Although we use our visual and tactile sensory systems interchangeably for object recognition on a daily basis, little is known about the mechanism underlying this ability. This study examined how 3D shape features of objects form two... more
Although we use our visual and tactile sensory systems interchangeably for object recognition on a daily basis, little is known about the mechanism underlying this ability. This study examined how 3D shape features of objects form two congruent and interchangeable visual and tactile perceptual spaces in healthy male and female participants. Since active exploration plays an important role in shape processing, a virtual reality environment was used to visually explore 3D objects called digital embryos without using the tactile sense. In addition, during the tactile procedure, blindfolded participants actively palpated a 3D-printed version of the same objects with both hands. We first demonstrated that the visual and tactile perceptual spaces were highly similar. We then extracted a series of 3D shape features to investigate how visual and tactile exploration can lead to the correct identification of the relationships between objects. The results indicate that both modalities share th...
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<p>Mean values±SD of the gait parameters print area (A), lengths of the print (C), stride-lengths (B) and track-widths (D) for the young (black) and the aged rats (red), * p<0.01. (A+C): In contrast to the prints obtained from... more
<p>Mean values±SD of the gait parameters print area (A), lengths of the print (C), stride-lengths (B) and track-widths (D) for the young (black) and the aged rats (red), * p<0.01. (A+C): In contrast to the prints obtained from the forepaws (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0003399#pone-0003399-g004" target="_blank">Fig. 4</a>), the limb-specific parameters print area and the lengths of the prints of the hindpaw were significantly increased in old animals. (B+D): As in the forepaw (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0003399#pone-0003399-g004" target="_blank">Fig. 4</a>), for the global parameters we found decreasing stride-lengths and increasing track-widths for the hindpaw in the aged animals.</p
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Cognition and perception are closely coupled to alpha power, but whether there is a link between alpha power and perceptual learning efficacy is unknown. Here we show that somatosensory alpha power can be successfully up- and... more
Cognition and perception are closely coupled to alpha power, but whether there is a link between alpha power and perceptual learning efficacy is unknown. Here we show that somatosensory alpha power can be successfully up- and down-regulated with short-term neurofeedback training, which in turn controls subsequent tactile perceptual learning. We find that neurofeedback-induced increases in alpha power lead to enhanced learning, whereas reductions in alpha power impede learning. As a consequence, interindividual learning variability is substantially reduced. No comparable impact is observed for oscillatory power in theta, beta, and lower gamma frequency bands. Our results demonstrate that high pre-learning alpha levels are a requirement for reaching high learning efficiency. These data provide further evidence that alpha oscillations shape the functional architecture of the brain network by gating neural resources and thereby modulating levels of preparedness for upcoming processing.
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Research article Differential effects of tactile high- and low-frequency stimulation on tactile discrimination in human subjects
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Research Interests: Electrophysiology, Long Term Potentiation, Magnetic Resonance Imaging, Biology, Medicine, and 15 moreBiological Sciences, Brain Mapping, Brain, Humans, Cerebral Cortex, Male, Magnetics, Adult, Analysis of Variance, Indexation, Brain Function, Cortical Excitability, Functional Laterality, Medical and Health Sciences, and Electric stimulation
We report that the response of neurons in rat somatosensory cortex to tactile stimulation consists of two components, a short-latency response and an oscillatory response, observable as up to 8 peaks in the post-stimulus-time-histogram... more
We report that the response of neurons in rat somatosensory cortex to tactile stimulation consists of two components, a short-latency response and an oscillatory response, observable as up to 8 peaks in the post-stimulus-time-histogram with interpeak intervals in the order of 100 ms (10 Hz). While the first component is always stimulus locked, the second component is strictly stimulus-locked only when elicited from the resting state: once started, the oscillations are only weakly affected by further stimulation. This implies generally that the question of stimulus locking of oscillatory response components is not a yes/no question. Instead, the concept of dynamic coupling is shown to adequately capture the different limit cases. We present a simple dynamic model that exemplifies this point.
