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

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).

Differential effects of the temporal and spatial distribution of audiovisual stimuli on cross‐modal spatial recalibration

“…Exposure‐based learning has most often been investigated in the context of unisensory perceptual learning studies (Beste & Dinse, 2013). For instance, prolonged passive sensory stimulation has been shown to enhance tactile acuity (Dinse, Ragert, Pleger, Schwenkreis, & Tegenthoff, 2003; Godde, Stauffenberg, Spengler, & Dinse, 2000), visual luminance change detection (Beste, Wascher, Güntürkün, & Dinse, 2011; Marzoll, Saygi, & Dinse, 2018), and face identity detection (Pegado, Vankrunkelsven, Steyaert, Boets, & Op de Beeck, 2016). Importantly, these unisensory learning effects depended on the temporal pattern of stimulation.…”

“…Improvements were observed only when stimuli were presented intermittently at a high frequency of 10–20 Hz. By contrast, continuous stimulation at a low frequency of 1 Hz, which is similar to stimulation protocols commonly used to induce cross‐modal recalibration, resulted in an impairment of visual and tactile discrimination performance (Beste et al., 2011; Pegado et al., 2016; Ragert, Kalisch, Bliem, Franzkowiak, & Dinse, 2008). In these studies, high‐ and low‐frequency stimulation protocols were specifically designed to mimic protocols that are known to induce long‐term potentiation (LTP) and long‐term depression (LTD) of synaptic transmission at a cellular level (Bear & Malenka, 1994).…”

The effect of LTP- and LTD-like visual stimulation on modulation of human orientation discrimination

“…LTP-/LTD-like visual stimulation approaches have been used to modulate the detection of relevant and irrelevant stimuli in a change detection task 35 , and in a face recognition task 36 . While these studies addressed the question of whether this approach is suitable for the investigation of higher order cognitive functions, little is known about the effectiveness of LTP-/LTD-like visual stimulation in altering low-level perceptual abilities as was the case in the tactile domain, where most studies assessed changes of tactile spatial discrimination as a marker of plastic changes 20 – 22 .…”

High frequency visual stimulation primes gamma oscillations for visually-evoked phase reset and enhances spatial acuity

“…Experiments designed to explore sensory stimulation with temporal frequencies associated with LTP induction, demonstrate that tetanic stimulation induces enhances response amplitude, discrimination and perception in visual, auditory and somatosensory systems (Beste et al, 2011;Brickwedde et al, 2020;Pegado et al, 2016;Sanders et al, 2018). Potentiation induced by non-invasive sensory stimulation requires NMDA receptors for the expression of sensory changes indicating an LTP like mechanism (Clapp et al, 2006;Dinse et al, 2003).…”