Senichiro Kikuchi

Cerebral activation focusing on strong tasting food: a functional magnetic resonance imaging study.

Very little research has been conducted on taste imagery because of the difficulty of doing so. We conducted a functional magnetic resonance imaging study to observe cerebral activation patterns produced in volunteers concentrating on pickled plums (umeboshi), a traditional Japanese food with a strong and sour taste. Activation was observed in the right insula, the bilateral opercula, the bilateral orbitofrontal cortices and the left Brocas area. Activation in the insula (primary gustatory area) was very weak and limited to one side. The activation pattern was similar to that of taste perception. Our results showed that it is possible for humans to imagine tastes.

Cognitive and Psychological Reactions of the General Population Three Months After the 2011 Tohoku Earthquake and Tsunami

Background The largest earthquake on record in Japan (magnitude 9.0) occurred on March 11, 2011, and the subsequent tsunami devastated the Pacific coast of Northern Japan. These further triggered the Fukushima I nuclear power plant accidents. Such a hugely complex disaster inevitably has negative psychological effects on general populations as well as on the direct victims. While previous disaster studies enrolled descriptive approaches focusing on direct victims, the structure of the psychological adjustment process of people from the general population has remained uncertain. The current study attempted to establish a path model that sufficiently reflects the early psychological adaptation process of the general population to large-scale natural disasters. Methods and Findings Participants from the primary disaster area (n = 1083) and other areas (n = 2372) voluntarily participated in an online questionnaire study. By constructing path models using a structural equation model procedure (SEM), we examined the structural relationship among psychological constructs known related to disasters. As post-traumatic stress symptoms (PTS) were significantly more present in people in the primarily affected area than in those in secondary- or non-affected areas, the path models were constructed for the primary victims. The parsimoniously depicted model with the best fit was achieved for the psychological-adjustment centered model with quality of life (QoL) as a final outcome. Conclusion The paths to QoL via negative routes (from negative cognitive appraisal, PTS, and general stress) were dominant, suggesting the importance of clinical intervention for reducing negative cognitive appraisal, and for caring for general stress and PTS to maintain QoL at an early stage of psychological adaptation to a disaster. The model also depicted the presence of a positive route where positive cognitive appraisal facilitates post-traumatic growth (PTG) to achieve a higher QoL, suggesting the potential importance of positive psychological preventive care for unexpected natural disasters.

A study of the relationship between the seizure focus and 1H-MRS in temporal lobe epilepsy and frontal lobe epilepsy

Abstract Several studies of temporal lobe epilepsy (TLE) patients have investigated the relationship between the seizure focus and 1H magnetic resonance spectroscopy (1H‐MRS). There have also been a few reports in other types of partial epilepsy. We examined the relationship between the seizure focus and the reduction in N‐acetylaspartate : creatine (NAA : Cr) ratio using 1H‐MRS in both TLE and frontal lobe epilepsy (FLE) patients. We studied 21 patients with unilateral TLE and seven patients with unilateral FLE. We used a 1.5 Tesla magnetic resonance unit (Signa Horizon; General Electric). Approximately 15 × 15 × 20 mm3 voxel of interest (VOI) was placed over the anterior portion of the bilateral hippocampus in the TLE patients, and the anterodorsal position of bilateral frontal lobe in the FLE patients. The seizure focus was identified by interictal scalp electro‐encephalogram (EEG). In the TLE patients the NAA : Cr ratios were reduced in the seizure focus, while in the FLE patients they were not always reduced in the seizure focus. In the TLE patients the coincidence rate between the seizure focus and the reduction in the NAA : Cr ratio was 90% (19 of 21 patients), while in the FLE patients the coincidence rate was only 57% (four of seven patients).

Basic study of analysis of human brain activities during car driving

Recently, as the worldwide population grows older, it is thought that various assistive systems have soared. It is necessary to discuss functions of humans, spatial perception, decision-making, and determining direction, for developing assistive systems. The final goal of our research is to contribute to developing of welfare robots with functions that are responsive like human. We measured brain activities during virtual car driving using NIRS. As a result of these experiments, there were significant differences at outside frontal cortex in left brain. This go-round, we measured brain activity during actual car driving. In general roads, experiments were performed by taking f-NIRS in the car, and measuring the brain activity when car driven by subjects was went through a number of intersections and road signs. In addition, there was significant difference in common regions. We report a significant association between car driving and brain activity.

Fundamental Study for Relationship between Cognitive Task and Brain Activity During Car Driving

For a long period, many researches about the human spatial recognition are being carried on. They are needed to make robot and automatic driving system for a car or wheelchair and with functions as high as those of humans: spatial perception, decision-making, and determining direction. The final goal of our measuring brain activity research is to contribute to developing of welfare robots with functions that are responsive like human. In this paper, the hemoglobin density change of human frontal lobe is measured. First, to analyze human spatial perception, experiments using a driving movie were designed. In the experiments NIRS (Near Infrared Reflectance Spectroscopy) was used.

