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Background The brain functional correlates of autobiographical recall are well established, but have been little studied in schizophrenia. Additionally, autobiographical memory is one of a small number of cognitive tasks that activates rather than de-activates the default mode network, which has been found to be dysfunctional in this disorder. Methods Twenty-seven schizophrenic patients and 30 healthy controls underwent functional magnetic resonance imaging while viewing cue words that evoked autobiographical memories. Control conditions included both non-memory-evoking cues and a low level baseline (cross fixation). Results Compared to both non-memory evoking cues and low level baseline, autobiographical recall was associated with activation in default mode network regions in the controls including the medial frontal cortex, the posterior cingulate cortex and the hippocampus, as well as other areas. Clusters of de-activation were seen outside the default mode network. There were no activation differences between the schizophrenic patients and the controls, but the patients showed clusters of failure of de-activation in non-default mode network regions. Conclusions According to this study, patients with schizophrenia show intact activation of the default mode network and other regions associated with recall of autobiographical memories. The finding of failure of de-activation outside the network suggests that schizophrenia may be associated with a general difficulty in de-activation rather than dysfunction of the default mode network per se.

Abnormal interactions between areas of the brain have been pointed as possible causes for schizophrenia. However, the nature of these disturbances and the anatomical location of the regions involved are still unclear. Here, we describe a method to estimate maps of net levels of connectivity in the resting brain, and we apply it to look for differential patterns of connectivity in schizophrenia. This method uses partial coherences as a basic measure of covariability, and it minimises the effect of major physiological noise. When overall (net) connectivity maps of a sample of 40 patients with schizophrenia were compared with the maps from a matched sample of 40 controls, a single area of abnormality was found. It is an area of patient hyper‐connectivity and is located frontally, in medial and orbital structures, clearly overlapping the anterior node of the default mode network (DMN). When this area is used as a region of interest in a second‐level analysis, it shows functional hyper‐connections with several cortical and subcortical structures. Interestingly, the most significant abnormality is found with the caudate, which has a bilateral pattern of abnormality, pointing to a possible DMN–striatum deviant relation in schizophrenia. However, hyper‐connectivity observed with other regions (right hippocampus and amygdala, and other cortical structures) suggests a more pervasive alteration of brain connectivity in this disease. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.

Aims - To further delimit the specific verbal operations occurring in the dorsolateral frontal cortex during the generation of words, methods - different verbal fluency tasks guided by distinct specifications (phonological, semantic, or automatic production of words) were used in a functional magnetic resonance study. The study group comprised 10 right-handed normal subjects ranging in age from 23 to 27 years. Functional magnetic resonance images were obtained in a 1.5-Tesla magnet using a spoiled GRASS sequence. Results - Noticeable activation was found during the word generation tasks in the dorsolateral frontal cortex. The region showing the most prominent activation was the posterior part of the left middle frontal gyrus. Nevertheless, the different tasks each had a different activation effect. The phonologically guided generation of words produced the most consistent activation of the middle frontal gyrus, which mainly involved the premotor cortex. Conclusion - The results suggest that operations concerned with the generation of sound sequences, rather than the amount of produced words or their semantics, are responsible for sustained focal activity observed in the frontal lobes during verbal fluency tasks.

Here we develop a measure of functional connectivity describing the degree of covariability between a brain region and the rest of the brain. This measure is based on previous formulas for the mutual information (MI) between clusters of regions in the frequency domain. Under the current scenario, the MI can be given as a simple monotonous function of the multiple coherence and it leads to an easy visual representation of connectivity patterns. Computationally efficient formulas, adequate for short time series, are presented and applied to functional magnetic resonance imaging (fMRI) data measured in subjects (N=34) performing a working memory task or being at rest. While resting state coherence in high (0.17-0.25 Hz) and middle (0.08-0.17 Hz) frequency intervals is bilaterally salient in several limbic and temporal areas including the insula, the amygdala, and the primary auditory cortex, low frequencies (

