Never too little: Grip and lift forces following probabilistic weight cues in patients with writer's cramp.

Objective: Planning of voluntary object-related movements requires the estimation of the most probable object properties. We investigated how 14 writer's cramp (WC) patients compared to 14 controls use probabilistic weight cues in a serial grip-lift task.

Methods: In every grip-lift trial, an object of either light, medium or heavy weight had to be grasped and lifted after a visual cue gave a probabilistic prediction of the object weights (e.

The origin of the heartbeat and theories of muscle contraction. Physiological concepts and conflicts in the 19th century.

The origin of the incessant rhythmical heartbeat and the mechanism of muscle contraction have fascinated scientists over centuries. This short review outlines physiological explanations that were discussed in the 19th century starting with Albrecht von Haller (1708-1777), an 18th century physiologist who proposed that the heart has an intrinsic irritability. He argued that under normal conditions the inflow of blood stimulates the heart muscle to contract by mechanical touch and distension.

Cold and heavy: grasping the temperature-weight illusion.

The apparent heaviness of weights placed on the skin depends on their temperature. We studied the effects of such a temperature-weight illusion (TWI) on perception and action in 21 healthy volunteers. Cold (18 °C), thermal-neutral (32 °C, skin temperature) and warm (41 °C) test objects were placed onto the palm of the non-dominant hand.

Parkinsonian patients do not utilize probabilistic advance information in a grip-lift task.

Introduction: Patients with Parkinson's disease (PD) are known to have decision-making impairments in tasks involving probabilistic information. How PD patients utilize task-relevant probabilistic advance information to plan and initiate common motor tasks like grasping has not yet been studied.

Methods: PD patients (n = 15, OFF medication) and control participants repeatedly grasped and lifted an object, the weight of which could be light, medium, or heavy.

The Neurophysiology and Treatment of Motion Sickness.

Background: Seasickness and travel sickness are classic types of motion illness. Modern simulation systems and virtual reality representations can also induce comparable symptoms. Such manifestations can be alleviated or prevented by various measures.

Rediscovery of Otto Frank's contribution to science.

In the late 19th century, German physiologist Otto Frank (1865-1944) embarked on a near life-long research program of laying down the mathematical, methodological, and theoretical foundations in order to understand and define the performance of the heart and circulatory system in all their complexity. The existence of the "Frank-Starling law" testifies to this. Two of his seminal publications have been translated into English previously, introducing Frank's research on the dynamics of the heart and the arterial pulse to a wider audience.

Trunk muscle activation pattern in parkinsonian camptocormia as revealed with surface electromyography.

Introduction: Camptocormia is frequently seen in Parkinson's disease (PD) and multiple system atrophy. It is characterized by a pathological forward bending of the trunk during standing, often combined with a lateral trunk deviation. The etiology of camptocormia in PD is still unknown.

Mechanosensitivity: From Aristotle's sense of touch to cardiac mechano-electric coupling.

Scientific interest in mechanosensation likely commenced with Aristotle's description of the sense of touch in his treatise de Anima [On the Soul]. Considering touch as a vital sense distributed over the whole body, the philosopher outlined a "physiological concept" at the macro-level already 2400 years ago. From this starting point, we outline the onset of modern sensory physiology during the early 19th century.

Processing of probabilistic information in weight perception and motor prediction.

We studied the effects of probabilistic cues, i.e., of information of limited certainty, in the context of an action task (GL: grip-lift) and of a perceptual task (WP: weight perception).

Probabilistic information on object weight shapes force dynamics in a grip-lift task.

Advance information, such as object weight, size and texture, modifies predictive scaling of grip forces in a grip-lift task. Here, we examined the influence of probabilistic advance information about object weight. Fifteen healthy volunteers repeatedly grasped and lifted an object equipped with a force transducer between their thumb and index finger.

Weight-specific anticipatory coding of grip force in human dorsal premotor cortex.

The dorsal premotor cortex (PMd) uses prior sensory information for motor preparation. Here, we used a conditioning-and-map approach in 11 healthy male humans (mean age 27 years) to further clarify the role of PMd in anticipatory motor control. We transiently disrupted neuronal processing in PMd, using either continuous theta burst stimulation (cTBS) at 80% (inhibitory cTBS) or 30% (sham cTBS) of active motor threshold.

Activity of upper limb muscles during human walking.

The EMG activity of upper limb muscles during human gait has rarely been studied previously. It was examined in 20 normal volunteers in four conditions: walking on a treadmill (1) with unrestrained natural arm swing (Normal), (2) while volitionally holding the arms still (Held), (3) with the arms immobilized (Bound), and (4) with the arms swinging in phase with the ipsilateral legs, i.e.

Thermoreception and nociception of the skin: a classic paper of Bessou and Perl and analyses of thermal sensitivity during a student laboratory exercise.

