Functional organisation of the facial motor system in man

To investigate human corticobulbar projections, electromyographic responses from orbicularis oculi and orbicularis oris muscles were recorded in 11 healthy subjects after transcranial magnetic stimulation. Selective activation of lower facial motoneurones of one hemisphere was reached with the round coil 4 cm lateral to the vertex on a line to the external auditory meatus with stimulus intensities from 45 to 55% (100% = 1.5 T). The mean latency of the OR muscle was 11.5 +/- 1.77 ms contralaterally. Ipsilateral cortical responses were observed in 5 subjects (45%) at a mean latency of 13.88 +/- 2.17 ms. Corticobulbar innervation may have affected bilateral responses in the lower facial muscles as those persisted even after lidocaine blockade of both supraorbital nerves. The functional importance of ipsilateral projections to the lower facial muscles in man is lower than that of the contralateral projections, as evidenced by the fact that they cannot be observed in all subjects or in all motor units. The influence of the trigeminal sensory afferents was excluded from the study after blockade of both supraorbital nerves.     

Motor consequences of motor area ablations in man

Motor disorders reported in the present paper do not result from cortical ablations stricto sensu since some white matter was excised in every patient. However they appear to suggest that, as suggested by Walshe (1935), the central region and premotor area are a functional entity, i.e. they work as a whole. The extensive lesions of the premotor area, leaving untouched the motor region, have the same motor and tonic consequences as lesions limited to the central region. This point which appears specific for man does not imply that the premotor region subserves activities similar to those subserved by the central region. Rather it may suggest a deafferentiation of the central region, the consequences of which would be more important than is generally assumed. Extensive central or premotor lesions determine various tonic disorders: a well known spasticity, with exaggeration of the stretch reflex, associated with an increase in passive swinging of segments of limbs and in extensibility of joints. These two latter phenomena are usually defined as hypotonia. With premotor and precentral lesions the hypotonia disappears and a hemiplegic posture is observed. This hemiplegic posture is a dystonia which apparently does not result directly from the exaggeration of the stretch reflex. Anatomically it appears to result from lesions of both central and premotor regions. This is in agreement with Denny-Brown's (1966) contention that an extrapyramidal region lies rostral to the prerolandic sulcus. As suggested by Evarts (1973) motor regions appear to control automatic as well as voluntary movements. They probably play a role in the trophic function of muscle, since, despite rehabilitation, amyotrophy was present in every case reported in the present paper.     

Relationship of rhythm discrimination to motor rhythm performance.

"Scores on the Seashore tests of time and rhythm discrimination were correlated with performance scores on eight rhythms, each of which were presented at three rates for a total of 24 trials. The above measures were also correlated with the performance of equal short time intervals. Positive and significant correlations between the discrimination and performance tests were obtained, confirming earlier results of R. H. Seashore. Rhythm discrimination scores correlated in all cases higher with rhythm performance than did the time discrimination scores. Rhythm discrimination also correlated as well as or better than did time discrimination with the performance of equal intervals. The need for inclusion of the Seashore time test as one of the musical measures was not confirmed here." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gender differences across age in motor performance: A meta-analysis.

Conducted a meta-analysis of 64 studies that reported gender differences on motor performance during childhood and adolescence. Findings yielded 702 effect sizes based on data from 15,518 female and 15,926 male 3–20 yr olds. Age was regressed on effect size, and the relation was significant for 12 of 20 tasks (e.g., balance, catching, grip strength, shuttle run, throw velocity, tapping). Several types of age-related curves were found; the curve for a throwing task was the most distinctive. Five of the tasks followed a typical curve of gender differences across age. For 8 tasks, gender differences were not related to age, and effect sizes were small. Results are discussed in relation to the development of gender differences to biological and environmental sources. A bibliography of the 64 studies is appended. (47 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of buccal motor programs elicited by a cholinergic agonist applied to the cerebral ganglion of Aplysia californica

