Developmental Neuroscience: PDF OnlyNon-Hebbian synapses in rat visual cortexKossel, Albrecht*; Bonhoeffer, Tobias†; Bolz, Jürgen* Author Information *Friedrich-Miescher-Labor der Max-Planck-Gesellschaft, Spemannstrasse 37–39, 7400 Tübingen, FRG †Max Planck Institut für biologische Kybernetik, Spemannstrasse 38, 7400 Tübingen, FRG †The Rockefeller University, Laboratory of Neurobiology, 1230 York Avenue, New York, NY 10021, USA NeuroReport: October 1990 - Volume 1 - Issue 2 - p 115-118 Buy Abstract IN the mammalian CNS, long term potentiation can be induced by repeatedly pairing presynaptic stimulation with postsynaptic depolarization of a single cell, similar to a model proposed by Hebb, that synaptic strengthening occurs as a result of correlated pre- and postsynaptic activity. However, our experiments indicate that the Hebbian rule is not strictly valid in the cortex. Double intracellular recordings showed that synaptic reinforcement is not confined to the depolarized postsynaptic neuron, but is also observed in adjacent but not co-activated neurons. The enhancement and its spread is stimulus-specific, it occurs only for fibres stimulated during the pairing procedure. During development, this spread might lead to a characteristic organizing principle of the cortex, the clustering of cells with similar functional properties. © Lippincott-Raven Publishers.