title: Laminar- and Target-Specific Amygdalar Inputs in Rat Primary Gustatory Cortex.
abstract: The primary gustatory cortex (GC) receives projections from the basolateral nucleus of the amygdala (BLA). Behavioral and electrophysiological studies demonstrated that this projection is involved in encoding the hedonic value of taste and is a source of anticipatory activity in GC. Anatomically, this projection is largest in the agranular portion of GC; however, its synaptic targets and synaptic properties are currently unknown. In vivo electrophysiological recordings report conflicting evidence about BLA afferents either selectively activating excitatory neurons or driving a compound response consistent with the activation of inhibitory circuits. Here we demonstrate that BLA afferents directly activate excitatory neurons and two distinct populations of inhibitory neurons in both superficial and deep layers of rat GC. BLA afferents recruit different proportions of excitatory and inhibitory neurons and show distinct patterns of circuit activation in the superficial and deep layers of GC. These results provide the first circuit-level analysis of BLA inputs to a sensory area. Laminar- and target-specific differences of BLA inputs likely explain the complexity of amygdalocortical interactions during sensory processing.
  
  
  CONCLUSIONS
  Projections from the basolateral nucleus of the amygdala (BLA) to the cortex convey information about the emotional value and the expectation of a sensory stimulus. Although much work has been done to establish the behavioral role of BLA inputs to sensory cortices, very little is known about the circuit organization of BLA projections. Here we provide the first in-depth analysis of connectivity and synaptic properties of the BLA input to the gustatory cortex. We show that BLA afferents activate excitatory and inhibitory circuits in a layer-specific and pattern-specific manner. Our results provide important new information about how neural circuits establishing the hedonic value of sensory stimuli and driving anticipatory behaviors are organized at the synaptic level.
authors.affiliation: Department of Neurobiology and Behavior and Program in Neuroscience, State University of New York-Stony Brook, Stony Brook, New York 11794.
authors.forename: Melissa S
authors.identifier: http://orcid.org/0000-0002-6018-2809
authors.initials: MS
authors.lastname: Haley
authors.affiliation: Department of Neurobiology and Behavior and Program in Neuroscience, State University of New York-Stony Brook, Stony Brook, New York 11794 Alfredo.fontanini@stonybrook.edu Arianna.maffei@stonybrook.edu.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Fontanini
authors.affiliation: Department of Neurobiology and Behavior and Program in Neuroscience, State University of New York-Stony Brook, Stony Brook, New York 11794 Alfredo.fontanini@stonybrook.edu Arianna.maffei@stonybrook.edu.
authors.forename: Arianna
authors.identifier: http://orcid.org/0000-0001-6755-8904
authors.initials: A
authors.lastname: Maffei
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000235:genetics; D000344:Afferent Pathways / Q000502:physiology*; D000679:Amygdala / Q000502:physiology*; D000818:Animals; D000075402:Channelrhodopsins; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005260:Female; D008297:Male; D009433:Neural Inhibition / Q000502:physiology; D010320:Parvalbumins / Q000378:metabolism; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D066191:Sensorimotor Cortex / Q000166:cytology*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013649:Taste / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D000075402:Channelrhodopsins; D018691:Excitatory Amino Acid Antagonists; D010320:Parvalbumins; D026902:Potassium Channel Blockers; D011810:Quinoxalines; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; C056723:FG 9041; D015761:4-Aminopyridine
keywords: basolateral amygdala; excitation; gustatory cortex; inhibition; microcircuitry; optogenetics