Draft:Fast-spiking Parvalbumin Positive GABAergic Interneurons

Fast-spiking Parvalbumin Positive GABAergic Interneurons (sometimes refered to as PV+ interneurons) are a subset of interneurons that feature distinct fast-spiking electrophysiological properties and are typically identified based on expression of the calcium-binding protein parvalbumin

Anatomy
Their morphology typically falls into either the subcategory of basket cells or chandelier cells and are commonly ensheathed in perineuronal nets, although delineation of interneuron subtypes is a developing field

Network Activity
PV+ Interneurons play significant roles in many aspects of network activity such as feedforward inhibition, feedback inhibition, network oscillations, and regulation of plasticity

This type of cells receives the greatest amount of excitatory input of any inhibitory neuron in the cortex, and they powerfully regulate local pyramidal cell network activity

During gamma-oscillations the metabolic demand on PV+ interneurons is similar to that observed in seizure-like events, suggesting that during heightened activity this cell type is prone to metabolic disruption

Perineuronal Nets
Supporting structures such as the specialized ECM structure perineuronal nets (PNNs) preferentially wrap around PV+ interneurons to support their fast-spiking properties by providing a cation rich environment, reducing membrance capacitance and buffering them against metabolic stress

Critical Period Regulation
The developmental trajectory of PV+ interneurons and the supporting PNNs that wrap around them coincides with critical period opening and closure, with maturation of the PV+ interneurons and the PNNs marking the closure of the critical period.

Treatment with NMDA receptor antagonist such as ketamine, PCP, or MK-801 that disrupt the NMDAR-mediated input to PV+ Interneurons have the potential to modulate critical period plasticity