Context-Dependent Processing in Auditory Cortex
Context-dependent processing refers to the experimental finding that a neuron may respond to the same stimulus in different ways, depending on the recent history of the stimulation. Context dependence differs from plasticity in that the changes in response properties are fast and reversible.
Responses in the auditory system are context dependent at multiple time scales. Already at the level of the auditory nerve, firing rate adaptation constitutes a simple form of context dependence, although the times involved are mostly on the order of a few ms up to a few tens of ms (Eggermont 1985). A major example of context dependence consists of the suppression of the responses to a stimulus that is preceded shortly beforehand by another similar stimulus (often called “forward masking”). Forward masking at the level of the mechanical vibrations of the cochlea may account for most properties of psychoacoustical forward masking (Plack and Oxenham 1998). At the...