Inter-hemispheric remapping between arm proprioception and vision of the hand is disrupted by single pulse TMS on the left parietal cortex

Parietal cortical areas are involved in sensori-motor transformations for their respective contralateral hemifield/body. When arms of the subjects are crossed while their gaze is fixed straight ahead, vision of the hand is processed by the hemisphere ipsilateral to the arm position and proprioception of the arm by the contralateral hemisphere. It induces interhemispheric transfer and remapping. Our objective was to investigate whether a single pulse TMS applied to the left parietal cortical area would disturb interhemispheric remapping in a similar case, and would increase a simple reaction time (RT) with respect to a control single pulse TMS applied to the frontal cortical area. Two LED were superimposed and located in front of the subjects on the saggital axis. Subjects were asked to carefully fixate on these LED during each trial. The lighting of the red LED was used as a warning signal. Following the green one was illuminated after a variable delay and served as a go-signal. The hand for the response was determined before the start of each trial. TMS was applied to the left parietal, the left frontal cortical areas, or not applied to the subject. Results revealed that: (1) Irrespective of its location, single pulse TMS induced a non-specific effect similar to a startle reflex and reduced RT substantially (15 ms on average) with respect to a control condition without TMS (mean value = 153 ms). (2) Irrespective of TMS, RT were shorter when the right or the left hand was positioned in the right visual hemi-field (i.e. normal and crossed positions respectively). (3) Finally, RT increased when single pulse TMS was applied to the left parietal area and when hands were crossed irrespective of which hand was used. We concluded that interhemispheric sensori-motor remapping was disrupted by a single pulse TMS that was applied to the left parietal cortex. This effect was also combined with some visual attention directed towards the hand located on the right visual hemi-field.     

Medication for Complex Posttraumatic Disorders

Treatment guidelines and reviews of outcome studies agree that drugs are valuable for moderation of irrational moods and impulsivity that interfere with thoughtfulness and cooperativeness. As such, they empower patients to make good use of psychotherapy for mastery of the risk of betrayal in intimate relationships, which is the typical recurrent traumatic event in complex posttraumatic disorders. Psychotherapy, for its part, has demonstrated correction and lasting remission of disorder in the aftermath of certain kinds of single trauma and promises further development to achieve similar efficacy for complex posttraumatic disorders. This article summarizes the strengths and limitations of each class of psychiatric drugs. It explains how the natural course of complex posttraumatic disorders greatly contaminates observations of medication efficacy and fosters unrealistic expectations for drug development.     

Congruence or coherence? Emotional and physiological responses to colours in synaesthesia

Lexical–chromatic synaesthesia is a condition in which letters and/or words elicit percepts of synaesthetic colours, termed photisms. Anecdotal data suggest that synaesthetes are particularly sensitive to inconsistencies between their synaesthetic percepts and the real world, e.g., it can be annoying and unpleasant for them to see a letter printed in a colour different than the respective photism colour. For R, a synaesthete subject who participated in the present study, the photisms possess specific emotional values (a red photism is pleasing and attractive, green is repulsive and unpleasant, etc.). In contrast to the anecdotal data, R does not always find the colour–photism incongruence to be disturbing. More importantly, he states that it is the emotional coherence between the stimulus and the corresponding photism that matters. In a series of experiments, we studied this new concept of emotional coherence on three levels—subjective (self-report), behavioural, and physiological, corroborating R's introspective statements. Besides the implications of the concept of coherence itself, the results presented here suggest that even highly subjective cognitive constructs can be approached and measured experimentally, uncovering the workings of the underlying psychophysiological mechanisms.     

The effects of preexposure-test and conditioning-test intervals on the magnitude of latent inhibition

Using the conditioned taste aversion paradigm, two experiments were conducted to examine the effects of the interval between preexposure and test and that between conditioning and test on the magnitude of latent inhibition. Experiment 1 revealed that the degree of latent inhibition was attenuated when rats were given a 21‐day interval between preexposure and test. It was also found that this attenuation was more marked in subjects which were given conditioning immediately after preexposure than those which were conditioned shortly before the test. Retention interval between preexposure and test was reduced to 12 days in Experiment 2, and exactly the same pattern of results as those found in Experiment 1 was obtained. These findings suggest that the memory of conditioning as well as that of preexposure decreases its retrievability after a long retention interval, although the former is more retainable than the latter.     

Choice with delayed and probabilistic reinforcers: effects of prereinforcer and postreinforcer stimuli.

In Experiment 1, pigeons' pecks on a green key led to a 5-s delay with green houselights, and then food was delivered on 20% (or, in other conditions, 50%) of the trials. Pecks on a red key led to an adjusting delay with red houselights, and then food was delivered on every trial. The adjusting delay was used to estimate indifference points: delays at which the two alternatives were chosen about equally often. Varying the presence or absence of green houselights during the delays that preceded possible food deliveries had large effects on choice. In contrast, varying the presence of the green or red houselights in the intertrial intervals had no effects on choice. In Experiment 2, pecks on the green key led to delays of either 5 s or 30 s with green houselights, and then food was delivered on 20% of the trials. Varying the duration of the green houselights on nonreinforced trials had no effect on choice. The results suggest that the green houselights served as a conditioned reinforcer at some times but not at others, depending on whether or not there was a possibility that a primary reinforcer might be delivered. Given this interpretation of what constitutes a conditioned reinforcer, most of the results were consistent with the view that the strength of a conditioned reinforcer is inversely related to its duration.     

