500 Hz) thus appears to be lower than it really is, whereas a vibration whose frequency is lower to the preferred one (e.g. In this condition, a high frequency vibration (e.g. It is quite remarkable!' This illusion follows a simple principle: frequencies that are higher or lower than the most sensitive frequency - 250 Hz for humans and 1000 Hz for mice - are felt as more similar to this preferred frequency when their amplitude is increased. A specific choice of their respective amplitudes can actually create perceptual metamers: physically different frequencies that are perceptually indistinguishable. 'However, both mice and humans have a harder time differentiating a lower from a higher frequency when their amplitudes are not matched. 'It turns out that mice are more sensitive to higher frequencies (about 1000 Hz), whereas the human sensitivity is optimal in the much lower frequency range, around 250 Hz,' explains Mario Prsa, professor in the Department of Neuroscience in the Faculty of Science and Medicine at UNIFR and the first author of the study. To this end, the scientists performed the same experiment in a group of mice and a group of human participants, in which they had to differentiate multiple vibration frequencies felt on the hand or the paw. 'How does our brain interpret these physical characteristics? This is the question we aimed to answer in our study.' 'When for instance our phone vibrates, the vibration can vary more or less rapidly - its frequency - and more or less strongly - its amplitude,' explains Daniel Huber, professor in the Department of Basic Neuroscience at UNIGE Faculty of Medicine, who directed the study. the number of repetitions per second) and amplitude, which corresponds to the maximal size the wave can reach, in other words its intensity.

Vibrations are defined by two principle features: frequency, which signals the rate of change in Hz (i.e.

By propagating as waves through solid materials, they can be perceived by most living organisms. Vibrations are small oscillatory movements emitted from a point of equilibrium.

Telescopes auditory illusions