About four decades ago, Perl and collaborators were the first ones who unambiguously identified specifically nociceptive neurons in the periphery. In their classic work, they recorded action potentials from single C-fibers of a cutaneous nerve in cats while applying carefully graded stimuli to the skin (Bessou P, Perl ER. Response of cutaneous sensory units with unmyelinated fibers to noxious stimuli.

Functional impact of the rhabdosphincter branch of the pelvic nerve on the membranous urethra in comparison to that of the pudendal nerve in male rabbits.

Introduction: The innervation of the membranous urethra (MU) is still under debate. We analysed the functional effects of electrostimulation of the rhabdosphincter branch of the pelvic nerve (RBP) on the MU in a standardized male rabbit model, paying attention both to the efferent and the possible afferent effects of stimulation.

Material And Methods: Six male rabbits (chinchilla bastards) were included in this study.

Cortical representation of the urge to void: a functional magnetic resonance imaging study.

Purpose: The urge to void generally increases with bladder distention but the relationship between the 2 factors is complex. When the bladder is moderately filled, the desire to void can be called forth deliberately but it can also be suppressed. To elucidate human brain mechanisms that are active during such intentional modulations of the desire to void we performed functional magnetic resonance imaging in healthy volunteers.

Grasping with the left and right hand: a kinematic study.

The goal of the present study was to compare prehension movements of the dominant and the non-dominant hand. Twenty right-handed volunteers (age 20-30 years) reached forward to grasp a cylindrical object, which was lifted and then placed into a target position in a retraction-insertion movement. The movements were performed at three different velocities (normal, deliberately fast, or slowly) both, under visual control, and in a no-vision condition.

Living a normal life with the nondominant hemisphere: magnetic resonance imaging findings and clinical outcome for a patient with left-hemispheric hydranencephaly.

In hemihydranencephaly, the human brain lacks 1 complete hemisphere. An occlusion of the carotid artery, affecting all supplied territories, is thought to be the underlying mechanism. This extremely rare disorder, of which only 7 cases have been reported to date, is thought to occur before the last trimester of gestation (20th to 27th week), after neural migration but before synaptogenesis.

Hand coordination following capsular stroke.

Motor outcome following stroke of the internal capsule is variable and its determinants are poorly understood. While many patients fully regain their abilities, recovery of motor functions remains incomplete in others. We analysed functional motor tasks of the upper limb to determine the pattern of focal disability after a small infarct of the internal capsule ('pure motor stroke') in the chronic stage (mean 2.

Recovery of the precision grip in children after traumatic brain injury.

Objective: To identify quantitative parameters that are sensitive enough to detect impairments and improvements of grasping in children after traumatic brain injury (TBI) by analyzing the isometric fingertip forces of a precision grip-lift task.

Design: Follow-up and case-control study.

Setting: Tertiary pediatric trauma rehabilitation center in Germany.

Sensorimotor recovery in children after traumatic brain injury: analyses of gait, gross motor, and fine motor skills.

The recovery of gait, gross motor proficiency, and hand function was examined in 23 children (13 males, 10 females; age 4 years 7 months to 15 years 10 months) with traumatic brain injury (TBI) over five months of in patient rehabilitation. We used gait analysis, the Gross Motor Function Measure, the Developmental Hand Function Test, and the Purdue Pegboard test. Brain injury had been severe (initial Glasgow Coma Scale GCS <8) in 17 children and moderate (GCS 8-10) in six children.

Subthalamic nucleus stimulation for Parkinson's disease preferentially improves akinesia of proximal arm movements compared to finger movements.

Deep brain stimulation of the subthalamic nucleus (STN-DBS) reduces akinesia in Parkinson's disease but its impact on fine motor functions was unknown. We assessed the effects of DBS and a levodopa (L-dopa) test on the timing of the precision grip in 18 patients. Improvement on UPDRS-items reflecting hand functions and the shortening of the first phases of the precision grip were more distinct in the L-dopa test than in the pure STN-DBS condition.

Assessment of sensorimotor functions after traumatic brain injury (TBI) in childhood - Methodological aspects.

Various basic qualitative and quantitative methods for the evaluation of sensorimotor functions after Traumatic Brain Injury (TBI) are introduced and discussed. Methodological aspects are illustrated by a single case follow-up study of a child after severe TBI (age 11; 7-12;1 yrs; 6, 8 and 12 month post TBI) in comparison to an age-matched healthy control group (N=16). The evaluation consisted of neurological investigation, Barthel-Index, Terver Numeric Score for Functional Assessment, Rappaport Disability Rating Scale (modified version), a coordination-test for children (KTK), a pilot-tested Motor Function Score, quantitative evaluation of spatiotemporal gait parameters on a walkway and on a treadmill, and the kinematic assessment of hand motor functions.

Analyses of gait, reaching, and grasping in children after traumatic brain injury.

Objective: To evaluate motor behavior in children after traumatic brain injury (TBI) with quantitative instrumented measures of gait and of functional hand movements (reaching, grasping) and with clinical assessments.

Design: Case-control study.

Setting: Tertiary pediatric trauma rehabilitation center in Germany.