parvalbuminpositive

Parvalbumin-positive, often abbreviated PV+, refers to cells that express the calcium-binding protein parvalbumin. Parvalbumin is a small EF-hand protein that buffers intracellular calcium and shapes calcium transients during neural activity. In neuroscience, PV+ is used to label a distinct class of fast-spiking GABAergic interneurons.

PV+ interneurons include basket cells and chandelier cells, widely distributed in cortex, hippocampus, and other brain regions. They are characterized by high firing rates, little spike-frequency adaptation, and perisomatic inhibition of pyramidal neurons, which enables precise control of output timing and synchronization, particularly in gamma-frequency ranges. Their fast signaling relies on specialized voltage-gated potassium channels (e.g., Kv3 family).

Identification and development: Parvalbumin expression develops postnatally in many species. PV+ neurons are commonly identified by immunohistochemistry against parvalbumin or by genetic reporter lines that drive expression under the Pvalb promoter. They typically co-express GABA synthesis enzymes (GAD65/67) as inhibitory neurons.

Functional and clinical relevance: PV+ interneurons regulate cortical and hippocampal networks, shaping perception, attention, and memory through timing and synchronization. Alterations in PV+ cell function or PV expression have been observed in several disorders, including schizophrenia, autism spectrum disorders, epilepsy, and neurodegenerative diseases. Changes may involve reduced PV expression, altered connectivity, or impaired gamma oscillations.

Notes: PV labeling marks a functional subclass rather than a single cell type; PV+ neurons are heterogeneous across brain regions and species. While PV is a robust marker, its expression can be modulated by activity, development, and disease, so interpretation should consider context.