Spike-frequency adaptation generates intensity invariance in a primary auditory interneuron

Adaptation of the spike-frequency response to constant stimulation, as observed on various timescales in many neurons, reflects high-pass filter properties of a neuron's transfer function. Adaptation in general, however, is not sufficient to make a neuron's response independent of the mean intensity of a sensory stimulus, since low frequency components of the stimulus are still transmitted, although with reduced gain. We here show, based on an analytically tractable model, that the response of a neuron is intensity invariant, if the fully adapted steady-state spike-frequency response to constant stimuli is independent of stimulus intensity. Electrophysiological recordings from the AN1, a primary auditory interneuron of crickets, show that for intensities above 60 dB SPL (sound pressure level) the AN1 adapted with a time-constant of 40 ms to a steady-state firing rate of 100 Hz. Using identical random amplitude-modulation stimuli we verified that the AN1's spike-freque...

• Type: Journal
• Year: 2008
• Where: JCNS
• Authors: Jan Benda, Matthias Hennig
• Keywords: JCNS 2008, Mean Intensity, Spike-frequency Response, Transfer Function