to electrosensory and acoustic stimuli. Extracellular and whole cell patch recordings were made from neurons in the dorsal pallial nucleus (DD) of Apteronotus leptorhynchus. DD neurons were typically quiescent and exhibited hyperpolarized resting membrane potentials. Stimulation induced, with a variable long latency, rapid though transient depolarization and spike discharge. The transition between resting and depolarized/spiking states resembled the transition to Up states seen in mammalian telencephalic neurons.