Low blood concentration of alcohol enhances activity related to stopping failure in the right inferior frontal cortex.

This study investigated the effects of low doses of alcohol, which are acceptable for driving a car, on inhibitory control and neural processing using the stop-signal task (SST) in 17 healthy right-handed social drinkers. The study employed simultaneous functional magnetic resonance imaging and electromyography (EMG) recordings to assess behavioral and neural responses under conditions of low-dose alcohol (breath-alcohol concentration of 0.15 mg/L) and placebo. The results demonstrated that even a small amount of alcohol consumption prolonged Go reaction times in the SST and modified stopping behavior, as evidenced by a decrease in the frequency and magnitude of partial response EMG that did not result in button pressing during successful inhibitory control. Furthermore, alcohol intake enhanced neural activity during failed inhibitory responses in the right inferior frontal cortex, suggesting its potential role in behavioral adaptation following stop-signal failure. These findings suggest that even low levels of alcohol consumption within legal driving limits can greatly impact both the cognitive performance and brain activity involved in inhibiting responses. This research provides important evidence on the neurobehavioral effects of low-dose alcohol consumption, with implications for understanding the biological basis of impaired motor control and decision-making and potentially informing legal guidelines on alcohol consumption.

Modulation of alpha activity in the parieto-occipital area by distractors during a visuospatial working memory task: a magnetoencephalographic study.

Oscillatory brain activity is known to play an essential role in information processing in working memory. Recent studies have indicated that alpha activity (8-13 Hz) in the parieto-occipital area is strongly modulated in working memory tasks. However, the function of alpha activity in working memory is open to several interpretations, such that alpha activity may be a direct neural correlate of information processing in working memory or may reflect disengagement from information processing in other brain areas. To examine the functional contribution of alpha activity to visuospatial working memory, we introduced visuospatial distractors during a delay period and examined neural activity from the whole brain using magnetoencephalography. The strength of event-related alpha activity was estimated using the temporal spectral evolution (TSE) method. The results were as follows: (1) an increase of alpha activity during the delay period as indicated by elevated TSE curves was observed in parieto-occipital sensors in both the working memory task and a control task that did not require working memory; and (2) an increase of alpha activity during the delay period was not observed when distractors were presented, although TSE curves were constructed only from correct trials. These results indicate that the increase of alpha activity is not directly related to information processing in working memory but rather reflects the disengagement of attention from the visuospatial input.

Appraisal of definition of baseline length for somatosensory evoked magnetic fields.

BACKGROUND: The baseline (BL) segment in the prestimulus period is generally assigned as a reference of evoked activities. However, an experimenter empirically defines its length in each condition. So far, the criterion for the length of a BL segment has not been established. NEW METHOD: We evaluated the effect of the length of the BL segment by recording somatosensory evoked magnetic fields (SEFs) under fixed stimulus onset asynchrony (SOA). For the evaluation of the length of the BL segment in the prestimulus period, five proportions in relation to SOA were used as the BL segment. In addition, we adopted other two types of BL segment which were the single data point measured from the value of stimulus onset (BL0) and the mean value of the whole raw data throughout the recording (DC mean). We investigated the influence of the BL segments on SEFs by utilizing two indicators: normalized N20 m amplitudes and estimated locations of corresponding equivalent current dipoles (ECDs). RESULTS: Both indicators did not show any significant differences, based on the factor of BL segments, in any SOA conditions. COMPARISON WITH EXISTING METHOD: The BL0 had by far the largest variation in the ECD locations.Therefore, utilizing stimulus onset as the BL segment should be avoided. In addition, considering that other BL segments provided comparable values by the two indicators, the DC mean can reasonably be adopted. CONCLUSIONS: We suggest that utilizing the DC mean could be employed as the BL segment.

Retained absolute pitch after selective amygdalohippocampectomy.