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Age-related changes occur on all stages of the human somatosensory pathway, thereby deteriorating tactile, haptic, and sensorimotor performance. However, recent studies show that age-related changes are not irreversible but treatable... more
Age-related changes occur on all stages of the human somatosensory pathway, thereby deteriorating tactile, haptic, and sensorimotor performance. However, recent studies show that age-related changes are not irreversible but treatable through peripheral stimulation paradigms based on neuroplasticity mechanisms. We here applied repetitive electric stimulation (rES) to the fingers on a bi-weekly basis for 4 weeks to induce enduring amelioration of age-related changes in healthy individuals aged 60-85 years. Tactile, haptic, and motor performance gradually improved over time of intervention. After termination of rES, tactile acuity recovered to baseline within 2 weeks, while the gains in haptic and motor performance were preserved for 2 weeks. Sham stimulation showed no comparable changes. Our data indicate that age-related decline of sensorimotor performance can be ameliorated by rES and can be stabilized by the repeated application. Thus, long-term application of rES appears as a prim...
Research Interests: Aging, Treatment Outcome, Movement disorders, Brain, Humans, and 15 moreDiscrimination Learning, Movement, Touch, Female, Male, Neuronal Plasticity, Neural plasticity, Aged, Touch Perception, Neural, Cognition disorders, Motor Skills, Psychomotor Performance, Neuropsychological Tests, and Electric stimulation
Copyright © 2011 Tobias Kalisch et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is... more
Copyright © 2011 Tobias Kalisch et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. As life expectancy continues to rise, in the future there will be an increasing number of older people prone to falling. Accordingly, there is an urgent need for comprehensive testing of older individuals to collect data and to identify possible risk factors for falling. Here we use a low-cost force platform to rapidly assess deficits in balance under various conditions. We tested 21 healthy older adults and 24 young adults during static stance, unidirectional and rotational displacement of their centre of pressure (COP). We found an age-related increase in postural sway during quiet standing and a reduction of maximal COP displacement in unidirectional and rotational displacement tests. Our data show that even low-cost computerized ...
We assume that the visual system serves for orientation in space, recognition of objects and the interpretation of scenes and scene sequences. This task breaks up into a series of partially interdependent subproblems which are solved by... more
We assume that the visual system serves for orientation in space, recognition of objects and the interpretation of scenes and scene sequences. This task breaks up into a series of partially interdependent subproblems which are solved by some 13–15 usually retinotopically organized areas. So far it has not been possible to correlate functions and areas unequivocally. One reason for this could be the inadequacy of the questions posed as a basis for experiments. However, we think it more likely that correlating a function with an area is, as a rule, inadmissible since the degree of the coupling in the whole system does not permit a simple divsion. Rather the type and degree of coupling determine the separation or integration of “elementary units”. It follows that co-operation between subsystems is an essential aspect. The data available to us from neurophysiological, neuroanatomic and behavioral physiological findings is insufficient to analyse such a system: they ensure neither the complete observability nor the complete controllability of the systems. So one is forced to use model comparison for analysis. Depending on the type of data, we use three models which complement each other to order the data and predict results which can be experimentally verified.
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The levels of the gonadal hormones estradiol and progesterone vary throughout the menstrual cycle thereby affecting cognition, emotion, mood, and social behaviour. However, how these hormones modulate the balance of neural excitation and... more
The levels of the gonadal hormones estradiol and progesterone vary throughout the menstrual cycle thereby affecting cognition, emotion, mood, and social behaviour. However, how these hormones modulate the balance of neural excitation and inhibition, which crucially regulate processing and plasticity, is not fully understood. We here used paired-pulse stimulation to investigate in healthy humans the action of low and high estradiol and progesterone on intracortical inhibition in somatosensory (SI) and visual cortex (V1). We found that paired-pulse suppression in both SI and VI depended on estradiol. During high estradiol levels, paired-pulse suppression was significantly reduced. No comparable effects were found for progesterone, presumably due to a confounding effect of estradiol. Also, no hormone level-depending effects were observed for single-pulse evoked SEPs (somatosensory evoked potentials) and VEPs (visual evoked potentials) indicating a specific hormonal action on intracorti...
