Somatosensory Evoked Potential Changes With a Selective Attention Task

Somatosensory evoked potential (SEP) changes associated with selective attention were investigated. In 16 subjects, SEPs were recorded from five locations while they counted electrical stimuli to one of four randomly stimulated fingers. Sequential SEP events measured included peaks P30 (positivity at 30 msec). P45, N60, P100. N140. P190. N230, P400. Counting was associated with greater P45, P100. P190, N230, and P400 amplitudes; effects were not attributable to eye or tongue activity. Analyses designed to reveal changes associated with two conceptualized “channels” (finger class, hand) showed that the P45, P100, and P190 amplitude increases involved both channels. The P400 effect was limited to the target finger. Channel effects for N60 and N140 amplitudes resulted from decreases localized to the unattended element of one channel, suggesting “inhibition.” Latency effects involved mainly the hand channel; counted hand latencies were shorter for P30, P45, P100 and P190. The findings indicate modifications of both early and late electrocortical events with selective attention, and that changes can be of several kinds. They support the view that attention proceeds in more than one stage.     

Ensemble noise and current relaxation analysis of K+ current in single isolated salivary acinar cells from rat

The K⁺ channel in rat parotid gland acinar cells were investigated by ensemble current noise analysis in single isolated cells employing the giga-seal whole cell current recording mode. Sets of 20–40 identical de- and hyperpolarization voltage steps were applied and the resultant current records were processed by computer to obtain the mean and the variance of the current. The time-course of the mean current could be fitted by the sum of two exponentials, suggesting a 3-state model. The simplest plausible hypothesis is a model with one open and two closed states. Assuming this model, the relationship between the variance (₂) and the mean current (I) could be fitted by the function ₂/I=i–I/N. The estimated single channeli/V-relations were similar to those taken from single channel current recordings, and the size of the population of channels per cell (N) was 76±26 (n=12). The validity of the model was tested by a successful simulation of the time-course of the variance.     

中学生生活事件与抑郁的关系

目的：探讨中学生具体生活事件和抑郁状况的关系。方法：采用青少年生活事件量表和中学生抑郁量表对558名中学生进行问卷调查。结果：除个别生活事件项目外，青少年生活事件量表中的多数项目均与中学生抑郁呈显著正相关；生活事件与抑郁的回归分析表明，学习负担重，受人歧视冷遇，不喜欢上学，家庭经济困难，与同学或好友发生纠纷，升学压力，被盗或丢失东西，考试失败或不理想，受批评或处分，生活习惯明显变化，恋爱不顺利或失恋，被罚款等12类生活事件进入了对抑郁的回归方程，对抑郁的预测作用较大。结论：中学生生活事件与其抑郁存在广泛的正相关关系。12项生活事件对中学生抑郁有较大的预测作用。     

CD8+T-bet+ cells as a predominant biomarker for inclusion body myositis

Background

Myositis is a heterogeneous group of muscular auto-immune diseases with clinical and pathological criteria that allow the classification of patients into different sub-groups. Inclusion body myositis is the most frequent myositis above fifty years of age. Diagnosing inclusion body myositis requires expertise and is challenging. Little is known concerning the pathogenic mechanisms of this disease in which conventional suppressive-immune therapies are inefficacious.

Electrical properties of metallic electrodes

The series equivalent resistance R and capacitance C of metal/saline electrode/electrolyte interfaces were measured as a function of frequency (100 Hz–20k Hz) and current density (0·25 to 1000 A m⁻²) for eight typical electrode metals. For each of the metals tested, R decreased and C increased as the current density was increased above a critical value (with the exception of silver and MP35N at frequencies above 1 kHz for which R increased and C decreased slightly). With the exception of copper, the current density linearity limit (for 10 per cent decrease in R or 10 per cent increase in C) increased with increasing frequency and, in most cases, the current density linearity limit for 10 per cent increase in C was slightly less than that for 10 per cent decrease in R. Among the metals tested, copper and aluminium had the lowest current carrying capability and rhodium had the highest current-carrying capability. The current carrying capabilities of 316 SS, platinum, silver and MP35N, were intermediate and similar. With increasing current density, an increase in the electrode/electrolyte capacitance was the most sensitive indicator of the current-carrying linearity limit.     

