A temperature controller for in vitro recording chambers

An inexpensive, electrically quiet temperature controller designed to provide biological temperatures in chambers used to maintain tissue slices for in vitro recording is described. The circuit incorporates several advantageous features: (1) an integrated circuit temperature sensor is used which produces a linear output and is immune to self-heating error; (2) a single +12-18 V, 1 A DC supply will power the unit; (3) the output regulator cannot be damaged by overheating or short-circuiting; and (4) the temperature of the preparation is displayed.     

Thermal sensitivity in healthy subjects is decreased by a central mechanism after TNS

Using the thermal sense as a model for nociception, the effects of conventional and acupuncture-like transcutaneous nerve stimulation (TNS) were tested on thresholds for warm and cold sensation in 8 healthy subjects. Photic stimulation did not change the thermically neutral zone (the warm-cold difference limen) from that seen under baseline conditions. However, the thermal difference limen usually increased with both types of TNS. The effect was ipsi- as well as contralateral, implying that a central inhibitory mechanism is activated by conventional and acupuncture-like TNS.     

Volitional control of food transport and bolus formation during feeding

When healthy individuals eat solid food, chewed food is usually transported to the oropharynx where it accumulates before swallowing (stage II transport). We tested the hypothesis that this transport process can be altered by volition. Eight healthy young subjects ate 8 g pieces of cookie with barium while movements were recorded with videofluorography. There were two trials for each subject, each with different instructions: 1) without command: to eat the cookie in his/her usual manner; 2) with command: to chew the cookie, give a signal when ready to swallow, and then swallow on command of the investigator. We measured the number of chewing cycles, the duration of each stage in the feeding sequence, and the position of the leading edge of the barium at time of command and at swallow onset. Sequence duration was longer with than without command (P=0.02), primarily because of an increase in the number of chewing cycles (P=0.02). The leading edge was typically higher in the foodway at the time of swallow onset with than without command (P=0.06). Under the command condition, stage II transport was delayed, and transport to the valleculae was inhibited. Volition alters swallow initiation in both the timing and location of the food bolus relative to the airway.     

神经电生理检测在吉兰-巴雷综合征中的临床价值

目的探讨吉兰-巴雷综合征（GBS）的神经电生理特点及临床意义。方法对本院46例GBS患者的临床资料进行回顾性分析,分析患者神经功能损伤的Hughes评分和神经电生理检查的运动神经传导速度、复合肌肉动作电位、感觉神经传导速度及F波的变化,探讨其与GBS预后的关系。结果F波异常率[74．6％（47／63）]高于运动神经传导速度异常率[58．9％（106／180）],感觉神经传导速度异常率[19．8％（19／96）]低于运动神经传导速度异常率[58．9％（106／180）]和F波异常率[74．6％（47／63）]（P〈0．05）;急性炎症性脱髓鞘型组的预后[80％（24／30）]好于急性运动轴索性神经病组[50％（8／16）],其差异比较有统计学意义（P〈0．05）。结论电生理检查是GBS临床诊断的重要方法,F波是早期诊断的高敏感和高特异性指标,运动神经传导速度和复合肌肉动作电位动态检测是确诊、分型、判断预后的依据。     

Enhanced parasympathetic activity of sportive women is paradoxically associated to enhanced resting energy expenditure

The resting energy expenditure and the adaptation of the autonomic nervous system induced by sport activities in sedentary women and in female professional basketball players have been studied. Resting energy expenditure, body composition and the level of activity of the autonomic nervous system were measured before and after a period of six months. The physical activity induced an increase in resting energy expenditure and free fat mass without variations in body weight. Basketball players showed a significant increase in the parasympathetic activity, measured by the power spectral analysis of the heart rate variability. These findings demonstrate that resting energy expenditure is higher in the athletes than in sedentary women, despite the augmented parasympathetic activity that is usually related to lower energy expenditure.     

Effect of recombinant human growth hormone on peripheral nerve regeneration: experimental work on the ulnar nerve of the rat

Neurotrophic factors may be used to improve the growth and repair of injured peripheral nerves. In this study we determined the effectiveness of recombinant human growth hormone on peripheral nerve injury in the Wistar rat. The ulnar nerve of the rat was sectioned and its proximal and distal ends were sutured to either end of a silastic tube, with the aim of encouraging regeneration through the tube. 32 ulnar nerve specimens were randomized into two groups: 18 nerves regenerating under the influence of recombinant growth hormone, and 14 nerves regenerating in its absence. The study was performed over a period of 8 weeks and progression of regeneration was assessed with regular surface electroneurography every 1-2 weeks after surgery. In the group receiving recombinant growth hormone, it comprised a significant improvement in the recovery of conduction velocity, and a more gradual increase in the amplitude of motor potential from the fifth week onwards was observed. Histological analysis of study specimens in the recombinant hormone group revealed an improved architecture of the regenerating nerve, a greater density of nerve fibers, and increased myelination with a lesser degree of endoneural fibrosis. Our work demonstrates the positive effect of the administration of recombinant human growth hormone in obtaining significantly improved conduction velocities, and a greater improvement in nerve regeneration from the fifth week of monitoring when compared to the control group. Histological analysis in the group receiving hormone showed acceptable degree of myelination with little granulation tissue and fibrosis.     