Single cell receptive field dynamics characterized by highly complicated spatio-temporal activity distributions observable during sensory information processing transforms into much simpler spatio-temporal activity pattern at a population... more
Single cell receptive field dynamics characterized by highly complicated spatio-temporal activity distributions observable during sensory information processing transforms into much simpler spatio-temporal activity pattern at a population level, indicating a qualitative transformational step of time-variant processing from microscopic to mesoscopic levels. As these dynamics are subject to significant modifications during learning, dynamic information processing is in a permanent state of use-dependent fluctuations.
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Modified action, either artificially induced or occurring naturally during life-span, alters organization and processing of primary somatosensory cortex, thereby serving as a predictor of age-related changes. These findings, together with... more
Modified action, either artificially induced or occurring naturally during life-span, alters organization and processing of primary somatosensory cortex, thereby serving as a predictor of age-related changes. These findings, together with the interconnectedness between motor-sensory systems and temporally-distributed processing across hierarchical levels, throws into question a sharp division between early perception and cognition, and suggest that composite codes of perception and action might not be limited to higher areas.
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ZusammenfassungNeben direkter zentralnervöser Stimulation wie TMS oder tDCS und roboter- und gerätegestützter Rehabilitation wurden Therapieansätze basierend auf peripherer Stimulation entwickelt. Die bisher an Gesunden erhobenen Befunde... more
ZusammenfassungNeben direkter zentralnervöser Stimulation wie TMS oder tDCS und roboter- und gerätegestützter Rehabilitation wurden Therapieansätze basierend auf peripherer Stimulation entwickelt. Die bisher an Gesunden erhobenen Befunde deuten darauf hin, dass die repetitive sensorische Stimulation zu einer weitreichenden Reorganisation in den sensomotorischen Netzwerken führt. Die bisher publizierten Metastudien verweisen darauf, dass die alleinige oder in Kombination mit anderen Therapiemaßnahmen erfolgende Anwendung der peripheren Stimulation zu einem verbesserten Rehabilitationserfolg führt. Die Möglichkeit, die Stimulation zu Hause über lange Zeit anzuwenden zu können, dürfte gerade für die Langzeitbehandlung chronischer Patienten eine wichtige Rolle spielen.
Correlations between inherent, task-free low-frequency fluctuations in the blood oxygenation level-dependent (BOLD) signals of the brain provide a potent tool to delineate its functional architecture in terms of intrinsic functional... more
Correlations between inherent, task-free low-frequency fluctuations in the blood oxygenation level-dependent (BOLD) signals of the brain provide a potent tool to delineate its functional architecture in terms of intrinsic functional connectivity (iFC). Still, it remains unclear how iFC is modulated during learning. We employed whole-brain resting-state magnetic resonance imaging prior to and after training-independent repetitive sensory stimulation (rSS), which is known to induce somatosensory cortical reorganization. We investigated which areas in the sensorimotor network are susceptible to neural plasticity (i.e., where changes in functional connectivity occurred) and where iFC might be indicative of enhanced tactile performance. We hypothesized iFC to increase in those brain regions primarily receiving the afferent tactile input. Strengthened intrinsic connectivity within the sensorimotor network after rSS was found not only in the postcentral gyrus contralateral to the stimulate...
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Application of repetitive electrical stimulation (rES) of the fingers has been shown to improve tactile perception and sensorimotor performance in healthy individuals. To increase motor performance by priming the effects of active motor... more
Application of repetitive electrical stimulation (rES) of the fingers has been shown to improve tactile perception and sensorimotor performance in healthy individuals. To increase motor performance by priming the effects of active motor training (arm ability training; AAT) using rES. We compared the performance gain for the training increase of the averaged AAT tasks of both hands in two groups of strongly right-handed healthy volunteers. Functional Magnetic Resonance Imaging (fMRI) before and after AAT was assessed using three tasks for each hand separately: finger sequence tapping, visually guided grip force modulation, and writing. Performance during fMRI was controlled for preciseness and frequency. A total of 30 participants underwent a two-week unilateral left hand AAT, 15 participants with 20 minutes of rES priming of all fingertips of the trained hand, and 15 participants without rES priming. rES-primed AAT improved the trained left-hand performance across all training tasks...
