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PubMed2001

Enriched rehabilitative training promotes improved forelimb motor function and enhanced dendritic growth after focal ischemic injury.

Chronic impairment of forelimb and digit movement is a common problem after stroke that is resistant to therapy. Previous studies have demonstrated that enrichment improves behavioral outcome after focal ischemia; however, postischemic enrichment alone is not capable of enhancing fine digit and forelimb function. Therefore, we combined environmental enrichment with daily skilled-reach training to assess the effect of intensive task-specific rehabilitation on long-term functional outcome. Rats were subjected to either endothelin-1-induced focal ischemia or sham surgery and subsequently designated to enriched-rehabilitation or standard-housing treatment groups starting 15 d after ischemia. Functional assessment of the affected forelimb at 4 and 9 weeks after treatment revealed that ischemic plus enrichment (IE) animals had improved approximately 30% on the staircase-reaching task and were indistinguishable from sham animals for both latency and foot faults in a beam-traversing task. In contrast, ischemic plus standard (IS) animals remained significantly impaired on both tasks. Interestingly, both ischemic groups (IE and IS) relied on the nonaffected forelimb during upright weight-bearing movements, a pattern that persisted for the duration of the experiment. Dendritic arborization of layer V pyramidal cells within the undamaged motor cortex was examined using a Golgi-Cox procedure. IE animals showed enhanced dendritic complexity and length compared with both IS and sham groups. These results suggest that enrichment combined with task-specific rehabilitative therapy is capable of augmenting intrinsic neuronal plasticity within noninjured, functionally connected brain regions, as well as promoting enhanced functional outcome.

Animals↗
PubMed1981

Effect of atropine on esophageal motor function in humans.

In this study, we used a high-fidelity manometric recording system to quantitate the effects of atropine on lower esophageal sphincter (LES) pressure and primary peristalsis (1 degree P). A sleeve sensor recorded LES pressure, and seven recording orifices spaced at 3-cm intervals registered motor activity in the esophageal body. Five randomized manometric studies were done in each of five normal subjects. LES pressure and 1 degree P with wet swallows were recorded for 30 min before and 70 min after intravenous injection of saline or atropine, 3, 6, 12, and 24 micrograms/kg. We also studied the effect of atropine on LES pressure in five additional subjects, four dogs, four opossums, and six monkeys. In humans, saline and 3 micrograms/kg atropine caused no significant change in pulse rate, LES pressure, or the incidence of complete peristaltic sequences. The 6, 12, and 24 micrograms/kg atropine doses caused significant inhibition of LES pressure and the incidence of intact 1 degree P. Only the 12 and 24 micrograms/kg doses increased pulse rate. When 1 degree P occurred in the smooth muscle portion of the esophagus its appearance in the proximal portion of the smooth muscle segment was delayed for several seconds. The amplitude of 1 degree P was decreased 30-60% in the smooth muscle segment, but 1 degree P was not affected in the proximal striated muscle esophageal segment. Atropine reduced canine LES pressure substantially but caused no change in opossums or monkeys. We conclude that 1) basal LES tone in humans and dogs, unlike that of the opossum and monkey, is partially generated by cholinergic neural input, 2) cholinergic nerves elicit 1 degree P in human esophageal smooth muscle, and 3) species variation exists in esophageal responses to atropine.

Animals↗
PubMed1988

[Effect of cholecystokinin-octapeptide on the motor function of the digestive tract of the plaice].

The influence of cholecystokinin-octapeptide on the bioelectrical features of gastro-intestinal motility in sea-water fish (plaice) was investigated in chronic experiments. I. v. or intracerebral application of the peptide led to inhibition of the stomach cardia motor activity, to intensification and sparsity of the tonic and peristaltic contractions of the stomach pyloric part, and to an increase in the intestine fore-part activity. Vagotomy prevented the effect of intracerebral application of cholecystokinin. Atropine prevented this effect of cholecystokinin irrespective of the mode of its application. Phentolamine or propranolol did not alter the effect.

