Evening preference correlates with regional brain volumes in the anterior occipital lobe.

Chronotype or diurnal preference is a questionnaire-based measure influenced both by circadian period and by the sleep homeostat. In order to further characterize the biological determinants of these measures, we used a hypothesis-free approach to investigate the association between the score of the morningness-eveningness questionnaire (MEQ) and the Munich chronotype questionnaire (MCTQ), as continuous variables, and volumetric measures of brain regions acquired by magnetic resonance imaging (MRI). Data were collected from the Baependi Heart Study cohort, based in a rural town in South-Eastern Brazil. MEQ and anatomical 1.5-T MRI scan data were available from 410 individuals, and MCTQ scores were available from a subset of 198 of them. The average MEQ (62.2 ± 10.6) and MCTQ (average MSFsc 201 ± 85 min) scores were suggestive of a previously reported strong general tendency toward morningness in this community. Setting the significance threshold at P > .002 to account for multiple comparisons, we observed a significant association between lower MEQ score (eveningness) and greater volume of the left anterior occipital sulcus (ß = -0.163, p = .001) of the occipital lobe. No significant associations were observed for MCTQ. This may reflect the smaller dataset for MCTQ, and/or the fact that MEQ, which asks questions about preferred timings, is more trait-like than the MCTQ, which asks questions about actual timings. The association between MEQ and a brain region dedicated to visual information processing is suggestive of the increasingly recognized fluidity in the interaction between visual and nonvisual photoreception and the circadian system, and the possibility that chronotype includes an element of masking.

Dynamic regulation of interregional cortical communication by slow brain oscillations during working memory.

Transiently storing information and mentally manipulating it is known as working memory. These operations are implemented by a distributed, fronto-parietal cognitive control network in the brain. The neural mechanisms controlling interactions within this network are yet to be determined. Here, we show that during a working memory task the brain uses an oscillatory mechanism for regulating access to prefrontal cognitive resources, dynamically controlling interactions between prefrontal cortex and remote neocortical areas. Combining EEG with non-invasive brain stimulation we show that fast rhythmical brain activity at posterior sites are nested into prefrontal slow brain waves. Depending on cognitive demand this high frequency activity is nested into different phases of the slow wave enabling dynamic coupling or de-coupling of the fronto-parietal control network adjusted to cognitive effort. This mechanism constitutes a basic principle of coordinating higher cognitive functions in the human brain.

Heritability of semantic verbal fluency task using time-interval analysis.

Individual variability in word generation is a product of genetic and environmental influences. The genetic effects on semantic verbal fluency were estimated in 1,735 participants from the Brazilian Baependi Heart Study. The numbers of exemplars produced in 60 s were broken down into time quartiles because of the involvement of different cognitive processes-predominantly automatic at the beginning, controlled/executive at the end. Heritability in the unadjusted model for the 60-s measure was 0.32. The best-fit model contained age, sex, years of schooling, and time of day as covariates, giving a heritability of 0.21. Schooling had the highest moderating effect. The highest heritability (0.17) was observed in the first quartile, decreasing to 0.09, 0.12, and 0.0003 in the following ones. Heritability for average production starting point (intercept) was 0.18, indicating genetic influences for automatic cognitive processes. Production decay (slope), indicative of controlled processes, was not significant. The genetic influence on different quartiles of the semantic verbal fluency test could potentially be exploited in clinical practice and genome-wide association studies.

Author Correction: Post-stroke insomnia in community-dwelling patients with chronic motor stroke: Physiological evidence and implications for stroke care.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Metabolic syndrome alters relationships between cardiometabolic variables, cognition and white matter hyperintensity load.

Cardiometabolic risk factors influence white matter hyperintensity (WMH) development: in metabolic syndrome (MetS), higher WMH load is often reported but the relationships between specific cardiometabolic variables, WMH load and cognitive performance are uncertain. We investigated these in a Brazilian sample (aged 50-85) with (N = 61) and without (N = 103) MetS. Stepwise regression models identified effects of cardiometabolic and demographic variables on WMH load (from FLAIR MRI) and verbal recall performance. WMH volume was greater in MetS, but verbal recall performance was not impaired. Age showed the strongest relationship with WMH load. Across all participants, systolic blood pressure (SBP) and fasting blood glucose were also contributors, and WMH volume was negatively associated with verbal recall performance. In non-MetS, higher HbA1c, SBP, and number of MetS components were linked to poorer recall performance while higher triglyceride levels appeared to be protective. In MetS only, these relationships were absent but education exerted a strongly protective effect on recall performance. Thus, results support MetS as a construct: the clustering of cardiometabolic variables in MetS alters their individual relationships with cognition; instead, MetS is characterised by a greater reliance on cognitive reserve mechanisms. In non-MetS, strategies to control HbA1c and SBP should be prioritised as these have the largest impact on cognition.