This study focused on investigating a possible relationship between interindividual variability in the morphology of the cingulate gyrus and behavioral styles. Using magnetic resonance images obtained from 100 healthy young volunteers (50 women and 50 men), we measured the surface area of the anterior cingulate gyrus and related it to the scores on the Temperament and Character Inventory. Anatomical data revealed that hemispheric asymmetry in the anterior cingulate gyrus surface area was very common (83% of cases) and that a prominent right anterior cingulate was more frequent in women than in men. In the correlational analysis, surface measurements of the right anterior cingulate gyrus accounted for a 24% score variance in Harm Avoidance. Both women and men with larger right anterior cingulate described themselves as experiencing greater worry about possible problems, fearfulness in the face of uncertainty, shyness with strangers, and fatigability. Furthermore, women reported overall higher scores in Harm Avoidance than men; these gender differences were largely explained by gender differences in the right anterior cingulate area in a covariate analysis. Our observations suggest that a large right anterior cingulate is related to a temperamental disposition to fear and anticipatory worry in both genders and that a higher prevalence of these traits in women may be coupled with a greater expansion of this brain region.

The Sylvian fissure region gathers lateral frontotemporal cortices and subcortical structures that are frequently disturbed in patients with mood disorders. We have investigated possible CSF space changes in this brain region in severe melancholic depression. Fifty-seven patients and 37 control subjects received three-dimensional MRI. CSF volumes were obtained for cerebral CSF, lateral ventricles, and both Sylvian fissure regions. As a group, patients showed a significant CSF space enlargement that was prominent around the Sylvian fissure, particularly in the left hemisphere. Likewise, evident leftward asymmetry was more frequent in the patient group (patients 31.6%, controls 2.7%). The combination of CSF space enlargement and the pattern of Sylvian CSF asymmetry predicted the patient condition with 62.2% specificity and 82.5% sensitivity. We conclude that, in the context of a broad severity spectrum of imaging alterations in severe melancholic depression, asymmetrical CSF space enlargement may be evident in the Sylvian fissure region.

Functional imaging has consistently shown that attention-related areas of medial frontal and posterior parietal cortices are active during the attentional conflict induced by color naming in the presence of distracting words (Stroop task). Such studies, however, have provided few details of the correlational nature between observed regional brain activations and reaction time delay occurring in this situation. We analyzed the effect of medial frontal and posterior parietal lesions on the Stroop response in a group of patients with multiple sclerosis, a neurological disorder in which Stroop response speed is affected to varying degrees. Forty-five patients were assessed using a computer-presented verbal version of the Stroop task and specific MRI protocol. Demyelination areas were measured on five anatomical divisions of the medial frontal white matter and on white matter of the posterior parietal lobe. We found that a combination of frontal and parietal lesion measurements accounted for 45% of the Stroop interference time variance. Patients with more right frontal than left parietal demyelination showed slowed Stroop responses, whereas the predominance of lesions in the left posterior parietal region was associated with a reduced Stroop interference. These results may contribute to defining the specific participation of these attention-related brain areas in the conflict of attention represented by the Stroop paradigm. They also help to explain the variability of the Stroop effect in multiple sclerosis patients and suggest that the Stroop test does not assess just a single cognitive operation, but rather the combined effect of anatomically segregated neural processes.

This study was conducted to further establish the significance of the previously reported association between depressive symptoms and demyelinating lesions in the region of the left arcuate fasciculus in multiple sclerosis patients. The Beck Depression Inventory (BDI) was broken down into its main symptom categories on the basis of well-established factor analyses from the literature, and the correlation pattern between the resulting BDI subscores and lesion measurements was analyzed. We found that lesions of the left arcuate fasciculus region were selectively associated with BDI items expressing patients' Affective Symptoms and Somatic Complaints. Specifically, lesion measurements from this brain location accounted for 26% of symptom score variance of the BDI part that includes only these two factors. Performance Difficulties and Cognitive Distortions were not consistently associated with the lesion measurement. Performance Difficulties, however, showed a high correlation with the neurologic deficit detected in the physical examination. These results show that lesions in the left arcuate fasciculus region are associated with the core of the depressive syndrome rather than marginal symptoms and, thus, further suggest that this left suprainsular brain region involves white matter tracts relevant to mood regulation.

