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somatosensory representation

Nobuo Kunori, Ichiro Takashima
The motor cortex of rats contains two forelimb motor areas; the caudal forelimb area (CFA) and the rostral forelimb area (RFA). Although the RFA is thought to correspond to the premotor and/or supplementary motor cortices of primates, which are higher-order motor areas that receive somatosensory inputs, it is unknown whether the RFA of rats receives somatosensory inputs in the same manner. To investigate this issue, voltage-sensitive dye (VSD) imaging was used to assess the motor cortex in rats following a brief electrical stimulation of the forelimb...
October 7, 2016: European Journal of Neuroscience
Irene Rembado, Elisa Castagnola, Luca Turella, Tamara Ius, Riccardo Budai, Alberto Ansaldo, Gian Nicola Angotzi, Francesco Debertoldi, Davide Ricci, Miran Skrap, Luciano Fadiga
High-density surface microelectrodes for electrocorticography (ECoG) have become more common in recent years for recording electrical signals from the cortex. With an acceptable invasiveness/signal fidelity trade-off and high spatial resolution, micro-ECoG is a promising tool to resolve fine task-related spatial-temporal dynamics. However, volume conduction - not a negligible phenomenon - is likely to frustrate efforts to obtain reliable and resolved signals from a sub-millimeter electrode array. To address this issue, we performed an independent component analysis (ICA) on micro-ECoG recordings of somatosensory-evoked potentials (SEPs) elicited by median nerve stimulation in three human patients undergoing brain surgery for tumor resection...
August 18, 2016: International Journal of Neural Systems
Malte R Schomers, Friedemann Pulvermüller
In the neuroscience of language, phonemes are frequently described as multimodal units whose neuronal representations are distributed across perisylvian cortical regions, including auditory and sensorimotor areas. A different position views phonemes primarily as acoustic entities with posterior temporal localization, which are functionally independent from frontoparietal articulatory programs. To address this current controversy, we here discuss experimental results from functional magnetic resonance imaging (fMRI) as well as transcranial magnetic stimulation (TMS) studies...
2016: Frontiers in Human Neuroscience
Hiroshi Yamada, Hiroaki Yaguchi, Saeka Tomatsu, Tomohiko Takei, Tomomichi Oya, Kazuhiko Seki
Proprioception is one's overall sense of the relative positions and movements of the various parts of one's body. The primary somatosensory cortex (SI) is involved in generating the proprioception by receiving peripheral sensory inputs from both cutaneous and muscle afferents. In particular, area 3a receives input from muscle afferents and areas 3b and 1 from cutaneous afferents. However, segregation of two sensory inputs to these cortical areas has not been evaluated quantitatively because of methodological difficulties in distinguishing the incoming signals...
2016: PloS One
Ruiqi Wu, Langting Su, Pai-Feng Yang, Li Min Chen
Reactivation of deafferented cortex plays a key role in mediating the recovery of lost functions, although the precise mechanism is not fully understood. This study simultaneously characterized the dynamic spatiotemporal features of tactile responses in areas 3b and 1 before and 6-8 weeks after partial dorsal column lesion (DCL), and examined how the reactivation relates to the recovery of simple hand use in squirrel monkeys. A combination of high spatiotemporal resolution functional intrinsic optical imaging, microelectrode mapping, behavioral assessment, and tracer histology methods were used...
September 2016: ENeuro
Ana Tajadura-Jiménez, Torsten Marquardt, David Swapp, Norimichi Kitagawa, Nadia Bianchi-Berthouze
Our mental representations of our body are continuously updated through multisensory bodily feedback as we move and interact with our environment. Although it is often assumed that these internal models of body-representation are used to successfully act upon the environment, only a few studies have actually looked at how body-representation changes influence goal-directed actions, and none have looked at this in relation to body-representation changes induced by sound. The present work examines this question for the first time...
2016: Frontiers in Psychology
Laure Mathevon, Nicolas Leroux, Céline Piscicelli, Emmanuelle Clarac, Shenhao Dai, Patrice Davoine, Paul Krack, Dominic Perennou
OBJECTIVE: To take care of postural disorders is a major issue in Parkinson's disease (PD). We present a documented observation suggesting the existence of a biased representation of verticality in PD, resulting in a severe retropulsion and recurrent falls. A rehabilitation program aimed to modulate verticality perception dramatically improved the postural perception of the vertical, trunk posture and balance abilities, and reduced retropulsion as well as lastingly fall frequency. OBSERVATIONS: A 68 year-old patient with Parkinson's disease fall backward 3 times a day...
