Acoustic processing requires integration over time. We have used in vivo intracellular recording to measure neuronal integration times in anesthetized rats. Probing with natural sounds and other stimuli, we found that context-dependent effects in the primary auditory cortex could last for surprisingly long, up to four seconds or longer in some neurons. Thalamic neurons showed only a much faster form of adaptation, indicating that the long-lasting form originated in the cortex. Restricting knowledge of the stimulus history to only a few hundred milliseconds reduced the predictable component of the response to about half of that of the optimal infinite-history model. Our results demonstrate the importance of long-range temporal effects in auditory cortex, and suggest a potential neural substrate for stream segregation and other forms of auditory processing that require integration over time scales of seconds or longer.
Poster: Computational and Systems Neuroscience (COSYNE) 2006, Salt Lake City, Utah.
Poster: Gordon Research Conference (Sensory coding and the natural environment), Big Sky, Montana, 2006.
Poster (446KB, PDF): Computational and Systems Neuroscience (COSYNE) 2007, Salt Lake City, Utah.
See also my dissertation (Chapter 3).