Brain activity associated with the rubber foot illusion.

The internal representation of the body is constantly updated by sensory information based on interactions with the environment. The internal representation of the hand can be experimentally manipulated with the rubber hand illusion (RHI) paradigm. Brain activity during the RHI provides insight into the neural mechanisms underpinning the reconstruction of the internal representation of the hand. Recently, the RHI paradigm has been employed for the lower limb, revealing that the illusion is also induced in the lower limb (rubber foot illusion; RFI). However, the neural correlates of the RFI remain unknown. We used functional magnetic resonance imaging (fMRI) to examine brain activity during the RFI. Forty-four healthy volunteers participated in the fMRI experiment. Significant increases in activation were observed in the bilateral medial and middle frontal gyri, left supplemental motor area, bilateral inferior parietal lobuli, precunei, calcarine cortices, and cerebellar hemispheres; and in the vermis and bilateral thalami during the right RFI. During the left RFI, significant increases in activation were observed in the bilateral medial, middle, and superior frontal gyri; left inferior frontal gyrus and supplemental motor area, bilateral inferior parietal lobuli and middle temporal gyri, and in the left cerebellar hemisphere, vermis, and bilateral thalami. Conjunction analysis revealed that the prefrontal cortex including the bilateral medial and middle frontal gyri, parietal cortex including the bilateral inferior parietal lobuli, and cerebellum including the bilateral cerebellar hemispheres and vermis were conjointly activated during the right and left RFIs. The distribution of co-activated brain areas during the RFI was similar to the previously reported distribution of brain areas activated during the RHI. Co-activation of these brain areas may be associated with the reconstruction of the internal representation of the body. The fact that these areas are activated both in the RFI and RHI will have implications for the treatment of patients with disturbed internal bodily representation.

Aneurysm location and clipping versus coiling for development of secondary normal-pressure hydrocephalus after aneurysmal subarachnoid hemorrhage: Japanese Stroke DataBank.

OBJECT: The present study aimed to investigate aneurysm locations and treatments for ruptured cerebral aneurysms associated with secondary normal-pressure hydrocephalus (sNPH) after subarachnoid hemorrhage (SAH) by using comprehensive data from the Japanese Stroke DataBank. METHODS: Among 101,165 patients with acute stroke registered between 2000 and 2013, 4693 patients (1482 men, 3211 women) were registered as having had an SAH caused by a ruptured saccular aneurysm. Of them, 1448 patients (438 men and 1010 women; mean age 61.9 ± 13.4 years) who were confirmed to have or not have coexisting acute hydrocephalus and sNPH were included for statistical analyses. Locations of the ruptured aneurysms were subcategorized into 1 of the following 4 groups: middle cerebral artery (MCA; n = 354), anterior communicating artery and anterior cerebral artery (ACA; n = 496), internal carotid artery (ICA; n = 402), and posterior circulation (n = 130). Locations of 66 of the ruptured aneurysms were unknown/unrecorded. Treatments included craniotomy and clipping alone in 1073 patients, endovascular coil embolization alone in 285 patients, and a combination of coiling and clipping in 17 patients. The age-adjusted and multivariate odds ratios from logistic regression analyses were calculated after stratification using the Fisher CT scale to investigate the effects of the hematoma volume of SAH. RESULTS: Acute hydrocephalus was confirmed in 593 patients, and 521 patients developed sNPH. Patients with a ruptured ACA aneurysm had twice the risk for sNPH over those with a ruptured MCA aneurysm. Those with an ACA aneurysm with Fisher Grade 3 SAH had a 9-fold-higher risk for sNPH than those with an MCA aneurysm with Fisher Grade 1 or 2 SAH. Patients with a ruptured posterior circulation aneurysm did not have any significant risk for sNPH. Clipping of the ruptured aneurysm resulted in twice the risk for sNPH over coil embolization alone. CONCLUSIONS: Patients with low-grade SAH caused by a ruptured MCA aneurysm had a low risk for the development of sNPH. In contrast, patients with high-grade SAH caused by a ruptured ACA aneurysm had a higher risk for sNPH. Endovascular coiling might confer a lower risk of developing sNPH than microsurgical clipping.

[Support for the medication monitoring of patients with alzheimer's dementia by the interactive care system using IT].

