Haptic localization and the internal representation of the hand in space

As the hand actively explores the environment, contact with an object leads to neuronal activity in the topographic maps of somatosensory cortex. However, the brain must combine this somatotopically encoded tactile information with an internal representation of the hand's location in space if it is to determine the position of the object in three-dimensional space (3-D haptic localization). To investigate the fidelity of this internal representation in human subjects, a small tactual stimulator, light enough to be worn on the subject's hand, was used to present a brief mechanical pulse (6-ms duration) to the right index finger before, during, or after a fast, visually evoked movement of the right hand. In experiment 1, subjects responded by pointing to the perceived location of the mechanical stimulus in 3-D space. Stimuli presented shortly before or during the visually evoked movement were systematically mislocalized, with the reported location of the stimulus approximately equal to the location occupied by the hand 90 ms after stimulus onset. This pattern of errors indicates a representation of the movement that fails to account for the change in the hand's location during somatosensory delays and, in some subjects, inaccurately depicts the velocity of the actual movement. In experiment 2, subjects were instructed to verbally indicate the perceived temporal relationship of the stimulus and the visually evoked movement (i.e., by reporting whether the stimulus was presented before, during, or after the movement). On average, stimuli presented in the 38-ms period before movement onset were more likely to be perceived as having occurred during rather than before the movement. Similarly, stimuli in the 145-ms period before movement termination were more likely to be perceived as having occurred after rather than during the movement. The analogous findings of experiments 1 and 2 indicate that the same inaccurate representation of dynamic hand position is used to both localize tactual stimuli in 3-D space and construct the perception of arm movement.     

Diurnal sleep/wake-related immune functions during the menstrual cycle of healthy young women

SUMMARY  Animal and human studies have related the sleeping/waking brain to the immune system. Because women are more susceptible to certain immunological illnesses, and sex steroids regulate immune functions, it was investigated whether the diurnal sleep/wake pattern of aspects of cellular immune functions and interleukin-1 (IL-1) and IL-2-like activities differed during low and high progesterone phases of the menstrual cycle.
Eleven healthy women, mean age 24y, were assessed over 24h with serial venous blood samples. Peripheral blood monocytes were assayed for mitogen responses, i.e. phytohemagglutin (PHA) and pokeweed (PWM) and natural killer (NK) cell activities. Plasma was assayed for IL-1 and IL-2-like activities, cortisol and progesterone. Data were standardized by Z transformation and analysed by repeated-measures analysis of variance by comparing high ( N = 5) vs. low ( N = 6) progesterone phases.
During the high progesterone phase, delayed slow-wave sleep (SWS) onset time and reduced amount of SWS was accompanied by a delay in the decline of NK cell activity, but rise in PHA activity following sleep onset. With the low progesterone phase, the pattern was similar to men with an early sleep decline in NK cell and late sleep rise in PHA activities. PWM rose during the night and plasma IL-1-like activity peaked during midday and during nocturnal sleep irrespective of the amount of progesterone.
Slow-wave sleep and sleep-related NK cell and PHA activities differed over the menstrual cycle, but not PWM response. Increases in plasma IL-1 functions during midday and night are consistent with predisposition to sleepiness during these times.     

Post-stroke depression: Relationships with morphological damage and cognition over time

The aim of the present study was to investigate the relationships between poststroke depression (PSD), lesion location and cognitive deficits after stroke. We studied 20 patients within the first month after clinical onset (T1), and one year later (T2). PSD was observed in 55% of patients at T1 and 35% of patients at T2. At T1, depression was reliably correlated with dorsal lesions in the right-hemisphere and anterior lesions in the left hemisphere. Lesion location was no longer a significant factor determining PSD at T2. Changes in PSD, from T1 to T2, were inversely correlated with the performances in cognitive tests exploring the domains of attention, visuospatial learning, executive/motor functions, and with the global composite cognitive score. Our data suggest that: 1) in the mix of influences that may produce PSD, lesion location is the main factor determining mood changes after stroke in the first month; 2) PSD produces deficits in attention, learning, and executive/motor functions, without affecting language and other cognitive domains.

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Sommario Scopo di questo studio sono i rapporti tra la depressione post-stroke (PSD), la localizzazione della lesione cerebrovascolare e i disturbi cognitivi conseguenti alla lesione. Abbiamo studiato 20 pazienti entro il primo mese dall'episodio ictale (T1) ed un anno dopo (T2). La PSD era osservabile nel 55% dei pazienti a T1 e nel 35% dei pazienti a T2. A T1, la PSD era significativamente correlata con lesioni dorsali nell'emisfero di destra e con lesioni anteriori nell'emisfero di sinistra. Queste correlazioni non erano più significative a T2. Le variazioni della PSD da T1 a T2 erano inversamente correlate con le prestazioni dei pazienti a compiti cognitivi di attenzione, apprendimento visuospaziale, funzioni esecutivo/motorie, e con un punteggio cognitivo composito.Questi dati suggeriscono che: 1) tra le numerose cause che possono produrre la PSD, la localizzazione della lesione sembra essere il fattore principale nel primo mese dopo l'episodio cerebrovascolare; 2) la PSD produce disturbi attentivi, di apprendimento visuospaziale ed esecutivi/motori senza determinare disturbi nella sfera del linguaggio e di altre funzioni cognitive.

