Mismatch negativity (MMN), the deviance-elicited auditory deflection, explained

The current review constitutes the first comprehensive look at the possibility that the mismatch negativity (MMN, the deflection of the auditory ERP/ERF elicited by stimulus change) might be generated by so-called fresh-afferent neuronal activity. This possibility has been repeatedly ruled out for the past 30 years, with the prevailing theoretical accounts relying on a memory-based explanation instead. We propose that the MMN is, in essence, a latency- and amplitude-modulated expression of the auditory N1 response, generated by fresh-afferent activity of cortical neurons that are under nonuniform levels of adaptation.     

Rodent models for compulsive alcohol intake

Continued seeking and drinking of alcohol despite adverse legal, health, economic, and societal consequences is a central hallmark of human alcohol use disorders. This compulsive drive for alcohol, defined by resistance to adverse and deleterious consequences, represents a major challenge when attempting to treat alcoholism clinically. Thus, there has long been interest in developing pre-clinical rodent models for the compulsive drug use that characterizes drug addiction. Here, we review recent studies that have attempted to model compulsive aspects of alcohol and cocaine intake in rodents, and consider technical and conceptual issues that need to be addressed when trying to recapitulate compulsive aspects of human addiction. Aversion-resistant alcohol intake has been examined by pairing intake or seeking with the bitter tastant quinine or with footshock, and exciting recent work has used these models to identify neuroadaptations in the amygdala, cortex, and striatal regions that promote compulsive intake. Thus, rodent models do seem to reflect important aspects of compulsive drives that sustain human addiction, and will likely provide critical insights into the molecular and circuit underpinnings of aversion-resistant intake as well as novel therapeutic interventions for compulsive aspects of addiction.     

Attentional modulation of stimulus representation in human fronto-parietal cortex

Evidence from primates suggests that prefrontal and parietal regions selectively represent information that is relevant for current behavior. In humans, whilst functional imaging has shown that fronto-parietal areas are activated by a range of different cognitive demands, the actual content of representation remains unclear. The current report describes two studies designed to address this issue using fMRI adaptation. In both studies, participants completed a delayed matching task where they attended to either the color or the shape of a series of sample stimuli and indicated whether occasional test stimuli matched the preceding sample on the attended dimension. Whole brain contrasts showed that changes to the value of the currently attended dimension produced significantly greater responses in frontal and parietal areas than events where the value was repeated. In addition, prefrontal and parietal regions of interest showed strong interactions between the currently attended dimension and the type of stimulus change, reflecting an attentional modulation of responses to stimulus change. Further comparisons suggested that the differences between attended changes and stimulus repetitions carried information about specific stimulus values, and did not simply reflect a generic response to attended changes.     

偏头痛患者个性特征、应对方式及其与头痛发作相关性的研究

目的:探讨偏头痛患者个性特征、应对方式及其与头痛发作的相关性.方法:选择113例偏头痛作为观察组,另设76例健康人作为对照组,采用艾森克个性同卷、应对方式同卷、偏头痛诊断疗效评定标准进行测评.结果:观察组神经质、自责、退避等因子分显著高于对照组,内倾向和求助因子分显著低于对照组(P<0.01);自责、退避等与神经质呈显著正相关,解决问题、求助与精神质呈显著负相关(P<0.01);内向不稳定患者头痛程度、发作频率显著高于外向稳定患者(P<0.01).结论:多数偏头痛患者个性特征和应对方式存在一定的缺陷,头痛发作与个性缺陷和不成熟的应对方式密切相关.     

《黄帝内经》天人相应观与妇人月事

"天人相应"解释了自然界的变化规律与人体活动变化之间的某种联系,是<黄帝内经>的重要思想之一.文章以妇人月事的生理、病理、治疗及调护等作为纵向层面,以月之盈亏、四时气侯、昼仪晨昏等作为横向层面,对<黄帝内经>有关妇科方面的论述进行剖析,探讨<黄帝内经>之"天人相应"观在妇科方面的应用.     

Oculomotor responses to on-axis rotational stepping in normal and adaptively altered podokinetic states

