Figure 2.

Distribution of cholinergic receptors across cortical regions in primate and their physiological functions. Studies in primate have shown unique patterns of receptor expression for both nicotinic and muscarinic cholinergic receptors between cortical areas. (A) In V1 muscarinic receptors are expressed by GABAergic cells (M1 and M2) or presynaptically (M2), and nicotinic β2-containing receptors are predominantly expressed presynaptically on thalamocortical terminals. Nicotinic α7 receptors are also expressed in V1 but their precise localization is still unclear. (B) In area MT, M1 receptors are expressed by both GABAergic cells and the majority of excitatory pyramidal cells. (C) In layer III of dlPFC, NMDAR-NR2B are found within the PSD of glutamate spine synapses. Muscarinic receptors are found within or near the PSD on spines (M1) or presynaptically on presumed ACh terminals (M2). Nicotinic α7 receptors are also found within or near the PSD on spines in primate layer III dlPFC. The specific distribution pattern of α4β2 receptors in primate PFC is unknown. (D) The effect of nicotinic receptor activation in monkey and tree shrew V1, based on data from Disney et al. (2007) and Bhattacharyya et al. (2012), showing that activation of nicotinic receptors significantly increases gain response in layer IV, but not in other layers. (E) Data from dlPFC based on Yang et al. (2013) showing that nicotinic α7 receptor stimulation enhances Delay cell persistent firing at optimal doses. See text for more details.