Lateralized regular spatial patterns in oscillating drawing arm movements of right-handed young women

There is a lacuna in literature with reference to the spatial lateral difference in fast rhythmical movements produced by the whole dominant and nondominant whole arm, where spinal regulation has a significant role. Based on a fast oscillating zigzag drawing task, this study focused on (a) creation of a specific model of the task based on the intermittencies of coupled vectors of the fast motion, (b) identification of the spatial patterns that triggered these vectors, and (c) identification of quantified lateral differences between the spatial rhythmical patterns. 12 strongly right-handed young women performed 9 to 11 trials drawing zigzag lines. Each participant was required to extend her arm and perform this task using the left and right arm selectively on a frontally positioned graphic design system. The spatial patterns produced on each trial were identified in terms of five constant combinations of horizontal (X) and vertical (Y) projections of each line on the zigzag drawings. The dominant arm differed from the nondominant arm in preferred patterns. Because the duration of each line in the zigzag was highly restricted in time, the appearance of the patterns with different block schemes of movement could be explained as being associated with lower levels of the central nervous system. Initiation of fast movement of the total upper arm is probably associated with selection of the block scheme of motor control appropriate to each arm. Each block scheme is grounded on the coupled vectors of motion organised with particular muscle groups. Some block schemes seemed linked specifically to the dominant arm.     

Impact of instruction on the acquisition of sequence knowledge in a sensorimotor task

We examined whether and to what extent a sequence of finger movements can be learned and transferred to the untrained hand according to the muscle homology depending on the relative salience of response locations and effectors. Participants performed a discrete sequence production task, in which they were asked to learn a sequence of either key locations or of finger movements. Each training block was followed by a transfer block in which responding with the opposite hand was required. Before the last transfer block participants received an unexpected instruction. They had to reproduce the sequence of key locations instead of the sequence of finger movements and conversely, the sequence of finger movements instead of the sequence of key locations. The results do not support the existence of a sequence representation for the order of finger movements irrespective of the hand used.     

An acute application of transcranial random noise stimulation does not enhance motor skill acquisition or retention in a golf putting task

Transcranial random noise stimulation (tRNS) is a brain stimulation technique that has been shown to increase motor performance in simple motor tasks. The purpose was to determine the influence of tRNS on motor skill acquisition and retention in a complex golf putting task. Thirty-four young adults were randomly assigned to a tRNS group or a SHAM stimulation group. Each subject completed a practice session followed by a retention session. In the practice session, subjects performed golf putting trials in a baseline test block, four practice blocks, and a post test block. Twenty-four hours later subjects completed the retention test block. The golf putting task involved performing putts to a small target located 3 m away. tRNS or SHAM was applied during the practice blocks concurrently with the golf putting task. tRNS was applied over the first dorsal interosseus muscle representation area of the motor cortex for 20 min at a current strength of 2 mA. Endpoint error and endpoint variance were reduced across the both the practice blocks and the test blocks, but these reductions were not different between groups. These findings suggest that an acute application of tRNS failed to enhance skill acquisition or retention in a golf putting task.     

The performance of a simple motor task with kinaesthetic sense loss

Two related studies were carried out, to test the suitability of the nerve compression block as a technique in the investigation of kinaesthesis in motor skills.

In both studies a key tapping task was used. Each experimental group was composed of six volunteer subjects. It was found that kinaesthetic sensation was eliminated after pressure had been applied for 20-25 min., but muscle power was not seriously affected at this stage of the block. The results also showed a pronounced performance decrement in the absence of kinaesthetic feedback, and that this decrement was not due to emotional or other disturbances caused by the experimental procedure. The loss of tactile sensation was also observed.     

The Strength Model of Self-Control

ABSTRACT— Self-control is a central function of the self and an important key to success in life. The exertion of self-control appears to depend on a limited resource. Just as a muscle gets tired from exertion, acts of self-control cause short-term impairments (ego depletion) in subsequent self-control, even on unrelated tasks. Research has supported the strength model in the domains of eating, drinking, spending, sexuality, intelligent thought, making choices, and interpersonal behavior. Motivational or framing factors can temporarily block the deleterious effects of being in a state of ego depletion. Blood glucose is an important component of the energy.     