Persistence of acquired behavioral control in the context of imprinting

Newly hatched Khaki Campbell ducklings (Anas platyrhynchos domesticus) were exposed to a moving object that immediately suppressed distress vocalizations occurring in a novel environment. The static visual and auditory features of this object acquired the ability to suppress distress vocalizations after eight 20-min sessions of exposure to the object in motion. The acquired suppressive properties of these features were found to persist throughout thirty 20-min sessions given over 10 days. During these sessions, the ducklings were continually exposed to the static features in the absence of visual movement. In a second experiment, the ability of these features in the absence of visual movement. In a second experiment, the ability of these features to serve as reinforcement for a pecking response was shown to persist for up to 56 hr. In one duckling, presentations of the static visual features did not maintain pecking behavior. However, it was shown that pecking responses could be re-instated in this duckling by introducing novel stimuli to the environment.     

条件性恐惧记忆消退的提取干预范式及其作用的神经机制

基于记忆再巩固理论的恐惧记忆提取干预范式被证明可以有效消退恐惧记忆, 能克服传统消退容易复发的缺点。该范式通过单独呈现条件刺激激活原有恐惧记忆, 使记忆重返不稳定状态, 随后在再巩固时间窗内实施干预则能改写原有记忆。目前该范式起作用的神经机制尚不明确, 本文在现有的人类研究和动物研究基础上, 总结了杏仁核、前额叶和海马三个脑区在提取干预过程中的作用, 以及该领域研究的争议点, 为之后的研究提供思路。     

The Moro reaction: More than a reflex,a ritualized behavior of nonverbal communication

ObjectiveTo propose a phylogenetic significance to the Moro reflex which remains unexplained since its publication in 1918 because both hands are free at the end of the gesture.MethodAmong the 75 videos of healthy term newborns we have filmed in a research project on antenatal education to parenthood, we describe a sequence that clearly showed the successive movements of the Moro reflex and we report the occurrence of this reflex in the videos that were recorded from Time 0 of birth defined as the moment that lies between the birth of the thorax and the pelvis of the infant.ResultsThe selected sequence showed the following succession of the newborn’s actions: quick extension-adduction of both arms, the orientation of the body, head and eyes towards a human person, and full extension-abduction of both arms with spreading of the fingers, crying and a distressed face. There were 13 Moro reflexes between 2 and 14 s from Time 0 of birth. We found a significant association between the occurrence of the Moro reflex and the placement of the newborn at birth in supine position on the mother’s abdomen (p = 0.002).DiscussionThe quick extension-adduction of both arms which started the sequence may be considered as a startle reflex controlled by the neural fear system and the arm extension-adduction which followed as a Moro reflex. The characteristics of all Moro reflexes were those of ritualization: amplitude, duration, stereotype of the gestures. This evolutionary process turns a physiological behavior, grasping in this case, to a non-verbal communicative behavior whose meaning is a request to be picked up in the arms. The gestures associated with the Moro reflex: crying and orientation of the body, head, and eyes towards a human person, are gestures of intention to communicate which support our hypothesis. The neural mechanism of the Moro reaction probably involves both the fear and the separation-distress systems.ConclusionThis paper proposes for the first time a phylogenetic significance to the Moro reflex: a ritualized behavior of nonverbal communication. Professionals should avoid stimulating the newborns’ fear system by unnecessarily triggering Moro reflexes. Antenatal education should teach parents to respond to the Moro reflexes of their newborn infant by picking her up in their arms with mother talk.     

认知重评对负性效价的抑制促进条件性恐惧消退

认知重评能有效降低个体对情感刺激的负性情绪体验, 但指导性认知重评在恐惧记忆治疗中效果存在争议。本文将认知重评范式与辨别式条件恐惧反应范式结合, 以效价和US预期值为指标, 探讨指导性认知重评训练对恐惧情绪习得和消退的影响效果。以低认知重评能力个体为被试, 在实验前24 h进行指导性认知重评训练。条件性恐惧任务为期2天, 第一天完成条件性恐惧的习得和消退任务, 第二天完成条件性恐惧的再消退任务。结果显示, 经过重评训练后个体在条件性恐惧任务中的恐惧情绪效价显著较低, 说明认知重评有效降低低认知重评能力个体在急性应激状态下的负性情绪体验。所有被试均成功完成辨别式条件性恐惧的习得和消退任务, 因此重评训练并不削弱个体对危险或者安全信息的辨别能力。但在条件性恐惧的消退过程中, 认知重评指导训练加快了恐惧消退, 且24 h后测得的条件性恐惧程度显著较低, 说明指导性重评提高了条件性恐惧记忆的消退效率, 并减弱了条件性恐惧的消退返回。