诱导排尿反射对急性酒精性意识障碍患者催醒作用的研究

为了观察以呋塞米注射液诱导排尿反射对急性酒精性意识障碍患者促醒的作用,将30例急性重度酒精中毒患者纳入观察,随机分为2组,每组15例.两组患者均予补液,营养支持,纠正水电解质、酸碱平衡等对症处理.对照组予注射用纳洛酮2mg,加入5％葡萄糖溶液中静滴,纳洛酮日总用量不超过4.0mg.观察组在对照组基础上,加用呋塞米注射液20mg静脉推注,1次/日.对照组治疗后平均苏醒时间为1.85h±0.26h,观察组治疗后平均苏醒时间为1.28h±0.22h,经t检验,t=6.481 7,P＜0.01,提示观察组疗效优于对照组.笔者认为,以呋塞米注射液诱导排尿反射对急性酒精性意识障碍患者有较好的促醒作用,不仅与促进酒精代谢有关,兴奋觉醒中枢亦是其可能的机制.     

The Interrater Reliability of Subjective Assessments of the Babinski Reflex

The Babinski reflex is a clinical diagnostic tool; however, the interrater reliability of this tool is currently greatly contested. A comparison between rater groups with objective measurements of the Babinski reflex was therefore conducted. Fifteen recorded Babinski reflexes were assessed by 12 neurologists and 12 medical students as being either pathological or nonpathological. Kinematic and electromyographic variables were collected and used to assess which aspects of the Babinski reflex predict classification. Substantial interrater agreement within the neurologist and student groups (κ = .72 and .67, respectively) was shown; however, there were some differing aspects between what neurologists and students used to assess the reflex as determined by objective kinematic measurements.     

Self-motion perception and vestibulo-ocular reflex during whole body yaw rotation in standing subjects: the role of head position and neck proprioception

Self-motion perception and vestibulo-ocular reflex (VOR) were studied during whole body yaw rotation in the dark at different static head positions. Rotations consisted of four cycles of symmetric sinusoidal and asymmetric oscillations. Self-motion perception was evaluated by measuring the ability of subjects to manually track a static remembered target. VOR was recorded separately and the slow phase eye position (SPEP) was computed. Three different head static yaw deviations (active and passive) relative to the trunk (0°, 45° to right and 45° to left) were examined. Active head deviations had a significant effect during asymmetric oscillation: the movement perception was enhanced when the head was kept turned toward the side of body rotation and decreased in the opposite direction. Conversely, passive head deviations had no effect on movement perception. Further, vibration (100 Hz) of the neck muscles splenius capitis and sternocleidomastoideus remarkably influenced perceived rotation during asymmetric oscillation. On the other hand, SPEP of VOR was modulated by active head deviation, but was not influenced by neck muscle vibration. Through its effects on motion perception and reflex gain, head position improved gaze stability and enhanced self-motion perception in the direction of the head deviation.     

Similar effects of attention directed to acoustic and tactile stimuli on prepulse inhibition of acoustic startle

Prepulse inhibition (PPI) is assumed to index automatic and controlled processing. In three experiments (n= 32, 22, and 30) participants were asked to judge the duration of a prepulse in comparison with a stimulus presented 4000 ms before the prepulse. A distracter was presented simultaneously with the prepulse to increase the cognitive demands of the task. PPI was assessed at stimulus onset asynchronies (SOAs) of 30-150 ms, and 420 ms. The prepulse was either a tone (60 dB) or a tactile stimulus (21 kPa), and startle was elicited by 95 dB white noise. Directing attention to the prepulse increased PPI at SOAs of 60 ms and longer in all experiments, but the sensory modality to which attention was directed played only a minor role. We conclude that directing attention to both acoustic and tactile prepulses increased PPI.     

Modulation of tendon tap reflex activation of soleus motor neurons with reduced stability tandem stance

Reduced stability while standing typically decreases the soleus muscle Hoffmann (H-) reflex amplitude, purportedly to prevent the Ia afferent signal from excessively activating spinal motor neurons during the unstable stance. H-reflex measures, however, by excluding the spindle do not reflect the actual effect of the Ia pathway (i.e. the combined effects of spindle sensitivity and Ia presynaptic inhibition) on motor neuron activation, as tendon tap reflex measures can. But the effect of stance stability on soleus muscle tendon tap reflex amplitude is largely unknown. This study examined 30 young adults (mean(s), 21(2) years) as they stood in a wide stable stance position and an unstable tandem stance with a reduced base of support. Standing body sway, the amplitude of the soleus muscle tendon tap reflex, background EMG and tap force were measured in both stances. A repeated measured design t-test was calculated for each variable. Most subjects (69%) decreased tendon tap reflex amplitude when in the tandem stance position (mean decrease 11.6%), compared to the wide stance (wide stance 0.248(0.124) mV, tandem stance 0.219(0.119) mV, p < 0.05, Cohen’s d = 0.24 small) with no significant differences in background soleus and tibialis anterior EMG, and tap force across the stances. There was no relationship between the modulation of the tendon tap reflex amplitude across the stances and standing body sway in the tandem stance. Results support the idea that for most subjects examined, during a less stable stance the Ia excitation of motor neurons is decreased, likely by presynaptic inhibition, thereby avoiding potential instability in the reflex loop or saturating the reflex pathway and possibly interfering with descending control of the involved spinal motor neurons.     

