Noise defined as random disturbances is ubiquitous in both the external environment and the nervo... more Noise defined as random disturbances is ubiquitous in both the external environment and the nervous system. Depending on the context, noise can degrade or improve information processing and performance. In all cases, it contributes to neural systems dynamics. We review some effects of various sources of noise on the neural processing of self-motion signals at different stages of the vestibular pathways and the resulting perceptual responses. Hair cells in the inner ear reduce the impact of noise by means of mechanical and neural filtering. Hair cells synapse on regular and irregular afferents. Variability of discharge (noise) is low in regular afferents and high in irregular units. The high variability of irregular units provides information about the envelope of naturalistic head motion stimuli. A subset of neurons in the vestibular nuclei and thalamus are optimally tuned to noisy motion stimuli that reproduce the statistics of naturalistic head movements. In the thalamus, variabil...
ABSTRACTNoisy galvanic vestibular stimulation has been shown to improve vestibular perception in ... more ABSTRACTNoisy galvanic vestibular stimulation has been shown to improve vestibular perception in healthy subjects. Here, we sought to obtain similar results using more natural stimuli consisting of small-amplitude motion perturbations of the whole body. Thirty participants were asked to report the perceived direction of antero-posterior sinusoidal motion on a MOOG platform. We compared the baseline perceptual thresholds with those obtained by applying small, stochastic perturbations at different power levels along the antero-posterior axis, symmetrically distributed around a zero-mean. At the population level, we found that the thresholds for all but the highest level of noise were significantly lower than the baseline threshold. At the individual level, the threshold was lower with at least one noise level than the threshold without noise in 87% of participants. Thus, small, stochastic oscillations of the whole body can increase the probability of detecting subthreshold vestibular ...
<p>A: Distribution histogram of the responses (pooled over participants). B: CDFs for each ... more <p>A: Distribution histogram of the responses (pooled over participants). B: CDFs for each participant and for the population. Same format as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093020#pone-0093020-g002" target="_blank">Figure 2B</a>.</p
Raw data related to "Visuomotor Interactions and Perceptual Judgments in Virtual Reality Sim... more Raw data related to "Visuomotor Interactions and Perceptual Judgments in Virtual Reality Simulating Different Levels of Gravity"
X and Y raw centroid and tail positions of individual Drosophila melanogaster larvae (n=41) in th... more X and Y raw centroid and tail positions of individual Drosophila melanogaster larvae (n=41) in the dispersal condition (foraging in the absence of olfactory cues) tracked at 7Hz and at the spatial resolution specified in the file— see manuscript for more details
We report the discovery that the locomotor trajectories of <i>Drosophila</i> larvae f... more We report the discovery that the locomotor trajectories of <i>Drosophila</i> larvae follow the power-law relationship between speed and curvature previously found in the movements of human and non-human primates. Using high-resolution behavioural tracking in controlled but naturalistic sensory environments, we tested the law in maggots tracing different trajectory types, from reaching-like movements to scribbles. For most but not all flies, we found that the law holds robustly, with an exponent close to third-fourth rather than to the usual two-third found in almost all human situations, suggesting dynamic effects adding on purely kinematic constraints. There are different hypotheses for the origin of the law in primates, one invoking cortical computations, another viscoelastic muscle properties coupled with central pattern generators. Our findings are consistent with the latter view and demonstrate that the law is possible in animals with nervous systems orders of magnitude simpler than in primates. Scaling laws might exist, because natural selection favours processes that remain behaviourally efficient across a wide range of neural and body architectures in distantly related species.
Gravity is a physical constraint all terrestrial species have adapted to through evolution. Indee... more Gravity is a physical constraint all terrestrial species have adapted to through evolution. Indeed, gravity effects are taken into account in many forms of interaction with the environment, from the seemingly simple task of maintaining balance to the complex motor skills performed by athletes and dancers. Graviceptors, primarily located in the vestibular otolith organs, feed the Central Nervous System with information related to the gravity acceleration vector. This information is integrated with signals from semicircular canals, vision, and proprioception in an ensemble of interconnected brain areas, including the vestibular nuclei, cerebellum, thalamus, insula, retroinsula, parietal operculum, and temporo-parietal junction, in the so-called vestibular network. Classical views consider this stage of multisensory integration as instrumental to sort out conflicting and/or ambiguous information from the incoming sensory signals. However, there is compelling evidence that it also contr...
The power function A(t)=kC(t)^beta was fitted to the results of the larvae in the overshoot condi... more The power function A(t)=kC(t)^beta was fitted to the results of the larvae in the overshoot condition, after filtering the raw x, y position samples of the centroid at the frequency cutoff indicated on the abscissae. Nofilt denotes no filter whatsoever. Summary boxplot statistics are plotted for the beta-exponent (a) and r^2 (b). Outliers are orange dots.
