Serotonergic modulation of response inhibition and re-engagement? Results of a study in healthy human volunteers.
OBJECTIVE
Cognitive functions dependent on the prefrontal cortex, such as the ability to suppress behavior (response inhibition) and initiate a new one (response re-engagement) is important in the activities of daily life. Central serotonin (5-HT) function is thought to be a critical component of these cognitive functions. In recent studies, 5-HT failed to affect stop-signal reaction time (SSRT), a fundamental process in behavioral inhibition. We were interested if response inhibition and re-engagement are influenced through central 5-HT activity as mediated via the 5-HT transporter.


METHODS
Here, using a stop-change task, we investigated the effects of acute and repeated treatment with 10 mg escitalopram, a selective 5-HT reuptake inhibitor, in 36 healthy human volunteers on response inhibition and re-engagement in a randomized, double-blind, placebo-controlled study with cross-over design.


RESULTS
Results do not show an influence of escitalopram on response inhibition or response re-engagement as we did not find differences in SSRT or change reaction time (CRT).


CONCLUSIONS
These findings support the results of previous studies suggesting that 5-HT is not critical in inhibition of already initiated responses and response re-engagement. We hypothesize that results are due to different forms of behavioral inhibition and 5-HT may critical to other forms.
Drueke
Barbara
B
Department of Medical Psychology and Medical Sociology, RWTH Aachen University, Pauwelsstrasse, Germany. bdrueke@ukaachen.de
Boecker
Maren
M
Schlaegel
Sonja
S
Moeller
Olaf
O
Hiemke
Christoph
C
Gründer
Gerhard
G
Gauggel
Siegfried
S
D000328:Adult; D015283:Citalopram / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D011930:Reaction Time / Q000187:drug effects*; D012701:Serotonin / Q000378:metabolism; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*
D015283:Citalopram; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors