GABAergic excitation in the basolateral amygdala

Area of Science:

• Neuroscience
• Cellular Neuroscience
• Synaptic Plasticity

Background:

• GABAergic interneurons are traditionally known for inhibiting target neurons.
• The basolateral amygdala (BLA) plays a crucial role in emotional processing and learning.
• Understanding interneuron communication is key to deciphering neural circuit function.

Purpose of the Study:

• To investigate the functional connectivity between parvalbumin-positive interneurons in the basolateral amygdala.
• To characterize the nature of synaptic transmission evoked by single action potentials in these interneurons.
• To explore the implications of observed synaptic events for interneuron network recruitment.

Main Methods:

• Paired recordings from parvalbumin-positive interneurons in the basolateral amygdala.
• Pharmacological manipulation using antagonists for AMPA/kainate and GABA(A) receptors.
• Analysis of synaptic currents, including inhibitory and excitatory events.

Main Results:

• Single action potentials in a subpopulation of interneurons evoked both inhibitory and subsequent excitatory currents in postsynaptic interneurons.
• The excitatory component was glutamatergic and blocked by AMPA/kainate and GABA(A) receptor antagonists.
• This GABAergic excitation was observed concurrently in both pre- and postsynaptic interneurons, suggesting a novel form of excitation.
• Interneurons receiving these glutamatergic inputs showed higher probabilities of electrical coupling and bidirectional GABAergic connections.

Conclusions:

• GABAergic interneurons can mediate excitation, driving glutamatergic principal neurons to threshold.
• This provides a mechanism for both feedforward and feedback excitation within neural circuits.
• This GABAergic excitation facilitates the reliable and specific recruitment of homogeneous interneuron networks in the basal amygdala.