Enhanced motor cortex facilitation in patients with vascular cognitive impairment-no dementia

Data on Transcranial Magnetic Stimulation (TMS) derived measures of cortical excitability and intracortical circuits in age-related white matter changes are scarce. We aimed to assess early changes of motor cortex excitability in nondemented elderly patients with subcortical ischemic vascular disease (SVD). Ten SVD elderly and ten age-matched controls underwent paired-pulse TMS for the analysis of intracortical inhibition (ICI) and facilitation (ICF). All subjects performed neuropsychological assessment and brain magnetic resonance imaging. SVD patients showed abnormal executive control function. No statistically significant differences were found for resting motor threshold, cortical silent period between SVD patients and controls or between the two hemispheres, in patients. A significant enhancement of mean ICF was observed in SVD patients. This study provides the first evidence of functional changes in intracortical excitatory neuronal circuits in patients with SVD and clinical features of vascular cognitive impairment-no dementia. Further studies are required to evaluate whether the observed change of ICF might predict cognitive and/or motor impairment in a population at risk for subcortical vascular dementia.     

Time to epileptiform activity and EEG background recovery are independent predictors after cardiac arrest

Objective

Investigate the temporal development of EEG and prognosis.

EEG neurofeedback research: A fertile ground for psychiatry?

The clinical efficacy of neurofeedback is still a matter of debate. This paper analyzes the factors that should be taken into account in a transdisciplinary approach to evaluate the use of EEG NFB as a therapeutic tool in psychiatry. Neurofeedback is a neurocognitive therapy based on human–computer interaction that enables subjects to train voluntarily and modify functional biomarkers that are related to a defined mental disorder. We investigate three kinds of factors related to this definition of neurofeedback. We focus this article on EEG NFB. The first part of the paper investigates neurophysiological factors underlying the brain mechanisms driving NFB training and learning to modify a functional biomarker voluntarily. Two kinds of neuroplasticity involved in neurofeedback are analyzed: Hebbian neuroplasticity, i.e. long-term modification of neural membrane excitability and/or synaptic potentiation, and homeostatic neuroplasticity, i.e. homeostasis attempts to stabilize network activity. The second part investigates psychophysiological factors related to the targeted biomarker. It is demonstrated that neurofeedback involves clearly defining which kind of relationship between EEG biomarkers and clinical dimensions (symptoms or cognitive processes) is to be targeted. A nomenclature of accurate EEG biomarkers is proposed in the form of a short EEG encyclopedia (EEGcopia). The third part investigates human–computer interaction factors for optimizing NFB training and learning during the closed loop interaction. A model is proposed to summarize the different features that should be controlled to optimize learning. The need for accurate and reliable metrics of training and learning in line with human–computer interaction is also emphasized, including targeted biomarkers and neuroplasticity. All these factors related to neurofeedback show that it can be considered as a fertile ground for innovative research in psychiatry.     

Cortical inhibitory dysfunction in epilepsia partialis continua: A high frequency oscillation somatosensory evoked potential study

ObjectiveThe pathophysiology of epilepsia partialis continua (EPC) is still unclear, a thalamo-cortical circuit dysfunction has been hypothesized.The aim of present study is the functional evaluation of the thalamo-cortical network in EPC by means of the study of low- and high-frequency somatosensory evoked potentials (LF-SEP and HF-SEP).MethodsMedian LF-SEP and HF-SEP were recorded in 3 patients with EPC and in 2 patients with rolandic lesions without EPC (non-EPC). Recording electrodes were placed on P3, C3, F3 and P4, C4, F4 of scalp regions. HF-SEP were obtained by an offline 400–800 Hz filtering of P3-F3 and P4-F4 traces.ResultsIn EPC patients, we found a significant suppression of post-synaptic HF-SEP burst and an amplitude reduction of the P24 wave of the LF-SEPs. Both these components are related to cortical inhibitory interneuron activity. HF-SEP and LF-SEP were normal in non-EPC patients.ConclusionThe different results obtained in patients with a rolandic lesion with and without EPC supports the hypothesis that EPC might be correlated to a dysfunction of gabaergic interneurons of a cortical sensory-motor network.SignificanceOur results might contribute to the understanding of the physiological basis of the cortical dysfunction causing epilepsia partialis continua.