SARS疫情期间公众心态影响及变化趋势分析

目的：探索重大突发性公共卫生事件对社会公众心理行为的影响，以及在不同阶段中公众心态变化的特点。方法：对SAILS流行期间374人次的心理咨询记录进行分析，依据疫情发展情况，比较各阶段的差异。结果：在咨询者中，女性(59．4％)多于男性(40．6％)；根据疫情变化将咨询记录数据划分为三个阶段，分析发现随着疫情缓和，针对SARS症状的咨询者显著减少，从13．1％降低到1．8％；有关社会生活的咨询者显著增多，从8．7％上升到12．3％；在有关情绪问题的咨询者中，伴有相关症状者显著减少，从23．0％降低到4．5％；不伴相关症状者显著增多，从77．0％上升到95．5％。结论：整个SAILS疫情期问，情绪问题始终占第一位；随SARS疫情缓和，社会公众对于疾病本身的关注减少，而与疫情有关的社会生活问题增多；面对突发性公共卫生事件，及时开通心理咨询热线电话是十分必要的。     

Providing Interdisciplinary Geriatric Team Care: What Does It Really Take?

We concur with Speer and Schneider's arguments (2003 ; this issue) that more psychologists should offer mental health services to older adults and that the primary care system is a good focus of such efforts. Three issues deserve more prominence in their review. First, their argument that older adults are averse to mental health services seems incorrect, given research indicating that older adults prefer psychotherapy to medication for treatment of depression. Second, psychologists working in primary care need to be aware of new Current Procedural Terminology (CPT) codes that allow documentation of psychological work in medical settings. Third, Speer and Schneider allude to interdisciplinary team functioning, but provide little information about models of team care or issues in developing a well-functioning interdisciplinary team; this commentary expands on those topics.     

Measurement of current spread from microelectrodes when stimulating within the nervous system

Summary Tungsten stimulating microelectrodes have been tested in monopolar, bipolar and concentric configurations for the extent to which unwanted current spread occurred. Current spread from monopolar electrodes in close conformity with the predictions of the inverse square law, both in vitro and in vivo. The bipolar and concentric configurations, tested only in vitro, had current-spread characteristics which did not follow the inverse square law so closely. The bipolar configuration gave little reduction in spread, compared with a monopolar electrode, but the concentric configuration did reduce the extent of stimulus spread. The extent of spread depends greatly upon a number of experimental variables, including the dimensions of the microelectrode tip. For studies requiring precise localization, with low stimulus currents, it is advisable to determine the inverse square law constant for each experimental situation. For more generalized stimulation purposes within the mammalian C.N.S., employing monopolar microelectrodes of moderate tip size, brief pulses of 10 A can be expected to stimulate myelinated axons within about 0.15 mm of the tip, and 100 A will stimulate within a radius of about 0.5 mm.The work was all done while E.V.B. was on Industrial Training leave from the North-East Polytechnic, Romford Road, London E. 15     

In support of hassles as a measure of stress in predicting health outcomes

We investigated the impact of frequently occurring minor stressors (hassles) upon health status in a sample of low-income, elderly persons with osteoarthritis. These individuals are characterized by conditions which are precursors to experiencing stress. Using a modified Hassles scale, we replicated some important findings in a sample demographically distinct from earlier studies on hassles. Specifically, hassles were better predictors of health status than major life change events, and the influence of life change events was indirect, i.e., it increased hassles, which in turn, negatively affected health status. Furthermore, hassles correlated strongly with validated indicators of health status. By replicating earlier studies in a demographically dissimilar sample, and by finding significant correlations between hassles and valid physical health measures, we have strengthened the conceptual development of hassles.     

Description of Heart-Rate Variability Data in Accordance With a Physiological Model for the Genesis of Heartbeats

A survey is presented of techniques which transform heart-rate variability data into a signal that is both visually informative and accessible for analysis. The Instantaneous Heart-Rate (IHR) signal is introduced, i.e. the signal having the value of the heart rate (inverse interbeat interval) during the interval concerned. The IHR signal differs from the standard Delayed Heart-Rate (DHR) signal, which is always one beat late. The relationship is discussed between the different representation methods and the Integral Pulse Frequency Modulation (IPFM) model, the latter being a physiologically plausible model for the transformation of a continuous input signal (e.g., nervous influence on the cardiac pacemaker) into a series of events (heartbeats). It is shown that when the IHR signal is used as input of the IPFM model, the event series from which the signal was derived appears at the output. Hence, if the IPFM model is accepted as a model of the pacemaker, the IHR signal may be considered as an approximation of the neural (sympathetic and parasympathetic) influence on the pacemaker. In addition we show that the appearance of the IHR signal is less affected by trigger errors or extrasystoles than the standard DHR signal. It is concluded that the most attractive time-domain representation of physiological event series consists of the IHR signal, because this signal, being conceptually and computationally simple, is consistent with the IPFM model.