Resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy

BACKGROUND Neurosurgical treatment of severe bilateral occipital lobe epilepsy usually involves two operations several mos apart.AIM To evaluate surgical resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy.METHODS This retrospective case series included patients with drug-refractory bilateral occipital lobe epilepsy treated surgically between March 2006 and November 2015.RESULTS Preoperative evaluation included scalp video-electroencephalography(EEG),magnetic resonance imaging,and PET-CT.During surgery(bilateral occipital craniotomy),epileptic foci and important functional areas were identified by EEG(intracranial cortical electrodes)and cortical functional mapping,respectively.Patients were followed up for at least 5 years to evaluate treatment outcome(Engel grade)and visual function.The 20 patients(12 males)were aged 4-30 years(median age,12 years).Time since onset was 3-20 years(median,8 years),and episode frequency was 4-270/mo(median,15/mo).Common manifestations were elementary visual hallucinations(65.0%),flashing lights(30.0%),blurred vision(20.0%)and visual field defects(20.0%).Most patients were free of disabling seizures(Engel grade I)postoperatively(18/20,90.0%)and at 1 year(18/20,90.0%),3 years(17/20,85.0%)and≥5 years(17/20,85.0%).No patients were classified Engel grade IV(no worthwhile improvement).After surgery,there was no change in visual function in 13/20(65.0%),development of a new visual field defect in 3/20(15.0%),and worsening of a preexisting defect in 4/20(20.0%).CONCLUSION Resection of bilateral occipital lobe lesions during a single operation may be applicable in bilateral occipital lobe epilepsy.

Why psychosis is frequently associated with Parkinson's disease?

Psychosis is a common non-motor symptom of Parkinson’s disease whose pathogenesis remains poorly understood. Parkinson’s disease in conjunction with psychosis has been shown to induce injury to extracorticospinal tracts as wel as within some cortical areas. In this study, Parkinson’s disease patients with psychosis who did not receive antipsychotic treatment and those without psychosis underwent diffusion tensor imaging. Results revealed that in Parkinson’s disease patients with psychosis, damage to the left frontal lobe, bilateral occipital lobe, left cingulated gyrus, and left hippocampal white-matter fibers were greater than damage to the substantia nigra or the globus pal idus. Damage to white-matter fibers in the right frontal lobe and right cingulate gyrus were also more severe than in the globus pal idus, but not the substantia nigra. Damage to frontal lobe and cingulate gyrus white-matter fibers was more apparent than that to occipital or hippocampal fiber damage. Compared with Parkinson’s disease patients without psychosis, those with psychosis had significantly lower fractional anisotropy ratios of left frontal lobe, bilateral occipital lobe, left cingu-lated gyrus, and left hippocampus to ipsilateral substantia nigra or globus pal idus, indicating more severe damage to white-matter fibers. These results suggest that psychosis associated with Par-kinson’s disease is probably associated with an imbalance in the ratio of white-matter fibers be-tween brain regions associated with psychiatric symptoms （frontal lobe, occipital lobe, cingulate gyrus, and hippocampus） and those associated with the motor symptoms of Parkinson’s disease （the substantia nigra and globus pal idus）. The relatively greater damage to white-matter fibers in psychiatric symptom-related brain regions than in extracorticospinal tracts might explain why psy-chosis often occurs in Parkinson’s disease patients.

Brain structure in post-traumatic stress disorder A voxel-based morphometry analysis

This study compared the difference in brain structure in 12 mine disaster survivors with chronic post-traumatic stress disorder, 7 cases of improved post-traumatic stress disorder symptoms, and 14 controls who experienced the same mine disaster but did not suffer post-traumatic stress disorder, using the voxel-based morphometry method. The correlation between differences in brain structure and post-traumatic stress disorder symptoms was also investigated. Results showed that the gray matter volume was the highest in the trauma control group, followed by the symptoms-improved group, and the lowest in the chronic post-traumatic stress disorder group. Compared with the symptoms-improved group, the gray matter volume in the lingual gyrus of the right occipital lobe was reduced in the chronic post-traumatic stress disorder group. Compared with the trauma control group, the gray matter volume in the right middle occipital gyrus and left middle frontal gyrus was reduced in the symptoms-improved group. Compared with the trauma control group, the gray matter volume in the left superior parietal lo- bule and right superior frontal gyrus was reduced in the chronic post-traumatic stress disorder group. The gray matter volume in the left superior parietal Iobule was significantly positively correlated with the State-Trait Anxiety Inventory subscale score in the symptoms-improved group and chronic post-traumatic stress disorder group （r = 0.477, P = 0.039）. Our findings indicate that （1） chronic post-traumatic stress disorder patients have gray matter structural damage in the prefrontal lobe, oc- cipital lobe, and parietal lobe, （2） after post-traumatic stress, the disorder symptoms are improved and gray matter structural damage is reduced, but cannot recover to the trauma-control level, and （3） the superior parietal Iobule is possibly associated with chronic post-traumatic stress disorder. Post-traumatic stress disorder patients exhibit gray matter abnormalities.

Investigating Neural Representation of Finger-Movement Directions Using Electroencephalography Independent Components

There are few EEG studies on finger movement directions because ocular artifacts also convey directional information, which makes it hard to separate the contribution of EEG from that of the ocular artifacts. To overcome this issue, we designed an experiment in which EEG’s temporal dynamics and spatial information are evaluated together to improve the performance of brain-computer interface (BCI) for classifying finger movement directions. Six volunteers participated in the study. We examined their EEG using decoding analyses. Independent components (ICs) that represented brain-source signals successfully classified the directions of the finger movements with higher rates than chance level. The weight analyses of the classifiers revealed that maximal performance of the classification was recorded at the latencies prior to the onset of finger movements. The weight analyses also revealed the relevant cortical areas including the right lingual, left posterior cingulate, left inferior temporal gyrus, and right precuneus, which indicated the involvement of the visuospatial processing. We concluded that combining spatial distribution and temporal dynamics of the scalp EEG may improve BCI performance.

A Comprehensive Overview of the Role of Visual Cortex Malfunction in Depressive Disorders: Opportunities and Challenges

Major depressive disorder(MDD)is a highly heterogeneous mental disorder,and its complex etiology and unclear mechanism are great obstacles to the diagnosis and treatment of the disease.Studies have shown that abnormal functions of the visual cortex have been reported in MDD patients,and the actions of several antidepressants coincide with improvements in the structure and synaptic functions of the visual cortex.In this review,we critically evaluate current evidence showing the involvement of the malfunctioning visual cortex in the pathophysiology and therapeutic process of depression.In addition,we discuss the molecular mechanisms of visual cortex dysfunction that may underlie the pathogenesis of MDD.Although the precise roles of visual cortex abnormalities in MDD remain uncertain,this undervalued brain region may become a novel area for the treatment of depressed patients.