scholarly journals Somatosensory Cortex Efficiently Processes Touch Located Beyond the Body

2019 ◽  
Vol 29 (24) ◽  
pp. 4276-4283.e5 ◽  
Author(s):  
Luke E. Miller ◽  
Cécile Fabio ◽  
Valeria Ravenda ◽  
Salam Bahmad ◽  
Eric Koun ◽  
...  
1997 ◽  
Vol 17 (16) ◽  
pp. 6338-6351 ◽  
Author(s):  
Paul R. Manger ◽  
Timothy M. Woods ◽  
Alberto Muñoz ◽  
Edward G. Jones

Science ◽  
1979 ◽  
Vol 204 (4392) ◽  
pp. 521-523 ◽  
Author(s):  
J. Kaas ◽  
R. Nelson ◽  
M Sur ◽  
C. Lin ◽  
M. Merzenich

Neuron ◽  
2017 ◽  
Vol 94 (5) ◽  
pp. 985-992 ◽  
Author(s):  
Michael Brecht

2000 ◽  
Vol 355 (1394) ◽  
pp. 267-273 ◽  
Author(s):  
Yoshiaki Iwamura

Earlier studies recording single neuronal activity with bilateral receptive fields in the primary somatosensory cortex of monkeys and cats agreed that the bilateral receptive fields were related exclusively to the body midline and that the ipsilateral information reaches the cortex via callosal connections since they are dense in the cortical region representing the midline structures of the body while practically absent in the regions representing the distal extremities. We recently found a substantial number of neurons with bilateral receptive fields on hand digits, shoulders–arms or legs–feet in the caudalmost part (areas 2 and 5) of the postcentral gyrus in awake Japanese monkeys ( Macaca fuscata ). I review these results, discuss the functional implications of this bilateral representation in the postcentral somatosensory cortex from a behavioural standpoint and give a new interpretation to the midline fusion theory.


2021 ◽  
Vol 14 ◽  
Author(s):  
W. R. Willoughby ◽  
Kristina Thoenes ◽  
Mark Bolding

Functional magnetic resonance imaging (fMRI) was used to estimate neuronal activity in the primary somatosensory cortex of six participants undergoing cutaneous tactile stimulation on skin areas spread across the entire body. Differences between the accepted somatotopic maps derived from Penfield's work and those generated by this fMRI study were sought, including representational transpositions or replications across the cortex. MR-safe pneumatic devices mimicking the action of a Wartenberg wheel supplied touch stimuli in eight areas. Seven were on the left side of the body: foot, lower, and upper leg, trunk beneath ribcage, anterior forearm, middle fingertip, and neck above the collarbone. The eighth area was the glabella. Activation magnitude was estimated as the maximum cross-correlation coefficient at a certain phase shift between ideal time series and measured blood oxygen level dependent (BOLD) time courses on the cortical surface. Maximally correlated clusters associated with each cutaneous area were calculated, and cortical magnification factors were estimated. Activity correlated to lower limb stimulation was observed in the paracentral lobule and superomedial postcentral region. Correlations to upper extremity stimulation were observed in the postcentral area adjacent to the motor hand knob. Activity correlated to trunk, face and neck stimulation was localized in the superomedial one-third of the postcentral region, which differed from Penfield's cortical homunculus.


Author(s):  
A. D. (Bud) Craig

This chapter looks at the experiments that demonstrated in monkeys and humans the unforeseen lamina I pathway to the thalamus and its subsequent projection to the interoceptive cortex. The ascending interoceptive thalamocortical pathway is phylogenetically unique to primates; it most likely arose in conjunction with the enormous encephalization associated with the emergence of the primate lineage. The existence of this pathway was a surprise to most investigators in the field of somatosensory neurobiology. As mentioned in chapter 1, a sensory representation of general feelings from the body had been envisioned by the German natural philosophers of the nineteenth century. However, that concept was superseded by the heuristic codification of nociception and the assignment of pain and temperature sensations to the somatosensory cortex. The chapter's findings rectify that misconception and substantiate the fundamental neurobiological distinction between interoception and exteroception at the thalamocortical level in the monkey and human.


Author(s):  
Reubs Walsh ◽  
Gillian Einstein

The policing of boundaries of acceptable sexual identities and behaviour is a recurring theme in numerous marginalities. Gender (especially womanhood) is often instantiated socially through the harms to which members of that gender are subjected. For transgender people, the assumption that genitals define gender translates the ubiquitous misapprehension that genitals and sex are binary into an assumption that gender must also be binary. This circumscribes the potentiality of cultural intelligibility for trans gender identities, and may interfere with the ability of transgender people to select the most appropriate medical and social means of expressing their authentic identities, even altering what is possible or appropriate, thereby curtailing trans people’s authenticity and freedom. We therefore distinguish social from bodily aspects of gender dysphoria, proposing a model of their distinct, intersecting origins. We explore ways in which transgender medicine reflects aspects of other gendered surgeries, proposing a biopsychosocial understanding of embodiment, including influences of culture on the neurological representation of the body in the somatosensory cortex. This framework proposes that cultural cissexism, causes trans people to experience (neuro)physiological damage, creating or exacerbating the need for medical transition within a framework of individual autonomy. Our social-constructionist feminist neuroscientific account of gendered embodiment highlights the medical necessity of bodily autonomy for trans people seeking surgery or other biomedical interventions, and the ethical burden therein.


1995 ◽  
Vol 73 (4) ◽  
pp. 1537-1546 ◽  
Author(s):  
N. Jain ◽  
S. L. Florence ◽  
J. H. Kaas

1. To better understand the limits and extents of plasticity in sensory systems of adult mammals, we unilaterally sectioned the dorsal funiculus at thoracic levels in nine adult rats to deactivate ascending afferents from the hindpaw and lower body. After postsurgical recovery periods of 3 h to 3 mo, the region of primary somatosensory cortex (S1) representing the limbs and trunk was extensively mapped with microelectrodes. 2. Recording sites were later identified as being within the hindlimb representation and other parts of S1 by relating locations of microlesions to the cytochrome oxidase pattern in sections of cortex cut tangential to the pial surface. The extent and effectiveness of spinal cord lesions were evaluated by injecting cholera toxin B subunit conjugated with horseradish peroxidase (B-HRP) at various sites in the deafferented hindpaw. 3. In five animals with complete section of the dorsal funiculus, we failed to detect any response to cutaneous stimulation of any part of the body in the deafferented hindlimb cortex. In four other animals with incomplete lesions, neurons in some penetrations could be activated by hindlimb stimulation, but not by stimulating other body parts. In those cases without activation of hindlimb cortex, B-HRP was detected in the spinal cord only caudal to the lesion, and it was not transported to the nucleus gracilis. Limited transport past the lesion to nucleus gracilis was detected in cases with incomplete lesions. 4. The results indicate that forelimb inputs do not substitute for missing hindlimb inputs in primary somatosensory cortex in rats and that the potential for somatotopic reorganization is more limited than previously thought.


Leonardo ◽  
2020 ◽  
pp. 1-8
Author(s):  
Haven Wright ◽  
Preston Foerder

The somatosensory homunculus shows a deformed human figure that illustrates the proportion of the brain devoted to the sense of touch in each part of the body. Originally based on Penfield’s brain mapping, it has been presented as a drawing of a human figure along the somatosensory cortex, an independent human figure, and a sculpted figure. Until recently, these homunculi have been male due to the lack of information on the female somatosensory cortex. A few female homunculi have been drawn. Based on more current brain research, the authors present, to our knowledge, the first sculpted 3D female somatosensory homunculus.


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