Animals↗
PubMed1988

Motor functions of the striatum in the rat: critical role of the lateral region in tongue and forelimb reaching.

The findings of this study indicate a critical and selective role of the rat's lateral striatum in performance of tongue and forelimb reaching. To test the hypothesis of regional specificity of motor control in the striatum, the effects of bilateral, ibotenate-induced lesions of either the lateral or the medial regions of the striatum on reaching movements of the tongue and the forelimbs were examined. Lesions of the lateral striatum caused severe and chronic impairments of movement initiation, postural synergisms and amplitude of both tongue and forelimb reaches. In contrast, lesions of the medial striatum produced mild or no chronic alterations of these motor parameters. These findings support the hypothesis of a selective role of the lateral striatum in the initiation and execution of reaching movements.

Animals↗
PubMed1988

Cerebral organization of verbal and motor functions in left-handed and right-handed adults: effects of concurrent verbal tasks on unimanual tapping performance.

Two experiments were conducted to study the interference effects of different concurrent verbal tasks on unimanual single-finger tapping and unimanual sequential finger tapping. Experiment 1 involved 24 right-handed university students. In the dual-task conditions, right-handers showed a greater right-hand than left-hand performance reduction for single-finger tapping, and an equal right-hand and left-hand reduction for sequential tapping. Experiment 2 involved 60 left-handed university students, divided into four groups according to familial sinistrality and writing hand posture. In the dual-task conditions, left-handers showed a greater left-hand than right-hand performance reduction for single-finger tapping, and an equal left-hand and right-hand reduction for sequential finger tapping. A dichotic listening task revealed a left hemispheric dominance for auditory linguistic functioning in most of the left-handers. Familial sinistrality and hand posture, on the whole, did not influence tapping performances. However, these factors influenced the ear asymmetries on the dichotic listening task. It is speculated that, with single-finger tapping, interference only takes place beyond the point of language motor programming, that is to say, at the motor areas and the supplementary motor areas of the cortex.

Adolescent↗
PubMed1983

Hemispheric asymmetries in motor function: I. Left-hemisphere specialization for memory but not performance.

Patients with unilateral brain lesions of vascular origin were administered tests designed to determine if left-hemisphere specialization in manual-sequence tasks involves memory for these sequences, or performance of them, or both. Patients with left-sided lesions were worse than patients with right-sided lesions on two tasks requiring the recall of hand positions. Whereas patients with left-sided lesions showed a trend towards being worse on speeded performance of an already learned manual sequence, in both groups on this task there were a large number of failures to remember the sequence. When memory demands were better controlled by providing a model during the speeded performance task, there were no group differences. It is proposed that there is left-hemisphere specialization for memory but not performance of such motor tasks.

Brain↗
PubMed2004

Recovery of gait and other motor functions after stroke: novel physical and pharmacological treatment strategies.

The gait-lab at Klinik Berlin developed and evaluated novel physical and pharmacological strategies promoting the repetitive practise of hemiparetic gait in line with the slogan: who wants to relearn walking, has to walk. Areas of research are treadmill training with partial body weight support, enabling wheelchair-bound subjects to repetitively practice gait, the electromechanical gait trainer GT I reducing the effort on the therapists as compared to the manually assisted locomotor therapy, and the future HapticWalker which will allow the additional practise of stair climbing up and down and of perturbations. Further means to promote gait practice after stroke was the application of botulinum toxin A for the treatment of lower limb spasticity and the early use of walking aids. New areas of research are also the study of D-Amphetamine, which failed to promote motor recovery in acute stroke patients as compared to placebo, and the development of a computerized arm trainer, Bi-Manu-T rack, for the bilateral treatment of patients with a severe upper limb paresis.

Botulinum Toxins, Type A↗
PubMed1989

Aminergic and peptidergic modulation of motor function at an identified neuromuscular junction in Helisoma.

