Distinct brain network structure of mesial temporal lobe epilepsy compared to that of neocortical epilepsy: functional MRI study with surgically treated patients.

Objective: Mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy (NE) have different anatomo-clinical characteristics. The authors hypothesized that this may be reflected in the different functional connectivity of the epileptogenic zone between mTLE and NE. The authors, therefore, examined preoperative resting-state functional connectivity MRI with regional global connectivity (rGC) analysis for surgically treated patients.

Regional abnormality of functional connectivity is associated with clinical manifestations in individuals with intractable focal epilepsy.

We explored regional functional connectivity alterations in intractable focal epilepsy brains using resting-state functional MRI. Distributions of the network parameters (corresponding to degree and eigenvector centrality) measured at each brain region for all 25 patients were significantly different from age- and sex-matched control data that were estimated by a healthy control dataset (n = 582, 18-84 years old). The number of abnormal regions whose parameters exceeded the mean + 2 SD of age- and sex-matched data for each patient were associated with various clinical parameters such as the duration of illness and seizure severity.

Detection of gastric slow oscillatory contraction using parasagittal cine MR images: Comparison with simultaneously measured electrogastrogram.

Purpose: To determine if parasagittal gastric cine magnetic resonance imaging (MRI) is able to measure gastric oscillatory contractions around 0.05 Hz and to determine its relationship with electrical activity as measured by electrogastrography (EGG).

Methods: Assessment of the gastric motility is important for the research of the enteric nervous system and for the diagnosis of functional gastric disorders.

Increased large-scale inter-network connectivity in relation to impulsivity in Parkinson's disease.

Impulsivity is a neuropsychiatric feature of Parkinson's disease (PD). We investigated the pathophysiology of impulsivity in PD using resting-state functional magnetic resonance imaging (rs-fMRI). We investigated 45 patients with idiopathic PD and 21 healthy controls.

Effects of perinatal blood pressure on maternal brain functional connectivity.

Perinatal hypertensive disorder including pre-eclampsia is a systemic syndrome that occurs in 3-5% of pregnant women. It can result in various degrees of brain damage. A recent study suggested that even gestational hypertension without proteinuria can cause cardiovascular or cognitive impairments later in life.

Effects of gender, digit ratio, and menstrual cycle on intrinsic brain functional connectivity: A whole-brain, voxel-wise exploratory study using simultaneous local and global functional connectivity mapping.

Introduction: Gender and sex hormones influence brain function, but their effects on functional network organization within the brain are not yet understood.

Methods: We investigated the influence of gender, prenatal sex hormones (estimated by the 2D:4D digit ratio), and the menstrual cycle on the intrinsic functional network organization of the brain (as measured by 3T resting-state functional MRI (rs-fMRI)) using right-handed, age-matched university students (100 males and 100 females). The mean (±) age was 20.

Severity of Premenstrual Symptoms Predicted by Second to Fourth Digit Ratio.

Women of reproductive age often experience a variety of unpleasant symptoms prior to the onset of menstruation. While genetics may influence the variability of these symptoms and their severity among women, the exact causes remain unknown. We hypothesized that symptom variability originates from differences in the embryonic environment and thus development caused by variation in exposure to sex hormones.

Interhemispheric disconnectivity in the sensorimotor network in bipolar disorder revealed by functional connectivity and diffusion tensor imaging analysis.

Background: Little is known regarding interhemispheric functional connectivity (FC) abnormalities via the corpus callosum in subjects with bipolar disorder (BD), which might be a key pathophysiological basis of emotional processing alterations in BD.

Methods: We performed tract-based spatial statistics (TBSS) using diffusion tensor imaging (DTI) in 24 healthy control (HC) and 22 BD subjects. Next, we analyzed the neural networks with independent component analysis (ICA) in 32HC and 25 BD subjects using resting-state functional magnetic resonance imaging.

Elucidating the aberrant brain regions in bipolar disorder using T1-weighted/T2-weighted magnetic resonance ratio images.

