Interaction of Cortical and Amygdalar Synaptic Input Modulates the Window of Opportunity for Information Processing in the Rhinal Cortices

eNeuro. 2019 Aug 26;6(4):ENEURO.0020-19.2019. doi: 10.1523/ENEURO.0020-19.2019. Print Jul/Aug 2019.

Abstract

The perirhinal (PER) and lateral entorhinal (LEC) cortex function as a gateway for information transmission between (sub)cortical areas and the hippocampus. It is hypothesized that the amygdala, a key structure in emotion processing, can modulate PER-LEC neuronal activity before information enters the hippocampal memory pathway. This study determined the integration of synaptic activity evoked by simultaneous neocortical and amygdala electrical stimulation in PER-LEC deep layer principal neurons and parvalbumin (PV) interneurons in mouse brain slices. The data revealed that both deep layer PER-LEC principal neurons and PV interneurons receive synaptic input from the neocortical agranular insular cortex (AiP) and the lateral amygdala (LA). Furthermore, simultaneous stimulation of the AiP and LA never reached the firing threshold in principal neurons of the PER-LEC deep layers. PV interneurons however, mainly showed linear summation of simultaneous AiP and LA inputs and reached their firing threshold earlier. This early PV firing was reflected in the forward shift of the evoked inhibitory conductance in principal neurons, thereby creating a more precise temporal window for coincidence detection, which likely plays a crucial role in information processing.

Keywords: entorhinal cortex; parvalbumin interneurons; patch clamp; perirhinal cortex; voltage-sensitive dye imaging.

MeSH terms

  • Action Potentials
  • Amygdala / physiology*
  • Animals
  • Entorhinal Cortex / physiology*
  • Female
  • Interneurons / physiology
  • Male
  • Mice, Inbred C57BL
  • Neural Pathways / physiology
  • Neurons / physiology*
  • Perirhinal Cortex / physiology*
  • Synaptic Transmission*