This study assessed the pre-operative chronic condition and effect of epilepsy surgery in a 21-year-old Japanese woman with drug-resistant right temporal lobe epilepsy (TLE). For this patient, it was crucially important to preserve language and her music capabilities, including absolute pitch (AP), which is found in the general population at less than 0.1%. The patient became seizure free, and her AP capability was preserved after selective amygdalohippocampectomy in the non-dominant right hemisphere. Most of the neuropsychological test (WAIS-III and WMS-R) scores remained in the normal range, except for low scores in verbal memory and markedly improved attention/concentration index. The patient's pre- and postoperative brain function related to language and music capabilities were investigated using functional magnetic resonance imaging (fMRI) based on two language tasks and a music task (listening to melodies). While task performance was similar in pre- and postoperative examinations, her brain activation patterns markedly differed. The most striking difference was during the music task: areas with significant activation existed in the bilateral frontal and temporal lobes before surgery, whereas postoperative activation was confined to a very limited region in the left angular gyrus. The authors speculate that the surgery triggered some change in functional organization in the brain, which contributed to preserving her capabilities.

Virtual needle pain stimuli activates cortical representation of emotions in normal volunteers.

Psychological factors are known to play an extremely important role in the maintenance and development of chronic pain conditions. However, it is unclear how such factors relate to the central neural processing of nociceptive transmission in healthy individuals. To investigate this issue, the activation of the brain was studied in 30 healthy volunteers responding to virtual pain stimuli by fMRI. In the first series of the study (non-preconditioned study), 15 participants were shown a digital video demonstrating an injection needle puncturing the right palm. In the second series of the study (pre-conditioned study), same-task paradigms were used for another 15 participants. Prior to the fMRI session, real needle punctuate stimuli were applied to the right palm of participants for pre-conditioning. fMRI analysis revealed that bilateral activations in anterior insula (BA45), parietal operculum (S2: BA40), premotor area, medial globus pallidus, inferior occipital gyrus (BA18), left temporal association cortex, right fusiform gyrus, right parietal association cortex and cerebellum occurred due to the task in the preconditioned group. On the other hand, right parietal operculum (S2: BA40), premotor area, parietal association cortex, left inferior frontal gyrus and bilateral temporal association cortex were activated in the non-preconditioned group. In addition, activation of anterior insula, inferior frontal gyrus, precentral gyrus and cerebellum significantly increased in the preconditioned group compared with the non-preconditioned group. These results suggest that the virtual needle puncture task caused memory retrieval of unpleasant experiences which is possibly related to empathy for pain, resulting in the activation of specific brain areas.

Working memory deficit in drug-resistant epilepsy with an amygdala lesion.

This study compared temporal lobe epilepsy (TLE) patients with amygdala lesion (AL) without hippocampal sclerosis (HS) (TLE-AL) with patients with TLE and HS without AL (TLE-HS). Both subtypes of TLE arose from the right hemisphere. The TLE-AL group exhibited a lower Working Memory Index (WMI) on the Wechsler Adult Intelligence Scale, third edition (WAIS-III), indicating that the amygdala in the right hemisphere is involved in memory-related function. [18F]fluorodeoxyglucose positron emission topography (FDG-PET) showed glucose hypometabolism limited to the right uncus for the TLE-AL group. The results suggest the importance of considering cognitive functions in the non-dominant hemisphere to prevent impairment after surgery.

Establishing a New Screening System for Mild Cognitive Impairment and Alzheimer's Disease with Mental Rotation Tasks that Evaluate Visuospatial Function.

