scholarly journals Fast event-related mapping of fingertip population receptive fields in human somatosensory and motor cortex

2022 ◽  
Author(s):  
Sarah Khalife ◽  
Susan T. Francis ◽  
Denis Schluppeck ◽  
Rosa-Maria Sanchez-Panchuelo ◽  
Julien Besle
Keyword(s):  
Receptive Fields ◽  
7 Tesla ◽  
Body Parts ◽  
Stimulus Interval ◽  
Human Cortex ◽  
Body Representations ◽  
Robust Estimates ◽  
Tuning Width ◽  
Brodmann Areas ◽  
Central Gyrus

The majority of fMRI studies investigating somatotopic body representations in the human cortex have used either block or phase-encoding stimulation designs. Event-related (ER) designs allow for more natural and flexible stimulation sequences, while enabling the independent estimation of responses to different body parts in the same cortical location. Here we compared an efficiency-optimized fast ER design (2s inter stimulus interval, ISI) to a slow ER design (8s ISI) for mapping fingertip voxelwise tuning properties in the sensorimotor cortex of 6 participants at 7 Tesla. The fast ER design resulted in similar, but more robust, estimates compared to the slow ER design. Concatenating the fast and slow ER data, we demonstrate in each individual brain the existence of two separate somatotopically-organized representations of the fingertips, one in S1 on the post-central gyrus and the other at the border of the motor and pre-motor cortices on the pre-central gyrus. In both post-central and pre-central representations, fingertip tuning width increases progressively, from narrowly-tuned Brodmann areas 3b and 4a respectively, towards parietal and frontal regions responding equally to all fingertips.

scholarly journals Non-informative vision improves spatial tactile discrimination on the shoulder but does not influence detection sensitivity

2020 ◽  
Vol 238 (12) ◽  
pp. 2865-2875
Author(s):  
Fabrizio Leo ◽  
Sara Nataletti ◽  
Luca Brayda
Keyword(s):  
Tactile Stimulation ◽  
Detection Threshold ◽  
Receptive Fields ◽  
Judgment Task ◽  
The Body ◽  
Detection Sensitivity ◽  
Body Parts ◽  
Tactile Acuity ◽  
Tactile Stimuli ◽  
Numerosity Judgment

Abstract Vision of the body has been reported to improve tactile acuity even when vision is not informative about the actual tactile stimulation. However, it is currently unclear whether this effect is limited to body parts such as hand, forearm or foot that can be normally viewed, or it also generalizes to body locations, such as the shoulder, that are rarely before our own eyes. In this study, subjects consecutively performed a detection threshold task and a numerosity judgment task of tactile stimuli on the shoulder. Meanwhile, they watched either a real-time video showing their shoulder or simply a fixation cross as control condition. We show that non-informative vision improves tactile numerosity judgment which might involve tactile acuity, but not tactile sensitivity. Furthermore, the improvement in tactile accuracy modulated by vision seems to be due to an enhanced ability in discriminating the number of adjacent active electrodes. These results are consistent with the view that bimodal visuotactile neurons sharp tactile receptive fields in an early somatosensory map, probably via top-down modulation of lateral inhibition.

scholarly journals Moving in on human motor cortex. Characterizing the relationship between body parts with non-rigid population Response Fields

2020 ◽  
Author(s):  
Wouter Schellekens ◽  
Carlijn Bakker ◽  
Nick F. Ramsey ◽  
Natalia Petridou
Keyword(s):  
Ring Finger ◽  
Body Part ◽  
7 Tesla ◽  
Whole Body ◽  
Body Parts ◽  
Population Response ◽  
Human Motor Cortex ◽  
Neuronal Populations ◽  
Cortical Motor ◽  
The Relationship

AbstractFor cortical motor activity, the relationships between different body part representations is unknown. Through reciprocal body part relationships, functionality of cortical motor areas with respect to whole body motor control can be characterized. In the current study, we investigate the relationship between body part representations within individual neuronal populations in motor cortices, following a 7 Tesla fMRI 18-body-part motor experiment in combination with our newly developed non-rigid population Response Field (pRF) model and graph theory. The non-rigid pRF metrics reveal somatotopic structures in all included motor cortices covering frontal, parietal, medial and insular cortices and that neuronal populations in primary sensorimotor cortex respond to fewer body parts than secondary motor cortices. Reciprocal body part relationships are estimated in terms of uniqueness, clique-formation, and importance. We report unique response profiles for the knee, a clique of body parts surrounding the ring finger, and a central role for the shoulder and wrist. These results reveal associations among body parts from the perspective of the central nervous system, while being in agreement with intuitive notions of body part usage.

scholarly journals Gulliver’s virtual travels: active embodiment in extreme body sizes for modulating our body representations

