Feedback was presented on the screen after each choice as ‘CORRECT’ and ‘INCORRECT”.
LUCA VISUAL FX SERIAL MAC SERIES
Probabilistic reversal learning task : Participants made a two-alternative forced choice between two patterns (green and red) over a series of trials by touching the screen. An additional important feature of this study was its relatively novel examination of possible influences of gender, depressive symptoms and trait anxiety on the effects of escitalopram.ġ.
Detailed hypotheses are described in the Methods section. We included (i) a probabilistic and reversal learning task (ii) the CANTAB Intra-dimensional/Extra-dimensional set shift test, which includes reversal learning components (iii) a combined Stop-signal/Go/No-Go response inhibition task that measures both restraint and cancellation types of response inhibition in the same subjects and (iv) emotional processing and social cognition tasks including the CANTAB affective Go/No-Go task, and the face affective Go/No-Go task and social information preference task, both from the newly developed EMOTICOM test battery.
This study examined the effects of acute escitalopram in healthy human volunteers on a test battery used extensively in both human and animal studies, assessing fronto-executive functions and previously shown to be sensitive to serotonergic manipulations. Moreover, selective serotonin reuptake inhibitors (SSRIs) constitute the first-line treatment for mood disorders. These findings have clinical implications, as depressed humans show deficits in cognitive flexibility and exaggerated reactions to negative feedback mediated by the prefrontal cortex (PFC) and the amygdala. However, higher doses or sub-chronic treatment with citalopram improve performance in probabilistic reversal learning tasks in rats. This is analogous to the effects of an acute low dose of citalopram in healthy volunteers and rats hypothesised to arise from inhibitory effects on 5-HT transmission. ATD impairs visual discrimination learning and reversal, while selective 5-HT depletion in the amygdala has been shown to increase sensitivity to aversive feedback in probabilistic learning and reversal tasks. Much of the relevant evidence has depended on examining the effects of 5-HT loss in humans using acute dietary tryptophan depletion (ATD), or in experimental animals, using 5-HT neurotoxins such as 5,7-dihydroxytryptamine (5,7-DHT) (e.g. Serotonin (5-HT) is implicated in learning, executive and affective functions. Our findings suggest a dissociation of effects of acute escitalopram on cognitive functions, possibly mediated by differential modulation of brain serotonin levels in distinct functional neural circuits. We showed that acute escitalopram administration impaired learning and cognitive flexibility, but improved the ability to inhibit responses in stop-signal trials while leaving unaffected acute emotional processing. Participants performed a cognitive test battery including a probabilistic and reversal learning task, the CANTAB intra-dimensional/extra-dimensional shift test of cognitive flexibility, a response inhibition task with interleaved stop-signal and No-Go trials and tasks measuring emotional processing. We tested the cognitive effects of the selective serotonin reuptake inhibitor escitalopram, using an acute and clinically relevant dose (20 mg), in 66 healthy male and female volunteers in a double-blind, placebo-controlled study. These functions are impaired in several psychiatric disorders, such as depression and obsessive–compulsive disorder. Serotonin is implicated in multiple executive functions including goal-directed learning, cognitive flexibility, response inhibition and emotional regulation.
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