Post-stroke insomnia in community-dwelling patients with chronic motor stroke: Physiological evidence and implications for stroke care.

Questionnaire studies suggest that stroke patients experience sustained problems with sleep and daytime sleepiness, but physiological sleep studies focussing specifically on the chronic phase of stroke are lacking. Here we report for the first time physiological data of sleep and daytime sleepiness obtained through the two gold-standard methods, nocturnal polysomnography and the Multiple Sleep Latency Test. Data from community-dwelling patients with chronic right-hemispheric stroke (>12 months) were compared to sex- and age-matched controls. Behavioural and physiological measures suggested that stroke patients had poorer sleep with longer sleep latencies and lower sleep efficiency. Patients further spent more time awake during the night, and showed greater high-frequency power during nonREM sleep than controls. At the same time the Multiple Sleep Latency Test revealed greater wake efficiency in patients than controls. Importantly these findings were not due to group differences in sleep disordered breathing or periodic limb movements. Post-stroke insomnia is presently not adequately addressed within the care pathway for stroke. A holistic approach to rehabilitation and care provision, that includes targeted sleep interventions, is likely to enhance long-term outcome and quality of live in those living with chronic deficits after stroke.

Models to Tailor Brain Stimulation Therapies in Stroke.

A great challenge facing stroke rehabilitation is the lack of information on how to derive targeted therapies. As such, techniques once considered promising, such as brain stimulation, have demonstrated mixed efficacy across heterogeneous samples in clinical studies. Here, we explain reasons, citing its one-type-suits-all approach as the primary cause of variable efficacy. We present evidence supporting the role of alternate substrates, which can be targeted instead in patients with greater damage and deficit. Building on this groundwork, this review will also discuss different frameworks on how to tailor brain stimulation therapies. To the best of our knowledge, our report is the first instance that enumerates and compares across theoretical models from upper limb recovery and conditions like aphasia and depression. Here, we explain how different models capture heterogeneity across patients and how they can be used to predict which patients would best respond to what treatments to develop targeted, individualized brain stimulation therapies. Our intent is to weigh pros and cons of testing each type of model so brain stimulation is successfully tailored to maximize upper limb recovery in stroke.

Short-term learning of a visually guided power-grip task is associated with dynamic changes in EEG oscillatory activity.

OBJECTIVE: Performing a motor task after a period of training has been associated with reduced cortical activity and changes in oscillatory brain activity. Little is known about whether learning also affects the neural network associated with motor preparation and post movement processes. Here we investigate how short-term motor learning affects oscillatory brain activity during the preparation, execution, and post-movement stage of a force-feedback task. METHODS: Participants performed a visually guided power-grip tracking task. EEG was recorded from 64 scalp electrodes. Power and coherence data for the early and late stages of the task were compared. RESULTS: Performance improved with practice. During the preparation for the task alpha power was reduced for late experimental blocks. A movement execution-related decrease in beta power was attenuated with increasing task practice. A post-movement increase in alpha and lower beta activity was observed that decreased with learning. Coherence analysis revealed changes in cortico-cortical coupling with regard to the stage of the visuomotor task and with regard to learning. Learning was variably associated with increased coherence between contralateral and/or ipsilateral frontal and parietal, fronto-central, and occipital brain regions. CONCLUSIONS: Practice of a visuomotor power-grip task is associated with various changes in the activity of a widespread cortical network. These changes might promote visuomotor learning. SIGNIFICANCE: This study provides important new evidence for and sheds new light on the complex nature of the brain processes underlying visuomotor integration and short-term learning.

An MRI compatible visual force-feedback system for the study of force control mechanics.

Motor task experiments play an essential role in exploring the brain mechanisms of movement control, and visual force-feedback is an important factor in these motor experiments. In this paper, the authors proposed a visual forcefeedback system suitable for neuroscience experiment. With this system, the force output produced by participants can be detected and recorded in real time, while force output was visually displayed as a feedback cue to the participants simultaneously. Furthermore, this force feedback system is MRI compatible, and can be used both in fMRI and ERP experiments. The proposed system has been applied in handgrip tasks and finger movement experiments, which were designed to explore the relationship between force output and brain activation mode in normal subject and stroke patient. The results demonstrated that various force levels were well detected and visual feedback signals enabled the accomplishment of experiments with both fixed and variable target force levels.

A template effect study on voxel-based morphometry in statistic parametric mapping.

Voxel-based morphometry (VBM) is an automated method allowing identification of anatomical differences in the whole brain without the pre-specification of a region of interests. Spatial normalization is one of the major processes in VBM, which transforms all images to a standard template. A variety of templates were employed in VBM researches in the literature, including the MNI template and study-specific templates. Few studies were presented to test the effect of templates on the detection accuracy of VBM, although it is claimed in many papers that the study-specific template performs better. However, the creation of the study-specific template differs on the subjects included. In this paper, the gray matter (GM) difference of two groups (female vs male) was analyzed to evaluate the effects of templates on the VBM results. The statistic parametric mapping (SPM) package, as the standard software for VBM implementation, was used for analyses.