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Many attempts are currently underway to restore age-related degraded perception, however, the link between restored perception and remodeled brain function remains elusive. To understand remodeling of age-related cortical reorganization... more
Many attempts are currently underway to restore age-related degraded perception, however, the link between restored perception and remodeled brain function remains elusive. To understand remodeling of age-related cortical reorganization we combined functional magnetic resonance imaging (fMRI) with assessments of tactile acuity, perceptual learning, and computational modeling. We show that aging leads to tactile degradation parallel to enhanced activity in somatosensory cortex. Using a neural field model we reconciled the empirical age-effects by weakening of cortical lateral inhibition. Using perceptual learning, we were able to partially restore tactile acuity, which however was not accompanied by the expected attenuation of cortical activity, but by a further enhancement. The neural field model reproduced these learning effects solely through a weakening of the amplitude of inhibition. These findings suggest that the restoration of age-related degraded tactile acuity on the cortic...
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We studied neural interactions by cross correlation analysis during representational plasticity induced by intracortical microstimulation (ICMS). Neuron pairs were simultaneously recorded in area 3b in adult New World monkeys, and in... more
We studied neural interactions by cross correlation analysis during representational plasticity induced by intracortical microstimulation (ICMS). Neuron pairs were simultaneously recorded in area 3b in adult New World monkeys, and in cortical field SI in adult rats. In normal animals, the degree of correlated spontaneous activity corresponded to the extent of receptive field overlap. After several hours of ICMS, the spatial extents of cortex over which correlated activity could be recorded was enlarged several-fold. Mapping experiments revealed that increased correlated activity was only recorded within that cortical sector that was representationally reorganized, indicating a close relationship between cortical reorganization and cooperative processes. Results support the hypothesis that discharge coincidence is crucial for the formation of functionally coupled neural groups, and implicate dynamically maintained groups in the genesis of postontogenetic plasticity.
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ABSTRACT
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Abstract: INTRODUCTIONWe propose evolutionary &amp;amp;quot;analysis by synthesis&amp;amp;quot;guided by neurobiological knowledge as a powerful toolin computational neuroscience. The challenge is toforce artificial evolution to... more
Abstract: INTRODUCTIONWe propose evolutionary &amp;amp;quot;analysis by synthesis&amp;amp;quot;guided by neurobiological knowledge as a powerful toolin computational neuroscience. The challenge is toforce artificial evolution to favor solutions that arereasonable from the biological point of view. Suchsolutions are only likely to evolve if as much neurobiologicalknowledge as possible is used in the designprocess. This can be achieved by providing su#cientexperimental data to evaluate
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Research Interests: Electrophysiology, Motion perception, Applied Animal Behavior, Electrocardiography, Cats, and 15 moreVisual Cortex, Brain, Female, Animals, CAT, Microelectrodes, Neurons, Single Cell, Perforation, Operant Conditioning, Signal to Noise Ratio, C/N Ratio, photic stimulation, Psychology and Cognitive Sciences, and Medical and Health Sciences
We investigated the pattern of glial fibrillary acidic protein (GFAP) and Wisteria floribunda agglutinin (WFA) labeled structures in the superior colliculus and in the somatosensory cortex of humans and rats of different age groups using... more
We investigated the pattern of glial fibrillary acidic protein (GFAP) and Wisteria floribunda agglutinin (WFA) labeled structures in the superior colliculus and in the somatosensory cortex of humans and rats of different age groups using immunohistochemical methods, light and confocal laser-scanning microscopy. We never found a double labeling of WFA and GFAP positive structures neither in the superior colliculus nor in the cortex of both man and rat. The complementary pattern of WFA and GFAP labeling was present both at the macroscopic and microscopic level. We found a clear prevalence of either WFA or GFAP expression in the arborization of the astrocytes as well as in the pattern of lamination.
