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Ubiquitous crossmodal Stochastic Resonance in humans: auditory noise facilitates tactile, visual and proprioceptive sensations.

Lugo E, Doti R, Faubert J - PLoS ONE (2008)

Bottom Line: Specifically, we show that the effective auditory noise significantly increased tactile sensations of the finger, decreased luminance and contrast visual thresholds and significantly changed EMG recordings of the leg muscles during posture maintenance.We conclude that crossmodal SR is a ubiquitous phenomenon in humans that can be interpreted within an energy and frequency model of multisensory neurons spontaneous activity.The result is an integrated activation that promotes sensitivity transitions and the signals are then perceived.

View Article: PubMed Central - PubMed

Affiliation: Visual Psychophysics and Perception Laboratory, School of Optometry, University of Montreal, Montreal, Quebec, Canada.

ABSTRACT

Background: Stochastic resonance is a nonlinear phenomenon whereby the addition of noise can improve the detection of weak stimuli. An optimal amount of added noise results in the maximum enhancement, whereas further increases in noise intensity only degrade detection or information content. The phenomenon does not occur in linear systems, where the addition of noise to either the system or the stimulus only degrades the signal quality. Stochastic Resonance (SR) has been extensively studied in different physical systems. It has been extended to human sensory systems where it can be classified as unimodal, central, behavioral and recently crossmodal. However what has not been explored is the extension of this crossmodal SR in humans. For instance, if under the same auditory noise conditions the crossmodal SR persists among different sensory systems.

Methodology/principal findings: Using physiological and psychophysical techniques we demonstrate that the same auditory noise can enhance the sensitivity of tactile, visual and propioceptive system responses to weak signals. Specifically, we show that the effective auditory noise significantly increased tactile sensations of the finger, decreased luminance and contrast visual thresholds and significantly changed EMG recordings of the leg muscles during posture maintenance.

Conclusions/significance: We conclude that crossmodal SR is a ubiquitous phenomenon in humans that can be interpreted within an energy and frequency model of multisensory neurons spontaneous activity. Initially the energy and frequency content of the multisensory neurons' activity (supplied by the weak signals) is not enough to be detected but when the auditory noise enters the brain, it generates a general activation among multisensory neurons of different regions, modifying their original activity. The result is an integrated activation that promotes sensitivity transitions and the signals are then perceived. A physiologically plausible model for crossmodal stochastic resonance is presented.

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Related in: MedlinePlus

Visual stimuli representation.(Top row) Gabor patch signal (left), and carrier consisting of Gaussian noise (right). (Middle row) the spatial representation for luminance modulated (first order) stimuli. (Bottom row) the spatial representation for contrast modulated (second order) stimuli.
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pone-0002860-g011: Visual stimuli representation.(Top row) Gabor patch signal (left), and carrier consisting of Gaussian noise (right). (Middle row) the spatial representation for luminance modulated (first order) stimuli. (Bottom row) the spatial representation for contrast modulated (second order) stimuli.

Mentions: The signal function (S(x, y)) is a Gabor patch displayed in Figure. 11 (top row, left) with a center spatial frequency f of 1 cpd, a standard deviation σ of 1 deg, a phase p randomized at each stimulus presentation and a Michelson contrast C (CLM or CCM depending on the type of modulation) that varied according to the task (see below) S(x, y) is given by:(4)where ri can be the direction x or y. The carrier function N(x, y), shown in Figure 11 (top row, right), generated a matrix of 320 times 320 pixels (5 times 5 deg), each element being randomly selected from a Gaussian distribution centered on 0.


Ubiquitous crossmodal Stochastic Resonance in humans: auditory noise facilitates tactile, visual and proprioceptive sensations.

Lugo E, Doti R, Faubert J - PLoS ONE (2008)

Visual stimuli representation.(Top row) Gabor patch signal (left), and carrier consisting of Gaussian noise (right). (Middle row) the spatial representation for luminance modulated (first order) stimuli. (Bottom row) the spatial representation for contrast modulated (second order) stimuli.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2481403&req=5

pone-0002860-g011: Visual stimuli representation.(Top row) Gabor patch signal (left), and carrier consisting of Gaussian noise (right). (Middle row) the spatial representation for luminance modulated (first order) stimuli. (Bottom row) the spatial representation for contrast modulated (second order) stimuli.
Mentions: The signal function (S(x, y)) is a Gabor patch displayed in Figure. 11 (top row, left) with a center spatial frequency f of 1 cpd, a standard deviation σ of 1 deg, a phase p randomized at each stimulus presentation and a Michelson contrast C (CLM or CCM depending on the type of modulation) that varied according to the task (see below) S(x, y) is given by:(4)where ri can be the direction x or y. The carrier function N(x, y), shown in Figure 11 (top row, right), generated a matrix of 320 times 320 pixels (5 times 5 deg), each element being randomly selected from a Gaussian distribution centered on 0.

Bottom Line: Specifically, we show that the effective auditory noise significantly increased tactile sensations of the finger, decreased luminance and contrast visual thresholds and significantly changed EMG recordings of the leg muscles during posture maintenance.We conclude that crossmodal SR is a ubiquitous phenomenon in humans that can be interpreted within an energy and frequency model of multisensory neurons spontaneous activity.The result is an integrated activation that promotes sensitivity transitions and the signals are then perceived.

View Article: PubMed Central - PubMed

Affiliation: Visual Psychophysics and Perception Laboratory, School of Optometry, University of Montreal, Montreal, Quebec, Canada.

ABSTRACT

Background: Stochastic resonance is a nonlinear phenomenon whereby the addition of noise can improve the detection of weak stimuli. An optimal amount of added noise results in the maximum enhancement, whereas further increases in noise intensity only degrade detection or information content. The phenomenon does not occur in linear systems, where the addition of noise to either the system or the stimulus only degrades the signal quality. Stochastic Resonance (SR) has been extensively studied in different physical systems. It has been extended to human sensory systems where it can be classified as unimodal, central, behavioral and recently crossmodal. However what has not been explored is the extension of this crossmodal SR in humans. For instance, if under the same auditory noise conditions the crossmodal SR persists among different sensory systems.

Methodology/principal findings: Using physiological and psychophysical techniques we demonstrate that the same auditory noise can enhance the sensitivity of tactile, visual and propioceptive system responses to weak signals. Specifically, we show that the effective auditory noise significantly increased tactile sensations of the finger, decreased luminance and contrast visual thresholds and significantly changed EMG recordings of the leg muscles during posture maintenance.

Conclusions/significance: We conclude that crossmodal SR is a ubiquitous phenomenon in humans that can be interpreted within an energy and frequency model of multisensory neurons spontaneous activity. Initially the energy and frequency content of the multisensory neurons' activity (supplied by the weak signals) is not enough to be detected but when the auditory noise enters the brain, it generates a general activation among multisensory neurons of different regions, modifying their original activity. The result is an integrated activation that promotes sensitivity transitions and the signals are then perceived. A physiologically plausible model for crossmodal stochastic resonance is presented.

Show MeSH
Related in: MedlinePlus