Vision,proprioception and corollary discharge in a movement recall test

Movement recall was investigated in relation to the sensory processes involved in a triangle drawing task.Forty subjects in two groups, one with and one without visual feedback, performed a recall task involving movements of their index finger. All subjects attended different experimental sessions in which (1) all proprioceptive feedback was eliminated by the ischaemic block technique, (2) muscle spindle feedback was distorted by vibration of the muscles and tendons involved in the movement, and (3) proprioceptive feedback was normal.Within each session subjects were required firstly to recall triangular movements made for them passively by the experimenter, and secondly, to recall movements they had made actively. Results indicated comparable accuracy in recall of active movements in all conditions, and a decrement in passive recall dependent on the availability of the alternative sources of feedback. The results indicated a process of integrated contribution of all inputs to the perception of movement; redundancy in information when all channels are available; and a role of corollary discharge in recall of movements.     

What do fully paralyzed awake humans feel when they attempt to move?

Subjects are able to judge the strength of muscle contraction. In theory, the force of muscular exertion could be perceived either from mechanoreceptor afferents or from knowledge of central motor command (corollary discharge). Sensations of great effort or exerted force have been described by subjects when their limbs were weakened by fatigue or partial paralysis. This has been taken as evidence that effort sensations arise from central motor commands rather than from mechanoreceptor afferent signals produced by muscle contraction. To differentiate between these possibilities, we used neuromuscular block to completely paralyze four waking subjects and required them to attempt maximal contraction of inspiratory muscles and of hand muscles. They were questioned after recovery about what their sensations were when attempting these contractions. None described the sensations of exerted force, great effort, or heaviness, which would have been expected if motor commands alone were the source of these sensations. The contradiction between our findings and those previously reported suggests that the specific neural mechanisms for effort sensations must be reexamined.     

The properties of object representations constructed during visual search in natural scenes

To investigate properties of object representations constructed during a visual search task, we manipulated the proportion of trials/task within a block: In a search-frequent block, 80% of trials were search tasks; remaining trials presented a memory task; in a memory-frequent block, this proportion was reversed. In the search task, participants searched for a toy car (Experiments 1 and 2) or a T-shape object (Experiment 3). In the memory task, participants had to memorize objects in a scene. Memory performance was worse in the search-frequent block than in the memory-frequent block in Experiments 1 and 3, but not in Experiment 2 (token change in Experiment 1; type change in Experiments 2 and 3). Experiment 4 demonstrated that lower performance in the search-frequent block was not due to eye-movement behaviour. Results suggest that object representations constructed during visual search are different from those constructed during memorization and they are modulated by type of target.     

The psychophysics of the kinesthetic aftereffect in the Petrie block experiment

Kinesthetic size is reported in the Petrie experiment by a simultaneous size comparison in which a standard block held between the thumb and forefinger of one hand is matched in size by moving the thumb and forefinger of the opposite hand along a wedge until the proper width is reached. After a baseline is obtained, a kinesthetic aftereffect is produced by rubbing a block of contrasting size followed by a return to the standard block. Experiments with 22 male Ss and 20 female Ss, tested in separate cycles, show that augmentation following stimulation with a block smaller than standard and reduction following stimulation with a block larger than standard are both statistically significant, and, at least for augmentation, the aftereffect persists for at least 48 h. When the data are corrected for regression there is no significant relationship between initial baseline and the amount of augmentation or reduction; reasons why such a relationship has been reported are indicated. The results suggest that when this kind of experiment is used for the study of individual differences (a) it is satisfactory to derive augmentation and reduction scores by subtracting the baseline from the absolute scores, provided the scores are corrected for regression, and (b) a counterbalanced order of presentation is not advisable in view of the carryover of augmentation from one day to the next, which is likely to make the two orders incommensurate.     