Focal hand dystonia in musicians is a strongly task-related movement disorder. Typically, symptoms become apparent only when players execute specific overpracticed skilled exercises on their instrument. We therefore examined five guitarists with functional MRI during dystonic symptom provocation by means of an adapted guitar inside the magnet. The activation patterns obtained in comparable nondystonic guitarists and in the study patients when performing normal-hand exercise served as references. A 1.5-T system equipped with echo-speed gradients and single-shot echoplanar imaging software was used. Data acquisition was centered on the cortical motor system encompassed in eight contiguous slices. Dystonic musicians compared with both control situations showed a significantly larger activation of the contralateral primary sensorimotor cortex that contrasted with a conspicuous bilateral underactivation of premotor areas. Our results coincide with studies of other dystonia types in that they show an abnormal recruitment of cortical areas involved in the control of voluntary movement. However, they do suggest that the primary sensorimotor cortex, rather than being underactive in idiopathic dystonic patients, may be overactive when tested during full expression of the task-induced movement disorder.

Background: Functional imaging studies have demonstrated abnormal patterns of brain activity in obsessive–compulsive disorder, which consistently suggest the alteration of frontal lobe functioning. We performed a brain activation study in obsessive–compulsive disorder using a cognitive task involving the frontal lobes. Methods: Twenty patients and 20 healthy control subjects were assessed with functional magnetic resonance imaging during a phonologically guided word generation task. The study analysis was based on the comparison of group average time-course functional changes occurring at the site of largest frontal cortex activation during alternating rest and task periods. Results: In terms of relative signal changes, patients showed a significantly greater activation during word generation and a defective suppression of this activation during the following rest period. Both abnormal imaging findings significantly correlated with the severity of the clinical process assessed by the Yale–Brown Obsessive–Compulsive Scale. Conclusions: The results indicate that functional magnetic resonance imaging during cognitive challenge may be useful to reveal distinctive features of latent brain dysfunction in obsessive–compulsive disorder.

We studied the effects on CSF dynamics at the foramen magnum and the clinical significance of the abnormal tonsillar motion in 14 patients with Chiari type I malformation and 14 control subjects using cine phase-contrast MRI. Dynamic MRI consisted of axial and sagittal cine phase-contrast sequences. CSF and tonsillar motion were qualitatively and quantitatively evaluated, and the subarachnoid space at the foramen magnum measured. In Chiari patients, cine phase-contrast MRI detected the abnormal pulsatile motion of the cerebellar tonsils, which produced a selective obstruction of CSF flow from the cranial cavity to the spine. The amplitude of the tonsillar pulsation and the severity of the arachnoid space reduction were associated with the symptom of cough-strain headache, but not with the presence of syringomyelia. The finding of abnormal valve dynamics of the cerebellar hernia revealed by cine phase-contrast MRI conforms to the pathophysiologic mechanisms suggested in pressure register studies and opens a new possibility in the presurgical assessment of Chiari patients with exertional symptoms.

INTRODUCTION. Phenylketonuria (PKU) is an autosomal recessive metabolic disease caused by a deficiency of phenylalanine hydroxylase. The dietary therapy for the effective management of PKU, in particular the restriction of high-protein foods of animal-origin, compromises patients' intake of fat and distorts the n-3:n-6 ratio of essential fatty acids in the diet. This deficiency can contribute to neurological and visual impairment. AIM. To evaluate changes in white matter alterations, visual evoked potential (VEP) latencies and performance in executive and motor functions in a group of early and continuously treated PKU patients after supplementation with docosahexaneoic acid (DHA). PATIENTS AND METHODS. We selected 21 PKU patients with early diagnosis (age range: 9-25 years), on a Phe-restricted diet and supplemented with PKU formula. Inclusion criteria were: low erythrocyte DHA values, prolonged P100 wave latencies in VEP and/or presence of white matter hyperintensities on brain magnetic resonance imaging (MRI), and intellectual quotient80. All patients were treated with DHA (10 mg/kg/day) for 12 months. Assessment was conducted at baseline and after 12 months of treatment, and included biochemical parameters, brain MRI, VEP, ophthalmologic evaluation and neuropsychological tests. RESULTS AND CONCLUSION. All the patients normalized the DHA levels after supplementation. Improvement in the P100 wave latencies, and fine motor skills was significant. No significant improvement in the other explorations was evident after supplementation. Further investigations seem advisable to establish a cause-effect relationship between DHA treatment and the slight improvement observed in some neurological functions.

