title: Amygdala input to medial prefrontal cortex (mPFC) in the rat: a light and electron microscope study.
abstract: This paper describes the termination pattern and synaptic connectivity of the pathway from the basolateral nucleus of the amygdala (BLA) to the medial prefrontal cortex (mPFC; areas 25, 32, and 24b) of the rat. Discrete injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) were made in the BLA and detailed light microscopical observations made of the distribution of PHA-L labelled fibres and boutons in the mPFC. Labelled fibres were distributed in two tiers: predominantly within deep layer 1/layer 2 and also in layers 5/6. Fibre plexi in layers 2 and 5 were highly varicose. Electron microscopical examination of 120 labelled boutons in area 32 (60 in layer 2 and 60 in layer 5) indicated that 116 (97%) established asymmetrical synaptic contacts with dendritic spines and 4 (3%) were in synaptic contact with small dendritic shafts. No significant differences in target structures were found between layers 2 and 5. The results indicate that BLA input to mPFC in the rat predominantly innervates spine bearing dendrites in layers 2 and 5. This suggests that the neuronal operations of these processes are influenced by direct feedforward excitation from the BLA.
authors.affiliation: University Department of Pharmacology, Oxford, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Bacon
authors.forename: A J
authors.initials: AJ
authors.lastname: Headlam
authors.forename: P L
authors.initials: PL
authors.lastname: Gabbott
authors.forename: A D
authors.initials: AD
authors.lastname: Smith
mesh_terms: D000344:Afferent Pathways / Q000502:physiology / Q000648:ultrastructure; D000679:Amygdala / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D003712:Dendrites / Q000502:physiology / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D010835:Phytohemagglutinins; D017397:Prefrontal Cortex / Q000502:physiology* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure
chemical_list: D010835:Phytohemagglutinins; C100156:leukoagglutinins, plants