SK channels provide a novel mechanism for the control of frequency tuning in electrosensory neurons.
One important characteristic of sensory input is frequency, with sensory neurons often tuned to narrow stimulus frequency ranges. Although vital for many neural computations, the cellular basis of such frequency tuning remains mostly unknown. In the electrosensory system of Apteronotus leptorhynchus, the primary processing of important environmental and communication signals occurs in pyramidal neurons of the electrosensory lateral line lobe. Spike trains transmitted by these cells can encode low-frequency prey stimuli with bursts of spikes and high-frequency communication signals with single spikes. Here, we demonstrate that the selective expression of SK2 channels in a subset of pyramidal neurons reduces their response to low-frequency stimuli by opposing their burst responses. Apamin block of the SK2 current in this subset of cells induced bursting and increased their response to low-frequency inputs. SK channel expression thus provides an intrinsic mechanism that predisposes a neuron to respond to higher frequencies and thus specific, behaviorally relevant stimuli.
Ellis
Lee D
LD
Center for Research in Neuroscience and Department of Biology, McGill University, Montreal, Quebec, Canada H3G 1A4.
Mehaffey
W Hamish
WH
Harvey-Girard
Erik
E
Turner
Ray W
RW
Maler
Leonard
L
Dunn
Robert J
RJ
D000200:Action Potentials / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D001921:Brain / Q000166:cytology* / Q000502:physiology; D004555:Electric Fish / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods; D015870:Gene Expression; D017403:In Situ Hybridization / Q000379:methods; D066298:In Vitro Techniques; D009475:Neurons, Afferent / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology*; D016415:Sequence Alignment / Q000379:methods; D051640:Small-Conductance Calcium-Activated Potassium Channels / Q000502:physiology*
D051640:Small-Conductance Calcium-Activated Potassium Channels; D001030:Apamin