Objectives. Manic patients have been found to show reduced activation in the prefrontal cortex and other regions during performance of cognitive tasks. However, little is known about de-activations associated with the disorder. This study aimed to examine, at the whole-brain level, abnormal patterns of task-related activation and de-activation during performance of a working memory task. Methods. Twenty-nine DSM-IV bipolar patients and 46 healthy controls underwent fMRI during performance of the n-back task. The patients were scanned while they were in a manic episode. Linear models were used to obtain maps of within-group activations and areas of differential activation between the groups. Results. The manic patients showed reduced activation compared to the controls in the bilateral dorsolateral prefrontal cortex and the right parietal cortex. They also showed failure of de-activation in the medial frontal cortex, extending to the temporal poles and parts of the limbic system bilaterally. The failure of activation in the dorsolateral prefrontal cortex disappeared when differences in task performance were controlled for in the analysis. However, the medial frontal failure of de-activation survived controlling for this. Conclusions. This study suggests that, in addition to reduced prefrontal activation, failure of de-activation is an important functional imaging abnormality in mania. This, together with its location in the medial prefrontal cortex, implies default mode network dysfunction in the disorder.

BackgroundCognitive impairment is an established feature of schizophrenia. However, little is known about its relationship to the structural and functional brain abnormalities that characterise the disorder.AimsTo identify structural and/or functional brain abnormalities associated with schizophrenic cognitive impairment.MethodWe carried out structural magnetic resonance imaging (MRI) and voxel-based morphometry in 26 participants who were cognitively impaired and 23 who were cognitively preserved, all with schizophrenia, plus 39 matched controls. Nineteen of those who were cognitively impaired and 18 of those who were cognitively preserved plus 34 controls also underwent functional MRI during performance of a working memory task.ResultsNo differences were found between the participants who were cognitively intact and those who were cognitively impaired in lateral ventricular volume or whole brain volume. Voxel-based morphometry also failed to reveal clusters of significant difference in grey and white matter volume between these two groups. However, during performance of the n-back task, the participants who were cognitively impaired showed hypoactivation compared with those who were cognitively intact in the dorsolateral prefrontal cortex among other brain regions.ConclusionsCognitive impairment in schizophrenia is not a function of the structural brain abnormality that accompanies the disorder but has correlates in altered brain function.

Objective: The efficacy of repetitive transcranial magnetic stimulation (rTMS) of the right prefrontal cortex for patients with obsessive-compulsive disorder (OCD) was studied under double-blind, placebo-controlled conditions. Method: Patients were randomly assigned to 18 sessions of real (N=10) or sham (N=8) rTMS. Treatments lasted 20 minutes, and the frequency was 1 Hz for both conditions, but the intensity was 110% of motor threshold for real rTMS and 20% for the sham condition. Results: No significant changes in OCD were detected in either group after treatment. Two patients who received real rTMS, with checking compulsions, and one receiving sham treatment, with sexual/religious obsessions, were considered responders. Conclusions: Low-frequency rTMS of the right prefrontal cortex failed to produce significant improvement of OCD and was not significantly different from sham treatment. Further studies are indicated to assess the efficacy of rTMS in OCD and to clarify the optimal stimulation characteristics. (Am J Psychiatry 2001; 158:1143–1145) Repetitive transcranial magnetic stimulation (rTMS) has been proposed as therapeutic for different psychiatric disorders, mainly depression, although the stimulation characteristics are still controversial (1–3). Concerning obsessive-compulsive disorder (OCD), Greenberg et al. (4) reported a significant reduction in compulsions during and 8 hours after a single session of right prefrontal rTMS. This study was designed to assess whether prolonged stimulation of the right prefrontal cortex at low frequency would produce significant improvement in a group of OCD patients under double-blind, placebo-controlled conditions.

