[Simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions].

A 76-year-old male patient was admitted to our hospital for the treatment of acute cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions. Although his overall cognitive function was almost normal, he exhibited reduced visual sensitivity in the homonymous lower left quadrant of the visual field, left unilateral spatial neglect (USN), and simultanagnosia. Left USN improved 4 months after the onset of infarction; however, simultanagnosia persisted. To the best of our knowledge, this is the first case of simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions.

Music-based interventions for unilateral spatial neglect: A systematic review.

This study aimed to evaluate the effects of music-based interventions on unilateral spatial neglect. Five databases were retrieved prior to May 5, 2022. A range of study designs were considered, including randomized controlled trials, controlled clinical trials, cohorts, and case series/reports. Types of music-based interventions were not limited. Methodological quality of randomized trials were evaluated using the RoB 2 tool, and the RoBiNT scale was utilized to assess the quality of case studies. Two authors independently summarized main results for assessments. Search strategies identified 186 potentially relevant articles, and 10 articles were collected for in-depth analysis. Preliminary results showed that USN patients performed better in cancellation tests than bisection tests after music-based intervention. In summary, pleasant music listening may have a beneficial effect on the visual attention of USN patients, and it can be hypothesized that this is related to the positive mood and emotions of patients induced by music. Music with a dynamic auditory stimulus as a new music listening programme in USN rehabilitation is worthy of further investigation. Instrument playing intervention can be considered as a multisensory stimulation to ameliorate neglect performance via multiple mechanisms. However, current results only support the short-term positive effects of music-based interventions on USN.

Rehabilitation of hemispatial neglect in stroke.

Hemi-spatial neglect (HSN) is a debilitating post stroke cognitive deficit resulting in reduced attention to stimuli presented in the contra-lateral hemi-visual field. It adversely impacts patient's medical recovery, activities of daily living and quality of life. Early referral to Rehabilitation Medicine specialist for thorough evaluation, prompt recognition of functional impairments and formulation of a comprehensive rehabilitation plan unique to patient is important. It is part of the comprehensive and holistic management of stroke patients with HSN. We summarize the current management strategies used for post-stroke HSN rehabilitation with the options including non-invasive brain stimulation, visuomotor feedback training, robotic rehabilitation and trans-dermal nicotine patch.

Real-time fMRI and EEG neurofeedback: A perspective on applications for the rehabilitation of spatial neglect.

Spatial neglect is a neuropsychological syndrome characterized by a failure to orient, perceive, and act toward the contralesional side of the space after brain injury. Neglect is one of the most frequent and disabling neuropsychological syndromes following right-hemisphere damage, often persisting in the chronic phase and responsible for a poor functional outcome at hospital discharge. Different rehabilitation approaches have been proposed over the past 60 years, with a variable degree of effectiveness. In this point-of-view article, we describe a new rehabilitation technique for spatial neglect that directly targets brain activity and pathological physiological processes: namely, neurofeedback (NFB) with real-time brain imaging methodologies. In recent proof-of-principle studies, we have demonstrated the potential of this rehabilitation technique. Using real-time functional MRI (rt-fMRI) NFB in chronic neglect, we demonstrated that patients are able to upregulate their right visual cortex activity, a response that is otherwise reduced due to losses in top-down attentional signals. Using real-time electroencephalography NFB in patients with acute or chronic condition, we showed successful regulation with partial restoration of brain rhythm dynamics over the damaged hemisphere. Both approaches were followed by mild, but encouraging, improvement in neglect symptoms. NFB techniques, by training endogenous top-down modulation of attentional control on sensory processing, might induce sustained changes at both the neural and behavioral levels, while being non-invasive and safe. However, more properly powered clinical studies with control groups and longer follow-up are needed to fully establish the effectiveness of the techniques, identify the most suitable candidates, and determine how the techniques can be optimized or combined in the context of rehabilitation.

