scholarly journals Investigating facial information content in the hand area of individuals with a congenital and acquired missing hand

2021 ◽  
Author(s):  
Victoria Root ◽  
Dollyane Muret ◽  
Maite Arribas ◽  
Elena Amoruso ◽  
John Thornton ◽  
...  

Cortical remapping after hand loss in the primary somatosensory cortex (S1) is thought to be predominantly dictated by cortical proximity, with adjacent body parts remapping into the deprived area. Traditionally, this remapping has been characterised by changes in the lip representation, which is assumed to be the immediate neighbour of the hand based on electrophysiological research in non-human primates. However, the orientation of facial somatotopy in humans is debated, with contrasting work reporting both an inverted and upright topography. We aimed to fill this gap in the S1 homunculus by investigating the topographic organisation of the face. Using both univariate and multivariate approaches we examined the extent of face-to-hand remapping in individuals with a congenital and acquired missing hand (hereafter one-handers and amputees, respectively), relative to two-handed controls. Participants were asked to move different facial parts (forehead, nose, lips, tongue) during fMRI scanning. We first report evidence for an upright facial organisation in all three groups, with the upper face and not the lips bordering the hand area. We further found little evidence for remapping of all tested facial parts in amputees, with no significant relationship to the chronicity of their PLP. In contrast, we found converging evidence for a complex pattern of face remapping in congenital one-handers across all facial parts, where the location of the cortical neighbour, the forehead, is shown to shift away from the deprived hand area, which is subsequently activated by the lips and the tongue. Together, our findings demonstrate that the face representation in humans is highly plastic, but that this plasticity is restricted by the developmental stage of input deprivation, rather than cortical proximity.

1993 ◽  
Vol 79 (6) ◽  
pp. 874-884 ◽  
Author(s):  
Gregory McCarthy ◽  
Truett Allison ◽  
Dennis D. Spencer

✓ The authors describe a method of localizing the sensory and motor peri-rolandic cortex representing the face and intraoral structures. Somatosensory evoked potentials (SEP's) to stimulation of the chin, lips, tongue, and palate were recorded in 37 patients studied intraoperatively under general anesthesia or following chronic implantation of cortical surface electrodes. Localization by trigeminal SEP recording was validated by SEP localization of the hand area with median nerve stimulation, and by cortical stimulation of the hand and face areas. The following conclusions were drawn regarding the implementation of face area localization: 1) in general agreement with the results of cortical stimulation in humans and single-unit recordings in monkeys, there is a medial-to-lateral representation in somatosensory cortex of the hand, chin, upper lip, lower lip, tongue, and palate; 2) the chin and lip representations overlap, are adjacent to the hand area, and provide little additional localizing information if the hand area has been identified; 3) stimulation of the tongue and palate evokes reliable, large-amplitude SEP's useful for localization; 4) palatal SEP's allow localization near the sylvian sulcus; 5) for any type of trigeminal stimulation, the largest SEP's are recorded from the somatosensory cortex and provide the most consistent criterion for its identification; and 6) polarity inversion of potentials across the sulcus (a reliable localizing criterion for median nerve SEP's) is a less reliable criterion for trigeminal SEP's.


2007 ◽  
Vol 97 (1) ◽  
pp. 200-207 ◽  
Author(s):  
Alexander M. Benison ◽  
David M. Rector ◽  
Daniel S. Barth

This study used high-resolution hemispheric mapping of somatosensory evoked potentials to determine the number and organization of secondary somatosensory areas (SII) in rat cortex. Two areas, referred to as SII and PV (parietoventral), revealed complete (SII) or nearly complete (PV) body maps. The vibrissa and somatic representation of SII was upright, rostrally oriented, and immediately lateral to primary somatosensory cortex (SI), with a dominant face representation. Vibrissa representations in SII were highly organized, with the rows staggered rostrally along the mediolateral axis. Area PV was approximately one fifth the size of SII, and located rostral and lateral to auditory cortex. PV had a rostrally oriented and inverted body representation that was dominated by the distal extremities, with little representation of the face or vibrissae. These data support the conclusion that in the rat, as in other species, SII and PV represent anatomically and functionally distinct areas of secondary somatosensory cortex.


2009 ◽  
Vol 30 (3) ◽  
pp. 757-765 ◽  
Author(s):  
Eric A. Moulton ◽  
Gautam Pendse ◽  
Susie Morris ◽  
Matthew Aiello-Lammens ◽  
Lino Becerra ◽  
...  

