Fig. 13.     Hypothetical circuitry between prefrontal (PFC) and specific somatosensory (S1) cortical areas via GABAergic local and projection neurons of the basal forebrain. Cholinergic and non-cholinergic neurons in the basal forebrain receive identified synaptic input from the locus coerules (LC, brown), the substantia nigra (SN, green) and the mesopontine tegmentum (PPT, blue). The projection target of these BF neurons was not determined. The innervation territory of GABAergic and cholinergic axons in the PFC and S1 are indicated schematically as non-overlapping black (GABA) and red (cholinergic) columns. The axons of pyramidal cells in the S1 cortex (hyphenated line) innervate a pyramidal neuron in the PFC. IC = inferior colliculus; LP = lateral posterior thalamic n.; ml = medial lemniscus MV = medial vestibular n.; PPT = peduculopontine tegmental n.; SC = superior colliculus; sc = superior cerebellar peduncle; VL = ventrolateral thalamic n.; VPM = ventral posteromedial n.; 7 = facial n. To prepare this drawing we used Fig. 84 from the atlas of Paxinos and Watson.¹²⁹