Modulation of Synaptic Plasticity by Vibratory Training in Young and Old Mice

Abstract

In the past 40 years, scientific research has shown how Whole Body Vibration concept represents a strong stimulus for the whole organism. Low (<30 Hz), medium (30–80 Hz), and high (>80 Hz) frequency vibrations can have both positive and negative effects, depending on the oscillation type and duration of exposure to which the body is subjected. However, very little is known about the effects of vibratory training on the brain. In this regard, we verified whether three vibratory training protocols, differing in terms of vibration frequency and exposure time to vibration, could modulate synaptic plasticity in an experimental mouse model, by extracellular recordings in vitro in hippocampal slices of mice of 4 and 24 months old. Our results showed that vibratory training can modulate synaptic plasticity differently, depending on the protocol used, and that the best effects are related to the training protocol characterized by a low vibration frequency and a longer recovery time. Future studies will aim to understand the brain responses to various types of vibratory training and to explore the underlying mechanisms, also evaluating the presence of any structural and functional changes due to vibratory training.

Dose–Response Effect of Vibratory Stimulus on Synaptic and Muscle Plasticity in a Middle-Aged Murine Model

“…In our previous work, we reported that exposure to an appropriate WBV protocol improves learning and memory processes in old mice (Cariati et al, 2021). These brain functions are particularly susceptible to the aging process.…”

“…Vibration training was conducted using three protocols (A, B, and C), which differ in terms of vibration frequency and exposure time to vibration (Cariati et al, 2021). The A and B protocols consisted of five series (consecutive number of repetitions) of 3 min each, interspersed with 1 min of recovery.…”

“…The C protocol consisted of three series of 2 min and 30 s each, with a recovery period of equal duration. The vibration frequency used was 90 Hz for the A protocol and 45 Hz for B and C protocols (Cariati et al, 2021). The animals underwent a total of 36 days of activity; specifically, each group of mice was trained for 12 weeks, on a 3-weekly basis.…”

“…Based on these considerations, in our previous work we evaluated the effects of three WBV training protocols, differing in vibration frequency and vibration exposure time, on synaptic plasticity in an experimental mouse model, by means of in vitro extracellular recordings in hippocampal slices from 4to 24-month-old mice (Cariati et al, 2021). It was previously suggested that synaptic plasticity is positively affected by WBV training, both in rodents (Manthou et al, 2017) and in humans (Fuermaier et al, 2014;Regterschot et al, 2014), probably through the involvement of sensory stimulation leading to cognitive enhancement.…”

“…In agreement with these studies, our results showed that WBV training can modulate synaptic plasticity differently, depending on the protocol used, and that the best effects are related to the training protocol characterized by a low vibration frequency and a longer recovery time. Surprisingly, 24-month-old mice exposed to mechanical vibrations showed full recovery of cognitive capacity (Cariati et al, 2021), suggesting that vibratory training may be considered an important factor in protecting and/or preventing the development of age-related cognitive disorders, which in turn is closely related to synaptic plasticity (Weber et al, 2015;De Domenico et al, 2017). It is well known that aging is a biological process associated with physiological cognitive decline, as it can impair quality of life and cause deficits in memory and learning processes (Bettio et al, 2017).…”