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Paired-pulse behaviour in the somatosensory cortex is an approach to obtain insights into cortical processing modes and to obtain markers of changes of cortical excitability attributable to learning or pathological states. Numerous... more
Paired-pulse behaviour in the somatosensory cortex is an approach to obtain insights into cortical processing modes and to obtain markers of changes of cortical excitability attributable to learning or pathological states. Numerous studies have demonstrated suppression of the response to the stimulus that follows a first one after a short interval, but the underlying mechanisms remain elusive, although there is agreement that GABAergic mechanisms seem to play a crucial role. We therefore aimed to explore the influence of the GABAA agonist lorazepam on paired-pulse somatosensory evoked potentials (SEPs). We recorded and analysed SEPs after paired median nerve stimulation in healthy individuals before and after they had received a single dose of 2.5 mg of lorazepam as compared with a control group receiving placebo. Paired-pulse suppression was expressed as a ratio of the amplitudes of the second and the first peaks. We found that, after lorazepam application, paired-pulse suppression...
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In contrast to mechanisms mediating synaptic plasticity, the pharmacological basis of perceptual learning remains to be clarified. Here we report that a specific form of perceptual learning is influenced by GABAergic mechanisms. We... more
In contrast to mechanisms mediating synaptic plasticity, the pharmacological basis of perceptual learning remains to be clarified. Here we report that a specific form of perceptual learning is influenced by GABAergic mechanisms. We induced perceptual learning by Hebbian co-activation of the skin of the tip of the right index fingers in human subjects. Under placebo conditions, tactile 2-point discrimination was improved on the co-activated, but not on the left, index finger. This augmentation was completely eliminated by lorazepam, a GABAA receptor agonist. No drug effects were found on the left index finger indicating that the drugs had no effect per se on performance. The results demonstrate that perceptual learning is subject to pharmacological gating by basic mechanisms known to mediate and modulate synaptic plasticity.
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It is well established that permanent or transient reduction of somatosensory inputs, following hand deafferentation or anesthesia, induces plastic changes across the hand-face border, supposedly responsible for some altered perceptual... more
It is well established that permanent or transient reduction of somatosensory inputs, following hand deafferentation or anesthesia, induces plastic changes across the hand-face border, supposedly responsible for some altered perceptual phenomena such as tactile sensations being referred from the face to the phantom hand. It is also known that transient increase of hand somatosensory inputs, via repetitive somatosensory stimulation (RSS) at a fingertip, induces local somatosensory discriminative improvement accompanied by cortical representational changes in the primary somatosensory cortex (SI). We recently demonstrated that RSS at the tip of the right index finger induces similar training-independent perceptual learning across the hand-face border, improving somatosensory perception at the lips (Muret D, Dinse HR, Macchione S, Urquizar C, Farnè A, Reilly KT. Curr Biol 24: R736–R737, 2014). Whether neural plastic changes across the hand-face border accompany such remote and adaptive...
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Achieving perceptual gains in healthy individuals or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial... more
Achieving perceptual gains in healthy individuals or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial outcome similar to training can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation (rSS). For example, high-frequency repetitive sensory stimulation (HF-rSS) enhances tactile performance and induces cortical reorganization in healthy subjects and patients after stroke. Patients with complex regional pain syndrome (CRPS) show impaired tactile performance associated with shrinkage of cortical maps. We here investigated the feasibility and efficacy of HF-rSS, and low-frequency rSS (LF-rSS) to enhance tactile performance and reduce pain intensity in 20 patients with CRPS type I. Intermittent high- or low-frequency electrical stimuli were applied for 45 min/day to a...
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ABSTRACT
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Bodily training typically evokes behavioral and perceptual gains, enforcing neuroplastic processes and affecting neural representations. We investigated the effect on somatosensory perception of a three-day Zen meditation exercise, a... more
Bodily training typically evokes behavioral and perceptual gains, enforcing neuroplastic processes and affecting neural representations. We investigated the effect on somatosensory perception of a three-day Zen meditation exercise, a purely mental intervention. Tactile spatial discrimination of the right index finger was persistently improved by only 6 hours of mental-sensory focusing on this finger, suggesting that intrinsic brain activity created by mental states can alter perception and behavior similarly to external stimulation.