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Arithmetic reasoning activates the occipital cortex of congenitally blind people (CB). This activation of visual areas may highlight the functional flexibility of occipital regions deprived of their dominant inputs or relate to the intrinsic computational role of specific occipital regions. We contrasted these competing hypotheses by characterizing the brain activity of CB and sighted participants while performing subtraction, multiplication and a control letter task. In both groups, subtraction selectively activated a bilateral dorsal network commonly activated during spatial processing. Multiplication triggered activity in temporal regions thought to participate in memory retrieval. No between-group difference was observed for the multiplication task whereas subtraction induced enhanced activity in the right dorsal occipital cortex of the blind individuals only. As this area overlaps with regions showing selective tuning to auditory spatial processing and exhibits increased functional connectivity with a dorsal "spatial" network, our results suggest that the recruitment of occipital regions during high-level cognition in the blind actually relates to the intrinsic computational role of the activated regions.

Localizing touch relies on the activation of skin-based and externally defined spatial frames of reference. Psychophysical studies have demonstrated that early visual deprivation prevents the automatic remapping of touch into external space. We used fMRI to characterize how visual experience impacts the brain circuits dedicated to the spatial processing of touch. Sighted and congenitally blind humans performed a tactile temporal order judgment (TOJ) task, either with the hands uncrossed or crossed over the body midline. Behavioral data confirmed that crossing the hands has a detrimental effect on TOJ judgments in sighted but not in early blind people. Crucially, the crossed hand posture elicited enhanced activity, when compared with the uncrossed posture, in a frontoparietal network in the sighted group only. Psychophysiological interaction analysis revealed, however, that the congenitally blind showed enhanced functional connectivity between parietal and frontal regions in the crossed versus uncrossed hand postures. Our results demonstrate that visual experience scaffolds the neural implementation of the location of touch in space. In daily life, we seamlessly localize touch in external space for action planning toward a stimulus making contact with the body. For efficient sensorimotor integration, the brain has therefore to compute the current position of our limbs in the external world. In the present study, we demonstrate that early visual deprivation alters the brain activity in a dorsal parietofrontal network typically supporting touch localization in the sighted. Our results therefore conclusively demonstrate the intrinsic role that developmental vision plays in scaffolding the neural implementation of touch perception.

The main goal of this study was to test the hypothesis that disorders in entrainment to the beat of music originate from motor deficits. To this aim, we adapted the Beat Alignment Test and tested a large pool of control subjects, as well as nine individuals who had previously showed deficits in synchronization to the beat of music. The tasks consisted of tapping (Experiment 1) and bouncing (Experiment 2) in synchrony with the beat of non-classical music that varied in genre, tempo, and groove, and then judging whether a superimposed metronome was perceived as on or off the beat of the same selection of music. Results indicate concomitant deficits in both beat synchronization and the detection of misalignment with the beat, supporting the hypothesis that the motor system is implicated in beat perception.

Objective Primary motor (M1) cortical excitability alterations are involved in the development and maintenance of chronic pain. Less is known about M1-cortical excitability implications in the acute phase of an orthopedic trauma. This study aims to assess acute M1-cortical excitability in patients with an isolated upper limb fracture (IULF) in relation to pain intensity. Methods Eighty-four (56 IULF patients <14 days post-trauma and 28 healthy controls). IULF patients were divided into two subgroups according to pain intensity (mild versus moderate to severe pain). A single transcranial magnetic stimulation (TMS) session was performed over M1 to compare groups on resting motor threshold (rMT), short-intracortical inhibition (SICI), intracortical facilitation (ICF), and long-interval cortical inhibition (LICI). Results Reduced SICI and ICF were found in IULF patients with moderate to severe pain, whereas mild pain was not associated with M1 alterations. Age, sex, and time since the accident had no influence on TMS measures. Discussion These findings show altered M1 in the context of acute moderate to severe pain, suggesting early signs of altered GABAergic inhibitory and glutamatergic facilitatory activities.

Localizing touch relies on the activation of skin-based and externally defined spatial frames of references. Psychophysical studies have demonstrated that early visual deprivation prevents the automatic remapping of touch into external space. We used fMRI to characterize how visual experience impacts on the brain circuits dedicated to the spatial processing of touch. Sighted and congenitally blind humans (male and female) performed a tactile temporal order judgment (TOJ) task, either with the hands uncrossed or crossed over the body midline. Behavioral data confirmed that crossing the hands has a detrimental effect on TOJ judgments in sighted but not in blind. Crucially, the crossed hand posture elicited more activity in a fronto-parietal network in the sighted group only. Psychophysiological interaction analysis revealed that the congenitally blind showed enhanced functional connectivity between parietal and frontal regions in the crossed versus uncrossed hand postures. Our results demonstrate that visual experience scaffolds the neural implementation of touch perception.Significance statementAlthough we seamlessly localize tactile events in our daily life, it is not a trivial operation because the hands move constantly within the peripersonal space. To process touch correctly, the brain has therefore to take the current position of the limbs into account and remap them to their location in the external world. In sighted, parietal and premotor areas support this process. However, while visual experience has been suggested to support the implementation of the automatic external remapping of touch, no studies so far have investigated how early visual deprivation alters the brain network supporting touch localization. Examining this question is therefore crucial to conclusively determine the intrinsic role vision plays in scaffolding the neural implementation of touch perception.

Recruitment of occipital cortex by arithmetic processing follows computational bias in early 3 blind 4 Abstract 22Arithmetic reasoning activates the occipital cortex of early blind people (EB). This activation 23 of visual areas may reflect functional flexibility or the intrinsic computational role of specific 24 occipital regions. We contrasted these competing hypotheses by characterizing the brain 25 activity of EB and sighted participants while performing subtraction, multiplication and a 26 control verbal task. In both groups, subtraction selectively activated a bilateral dorsal network 27 commonly activated during spatial processing. Multiplication triggered more activity in 28 temporal regions thought to participate in memory retrieval. No between-group difference 29 was observed for the multiplication task whereas subtraction induced enhanced activity in the 30 right dorsal occipital cortex of the blind individuals only. As this area overlaps and exhibits 31 increased functional connectivity with regions showing selective tuning to auditory spatial 32 processing, our results suggest that the recruitment of occipital regions during high-level 33 cognition in the blind actually relates to the intrinsic computational role of the reorganized 34 regions. 35 36 37 38 7 CB (see Figure 1 and Table 1). Interestingly and as shown in Figure 2, part of this region also 130 shows selective tuning to auditory spatial processing in the blind (7). The opposite contrast 131 ([SC > CB] [subtraction > multiplication]) did not yield any significant effect. 132Multiplication. There was common multiplication related activity in SC and CB ([SC Ç 133 CB] [multiplication > subtraction]) in the right Superior Temporal Gyrus (STG) (see Figure 1 134 and Table 1). Neither the contrast ([CB > SC] [multiplication > subtraction]), nor the contrast 135 ([SC > CB] [multiplication > subtraction]) yielded significant effects. 136 Functional connectivity. We found increased correlations between the left MOG and 137 Results were thresholded at p<0.001 at the voxel level and FDR-corrected p<0.05 at the 381 cluster level. 382 383 Acknowledgments 384The authors are grateful to Giulia Dormal for her help in implementing the design of this 385 study.

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