September 2016: Annals of Physical and Rehabilitation Medicine
Laura K Case, David Brang, Rosalynn Landazuri, Pavitra Viswanathan, Vilayanur S Ramachandran
While most people take identification with their body for granted, conditions such as phantom limb pain, alien hand syndrome, and xenomelia suggest that the feeling of bodily congruence is constructed and susceptible to alteration. Individuals with xenomelia typically experience one of their limbs as over-present and aversive, leading to a desire to amputate the limb. Similarly, many transgender individuals describe their untreated sexed body parts as incongruent and aversive, and many experience phantom body parts of the sex they identify with (Ramachandran, 2008)...
September 19, 2016: Archives of Sexual Behavior
Meaghan S Adams, Christina Popovich, W Richard Staines
While there is evidence to show early enhancement of modality-specific somatosensory cortical event-related potentials (ERP) when two stimuli are task-relevant, less is understood about the cortical and behavioural correlates of early modality-specific sensory gating. This study sought to understand how attentional gating affects cortical processing of visual and tactile stimuli at early stages of modality-specific representation. Specifically, alterations in early somatosensory and visual processing based on attentional relevance were examined, along with the effect of an unattended sensory stimulus on cortical processing and behavioural performance...
September 15, 2016: Behavioural Brain Research
Per M Knutsen, Celine Mateo, David Kleinfeld
The ability to form an accurate map of sensory input to the brain is an essential aspect of interpreting functional brain signals. Here, we consider the somatotopic map of vibrissa-based touch in the primary somatosensory (vS1) cortex of mice. The vibrissae are represented by a Manhattan-like grid of columnar structures that are separated by inter-digitating septa. The development, dynamics and plasticity of this organization is widely used as a model system. Yet, the exact anatomical position of this organization within the vS1 cortex varies between individual mice...
October 5, 2016: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Roberto Vincis, Alfredo Fontanini
A growing body of literature has demonstrated that primary sensory cortices are not exclusively unimodal, but can respond to stimuli of different sensory modalities. However, several questions concerning the neural representation of cross-modal stimuli remain open. Indeed, it is poorly understood if cross-modal stimuli evoke unique or overlapping representations in a primary sensory cortex and whether learning can modulate these representations. Here we recorded single unit responses to auditory, visual, somatosensory, and olfactory stimuli in the gustatory cortex (GC) of alert rats before and after associative learning...
2016: ELife
Sanne Kikkert, James Kolasinski, Saad Jbabdi, Irene Tracey, Christian F Beckmann, Heidi Johansen-Berg, Tamar R Makin
The hand area of the primary somatosensory cortex contains detailed finger topography, thought to be shaped and maintained by daily life experience. Here we utilise phantom sensations and ultra high-field neuroimaging to uncover preserved, though latent, representation of amputees' missing hand. We show that representation of the missing hand's individual fingers persists in the primary somatosensory cortex even decades after arm amputation. By demonstrating stable topography despite amputation, our finding questions the extent to which continued sensory input is necessary to maintain organisation in sensory cortex, thereby reopening the question what happens to a cortical territory once its main input is lost...
August 23, 2016: ELife
Austin O Rosner, Steven M Barlow
We performed a functional near-infrared spectroscopy (fNIRS) study of the evoked hemodynamic responses seen in hand and face sensorimotor cortical representations during (1) active motor tasks and (2) pulsed pneumotactile stimulation. Contralateral fNIRS measurements were performed on 22 healthy adult participants using a block paradigm that consisted of repetitive right hand and right oral angle somatosensory stimulation using a pulsed pneumotactile array stimulator, and repetitive right-hand grip compression and bilabial compressions on strain gages...
August 22, 2016: Somatosensory & Motor Research
Tobias Katus, Martin Eimer
The maintenance of sensory information in working memory (WM) is mediated by the attentional activation of stimulus representations that are stored in perceptual brain regions. Using event-related potentials (ERPs), we measured tactile and visual contralateral delay activity (tCDA / CDA components) in a bimodal WM task to concurrently track the attention-based maintenance of information stored in anatomically segregated (somatosensory and visual) brain areas. Participants received tactile and visual sample stimuli on both sides, and in different blocks, memorized these samples on the same side or on opposite sides...