Although diffusion tensor imaging (DTI) have revealed brain abnormalities in bipolar disorder (BD) subjects, DTI methods might not detect disease-related abnormalities in the white matter (WM) where nerve fibers are crossing. We investigated BD myelin-related abnormal brain regions in both gray matter and WM for 29 BD and 33 healthy control (HC) participants using T1-weighted (T1w)/T2-weighted (T2w) ratio images that increase myelin-related contrast irrespective of nerve fiber orientation. To check effect of the brain volume, the results were compared with those of voxel-based morphometry (VBM).

Use of T1-weighted/T2-weighted magnetic resonance ratio images to elucidate changes in the schizophrenic brain.

Introduction: One leading hypothesis suggests that schizophrenia (SZ) is a neurodevelopmental disorder caused by genetic defects in association with environmental risk factors that affect synapse and myelin formation. Recent magnetic resonance imaging (MRI) studies of SZ brain showed both gray matter (GM) reduction and white matter (WM) fractional anisotropy reduction. In this study, we used T1-weighted (T1w)/T2-weighted (T2w) MRI ratio images, which increase myelin-related signal contrast and reduce receiver-coil bias.

Alterations of Regional Cerebral Blood Flow in Tinnitus Patients as Assessed Using Single-Photon Emission Computed Tomography.

Tinnitus is the perception of phantom sound without an external auditory stimulus. Using neuroimaging techniques, such as positron emission tomography, electroencephalography, magnetoencephalography, and functional magnetic resonance imaging (fMRI), many studies have demonstrated that abnormal functions of the central nervous system are closely associated with tinnitus. In our previous research, we reported using resting-state fMRI that several brain regions, including the rectus gyrus, cingulate gyrus, thalamus, hippocampus, caudate, inferior temporal gyrus, cerebellar hemisphere, and medial superior frontal gyrus, were associated with tinnitus distress and loudness.

Dopamine regulates distinctively the activity patterns of striatal output neurons in advanced parkinsonian primates.

Nigrostriatal dopamine denervation plays a major role in basal ganglia circuitry disarray and motor abnormalities of Parkinson's disease (PD). Studies in rodent and primate models have revealed that striatal projection neurons, namely, medium spiny neurons (MSNs), increase the firing frequency. However, their activity pattern changes and the effects of dopaminergic stimulation in such conditions are unknown.

Contrast enrichment of spinal cord MR imaging using a ratio of T1-weighted and T2-weighted signals.

Purpose: We aimed to assess if the T1-weighted (T1w)/T2-weighted (T2w) signal ratio could be used to improve image contrast in MR spinal cord imaging.

Materials And Methods: T1w and T2w cervical spinal cord MR images were acquired from 23 normal subjects using 3 Tesla (T) MR scanner. In addition, a multiple sclerosis patient, and a cervical spondylotic myelopathy patient were evaluated.

Brain regions responsible for tinnitus distress and loudness: a resting-state FMRI study.

Subjective tinnitus is characterized by the perception of phantom sound without an external auditory stimulus. We hypothesized that abnormal functionally connected regions in the central nervous system might underlie the pathophysiology of chronic subjective tinnitus. Statistical significance of functional connectivity (FC) strength is affected by the regional autocorrelation coefficient (AC).

Variance and autocorrelation of the spontaneous slow brain activity.

Slow (<0.1 Hz) oscillatory activity in the human brain, as measured by functional magnetic imaging, has been used to identify neural networks and their dysfunction in specific brain diseases. Its intrinsic properties may also be useful to investigate brain functions.

Auditory thalamic reticular nucleus of the rat: anatomical nodes for modulation of auditory and cross-modal sensory processing in the loop connectivity between the cortex and thalamus.

The auditory sector of the thalamic reticular nucleus (TRN) plays a pivotal role in gain and/or gate control of auditory input relayed from the thalamus to cortex. The TRN is also likely involved in cross-modal sensory processing for attentional gating function. In the present study, we anatomically examined how cortical and thalamic afferents intersect in the auditory TRN with regard to these two functional pathways.