Intensity Non-uniformity Correction of Magnetic Resonance Images Using a Fuzzy Segmentation Algorithm.

Artifacts in magnetic resonance images can make conventional intensity-based segmentation methods very difficult, especially for the spatial intensity non-uniformity induced by the radio frequency (RF) coil. The non-uniformity introduces a slow-varying shading artifact across the images. Many advanced techniques, such as nonparametric, multi-channel methods, cannot solve the problem. In this paper, the extension of an improved fuzzy segmentation method, based on the traditional fuzzy c-means (FCM) algorithm and neighborhood attraction, is proposed to correct the intensity non-uniformity. Experimental results on both synthetic non-MR and MR images are given demonstrate the superiority of the algorithm.

Exploring a repetitive training regime for upper limb hemiparesis in an in-patient setting: a report on three case studies.

PRIMARY OBJECTIVE: To explore the efficacy of a task-oriented repetitive training protocol (RTx) in chronic hemiparetic patients in an in-patient rehabilitation unit. RESEARCH DESIGN: Three case studies; ABAB design (A=RTx; B=regular rehabilitation programme; 1 week per phase, respectively) in case P1, pre-post intervention comparison in case P2; repeated measure design in case P3. METHODS AND PROCEDURES: Daily training of task-oriented affected hand movements using shaping procedures developed in Constraint-Induced (CI) Movement Therapy. Patients 1 and 2 were trained daily for 90 minutes over 2 weeks. Patient 3 received 60 minutes of daily training for a period of 4 weeks. Outcome measures were Wolf Motor Function Test (WMFT), Frenchay Arm Test, nine-hole peg test, upper extremity MRC, and grip force. MAIN OUTCOMES AND RESULTS: Substantial clinical benefits were achieved in all patients. The subjective observations mirrored significant improvements in the outcome parameters. CONCLUSION: The affected hand training improves upper limb motor functions in chronic patients. It is a 'practicable' approach for in-patient rehabilitation units.

[Clinical relevance and treatment possibilities of rapid cycling in patients with bipolar disorder]. / Klinische Relevanz und Behandlungsmöglichkeiten von Rapid Cycling bei Patienten mit bipolarer affektiver Störung.

In the actual version of the WHO diagnostic guidelines, the ICD-10, subtypes of bipolar disorder are not specified, in contrast to the American DSM-IV, where bipolar disorder has already been differentiated in bipolar I (severe manic and depressive episodes) and bipolar II disorder (depressive and hypomanic episodes). Furthermore, aspects of the longitudinal course of the illness, like rapid cycling (RC), are reflected as well. Rapid cycling is defined as four or more affective episodes within one year of the illness. It has been postulated that rapid cycling is related with a poor response to lithium, to the same extent as mixed episodes or an atypical onset (depressive episode first) of the disease. Here, the current status of alternative pharmacological and supportive therapy of rapid cycling is presented and discussed. Furthermore, the article also displays biological parameters associated with rapid cycling like higher prevalence in women, hypothyreoidism, subtype of bipolar disorder, COMT-allele, influence of sleep or risk of antidepressant induced cycling.

Central pontine myelinolysis in a patient with anorexia nervosa.

UNLABELLED: Myelinolysis may occur as a severe complication of eating disorders, especially anorexia nervosa (AN). One of the most important reasons can be a rapid correction of hyponatremia caused by tubulopathy, water intoxication (WI), or abuse of diuretics in individuals with AN. METHOD AND RESULTS We report on a 24-year-old female patient with an 8-year history of AN. A rapid correction of severe hyponatremia and hypokalemia induced by WI led to central pontine myelinolysis, which was confirmed by magnetic resonance imaging (MRI) examination. Besides affective lability, incoherence, and an acute confusional state, surprisingly, no severe neurological symptoms emerged. CONCLUSION: Thus, physicians should be aware of the risk of pontine myelinolysis with new psychiatric symptoms emerging in the absence of obvious neurological deficits.

Antimanic efficacy of topiramate in 11 patients in an open trial with an on-off-on design.