Iron chelators are a new therapeutical approach for patients with Friedreich’s ataxia, on the basis that oxidative cell damage that occurs in these patients is due to the increasing deposits of mitochondrial iron pools. The objective of the study was to evaluate the effects of the combined therapy of idebenone and low oral doses of deferiprone on the neurological signs and cardiac function parameters. This study was designed as a prospective open-label single-arm study. Twenty Friedreich’s ataxia patients were treated with idebenone (20 mg/kg/day) and deferiprone (20 mg/kg/day) for 11 months. Patients were evaluated before the start and throughout the study with the International Cooperative Ataxia Rating Scale (ICARS) scores, echocardiographic measurements and MRI (magnetic resonance imaging) techniques to asses brain iron deposits in the dentate nucleus. No significant differences were observed in total ICARS scores when comparing baseline status and the end of the study in the whole group of patients. Posture and gait scores increased significantly after 11 months of therapy (Wilcoxon’s test, p = 0.04) and kinetic function improved significantly (Wilcoxon’s test, p = 0.015). Echocardiography data showed a significant reduction of the interventricular septum thickness (Wilcoxon’s test, p = 0.04) and in the left ventricular mass index (Wilcoxon’s test, p = 0.038) after the start of the therapy. The MRI values in the dentate nucleus showed a statistically significant reduction (Wilcoxon’s test p = 0.007) between baseline conditions and after 11 months of the therapy. Combined therapy with idebenone and deferiprone in patients with FDRA indicates a stabilizing effect in neurologic dysfunctions due to an improvement in the kinetic functions, with a worsening of gait and posture scores. Heart hypertrophy parameters and iron deposits in dentate nucleus improved significantly. Combined therapy was well tolerated with mild side effects, apart from the risk of neutropenia and progressive reduction of plasma iron parameters.

Central nervous system (CNS) infections are associated with high morbidity and mortality. Neuroimaging plays an important role in the early diagnosis and characterisation of neurological complications.To report the findings in diffusion-weighted images (DWI) and its potential contribution to the early diagnosis and prognosis of neurological sequelae.Descriptive study of a series of 23 patients, between the ages of 1 month and 16 years, who presented with CNS infection. MRI, with DWI, was performed in all of them.We found 13 viral meningoencephalitis and 10 bacterial meningitis. MRI was performed from day one to seventh after hospitalization. We found CNS affection in conventional MRI and/or DWI in 14 of 23 cases (60%). In three patients the neurological injury was only evident in DWI. We found any type of neurological sequelae in 17 of 21 evaluable patients. The most common neurological sequelae we found was epilepsy (9 of 21). When we related sequelae with conventional MRI and DWI we found a trend in associated more severe sequelae when there are pathological findings in neuroimaging, not statistically significant.DWI sequence can be useful in the early diagnosis of neurological complications in CNS infections.

Neuroimaging studies have found evidence of altered brain structure and function in schizophrenia, but have had complex findings regarding the localization of abnormality. We applied multimodal imaging (voxel-based morphometry (VBM), functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) combined with tractography) to 32 chronic schizophrenic patients and matched healthy controls. At a conservative threshold of P=0.01 corrected, structural and functional imaging revealed overlapping regions of abnormality in the medial frontal cortex. DTI found that white matter abnormality predominated in the anterior corpus callosum, and analysis of the anatomical connectivity of representative seed regions again implicated fibres projecting to the medial frontal cortex. There was also evidence of convergent abnormality in the dorsolateral prefrontal cortex, although here the laterality was less consistent across techniques. The medial frontal region identified by these three imaging techniques corresponds to the anterior midline node of the default mode network, a brain system which is believed to support internally directed thought, a state of watchfulness, and/or the maintenance of one's sense of self, and which is of considerable current interest in neuropsychiatric disorders.

The Val158Met polymorphism in the COMT gene has been found to be associated with differences in brain activation in both healthy subjects and patients with schizophrenia. The predominant finding has been increased prefrontal activation associated with the Val allele; however, genotype-related de-activations have not been studied. In this study 42 schizophrenia patients and 31 controls underwent fMRI while performing the n-back task. Brain differences related to presence/absence of disease and presence/absence of the Val/Val genotype were examined. Both disease and Val/Val genotype were associated with failure of de-activation in a cluster centred in the medial prefrontal cortex. There was no interaction between disease and genotype at this location, but clusters where there were significant interactions emerged in the right prefrontal cortex and left temporal/parietal cortex. These findings suggest that Val158Met polymorphism influences task-related de-activations in the default mode network in both healthy subjects and schizophrenia patients to an equivalent extent. However the Val158Met polymorphism also has disease-specific effects on DLPFC activation in schizophrenia.

