Limits...
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 4 (bars instead of faces; one hour delay).Error Rates on ‘competitive trials’ for each stimulation condition: LTP 10 Hz = task-relevant stimulation (luminance change) at 10Hz; LTP 20 Hz = task-relevant stimulation (luminance change) at 20Hz; NoStim = no stimulation. Arrow indicates when the stimulation was applied and followed by 1 hour delay. Error bars = +/- 1 SEM across subjects.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4920386&req=5

pone.0158312.g005: Experiment 4 (bars instead of faces; one hour delay).Error Rates on ‘competitive trials’ for each stimulation condition: LTP 10 Hz = task-relevant stimulation (luminance change) at 10Hz; LTP 20 Hz = task-relevant stimulation (luminance change) at 20Hz; NoStim = no stimulation. Arrow indicates when the stimulation was applied and followed by 1 hour delay. Error bars = +/- 1 SEM across subjects.

Mentions: As illustrated in Fig 5, we could not replicate any long-term (1 hour delay) frequency-dependent stimulation effects on low-level visual processing (Group x Time: F(2,59) = 1.82, p = 0.17). It should be noted that the protocol of exp.4 still slightly differed from the one used by Beste and colleagues in the following aspects: 1) saliency level of the distractor: only one level here, while they used two levels (they found differential strength and duration of stimulation effects depending on the saliency level, and it is difficult to exactly say where saliency in our experiment falls within their tested range); 2) number of trials before and after stimulation (432 here vs 512 in Beste et al.); 3) context of conditions: we included an additional “no-change” condition in 1/9th of the trials); 4) distance of stimuli to fixation cross: 2.1 degrees here vs 1.1 degree there). However, we tested 10 additional subjects with a 1.1 degree distance between stimuli and fixation cross and the performance did not change at baseline nor at post-stimulation blocks.


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 4 (bars instead of faces; one hour delay).Error Rates on ‘competitive trials’ for each stimulation condition: LTP 10 Hz = task-relevant stimulation (luminance change) at 10Hz; LTP 20 Hz = task-relevant stimulation (luminance change) at 20Hz; NoStim = no stimulation. Arrow indicates when the stimulation was applied and followed by 1 hour delay. Error bars = +/- 1 SEM across subjects.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920386&req=5

pone.0158312.g005: Experiment 4 (bars instead of faces; one hour delay).Error Rates on ‘competitive trials’ for each stimulation condition: LTP 10 Hz = task-relevant stimulation (luminance change) at 10Hz; LTP 20 Hz = task-relevant stimulation (luminance change) at 20Hz; NoStim = no stimulation. Arrow indicates when the stimulation was applied and followed by 1 hour delay. Error bars = +/- 1 SEM across subjects.
Mentions: As illustrated in Fig 5, we could not replicate any long-term (1 hour delay) frequency-dependent stimulation effects on low-level visual processing (Group x Time: F(2,59) = 1.82, p = 0.17). It should be noted that the protocol of exp.4 still slightly differed from the one used by Beste and colleagues in the following aspects: 1) saliency level of the distractor: only one level here, while they used two levels (they found differential strength and duration of stimulation effects depending on the saliency level, and it is difficult to exactly say where saliency in our experiment falls within their tested range); 2) number of trials before and after stimulation (432 here vs 512 in Beste et al.); 3) context of conditions: we included an additional “no-change” condition in 1/9th of the trials); 4) distance of stimuli to fixation cross: 2.1 degrees here vs 1.1 degree there). However, we tested 10 additional subjects with a 1.1 degree distance between stimuli and fixation cross and the performance did not change at baseline nor at post-stimulation blocks.

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