Autoradiographic localisation of substance P (NK1) receptors in human primary visual cortex

This study utilised autoradiography to examine [125I]-Bolton Hunter substance P (BHSP) binding in postmortem human visual cortex. In the primary visual area, layers I-III, IVC and VI exhibited low levels of BHSP binding, while high levels were observed in layers IVB and V. Because cells in layers IVB and V are known to be involved in processing direction-specific stimuli, it is possible that SP plays a role in modulating this visual process.