Applying the non-hydrolyzable cholinergic agonist carbachol (CCh) to the cerebral ganglion of Aplysia elicits sustained, regular bursts of activity in the buccal ganglia resembling those seen during biting. The threshold for bursting is approximately 10(-4) M. Bursting begins after a 2 to 5 min delay. The burst frequency increases over the first 5 bursts, reaching a plateau value of approximately 3 per minute. Bursting is maintained for over 10 min. Some of the effects of CCh may be attributed to its ability to depolarize and fire CBI-2, a command-like neuron in the cerebral ganglion that initiates biting. CBI-2 is also depolarized by ACh, and by stimulating peripheral sensory nerves. Excitation of CBI-2 caused by carbachol is partially blocked by the muscarinic antagonist atropine. We examined whether CCh-induced bursting is modified in ganglia taken from Aplysia that previously experienced treatments inhibiting feeding, such as satiation, head shock contingent or non-contingent with food, and training animals with an inedible food. No treatment consistently and repeatedly affected the latency, the peak burst period, the length of time that bursting was maintained, or the threshold CCh concentration for eliciting bursting. However, there was a decrease in the rate of the build-up of the buccal ganglion program in previously satiated animals.     

A demonstration of generalization of performance across settings, materials, and motor responses for students with profound mental retardation

A treatment package, consisting of multiple exemplar training and community-based instruction, was evaluated for its effectiveness in teaching four students with profound mental retardation and multiple disabilities to participate in two sets of community-living tasks. All training took place in community settings, and each student demonstrated improved performance on at least one task set. In addition, all students demonstrated improved performance on a series of tasks selected to assess generalization of performance across settings, materials, and/or motoric responses required to complete the target task. Maintenance of performance over a 4- to 5-month period was assessed and achieved for two of the students. The results of this investigation are discussed in terms of the implications for programming for students with profound mental retardation.     

Age, experience, and performance on speed and skill jobs in an applied setting.

The decremental theory of aging (e.g., A. T. Welford, 1965), which is based on extensive laboratory investigations, maintains that abilities decline as workers age. In the present study, the theory was applied to an examination of the relation of age and experience to productivity, absenteeism, accidents, and turnover among 667 garment workers. Ss were separated into 6 age categories that formed the basis of a cross-sectional design. A crucial distinction was drawn between jobs requiring speed and those demanding skill. It was hypothesized that physical decrements would be more relevant to performance on speed jobs than on skill jobs, but contrary to predictions, older Ss surpassed the younger ones in both job categories. Partial correlations between experience and performance, which removed the influence of age, demonstrated that experience rather than age determined performance. However, the present design did not allow assessment of self-selection biases that may distinguish Ss who kept on working from those who terminated. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transdermal absorption of clindamycin and tretinoin from topically applied anti-acne formulations in man

The percutaneous absorption of clindamycin was studied in healthy male volunteers, comparing two investigative clindamycin (% w/v)/tretinoin (0.025% w/v) gels, containing clindamycin phosphate ester and clindamycin HCl, respectively, relative to a clindamycin phosphate lotion (1% clindamycin; Dalacin T). Formulations were applied daily for 5 days on the face, according to a balanced complete block design. Redness of the skin was scored visually, and blood and urine were collected. Clindamycin plasma levels did not exceed the limit of quantification (5 ng mL(-1)) with the clindamycin phosphate formulations, but one volunteer who received the clindamycin HCl/tretinoin gel showed plasma levels of up to 13 ng mL(-1). Clindamycin urinary excretion for 12 h after application of the clindamycin phosphate/tretinoin gel was comparable to the values of the reference lotion, whereas the clindamycin HCl/tretinoin gel gave significantly higher values. Erythema appeared to be associated with increased urinary excretion. The formulations were tolerated well. In a separate clinical pilot study in acne patients, the transdermal uptake of tretinoin and clindamycin from the clindamycin phosphate/tretinoin gel was monitored. Plasma samples were collected after 4 and 12 weeks of daily treatment. None of the study plasma samples contained measurable tretinoin levels. Clindamycin levels were not quantifiable in the majority (87%) of samples, the highest plasma level was 11 ng mL(-1). The chemical form of clindamycin proved to modulate skin irritation and percutaneous uptake of clindamycin from a gel formulation in healthy subjects. There was no indications for a notable transdermal uptake of tretinoin during daily application of the gel in patients, nor for an enhancing effect of tretinoin on clindamycin uptake.     