August 17, 2016: NeuroImage
Edith Chorev, Patricia Preston-Ferrer, Michael Brecht
The whisker trident, a three-whisker array on the rat's chin, has been implicated in egomotion sensing and might function as a tactile speedometer. Here we study the cortical representation of trident whiskers and E-row whiskers in barrel cortex. Neurons identified in trident cortex of anesthetized animals showed sustained velocity-sensitive responses to ground motion. In freely moving animals, about two-thirds of the units in the trident and E-row whisker cortices were tuned to locomotion speed, a larger fraction of speed-tuned cells than in the somatosensory dysgranular zone...
October 2016: Nature Neuroscience
Hui-Xin Qi, Feng Wang, Chia-Chi Liao, Robert M Friedman, Chaohui Tang, Jon H Kaas, Malcolm J Avison
After lesions of the somatosensory dorsal column (DC) pathway, the cortical hand representation can become unresponsive to tactile stimuli, but considerable responsiveness returns over weeks of post-lesion recovery. The reactivation suggests that preserved subthreshold sensory inputs become potentiated and axon sprouting occurs over time to mediate recovery. Here, we studied the recovery process in 3 squirrel monkeys, using high-resolution fMRI CBV-fMRI mapping of contralateral somatosensory cortex responsiveness to stimulation of distal finger pads with low and high level electrocutaneous stimulation (ES) before and 2, 4, and 6weeks after a high cervical level contralateral DC lesion...
August 11, 2016: NeuroImage
Emese Pálfi, Mária Ashaber, Cory Palmer, Robert M Friedman, Anna W Roe, László Négyessy
INTRODUCTION: The close functional relationship between areas 3b and 1 of the somatosensory cortex is based on their reciprocal connections indicating that tactile sensation depends on the interaction of these two areas. AIM: The aim of the authors was to explore this neuronal circuit at the level of the distal finger pad representation. METHOD: The study was made by bidirectional tract tracing aided by neurophysiological mapping in squirrel monkeys (Saimiri sciureus)...
August 2016: Orvosi Hetilap
Heather K Decot, Vijay Mk Namboodiri, Wei Gao, Jenna A McHenry, Joshua H Jennings, Sung-Ho Lee, Pranish A Kantak, Yu-ChiehJill Kao, Manasmita Das, Ilana B Witten, Karl Deisseroth, Yen-YuIan Shih, Garret D Stuber
Several neuropsychiatric conditions, such as addiction and schizophrenia may arise in part from dysregulated activity of ventral tegmental area dopaminergic (TH(VTA)) neurons, as well as from more global maladaptation in neurocircuit function. However, whether TH(VTA) activity affects large-scale brain-wide function remains unknown. Here, we selectively activated TH(VTA) neurons in transgenic rats and measured resulting changes in whole-brain activity using stimulus-evoked functional magnetic resonance imaging (fMRI)...
August 12, 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Keun-Tae Kim, Heung-Il Suk, Seong-Whan Lee
In this work, we propose a novel brain-controlled wheelchair, one of the major applications of brain-machine interfaces (BMIs), that allows an individual with mobility impairments to perform daily living activities independently. Specifically, we propose to use a steady-state somatosensory evoked potential (SSSEP) paradigm, which elicits brain responses to tactile stimulation of specific frequencies, for a user's intention to control a wheelchair. In our system, a user had three possible commands by concentrating on one of three vibration stimuli, which were attached to the left-hand, right-hand, and right-foot, to selectively control the wheelchair...
August 3, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Hyeong-Dong Park, Fosco Bernasconi, Javier Bello-Ruiz, Christian Pfeiffer, Roy Salomon, Olaf Blanke
UNLABELLED: Recent research has investigated self-consciousness associated with the multisensory processing of bodily signals (e.g., somatosensory, visual, vestibular signals), a notion referred to as bodily self-consciousness, and these studies have shown that the manipulation of bodily inputs induces changes in bodily self-consciousness such as self-identification. Another line of research has highlighted the importance of signals from the inside of the body (e.g., visceral signals) and proposed that neural representations of internal bodily signals underlie self-consciousness, which to date has been based on philosophical inquiry, clinical case studies, and behavioral studies...
August 10, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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