SLOW AND FAST LATERAL GENICULATE NEURONS ARE DIFFERENTLY INFLUENCED BY ACETYLCHOLINE

In rats anesthetized with urethane, potentials of 108 neurons were rec orded extracellularly in the dorsal part of the lateral geniculate bod y (dLGB). Neuronal responses to diffuse light stimuli were studied bef ore and during the iontophoretic application of acetylcholine (ACh). A lthough individual cells of all groups of functionally different neuro n types could be influenced by ACh, responses to flashes were most pro nounced and uniformly enhanced in the groups of SLOW ON-like cells loc ated in the dorsolateral and caudal parts of the dLGB. The activity in primary response phases to light flashes increased also in caudally l ocated SLOW OFF-like cells. In the group of ventromedially located FAS T OFF-like cells the postinhibitory offdischarge in the response to fl ash was significantly augmented. Only few cells of FAST ON-like groups were affected and some of them inhibited by ACh.