Limited conscious monitoring of motor performance in normal subjects

Normal subjects traced sagittal lines on a graphic tablet using a stylus held in their right hand. The hand was hidden by a mirror in which they saw the lines projected from a computer screen. In normal trials, the line seen in the mirror exactly corresponded to the traced line. In perturbed trials, a bias was introduced by the computer, so that the line appeared to deviate in one direction (right or left) by a variable angle (2, 5, 7 or 10 degrees). Subjects consistently displaced their hand in the opposite direction for producing a visually sagittal line. After each trial, they were asked in which direction they thought their hand had moved. In perturbed trials, they grossly underestimated the hand deviation. In addition, a post-hoc analysis revealed that one group of subjects misperceived the direction of their hand movement in the direction opposite to the perturbation (Group 1, including 9 Ss), whereas the other group gave responses in the correct direction (Group 2, including 4 Ss). In a second session using the same experimental paradigm, a motor response was asked for: subjects had to indicate the perceived direction of their hand during each trial by drawing a line with their eyes closed. Again, responses indicated a poor conscious monitoring of motor performance. These results suggest that normal subjects are not aware of signals generated by their own movements.     

Tongue, jaw, and lip muscle activity and jaw movement during experimental chewing efforts in man

The electromyographic (EMG) activity of the human genioglossus (GG) muscle during chewing efforts is not fully understood. In this study, the EMG activity of the human GG muscle during unilateral gum chewing was illustrated and correlated with the activities in the anterior temporalis (AT), the anterior digastric (DG), and the inferior orbicularis oris (OI) muscles. GG muscle activity was measured with customized surface electrodes, while other muscles were recorded with conventional surface electrodes. EMG activities during tongue displacement and the articulation of long vowels, recorded by the customized electrodes, were consistent with the recordings obtained by fine wire electrodes placed in the GG muscle. Jaw displacement was monitored by means of a kinesiograph with a transducer attached to the mandibular central incisors. Mean normalized GG muscle activity showed an onset in the last one-fifth of the intercuspal phase, gradually increasing during jaw-opening, and at its greatest immediately before the maximum jaw-opening position. It then decreased during jaw-closing and ceased in intercuspation but showed a small rebound in the third fifth of the intercuspal phase. The GG muscle burst showed phase lags with the DG and OI muscles and an opposite phase with the AT muscle (all P < 0.0001). All correlations were statistically significant (all P < 0.0001, r values between 0.88 and 0.97). The results suggest central coordination of the timing of the activities of the jaw, lip, and tongue muscles in chewing.     

Prenatal exposure to alcohol, caffeine, tobacco, and aspirin: Effects on fine and gross motor performance in 4-year-old children.

Fine and gross motor performance in 4-year-old children was examined in relation to prenatal exposure to alcohol, caffeine, tobacco, and aspirin in a longitudinal prospective population-based study. Multiple regression analyses of data from 449 children indicated statistically significant relationships between moderate levels of prenatal alcohol exposure and increased errors, increased latency, and increased total time on the Wisconsin Fine Motor Steadiness Battery and poorer balance on the Gross Motor Scale, even after adjustment for relevant covariates. Most of these alcohol-related motor findings were linear, suggesting no safe level of exposure. Alcohol scores from the period prior to pregnancy recognition were the most predictive of decrements in motor performance. Although moderate prenatal alcohol exposure was also related to lower IQ scores in this same cohort, the motor effects were independent of IQ. Some relationships with aspirin and caffeine were also found, but they were difficult to interpret. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Locally applied antisense oligonucleotide to proliferating cell nuclear antigen inhibits intimal thickening in experimental vein grafts