Electrophysiological studies suggest that motoneurone B19 in the buccal ganglia of Helisoma makes monosynaptic, cholinergic connections with the supralateral radular tensor (SLT) muscle of the buccal mass. Serotonin (5-HT) and small cardioactive peptide B (SCPB) were found to have peripheral modulatory effects on this motor pathway that are consistent with their previously described central facilitatory effects. Both neurotransmitters, when applied exogenously (10(-6) mol l-1) to isolated buccal ganglion-buccal muscle preparations, potentiated the magnitude of motoneurone B19-evoked muscle contractions (6.3 and 2.7 times, respectively) without affecting excitatory junctional potential (EJP) amplitudes. When applied to single dissociated SLT muscle fibres in cell culture, these modulators had similar effects on acetylcholine (ACh)-evoked muscle fibre shortening, demonstrating that these neuromodulators exert direct actions on the muscle cells. The cardioactive peptide FMRFamide (10(-6) mol l-1), although slightly potentiating muscle contractions in reduced neuromuscular preparations, significantly decreased both ACh-evoked muscle fibre shortening and depolarizing potentials in cultured SLT muscle cells. The differential effects of FMRFamide may, in part, be due to the elimination of interactive effects between multiple neurotransmitters that might exist in semi-intact preparations and in vivo. These results demonstrate that 5-HT, SCPB and FMRFamide in Helisoma can directly modulate the peripheral muscle targets of buccal motoneurones involved in the generation of cyclical feeding behaviour.

Acetylcholine↗
PubMed2003

Dynamic reconstruction of large abdominal defects using a free rectus femoris musculocutaneous flap with normal motor function.

Reconstruction of large abdominal wall defects with conventional reconstruction including the component separation technique is difficult because of strong transverse tension and loss or weakness of the rectus abdominis muscle. To overcome this problem, dynamic reconstruction of the abdominal wall using a free innervated rectus femoris musculocutaneous flap was performed for large defects with separation of the bilateral rectus abdominis muscles. The intact motor nerve of the rectus femoris muscle was transferred without transection, and only the pedicle vessels were anastomosed to the omental vessels. Four and one-half years after surgery, the rectus femoris muscle had voluntary strong muscle contraction and there was no abdominal protrusion, herniation, or donor morbidity. This new method with dynamic function can replace conventional techniques for large abdominal defects without rectus muscle function.

Abdominal Wall↗
PubMed2006

Impaired motor function in mice with cell-specific knockout of sodium channel Scn8a (NaV1.6) in cerebellar purkinje neurons and granule cells.

The Scn8a gene encodes the voltage-gated Na channel alpha subunit Na(V)1.6, which is widely expressed throughout the nervous system. Global null mutations that eliminate Scn8a in all cells result in severe motor dysfunction and premature death, precluding analysis of the physiological role of Na(V)1.6 in different neuronal types. To test the effect of cerebellar Na(V)1.6 on motor coordination in mice, we used the Cre-lox system to eliminate Scn8a expression exclusively in Purkinje neurons (Purkinje KO) and/or granule neurons (granule KO). Whereas granule KO mice had only minor behavioral defects, adult Purkinje KO mice exhibited ataxia, tremor, and impaired coordination. These disorders were exacerbated in double mutants lacking Scn8a in both Purkinje and granule cells (double KO). In Purkinje cells isolated from adult Purkinje KO and double KO but not granule KO mice, the ratio of resurgent-to-transient tetrodotoxin- (TTX)-sensitive Na current amplitudes decreased from approximately 15 to approximately 5%. In cerebellar slices, Purkinje cell spontaneous and maximal firing rates were reduced 10-fold and twofold relative to control in Purkinje KO and double KO but not granule KO mice. Additionally, short-term plasticity of high-frequency parallel fiber EPSCs was altered relative to control in Purkinje KO and double KO but not granule KO mice. These data suggest that the specialized kinetics of Purkinje Na channels depend directly on Scn8a expression. The loss of these channels leads to a decrease in Purkinje cell firing rates as well as a modification of the synaptic properties of afferent parallel fibers, with the ultimate consequence of disrupting motor behavior.

Action Potentials↗