Previous studies investigated adaptive properties of a podokinetic (PK) system that senses and controls angular movement of the trunk relative to the stance foot when walking around a curved trajectory or during rotational stepping on the spot. In particular, after adaptively modifying the PK system by prolonged stepping-in-place over the axis of a horizontally rotating platform, blind-folded subjects could no longer step in place on firm ground. When trying to do so they invariably rotated themselves relative to space without perceiving their rotation, a phenomenon termed podokinetic after-rotation (PKAR). It is well known that normal rotational stepping generates a specifically podokinetic component of compensatory nystagmus which is independent of the VOR. The present study investigated whether during PKAR this podokinetic component of oculomotor activity follows the somatosensory correlate of actually stepping around, or the cognitive intent or percept of 'no rotation'. Experiments were conducted in two phases on five normal human subjects. In the first phase, the normal passively induced VOR was compared with the combined VOR and PK oculomotor response induced by intentional rotational stepping on the spot. In both cases the angular stimulus was a 2-min rotation at 15 degrees/s. Subtraction of the decaying VOR from the actively induced combined response revealed a constant podokinetic nystagmus with slow-phase velocity gain of about 0.4 maintained throughout this period. The PK and VOR response components appeared to sum linearly. In the second phase, we measured oculomotor activity during PKAR, when the blindfolded subjects involuntarily rotated themselves at around 15 degrees/s while attempting to step-in-place after the podokinetic adaptation procedure noted above. The striking result of the second phase of experiments was that, although an apparently normal decaying VOR was present, the maintained PK component of response was consistently absent, despite an essentially normal physical pattern of rotational stepping. Thus, in the adapted state, non-vestibular oculomotor activity followed the cognitive intent or percept of 'no rotation', rather than the prevailing somatosensory-motor activity of the lower limbs. The finding points to an important cognitive element in this form of oculomotor control.     

Caloric stimulation during short episodes of microgravity

Summary Caloric testing was performed during parabolic flight at the NASA Reduced Gravity Facility in Houston, Texas. Six test subjects were stimulated with continuous unilateral air insufflation (25°R), in a manner similar to the experiments performed in the extended weightlessness of orbital flight during the SL1 and D1 Spacelab missions. Nystagmus response was recorded by electro-oculography and eye video image. It was the purpose of the experiments to re-examine the apparent discrepancy between the disappearance of caloric nystagmus during short episodes of weightlessness and the finding that caloric responses can be elicited during periods of extended weightlessness. The present results agree with those of earlier experiments in that a prompt reduction of caloric nystagmus occurs on transition from hypergravity (1.8 G) to weightlessness. The time constant of nystagmus decay was estimated to be approximately 2–3s, a value which cannot be explained by cupular mechanics. A central gating mechanism involving the labyrinthine canal and otolithic afferents is proposed for the observed modulation of caloric nystagmus.     

Effect of spaceflight on thresholds of perception of angular and linear motion

Summary Psychophysical studies of vestibular function have been carried out in order to study adaptation within the vestibular sensory system to the weightless environment of orbital spaceflight. No significant change in the threshold of detection of whole-body angular acceleration was found, either during flight or post-flight. Experiments involving the perception of whole-body linear acceleration have yielded somewhat inconsistent results, although the weight of evidence points to an elevation and increased variability of threshold in the first few days following spaceflight. Although a change in the excitability of the saccular and macular otoliths in microgravity cannot be excluded, it is more probable that this decreased sensitivity is a manifestation of a central adaptive mechanism, in which the weighting of gravi-receptor information is reduced. Enhancement of the ability to detect linear acceleration stimuli, exhibited by some astronauts in microgravity, may be a manifestation of heightened utilization of cutaneous rather than otolithic cues.Part of the Round Table Conference presented at the Collegium ORLAS, Munich, Federal Republic of Germany, 7–10 September 1986     

Second-order neural responses after contralateral vestibular nerve sectioning

The characteristics of the response to an 8 degrees/sec2 acceleration of 41 neurons in the medial vestibular nucleus of the cat following vestibular nerve sectioning were compared with those of 73 control neurons at the same site. In 14 of the vestibular nerve-sectioned animals the same neuron was recorded before and after sectioning. No difference was found between the resting discharge rates, maximal response rates, and rates of adaptation of the two groups. Following contralateral vestibular nerve sectioning Type II neurons were still plentiful, suggesting many receive ipsilateral labyrinthine innervation.     

Événement greffe et adaptation psycho-sociale : étude de sujets dialysés versus greffés

Every year, in France, amongst a population of 60 million inhabitants, about 5000 patients are registered on a transplant waiting list and hope to find in this therapy a solution for their disease, a relief of their handicap, some hope of survival. On 1800 cerebral deaths, only 1000 gave organs used for 3000 transplants, saving many human lives. Unlike people suffering from cardiac and hepatic diseases, end-stage renal patients can use renal haemodialysis during the waiting period. Unfortunately, these patients must follow this treatment for a long time due to a lack of organs. Thanks to medical progresses in transplantation therapeutics, renal patient's mortality during the first year is very low, i.e. about 2%, what is very weak. It's about 7% for the first 5 years and 15 % for 10 years. For renal graft survival, 90% of the patients have a functional transplant at the end of their first transplantation year, 80% of them keep it five years later and 65% ten years later. But how did the patients who received an organ transplant live such an event? This study reports on the quality of life of 24 renal transplant patients and 20 ESRD patients. What are the differences between patients on a waiting list and the transplanted patients about their body image, self-esteem and social adjustment? Our methodology is based on a questionnaire on social adjustment, body image scale and a self-esteem inventory created respectively by M. Weissman, M. Bruchon-Schweitzer and S. Coopersmith. The results of this study show that patients had a better body image after their graft. However renal transplant didn't improve their self esteem and social adjustment.