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Unilateral spatial neglect (USN) was originally regarded as a parietal syndrome, but it has become evident that USN is a disturbance in the widespread attention network. Here, we focused on an interaction between spatial neglect and non-spatial aspect of attention deficit, and aimed to establish a novel evaluation approach based on the characteristics of the spatial distribution of reaction times. We tested 174 patients with right hemisphere damage and divided them based on their prescreening scores on the Behavioral Inattention Test (BIT): (1) USN++ (n = 79: BIT131), (2) USN+ (n = 47: BIT≥131 with history of USN), and (3) RHD (n = 48: without neglect symptom). The patients were asked to conduct a touch panel-based pointing task toward 2D-arranged (seven columns × five rows) circular targets on a PC monitor, and the reaction time to each object was recorded. To evaluate aspects of attention deficit and neglect symptoms, we calculated the total average of the reaction time for all objects (RT

The subcortical visual pathway including the superior colliculus (SC), pulvinar, and amygdala has been implicated in unconscious visual processing of faces, eyes, and gaze direction in blindsight. Our previous studies reported that monkey SC and pulvinar neurons responded preferentially to images of faces while performing a delayed non-matching to sample (DNMS) task to discriminate different visual stimuli (Nguyen et al., 2013, 2014). However, the contribution of SC and pulvinar neurons to the discrimination of the facial images and subsequent behavioral performance remains unknown. Since gamma oscillations have been implicated in sensory and cognitive processes as well as behavioral execution, we hypothesized that gamma oscillations during neuronal responses might contribute to achieving the appropriate behavioral performance (i.e., a correct response). In the present study, we re-analyzed those neuronal responses in the monkey SC and pulvinar to investigate possible relationships between gamma oscillations in these neurons and behavioral performance (correct response ratios) during the DNMS task. Gamma oscillations of SC and pulvinar neuronal activity were analyzed in three phases around the stimulus onset [inter-trial interval (ITI): 1000ms before trial onset; Early: 0-200ms after stimulus onset; and Late: 300-500ms after stimulus onset]. We found that human facial images elicited stronger gamma oscillations in the early phase than the ITI and late phase in both the SC and pulvinar neurons. Furthermore, there was a significant correlation between strengths of gamma oscillations in the early phase and behavioral performance in both the SC and pulvinar. The results suggest that gamma oscillatory activity in the SC and pulvinar contributes to successful behavioral performance during unconscious perceptual and behavioral processes.

Sensorimotor incongruence (SMI) is associated with pathological pain, such as phantom limb pain. Additionally, patients with pathological pain and brain dysfunction typically present with movement disorders, including diminished voluntary control and increased variability in bimanual movement performance. In healthy subjects, SMI leads to dysesthesia and bimanual movement motor dysfunction. However, the brain localization of this activity remains unclear, particularly in SMI-induced dysesthesia and decrease in movement accuracy. In this study, 17 healthy participants were asked to perform repetitive flexion/extension exercises with their wrists in a congruent/incongruent position while viewing the activity in a mirror. Indeed, SMI induced dysesthesia and decreased bimanual movement accuracy. Moreover, beta band activities of the bilateral presupplementary (P 0.01) and bilateral cingulate (P 0.05) motor areas were decreased. Collectively, our findings indicate that SMI induces dysesthesia and movement disorders and reduces beta band activities in motor-related areas.

Eye tracking is an effective tool for identifying behavioural aspects of unilateral spatial neglect (USN), which is a common neurological syndrome that develops after a right hemisphere lesion. Here, we attempted to elucidate how the neglect symptom affects the symmetry of the gaze pattern, by performing an analysis of gaze distribution during the free viewing of a pair of horizontally flipped images. Based on their Behavioural Inattention Test (BIT) scores, 41 patients with right-hemisphere damage were classified into those with USN (n = 27) and those without USN (right hemisphere damaged - RHD; n = 14). Eye movement was recorded while the patients viewed six pairs of horizontally flipped images on a computer display. A pair of flipped images has both similar and consistent elements, as well as a reversed spatial location of objects (right-left). We calculated the gaze distribution, extent of gaze shift, total gaze distance, and gaze velocity in each direction. Our results demonstrated a significantly larger rightward gaze shift in the USN group, which showed a significant correlation with the BIT score. More importantly, the extent of gaze shift and total gaze distance were similarly modulated by the contents of the displayed images in both the USN and RHD groups. Our findings suggest that analyses of gaze distribution during the free viewing of a pair of horizontally flipped images have the potential to precisely reveal neglect behaviour, and our results provide important implications for rehabilitation.

Summary Visuospatial neglect (VSN) is a neurological syndrome of higher brain functions in which an individual fails to detect stimuli on a space that is contralateral to a hemispheric lesion. We performed a comprehensive multivariate analysis based on the principal component analysis (PCA) and cluster analysis in patients with right hemisphere stroke and then performed a determination of different elements of VSN. PCA-based cluster analysis detected distinct aspects of VSN as follows: cluster 1: low arousal and attention state, cluster 2: exogenous neglect, cluster 3: spatial working memory (SWM) deficit. Lesion analysis revealed neural correlates for each cluster and highlighted “disturbance of the ventral attention network” for the stagnation of exogenous attention and “parietal damage” for SWM deficit. Our results reveal a pathological structure of VSN as multiple components of an attention network deficit, and they contribute to the understanding of the mechanisms underlying VSN., Graphical abstract, Highlights • This study attempted to establish the pathological structure of visuospatial neglect • PCA revealed four distinct fundamental components underlying visuospatial neglect • GMM-based clustering detected six subtypes of visuospatial attention network deficit, Medical Imaging; Behavioral Neuroscience; Systems Neuroscience; Computer Modeling

The novel object recognition (NOR) test has been widely used to test memory function. We developed a 3D computerized video analysis system that estimates nose contact with an object in Long Evans rats to analyze object exploration during NOR tests. The results indicate that the 3D system reproducibly and accurately scores the NOR test. Furthermore, the 3D system captures a 3D trajectory of the nose during object exploration, enabling detailed analyses of spatiotemporal patterns of object exploration. The 3D trajectory analysis revealed a specific pattern of object exploration in the sample phase of the NOR test: normal rats first explored the lower parts of objects and then gradually explored the upper parts. A systematic injection of MK-801 suppressed changes in these exploration patterns. The results, along with those of previous studies, suggest that the changes in the exploration patterns reflect neophobia to a novel object and/or changes from spatial learning to object learning. These results demonstrate that the 3D tracking system is useful not only for detailed scoring of animal behaviors but also for investigation of characteristic spatiotemporal patterns of object exploration. The system has the potential to facilitate future investigation of neural mechanisms underlying object exploration that result from dynamic and complex brain activity.

Cerebral deposition of amyloid β protein (Aβ) is an invariant feature of Alzheimer disease (AD), and epidemiological evidence suggests that moderate consumption of foods enriched with phenolic compounds reduce the incidence of AD. We reported previously that the phenolic compounds myricetin (Myr) and rosmarinic acid (RA) inhibited Aβ aggregation in vitro and in vivo. To elucidate a mechanistic basis for these results, we analyzed the effects of five phenolic compounds in the Aβ aggregation process and in oligomer-induced synaptic toxicities.Wenow report that the phenolic compounds blocked Aβ oligomerization, and Myr promoted significantNMRchemical shift changes of monomeric Aβ. Both Myr and RA reduced cellular toxicity and synaptic dysfunction of the Aβ oligomers. These results suggest that Myr and RA may play key roles in blocking the toxicity and early assembly processes associated with Aβ through different binding. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.