Abstract
Sensory information is processed in multiple cortical areas, which are connected with the pathways in the white matter. However, adjacent areas are also connected with direct pathways via the cortical boundary between them. To elucidate the roles of latter pathways, we investigated the functional connections via the boundary between the primary auditory cortex (area 41) and the surrounding areas in rat cortical slices. Neural activities were elicited by repetitive stimulation at 20 Hz for 1 s applied at layer V, and the propagating activities via the cortical boundaries were visualized using flavoprotein autofluorescence imaging method. The neural activities propagating in a short range (~0.5 mm) between area 41 and anterior area 39, or area 41 and dorsal area 18a spread around the boundary almost symmetrically. But the activities from area 41 into the secondary auditory cortices (ventral area 20 and posterior area 36) were more prominent than those in the opposite direction. This asymmetry was also observed in the activities propagating in a long range (~1.5 mm) between area 20 and the middle part of area 41. The application of 10 μM CNQX, an antagonist of non-NMDA glutamate receptor, suppressed the long-range propagation of neural activities, while cutting the white matter around the cortical boundary had no effect. Now we are investigating the possibility that these functional connections between areas might be modified by sensory deprivation in the slices obtained from deafened rats. [Jpn J Physiol 54 Suppl:S145 (2004)]