咪达唑仑—舒芬太尼靶控输注辅助神经阻滞用于颈部手术临床观察

观察咪达唑仑复合舒芬太尼TCI及恒速输注辅助颈丛阻滞颈部手术的镇痛镇静效果及对术中知晓、血液动力学和呼吸的影响,将80例择期颈部手术患者,随机分为2组各40例：咪达唑仑复合舒芬太尼TCI组（A组）;咪达唑仑复合舒芬太尼恒速输注组（B组）。比较二组MAP,HR,RR,SpO2等及术中镇痛、镇静、术中知晓和各种不良反应发生情况。发现A组血液动力学较B组更加稳定。提示TCI辅助颈丛阻滞麻醉安全有效,镇痛良好,无术中知晓,较恒速输注血液动力学更稳定,呼吸抑制少。     

Interaction between transient change in local muscle structure and segmented leg motor responses

We investigated the interaction between transient change in the local structure of gastrocnemius muscle fibers and the segmented leg motor responses elicited by toes-up rotation of the support surface. The gastrocnemius muscle in healthy young subjects underwent a sustained 2-min, isometric stretch (Prestretch group), followed immediately by the rotations. Analysis showed that the prestretch affected the amplitude of the monosynaptic but not the automatic components of the medial gastrocnemius muscle responses (monosynaptic response: 93 +/- 20% of the mean of the last three rotations in the Prestretch group compared to 174 +/- 42% in the Control group; automatic response: 128 +/- 18% in the Prestretch group versus 123 +/- 31% in the Control group). The shortened tibialis anterior muscle response and the onset latencies of responses were not affected by prestretching the gastrocnemius muscle. The prestretch effect on the amplitude of the monosynaptic (mediated by group Ia afferents) but not the automatic gastrocnemius muscle response (mediated by group II afferents) suggests that the automatic component of the muscle response to platform rotations has a stronger supraspinal influence than the monosynaptic response and is thus less affected by local events such as prolonged stretching.     

H-reflexes during a motor skill acquisition task

H-reflex amplitudes were studied during the acquisition of a motor skill involving coordinated isometric plantarflexion at the ankle joints as subjects learned to trace a triangular pattern on an oscilloscope screen by controlling plantarflexion torque applied against load cells. Torque feedback was presented on a subject oscilloscope with the right foot controlling a vertical cursor and the left foot a horizontal cursor. Eleven subjects reached criterion performance. H-reflexes were recorded from the right soleus and timed to the initiation of soleus muscle activity to plantarflex the foot. Average time to complete one trial decreased from 9 sec. in the prelearning block to 4 sec. postlearning. No single learning strategy was evident as subjects varied widely in their levels of H-reflex amplitude, but during postlearning, H-reflex amplitude became consistent within subjects as tracing performance became faster and accurate.     

Effects of mastery criterion on the emergence of derived equivalence relations

In this study, we manipulated mastery criterion form (rolling or block) and stringency (across 6 or 12 trials) and measured the emergence of derived relations. College students learned neuroanatomy equivalence classes and experienced one of two rolling mastery criteria (6 or 12 consecutive correct responses) or a block mastery criterion (12 trials in a block) during training. The study found that block and rolling mastery criteria produced similar outcomes. Effectiveness was hampered when the criterion was less stringent.     

高低情感开放性者概率内隐序列学习进程差异

大五人格情感开放性子量表(openness/feeling)能否预测内隐序列学习的问题存在争议。本研究采用概率性内隐序列学习范式, 比较高低情感开放性者在各反应刺激间隔(response stimulus interval, 即RSI)的差异。发现：(1) RSI = 0 ms和250 ms, 高分组在转移组块后习得高概率序列, RSI = 500 ms及以上在其之前习得; 所有RSI点低分组都在其之前习得。每个RSI点只有高分组习得低概率序列。证明随RSI增加两者内隐进程有本质差异, openness/feeling子量表可预测内隐序列学习个体差异。(2)低概率序列可作为测量概率性内隐序列学习及个体差异的新指标, 经典转移组块、再认、生成任务的测量效果却十分有限。     

The effect of prediction accuracy on choice reaction time

In this study, we examined the effect of prediction accuracy on reaction time (RT). Subjects performed on three blocks of choice RT trials, all of which involved the mapping of four stimuli (red, green, 1, or 0) onto two response keys. The subjects were told that the four stimuli were equally probable and that their task was to respond to each stimulus onset by pressing the correct key. In one block (stimulus-prediction), the subjects predicted, prior to each trial, the precise stimulus that would appear. In a second block (category-prediction), the subjects predicted the category of the stimulus (i.e., color or digit) that would appear. In a third block (no-prediction), the subjects simply responded to each stimulus without making a prior prediction. In the stimulus-prediction block, RT was faster for correct predictions than for incorrect predictions. In addition, RT was faster on trials in which an incorrect prediction involved the correct category than on trials in which it involved the incorrect category: that is, a "half-wrong" prediction was better than an "all-wrong" prediction. In the category-prediction block, RT was faster when the stimulus category was predicted correctly than when it was not. There was little evidence of a response-facilitation contribution to the correct-prediction effect. These results permit inferences concerning the encoding and organization of information in memory.     