In our laboratory, we draw up research aims to improve medication compliance in patients with dementia by video phone, and we have intervened in the cases of 3 patients to date. In this study, we focused on patients who are using a rivastigmine patch for Alzheimer' disease, which can be confirmed by video phone, to examine its efficacy. Specifically, by monitoring the effects of the treatment, skin side effects, of skin and usability for patients and caregivers, we monitor the dosing schedule to prevent interruption of self-medication, with the aim of improving compliance and treatment efficacy. We also consider methods of intervention for increasing the persistence rate of the rivastigmine patch and quality of life(QOL)by using the effectiveness of the video phone to focus on the symptoms of skin side effects. In addition, we examine the interventions that reduce the care burden and anxiety of caregivers by listening during the regular intervention.

Brain activation during autobiographical memory retrieval with special reference to default mode network.

Recent neuroimaging studies have suggested that brain regions activated during retrieval of autobiographical memory (ABM) overlap with the default mode network (DMN), which shows greater activation during rest than cognitively demanding tasks and is considered to be involved in self-referential processing. However, detailed overlap and segregation between ABM and DMN remain unclear. This fMRI study focuses first on revealing components of the DMN which are related to ABM and those which are unrelated to ABM, and second on extracting the neural bases which are specifically devoted to ABM. Brain activities relative to rest during three tasks matched in task difficulty assessed by reaction time were investigated by fMRI; category cued recall from ABM, category cued recall from semantic memory, and number counting task. We delineated the overlap between the regions that showed less activation during semantic memory and number counting relative to rest, which correspond to the DMN, and the areas that showed greater or less activation during ABM relative to rest. ABM-specific activation was defined as the overlap between the contrast of ABM versus rest and the contrast of ABM versus semantic memory. The fMRI results showed that greater activation as well as less activation during ABM relative to rest overlapped considerably with the DMN, indicating that the DMN is segregated to the regions which are functionally related to ABM and the regions which are unrelated to ABM. ABM-specific activation was observed in the left-lateralized brain regions and most of them fell within the DMN.

Gender differences in brain activation during encoding and recognition of male and female faces.

Although behavioral studies have suggested that there are gender differences regarding facial recognition, the neural substrates of these differences have not been fully examined. In order to clarify them, we performed a functional magnetic resonance imaging (fMRI) experiment in which participants encoded and recognized male and female faces. Behaviorally, the facial recognition ability of men and women was similar, and was superior for female faces compared to male faces. At the neural level, widespread areas showed greater responses for men vs. women during the encoding and recognition phase, and several areas, including the hippocampal region, showed greater responses to female vs. male faces during recognition. The reduced activation of women's brains during encoding and recognition suggests that the relevant neural systems were more efficiently recruited in women than in men.

Differential activation of the striatum for decision making and outcomes in a monetary task with gain and loss.

We examined brain activation for decision making and for different monetary outcomes in a two-alternative choice task with monetary rewards and punishments. Brain hemodynamic changes were monitored by functional MRI (fMRI) when seventeen healthy volunteers performed a task in which they were required to press one of two buttons (button 1 or 2) which increased or decreased their previously endowed money depending upon accord or disaccord with the number (1 or 2) which was displayed later. The amount of money subjects gained or lost was large when they selected 2 and small when they selected 1. They were informed in advance that the order of the appearance of 1 or 2 at outcome phase was predetermined and random, irrespective of their selection, and that the expected value was mathematically zero for both selecting 1 and 2. Results of fMRI showed that bilateral putamen and nucleus accumbens were more activated when selecting large gain or loss option than selecting small gain or loss option, and the right putamen and nucleus accumbens were more activated for gain outcome than for loss outcome. No significantly different activation of the striatum was found between large gain outcome and small gain outcome, suggesting that activity of the striatum at outcome phase was insensitive for reward magnitude when expectation by subject was already performed. We also found that activations of the bilateral putamen were correlated parametrically with stock amount of money.

Successful treatment of plasma exchange for severe cerebral venous thrombosis with thyrotoxicosis.