Effect of Ventralis Intermedius Thalamotomy on the Area in the Sensorimotor Cortex Activated by Passive Hand Movements: fMR Imaging Study

Stereotactic ventralis intermedius (Vim) thalamotomy is effective for essential tremor (ET) of the limb, but the effect on the activity of the sensorimotor cortex is still unclear. The functional changes in this cortical area of patients with ET after Vim thalamotomy were investigated using functional magnetic resonance (fMR) imaging. Six patients underwent Vim thalamotomy for medically intractable ET, predominantly in the right hand. 1.5-tesla fMR imaging was performed using the blood oxygenation level-dependent sequence, before and after Vim thalamotomy, during passive movements with right wrist flexion and extension. Before and after images were analyzed using SPM99 software. Activation in the sensorimotor cortex and supplementary motor area evoked by wrist passive movement was observed both before and after surgery. Group analysis of changes in the blood oxygenation level-dependent response revealed a significantly smaller activated area postoperatively. Activation at the fundus of the central sulcus was characteristically decreased. All patients showed marked improvement in tremor after Vim thalamotomy. No patient experienced neurological deficits. fMR imaging showed that activation at the fundus of the central sulcus evoked by passive wrist movement was suppressed after Vim thalamotomy in ET patients, probably due to disruption of the thalamocortical pathway. The fundus of the central sulcus (Brodmann area 3a) is likely to be one of the key relays in the tremor circuit.

Alterations in prefrontal cortical activity in the course of treatment for late-life depression as assessed on near-infrared spectroscopy

Aim:  To evaluate the severity of depression by measuring alterations in prefrontal cortical activity associated with mood disorders, as assessed on near‐infrared spectroscopy.

Basic study for a new assistive system based on brain activity associated with spatial perception task during car driving

Our purpose in this research is to contribute to developing of assistive robot and apparatus. Recently, there is a pressing need to develop a new system which assists and acts for car driving and wheelchair for the elderly as the population grows older. In terms of developing a new system, it is thought that it is important to examine behaviors as well as spatial recognition. So, experiments were performed for an examination of human spatial perceptions, especially right and left ones, during car driving using NIRS. In previous research, it has been documented that there were significant differences at dorsolateral prefrontal cortex at left hemisphere during virtual driving. In addition, significant differences were seen at similar regions during actual driving. In this time, detailed analysis about ocular motions was reported. The final goal of this study is to find a way to apply this result to new systems with functions that are responsive like human.

Electroencephalogram‐triggered functional magnetic resonance imaging in focal epilepsy

Abstract  The high spatial resolution and cost performance of functional magnetic resonance imaging (fMRI) is useful for estimating focus localization in epilepsy, but this is difficult in the case of ictal fMRI because this is susceptible to motion artifacts. Electroencephalogram (EEG)‐triggered fMRI, which is interictal, can be performed without marked movement and is thought to be useful, but requires further investigation in order to establish a methodology. The authors studied EEG‐triggered fMRI in partial epileptic patients. Six patients were examined using a Nihon Kohden digital EEG recorder and Signa Horizon High Speed LX 1.5 T MRI scanner. Six electrodes were attached in the vicinity of the focus detected by scalp EEG. The fMRI scans were recorded after the discharges (activation) and scans without spikes (baseline). Equal numbers of activation and baseline scans were collected and analyzed using SPM99. In three of the six patients, an activated area was observed near the focus, but no activated areas were found in the other three subjects who tended to have a low number of spikes and low spike amplitude. Although various approaches focusing on improvement of the activation/non‐activation ratio are required, EEG‐triggered fMRI is a promising technique for detecting focal epileptic brain activity.

Relation between Parametric Change of the Workload and Prefrontal Cortex Activity during a Modified Version of the 'Rock, Paper, Scissors' Task

Background/Aims: Modified rock, paper, scissors (RPS) tasks have previously been used in neuroscience to investigate activity of the prefrontal cortex (PFC). In this study, we investigated hemodynamic changes in the PFC using near-infrared spectroscopy (NIRS) during a modified RPS task in which each subjects successful performance rate was equalized; the workload was increased parametrically in order to reveal the resulting pattern of PFC activation. Methods: The subjects were 20 healthy adults. During RPS, the player uses hand gestures to represent rock, paper, and scissors. Rock beats scissors, paper beats rock, and scissors beats paper. In the modified RPS task, the player is instructed to lose intentionally against the computer hand; the computer goes first and the player follows. The interstimulus interval (ISI) level was adjusted with 11 steps. If the level rose, the ISI decreased and the workload increased parametrically. The maximal level (maxLv: the shortest ISI and the biggest workload) in which a subject could perform the task correctly was determined for every subject during rehearsal of the task prior to the experiment. Lowering the level from the maxLv made the task easier. Hemodynamic changes were measured by NIRS over 4 task levels (maxLv-3, maxLv-2, maxLv-1 and maxLv). Results: The hemodynamic changes in the left lateral PFC and bilateral Brodmann area 6 rose significantly with the increase in workload and presented a linear trend. Conclusion: These results suggest that PFC activation may linearly increase with increased workload during a modified RPS task in which successful performance rates of subjects are equalized.