2020 ◽  
Vol 21 (4) ◽  
pp. 509-520
Author(s):  
S. Serino ◽  
F. Scarpina ◽  
A. Chirico ◽  
A. Dakanalis ◽  
D. Di Lernia ◽  
...  
Keyword(s):  
Body Image ◽  
Virtual Environment ◽  
Perceptual Experience ◽  
Reference Condition ◽  
Body Parts ◽  
Body Dimensions ◽  
Body Representations ◽  
Multisensory Stimulation ◽  
Action Capabilities ◽  
Body Sizes

AbstractIt is noted that the perceptual experience of body and space can be modulated by changing the action capabilities or by manipulating the perceived body dimensions through a multisensory stimulation. This study adds to pre-existing literature by investigating the alterations in bodily experience following embodiment to both enlarged and shrunked bodies, while participants actively navigated in a virtual environment. A normal-sized body served as a reference condition. After each embodied navigation, participants estimated the height and width of three different body parts. Results revealed that the embodiment over shrunked body induced a significant reduction in participants’ body image, while no changes were reported after the embodiment over the enlarged body. Findings were discussed in terms of previous literature exploring the constraints implicated in the ownership over different bodies.

Reorganization in the Cutaneous Core of the Human Thalamic Principal Somatic Sensory Nucleus (Ventral Caudal) in Patients With Dystonia

1999 ◽  
Vol 82 (6) ◽  
pp. 3204-3212 ◽  
Author(s):  
Fred A. Lenz ◽  
Nancy N. Byl
Keyword(s):  
Essential Tremor ◽  
Average Length ◽  
Receptive Fields ◽  
Body Part ◽  
The Body ◽  
Sensory Cortex ◽  
Body Parts ◽  
Primary Sensory Cortex ◽  
Wide Range ◽  
Sensory Nucleus

A wide range of observations suggest that sensory inputs play a significant role in dystonia. For example, the map of the hand representation in the primary sensory cortex (area 3b) is altered in monkeys with dystonia-like movements resulting from overtraining in a gripping task. We investigated whether similar reorganization occurs in the somatic sensory thalamus of patients with dystonia (dystonia patients). We studied recordings of neuronal activity and microstimulation-evoked responses from the cutaneous core of the human principal somatic sensory nucleus (ventral caudal, Vc) of 11 dystonia patients who underwent stereotactic thalamotomy. Fifteen patients with essential tremor who underwent similar procedures were used as controls. The cutaneous core of Vc was defined as the part of the cellular thalamic region where the majority of cells had receptive fields (RFs) to innocuous cutaneous stimuli. The proportion of RFs including multiple parts of the body was greater in dystonia patients (29%) than in patients with essential tremor (11%). Similarly, the percentage of projected fields (PFs) including multiple body parts was higher in dystonia patients (71%) than in patients with essential tremor (41%). A match at a thalamic site was said to occur if the RF and PF at that site included a body part in common. Such matches were significantly less prevalent in dystonia patients (33%) than in patients with essential tremor (58%). The average length of the trajectory where the PF included a consistent, cutaneous RF was significantly longer in patients with dystonia than in control patients with essential tremor. The findings of sensory reorganization in Vc thalamus are congruent with those reported in the somatic sensory cortex of monkeys with dystonia-like movements resulting from overtraining in a gripping task.

What is the body schema?

2021 ◽  
pp. 3-17
Author(s):  
Frédérique de Vignemont ◽  
Victor Pitron ◽  
Adrian J. T. Alsmith
Keyword(s):  
Motor Control ◽  
Body Schema ◽  
General Term ◽  
The Body ◽  
Body Parts ◽  
Detailed Characterization ◽  
Body Representations ◽  
Local Body

The body schema is commonly defined as the representation of a body for action. But what do we mean exactly by that? What makes the body schema so special? The type of information that it represents? The way this information is represented? Or the function of the representation? And is there more than one type of body schema? There is a sense indeed in which the term ‘body schema’ is ambiguous, in that it functions as a general term that groups together various body representations intervening at different stages in motor control, representing short- or long-term properties, used for positive or negative affordances. In addition, one might want to distinguish between local body schemata, which represent body parts, and a global body schema, which represents the body as a whole. But is this latter holistic representation really necessary? Here this chapter will present a detailed characterization of the manifold of representational processes involved in what we commonly refer to as the body schema, as well as the key mechanisms that contribute to their construal.

scholarly journals Patterns of multisensory facilitation distinguish peripersonal from reaching space

2020 ◽  
Author(s):  
A. Zanini ◽  
I. Patané ◽  
E. Blini ◽  
R. Salemme ◽  
E. Koun ◽  
...  
Keyword(s):  
Receptive Fields ◽  
Theoretical Models ◽  
Body Part ◽  
Peripersonal Space ◽  
The Body ◽  
Theoretical Issue ◽  
Hand Position ◽  
Body Parts ◽  
Arm Reaching ◽  
Whole Space