Neglect syndrome in post-stroke conditions: assessment and treatment (scoping review).

There is no consensus about the definition or most effective treatment for neglect syndrome. The aim of this review was therefore to evaluate the results of trials that investigated different treatment methods for neglect syndrome. A systematic literature search in PubMed and Web of Science databases was performed to identify studies that investigated the effects of neglect therapies. Authors followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Studies were selected by two assayers, and disagreement was resolved by a third reviewer. The literature search identified 202 articles: 19 met the inclusion criteria and were included for data extraction. Thirty-five different kinds of assessments were used in these studies, and 17 treatment methods were applied. Successful treatments were reported at least in some parts of the assessments in 12 studies: mirror therapy (in two trials), transcranial magnetic stimulation, street crossing test in virtual reality, smooth pursuit eye movement training, saccadic eye movement therapy, direct current stimulation, eye patching therapy, prism adaptation treatment, socially assistive pet-type therapeutic robot (PARO), Kinesiological Instrument for Normal and Altered Reaching Movement robotic device therapy, transcutaneous electrical nerve stimulation, and optokinetic stimulation (the last two methods in the same trial). No success was shown in seven trials, which contained not only single treatments but combined ones also. Authors concluded that there are no convincing results for or against any of the different therapies used for neglect syndrome. The quality of the trials is questionable, and the numbers of included patients are small in the trials.

Modifying the Adult Rat Tonotopic Map with Sound Exposure Produces Frequency Discrimination Deficits That Are Recovered with Training.

Frequency discrimination learning is often accompanied by an expansion of the functional region corresponding to the target frequency within the auditory cortex. Although the perceptual significance of this plastic functional reorganization remains debated, greater cortical representation is generally thought to improve perception for a stimulus. Recently, the ability to expand functional representations through passive sound experience has been demonstrated in adult rats, suggesting that it may be possible to design passive sound exposures to enhance specific perceptual abilities in adulthood. To test this hypothesis, we exposed adult female Long-Evans rats to 2 weeks of moderate-intensity broadband white noise followed by 1 week of 7 kHz tone pips, a paradigm that results in the functional over-representation of 7 kHz within the adult tonotopic map. We then tested the ability of exposed rats to identify 7 kHz among distractor tones on an adaptive tone discrimination task. Contrary to our expectations, we found that map expansion impaired frequency discrimination and delayed perceptual learning. Rats exposed to noise followed by 15 kHz tone pips were not impaired at the same task. Exposed rats also exhibited changes in auditory cortical responses consistent with reduced discriminability of the exposure tone. Encouragingly, these deficits were completely recovered with training. Our results provide strong evidence that map expansion alone does not imply improved perception. Rather, plastic changes in frequency representation induced by bottom-up processes can worsen perceptual faculties, but because of the very nature of plasticity these changes are inherently reversible.SIGNIFICANCE STATEMENT The potent ability of our acoustic environment to shape cortical sensory representations throughout life has led to a growing interest in harnessing both passive sound experience and operant perceptual learning to enhance mature cortical function. We use sound exposure to induce targeted expansions in the adult rat tonotopic map and find that these bottom-up changes unexpectedly impair performance on an adaptive tone discrimination task. Encouragingly, however, we also show that training promotes the recovery of electrophysiological measures of reduced neural discriminability following sound exposure. These results provide support for future neuroplasticity-based treatments that take into account both the sensory statistics of our external environment and perceptual training strategies to improve learning and memory in the adult auditory system.

Association between prism adaptation and auditory cues on spatial navigation in individuals with unilateral neglect.

