Serotonin transporter knockout in rats reduces beta- and gamma-band functional connectivity between the orbitofrontal cortex and amygdala during auditory discrimination

• Published in: Cerebral cortex (New York, N.Y. 1991) N.Y. 1991), 2024-08, Vol.34 (8)
• Main Authors: Boillot, Morgane, ter Horst, Jordi, López, José Rey, Di Fazio, Ilaria, Steens, Indra L M, Cohen, Michael X, Homberg, Judith R
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Amygdala - physiology; Animals; Auditory Perception - physiology; Beta Rhythm - physiology; Discrimination, Psychological - physiology; Gamma Rhythm - physiology; Male; Neural Pathways - physiology; Original; Prefrontal Cortex - physiology; Rats; Rats, Transgenic; Reward; Serotonin Plasma Membrane Transport Proteins - deficiency; Serotonin Plasma Membrane Transport Proteins - genetics
• ISSN: 1047-3211; 1460-2199; 1460-2199
• DOI: 10.1093/cercor/bhae334

Abstract The orbitofrontal cortex and amygdala collaborate in outcome-guided decision-making through reciprocal projections. While serotonin transporter knockout (SERT−/−) rodents show changes in outcome-guided decision-making, and in orbitofrontal cortex and amygdala neuronal activity, it remains unclear whether SERT genotype modulates orbitofrontal cortex–amygdala synchronization. We trained SERT−/− and SERT+/+ male rats to execute a task requiring to discriminate between two auditory stimuli, one predictive of a reward (CS+) and the other not (CS−), by responding through nose pokes in opposite-side ports. Overall, task acquisition was not influenced by genotype. Next, we simultaneously recorded local field potentials in the orbitofrontal cortex and amygdala of both hemispheres while the rats performed the task. Behaviorally, SERT−/− rats showed a nonsignificant trend for more accurate responses to the CS−. Electrophysiologically, orbitofrontal cortex—amygdala synchronization in the beta and gamma frequency bands during response selection was significantly reduced and associated with decreased hubness and clustering coefficient in both regions in SERT−/− rats compared to SERT+/+ rats. Conversely, theta synchronization at the time of behavioral response in the port associated with reward was similar in both genotypes. Together, our findings reveal the modulation by SERT genotype of the orbitofrontal cortex—amygdala functional connectivity during an auditory discrimination task.