Brain creatine (Cr) deficiencies are a group of inborn errors of metabolism that are characterized by an absence or severe reduction of brain Cr. Clinically, these patients can display psychomotor/mental retardation and language disorders, commonly associated with epilepsy or movement disorders. Three metabolic defects are known: two affect synthesis - guanidinoacetate metiltransferase (GAMT) and glycine amidinotransferase (AGAT) deficiencies- and one affect the Cr transporter (CRTR). We present the first three Spanish patients with GAMT deficiency, and we compare their clinical phenotype and treatment response with other published cases.The three patients presented mental retardation, epilepsy and autistic behaviour. Patient 1 also had severe chorea. Diagnosis was done by biochemical and genetic procedures (guanidinoacetate quantification, determination of GAMT activity and mutation analysis in the GAMT gene).An increase of guanidinoacetate was detected in urine and plasma. Brain magnetic resonance spectroscopy revealed low Cr levels. Enzymatic studies revealed a decreased GAMT activity in fibroblasts. Molecular analysis detected pathogenic mutations in the GAMT gene. After the deficiency was confirmed, the patients started treatment with Cr. In addition, patient 2 and 3 received an arginine-restricted diet and ornithine supplements. All them showed a partial improvement.Patients with GAMT deficiency have an unspecific but relatively constant clinical presentation. Brain Cr deficiency should be considered in patients with mental retardation of unknown aetiology, specially in those with movement disorders or epilepsy. Early diagnosis is important in cases with known treatment such as GAMT deficiency.

BackgroundFunctional imaging studies using working memory tasks have documented both prefrontal cortex (PFC) hypo- and hyperactivation in schizophrenia. However, these studies have often failed to consider the potential role of task-related deactivation.MethodThirty-two patients with chronic schizophrenia and 32 age- and sex-matched normal controls underwent functional magnetic resonance imaging (fMRI) scanning while performing baseline, 1-back and 2-back versions of the n-back task. Linear models were used to obtain maps of activations and deactivations in the groups.ResultsThe controls showed activation in the expected frontal regions. There were also clusters of deactivation, particularly in the anterior cingulate/ventromedial PFC and the posterior cingulate cortex/precuneus. Compared to the controls, the schizophrenic patients showed reduced activation in the right dorsolateral prefrontal cortex (DLPFC) and other frontal areas. There was also an area in the anterior cingulate/ventromedial PFC where the patients showed apparently greater activation than the controls. This represented a failure of deactivation in the schizophrenic patients. Failure to activate was a function of the patients' impaired performance on the n-back task, whereas the failure to deactivate was less performance dependent.ConclusionsPatients with schizophrenia show both failure to activate and failure to deactivate during performance of a working memory task. The area of failure of deactivation is in the anterior prefrontal/anterior cingulate cortex and corresponds to one of the two midline components of the ‘default mode network’ implicated in functions related to maintaining one's sense of self.

Using magnetic resonance imaging, we studied 24 patients with ischemic infarction of the internal capsule. Magnetic resonance imaging detected wallerian degeneration of the pyramidal tract below the capsular lesion in 11 patients (45.8%); all 11 had clinical evidence of pyramidal tract damage. In six additional patients magnetic resonance imaging findings, present only on axial slices, were considered to indicate possible wallerian degeneration. When motor deficit was associated with posterior limb lesions, magnetic resonance imaging detected wallerian degeneration of the pyramidal tract in 78.6% (11) of 14 patients.

Depression is a common mood disturbance in multiple sclerosis (MS) patients. Epidemiologic data suggest a causative relationship between depressive symptoms and cerebral demyelination, although a specific lesion site responsible for depressed mood has not been identified. Given that depression in neurologic disease is closely related to frontal and temporal lobe damage, we focused our study on investigating the extent to which lesions in the white matter connecting both cerebral lobes may account for depressive symptoms in MS. Forty-five patients were assessed using the Beck Depression Inventory and an MRI protocol conceived to quantify lesions separately in the basal, medial, and lateral frontotemporal white matter. The presence of lesions in the left suprainsular white matter, the region that mainly includes the arcuate fasciculus, was specifically associated with depressive symptoms, accounting for a significant 17% of the depression score variance. Although a multifactorial origin is suspected for depression in MS, this finding gives support to the existence of a direct negative effect of demyelination on mood.