Functioning of peripheral Ia pathways in leg muscles of newly walking toddlers

Monosynaptic and polysynaptic spinal level reflexes in the leg muscles of infants show significant dispersion across muscles, high variability, and no change in response patterns over the first 10 months. Here we tested the hypothesized relation between early walking experience and the tuning of these responses in three primary gait muscles of participants in four subgroups: cruisers (n = 7) and toddlers with one (n = 5), two (n = 5), or three (n = 5) months of walking experience. Reflex responses in multiple Ia pathways – tendon reflex (T-reflex), vibration-induced inhibition of the T-reflex (VIM-T-reflex), and tonic vibration-induced reflex (VIR), were elicited by mechanical stimuli applied to the distal tendons of the quadriceps, gastrocnemius-soleus, and tibialis anterior of both legs. Walking skill was assessed via a GAITRite mat. Generally, walking experience seemed to be related to slowly emerging improvements and, depending on muscle tested and pathway, progress was quite varied. Amplitude and latency of reflex responses were more clearly impacted by age or leg length while the ratio or distribution pattern of reflex response among antagonist pairs of muscles was impacted by walking experience and skill. As walking experience increased, the ratio of reflex responses tended to increase for the stimulated and decrease for the antagonist reflex loops with distribution of the pattern shifting gradually toward a single type of reflex response in all tested muscles. The very slow tuning of these reflexes may underlie the many missteps and falls reported to occur during early walking and suggest that subsequent studies should continue to follow the developmental trajectory through the first year of walking experience.     

Responses of human ankle muscles to mediolateral balance perturbations during walking

During walking our balance is maintained by muscle action. In part these muscle actions automatically respond to the imbalance. This paper considers responses to balance perturbations in muscles around the ankle, peroneus longus (PL), tibialis anterior (TA) and soleus (SO). It is investigated if their action is related to previously observed balance mechanisms: the ‘braking reaction’ and the mediolateral ankle strategy.Subjects walked on a treadmill and received pushes to the left and pulls to the right in various phases of the gait cycle. Muscle actions were divided into medium latency R1 (100–150 ms), long latency R2 (170–250 ms), and late action R3 (270–350 ms). Short latency responses, before 100 ms, were not observed but later responses were prominent. With inward perturbations (e.g. pushes to the left shortly before or during stance of the right foot) responses in RPL were seen. The forward roll-over of the CoP was briefly stalled in mid stance, so that the heel was not lifted. Stance was shortened. With outward perturbations, pushes to the left shortly before or during stance of the left foot, responses in all three muscles, LTA, LSO, and LPL were seen. Our interpretation is that these muscle activations induce a ‘braking reaction’ but could also contribute to the ‘mediolateral ankle strategy’. The resultant balance correction is small but fast, and so diminishes the need for later corrections by the stepping strategy.     

Involuntary Rotations of a Steering Device Induced by Voluntary Rotations of the Head and Maintained Eccentric Head Positions

In a series of 4 experiments, the authors examined involuntary rotations of a steering device (handlebar or wheel) that were associated with periodic head rotations and eccentric head positions. Periodic head rotations resulted in isodirectional involuntary rotations of a horizontally arranged steering device of very small amplitude. When the orientation of a steering wheel was changed to vertical and to a backward tilt, the involuntary rotations were in the opposite direction. That pattern of results is consistent with the assumption that small movements of the shoulder girdle, which are associated with head turns and which cannot be prevented by mechanical immobilization of the shoulder, are propagated to the wheel, but is not consistent with previous suggestions that involuntary rotations of a steering device can result from the action of the tonic neck reflex. Effects that correspond to the pattern of the tonic neck reflex were found only when a spring-centered handlebar was held in an eccentric position; maintenance of the eccentric position was facilitated when the participant's head was turned in the opposite direction. The findings strongly suggest that head movements can result in involuntary movements of a steering device via different mechanisms.     

The etymology of basic concepts in the experimental analysis of behavior

The origins of many of the basic concepts used in the experimental analysis of behavior can be traced to Pavlov's (1927/1960) discussion of unconditional and conditional reflexes in the dog, but often with substantial changes in meaning (e.g., stimulus, response, and reinforcement). Other terms were added by Skinner (1938/1991) to describe his data on the rate of lever pressing in the rat (e.g., operant conditioning, conditioned reinforcement, negative reinforcement, and response induction and differentiation) and key pecking in the pigeon (shaping). The concept of drive, however, has largely disappeared from the current literature.