Auditory cortex adaptation decreases response to frequent sounds, shaping perception

Evidence

Spectral adaptation may also be caused, at least partly, by central brain processes. Adaptation in the central hearing system appears to be stronger and to have a longer time constant (Holt, 2006; Ulanovsky et al., 2003, 2004; Watkins, 1991). This effect is assumed to occur at the level of the auditory cortex, and it is called stimulus-specific adaptation, which is the specific decrease in the response to a frequent (standard) stimulus (Holt, 2006). In addition, such adaptation may also occur at even higher stages in the brain in the cognitive processes. This would mean subconscious calculation of the average spectrum and its inverse filtering during listening. Adaptation may also be inextricably linked to auditory memory, whereby adaptation occurs by a process of forgetting (McKeown and Wellsted, 2009). These adaptation effects are relatively poorly understood. The time constants in peripheral adaptation and central adaptation are not yet confirmed, and the mechanisms behind adaptation are largely unknown. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1254

Categorization

• DEFINE: Defines stimulus-specific adaptation (SSA), the cortical decrease in response to standard repeated stimuli - a key concept distinguishing peripheral from central auditory adaptation.
• QUESTION: The idea that adaptation is ‘a process of forgetting’ is nearly the inverse of standard models (adaptation as fatigue). Worth chasing the McKeown-Wellsted argument.