The Effect of Training on Preparatory Attention in Older Adults: Evidence for the Role of Uncertainty in Age-Related Preparatory Deficits

Thirty-two older adults and 20 younger adults completed a simple visual detection task in which the preparatory interval (PI; 1, 3, and 5 s) that separates the warning signal from the target varied randomly on each trial. Participants were divided into two groups. In a control condition, participants completed four blocks of trials with the three PIs occurring equally often within a block. In the experimental condition, participants completed an equal probability block (Block 1) followed by two blocks (Blocks 2 and 3) in which the shortest PI (1 s) occurred on 2/3 of the trials, followed again by an equal probability block (Block 4). In Block 1, the results indicated a larger PI effect in older than younger participants, independent of general slowing. Increasing the likelihood of the shortest PI (Blocks 2 and 3 in the experimental condition) improved RT in older and younger adults and led to an equivalent PI effect in both age groups. This was not observed in the control condition, in which the age-related difference persisted during the four blocks of trials. Importantly, the improvement observed in the experimental group was maintained in the fourth block, where the PIs were reverted to an equal probability distribution. This supports the hypothesis that elderly participants prepare for events that have the greatest probability of occurrence and that this is a flexible process that can be modulated with brief training.     

Reinforcement of inhibitory positional priming by spatial working memory contents

This study examined whether positional priming of pop-out is modulated by spatial working memory (WM). In Experiments 1A and 1B, observers were presented with a to-be-memorized item (Experiment 1A: triangle; Experiment 1B: circle) prior to performing a block of search trials, with triangular stimulus configurations (one target, two distractors) on an underlying elliptical frame. Each search block was followed by a memory test (i.e., memory conditions). In Experiment 1C, the presentation of the memory item (triangle) was immediately followed by the memory test, and the search block was performed after this test (i.e., no-memory condition). It was found that targets presented at a previous target were detected faster and targets presented at a previous distractor location slower, relative to a previous empty (‘neutral’) stimulus location, respectively. While facilitatory position priming was uninfluenced by the memory manipulation, inhibitory positional priming was larger in the memory than no-memory condition, but only when the memory stimulus (triangle) matched the (triangle) configuration formed by the three search items. This finding of larger inhibitory priming under memory conditions provides further evidence that positional priming, rather than being purely bottom-up determined, is open to top-down influences.     

Sensory and motor impairment in the nerve compression block

Recently nerve compression block as a method of investigating movement control without kinaesthetic feedback has been questioned on the grounds that motor impairment (as measured by nerve conduction parameters) is a confounding factor. In order to clarify the relationship between sensory and motor function, behavioural data was obtained on both at systematic time intervals throughout the duration of the block. The findings indicated that significant decrements in tapping measures occurred somewhat earlier in the time course of the block than decreases in kinaesthetic discrimination. Also, contrary to assumption, the majority of subjects ceased to perform prior to total kinaesthetic loss. The data suggest that motor impairment is a “crucial” issue (Laszlo, 1966) in the use of this technique, and provide further behavioural support for the neurological findings of Kelso, Stelmach and Wanamaker (1974).     

Rapid picture presentation and affective engagement

Emotional reactions were assessed to pictorial stimuli presented in a continuous stream at rapid speeds that compromise conceptual memory and the processing of specific picture content. Blocks of unpleasant, neutral, or pleasant pictures were presented at the rate of either three pictures per second or seven pictures per second. Even with rapid presentation rates, startle reflexes, corrugator muscle activity, and skin conductance responses were heightened when viewing unpleasant pictures. These effects were stronger later in the aversive block, suggesting that cumulative exposure increasingly activates the defense system. The findings suggest that, despite conceptual masking inherent in rapid serial visual presentation, affective pictures prompt measurable emotional engagement.