Improving Visual Sensitivity with Subthreshold Transcranial Magnetic Stimulation

Abrahamyan, Arman; Clifford, Colin W. G.; Arabzadeh, Ehsan; Harris, Justin A.

doi:10.1523/jneurosci.6256-10.2011

Cited by 63 publications

(73 citation statements)

References 23 publications

(33 reference statements)

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“…Indeed, subthreshold TMS enhances visual perceptual performance to boost the detection of visual stimuli (Abrahamyan et al, 2011). However, we found no difference in baseline TMS intensities between drug conditions determined during the calibration phase, potentially excluding changes in responsiveness to TMS as an explanation for our results.…”

Section: Discussioncontrasting

confidence: 60%

Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

Yousif¹,

Bourquin

et al. 2016

J. Neurosci.

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When processing sensory signals, the brain must account for noise, both noise in the stimulus and that arising from within its own neuronal circuitry. Dopamine receptor activation is known to enhance both visual cortical signal-to-noise-ratio (SNR) and visual perceptual performance; however, it is unknown whether these two dopamine-mediated phenomena are linked. To assess this, we used single-pulse transcranial magnetic stimulation (TMS) applied to visual cortical area V5/MT to reduce the SNR focally and thus disrupt visual motion discrimination performance to visual targets located in the same retinotopic space. The hypothesis that dopamine receptor activation enhances perceptual performance by improving cortical SNR predicts that dopamine activation should antagonize TMS disruption of visual perception. We assessed this hypothesis via a double-blinded, placebo-controlled study with the dopamine receptor agonists cabergoline (a D2 agonist) and pergolide (a D1/D2 agonist) administered in separate sessions (separated by 2 weeks) in 12 healthy volunteers in a William's balance-order design. TMS degraded visual motion perception when the evoked phosphene and the visual stimulus overlapped in time and space in the placebo and cabergoline conditions, but not in the pergolide condition. This suggests that dopamine D1 or combined D1 and D2 receptor activation enhances cortical SNR to boost perceptual performance. That local visual cortical excitability was unchanged across drug conditions suggests the involvement of long-range intracortical interactions in this D1 effect. Because increased internal noise (and thus lower SNR) can impair visual perceptual learning, improving visual cortical SNR via D1/D2 agonist therapy may be useful in boosting rehabilitation programs involving visual perceptual training.

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Section: Discussioncontrasting

confidence: 60%

Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

Yousif¹,

Bourquin

et al. 2016

J. Neurosci.

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“…They reported that the photon emissions were strongly correlated with EEG activity and the emergence of action potentials in axons. Phosphenes can also interfere and impair the detection of visual stimuli and imagery (Abrahamya et al, 2011;van de Ven and Sack, 2013).…”

Section: Summary Discussion Implications and Outlookmentioning

confidence: 99%

Phosphene perception is due to the ultra-weak photon emission produced in various parts of the visual system: glutamate in the focus

Császár¹,

Scholkmann²,

Salari³

et al. 2016

Reviews in the Neurosciences

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AbstractPhosphenes are experienced sensations of light, when there is no light causing them. The physiological processes underlying this phenomenon are still not well understood. Previously, we proposed a novel biopsychophysical approach concerning the cause of phosphenes based on the assumption that cellular endogenous ultra-weak photon emission (UPE) is the biophysical cause leading to the sensation of phosphenes. Briefly summarized, the visual sensation of light (phosphenes) is likely to be due to the inherent perception of UPE of cells in the visual system. If the intensity of spontaneous or induced photon emission of cells in the visual system exceeds a distinct threshold, it is hypothesized that it can become a conscious light sensation. Discussing several new and previous experiments, we point out that the UPE theory of phosphenes should be really considered as a scientifically appropriate and provable mechanism to explain the physiological basis of phosphenes. In the present paper, we also present our idea that some experiments may support that the cortical phosphene lights are due to the glutamate-related excess UPE in the occipital cortex.

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“…Unlike the present study, Schwarzkopf et al (2011) used motion stimuli and targeted MT rather than the primary visual cortex and delivered a triple-pulse TMS (pulse gap of 50 ms). Abrahamyan et al (2011) used much larger stimuli than in the current study (6.5°compared with 0.2°visual angle in our study; a difference of over 30 times) and used a two-interval, forced-choice detection task, which requires very different neural computation compared with our single-stimulus discrimination task (Macmillan and Creelman 2005). Overall, the differences among the current study and the previous studies Koivisto et al 2010;Schwarzkopf et al 2011) prevent any conclusions about the general effects of subthreshold TMS on accuracy, as these effects likely depend on factors such as size and type of stimulus used, stimulation site, stimulation procedure, and precise stimulation intensity.…”

Section: Does Tms Affect Noise or Mean Signal Intensity For Visual Pementioning

confidence: 94%

Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence

Rahnev

Maniscalco

Luber

et al. 2012

Journal of Neurophysiology

117

131

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Rahnev DA, Maniscalco B, Luber B, Lau H, Lisanby SH. Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence. J Neurophysiol 107: 1556 -1563, 2012. First published December 14, 2011 doi:10.1152/jn.00985.2011The relationship between accuracy and confidence in psychophysical tasks traditionally has been assumed to be mainly positive, i.e., the two typically increase or decrease together. However, recent studies have reported examples of exceptions, where confidence and accuracy dissociate from each other. Explanations for such dissociations often involve dual-channel models, in which a cortical channel contributes to both accuracy and confidence, whereas a subcortical channel only contributes to accuracy. Here, we show that a single-channel model derived from signal detection theory (SDT) can also account for such dissociations. We applied transcranial magnetic stimulation (TMS) to the occipital cortex to disrupt the internal representation of a visual stimulus. The results showed that consistent with previous research, occipital TMS decreased accuracy. However, counterintuitively, it also led to an increase in confidence ratings. The data were predicted well by a single-channel SDT model, which posits that occipital TMS increased the variance of the internal stimulus distributions. A formal model comparison analysis that used information theoretic methods confirmed that this model was preferred over single-channel models, in which occipital TMS changed the signal strength or dual-channel models, which assume two different processing routes. Thus our results show that dissociations between accuracy and confidence can, at least in some cases, be accounted for by a single-channel model.

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Improving Visual Sensitivity with Subthreshold Transcranial Magnetic Stimulation

Cited by 63 publications

References 23 publications

Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

Phosphene perception is due to the ultra-weak photon emission produced in various parts of the visual system: glutamate in the focus

Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence

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