title: Amygdala input monosynaptically innervates parvalbumin immunoreactive local circuit neurons in rat medial prefrontal cortex.
abstract: The projection from the basolateral nucleus of the amygdala (BLA) conveys information about the affective significance of sensory stimuli to the medial prefrontal cortex (mPFC). By using an anterograde tract-tracing procedure combined with immunocytochemistry and correlated light/electron microscopical examination, labeled BLA afferents to layers 2-6 of the rat mPFC are shown to establish asymmetrical synaptic contacts, not only with dendritic spines (approximately 95.7% of targets innervated), but also with the aspiny dendritic shafts and somata of multipolar parvalbumin immunopositive (PV+) neurons. A population of PV- dendritic shafts was also innervated. Labeled BLA synaptic input to identified PV+ structures occurred in layers 2-6 of mPFC. The results indicate that labeled BLA afferents predominantly contact the spiny processes of presumed pyramidal cells and also provide a direct and specific innervation to a sub-population of local circuit neurons in mPFC containing PV. Since PV+ cells include two significant classes of fast-spiking GABAergic inhibitory interneuron (basket and axo-axonic cells), these novel observations indicate that the amygdalocortical pathway in the rat has the ability to directly influence functionally strategic 'feed-forward' inhibitory mechanisms at the first stage of processing amygdalocortical information.
authors.affiliation: Department of Biological Sciences, The Open University, Milton Keynes MK7 6AA, UK. p.l.gabbott@open.ac.uk
authors.forename: P L A
authors.initials: PL
authors.lastname: Gabbott
authors.forename: T A
authors.initials: TA
authors.lastname: Warner
authors.forename: S J
authors.initials: SJ
authors.lastname: Busby
mesh_terms: D000344:Afferent Pathways / Q000166:cytology* / Q000378:metabolism; D000679:Amygdala / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D007150:Immunohistochemistry; D008297:Male; D046529:Microscopy, Electron, Transmission; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism*; D017397:Prefrontal Cortex / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D010320:Parvalbumins