Optical imaging of interaural time difference representation in rat auditory cortex.
We used in vivo voltage-sensitive dye optical imaging to examine the cortical representation of interaural time difference (ITD), which is believed to be involved in sound source localization. We found that acoustic stimuli with dissimilar ITD activate various localized domains in the auditory cortex. The main loci of the activation pattern shift up to 1 mm during the first 40 ms of the response period. We suppose that some of the neurons in each pool are sensitive to the definite ITD and involved in the transduction of information about sound source localization, based on the ITD. This assumption gives a reasonable fit to the Jeffress model in which the neural network calculates the ITD to define the direction of the sound source. Such calculation forms the basis for the cortex's ability to detect the azimuth of the sound source.
Tsytsarev
Vassiliy
V
Washington University, Department of Biomedical Engineering St Louis, MO, USA.
Fukuyama
Hidenao
H
Pope
Daniel
D
Pumbo
Elena
E
Kimura
Minoru
M