Noise defined as random disturbances is ubiquitous in both the external environment and the nervo... more Noise defined as random disturbances is ubiquitous in both the external environment and the nervous system. Depending on the context, noise can degrade or improve information processing and performance. In all cases, it contributes to neural systems dynamics. We review some effects of various sources of noise on the neural processing of self-motion signals at different stages of the vestibular pathways and the resulting perceptual responses. Hair cells in the inner ear reduce the impact of noise by means of mechanical and neural filtering. Hair cells synapse on regular and irregular afferents. Variability of discharge (noise) is low in regular afferents and high in irregular units. The high variability of irregular units provides information about the envelope of naturalistic head motion stimuli. A subset of neurons in the vestibular nuclei and thalamus are optimally tuned to noisy motion stimuli that reproduce the statistics of naturalistic head movements. In the thalamus, variabil...
ABSTRACTNoisy galvanic vestibular stimulation has been shown to improve vestibular perception in ... more ABSTRACTNoisy galvanic vestibular stimulation has been shown to improve vestibular perception in healthy subjects. Here, we sought to obtain similar results using more natural stimuli consisting of small-amplitude motion perturbations of the whole body. Thirty participants were asked to report the perceived direction of antero-posterior sinusoidal motion on a MOOG platform. We compared the baseline perceptual thresholds with those obtained by applying small, stochastic perturbations at different power levels along the antero-posterior axis, symmetrically distributed around a zero-mean. At the population level, we found that the thresholds for all but the highest level of noise were significantly lower than the baseline threshold. At the individual level, the threshold was lower with at least one noise level than the threshold without noise in 87% of participants. Thus, small, stochastic oscillations of the whole body can increase the probability of detecting subthreshold vestibular ...
<p>A: Distribution histogram of the responses (pooled over participants). B: CDFs for each ... more <p>A: Distribution histogram of the responses (pooled over participants). B: CDFs for each participant and for the population. Same format as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093020#pone-0093020-g002" target="_blank">Figure 2B</a>.</p
Raw data related to "Visuomotor Interactions and Perceptual Judgments in Virtual Reality Sim... more Raw data related to "Visuomotor Interactions and Perceptual Judgments in Virtual Reality Simulating Different Levels of Gravity"
X and Y raw centroid and tail positions of individual Drosophila melanogaster larvae (n=41) in th... more X and Y raw centroid and tail positions of individual Drosophila melanogaster larvae (n=41) in the dispersal condition (foraging in the absence of olfactory cues) tracked at 7Hz and at the spatial resolution specified in the file— see manuscript for more details
We report the discovery that the locomotor trajectories of <i>Drosophila</i> larvae f... more We report the discovery that the locomotor trajectories of <i>Drosophila</i> larvae follow the power-law relationship between speed and curvature previously found in the movements of human and non-human primates. Using high-resolution behavioural tracking in controlled but naturalistic sensory environments, we tested the law in maggots tracing different trajectory types, from reaching-like movements to scribbles. For most but not all flies, we found that the law holds robustly, with an exponent close to third-fourth rather than to the usual two-third found in almost all human situations, suggesting dynamic effects adding on purely kinematic constraints. There are different hypotheses for the origin of the law in primates, one invoking cortical computations, another viscoelastic muscle properties coupled with central pattern generators. Our findings are consistent with the latter view and demonstrate that the law is possible in animals with nervous systems orders of magnitude simpler than in primates. Scaling laws might exist, because natural selection favours processes that remain behaviourally efficient across a wide range of neural and body architectures in distantly related species.
Gravity is a physical constraint all terrestrial species have adapted to through evolution. Indee... more Gravity is a physical constraint all terrestrial species have adapted to through evolution. Indeed, gravity effects are taken into account in many forms of interaction with the environment, from the seemingly simple task of maintaining balance to the complex motor skills performed by athletes and dancers. Graviceptors, primarily located in the vestibular otolith organs, feed the Central Nervous System with information related to the gravity acceleration vector. This information is integrated with signals from semicircular canals, vision, and proprioception in an ensemble of interconnected brain areas, including the vestibular nuclei, cerebellum, thalamus, insula, retroinsula, parietal operculum, and temporo-parietal junction, in the so-called vestibular network. Classical views consider this stage of multisensory integration as instrumental to sort out conflicting and/or ambiguous information from the incoming sensory signals. However, there is compelling evidence that it also contr...
The power function A(t)=kC(t)^beta was fitted to the results of the larvae in the overshoot condi... more The power function A(t)=kC(t)^beta was fitted to the results of the larvae in the overshoot condition, after filtering the raw x, y position samples of the centroid at the frequency cutoff indicated on the abscissae. Nofilt denotes no filter whatsoever. Summary boxplot statistics are plotted for the beta-exponent (a) and r^2 (b). Outliers are orange dots.
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