To what extent does functional brain organization rely on sensory input? Here, we show that for the penultimate visual-processing region, ventral-temporal cortex (VTC), visual experience is not the origin of its fundamental organizational property, category selectivity. In the fMRI study reported here, we presented 14 congenitally blind participants with face-, body-, scene-, and object-related natural sounds and presented 20 healthy controls with both auditory and visual stimuli from these categories. Using macroanatomical alignment, response mapping, and surface-based multivoxel pattern analysis, we demonstrated that VTC in blind individuals shows robust discriminatory responses elicited by the four categories and that these patterns of activity in blind subjects could successfully predict the visual categories in sighted controls. These findings were confirmed in a subset of blind participants born without eyes and thus deprived from all light perception since conception. The sounds also could be decoded in primary visual and primary auditory cortex, but these regions did not sustain generalization across modalities. Surprisingly, although not as strong as visual responses, selectivity for auditory stimulation in visual cortex was stronger in blind individuals than in controls. The opposite was observed in primary auditory cortex. Overall, we demonstrated a striking similarity in the cortical response layout of VTC in blind individuals and sighted controls, demonstrating that the overall category-selective map in extrastriate cortex develops independently from visual experience.ategory selectivity in human and primate visual cortex is a striking example of how the brain encodes the outer world. Mostly found on the lateral and ventral parts of the temporal lobe, several distinct macroscopic brain regions are known to have a preference for a particular category of visual objects, including faces [fusiform face area, occipital face area (1)], body parts [extrastriate body area (2), fusiform body area (3)], artificial objects [lateral occipital complex (4)], and scenes [parahippocampal place area (5)]. The exact computational mechanisms that drive these regions are still largely unknown: Do these regions operate as distinct functional modules (1, 6), or is category selectivity fully distributed across ventral-temporal cortex (VTC) (7), ora combination of both-do category-selective regions reflect peaks in a broad tuning map for visual object features (8)?A prominent question is whether this functional architecture develops independently of visual input or relies on visual experience during early infancy and the following years. As an example of the latter, a key hypothesis indicates that the global functional organization of VTC starts out as a protomap with a retinotopic layout (9-11). Through visual experience, regions within this protomap develop selectivity for the visual categories that often appear in the retinotopic region that is represented. According to this perspective, because faces most likely appear...

The present experiment addressed the time course of corticospinal excitability changes following interventional muscle tendon vibration. Using transcranial magnetic stimulation, motor evoked potentials of the flexor carpi radialis and extensor carpi radialis brevis muscle were recorded for a period of 60 min after cessation of vibration (80 Hz, 0.5 mm, 30 min) to the distal wrist flexor tendons. A delayed corticospinal excitability increase in both the vibrated and non-vibrated antagonistic muscle was observed, with lasting levels of facilitation for the latter. No changes were observed following interventional cutaneous vibration. These results underscore a facilitatory influence of prolonged Ia-afferent activation on corticospinal excitability. Findings are discussed in light of recent advances in promoting motor recovery after brain injury by somatosensory stimulation.

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The lower areas of the hierarchically organized visual cortex are strongly retinotopically organized, with strong responses to specific retinotopic stimuli, and no response to other stimuli outside these preferred regions. Higher areas in the ventral occipitotemporal cortex show a weak eccentricity bias, and are mainly sensitive for object category (e.g., faces versus buildings). This study investigated how the mapping of eccentricity and category sensitivity using functional magnetic resonance imaging is affected by a retinal lesion in two very different low vision patients: a patient with a large central scotoma, affecting central input to the retina (juvenile macular degeneration), and a patient where input to the peripheral retina is lost (retinitis pigmentosa). From the retinal degeneration, we can predict specific losses of retinotopic activation. These predictions were confirmed when comparing stimulus activations with a no-stimulus fixation baseline. At the same time, however, seemingly contradictory patterns of activation, unexpected given the retinal degeneration, were observed when different stimulus conditions were directly compared. These unexpected activations were due to position-specific deactivations, indicating the importance of investigating absolute activation (relative to a no-stimulus baseline) rather than relative activation (comparing different stimulus conditions). Data from two controls, with simulated scotomas that matched the lesions in the two patients also showed that retinotopic mapping results could be explained by a combination of activations at the stimulated locations and deactivations at unstimulated locations. Category sensitivity was preserved in the two patients. In sum, when we take into account the full pattern of activations and deactivations elicited in retinotopic cortex and throughout the ventral object vision pathway in low vision patients, the pattern of (de)activation is consistent with the retinal loss.