Midline thalamic inputs to the amygdala

Ultrastructure and synaptic targets

Alon Amir, Jean Francois Paré, Yoland Smith, Denis Pare

Research output: Contribution to journalArticle

Abstract

One of the main subcortical inputs to the basolateral nucleus of the amygdala (BL) originates from a group of dorsal thalamic nuclei located at or near the midline, mainly from the central medial (CMT), and paraventricular (PVT) nuclei. Although similarities among the responsiveness of BL, CMT, and PVT neurons to emotionally arousing stimuli suggest that these thalamic inputs exert a significant influence over BL activity, little is known about the synaptic relationships that mediate these effects. Thus, the present study used Phaseolus vulgaris-leucoagglutinin (PHAL) anterograde tracing and electron microscopy to shed light on the ultrastructural properties and synaptic targets of CMT and PVT axon terminals in the rat BL. Virtually all PHAL-positive CMT and PVT axon terminals formed asymmetric synapses. Although CMT and PVT axon terminals generally contacted dendritic spines, a substantial number ended on dendritic shafts. To determine whether these dendritic shafts belonged to principal or local-circuit cells, calcium/calmodulin-dependent protein kinase II (CAMKIIα) immunoreactivity was used as a selective marker of principal BL neurons. In most cases, dendritic shafts postsynaptic to PHAL-labeled CMT and PVT terminals were immunopositive for CaMKIIα. Overall, these results suggest that CMT and PVT inputs mostly target principal BL neurons such that when CMT or PVT neurons fire, little feed-forward inhibition counters their excitatory influence over principal cells. These results are consistent with the possibility that CMT and PVT inputs constitute major determinants of BL activity.

Original languageEnglish (US)
Pages (from-to)942-956
Number of pages15
JournalJournal of Comparative Neurology
Volume527
Issue number5
DOIs
StatePublished - Apr 1 2019

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Amygdala
Calcium-Calmodulin-Dependent Protein Kinase Type 2
Presynaptic Terminals
Neurons
Intralaminar Thalamic Nuclei
Thalamic Nuclei
Dendritic Spines
Calcium-Calmodulin-Dependent Protein Kinases
Paraventricular Hypothalamic Nucleus
Synapses
Electron Microscopy
plants leukoagglutinins

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

Keywords

  • CAMKIIα
  • RRID AB_2313606
  • RRID AB_2313686
  • RRID AB_2336656
  • RRID AB_2637031
  • RRID AB_447192
  • RRID RGD_734476
  • amygdala
  • electron microscopy
  • thalamus
  • tract-tracing

Cite this

Amir, Alon ; Paré, Jean Francois ; Smith, Yoland ; Pare, Denis. / Midline thalamic inputs to the amygdala : Ultrastructure and synaptic targets. In: Journal of Comparative Neurology. 2019 ; Vol. 527, No. 5. pp. 942-956.
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Midline thalamic inputs to the amygdala : Ultrastructure and synaptic targets. / Amir, Alon; Paré, Jean Francois; Smith, Yoland; Pare, Denis.

In: Journal of Comparative Neurology, Vol. 527, No. 5, 01.04.2019, p. 942-956.

Research output: Contribution to journalArticle

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T1 - Midline thalamic inputs to the amygdala

T2 - Ultrastructure and synaptic targets

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AU - Paré, Jean Francois

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