Information processing in severe disorders of consciousness: vegetative state and minimally conscious state.

OBJECTIVE: To study the presence of electrophysiological indicators of remaining cortical functions in patients with persistent vegetative state (PVS) and minimally conscious state (MCS). Previous electrophysiological and PET data indicated that some PVS patients have partially intact cortical processing functions. However, it remains unclear whether the reported patients were representative for PVS population or just some exceptional cases. Methods: Event-related brain responses to stimuli of different complexity levels, recorded in 98 patients with extremely severe diffuse brain injuries, 50 of which in PVS. Four main indicators of cortical functions were: (i) N1-P2 complex as an index of simple, undifferentiated cortical processing; (ii) mismatch negativity as an index of pre-attentive, probably unconscious, cortical orientation; (iii) P3 wave as an index of deep cortical analysis of physical stimuli, and (iv) brain responses to semantic stimuli. RESULTS: Cortical responses were found in all PVS patients with a background EEG activity > 4 Hz. All responses investigated, including those to semantic stimuli that indicated comprehension of meaning, occurred significantly above chance, though less frequently than in patients with severe brain injuries who were conscious. CONCLUSIONS: Cortical responses were lacking in most patients with severe EEG slowing (< 4 Hz). Follow-up data revealed that the presence of a mismatch negativity, a short disease duration, and the traumatic etiology were related to a better outcome. SIGNIFICANCE: The data show that in a subpopulation of PVS patients with preserved thalamocortical feedback connections, remaining cortical information processing is a consistent finding and may even involve semantic levels of processing.     

Impairment of Consciousness During Epileptic Seizures with Special Reference to Neuronal Mechanisms

Summary: Two neuronal structures, i.e., the cerebral cortex and the subcortical structures, were shown by clinical observations to be involved in maintaining consciousness. The alteration of consciousness during epileptic seizures is discussed with respect to these findings: Alterations of consciousness during epileptic seizures may be produced by subcortical, i.e., reticular formation, and/or cortical dysfunction followed by excessive, hypersynchronous neuronal discharges. An impairment of consciousness during absence seizures may be due mainly to cortical dysfunction; during complex partial seizures (CPS), it may be due to dysfunctional subcortical neuronal structures. The mechanisms underlying an alteration of consciousness are defined as causing "irritative" functional disturbances and/or as having "inhibitory" effects on consciousness-related structures.     

Ictal Oroalimentary Automatisms with Preserved Consciousness: Implications for the Pathophysiology of Automatisms and Relevance to the International Classification of Seizures

Summary: A patient showing seizures presenting ictal automatisms with preserved consciousness is reported. A 30-year-old, right-handed man with normal development and without family history of epilepsy was referred for surgical treatment of epilepsy. At 15 he began to have seizures, starting with an epigastric aura, occasionally developing automatisms (lip-smacking, chewing), sometimes followed by tonicxAonic convulsions. At the time of referral, he averaged six convulsive seizures per year and one nonconvulsive per week. His sleep EEG showed sharpened slow activity over the right anterior quadrant magnetic resonance imaging (MRI) showed a benign lesion in the mesial aspect of the right occipital lobe. Simultaneous video monitoring and intracranial EEG with subdural strips recording from the right temporal and occipital lobes was undertaken. During one seizure, he had pronounced oroalimentary automatisms while holding a conversation with a technician, answering her questions, and explaining details of his seizures. Memory of this event was preserved. At seizure onset, spike activity was seen at the mesial occipital strips. At mid-seizure, high-voltage sharpened delta was seen throughout the right hemisphere. Left-sided scalp electrodes remained relatively uninvolved. The lesion, a dysembryoplastic neuroepithelial tumour was removed. Surgery was followed by abolition of seizures described. Because it is agreed that complex partial seizures require impaired consciousness, a history of automatisms with retained consciousness usually suggests nonepileptic attacks. This case suggests that automatisms in epileptic seizures can take place with minimal loss of consciousness, particularly if there is widespread but unilateral involvement. The need for a revision of the International Classification is suggested.     

醒脑注射液对动物血细胞的影响

采用不同剂量的醒脑注射液给实验动物以腹腔或肌肉注射 ,于用药前及用药后不同时间对各剂量组动物的红细胞、白细胞及血小板进行观察计数 ,研究其对动物血细胞的影响。结果表明 :在用药前及用药后第 10、2 0、30天 ,各剂量组大鼠及狗的血细胞与对照组比较均无显著性差异 (P>0 .0 5) ,表明该药对上述动物血细胞无显著影响     

