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The effects of stimulation of substantia innominata and sensory receiving areas of the forebrain upon the activity of neurons within the amygdala of the anesthetized cat
- Source :
- Brain Research. 269:119-132
- Publication Year :
- 1983
- Publisher :
- Elsevier BV, 1983.
-
Abstract
- The present study investigated the response characteristics of individual neurons in the amygdala following stimulation of the substantia innominata (SI), and compared these responses with those elicited by stimulation of insular and temporal polar cortices and the lateral olfactory tract (LOT). Recordings were made from single units within the medial, central, basal, and lateral amygdaloid nuclei of anesthetized, male cats. Stimulating electrodes were located in the SI, LOT, and sylvian cortex (SG). Unit responses were classified as either excitation or inhibition. Excitatory responses were further divided into fixed latency excitation (FLE) and variable latency excitation (VLE) based on the variability of the onset latency of the response. The majority of responses to SI stimulation were of the FLE type, implying a direct orthodromic, monosynaptic activation of amygdaloid units. Proportionally more FLE responses were recorded laterally, especially in the magnocellular basal nucleus, compared to VLE responses which were common in the medial and central nuclei. SI stimulation consistently affected the activity of many more units than did SG or LOT stimulation. The onset latencies of the population of cells exhibiting excitatory responses elicited by SI stimulation were distributed bimodally, and this may reflect a dual projection pathway of amygdaloid afferents from this basal forebrain region. This correlates with anatomical descriptions indicating that SI projections to amygdala pass via the ventral amygdalofugal pathway as well as in the stria terminalis. Excitatory onset latencies of responses to SI stimulation were the shortest in the lateral and magnocellular basal nuclei and the longest in the parvocellular basal nucleus. Amygdaloid units exhibited convergent input from the stimulus sites. A clear topographical distribution of units was not demonstrated. The data suggests that units receiving a convergent input were rarely driven monosynaptically by more than one stimulus site. The basal nucleus contained the smallest fraction of units exhibiting a convergent input. A small population of antidromic responses was recorded and indicates that within the system studied the caudal aspect of the basal nucleus is a major source of amygdaloid efferents. Antidromically driven units did not exhibit transynaptic responses following stimulation of any of the test sites.
- Subjects :
- Male
Hypothalamus
Sensation
Stimulation
Biology
Synaptic Transmission
Amygdalofugal pathway
Parvocellular cell
Reaction Time
medicine
Animals
Evoked Potentials
Molecular Biology
Cerebral Cortex
Neurons
Temporal cortex
Afferent Pathways
Brain Mapping
Basal forebrain
General Neuroscience
Substantia innominata
Brain
Neural Inhibition
Olfactory Pathways
Anatomy
Amygdala
Electric Stimulation
Temporal Lobe
Antidromic
Stria terminalis
medicine.anatomical_structure
nervous system
Cats
Neurology (clinical)
Neuroscience
Developmental Biology
Subjects
Details
- ISSN :
- 00068993
- Volume :
- 269
- Database :
- OpenAIRE
- Journal :
- Brain Research
- Accession number :
- edsair.doi.dedup.....c7585d600f4a9a8f7ec9bf88ff9e4f9d
- Full Text :
- https://doi.org/10.1016/0006-8993(83)90968-x