BACKGROUND: Unilateral neglect is common among right-hemispheric stroke individuals and also concerns the auditory modality. Prism adaptation can improve auditory extinction during a dichotic listening task, but its effect during an ecological task has not been studied. OBJECTIVE: The main objective was to evaluate whether lateralized cueing before and after prism adaptation improved virtual spatial navigation of stroke individuals with visual and auditory unilateral neglect. Secondary objectives were to assess spatial memory and obtain a better understanding of the mechanism of the cueing treatment by using an eye-tracker. METHODS: We included 22 stroke individuals with left visual and auditory neglect, 14 individuals without neglect, and 12 healthy controls. After a familiarization task, participants underwent 3 evaluation sessions. Participants were first passively shown a path that they had then to actively reproduce by using a joystick. A path with lateralized beeping sounds indicating direction and a path without any sounds were followed in a randomized order. After prism adaptation, the participants followed a third path with lateralized beeping sounds. The time of navigation and number of trajectory mistakes were recorded. After navigation, spatial memory was assessed. Additionally, an eye-tracker was used during the navigation period. RESULTS: The navigational performance of participants with neglect was significantly better with than without auditory cues, especially after prism adaptation. With auditory cues, participants without neglect reached the navigational performance of healthy controls. The spatial memory of individuals with neglect was significantly lower with auditory cues. Eye-tracking analyses showed that participants with neglect made more saccades and looked longer at the right-square angles in the absence of auditory cues. CONCLUSIONS: This study demonstrates the positive effect of auditory cues in virtual spatial navigation of individuals with visual and auditory neglect and the potentiation of the help of cues after prism adaptation.

Differential Patterns of Visual Sensory Alteration Underlying Face Emotion Recognition Impairment and Motion Perception Deficits in Schizophrenia and Autism Spectrum Disorder.

BACKGROUND: Impaired face emotion recognition (FER) and abnormal motion processing are core features in schizophrenia (SZ) and autism spectrum disorder (ASD) that have been linked to atypical activity within the visual cortex. Despite overlaps, only a few studies have directly explored convergent versus divergent neural mechanisms of altered visual processing in ASD and SZ. We employed a multimodal imaging approach to evaluate FER and motion perception in relation to functioning of subcortical and cortical visual regions. METHODS: Subjects were 20 high-functioning adults with ASD, 19 patients with SZ, and 17 control participants. Behavioral measures of coherent motion sensitivity and FER along with electrophysiological and functional magnetic resonance imaging measures of visual pattern and motion processing were obtained. Resting-state functional magnetic resonance imaging was used to assess the relationship between corticocortical and thalamocortical connectivity and atypical visual processing. RESULTS: SZ and ASD participants had intercorrelated deficits in FER and motion sensitivity. In both groups, reduced motion sensitivity was associated with reduced functional magnetic resonance imaging activation in the occipitotemporal cortex and lower delta-band electroencephalogram power. In ASD, FER deficits correlated with hyperactivation of dorsal stream regions and increased evoked theta power. Activation of the pulvinar correlated with abnormal alpha-band modulation in SZ and ASD with under- and overmodulation, respectively, predicting increased clinical symptoms in both groups. CONCLUSIONS: SZ and ASD participants showed equivalent deficits in FER and motion sensitivity but markedly different profiles of physiological dysfunction. The specific pattern of deficits observed in each group may help guide development of treatments designed to downregulate versus upregulate visual processing within the respective clinical groups.

Dissociable Contributions of Precuneus and Cerebellum to Subjective and Objective Neuropathy in HIV.