The temporal order of binding visual attributes

The brain processes distinct attributes such as colour and motion in anatomically largely segregated systems. Moreover, these two attributes are perceived with different latencies. Here, we show that the time required to bind these two attributes differs too. In psychophysical experiments, we determined minimal presentation times required to perceptually pair spatially separate pairs of stimuli consisting of colour or motion. Binding two colours required longer presentation times than binding the directions of two moving stimuli. Cross-attribute binding between colour and motion took longer than within-attribute binding. This was so even when the relative perceptual delay between colour and motion was compensated for, which accelerated colour-motion binding. Moreover, stimuli could be discriminated but not bound at fast presentation rates. Our results thus show that spatial binding is an attribute-specific process and faster within the same than across different attributes. Furthermore, the time required to bind attributes is independent of that required to process them, since colour is perceived before motion but requires longer time for binding. Finally, our results suggest that binding acts on attribute-specific neural representations of the stimuli at a late, perceptually explicit stage. These results lead us to conclude that spatial binding is separate from, and subsequent to, stimulus processing and that it is an attribute-dependent and post-conscious process.     

Exclusion failure does not demonstrate unconscious perception II: evidence from a forced-choice exclusion task

Systematic failure to perform exclusion (making a response that opposes the participant's natural inclinations) for briefly displayed, masked words has been interpreted as evidence of unconscious perception. The present study required participants to make a forced-choice exclusion after viewing masked word targets. The forced-choice exclusion task was properly performed in all experiments, in contrast to previous studies that have utilized stem-completion as a dependent variable. The exclusion failure effects interpreted as unconscious perception in earlier studies appear to be caused by an insensitive dependent variable (stem-completion) rather than unconscious perception.     

Why Reject a Sensory Imagery Theory of Control Consciousness?

Mandik (2010) defends a motor theory of control consciousness according to which nonsensory states, like motor commands, directly contribute to the awareness we have of ourselves as being in control of our actions. Along the way, he argues that his theory is to be preferred over Prinz’s (2007) sensory imagery theory, which denies that nonsensory states play any direct role in the generation of control consciousness. I argue that Mandik’s criticisms of Prinz’s theory fall short, but that nonetheless there are reasons to favor a motor theory of control consciousness over a sensory imagery theory.     

多方位推进医德医风创新建设

随着社会的快速发展,科学技术的进步,卫生体制的深化改革,医学人文学科的地位日益彰显,其中医学伦理学面临着新的挑战和机遇。结合实际,围绕我院医德医风建设提出了从认清新形势,正确处理新关系;明晰新方向,把握好新控点;研究新情况,着力解决新问题;明确新思路,加强引导;探索新方法,始终坚持“三个新统一”;瞄准新目标,牢固强化新意识;总结新经验,始终保持清醒等七个方面。     

双水平无创正压通气治疗慢性阻塞性肺疾病伴意识障碍疗效研究

目的:探讨双水平无创正压通气（BiPAP）对慢性阻塞性肺疾病（COPD）并发重度呼吸衰竭伴有意识障碍患者的治疗效果。方法:将42例慢性阻塞性肺疾病并发重度呼吸衰竭伴有意识障碍的患者随机分成两组:常规组和BiPAP组。BiPAP组在常规治疗基础上,同时给予BiPAP通气治疗,比较两组患者在血气分析指标、住院时间、有效率、无效率、死亡率等方面的差异。结果:BiPAP组治疗（2～12）h后有13例患者神志转清,（12～24）h后有5例患者神志转清;常规组（2～12）h后有4例患者神志转清,（12～24）h后有10例患者神志转清。常规组和BiPAP组pH值和PaO2均升高,PaCO₂均下降（P<0.01）,BiPAP组的改善程度明显优于常规组,统计学有明显差异（P<0.05）。结论:BiPAP可以用于慢性阻塞性肺疾病并发重度呼吸衰竭伴有意识障碍患者,其疗效确切。     

Patients in a vegetative state following traumatic brain injury display a reduced intracortical modulation

Objective

Patients in coma who fail to wake develop a condition known as a vegetative state (VS). While we know that some cortical activities exist in patients in VS, it remains unclear whether interneuronal modulation can be abnormal in the cerebral cortex of these patients. The aim of the study was to evaluate the inhibitory and excitatory interneuronal circuits in patients in VS following a traumatic brain injury.

Methods

Cortical excitability was studied in 5 VS patients and in 10 healthy subjects using paired pulses transcranial magnetic stimulation (TMS). Resting motor threshold and intracortical inhibition and facilitation at short intervals (2 and 10 ms, respectively) were evaluated. Two patients were studied again after their level of consciousness transitioned into a minimally conscious state (MCS).

Results

Both intracortical inhibition and facilitation were significantly reduced in patients compared to healthy subjects (p < 0.05). In addition, these results did not significantly change in the 2 patients who evolved into a MCS.

Conclusions

This is the first report showing an abnormal cortical excitability in patients in VS.

Significance

Our findings suggest a pathophysiological base for future work aiming to restore the lack of interneuronal transmission in patients in VS.