Figure 6.

Coronal sections through the medial geniculate body (MGB) that have been stained for cytochrome oxidase activity. High enzyme activity occurs in the anterior pretectal nucleus (APT) and in the ventral (V) division of the MGB while relatively low levels occur in the lateroposterior (LP) nucleus and shell division of the MGB. The dorsal division (D) of the MGB has intermediate enzyme activity while the medial division (M) of the MGB has a striated appearance because of bundles of fibers. (A) A single electrode track (small white arrows) filled with darkly stained red blood corpuscles terminates in an electrolytic lesion (white arrowhead) at the medial edge of the ventral MGB. The edge of another electrolytic lesion is slightly more lateral but the track associated with this lesion cannot be seen in this section. The CF of the unit recorded at the medial lesion was 0.55 kHz while the CF of the more lateral lesion was 1.4 kHz. (B) The pale line of damaged tissue indicating an electrode track (white arrows) ends in an electrolytic lesion (arrowhead) in the medial division. The CF of the unit at the lesion was 1.5 kHz.