This study examines the effect of antisense oligonucleotide to proliferating cell nuclear antigen (PCNA) on the formation of vein graft intimal hyperplasia in vivo, using localized administration. Twenty-four New Zealand white rabbits had a right carotid interposition bypass graft using the external jugular vein and were sacrificed on the 28th postoperative day. To determine the effect of PCNA on the development of intimal hyperplasia, 6 animals had their grafts coated with a pluronic gel containing 18 base antisense oligonucleotide to PCNA (1 mg/ml), 6 received a pluronic gel containing an 18 base nonsense oligonucleotide (1 mg/ml), and 12 animals were controls (6 with and 6 without pluronic gel). These grafts were harvested for morphology and videomorphometry. There was no change in the intimal thickness between the control and gel-treated groups. (70 +/- 4 microm versus 72 +/- 4 microm; mean +/- s.e.m.; p = ns). The presence of nonsense oligonucleotide had no further effect. Antisense PCNA produced a 26% decrease in intimal thickness to 50 +/- 4 microm in the treated vein grafts (p < 0.03) without a change in medial thickness. This study shows that a local single application of antisense oligonucleotide to PCNA will reduce the intimal hyperplasia in experimental vein grafts over 28 days.     

Evidence that trigeminal brainstem interneurons form subpopulations to produce different forms of mastication in the rabbit

To determine how trigeminal brainstem interneurons pattern different forms of rhythmical jaw movements, four types of motor patterns were induced by electrical stimulation within the cortical masticatory areas of rabbits. After these were recorded, animals were paralyzed and fictive motor output was recorded with an extracellular microelectrode in the trigeminal motor nucleus. A second electrode was used to record from interneurons within the lateral part of the parvocellular reticular formation (Rpc-alpha, n = 28) and gamma- subnucleus of the oral nucleus of the spinal trigeminal tract (NVspo-gamma, n = 68). Both of these areas contain many interneurons projecting to the trigeminal motor nucleus. The basic characteristics of the four movement types evoked before paralysis were similar to those seen after the neuromuscular blockade, although cycle duration was significantly decreased for all patterns. Interneurons showed three types of firing pattern: 54% were inactive, 42% were rhythmically active, and 4% had a tonic firing pattern. Neurons within the first two categories were intermingled in Rpc-alpha and NVspo-gamma: 48% of rhythmic neurons were active during one movement type, 35% were active during two, and 13% were active during three or four patterns. Most units fired during either the middle of the masseter burst or interburst phases during fictive movements evoked from the left caudal cortex. In contrast, there were no tendencies toward a preferred coupling of interneuron activity to any particular phase of the cycle during stimulation of other cortical sites. It was concluded that the premotoneurons that form the final commands to trigeminal motoneurons are organized into subpopulations according to movement pattern.     

Modulation of ipsilateral motor cortex in man during unimanual finger movements of different complexities

Amiodarone is an antiarrhythmic drug widely used to treat a variety of supraventricular and ventricular arrhythmias. However its drawback is a very slow elimination and very frequent adverse effects (thyroid, pulmonary, neurologic, ocular, dermatologic, hepatic disorders). We describe a patient who developed a pseudoalcoholic liver disease and a cirrhosis after use of Amiodarone for a long period of time.     

The interaction of ethanol and delta9-tetrahydrocannabinol in man: effects on perceptual, cognitive and motor functions

Twelve paid student volunteers (8 male, 4 female) were used in a double-blind crossover experiment to investigate the effects of delta9-tetrahydrocannabinol (THC) alone, and in combination with ethanol, on human perceptual, cognitive and motor functions. Both THC (10 mg/70 kg) and ethanol (0-5 g/kg) had little effect when administered alone. The combination of drugs, however, induced a significnat decrement in performance in some of the tests and this interaction was considered to be at least additive. The peak blood ethanol concentration was higher (P = 0-05) when subjects received both ethanol and THC than when they received ethanol alone.