Neuropathy, typically diagnosed by the presence of either symptoms or signs of peripheral nerve dysfunction, remains a frequently reported complication in the antiretroviral (ART)-treated HIV population. This study was conducted in 109 healthy controls and 57 HIV-infected individuals to investigate CNS regions associated with neuropathy. An index of objective neuropathy was computed based on 4 measures: deep tendon ankle reflex, vibration sense (great toes), position sense (great toes), and 2-point discrimination (feet). Subjective neuropathy (self-report of pain, aching, or burning; pins and needles; or numbness in legs or feet) was also evaluated. Structural MRI data were available for 126/166 cases. The HIV relative to the healthy control group was impaired on all 4 signs of neuropathy. Within the HIV group, an objective neuropathy index of 1 (bilateral impairment on 1 measure) or 2 (bilateral impairment on at least 2/4 measures) was associated with older age and a smaller volume of the cerebellar vermis. Moderate to severe symptoms of neuropathy were associated with more depressive symptoms, reduced quality of life, and a smaller volume of the parietal precuneus. This study is consistent with the recent contention that ART-treated HIV-related neuropathy has a CNS component. Distinguishing subjective symptoms from objective signs of neuropathy allowed for a dissociation between the precuneus, a brain region involved in conscious information processing and the vermis, involved in fine tuning of limb movements. Graphical Abstract In HIV patients, objective signs of neuropathy correlated with smaller cerebellar vermis (red) volumes whereas subjective symptoms of neuropathy were associated with smaller precuneus (blue) volumes.

Using real-time fMRI neurofeedback to restore right occipital cortex activity in patients with left visuo-spatial neglect: proof-of-principle and preliminary results.

Hemineglect is common after right parietal stroke, characterised by impaired awareness for stimuli in left visual space, with suppressed neural activity in the right visual cortex due to losses in top-down attention signals. Here we sought to assess whether hemineglect patients are able to up-regulate their right visual cortex activity using auditory real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback. We also examined any effect of this training procedure on neglect severity. Two different neurofeedback methods were used. A first group of six patients was trained to up-regulate their right visual cortex activity and a second group of three patients was trained to control interhemispheric balance between their right and left visual cortices. Over three sessions, we found that the first group successfully learned to control visual cortex activity and showed mild reduction in neglect severity, whereas the second group failed to control the feedback and showed no benefit. Whole brain analysis further indicated that successful up-regulation was associated with a recruitment of bilateral fronto-parietal areas. These findings provide a proof of concept that rt-fMRI neurofeedback may offer a new approach to the rehabilitation of hemineglect symptoms, but further studies are needed to identify effective regulation protocols and determine any reliable impact on clinical symptoms.

Absence of associative motor learning and impaired time perception in a rare case of complete cerebellar agenesis.

Primary cerebellar agenesis (PCA), a brain disease where the cerebellum does not develop, is an extremely rare congenital disease with only eleven living cases reported thus far. Studies of the PCA case will thus provide valuable insights into the necessity of cerebellar development for controlling and modulating cognitive functions of the brain. In this follow-up study, we further investigated the performance of associative learning and time perception of a 26-year-old female complete PCA case. We assessed whether delayed eyeblink conditioning (EBC), which represents prototypical associative motor learning function of the cerebellum, could be partially compensated by the extracerebellar brain regions in complete absence of the cerebellum. We also assessed whether the cerebellum, a critical brain region for millisecond-range interval timing, is essential for perception of the second-range time interval. Twelve neurotypical age-matched individuals were used as controls. We found that although the complete PCA patient had only mild to moderate motor deficits, she was unable to perform the delayed EBC even after 1-week of extensive training. Additionally, the PCA patient also performed poorly during time reproduction experiments in which she overproduced the millisecond-range time intervals, while underproduced the second-range time intervals. The PCA patient also failed to perform the temporal eyeblink conditioning with a 5 s fixed interval as the conditioned stimulus. These results indicate that the cerebellum is indispensable for associative motor learning and involved in timing of sub-second intervals, as well as in the perception of second-range intervals.

Thalamic Lesions and Aphasia or Neglect.