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Christiaan P. J. de Kock ◽  
Jean Pie ◽  
Anton W. Pieneman ◽  
Rebecca A. Mease ◽  
Arco Bast ◽  
...  

AbstractDiversity of cell-types that collectively shape the cortical microcircuit ensures the necessary computational richness to orchestrate a wide variety of behaviors. The information content embedded in spiking activity of identified cell-types remain unclear to a large extent. Here, we recorded spike responses upon whisker touch of anatomically identified excitatory cell-types in primary somatosensory cortex in naive, untrained rats. We find major differences across layers and cell-types. The temporal structure of spontaneous spiking contains high-frequency bursts (≥100 Hz) in all morphological cell-types but a significant increase upon whisker touch is restricted to layer L5 thick-tufted pyramids (L5tts) and thus provides a distinct neurophysiological signature. We find that whisker touch can also be decoded from L5tt bursting, but not from other cell-types. We observed high-frequency bursts in L5tts projecting to different subcortical regions, including thalamus, midbrain and brainstem. We conclude that bursts in L5tts allow accurate coding and decoding of exploratory whisker touch.


Author(s):  
Laura Mora ◽  
Anna Sedda ◽  
Teresa Esteban ◽  
Gianna Cocchini

AbstractThe representation of the metrics of the hands is distorted, but is susceptible to malleability due to expert dexterity (magicians) and long-term tool use (baseball players). However, it remains unclear whether modulation leads to a stable representation of the hand that is adopted in every circumstance, or whether the modulation is closely linked to the spatial context where the expertise occurs. To this aim, a group of 10 experienced Sign Language (SL) interpreters were recruited to study the selective influence of expertise and space localisation in the metric representation of hands. Experiment 1 explored differences in hands’ size representation between the SL interpreters and 10 age-matched controls in near-reaching (Condition 1) and far-reaching space (Condition 2), using the localisation task. SL interpreters presented reduced hand size in near-reaching condition, with characteristic underestimation of finger lengths, and reduced overestimation of hands and wrists widths in comparison with controls. This difference was lost in far-reaching space, confirming the effect of expertise on hand representations is closely linked to the spatial context where an action is performed. As SL interpreters are also experts in the use of their face with communication purposes, the effects of expertise in the metrics of the face were also studied (Experiment 2). SL interpreters were more accurate than controls, with overall reduction of width overestimation. Overall, expertise modifies the representation of relevant body parts in a specific and context-dependent manner. Hence, different representations of the same body part can coexist simultaneously.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yunjun Nam ◽  
Takayuki Sato ◽  
Go Uchida ◽  
Ekaterina Malakhova ◽  
Shimon Ullman ◽  
...  

AbstractHumans recognize individual faces regardless of variation in the facial view. The view-tuned face neurons in the inferior temporal (IT) cortex are regarded as the neural substrate for view-invariant face recognition. This study approximated visual features encoded by these neurons as combinations of local orientations and colors, originated from natural image fragments. The resultant features reproduced the preference of these neurons to particular facial views. We also found that faces of one identity were separable from the faces of other identities in a space where each axis represented one of these features. These results suggested that view-invariant face representation was established by combining view sensitive visual features. The face representation with these features suggested that, with respect to view-invariant face representation, the seemingly complex and deeply layered ventral visual pathway can be approximated via a shallow network, comprised of layers of low-level processing for local orientations and colors (V1/V2-level) and the layers which detect particular sets of low-level elements derived from natural image fragments (IT-level).


1998 ◽  
Vol 06 (03) ◽  
pp. 265-279 ◽  
Author(s):  
Shimon Edelman

The paper outlines a computational approach to face representation and recognition, inspired by two major features of biological perceptual systems: graded-profile overlapping receptive fields, and object-specific responses in the higher visual areas. This approach, according to which a face is ultimately represented by its similarities to a number of reference faces, led to the development of a comprehensive theory of object representation in biological vision, and to its subsequent psychophysical exploration and computational modeling.