Although cerebral venous thrombosis (CVT) is generally treated with anticoagulants, some patients have a poor prognosis. We report a 34-year-old woman who developed severe CVT with mental symptoms and intracerebral hemorrhage with central herniation. She had a hypercoagulable state accompanied by thyrotoxicosis. Aggressive medical therapies including unfractionated heparin, a mixture of concentrated glycerin and fructose, and intravenous administration of thiamazole, iohexol, and propranolol were ineffective. The patient was treated with plasma exchange (PE) two times, in addition to aggressive medical therapies. The neurologic symptoms and laboratory data including high levels of thyroid hormones began to improve soon after the first PE. Activated partial thromboplastin time was prolonged after PE although the heparin dose was not changed. After 6 months, her modified Rankin Scale score was 2. PE should be considered for severe CVT as a result of a hypercoagulable state accompanied by thyrotoxicosis, because it not only reduces thyroid hormones, but also might remove multiple prothrombotic factors.

Recognition and reading aloud of kana and kanji word: an fMRI study.

It has been proposed that different brain regions are recruited for processing two Japanese writing systems, namely, kanji (morphograms) and kana (syllabograms). However, this difference may depend upon what type of word was used and also on what type of task was performed. Using fMRI, we investigated brain activation for processing kanji and kana words with similar high familiarity in two tasks: word recognition and reading aloud. During both tasks, words and non-words were presented side by side, and the subjects were required to press a button corresponding to the real word in the word recognition task and were required to read aloud the real word in the reading aloud task. Brain activations were similar between kanji and kana during reading aloud task, whereas during word recognition task in which accurate identification and selection were required, kanji relative to kana activated regions of bilateral frontal, parietal and occipitotemporal cortices, all of which were related mainly to visual word-form analysis and visuospatial attention. Concerning the difference of brain activity between two tasks, differential activation was found only in the regions associated with task-specific sensorimotor processing for kana, whereas visuospatial attention network also showed greater activation during word recognition task than during reading aloud task for kanji. We conclude that the differences in brain activation between kanji and kana depend on the interaction between the script characteristics and the task demands.

An FMRI study of word reading and colour recognition in different quadrant fields.

This fMRI study analyzed activations for processing of word and colour, which were presented in each of the four quadrants, to investigate anatomical segregation between colour and orientation processing and also to examine the effect of visual stimulus position on brain activations. Main effect of visual category was found in the bilateral extrastriate cortices extending to the left visual word form area (word > colour) and small area of the right ventrolateral prefrontal cortex (colour > word). ROI analysis showed that there was a tendency that V4alpha, not V4/8, showed a greater response to colours than to words. Main effect of visual fields was found in early visual areas, which showed greater responses to the left than to the right field stimuli and also to the lower than to the upper field stimuli. No significant interactions between visual category and visual fields were found.

Longitudinal fMRI study of reading in a patient with letter-by-letter reading.

The present study provides a longitudinal fMRI study of reading 7 days after a hemorrhage in the left basal occipito-temporal region when the patient showed letter-by-letter (LBL) reading, and repeated again 50 days after onset, when his LBL reading had resolved. Direct comparison of the two sessions showed that right homologue of the so called visual word form area (VWFA), as well as a network related to language and verbal working memory, such as the bilateral premotor areas, Broca's area and its right homologue, and the left supplementary motor area were more strongly activated when his LBL reading persisted than when he recovered, whereas perilesional activity around the VWFA and the activity of superior part of the left superior parietal lobule were more strongly activated when he recovered than when his LBL reading persisted. These results suggest that dynamic functional reorganization of the brain was caused in the acute phase and that the increased activation of certain areas in the left superior parietal lobule in addition to the VWFA may be related to recovery from LBL reading.

Transient directional disorientation as a manifestation of cerebral ischemia.

The authors describe 2 patients who presented with transient directional disorientation (TDD) as a manifestation of cerebral ischemia. The patients suddenly lost sense of direction in a familiar environment despite preserved ability to recognize landmarks, and recovered within a short time. Brain MRI revealed an ischemic lesion in the right medial occipital lobe and the corpus callosum in case 1 and in the right parieto-occipital sulcus (POS) in case 2. After ictus, fMRI study of a navigation task was performed, which demonstrated the activation of the POS unilaterally in case 1 and bilaterally in case 2. We propose that TDD of our patients is related to temporary dysfunction of bilateral POS.

Directional disorientation following left retrosplenial hemorrhage: a case report with fMRI studies.