PURPOSE OF REVIEW: When the thalamus is damaged, not only are there neurological symptoms such as sensory impairment, hemianopia, or motor control disorders, but there are also various neuropsychological symptoms. We discuss the basic anatomy and function of the thalamus followed by a discussion of thalamic aphasia and hemineglect. RECENT FINDINGS: Subcortical lesions in patients with hemineglect involved the anatomical network directly linked to the superior temporal gyrus. Furthermore, the pulvinar, part of the thalamus, may be associated with hemineglect. General linguistic tasks activated the thalami, depending on the difficulty, as well as the frontal and temporal lobes. The thalamus may play a role in language and be involved in the activation of cortical language areas, and in the linguistic integration function via verbal memory and semantic mechanisms. Thalamic lesions are associated with aphasia and hemineglect. It is possible the mechanisms and such neuropsychological may be different depending on the size and site of the thalamic lesion.

The way to "left" Piazza del Popolo: damage to white matter tracts in representational neglect for places.

The ability of seeing with the mind's eye, the visual mental imagery, is peculiarly compromised in patients with representational neglect. Representational neglect affects the processing of the left side of a mental image and may selectively concern the ability to imagine places and/or objects. Right-brain damaged patients with representational neglect for places (RN+) lose the ability to imagine themselves within a familiar place and fail in transforming an egocentric representation of the environment into an allocentric one and vice-versa. A peak region located at the posterior junction between the parietal and temporal lobes has emerged as pivotal in determining representational neglect for places. Here we aimed at verifying whether white matter disconnections affecting parietal lobe, by preventing the integration of egocentric information with the allocentric one, play a role in representational neglect for places. A track-wise statistical analysis on 58 right brain damaged patients, with and without extrapersonal perceptual neglect and/or representational neglect for places, suggests that the disconnection of the superior longitudinal fasciculus and that of the posterior arcuate segment, together with the disconnection of a fronto-parietal u-shaped tract, may be crucial in determining the representational neglect for places. These results suggest that representational neglect for places emerges from a complex pattern of lesion location and disconnection that involves parietal, temporal and frontal lobes.

Cotard Syndrome.

Cotard's syndrome is often described as the delusional belief that one is dead or non-existent. However, Jules Cotard's initial description (1880) of the "delusion of negations" was much richer and also involved delusions and claims of immortality and enormity, feelings of damnation, and illusions of bodily dissolution and transformation. Alternatively conceived as an extreme case of depression, hypochondria, or psychosis, the condition is considered rare and remains poorly understood. Cotard himself provided a taxonomy and several explanations for the condition, focusing on its distinction from classical persecutory delusions and suggesting that it could be a kind of reversed grandiosity. He proposed a psychosensory basis in the dissolution of mental imagery, which he then extended to a more general psychomotor impairment of volition. Other early authors highlighted a disorder of the bodily self, and more recent theories postulated an impairment of right hemispheric functions, leading to perceptual and somatosensory feelings of unreality, which coupled with reasoning impairments and an internalized attributional style led in turn to beliefs of non-existence. However, despite its striking presentation and its relevance to our understanding of self-awareness, Cotard's syndrome remains an elusive condition, rarely reported and poorly researched.

Paediatric otitis media with effusion is connected to deficits in music perception.

PURPOSE: This study tested the hypothesis that children with otitis media with effusion (OME) attending a primary school are at risk of impairment of their musical skills. OME is characterized as an inflammation with accumulation of secretion in the tympanic cavity, leading to conductive hearing loss. METHOD: Perception of music in children is assessed using the Montreal Battery of Evaluation of Music Abilities (MBEMA). Listeners are required to judge whether two successive melodies are the same or different on tests of scale, contour, interval and rhythm. They are also queried by a memory test. A total of 92 children (49 girls and 43 boys), aged 6.0-8.0 years (mean 7.3, SD 0.7), attending a music school, were examined using the MBEMA. Twenty-three children were allocated to the OME group, while the remaining 69 to the control group. Age and gender distribution did not differ between children with OME and the controls. All participants had normal bone conduction hearing thresholds. The conductive hearing loss of the children with OME did not exceed 40 dB at any frequency. Their OME was bilateral and had lasted 3-9 months. RESULTS: The obtained scale, rhythm and total MBEMA scores were higher in the control group than in the OME group, with statistically significant differences for scale and rhythm scores. CONCLUSIONS: OME can influence music perception in children at the beginning of their school education. OME correlates with both pitch- and rhythm-related aspects of music perception.