2019 ◽  
Vol 121 (1) ◽  
pp. 152-162 ◽  
Author(s):  
Nicholas Paul Holmes ◽  
Luigi Tamè

Transcranial magnetic stimulation (TMS) over human primary somatosensory cortex (S1), unlike over primary motor cortex (M1), does not produce an immediate, objective output. Researchers must therefore rely on one or more indirect methods to position the TMS coil over S1. The “gold standard” method of TMS coil positioning is to use individual functional and structural magnetic resonance imaging (f/sMRI) alongside a stereotactic navigation system. In the absence of these facilities, however, one common method used to locate S1 is to find the scalp location that produces twitches in a hand muscle (e.g., the first dorsal interosseus, M1-FDI) and then move the coil posteriorly to target S1. There has been no systematic assessment of whether this commonly reported method of finding the hand area of S1 is optimal. To do this, we systematically reviewed 124 TMS studies targeting the S1 hand area and 95 fMRI studies involving passive finger and hand stimulation. Ninety-six TMS studies reported the scalp location assumed to correspond to S1-hand, which was on average 1.5–2 cm posterior to the functionally defined M1-hand area. Using our own scalp measurements combined with similar data from MRI and TMS studies of M1-hand, we provide the estimated scalp locations targeted in these TMS studies of the S1-hand. We also provide a summary of reported S1 coordinates for passive finger and hand stimulation in fMRI studies. We conclude that S1-hand is more lateral to M1-hand than assumed by the majority of TMS studies.


2017 ◽  
Vol 69 (2) ◽  
pp. 293-298 ◽  
Author(s):  
M. Lazăr ◽  
O.C. Iacob ◽  
C. Solcan ◽  
S.A. Pașca ◽  
R. Lazăr ◽  
...  

ABSTRACT Investigations of four roe deer corpses were carried out from May until October 2014, in the Veterinary Forensic Laboratory and in the Parasitic Diseases Clinic, in the Iasi Faculty of Veterinary Medicine. The roe deer were harvested by shooting during the trophy hunting season. The clinical examination of the shot specimens revealed the presence of a highly consistent number of extremely mobile apterous insects, spread on the face, head, neck, lateral body parts, abdominal regions, inguinal, perianal and, finally, all over the body. The corpses presented weakening, anemia and cutaneous modification conditions. Several dozen insects were prelevated in a glass recipient and preserved in 70º alcoholic solution in order to identify the ectoparasite species. The morphological characteristics included insects in the Diptera order, Hippoboscidae family, Lipoptena cervi species. These are highly hematophagous insects that by severe weakening are affecting the game health and trophy quality. Histological investigations of the skin revealed some inflammatory reactions caused by ectoparasite Lipoptena cervi. Lipoptena cervi was identified for the first time in Iasi County, Romania.


OPSI ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 6
Author(s):  
Rossi Septy Wahyuni ◽  
Eko Nursubiyantoro ◽  
Gina Awaliah

Helmet is a product that is generally used when riding a motorcycle, the function of the helmet is to protect body parts especially the head when accident while driving. Many of helmet product still have deficiency both in terms of form of function, in this case helmet products still have any problems in their function. The shape of the helmet that is already on the market does not pay attention to the needs of the community if the helmet is exposed to rain when stored in the outdoor. The planning and development of helmet products is then processed using Quality Function Development (QFD). The customer need regarding customer products are half face shaped helmet, full face shaped helmet, flip up shaped helmet, lightweight helmet shell materials, strong helmet shell materials, strong helmet locking locks, visor material is not easily scratched, visor material is not easily broken, visor material is not easily to blur, foam helmet is easily to clean, foam helmet is soft, foam helmet is not easily to moldy, cloth helmet is soft on the face, helmet cloth is easily to absorb sweat, cloth helmet is not easy to smell, helmet lock is easy to install, helmet in solid colour, helmet with patterned appearance, and helmet there are added feature waterproof. The technical characteristics of helmet product are the type of the shell material, the shape of the shell, the weight of the shell, the colour of the shell, the type of visor material, the colour of the visor, the type of foam material, the type of fabric material, the type of locking material, and additional features of waterproof helmet. The specification of the proposed helmet are the type of shell material in the form of ABS plastic, the shape of the helmet is half face, the weight of the helmet is 2 kg, the colour of the helmet is solid (black), the type of the visor is polycarbonate, the colour of the visor is transparent, the type of material foam is polystyrene, the type of fabric is the velor fabric, the type of locking material is quick release buckle, and additional feature are waterproof in the form of cover of taslan fabric.


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