✓ The ability of functional magnetic resonance (MR) imaging to detect a selective sensorimotor cortex activation in healthy subjects and the feasibility of motor activation in patients with lesions around the central sulcus were investigated. Twenty-five healthy volunteers performed 100 motor activation trials, using a variety of motor tasks, which were monitored by several image analysis methods. The functional images were obtained using a 1.5-tesla standard MR imaging system magnet with blood oxygenation level—dependent contrast. Four patients were assessed using functional MR imaging and invasive cortical mapping. Rolandic cortex activation was observed in 98% of the trials performed on healthy subjects in which no head motion occurred. Nevertheless, the cortical response was not selective in a task-rest analysis due to concurrent activation of neighboring regions. Across-task comparison analyses were useful in canceling nonrelevant activity in most cases (86%). In the patient group, the region identified as the sensorimotor cortex by invasive means corresponded accurately to the area that was activated in functional MR imaging. Present data support the feasibility of detecting selective activation of the rolandic cortex, even in the clinical setting, leading the authors to suggest the usefulness of this widely available technique in surgical planning.

In cirrhotic patients, even in the non-encephalopathic state, MRI may show an increased signal in globus pallidus in T1-weighted sequences, the clinical significance of which is still poorly characterized. A dysfunction of the motor circuit of the basal ganglia might be predicted if the increased MRI signal expressed alterations in the globus pallidus activity. We compared the Bereitschaftspotential (BP) in 15 non-encephalopathic cirrhotic patients and 15 age-matched controls and found that the amplitude of the early component and the peak negativity of the BP before the electromyogram onset were significantly reduced in the patient group. The intensity of the pallidal signal was related to the plasma ammonia level but the amplitudes of the BP were not related to the pallidal signal or to ammonia. These findings indicate that a defective activity of the cortical areas implicated in the preparation of movement, not specifically related to the pallidal signal, can be present in cirrhotic patients, even in the non-encephalopathic state.

Article abstract—We investigated the long-term persistence and short-term stability of globus pallidus (GP) hyperintensity on T1--weighted MRI in 19 cirrhotic patients. After a mean interval of 25.8 months, the hyperintensity of the GP persisted in 17 patients. Hyperintensity disappeared in two patients with hepatocarcinoma, indicating that hyperintensity can revert to normal in circumstances other than liver transplants. Ten patients participated in a 6–month study with repeated evaluations of GP signal intensity, plasma ammonia levels, and selected neuropsychological tests. The GP signal was fairly stable during the follow-up, and the variables considered maintained significant relationships. GP hyperintensity appears as a stable indicator of the functional status of cirrhotic patients.

The aim of the present study was to look for anatomical changes in climbers' brains, using magnetic resonance imaging (MRI), after extremely high-altitude climbs and to relate them to possible associated risk factors. Clinical history, neurological examinations and MRI were carried out on a group of nine climbers before and after climbing to over 7500 m without the use of supplementary oxygen. None of the subjects showed any neurological dysfunctions. In five climbers MRI abnormalities (high signal areas, cortical atrophy) were observed before the expedition. After the descent, two of them showed new high intensity signal areas recorded by MRI. Both subjects suffered severe neurological symptoms during the climb. The present study suggested that the brain changes observed by MRI could be related to the severity of clinical events at high altitude. However, we do not know the exact meaning of such MRI findings or the reason for their location, predominantly in posterior regions of the brain. The new evidence that a high percentage of climbers show MRI brain abnormalities, and especially the appearance of changes after the ascent, reinforces the possibility of a potential neurological risk in high-altitude climbing.

• We studied the functional significance of the involutional and degenerative changes in the substantia nigra as seen on magnetic resonance imaging. The width of the pars compacta correlated with motor performance in both healthy elderly subjects and idiopathic Parkinson's disease groups. Patients exhibited significant reduction of the width of the pars compacta and the level of this reduction correlated strongly with the clinical status evaluated by the Unified Parkinson's Disease Rating Scale. These results suggest that pars compacta shrinkage may account for a substantial part of the structural substratum of motor decline in the elderly. Moreover, an analysis of the relationship of the midbrain damage with specific symptoms in Parkinson's disease could contribute to a better understanding of the pathogenesis of this degenerative process.

