Dissociation of nicotinic α7 and α4/β2 sub-receptor agonists for enhancing learning and attentional filtering in nonhuman primates

• Published in: Psychopharmacology Vol. 237; no. 4; pp. 997 - 1010
• Main Authors: Azimi, Marzyeh, Oemisch, Mariann, Womelsdorf, Thilo
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2020; Springer Nature B.V
• Subjects: Acetylcholine receptors (nicotinic); Agonists; alpha7 Nicotinic Acetylcholine Receptor - agonists; alpha7 Nicotinic Acetylcholine Receptor - physiology; Alzheimer's disease; Animals; Attention; Attention - drug effects; Attention - physiology; Biomedical and Life Sciences; Biomedicine; Executive function; Flexibility; Macaca mulatta; Male; Mental disorders; Monkeys & apes; Motivation; Neurosciences; Nicotine - pharmacology; Nicotinic Agonists - pharmacology; Original Investigation; Pharmacology/Toxicology; Prefrontal cortex; Prefrontal Cortex - drug effects; Prefrontal Cortex - physiology; Primates; Psychiatry; Psychopharmacology; Receptors, Nicotinic - physiology; Reinforcement; Reversal learning; Reversal Learning - drug effects; Reversal Learning - physiology; Acetylcholine; Reversal learning; Nonhuman primate; Attention; Nicotine
• ISSN: 0033-3158; 1432-2072; 1432-2072
• DOI: 10.1007/s00213-019-05430-w

Rationale Nicotinic acetylcholine receptors (nAChRs) modulate attention, memory, and higher executive functioning, but it is unclear how nACh sub-receptors mediate different mechanisms supporting these functions. Objectives We investigated whether selective agonists for the alpha-7 nAChR versus the alpha-4/beta-2 nAChR have unique functional contributions for value learning and attentional filtering of distractors in the nonhuman primate. Methods Two adult rhesus macaque monkeys performed reversal learning following systemic administration of either the alpha-7 nAChR agonist PHA-543613 or the alpha-4/beta-2 nAChR agonist ABT-089 or a vehicle control. Behavioral analysis quantified performance accuracy, speed of processing, reversal learning speed, the control of distractor interference, perseveration tendencies, and motivation. Results We found that the alpha-7 nAChR agonist PHA-543613 enhanced the learning speed of feature values but did not modulate how salient distracting information was filtered from ongoing choice processes. In contrast, the selective alpha-4/beta-2 nAChR agonist ABT-089 did not affect learning speed but reduced distractibility. This dissociation was dose-dependent and evident in the absence of systematic changes in overall performance, reward intake, motivation to perform the task, perseveration tendencies, or reaction times. Conclusions These results suggest nicotinic sub-receptor specific mechanisms consistent with (1) alpha-4/beta-2 nAChR specific amplification of cholinergic transients in prefrontal cortex linked to enhanced cue detection in light of interferences, and (2) alpha-7 nAChR specific activation prolonging cholinergic transients, which could facilitate subjects to follow-through with newly established attentional strategies when outcome contingencies change. These insights will be critical for developing function-specific drugs alleviating attention and learning deficits in neuro-psychiatric diseases.