BACKGROUND: A series of open studies suggests that topiramate has efficacy in bipolar disorder. To further investigate the potential value of topiramate as an antimanic agent, we conducted an open trial in 11 manic patients. METHOD: Eleven patients with bipolar I disorder with an acute manic episode (DSM-IV) were treated with a mood stabilizer and/or antipsychotics in sufficient and fixed doses. All had a Young Mania Rating Scale (YMRS) score of at least 24 (mean +/- SD = 33.5+/-8.1). Topiramate was added after stable plasma levels of concomitant mood stabilizers had been reached and was titrated within 1 week to a final dose in the range of 25 to 200 mg/day, depending on clinical efficacy and tolerability. Topiramate was discontinued after 10 days, while concomitant medication remained unchanged. After 5 days, topiramate was reintroduced at similar or increased dosages for another 7 days. Patients were assessed with the YMRS; the Clinical Global Impressions scale version for bipolar patients; and the 21-item Hamilton Rating Scale for Depression. RESULTS: Seven of the 11 patients initially showed a good antimanic response with > 50% reduction in YMRS score. One patient showed psychotic features following rapid increase in topiramate dosage and dropped out on day 10. After discontinuation of topiramate, 7 of the remaining 10 patients worsened (increase of > or = 25% in YMRS score), 2 remained stable, and 1 discontinued follow-up after good recovery. After reintroducing topiramate, all patients improved again within a week, with 8 of 9 meeting the responder criterion of > or = 50% YMRS score reduction when comparing baseline values with those of day 22. With the exception of the patient who developed psychosis, topiramate was well tolerated. Concomitant medication did not interfere with plasma levels of drug, except for carbamazepine level in 1 patient. CONCLUSION: The antimanic response among patients in this study appears reproducibly linked to the addition of topiramate.

[Effectiveness, safety and practicality of delayed-release minitablets of valproate in bipolar affective disorders]. / Wirksamkeit, Verträglichkeit und Praktikabilität von Valproat-Miniretardtabletten bei bipolaren affektiven Störungen.

UNLABELLED: Valproate has recently emerged as a drug of first choice in treating acute mania because of its efficacy and relative safety. It can be administered as an intravenous, oral non-sustained release or oral sustained release loading therapy. A new sustained release formulation of valproate consists of "mini-tablets" with the possible advantage of a less problematic and more reliable administration of the drug. We report on eleven patients with an acute manic exacerbation who were investigated for sufficient control of manic symptoms and the duration of building up and maintaining sufficient blood levels of valproate in once/d versus twice/d administration of valproate delayed release mini-tablets (VPA mrt.). Acute and prophylactic effectiveness in mania were rated with the Young-Mania Rating Scale (YMRS), respectively the Global Clinical Impression Scale for Bipolar Disorder (CGI-BP). RESULTS: Within a short period of time sufficient blood levels in both groups (once/d versus twice/d administration) were built up. Seven of eleven patients were responders according to a reduction of 50% of the YMRS. In respect of prophylactic treatment all of the ten patients showed satisfactory results and no re-exacerbation of manic symptoms or depression.

Psychopathological changes preceding motor symptoms in Huntington's disease: a report on four cases.

Neurodegenerative disorders often exhibit "classical" psychiatric symptoms as an initial presentation of the disease. Here we present four patients with different psychopathological abnormalities who were later diagnosed as having Huntington's disease. The range of symptoms covered affective and psychotic symptoms, antisocial behavior, cognitive problems reminiscent of dementia and suicidal idealisation. The pattern of progress of neuronal degeneration may be helpful in explaining the antecedent manifestation of psychiatric symptoms.

Improved auditory spatial tuning in blind humans.

Despite reports of improved auditory discrimination capabilities in blind humans and visually deprived animals, there is no general agreement as to the nature or pervasiveness of such compensatory sensory enhancements. Neuroimaging studies have pointed out differences in cerebral organization between blind and sighted humans, but the relationship between these altered cortical activation patterns and auditory sensory acuity remains unclear. Here we compare behavioural and electrophysiological indices of spatial tuning within central and peripheral auditory space in congenitally blind and normally sighted but blindfolded adults to test the hypothesis (raised by earlier studies of the effects of auditory deprivation on visual processing) that the effects of visual deprivation might be more pronounced for processing peripheral sounds. We find that blind participants displayed localization abilities that were superior to those of sighted controls, but only when attending to sounds in peripheral auditory space. Electrophysiological recordings obtained at the same time revealed sharper tuning of early spatial attention mechanisms in the blind subjects. Differences in the scalp distribution of brain electrical activity between the two groups suggest a compensatory reorganization of brain areas in the blind that may contribute to the improved spatial resolution for peripheral sound sources.

Alteration of digital representations in somatosensory cortex in focal hand dystonia.

Focal hand dystonia involves a loss of motor control of one or more digits; it is associated with the repetitive, synchronous movements of the digits made by musicians over periods of many years. Magnetic source imaging revealed that there is a smaller distance (fusion) between the representations of the digits in somatosensory cortex for the affected hand of dystonic musicians than for the hands of non-musician control subjects. The data suggest that use-dependent susceptibility to digital representation fusion in cortex may be involved in the etiology of focal dystonia. A successful therapy for the condition has been developed based on this consideration.