Exploring the mechanism of dishabituation

In this study we explored elicitation and habituation of the orienting reflex (OR) in the context of indifferent and significant stimuli, particularly aiming to clarify the mechanism driving dishabituation. An in-depth analysis of the mechanisms of electrodermal habituation and dishabituation was conducted, focusing on the role of state measures as determinants of the phasic response profile. Twenty-four young adult participants completed an auditory dishabituation task while electrodermal activity was recorded. Participants listened to a series of 10 innocuous tones of the same frequency (standards), followed by a deviant tone of a different frequency, and succeeded by 2-4 tones of the same frequency as the initial 10 stimuli. All stimuli had a random stimulus onset asynchrony of 5-7 s. Participants completed an indifferent condition in which there was no task in relation to the stimuli, and a significant condition where instruction was given to count the stimuli silently; order was counterbalanced between participants. As predicted, both skin conductance responses (SCRs) and skin conductance levels (SCLs) were larger for the significant than the indifferent condition. The initial phasic ORs were dependent on pre-stimulus arousal level, and there were significant decreases in both SCR and SCL over the first 10 standards in both conditions. Phasic response recovery was apparent to the deviant stimulus, and dishabituation to the following standard stimulus; both effects were enhanced in the significant condition. Sensitisation was apparent in SCL following the initial and deviant stimuli, but the extent of this was confounded with incomplete resolution of the preceding phasic OR in the significant condition. In the indifferent condition, dishabituation was independent of deviant-related sensitisation; this could not be tested in the significant condition. These findings suggest that dishabituation is not a process of sensitisation, but rather, a disruption of the habituation process.     

胎教音乐对胎儿影响的实验研究

该项研究从三个方面探讨了胎教音乐对胎儿的作用。结果发现：胎教音乐可以使胎动时间延长,并证明在胎儿后期即存在条件反射;胎儿出生后能够再认胎教音乐,说明在胎儿后期已经存在听觉记忆;胎儿的性别及神经活动类型是影响其对音乐反应的重要因素。该研究的意义在于：证明了胎儿期心理现象的存在。把对“胎儿期有无心理现象”的历史争论引入了心理学的实验过程。     

Changes in Limb Stiffness Under Conditions of Mental Stress

In 2 experiments, the effects of mental stress on limb stiffness were investigated. The relative contribution to arm stiffness of individual muscle activity, co-contraction, muscle reflexes, and postural adjustments were examined. In each experiment, participants (N = 24, Experiment 1; N = 16, Experiment 2) held their supinated hand under a tray that they were required to return to horizontal after it had been suddenly released. Electromyographic activity in the biceps and triceps muscles was recorded, as were elbow and wrist angles and tray displacement. In Experiment 1, mental arithmetic stress was shown to lead to decreased tray displacement (i.e., increased resistance) compared with displacements under the control, unstressed condition, as well as to increased elbow flexion before tray release. In Experiment 2, the increased resistance to perturbation caused by mental stress was found to be independent of initial elbow angle, but to vary as a function of the amount of upward force exerted before tray release. The authors conclude that stress-induced increases in limb stiffness result from changes in the initial position of the elbow, specified by its angle, together with the initial force exerted by participants to counteract the mechanical perturbations.     

Precueing Response Factors in Choice Reaction Time

This note discusses the assumption researchers make when movement attributes are precued in a choice reaction time (RT) paradigm—i.e., that the precue only reduces the number of response alternatives, so that changes in RT reflect the programming time for the unprecued attributes. However, it is argued that since the precue reduces the number of stimulus alternatives, changes in RT reflect changes in both stimulus processing and response programming. Therefore, the interpretation made by Klapp (1977), using the precue paradigm, that response selection and response timing are not independent sequential stages in the programming sequence, is not necessarily correct.     

Memory and Perceptual Trace Development in Ballistic Timing

Adams’ (1971) closed-loop theory holds that memory and perceptual trace development is a function of the amount of practice with knowledge of results. If knowledge of results is withdrawn before these two memory states are strong performance will worsen, but after substantial practice performance can be maintained and evaluated in the absence of knowledge of results. To test the first prediction, three independent groups were given varying amounts of KR trials prior to early knowledge of results withdrawal. Subjects attempted to produce a 24.13-cm movement in exactly 150 msec. Memory and perceptual trace performance (as reflected in mean absolute and mean absolute estimated error, respectively) were dependent on the amount of knowledge of results practice, and the memory and perceptual trace remained reasonably strong during late knowledge of results withdrawal.     

