Caffeine-induced arousal modulates somatomotor and autonomic differential classical conditioning in humans

Abstract

Two experiments (n = 48 and n = 45) investigated the effects of caffeine-induced arousal on differential classical conditioning of eyeblink (experiment 1) and autonomic (experiment 2) responses. Three groups of human subjects received double-blind administration of 0, 2, and 4 mg/kg oral caffeine (groups 0, 2, and 4, respectively). Twenty minutes after caffeine administration, a differential classical conditioning procedure was in effect. Physiological and subjective arousal was assessed by readings of blood pressure, skin conductance level, and a questionnaire, administered before caffeine administration, and after the conditioning procedure. The results showed increased indexes of physiological arousal in groups 2 and 4. In experiment 1, differential classical eyeblink conditioning was observed in groups 0 and 4, whereas no differential conditioning was seen in group 2. In experiment 2, differential classical conditioning was seen in group 0, whereas caffeine-induced arousal masked acquisition of conditioned skin conductance responses in group 4. This group displayed increased resistance to extinction compared to the other groups. Group 2, which had an intermediate level of arousal, did not display differential conditioning in either experiment. Taken together, the results indicate that small increases in arousal may be detrimental to learning, and larger increases in arousal may reverse this effect.

Disruption of bradycardia associated with discriminative conditioning in combat veterans with PTSD

“…In contrast, and of special interest, is the finding of a study of human subjects by Flaten (1998), which used apparatus and stimulus parameters very similar to those of the present study. Experimentally induced high arousal (4 mg/kg oral caffeine) produced differential CS+/CS− EB conditioning but CS+/CS− differentiation by HR did not occur, even though the first and second HR decelerative components (D1 and D2 respectively) both increased—indicating orienting (the D1 component) and contingent (D2) HR decelerative responding to CS+/US pairings (Flaten 1998). These results seem to be compatible with those of the present study.…”

Highly reproducible eyeblink timing during formula car driving

“…According to previous research, caffeine intake significantly impacts the eyeblink conditioning process depending on the dosage volume. 48 However, to the best of our exploration, there is no impact on eyeblink rate, 49 and no study has been found on the relationship between caffeine and eyeblink timing. It cannot be denied that caffeine impacted our results through the unreported association, so future studies should consider monitoring caffeine intake.…”