Journal ArticleDOI
GABA-containing neurons in the septum control inhibitory interneurons in the hippocampus.
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It is shown that GABA-containing afferents originating in the septum innervate most of the GABA- containing interneurons in the hippocampus, making many synaptic contacts with each of them.Abstract:
The hippocampus, in particular the neocortex-hippocampus-neocortex circuit, is widely believed to be crucial in memory. Information flow in this circuit is strongly influenced by relatively sparse afferents derived from subcortical centres, such as the septum, involved in arousal, emotions and autonomic control. A powerful mechanism, by which numerically small inputs can produce profound effects, is feed-forward inhibition, that is, the activation of local inhibitory interneurons, which, in turn, control the activity of large populations of principal cells in the hippocampus. An example is the cholinergic input to the hippocampus from the septum, which is likely to be involved in feed-forward operations. Here, we demonstrate the existence of a circuit underlying another powerful mechanism of subcortical control of hippocampal information processing. We show that GABA-containing afferents originating in the septum innervate most of the GABA-containing interneurons in the hippocampus, making many synaptic contacts with each of them. Activation of the GABA-containing neurons in the septum is likely to lead to disinhibition of the principal neurons in the hippocampal formation and so this pathway is probably crucial in the induction of hippocampal electrical activity patterns, and may be involved in NMDA (N-methyl-D-aspartate) receptor-mediated functions, such as memory, in a permissive manner.read more
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EEG alpha oscillations: The inhibition–timing hypothesis
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Theta Oscillations in the Hippocampus
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Neurophysiological and Computational Principles of Cortical Rhythms in Cognition
TL;DR: A plethora of studies will be reviewed on the involvement of long-distance neuronal coherence in cognitive functions such as multisensory integration, working memory, and selective attention, and implications of abnormal neural synchronization are discussed as they relate to mental disorders like schizophrenia and autism.
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Two-stage model of memory trace formation: a role for "noisy" brain states.
TL;DR: It is suggested that the strong excitatory drive brought about by the sharp wave-concurrent population bursts during consummatory behaviors, immobility, and slow wave sleep may be sufficient for the induction of long-term synaptic modification in the initiator neurons of the CA3 region and in their targets in CA1.
References
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TL;DR: Movement-related RSA was correlated with a decrease in firing rate of pyramidal cells and an increase in the firing of both interneurons and granule cells, and Gradual phase-shifts of RSA were observed both in CA1 and the dentate gyrus.
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Patterned stimulation at the theta frequency is optimal for the induction of hippocampal long-term potentiation.
TL;DR: The results indicate that patterns of stimulation resembling spike discharge patterns of hippocampal neurons in animals in exploratory situations are effective in inducing LTP and suggest temporal constraints on the mechanisms involved in triggering synaptic plasticity.
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Long-term potentiation and NMDA receptors in rat visual cortex
Alain Artola,Wolf Singer +1 more
TL;DR: In this article, the authors used intracellular recording techniques to show that LTP can be induced by high frequency stimulation of the optic radiation in slices of the visual cortex of adult rats.