This minireview describes recent advances in high-tech innovations on virtual reality (VR) aiding physical and cognitive recovery from neuromuscular disorders, notably useful for post-stroke rehabilitation. VR is a computer-generated technique that engulfs users in 3D multisensory interactive feedback. This technique creates simulations of realistic situations that can be manipulated by a user. It provides a spectrum of benefits in both physical and cognitive rehabilitation in the wake of neuromuscular episodes. VR engages and motivates patients to endure the unpleasant sequela of disease. Further, it enhances the acquisition of rehabilitative skills by caregivers and trains them in psychophysical health preservation. The benefits and user-friendliness of VR make it an increasingly welcome assistive neurological therapy tool. However, VR standardization, mechanisms, and, particularly, the long-term effects appear not to keep pace with its popularity and fast-progressing technical advances. Evidence-based studies on large groups of individuals are needed to settle these issues.

• MeSH
• Humans MeSH
• Neuromuscular Diseases * rehabilitation   psychology   physiopathology   MeSH
• Recovery of Function MeSH
• Stroke Rehabilitation * methods   MeSH
• Virtual Reality * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

The dorsal and ventral visual streams have been considered to play distinct roles in visual processing for action: the dorsal stream is assumed to support real-time actions, while the ventral stream facilitates memory-guided actions. However, recent evidence suggests a more integrated function of these streams. We investigated the neural dynamics and functional connectivity between them during memory-guided actions using intracranial EEG. We tracked neural activity in the inferior parietal lobule in the dorsal stream, and the ventral temporal cortex in the ventral stream as well as the hippocampus during a delayed action task involving object identity and location memory. We found increased alpha power in both streams during the delay, indicating their role in maintaining spatial visual information. In addition, we recorded increased alpha power in the hippocampus during the delay, but only when both object identity and location needed to be remembered. We also recorded an increase in theta band phase synchronization between the inferior parietal lobule and ventral temporal cortex and between the inferior parietal lobule and hippocampus during the encoding and delay. Granger causality analysis indicated dynamic and frequency-specific directional interactions among the inferior parietal lobule, ventral temporal cortex, and hippocampus that varied across task phases. Our study provides unique electrophysiological evidence for close interactions between dorsal and ventral streams, supporting an integrated processing model in which both streams contribute to memory-guided actions.

• Keywords
• Alpha oscillations, Dorsal visual stream, Granger causality analysis, Intracranial EEG, Memory-guided actions, Phase-locking value, Theta oscillations, Ventral visual stream,
• MeSH
• Adult MeSH
• Electroencephalography MeSH
• Electrocorticography MeSH
• Hippocampus * physiology   MeSH
• Humans MeSH
• Young Adult MeSH
• Memory * physiology   MeSH
• Temporal Lobe * physiology   MeSH
• Parietal Lobe * physiology   MeSH
• Visual Perception * physiology   MeSH
• Visual Pathways * physiology   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Spatial reference frames (RFs) play a key role in spatial cognition, especially in perception, spatial memory, and navigation. There are two main types of RFs: egocentric (self-centered) and allocentric (object-centered). Although many fMRI studies examined the neural correlates of egocentric and allocentric RFs, they could not sample the fast temporal dynamics of the underlying cognitive processes. Therefore, the interaction and timing between these two RFs remain unclear. Taking advantage of the high temporal resolution of intracranial EEG (iEEG), we aimed to determine the timing of egocentric and allocentric information processing and describe the brain areas involved. We recorded iEEG and analyzed broad gamma activity (50-150 Hz) in 37 epilepsy patients performing a spatial judgment task in a three-dimensional circular virtual arena. We found overlapping activation for egocentric and allocentric RFs in many brain regions, with several additional egocentric- and allocentric-selective areas. In contrast to the egocentric responses, the allocentric responses peaked later than the control ones in frontal regions with overlapping selectivity. Also, across several egocentric or allocentric selective areas, the egocentric selectivity appeared earlier than the allocentric one. We identified the maximum number of egocentric-selective channels in the medial occipito-temporal region and allocentric-selective channels around the intraparietal sulcus in the parietal cortex. Our findings favor the hypothesis that egocentric spatial coding is a more primary process, and allocentric representations may be derived from egocentric ones. They also broaden the dominant view of the dorsal and ventral streams supporting egocentric and allocentric space coding, respectively.

• Keywords
• Allocentric, Egocentric, High-frequency gamma activity, Intracranial EEG, Reference frames, Spatial judgment,
• MeSH
• Electrocorticography MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Judgment physiology   MeSH
• Spatial Processing * MeSH
• Space Perception * physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Human perception and cognition are based predominantly on visual information processing. Much of the information regarding neuronal correlates of visual processing has been derived from functional imaging studies, which have identified a variety of brain areas contributing to visual analysis, recognition, and processing of objects and scenes. However, only two of these areas, namely the parahippocampal place area (PPA) and the lateral occipital complex (LOC), were verified and further characterized by intracranial electroencephalogram (iEEG). iEEG is a unique measurement technique that samples a local neuronal population with high temporal and anatomical resolution. In the present study, we aimed to expand on previous reports and examine brain activity for selectivity of scenes and objects in the broadband high-gamma frequency range (50-150 Hz). We collected iEEG data from 27 epileptic patients while they watched a series of images, containing objects and scenes, and we identified 375 bipolar channels responding to at least one of these two categories. Using K-means clustering, we delineated their brain localization. In addition to the two areas described previously, we detected significant responses in two other scene-selective areas, not yet reported by any electrophysiological studies; namely the occipital place area (OPA) and the retrosplenial complex. Moreover, using iEEG we revealed a much broader network underlying visual processing than that described to date, using specialized functional imaging experimental designs. Here, we report the selective brain areas for scene processing include the posterior collateral sulcus and the anterior temporal region, which were already shown to be related to scene novelty and landmark naming. The object-selective responses appeared in the parietal, frontal, and temporal regions connected with tool use and object recognition. The temporal analyses specified the time course of the category selectivity through the dorsal and ventral visual streams. The receiver operating characteristic analyses identified the PPA and the fusiform portion of the LOC as being the most selective for scenes and objects, respectively. Our findings represent a valuable overview of visual processing selectivity for scenes and objects based on iEEG analyses and thus, contribute to a better understanding of visual processing in the human brain.

• Keywords
• high-frequency gamma activity, human brain, lateral occipital complex, objects, parahippocampal place area, scenes, stereoencephalography, visual processing,
• Publication type
• Journal Article MeSH