The volition, the mode of movement selection and the readiness potential.

A growing body of evidence suggests that the mode of movement selection is relevant for the readiness potential, namely, internal (or free) selection of movements is associated with increased readiness potential amplitudes compared to predetermined or externally guided selection. It is little acknowledged, however, that this finding may be ascribed to the different expression of volition (i.e.

Age and Disease have a Distinct Influence on Postural Balance of Patients with COPD.

The postural imbalance is an extra-pulmonary condition, associated with chronic obstructive pulmonary disease (COPD). COPD affects older individuals and it is unclear whether balance abnormalities can be described as pathophysiological mechanism or aging. The present study aimed to evaluate the influence of age or disease on postural balance of patients with COPD.

Disruption of volitional control in obsessive-compulsive disorder: Evidence from the Bereitschaftspotential.

In the context of controversies involving possible abnormalities in the volition and action control in obsessive-compulsive disorder (OCD), the current study examined electroencephalographic correlates of automatic and volitional brain processes involved in the genesis of spontaneous movements in individuals diagnosed with OCD. For this, the amplitudes of early and late Bereitschaftspotential (early BP and late BP) from 12 patients and 12 controls were obtained while they performed spontaneous button presses under different levels of volitional experience. In the first condition, participants were distracted from their motor actions by a mental task (automatic condition) and in the second condition they were instructed to attending to their own intention to move (willed condition).

Young and older adults adapt automatic postural responses equivalently to repetitive perturbations but are unable to use predictive cueing to optimize recovery of balance stability.

Processing of contextual cues has been proposed to modulate the generation of automatic postural responses to unanticipated balance perturbations. In this investigation, we compared young and older individuals in responses to sudden rotations of the support base inducing either planti- or dorsiflexion of the ankles. Assessment was made in conditions resulting from the combination of visual directional cueing of the forthcoming platform rotation, and block versus random sequences of platform rotation directions.

The effect of conscious intention to act on the Bereitschaftspotential.

The current study investigated the effect of conscious intention to act on the Bereitschaftspotential. Situations in which the awareness of acting is minimally expressed were generated by asking 16 participants to press a button after performing a mental imagery task based on animal pictures (automatic condition). The affective responses induced by the pictures were controlled by selecting the animals according to different valences, threatening and neutral.

Obsessive-Compulsive Disorder.

Purpose Of Review: This article reviews current knowledge regarding diagnosis, pathophysiology, and treatment trends in obsessive-compulsive disorder (OCD), a severe, underrecognized, and chronic condition frequently encountered in neurologic practice.

Recent Findings: With a lifetime prevalence estimated at 2.5%, OCD is a common condition that can also present comorbidly with neurologic disease.

Development of postural control and maturation of sensory systems in children of different ages a cross-sectional study.

Objective: To evaluate the stability, postural adjustments and contributions of sensory information for postural control in children.

Methods: 40 boys and 40 girls were equally divided into groups of 5, 7, 9 and 12 years (G5, G7, G9 and G12). All children were submitted to dynamic posturography using a modified sensory organization test, using four sensory conditions: combining stable or sway referencing platform with eyes opened, or closed.

Comparative analysis of the electroencephalogram in patients with Alzheimer's disease, diffuse axonal injury patients and healthy controls using LORETA analysis.

Unlabelled: Alzheimer's disease (AD) is a dementia that affects a large contingent of the elderly population characterized by the presence of neurofibrillary tangles and senile plaques. Traumatic brain injury (TBI) is a non-degenerative injury caused by an external mechanical force. One of the main causes of TBI is diffuse axonal injury (DAI), promoted by acceleration-deceleration mechanisms.

Individual topographic variability is inherent to cortical physiology but task-related differences may be noise.

The observation of highly variable sets of association neocortical areas across individuals, containing the estimated generators of Slow Potentials (SPs) and beta oscillations, lead to the persistence in individual analyses. This brought to notice an unexpected within individual topographic similarity between task conditions, despite our original interest in task-related differences. A recent related work explored the quantification of the similarity in beta topography between largely differing tasks.

Precueing time but not direction of postural perturbation induces early muscular activation: comparison between young and elderly individuals.

In this study, we evaluated the effect of precueing characteristics of an impending perturbation to upright stance on reactive responses of distal leg muscles. Young and older individuals were compared in a task of recovering stable upright stance following rotation of the supporting platform to induce anterior or posterior body sway. Directions of the supporting platform rotation were randomized across trials.

The concepts of representation and information in explanatory theories of human behavior.

Focusing in experimental study of human behavior, this article discusses the concepts of information and mental representation aiming the integration of their biological, computational, and semantic aspects. Assuming that the objective of any communication process is ultimately to modify the receiver's state, the term correlational information is proposed as a measure of how changes occurring in external world correlate with changes occurring inside an individual. Mental representations are conceptualized as a special case of information processing in which correlational information is received, recorded, but also modified by a complex emergent process of associating new elements.