Activation of mitogen-activated protein kinase in descending pain modulatory system.

The descending pain modulatory system is thought to undergo plastic changes following peripheral tissue injury and exerts bidirectional (facilitatory and inhibitory) influence on spinal nociceptive transmission. The mitogen-activated protein kinases (MAPKs) superfamily consists of four main members: the extracellular signal-regulated protein kinase1/2 (ERK1/2), the c-Jun N-terminal kinases (JNKs), the p38 MAPKs, and the ERK5. MAPKs not only regulate cell proliferation and survival but also play important roles in synaptic plasticity and memory formation.

Optimum stimulus size for the human brain to respond to motion: a magnetoencephalographic study.

Objective: To determine if there is an optimum spatial extent for the detection of moving objects in humans.

Methods: We investigated human brain responses to motion at various speeds (2.9-23.

Changes in regional blood flow induced by unilateral subthalamic nucleus stimulation in patients with Parkinson's disease.

Changes in regional cerebral blood flow (rCBF) induced by unilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) were investigated in 7 consecutive patients with Parkinson's disease, 4 men and 3 women (mean age 62.3 +/- 8.1 years), who underwent rCBF measurement by N-isopropyl-p-(iodine-123)-iodoamphetamine single photon emission computed tomography at rest before and after unilateral STN DBS preoperatively in the on-drug condition, and postoperatively in the on-drug and on-stimulation condition.

Human brain response to visual stimulus between lower/upper visual fields and cerebral hemispheres.

We studied the human brain response to visual stimulation in which a square area was randomly presented in upper and lower visual fields (VFs). Seven normal volunteers carried out a contrast-based visual search task. Magnetic responses were detected in the bilateral parietal regions at 200-250 ms after stimulus onset.

Intact point-light walker processing in Williams syndrome: a magnetoencephalography study.

Williams syndrome (WS) is a rare genetic disorder that results in profound spatial cognitive deficits. Several behavioral studies have showed that point-light walker (PLW) perception is intact in children and adults with WS; however, the neural responses underlying PLW perception in adults with WS have not been fully investigated. In this study,we studied an adult with WS by magnetoencephalography.

Staged bilateral deep brain stimulation of the subthalamic nucleus for the treatment of Parkinson's disease.

Background: Several investigators have described the efficacy and safety of unilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) for the treatment of Parkinson's disease (PD). Some patients who underwent unilateral STN DBS required additional surgery on the contralateral side because the unilateral treatment was insufficient. The goal of this study was to assess the efficacy and safety of staged bilateral STN DBS compared to the simultaneous bilateral procedure.

Neural responses related to point-light walker perception: a magnetoencephalographic study.

Objective: The aim of this study is to extract magnetoencephalographic responses relating to the processing of point-light walker (PLW).

Methods: To attenuate neural activities in the lower visual areas, we presented a scrambled-PLW as a first stimulus and then either an upright- or inverted-PLW/scrambled-PLW as a second stimulus. Each point of the scrambled-PLW stimulus had the same velocity vector as the points of the PLW stimulus, but points were interchanged randomly.

Temporal dynamics of adaptation to natural sounds in the human auditory cortex.

We aimed at testing the cortical representation of complex natural sounds within auditory cortex by conducting 2 human magnetoencephalography experiments. To this end, we employed an adaptation paradigm and presented subjects with pairs of complex stimuli, namely, animal vocalizations and spectrally matched noise. In Experiment 1, we presented stimulus pairs of same or different animal vocalizations and same or different noise.

Human brain activation in response to olfactory stimulation by intravenous administration of odorants.

To identify the BOLD effects related to olfaction in humans, we recorded functional magnetic resonance imaging (fMRI) scans in response intravenously instilled thiamine propyl disulfide (TPD) and thiamine tetrahydrofurfuryl disulfide monohydrochloride (TTFD). TPD and TTFD evoked a strong and weak odor sensation, respectively. Since we did not spray the odor stimuli directly, this method is expected to reduce the effect caused by direct stimulation of the trigeminal nerve.