For Better or Worse: The Effect of Prismatic Adaptation on Auditory Neglect.

Patients with auditory neglect attend less to auditory stimuli on their left and/or make systematic directional errors when indicating sound positions. Rightward prismatic adaptation (R-PA) was repeatedly shown to alleviate symptoms of visuospatial neglect and once to restore partially spatial bias in dichotic listening. It is currently unknown whether R-PA affects only this ear-related symptom or also other aspects of auditory neglect. We have investigated the effect of R-PA on left ear extinction in dichotic listening, space-related inattention assessed by diotic listening, and directional errors in auditory localization in patients with auditory neglect. The most striking effect of R-PA was the alleviation of left ear extinction in dichotic listening, which occurred in half of the patients with initial deficit. In contrast to nonresponders, their lesions spared the right dorsal attentional system and posterior temporal cortex. The beneficial effect of R-PA on an ear-related performance contrasted with detrimental effects on diotic listening and auditory localization. The former can be parsimoniously explained by the SHD-VAS model (shift in hemispheric dominance within the ventral attentional system; Clarke and Crottaz-Herbette 2016), which is based on the R-PA-induced shift of the right-dominant ventral attentional system to the left hemisphere. The negative effects in space-related tasks may be due to the complex nature of auditory space encoding at a cortical level.

Overestimation of threat from neutral faces and voices in social anxiety.

BACKGROUND AND OBJECTIVES: Social anxiety (SA) is associated with a tendency to interpret social information in a more threatening manner. Most of the research in SA has focused on unimodal exploration (mostly based on facial expressions), thus neglecting the ubiquity of cross-modality. To fill this gap, the present study sought to explore whether SA influences the interpretation of facial and vocal expressions presented separately or jointly. METHODS: Twenty-five high socially anxious (HSA) and 29 low socially anxious (LSA) participants completed a forced two-choice emotion identification task consisting of angry and neutral expressions conveyed by faces, voices or combined faces and voices. Participants had to identify the emotion (angry or neutral) of the presented cues as quickly and precisely as possible. RESULTS: Our results showed that, compared to LSA, HSA individuals show a higher propensity to misattribute anger to neutral expressions independent of cue modality and despite preserved decoding accuracy. We also found a cross-modal facilitation effect at the level of accuracy (i.e., higher accuracy in the bimodal condition compared to unimodal ones). However, such effect was not moderated by SA. LIMITATIONS: Although the HSA group showed clinical cut-off scores at the Liebowitz Social Anxiety Scale, one limitation is that we did not administer diagnostic interviews. Upcoming studies may want to test whether these results can be generalized to a clinical population. CONCLUSIONS: These findings highlight the usefulness of a cross-modal perspective to probe the specificity of biases in SA.

Cortico-thalamic disconnection in a patient with supernumerary phantom limb.

Supernumerary phantom limb (SPL) designates the experience of an illusory additional limb occurring after brain damage. Functional neuroimaging during SPL movements documented increased response in the ipsilesional supplementary motor area (SMA), premotor cortex (PMC), thalamus and caudate. This suggested that motor circuits are important for bodily related cognition, but anatomical evidence is sparse. Here, we tested this hypothesis by studying an extremely rare patient with chronic SPL, still present 3 years after a vascular stroke affecting cortical and subcortical right-hemisphere structures. Anatomical analysis included an advanced in vivo reconstruction of white matter tracts using diffusion-based spherical deconvolution. This reconstruction demonstrated a massive and relatively selective disconnection between anatomically preserved SMA/PMC and the thalamus. Our results provide strong anatomical support for the hypothesis that cortico-thalamic loops involving motor-related circuits are crucial to integrate sensorimotor processing with bodily self-awareness.