Lack of systematic topographic difference between attention and reasoning beta correlates.

Based on previous evidence for individual-specific sets of cortical areas active during simple attention tasks, in this work we intended to perform within individual comparisons of task-induced beta oscillations between visual attention and a reasoning task. Since beta induced oscillations are not time-locked to task events and were first observed by Fourier transforms, in order to analyze the cortical topography of attention induced beta activity, we have previously computed corrected-latency averages based on spontaneous peaks of band-pass filtered epochs. We then used Independent Component Analysis (ICA) only to single out the significant portion of averaged data, above noise levels.

Space and motion perception and discomfort in air travel.

Introduction: The perception of comfort during air trips is determined by several factors. External factors like cabin design and environmental parameters (temperature, humidity, air pressure, noise, and vibration) interact with individual characteristics (anxiety traits, fear of flying, and personality) from arrival at the airport to landing at the destination. In this study, we investigated the influence of space and motion discomfort (SMD), fear of heights, and anxiety on comfort perception during all phases of air travel.

Balance disturbances in asthmatic patients.

Objective: The aim of this study was to investigate balance control in asthmatic patients.

Methods: Thirty subjects with controlled persistent asthma were compared with 30 non-asthmatic subjects who were matched by age and sex. Individuals who had received psychiatric treatment, demonstrated chronic musculoskeletal pain, had limited joint movements, or showed vestibular or other equilibrium disorders were excluded from both the groups to avoid biomechanical bias in the dynamic posturography.

Minor and unsystematic cortical topographic changes of attention correlates between modalities.

In this study we analyzed the topography of induced cortical oscillations in 20 healthy individuals performing simple attention tasks. We were interested in qualitatively replicating our recent findings on the localization of attention-induced beta bands during a visual task [1], and verifying whether significant topographic changes would follow the change of attention to the auditory modality. We computed corrected latency averaging of each induced frequency bands, and modeled their generators by current density reconstruction with Lp-norm minimization.

Fear of heights: cognitive performance and postural control.

Introduction: Fear of heights, or acrophobia, is one of the most frequent subtypes of specific phobia frequently associated to depression and other anxiety disorders. Previous evidence suggests a correlation between acrophobia and abnormalities in balance control, particularly involving the use of visual information to keep postural stability. This study investigates the hypotheses that (1) abnormalities in balance control are more frequent in individuals with acrophobia even when not exposed to heights, that (2) acrophobic symptoms are associated to abnormalities in visual perception of movement; and that (3) individuals with acrophobia are more sensitive to balance-cognition interactions.

Interindividual variability in EEG correlates of attention and limits of functional mapping.

In this study, we analyzed the EEG oscillatory activity induced during a simple visual task, in search of spectral correlate(s) of attention. This task has been previously analyzed by conventional event-related potential (ERP) computation, and Slow Potentials (SPs) were seen to be highly variable across subjects in topography and generators [Basile LF, Brunetti EP, Pereira JF Jr, Ballester G, Amaro E Jr, Anghinah R, Ribeiro P, Piedade R, Gattaz WF. (2006) Complex slow potential generators in a simplified attention paradigm.

Antidepressants and dizziness.

Despite several evidences supporting a close relationship between dizziness and anxiety symptoms, the role of antidepressants in the treatment of such conditions remains poorly explored. The high prevalence of dizziness during serotonin reuptake inhibitors discontinuation syndrome and the few reports suggesting efficacy of antidepressants in treating some vestibular disorders justify a careful investigation. Neurophysiologic studies suggest possible focus of investigation on mechanisms of drug action.

Reduced NAA levels in the dorsolateral prefrontal cortex of young bipolar patients.

Objective: Converging evidence implicates prefrontal circuits in the pathophysiology of bipolar disorder. Proton spectroscopy studies performed in adult bipolar patients assessing prefrontal regions have suggested decreased levels of N-acetylaspartate (NAA), a putative marker of neuronal integrity. In order to examine whether such abnormalities would also be found in younger patients, a 1H spectroscopy study was conducted that focused on the dorsolateral prefrontal cortex of children and adolescents with bipolar disorder.

Panic disorder patients have reduced cyclic AMP in platelets.

Little is known about the intracellular mechanisms involved in the pathophysiology of panic disorder (PD). Abnormalities in the cyclic AMP system have been described in several psychiatric disorders but there are no studies in panic patients. We evaluated not only the levels of platelet cyclic AMP, but also cyclic GMP and nitric oxide synthase (NOS) activity in patients with PD at baseline and after treatment with clomipramine and in healthy volunteers.