The Effects of Human Visual Sensory Stimuli on N1b Amplitude: An EEG Study

Abstract

Sensory systems are widely known to exhibit adaptive mechanisms. Vision is no exception to input dependent changes in its sensitivity. Recent animal work demonstrates enhanced connectivity between neurons in the visual cortex. The purpose of the present experiment was to evaluate a human model that noninvasively alters the amplitude of the N1b component in the visual cortex of humans by means of rapid visual stimulation. Nineteen participants (Mage = 24 years; 52.6% male) completed a rapid visual stimulation paradigm involving black and white reversal checkerboards presented bilaterally in the visual field. EEG data was collected during the visual stimulation paradigm, which consisted of four main phases, a pre-tetanus block, photic stimulus, early post-tetanus, and late post-tetanus. The amplitude of the N1b component of the pre-tetanus, early post-tetanus and late post-tetanus visual evoked potentials were calculated. Change in N1b amplitude was calculated by subtracting pre-tetanus N1b amplitude from early and late post-tetanus. Results demonstrated a significant difference between pre-tetanus N1b (M = −0.498 µV, SD = 0.858) and early N1b (M = −1.011 µV, SD = 1.088), t (18) = 2.761, p = 0.039, d = 0.633. No difference was observed between pre-tetanus N1b and late N1b (p = 0.36). In conclusion, our findings suggest that it is possible to induce changes in the amplitude of the visually evoked potential N1b waveform in the visual cortex of humans non-invasively. Additional work is needed to corroborate that the potentiation of the N1b component observed in this study is due to similar mechanisms essential to prolonged strengthened neural connections exhibited in cognitive structures of the brain observed in prior animal research. If so, this will allow for the examination of strengthened neural connectivity and its interaction with multiple human sensory stimuli and behaviors.

The association of self-reported physical activity on human sensory long-term potentiation

“…In summary, and as we demonstrated in our earlier publication [22] , our findings suggest that it is possible to induce an LTP-like response in the visual cortex of humans non-invasively. Subsequently, and as shown herein, meeting exercise guidelines may, potentially, influence N1b amplitude.…”

“…As reported in our previous publication [22] , and in alignment with other studies that have used a visual paradigm [16] , [17] , visual stimuli consisted of black and white reversal checkerboards presented bilaterally in the visual field. The stimuli subtended 4° of visual angle from the vertical and horizontal midline.…”

“…Data within this manuscript originates from a previous publication [22] where we examined the effects of human visual sensory stimuli on N1b amplitude in young adults. Our current paper differs from the previous in that, for this paper, we evaluate the association of self-reported exercise on human sensory LTP-like responses.…”

“…As described in our previous publication [22] , EEG data were collected using a NuAmps 40 channel, 22-bit, digital amplifier (Compumedics Neuroscan) with a fitted 32-channel Quik-Cap with integrated bipolar leads for vertical and horizontal eye movement. Quik-Caps were manufactured of highly elastic breathable Lycra material with soft neoprene electrode gel reservoirs for enhanced patient comfort.…”

Sensory Tetanization to Induce LTP-Like Plasticity: A Review and Reassessment of the Approach

“…While sensory SENSORY TETANIZATION TO INDUCE LTP-LIKE PLASTICITY 24 tetanization may be a valuable non-invasive approach to induce LTP-like plasticity in humans (Kirk et al, 2021;Sumner et al, 2020b), contrasting effects across studies must be considered. As previously discussed, some studies find that tetanization can increase the amplitude of event related potentials (Kleeva et al, 2022;Lei et al, 2017;Lengali et al, 2021;McNair et al, 2006;Moore et al, 2020;Moore & Loprinzi, 2021;Normann et al, 2007;Ross et al, 2008;Rygvold et al, 2020;Smallwood et al, 2015;Spriggs et al, 2017;Spriggs et al, 2018;Spriggs et al, 2019;Sumner et al, 2018;Wilson et al, 2017;Zak et al, 2018), others find no change in response amplitude following tetanization (D'Souza et al, 2018;Rygvold et al, 2020;Sumner et al, 2018), and still others, including ourselves, find that response amplitudes decrease after tetanization (Kleeva et al, 2022;Klöppel et al, 2015;Rebreikina et al, 2021;Wynn et al, 2019). These conflicting results are troubling, especially when considering that most studies use methods very similar to those initially reported by Clapp et al (2005a) and Teyler et al (2005).…”