Marco Capogna

Synaptic heterogeneity between mouse paracapsular intercalated neurons of the amygdala

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • Raffaella Geracitano, MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK. Electronic address: marco.capogna@pharm.ox.ac.uk.
  • ,
  • Walter A Kaufmann
  • ,
  • Gabor Szabo
  • ,
  • Francesco Ferraguti
  • ,
  • Marco Capogna

GABAergic medial paracapsular intercalated (Imp) neurons of amygdala are thought of as playing a central role in fear learning and extinction. We report here that the synaptic network formed by these neurons exhibits distinct short-term plastic synaptic responses. The success rate of synaptic events evoked at a frequency range of 0.1-10 Hz varied dramatically between different connected cell pairs. Upon enhancing the frequency of stimulation, the success rate increased, decreased or remained constant, in a similar number of cell pairs. Such synaptic heterogeneity resulted in inhibition of the firing of the postsynaptic neurons with different efficacies. Moreover, we found that the different synaptic weights were mainly determined by diversity in presynaptic release probabilities rather than postsynaptic changes. Sequential paired recording experiments demonstrated that the same presynaptic neuron established the same type of synaptic connections with different postsynaptic neurons, suggesting the absence of target-cell specificity. Conversely, the same postsynaptic neuron was contacted by different types of synaptic connections formed by different presynaptic neurons. A detailed anatomical analysis of the recorded neurons revealed discrete and unexpected peculiarities in the dendritic and axonal patterns of different cell pairs. In contrast, several intrinsic electrophysiological responses were homogeneous among neurons, and synaptic failure counts were not affected by presynaptic cannabinoid 1 or GABA B receptors. We propose that the heterogeneous functional connectivity of Imp neurons, demonstrated by this study, is required to maintain the stability of firing patterns which is critical for the computational role of the amygdala in fear learning and extinction.

Original languageEnglish
JournalThe Journal of Physiology
Volume585
IssuePt 1
Pages (from-to)117-34
Number of pages18
ISSN0022-3751
DOIs
Publication statusPublished - 15 Nov 2007

    Research areas

  • Amygdala/cytology, Animals, Electrophysiology, Green Fluorescent Proteins/genetics, Interneurons/physiology, Mice, Mice, Transgenic, Patch-Clamp Techniques, Presynaptic Terminals/physiology, Receptor, Cannabinoid, CB1/physiology, Receptors, GABA-B/physiology, Synapses/physiology, Synaptic Transmission/physiology

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