Laminar distributions of neurons sensitive to acetylcholine, noradrenaline and dopamine in the dorsolateral prefrontal cortex of the monkey.
Sensitivities of neurons to acetylcholine (ACh), noradrenaline (NA) and dopamine (DA) were investigated at different depths of the dorsolateral prefrontal cortex (PFC) in awake or halothane-anesthetized macaque monkeys, using microiontophoretic techniques with multi-barreled electrodes. The laminar locations of tested neurons (n = 403) were estimated by reconstructing electrode tracks based on the microlesion made by passing a current through the recording barrel, which contained a carbon fiber. Iontophoretically applied drugs induced excitatory or inhibitory responses. Neurons excited by ACh (n = 105) were located mainly in layers III and V, and those inhibited by ACh (n = 126) were in layers III and IV. The majority of the NA-sensitive neurons (n = 123) were NA-inhibited neurons (n = 100), and were found most often in layers III and IV. The ratio of DA-sensitive neurons (excited, n = 74; inhibited, n = 63) to tested neurons was higher in the deep layers than in the superficial ones. These results indicate that sensitivities of the PFC neurons to ACh, NA and DA are not uniform between cortical layers, suggesting that each of these substances may predominantly influence the neuronal activity of particular layers of the monkey PFC.
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D004298:Dopamine / Q000494:pharmacology*; D005625:Frontal Lobe / Q000187:drug effects*; D008251:Macaca; D008253:Macaca mulatta; D009638:Norepinephrine / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects
D000109:Acetylcholine; D004298:Dopamine; D009638:Norepinephrine