AbstractPeripersonal space is a multisensory representation of the space near body parts facilitating interactions with the close environment. Studies on non-human and human primates converge in showing that peripersonal space (PPS) is a body-part-centred representation that guides actions. Because of these characteristics, growing confusion conflates peripersonal and arm-reaching space (ARS) that is the space one’s arm can reach. Despite neuroanatomical evidence favors their distinction, whether PPS and ARS tap into different spatial representations remains poorly understood. Here, in five experiments we found that PPS differs from ARS in male and female human participants (N = 120), as evidenced both by their performance and the modeling of their multisensory facilitation. We mapped multisensory facilitation in detecting touches at the hand, placed in different locations radially within ARS. Results showed that 1) PPS is smaller than ARS; 2) multivariate modeling of spatial patterns of multisensory facilitation predicts well the position of the participants’ hand within ARS; 3) multisensory facilitation maps shift according to changes of hand position, revealing hand-centred coding of PPS, but not ARS; and 4) cross-correlation analyses highlight isomorphic multisensory facilitation maps across hand positions, suggesting their functional similarity to the receptive fields of monkeys’ multisensory neurons. In sharp contrast, ARS mapping produced undistinguishable patterns across hand positions, cross-validating the conclusion that PPS and ARS are distinct. These findings call for a refinement of theoretical models of PPS and ARS, which are relevant in constructs as diverse as action and self representation, (social) interpersonal distance, brain-machine interfaces and neuroprosthetics.Significance StatementThe peripersonal space (PPS) is a multisensory interface allowing us to interact with objects in the space close to our body-parts, playing a fundamental role for the defense of the body and for the motor control of actions. Recent research has conflated PPS with the arm-reaching space (ARS), that is whole space reachable by the arm. However, there is actually no evidence supporting this equivalence and the anatomical and functional differences between PPS and ARS have been largely overlooked. In this paper, we frame the theoretical issue in depth, validate a novel methodological paradigm across five experiments, and eventually report robust and cross-validated evidence for the distinction between PPS and ARS, supported by both multivariate and univariate analyses.

scholarly journals Evidence for Integrated Visual Face and Body Representations in the Anterior Temporal Lobes

2016 ◽  
Vol 28 (8) ◽  
pp. 1178-1193 ◽  
Author(s):  
Bronson B. Harry ◽  
Katja Umla-Runge ◽  
Andrew D. Lawrence ◽  
Kim S. Graham ◽  
Paul E. Downing
Keyword(s):  
Neural Coding ◽  
Temporal Cortex ◽  
Whole Body ◽  
Unexpected Finding ◽  
Body Parts ◽  
Strong Response ◽  
Body Representations ◽  
Temporal Lobes ◽  
Anterior Temporal Lobes ◽  
The Right

Research on visual face perception has revealed a region in the ventral anterior temporal lobes, often referred to as the anterior temporal face patch (ATFP), which responds strongly to images of faces. To date, the selectivity of the ATFP has been examined by contrasting responses to faces against a small selection of categories. Here, we assess the selectivity of the ATFP in humans with a broad range of visual control stimuli to provide a stronger test of face selectivity in this region. In Experiment 1, participants viewed images from 20 stimulus categories in an event-related fMRI design. Faces evoked more activity than all other 19 categories in the left ATFP. In the right ATFP, equally strong responses were observed for both faces and headless bodies. To pursue this unexpected finding, in Experiment 2, we used multivoxel pattern analysis to examine whether the strong response to face and body stimuli reflects a common coding of both classes or instead overlapping but distinct representations. On a voxel-by-voxel basis, face and whole-body responses were significantly positively correlated in the right ATFP, but face and body-part responses were not. This finding suggests that there is shared neural coding of faces and whole bodies in the right ATFP that does not extend to individual body parts. In contrast, the same approach revealed distinct face and body representations in the right fusiform gyrus. These results are indicative of an increasing convergence of distinct sources of person-related perceptual information proceeding from the posterior to the anterior temporal cortex.

Many areas in the human brain respond to visual motion

1994 ◽  
Vol 72 (3) ◽  
pp. 1420-1424 ◽  
Author(s):  
P. Dupont ◽  
G. A. Orban ◽  
B. De Bruyn ◽  
A. Verbruggen ◽  
L. Mortelmans
Keyword(s):  
Human Brain ◽  
Visual Motion ◽  
Emission Tomography ◽  
Position Emission Tomography ◽  
Activation Technique ◽  
Human Cortex ◽  
Visual Areas ◽  
Brodmann Areas ◽  
Dot Density ◽  
Random Dot Pattern

1. The regions of the human brain responsive to motion were mapped using the H2(15)O position emission tomography (PET) activation technique and compared by viewing a moving random dot pattern with a stationary dot pattern. The stimulus was optimized in dot density and 3 degrees in diameter. 2. In addition to bilateral foci at the border between Brodmann areas 19 and 37, a V1/V2 focus and a focus in the cuneus reported earlier, we observed activations in other visual areas (lower BA 19 and the parieto-occipital fissure) in the cerebellum and in two other, presumed vestibular areas, the posterior bank of lateral sulcus and at the border of BA 2/40. 3. Homologies between monkey and human cortex are discussed.

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