The dynamics of successive induction in larval zebrafish

Charles Sherrington identified the properties of the synapse by purely behavioral means—the study of reflexes—more than 100 years ago. They were subsequently confirmed neurophysiologically. Studying reflex interaction, he also showed that activating one reflex often facilitates another, antagonistic one: successive induction, which has since been demonstrated in a wide range of species, from aphids to locusts to dogs and humans. We show a particularly orderly example in zebrafish (Danio rerio) larvae; the behavior (locomotion) of larvae is low in dark and intermediate in light, but low in light and substantially higher in dark when dark followed light. A quantitative model of a simple dynamic process is described that readily captures the behavior pattern and the effects of a number of manipulations of lighting conditions.     

不同地塞米松给药方法对芬太尼咳嗽反射的研究

探讨不同地塞米松给药方法对芬太尼咳嗽反射抑制的效果。选择200例全麻患者分为四组,按不同方法静脉注射地塞米松。诱导时芬太尼用量为5Mg·kg。观察各组患者出现咳嗽的例数和强度变化以及心率（HR）、平均动脉血压（MAP）、脉搏氧饱和度（SpO2）、脑电双频谱指数（BIS）的变化。结果显示,提前15min静注地塞米松组（Ⅰ组）咳嗽发生率为8％,与其他组有显著性差异。静注芬太尼2min时段Ⅰ组的HR、MAP和BIS与其他组相比有显著性差异。组内发生咳嗽反射患者HR、MAP明显升高,BIS值也有所回升。认为预先15min静脉注射地塞米松更有效降低麻醉诱导期间芬太尼所致咳嗽反射的发生。     

Habituation and migraine

The most reproducible and ubiquitous interictal abnormality of the migraineurs’ brain is lack of habituation in neuronal information processing. The underlying mechanisms are uncertain. Increased neuronal excitability, decreased inhibition or decreased pre-activation levels have all been proposed as possible culprits.The present review summarizes the available data on habituation in migraine patients obtained with different methodological approaches. We will discuss the change of habituation level over the migraine cycle and we will show that these data congruently indicate that the sensory cortices of migraineurs react excessively to repetitive, but not to a small series of stimuli.Although the precise cellular and molecular mechanisms of this hyper-responsivity must still be determined, we will describe experimental data suggesting that a dysrhythmic thalamo-cortical activity due to inadequate monoaminergic control might be a plausible explanation.     

Modality-repetition and attentional effects on reflex blinking in infants and adults

The ability of a brief prepulse to inhibit reflexively elicited startle is a robust phenomenon in adults of several species but is weak or absent in infants. The possibility that afferent processing of the prepulse is inadequate in infants was tested by assessing the integrity of two other types of reflex modulation that occur in modality-specific paths, that is, attenuation by repetition of same-modality stimuli and enhancement by modality-selective attention. The reflex, measured by electromyographic activity of the muscle controlling blink, was elicited by intense light flashes or noise bursts preceded by brief acoustic or visual prepulses and delivered during attention-directing acoustic or visual foregrounds that evoked cardiac deceleration. Modality-repetition effects were evidenced by smaller peak blink magnitude and longer latency of blinking to same than to different modality pairs and did not differ as a function of age (4-month-old infants or college students). Attention effects were also seen in both infants and adults and, in accord with previous findings, were evident in magnitude for infants and latency for adults. Thus, immaturity in paths mediating these effects could not explain delayed development of prepulse inhibition. Other possibilities include delayed maturation of extrinsic inhibition or of transient-processing systems.     

5-羟色胺基因缺陷增强急性应激后高唤醒状态

剧烈的应激刺激会引起持续的高唤醒状态, 是多种应激障碍的核心症状, 并推进其他症状的发生发展。本研究关注5-羟色胺在应激诱发高唤醒的发生、发展中的作用, 通过测量听觉惊吓反射水平反映高唤醒状态, 考察色氨酸羟化酶-2基因缺陷小鼠在天敌或电击应激前后高唤醒的变化。研究发现, 雄性基因缺陷小鼠在应激后出现持续一周以上的高唤醒表现, 而野生型小鼠高唤醒状态很快恢复。结果提示, 基因缺陷引起的5-羟色胺降低可能是强应激诱发的持续高唤醒的易感因素。