     

某金矿凿岩工症状自评量表调查分析

探讨局部振动对工人心理,行为功能的影响。方法 应用ＳＣＬ－９０量表及一般症状查体资料,对４０名金矿井正业凿岩机工人及其对照组２０名工人进行了调查分析。结果 与对照组比较,凿岩组工人在耳鸣,听力下降,高血压等方面有显著性意义;症状量表听各项指标均与对照组有显著差异,且在工作后１０年内易发生。结论局部振动可造成工人心理,行为功能的改变及一些症状的出现,二者又可相互作用,进一步加重对工人身心健康的危害。     

High-frequency ultrasound examination of the wrist and hand

High-frequency ultrasound (US) is an efficient, rapid and inexpensive altenative to magnetic resonance imaging (MRI) for investigation of diseases in the soft tissues of the wrist and hand. US allows detection of foreign bodies and the reliable identification of a variety of traumatic lesions affecting tendons, annular pulleys, ligaments, vessels and nerves. Inflammatory diseases of tendons, including acute and chronic tenosynovitis and some degenerative conditions in the wrist and hand, can also be diagnosed. In entrapment neuropathies, US is able to identify nerve shape changes and possible extrinsic space-occupying lesions that may cause nerve compression within the tunnels. In patients with localized swelling of the hand or wrist, US is able to assess the presence of an expansile lesion and to characterize its nature in most cases. The objective of this article is to review the main findings and the primary indications of US in the investigation of disorders of the hand and wrist. Received: 10 September 1998 Accepted: 24 November 1998     

新型常规潜艇长航60昼夜对艇员体能耐力及心理工效的影响

目的;探讨新型常规潜艇长航６０昼夜对艇员视力听力,心肺功能、体能耐力和心理工效等的影响。方法：通过临床体检,特殊检查观察长航艇员生理和心理方面的变化。结果：长航艇员视力和听力下降,心率加快,心脏搏出量减少,用力肺活量及最大通气量减少,体能耐力和工作能力下降。结论：潜艇长航对艇员视力听力,心肺功能,体能耐力,工作能力和心理工效均有一定程度的影响。     

图形视网膜电图检测原发性开角型青光眼视网膜功能的意义

目的 观察原发性开角型青光眼图形视网膜电图的改变及其特点,了解ＰＥＲＧ在检测ＰＯＡＧＰＹ视网膜功能方面的意义。方法 对３６例（５９只眼）ＰＯＡＧ及３２例（５９只眼）年龄相匹配的正常人进行ＰＥＢＧ检测。结果 ＰＯＡＧ患者ＰＥＲＧ的ＡＰ１、ＡＮ２、ＡＮ１、ＡＮ２／ＡＰ１下降;运用ＡＮ２＋ＡＰ１〈２．７及ＡＮ２／ＡＰ１下降;运用ＡＮ２＋ＡＰ１〈２．７及ＡＮ２／ＡＰ１〈０．７的方法,对已确认的ＰＯＡＧ进行     

Neurotoxicity in operating room personnel working with gaseous and nongaseous anesthesia

Occupational exposure to high concentrations of anesthetic gases (more than 500 ppm of nitrous oxide and more than 15 ppm of halothane and enflurane) can cause neurobehavioral effects in operating room personnel. Factors such as stress and work organization play an additional role in reducing performance capacities. It is still unclear whether these conditions may become the predominant factor in behavioral impairment when exposure to anesthetic gases is reduced; in addition, we wished to ascertain the extent of neurobehavioral and neuroendocrine effects at relatively low levels of exposure to such gases. Therefore the same group of 30 operating room personnel was examined with neurobehavioral tests during gaseous and nongaseous anesthesia. In this way, the neuropsychological performance was examined under the same stress conditions, but with different exposure levels to anesthetic gases. Serum cortisol was measured as an additional biological stress indicator. Prolactin secretion was examined to study possible interference of anesthetic gases with the dopaminergic system. The results were compared with those in a control group of 20 hospital workers from other departments, with similar characteristics in respect of age, sex, and education. During work with gaseous anesthesia, average airborne concentrations (geometric mean) of nitrous oxide were 50.9 ppm (SD 20.8) on the first day of the working week and 54.2 ppm (SD 22.1) on the last day of the working week, whereas average urinary nitrous oxide (geometric mean) were 21.54 g/l on the first day of the working week and 25.67 g/l on the last day of the working week. The operating room workers showed slower reaction times at the end of the week with gaseous anesthesia, compared with workers using nongaseous anesthesia and the control group. At the same time they also showed increased secretion of prolactin, whereas cortisol remained unchanged. Therefore, it can be concluded that lower levels of exposure to anesthetic gases (and not only high exposure levels) cause an impairment of neurobehavioral performance, with the action of stress being less relevant. The mechanism of anesthetics' neurotoxic action seems to be related to interference with the dopaminergic system.     

Effects of cocaine on human nasal mucosa

Summary The effects of cocaine on the contractile response of isolated human nasal mucosal blood vessels to field stimulation and methoxamine were investigated. Results showed that cocaine antagonized methoxamine and inhibited field stimulation. The drug increased resting tension in human nasal mucosa in vitro through direct actions and potentiated mucosal contractions by norepinephrine and epinephrine. The study indicated that high concentrations of cocaine may actually antagonize -adrenoceptors, but these concentrations are not necessary in eliciting desired degrees of vasoconstriction in nasal blood vessels while being applied as a local anesthetic.