BACKGROUND: The mental rotation task is well-known for the assessment of visuospatial function; however, it has not been used for screening of dementia patients. OBJECTIVE: The aim of this study was to create a simple screening test for patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) by focusing on non-amnestic symptoms. METHODS: Age-matched healthy controls (age 75.3±6.8), patients with MCI (76.5±5.5), and AD (78.2±5.0) participated in this study. They carried out mental rotation tasks targeting geometric graphics or alphabetical characters with three rotating angles (0°, 90°, and 180°) and indicated the correct answer. Response accuracy and reaction time were recorded along with their eye movements using an eye tracker. To quantify their visual processing strategy, the run count ratio (RC ratio) was calculated by dividing the mean number of fixations in incorrect answers by that in correct answers. RESULTS: AD patients showed lower accuracy and longer reaction time than controls. They also showed a significantly greater number of fixation and smaller saccade amplitude than controls, while fixation duration did not differ significantly. The RC ratio was higher for AD, followed by MCI and control groups. By setting the cut-off value to 0.47 in the 180° rotating angle task, we could differentiate MCI patients from controls with a probability of 80.0%. CONCLUSIONS: We established a new screening system for dementia patients by evaluating visuospatial function. The RC ratio during a mental rotation task is useful for discriminating MCI patients from controls.

Heterospecific and conspecific social cognition in the anterior cingulate cortex.

The development of human social cognition has allowed interactions with other species and the formation of a cooperative multi-species society. This feature posited keen attention on the following question: is heterospecific social cognition represented in the same brain areas as conspecific social cognition? Here we investigated brain activity accompanying the facial recognition of familiar humans and of companion dogs, both of whom had real social interactions with participants. The rostroventral anterior cingulate cortex responded to both species whereas the caudal anterior cingulate cortex was sensitive only to familiar humans. Social cognition processes may be dual-layered: the rostroventral anterior cingulate cortex is associated with fundamental and intuitive aspects, whereas the caudal anterior cingulate cortex is concerned with the analysis of complex social interactions.

Impact of language on functional connectivity for audiovisual speech integration.

Visual information about lip and facial movements plays a role in audiovisual (AV) speech perception. Although this has been widely confirmed, previous behavioural studies have shown interlanguage differences, that is, native Japanese speakers do not integrate auditory and visual speech as closely as native English speakers. To elucidate the neural basis of such interlanguage differences, 22 native English speakers and 24 native Japanese speakers were examined in behavioural or functional Magnetic Resonance Imaging (fMRI) experiments while mono-syllabic speech was presented under AV, auditory-only, or visual-only conditions for speech identification. Behavioural results indicated that the English speakers identified visual speech more quickly than the Japanese speakers, and that the temporal facilitation effect of congruent visual speech was significant in the English speakers but not in the Japanese speakers. Using fMRI data, we examined the functional connectivity among brain regions important for auditory-visual interplay. The results indicated that the English speakers had significantly stronger connectivity between the visual motion area MT and the Heschl's gyrus compared with the Japanese speakers, which may subserve lower-level visual influences on speech perception in English speakers in a multisensory environment. These results suggested that linguistic experience strongly affects neural connectivity involved in AV speech integration.

Load effect on background rhythms during motor execution: A magnetoencephalographic study.

We investigated the effect of load against self-paced movement on cortical involvement for motor execution. Ten right-handed healthy volunteers were requested to perform brisk extension of the right index finger at self-paced intervals exceeding 10s for three load conditions: 0g, 50g and 100g. Movement-related magnetic fields were recorded using an MEG system. The signals were band-pass-filtered through 18-23Hz and rectified before averaging with respect to EMG onset. We analyzed the time course and %change of peak amplitude with reference to the baseline amplitude in event-related desynchronization (ERD) or synchronization (ERS) in each hemisphere. Maximum response was observed around the left somatomotor area for all conditions. ERD did not show any significant difference before the movement onset among the three load conditions. For %change, ERS in the post-movement period was significantly larger for the 100g load condition than for the 0g load condition, and that was significantly greater over the left than over the right hemisphere. These findings indicate that the load has little effect on pre-movement desynchronization, whereas it affects the post-movement synchronization on background rhythms.

A case of venous thoracic outlet syndrome recognized by arm swelling.