We report a 55-year-old right-handed man who presented with topographical disorientation following left retrosplenial hemorrhage. His directional information about familiar places, encoded by previous navigation, was severely impaired, and he could not learn the direction to new places in large-scale spaces beyond the range of visual surveillance. By contrast, he had no difficulties with directional information encoded in a tabletop manner: he could locate major cities or countries on a map, and he also could memorize the spatial relationship of objects in a room. Six months after the ictus, when he had recovered from his directional disorientation, a functional magnetic resonance imaging (fMRI) study of mental navigation demonstrated prominent activation in the retrosplenial area along the right parieto-occipital sulcus and the circumference of the injured area on the left side. The present study, together with previous investigations including clinical case reports, functional neuroimaging, and anatomical and physiological studies on monkeys, suggests that the 'sense of direction' in a large-scale locomotor environment is subserved by the visual area along the parieto-occipital sulcus, and that bilateral deterioration of this function causes directional disorientation.

Somatotopy of corticospinal tract in the internal capsule shown by functional MRI and diffusion tensor images.

Using functional MRI and diffusion tensor tractography, we studied the topographical relation of hand and foot fibers of the corticospinal tract within the internal capsule to verify the recent unexpected finding by Holodny et al., who reported that hand fibers are located anterolateral to foot fibers, not anteromedial as is currently believed. The location of hand fibers with respect to foot fibers was anterolateral in four participants, posterolateral in two, and anteromedial in one of seven participants examined. Thus, there was some support for the anterolateral finding of Holodny et al., but interindividual variability was also indicated.

Neural substrates of the performance of an auditory verbal memory: between-subjects analysis by fMRI.

We studied the neural correlates for the performance of auditory verbal memory using fMRI in 28 normal right-handed volunteers who had to encode and retrieve 50 related word-pair associates. Since the effectiveness of encoding and retrieval processes contribute to memory performance, we combined them in one analysis in addition to examining each condition. Between-subjects analyses were performed by a two-sample t-test in which brain activation in the good-performance group was compared with that of the poor-performance group. Regression analysis was also carried out to find the regions whose activations were linearly correlated to the number of correct recalls by all subjects. In addition to the positive correlates of memory performance, the areas whose activations have a negative effect were also examined. The results indicate that the brain networks of positive correlates including the parahippocampal gyrus and negative correlates including the right prefrontal cortex constitute neural substrates for the performance of auditory verbal memory.

Reverse sequencing syllables of spoken words activates primary visual cortex.

Using fMRI, we investigated the neural correlates for sequencing the individual syllables of spoken words in reverse order. The comparison of this task to a control task requiring subjects to repeat identical syllables given acoustically revealed the activation of the primary visual cortex. Because one syllable is generally expressed by one kana character (Japanese phonogram), most subjects used a strategy in which the kana character string corresponding to the word was imagined visually and then read mentally in reverse order to perform the task effectively. Such strategy was not used during a control condition. These results suggest that the primary visual cortex plays a role in the generation of an imagined string.

Parieto-frontal networks for clock drawing revealed with fMRI.

We studied the neural substrates of clock drawing using functional magnetic resonance imaging in 18 right-handed volunteers. In the test condition, subjects were required to draw the hands of a clock corresponded to the time presented acoustically. In the control task, they drew horizontal and vertical lines after reciting silently the numerals of three figures presented acoustically. In group analyses, comparison between the test and control condition revealed brain areas related to clock drawing; bilateral posterior parietal cortices with a right side dominance, bilateral dorsal premotor areas, the left pre-supplementary motor area, the left ventral prefrontal cortex, the left precentral gyrus, and bilateral cerebellum. In particular, the posterior parietal cortex and the dorsal premotor area, which were strongly activated in all 18 subjects examined in individual analyses, appear to be the main constituent of the parieto-frontal cortical networks for clock drawing.

Mental navigation in humans is processed in the anterior bank of the parieto-occipital sulcus.

We examined the brain regions which were activated during mental navigation; functional magnetic resonance imaging was performed in 16 right-handed male volunteers. The anterior bank of the parieto-occipital sulcus (APO) was strongly activated in all 16 subjects examined. In group study, the retrosplenial area, the bilateral angular gyrus/occipital cortex junction, the left superior premotor area, the right parahippocampal gyrus, and the right cerebellum were activated commonly across 16 subjects. The APO region activated during mental navigation appeared to be equivalent to the visual area V6A in monkeys and to subserve egocentric spatial processes.