Abstract
We have reported that exposure to environmental sounds induces neural potentiation in the auditory cortex using transcranial flavoprotein autofluorescence imaging in the mouse auditory cortex in vivo. However, the location of targets for the effect of acoustic environment is unknown. To elucidate possible involvement of intracortical circuits in the potentiation, we reared C57BL/6 mice in a sound proof room with or without exposure to environmental sound stimuli at 10 kHz for several weeks, and cortical slices including the auditory cortex were prepared from the mice. Cortical images of green autofluorescence of flavoproteins in blue light were recorded. To evaluate the function of intracortical circuits, repetitive electrical stimulation at 10 Hz for 0.5 s was applied to supragranular layers in the auditory cortex, and the resulting horizontal spreading of cortical activities were evaluated with autofluorescence imaging. The size of the response areas in the mice exposed to environmental sound stimuli was significantly larger than that in the mice not exposed to sound stimuli. The present results confirm the previous results that acoustic environments are required for the development of neural activities in the auditory cortex in vivo. Furthermore, it is clearly demonstrated that intracortical circuits are one of the responsive sites for the effect of acoustic environment. [Jpn J Physiol 55 Suppl:S153 (2005)]