• The clinical significance of white matter abnormalities seen in brain imaging studies, termed leuko-araiosis (LA), still remains uncertain. Leuko-araiosis has been associated with a global decline in cognitive performance, although little is known about the cognitive functions that LA may account for. We present the correlates between LA severity on magnetic resonance imaging and mental deterioration in a selected sample of 41 elderly patients with vascular risk factors. We found that LA was related to performance on tasks measuring the speed of information processing and, in particular, on those that involve complex processes. This impairment can be important in producing reduction in daily living activities as it is in the support to the relationship found with some commonly used behavioral rating scales. Leuko-araiosis is also related to the presence of some primitive reflexes, suggesting that their disinhibition may be due to diffuse corticofugal fibers damage.

Objective: To use functional MRI (fMRI) to further define the occurrence of left-hemisphere, bilateral, and right-hemisphere language in a normal left-handed population. Methods: A total of 100 healthy volunteers, consisting of 50 left-handed subjects and a reference group of 50 right-handed subjects, were studied by fMRI of the frontal cortex during silent word generation. Results: Ninety-six percent of right-handed subjects showed fMRI changes lateralized to the left hemisphere, whereas 4% showed a bilateral activation pattern. In contrast, left-hemisphere lateralization occurred in 76% of left-handers, bilateral activation in 14%, and right-hemisphere lateralization in the remaining 10%. The predominance of right-hemisphere activation, however, was weak in these cases; only a single left-handed subject (2%) showed complete right-hemisphere lateralization. Conclusions: Silent word generation lateralizes to the left cerebral hemisphere in both handedness groups, but right-hemisphere participation is frequent in normal left-handed subjects. Exclusive right-hemisphere activation rarely occurred in the frontal lobe region studied.

In cirrhotic patients, even in a stable nonencephalopathic state, MRI may show cerebral atrophy and increased signal in globus pallidus on T1-weighted sequences. We investigated the relationship between cerebral atrophy and increased pallidal signal and the clinical status of 30 cirrhotic patients. We found a weak association between the two MRI findings. There were different patterns of clinical variables related to the imaging findings. Performance on motor tasks involving speed correlated with the pallidal signal and plasma ammonia levels but not with atrophy. Test results for memory and frontal-premotor function were associated with brain atrophy but not with the pallidal signal or with ammonia.

Background Although there are undeniable diagnostic benefits of CT scanning, its increasing use in paediatric radiology has become a topic of concern regarding patient radioprotection. Objective To assess the rate of CT scanning in Catalonia, Spain, among patients younger than 21 years old at the scan time. Materials and methods This is a sub-study of a larger international cohort study (EPI-CT, the International pediatric CT scan study). Data were retrieved from the radiological information systems (RIS) of eight hospitals in Catalonia since the implementation of digital registration (between 1991 and 2010) until 2013. Results The absolute number of CT scans annually increased 4.5% between 1991 and 2013, which was less accentuated when RIS was implemented in most hospitals. Because the population attending the hospitals also increased, however, the rate of scanned patients changed little (8.3 to 9.4 per 1,000 population). The proportions of patients with more than one CT and more than three CTs showed a 1.51- and 2.7-fold increase, respectively, over the 23 years. Conclusion Gradual increases in numbers of examinations and scanned patients were observed in Catalonia, potentially explained by new CT scanning indications and increases in the availability of scanners, the number of scans per patient and the size of the attended population. Supported in part by the Seventh Framework Programme from the European Community (Grant agreement no: 269912) and the Consejo de Seguridad Nuclear.

Object. The authors sought to evaluate the advantages and limitations of functional magnetic resonance (fMR) imaging when it was used regularly in the clinical context to identify the central sulcus. Methods. A 1.5-tesla MR system comprising a spoiled gradient recalled acquisition in the steady-state functional sequence and a cross-hand cancellation analysis method were used to evaluate 50 surgical candidates with centrally located space-occupying lesions in the brain. Three-dimensional (3-D) models of the patient's head and brain showing the relative position of the tumor and the eloquent cortex were obtained in each case. A selective and reproducible focal activation was found, indicating the probable central sulcus position in 41 patients (82%). Direct cortical stimulation confirmed the fMR findings in 100% of 22 intraoperatively assessed patients. Failure to identify the central sulcus occurred in 18% of cases and was mainly a consequence of intrinsic damage in the primary sensorimotor region that resulted in severe hand paresis. Conclusions. Although specific factors were identified that contributed to reduced sensitivity of fMR imaging in the clinical context, the present study supports functional assessment and 3-D representation of specific surgical situations as generally feasible in common practice.