Visuo-Acoustic Stimulation’s Role in Synaptic Plasticity: A Review of the Literature

Abstract

Brain plasticity is the capacity of cerebral neurons to change, structurally and functionally, in response to experiences. This is an essential property underlying the maturation of sensory functions, learning and memory processes, and brain repair in response to the occurrence of diseases and trauma. In this field, the visual system emerges as a paradigmatic research model, both for basic research studies and for translational investigations. The auditory system remains capable of reorganizing itself in response to different auditory stimulations or sensory organ modification. Acoustic biofeedback training can be an effective way to train patients with the central scotoma, who have poor fixation stability and poor visual acuity, in order to bring fixation on an eccentrical and healthy area of the retina: a pseudofovea. This review article is focused on the cellular and molecular mechanisms underlying retinal sensitivity changes and visual and auditory system plasticity.

Noradrenergic substrates sensing light within brainstem reticular formation as targets for light-induced behavioral and cardiovascular plasticity

“…This brings intriguing questions on the potential synergy in the form of synesthesia, which may act on retinal stem cells, when pulses of electromagnetic fields are coupled with pulses of acoustic energy. In fact, as recently reported, the training of patients suffering from central scotoma with acoustic biofeedback can progressively improve visual acuity, by moving fixation to eccentrically placed healthy area of the retina, which is primed to act as a "pseudo-fovea" (Tonti et al, 2021). In keeping with plasticity induced by pure light, which occurs depending on pulses of electromagnetic wavelengths, it is remarkable that both blue light, which stimulates stem cells to form glia, and red light, which stimulates the stem cells to form neurons need to be applied according to intermittent patterns.…”

Resonance Scanning as an Efficiency Enhancer for EEG-Guided Adaptive Neurostimulation

“…Resonance scanning makes it possible to observe the dynamics of resonant EEG responses at the stimulation frequency (rhythm entrainment) and at the frequency of harmonics (rhythm multiplication). From the literature, it is known that these EEG responses reflect the degree of functional lability, adaptive potential, and non-linearity of brain reactions due to the mechanisms of interaction between endogenous and exogenous oscillations [ 13 ], neural entrainment [ 14 , 15 ], and controlled neuroplasticity [ 16 , 17 ]. Based on these mechanisms, resonance scanning increases the brain’s responsiveness to subsequent adaptive neurostimulation, acting as a kind of pre-tuning of the brain, which cause the activation of potential resonators in the EEG spectrum.…”

Effectiveness of Mp-3 Microperimetric Biofeedback Fixation Training For Low Vision Rehabilitation in Patients Treated With Corticosteroid Ivt in Retinal Vein Occlusions

“…MBFT establishes a new preferred fixation point, and through its use, it is possible to assess retinal sensitivity and fixation stability in a combined manner, allowing for diagnosis and visual rehabilitation even in patients with fixation problems. 17 …”

“…MBFT establishes a new preferred fixation point, and through its use, it is possible to assess retinal sensitivity and fixation stability in a combined manner, allowing for diagnosis and visual rehabilitation even in patients with fixation problems. 17 The biofeedback method involves instructing patients to choose a final fixation position, thereby improving visual reading speed and using a new peripheral retinal area to perform visual tasks. This area, called the Preferred Retinal Locus (PRL), acts as a new oculomotor reference point.…”

“…This area, called the Preferred Retinal Locus (PRL), acts as a new oculomotor reference point. 17 Oculomotor training would result in an increase in gray and white matter density in the cerebellum, indicating learning in performing visual tasks with eccentric vision. 18 Microperimetric biofeedback contributes to strengthening the PRL and enhances activation of the visual cortex.…”