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

Schellekens, Wouter; Bakker, Carlijn; Nf, Ramsey; Petridou, Natalia

doi:10.1101/2020.11.12.379339

Cited by 2 publications

(3 citation statements)

References 97 publications

(122 reference statements)

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“…In addition, recent reports in rodents show that the information content arising from different tactile inputs provided to a digit, could be decoded even from a non-adjacent digit representation (Enander and Jörntell, 2019). This and other recent evidence (Tommerdahl, Favorov and Whitsel, 2010; Thakur, Fitzgerald and Hsiao, 2012; Schellekens et al ., 2020; Wesselink et al ., 2020) stress the need to investigate the distribution of representational information content throughout S1 homunculus.…”

Section: Introductionsupporting

confidence: 89%

Beyond body maps: information content of specific body parts is distributed across the somatosensory Homunculus

Muret

Root

Kieliba

et al. 2021

Preprint

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The somatosensory homunculus in primary somatosensory cortex (S1) is topographically organised, with relatively high selectivity to each body part in its primary area. This dominant feature may eclipse other organising principles in S1. Recent multivariate methodologies allow us to identify representational features beyond selectivity, e.g., information content, providing new opportunities to characterise the homunculus. Using Representational Similarity Analysis, we asked whether body part information content can be identified in S1 beyond the primary area of a given body part. Representational dissimilarities in fMRI activity patterns were compared between different body parts (face, hand and feet) and subparts (e.g., fingers), and between different actions performed with the same body part. Throughout the S1 homunculus, we identified significant dissimilarities between non-primary body parts (e.g., between the hand and the lips in the foot area). We also observed significant dissimilarities between body subparts in distant non-primary areas (e.g., different face parts in the foot area). Finally, we could significantly dissociate between two movements performed by one body part (e.g., the hand) well beyond its primary area (e.g., in the foot and face areas), even when focusing the analysis along the most topographically organised sub-region of S1, Brodmann area 3b. Altogether, our results demonstrate that body part and action-related information content is more distributed across S1 homunculus than previously considered. While this finding does not revoke the general topographic organising principle of S1, it reveals yet unexplored underlying information contents that could be harnessed for rehabilitation, as well as novel brain-machine interfaces.

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Section: Introductionsupporting

confidence: 89%

Beyond body maps: information content of specific body parts is distributed across the somatosensory Homunculus

Muret

Root

Kieliba

et al. 2021

Preprint

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“…A subset of participants also showed partial or full somatotopic representations in BAs 3a and/or 4p, in the fundus or anterior bank of the central sulcus. Somatotopic representations in these locations have been reported previously, in response to both passive tactile stimulation (Saadon-Grosman et al, 2020b) and active movements (Schellekens et al, 2018(Schellekens et al, , 2020. However, these studies have not examined the possibility that they could be an artefact due to extravascular BOLD contributions or imperfect registration between functional and anatomical MRI data, as our data seem to suggest.…”

Section: Preferred Fingertipsmentioning

confidence: 44%

“…1). Somatotopic representation in the anterior bank or fundus of the central sulcus have been reported previously, in response to either passive tactile stimulation of different body parts (Saadon-Grosman et al, 2020b) or active movements of the limbs or fingers (Schellekens et al, 2018(Schellekens et al, , 2020. None of these studies however examined the possibility that these pre-central somatotopic representations could be due to imperfect registration between functional and anatomical MRI data.…”

Section: Fingertip Prf Measurements In Primary Somatosensory Cortexmentioning

confidence: 97%

Fast event-related mapping of population fingertip tuning properties in human sensorimotor cortex at 7T

Khalifé

Francis

Schluppeck

et al. 2022

Preprint

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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.

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

Cited by 2 publications

References 97 publications

Beyond body maps: information content of specific body parts is distributed across the somatosensory Homunculus

Beyond body maps: information content of specific body parts is distributed across the somatosensory Homunculus

Fast event-related mapping of population fingertip tuning properties in human sensorimotor cortex at 7T

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