Temporally irregular mnemonic persistent activity in prefrontal neurons of monkeys during a delayed response task

An important question in neuroscience is whether and how temporal patterns and fluctuations in neuronal spike trains contribute to information processing in the cortex. We have addressed this issue in the memory-related circuits of the prefrontal cortex by analyzing spike trains from a database of 229 neurons recorded in the dorsolateral prefrontal cortex of 4 macaque monkeys during the performance of an oculomotor delayed-response task. For each task epoch, we have estimated their power spectrum together with interspike interval histograms and autocorrelograms. We find that 1). the properties of most (about 60%) neurons approximated the characteristics of a Poisson process. For about 25% of cells, with characteristics typical of interneurons, the power spectrum showed a trough at low frequencies (<20 Hz) and the autocorrelogram a dip near zero time lag. About 15% of neurons had a peak at <20 Hz in the power spectrum, associated with the burstiness of the spike train; 2). a small but significant task dependency of spike-train temporal structure: delay responses to preferred locations were characterized not only by elevated firing, but also by suppressed power at low (<20 Hz) frequencies; and 3). the variability of interspike intervals is typically higher during the mnemonic delay period than during the fixation period, regardless of the remembered cue. The high irregularity of neural persistent activity during the delay period is likely to be a characteristic signature of recurrent prefrontal network dynamics underlying working memory.     

Early onset of action and efficacy of a combination of calcipotriene and betamethasone dipropionate in the treatment of psoriasis

BACKGROUND: Calcipotriene and betamethasone dipropionate are topical treatments for psoriasis vulgaris. Their mode of action is different. Improved risk/benefit may result with concomitant use of the two compounds together. A new vehicle has been created with the objective of obtaining optimal stability of both calcipotriene and betamethasone dipropionate in the combination product. OBJECTIVE: We compared the clinical efficacy of a fixed combination of calcipotriene and betamethasone dipropionate in a new vehicle to calcipotriene in the new vehicle, betamethasone in the new vehicle, and the new vehicle alone. METHODS: This was an international, multicenter, prospective, randomized, double-blind, parallel-group, 4-week study in patients with psoriasis vulgaris amenable to topical treatment. RESULTS: The mean percentage reduction in PASI from baseline to end of treatment was 73.2% in the combination group (n = 301), 48.8% in the calcipotriene group (n = 308), 63.1% in the betamethasone dipropionate group (n = 312) and 28.8% in the new vehicle group (n = 107), (P < .001). The mean percentage reduction in PASI during the first week was 48.1%, 28.4%, 41.4%, and 21.5%, respectively (P < .001). CONCLUSION: A combination product of calcipotriene 50 microg/g and betamethasone dipropionate 0.5 mg/g in the new vehicle shows superior efficacy with a more rapid onset of action than the new vehicle containing either constituent alone in the treatment of psoriasis vulgaris.     

Function testing in patients with old rupture of the anterior cruciate ligament

Fifteen patients with isolated old rupture of the anterior cruciate ligament (ACL) were examined to judge their functional disability. The following basic factors were used for evaluation: thigh muscle strength testing, stabilometry in a one-leg stance with straight and flexed knee, gait analysis, performance tests, knee function score, activity grading scale, and clinical joint laxity tests. We found that these rehabilitated patients mainly had impaired performance in those tests which greatly stressed the knee joint's sagittal stability. One-leg hop length was impaired for the injured limb. This group of patients had bilateral impairment of postural control compared with a reference group. This dysfunction was not revealed when comparing limbs. A derotation brace (ECKO) had neither a positive nor a negative effect in the tests. Different aspects of knee function evaluation are emphasized. Some of the altered functions are suggested to be due to central adjustments of motor control.     

Ice hockey injuries: incidence, nature and causes.

In this prospective study, we have investigated incidence of injuries of different severity, types of injury, and mechanisms of injury during ice hockey games. All twelve Swedish elite hockey teams were observed during the season 1988-1989 when a total number of 664 games were played. There was a total number of 285 injuries, of which the majority were minor (61%) and only 9% were classified as major. Seventy-four per cent of the injuries occurred during games and 26% during practice. The overall incidence of injury was 53.0 per 1000 player-game hours. Eighty-five per cent of injuries were caused by trauma and 15% by over-use. Injuries were most often localized to the head/face (39%) or the lower limb (32%). Most injuries resulted from stick contact or player contact including checking. A reduction of minor and moderate injuries should be possible by stricter enforcement of the hockey rules, and more widespread use of visors.     

The effect of derotation braces on knee motion

Four different types of derotation braces and an elastic knee support were tested on ice-hockey players. The elastic support did not noticeably affect rotation and abduction-adduction of the knee. All four braces reduced rotation and abduction-adduction in test actions simulating sports situations. Flexion-extension was slightly affected by two of the individually made braces in one action. Running a figure eight was slower with two of the individually made braces. The best braces, one individually made and one ready-made, limited rotation and abduction-adduction effectively, but did not affect performance. Minor differences in design may account for differences in effect and may alter the protection afforded by a brace.