CONVERGENCE of PROJECTIONS FROM the RAT HIPPOCAMPAL-FORMATION, MEDIAL GENICULATE and BASAL FOREBRAIN ONTO SINGLE AMYGDALOID NEURONS - AN INVIVO EXTRACELLULAR and INTRACELLULAR ELECTROPHYSIOLOGICAL STUDY

CONVERGENCE of PROJECTIONS FROM the RAT HIPPOCAMPAL-FORMATION, MEDIAL GENICULATE and BASAL FOREBRAIN ONTO SINGLE AMYGDALOID NEURONS - AN INVIVO EXTRACELLULAR and INTRACELLULAR ELECTROPHYSIOLOGICAL STUDY

Author Mello, LEAM Google Scholar
Tan, A. M. Google Scholar
Finch, D. M. Google Scholar
Institution UNIV CALIF LOS ANGELES
Universidade Federal de São Paulo (UNIFESP)
Abstract We recorded extra- and intracellular responses from rat amygdaloid neurons in vivo after electrical stimulation of the hippocampal formation (dentate gyrus, hippocampal fields CA3 and CA4, entorhinal cortex, subicular complex); medial geniculate; and basal forebrain (diagonal band, ventral pallidum, olfactory tubercle, nucleus accumbens, bed nucleus of stria terminalis, lateral preoptic area, substantia innominata). Stimulation of hippocampal formation structures evoked IPSPs or EPSP-IPSP sequences in which the IPSP had a lower threshold than the EPSP. Recordings from candidate inhibitory neurons in the amygdala indicated that excitatory afferents from the hippocampal formation contact both amygdaloid inhibitory and principal neurons (feedforward inhibition), and that the inhibitory neurons have a lower threshold of activation. Medial geniculate stimulation also evoked EPSP-IPSP sequences. in marked contrast to these results, stimulation of basal forebrain structures evoked short latency IPSPs in amygdaloid neurons. This provides the first physiological evidence for direct inhibition of the amygdala by the basal forebrain. Basal forebrain stimulation also evoked EPSP-IPSP sequences in amygdaloid neurons. Individual amygdaloid neurons could show responses to stimulation of the hippocampal formation, basal forebrain, and medial geniculate, indicating that synaptic input from these areas converges onto single amygdaloid cells. the findings provide further information about the synaptic organization of afferents to the amygdala, and indicate that single amygdaloid neurons play a role in the synaptic integration of input from these diverse sources.
Keywords LIMBIC SYSTEM
INHIBITORY NEURON
NEURAL NETWORK
DIAGONAL BAND
VENTRAL PALLIDUM
SUBSTANTIA INNOMINATA
SUBICULAR COMPLEX
ENTORHINAL CORTEX
Language English
Date 1992-07-31
Published in Brain Research. Amsterdam: Elsevier B.V., v. 587, n. 1, p. 24-40, 1992.
ISSN 0006-8993 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 24-40
Origin http://dx.doi.org/10.1016/0006-8993(92)91425-E
Access rights Closed access
Type Article
Web of Science ID WOS:A1992JK14000003
URI http://repositorio.unifesp.br/handle/11600/25267

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