Most cases of thoracic outlet syndrome are detected by neulogical symptoms, and most of the other symptoms are caused by arterial stenosis. It is rare for the syndrome to be recognized by venous symptoms. We report a 56-year-old woman with thoracic outlet syndrome recognized by arm swelling. She was admitted for radiation therapy of a recurrent tumor of lung cancer at the left apex. Her right arm gradually became swollen. We performed venography from the right median cubital vein because of suspected venous thrombosis. Venography revealed stenosis of the right subclavian vein at the costoclavicular space, and this finding was confirmed by helical CT. These findings strongly support our diagnosis of thoracic outlet syndrome.

The neural correlates of endowment effect without economic transaction.

People always concern about what they have and what they might lose even it is just imaginary property. According to Prospect Theory, the losses might be weighted by subjects higher than gain, which would cause the disparity between the willingness to accept (WTA) and willingness to pay (WTP) compensation in economic valuation. Using functional MRI, we investigated neural correlates of this inconsistent value estimation, known as the endowment effect, during a simple pricing task without economic transaction. Brain activation associated with this price discrepancy was observed in the right inferior frontal gyrus (IFG), where voxel-based morphometry of MRI revealed the positive correlation between gray matter concentration and WTA/WTP ratio. These findings suggest the functional relevance of IFG in WTA/WTP discrepancy for pricing without any actual gain and loss, where an integration of loss aversion-related signals from insula and expected value signals may occur.

Neural mechanisms involved in mental imagery and observation of gait.

Brain activity during observation and imagery of gait was investigated. Sixteen subjects were scanned with a 3-Tesla MRI scanner while viewing six types of video clips: observation of gait movement (GO) from the third-person perspective, observation of stepping movement, observation of standing posture, "virtual walking" (VW) that was observation of visual scenes mimicking the visual afferent during walking, and the scrambled version of the GO and VW stimuli. In the VW condition, moving scenes provided a virtual visual environment in which subjects easily imagined as if they were actually walking from the first-person perspective. A behavioral experiment revealed a correlation of cadence during actual walking with that during imaginary walking under the influence of the VW stimuli, indicating that a gait planning mechanism was shared by actual walking and gait imagery. The VW condition activated the dorsal premotor cortex (PMd), supplementary motor area/cingulate motor area (SMA/CMA), parahippocampal gyrus, and subcortical nuclei. The GO stimuli yielded activation of the SMA, PMd, inferior frontal gyrus, and inferior parietal lobule. Moreover, the conjunction null test of GO and VW revealed common activity in the SMA/CMA and PMd, which were reportedly active during actual gait movement, in addition to visual areas. Detailed analyses of activity during stepping or standing observation supported the specificity of the SMA and PMd to GO. These findings suggest that motor planning centers of gait, including the SMA and PMd, are activated during both imagination (first-person perspective) and observation (third-person perspective) of gait behaviors.

The neural basis of social tactics: An fMRI study.

One of the most powerful ways of succeeding in complex social interactions is to read the minds of companions and stay a step ahead of them. In order to assess neural responses to reciprocal mind reading in socially strained human relationships, we used a 3-T scanner to perform an event-related functional magnetic resonance imaging study in 16 healthy subjects who participated in the game of Chicken. Statistical parametric mapping showed that the counterpart effect (human minus computer) exclusively activated the medial frontal area corresponding to the anterior paracingulate cortex (PCC) and the supramarginal gyrus neighboring the posterior superior temporal sulcus (STS). Furthermore, when we analyzed the data to evaluate whether the subjects made risky/aggressive or safe/reconciliatory choices, the posterior STS showed that the counterpart had a reliable effect regardless of risky or safe decisions. In contrast, a significant opponent x selection interaction was revealed in the anterior PCC. Based on our findings, it could be inferred that the posterior STS and the anterior PCC play differential roles in mentalizing; the former serves as a general mechanism for mentalizing, while the latter is exclusively involved in socially risky decisions.