Fluorescent latex microspheres for retrograde tracing of neurons in mouse basal forebrain combined with immunocytochemistry: a methodical approach.

The presented methodical contribution demonstrates the suitability of rhodamine-labelled latex microspheres with a defined mean diameter of around 20 nm for retrograde neuronal tracing. After small injections of about 200 nl red fluorescent tracer into visual cortex of mice afferent neurons were labelled in cortical and subcortical structures. Basal forebrain neurons containing the tracer were further characterized by the concurrent visualization of choline acetyltransferase, a marker for cholinergic neurons, and parvalbumin, a putative marker of GABAergic neurons, by immunofluorescence.