Long term potentiation in the magnocellular medial geniculate nucleus of the anesthetized cat

Long term potentiation (LTP) has been suggested as a mechanism in learning. The magnocellular division of the medial geniculate nucleus (MGm) is known to develop discharge plasticity rapidly during behavioral learning. The ability of the MGm also to develop long term potentiation was studied in cats under barbiturate anesthesia. Monosynaptic responses elicited in the MGm by periodic (0.2 Hz) stimulation of the brachium of the inferior colliculus (BIC) developed significant increases in amplitude and decreases in latency, which were maintained for at least 1 h, following brief high frequency stimulation of the BIC. Antidromic responses recorded in the inferior colliculus were unchanged. These findings provide a link between learning-induced physiological plasticity and LTP, and demonstrate that the auditory system can develop long term potentiation.