Parvalbumin-immunoreactive neurons in the human anteroventral thalamic nucleus

We immunohistochemically characterised the expression of the calcium-binding protein parvalbumin in the normal human anteroventral thalamic nucleus (AVN). Two morphologically distinct neuronal populations were found to be parvalbumin-immunoreactive (PV-IR): a large population of lightly staining PV-IR neurons and a smaller population of intensely PV-IR neurons. This second type of neuron, which displayed many characteristics normally associated with GABAergic interneurons, has not previously been described in human thalamus. Thus, presumptive thalamic interneurons in the human brain can be further subtyped on the basis of immunoreactivity to parvalbumin. This may have implications for the understanding of thalamocortical function in the normal state and in dysfunctional conditions such as Wernicke-Korsakoff syndrome and schizophrenia.