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Exploring the Use of Sensorial LTP/LTD-Like Stimulation to Modulate Human Performance for Complex Visual Stimuli.

Pegado F, Vankrunkelsven H, Steyaert J, Boets B, Op de Beeck H - PLoS ONE (2016)

Bottom Line: Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3).Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature.Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain and Cognition, KU Leuven, 3000 Leuven, Belgium.

ABSTRACT
Is it possible to passively induce visual learning/unlearning in humans for complex stimuli such as faces? We addressed this question in a series of behavioral studies using passive visual stimulation (flickering of faces at specific temporal frequencies) inspired by well-known synaptic mechanisms of learning: long-term potentiation (LTP) vs long-term depression (LTD). We administered a face identity change detection task before and after a passive stimulation protocol to test for potential changes in visual performance. First, with bilateral stimulation, subjects undergoing high-frequency LTP-like stimulation outperformed those submitted to low-frequency LTD-like stimulation despite equivalent baseline performance (exp. 1). Second, unilateral stimulation replicated the differential modulation of performance, but in a hemifield-specific way (exp. 2). Third, for both stimulation groups, a sudden temporary drop in performance on the stimulated side immediately after the stimulation, followed by progressive recovering, can suggest either 'visual fatigue' or 'face adaptation' effects due to the stimulation. Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3). Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature. Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique. This step is required to consider further use in fundamental research (e.g., to study neural circuits involved in selective visual processing) and potential educational or clinical applications (e.g., inhibiting socially-irrelevant aspects of face processing in autism).

No MeSH data available.


Related in: MedlinePlus

Experiment 3 (one hour delay post-stimulation).Error rates on ‘competitive trials’ for each stimulation condition: LTP relev = high-frequency relevant stimulation (face identity changes); LTP irrelev = high-frequency irrelevant stimulation (head orientation changes); No Stim = control group (without stimulation); LTD = low-frequency relevant stimulation (face identity change). See Results. Error bars = +/- 1 SEM across subjects.
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pone.0158312.g004: Experiment 3 (one hour delay post-stimulation).Error rates on ‘competitive trials’ for each stimulation condition: LTP relev = high-frequency relevant stimulation (face identity changes); LTP irrelev = high-frequency irrelevant stimulation (head orientation changes); No Stim = control group (without stimulation); LTD = low-frequency relevant stimulation (face identity change). See Results. Error bars = +/- 1 SEM across subjects.

Mentions: Overall, we did not find a significant differential modulation of face processing performance by LTP vs LTD like stimulation. In particular there was no significant Group x Time interaction (F(3,92) = 1.85, p = 0.14), suggesting that frequency-dependent stimulation effects have vanished completely after the one hour delay period (see Fig 4). The results for the LTP-like relevant-change stimulation were strikingly similar to the no-stimulation condition, suggesting either no LTP-like effect at all or a short lasting LTP-like effect (between ~15 minutes and one hour). For the LTD-like group the pattern of results was less decisive. Despite the absence of any overall statistical effect when taking all time points into consideration, there was a suggestive drop in performance in the first testing block after LTD-like stimulation (see Fig 4). When restricting the analysis to this time point (i.e. block 4), there was a trend (F(1,93) = 2.99, p = 0.087) towards degraded performance of the LTD-like stimulation group as compared to the three other groups. This trend already disappeared from testing block 5 onwards. Thus even if the increased error rates reflected a long-lasting effect of LTD-like stimulation (present one hour later), it was transient and quickly undone after one block of performing the face processing task (see results for blocks 5 and 6). Overall, Experiment 3 does not provide convincing evidence that the LTP/LTD-like stimulation resulted in long-lasting frequency-dependent changes in behavioral performance.


Exploring the Use of Sensorial LTP/LTD-Like Stimulation to Modulate Human Performance for Complex Visual Stimuli.

Pegado F, Vankrunkelsven H, Steyaert J, Boets B, Op de Beeck H - PLoS ONE (2016)

Experiment 3 (one hour delay post-stimulation).Error rates on ‘competitive trials’ for each stimulation condition: LTP relev = high-frequency relevant stimulation (face identity changes); LTP irrelev = high-frequency irrelevant stimulation (head orientation changes); No Stim = control group (without stimulation); LTD = low-frequency relevant stimulation (face identity change). See Results. Error bars = +/- 1 SEM across subjects.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4920386&req=5

pone.0158312.g004: Experiment 3 (one hour delay post-stimulation).Error rates on ‘competitive trials’ for each stimulation condition: LTP relev = high-frequency relevant stimulation (face identity changes); LTP irrelev = high-frequency irrelevant stimulation (head orientation changes); No Stim = control group (without stimulation); LTD = low-frequency relevant stimulation (face identity change). See Results. Error bars = +/- 1 SEM across subjects.
Mentions: Overall, we did not find a significant differential modulation of face processing performance by LTP vs LTD like stimulation. In particular there was no significant Group x Time interaction (F(3,92) = 1.85, p = 0.14), suggesting that frequency-dependent stimulation effects have vanished completely after the one hour delay period (see Fig 4). The results for the LTP-like relevant-change stimulation were strikingly similar to the no-stimulation condition, suggesting either no LTP-like effect at all or a short lasting LTP-like effect (between ~15 minutes and one hour). For the LTD-like group the pattern of results was less decisive. Despite the absence of any overall statistical effect when taking all time points into consideration, there was a suggestive drop in performance in the first testing block after LTD-like stimulation (see Fig 4). When restricting the analysis to this time point (i.e. block 4), there was a trend (F(1,93) = 2.99, p = 0.087) towards degraded performance of the LTD-like stimulation group as compared to the three other groups. This trend already disappeared from testing block 5 onwards. Thus even if the increased error rates reflected a long-lasting effect of LTD-like stimulation (present one hour later), it was transient and quickly undone after one block of performing the face processing task (see results for blocks 5 and 6). Overall, Experiment 3 does not provide convincing evidence that the LTP/LTD-like stimulation resulted in long-lasting frequency-dependent changes in behavioral performance.

Bottom Line: Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3).Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature.Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain and Cognition, KU Leuven, 3000 Leuven, Belgium.

ABSTRACT
Is it possible to passively induce visual learning/unlearning in humans for complex stimuli such as faces? We addressed this question in a series of behavioral studies using passive visual stimulation (flickering of faces at specific temporal frequencies) inspired by well-known synaptic mechanisms of learning: long-term potentiation (LTP) vs long-term depression (LTD). We administered a face identity change detection task before and after a passive stimulation protocol to test for potential changes in visual performance. First, with bilateral stimulation, subjects undergoing high-frequency LTP-like stimulation outperformed those submitted to low-frequency LTD-like stimulation despite equivalent baseline performance (exp. 1). Second, unilateral stimulation replicated the differential modulation of performance, but in a hemifield-specific way (exp. 2). Third, for both stimulation groups, a sudden temporary drop in performance on the stimulated side immediately after the stimulation, followed by progressive recovering, can suggest either 'visual fatigue' or 'face adaptation' effects due to the stimulation. Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3). Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature. Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique. This step is required to consider further use in fundamental research (e.g., to study neural circuits involved in selective visual processing) and potential educational or clinical applications (e.g., inhibiting socially-irrelevant aspects of face processing in autism).

No MeSH data available.


Related in: MedlinePlus