Lateralized rewarding brain stimulation affects forepaw preference in rats

Rats trained to reach for food pellets into a narrow tubular feeder consistently prefer to perform this stereotype instrumental movement with either the left or right forepaw. In 16 rats with established handedness electrodes were implanted into both lateral hypothalami. The animals were rewarded by intracranial self stimulation (ICSS, 300 msec, 50 Hz, 20-60 microA) for reaching into a modified feeder for a plastic ball operandum, the movement of which between the bottom and entrance of the feeder was monitored by mechanical contacts. The rats readily continued to reach when ICSS was delivered immediately after the photoelectrically detected reach or after the displacement of the operandum. Most rats learned in a single session to modify the movement when ICSS delivery was made contingent upon holding the operandum between the bottom and entrance of the feeder for 256 or 512 msec. The efficiency of reaching (ratio of successful reaches to all reaches) decreased with increasing holding time; only a few animals were able to master a 1024 msec delay. Reaching was supported by ICSS of either lateral hypothalamus. Whereas in 8 rats the strongly expressed forepaw preference was not changed by lateralized ICSS, in 8 latently ambidextrous animals stimulation of the lateral hypothalamus ipsilateral to the preferred forepaw increased reaching with the normally non-preferred forepaw from 15% to 60%. Stimulation of the lateral hypothalamus contralateral to the preferred forepaw did not change the preference. The preference shift was equally well expressed in simple and difficult versions of the task. It is concluded that lateralization of motivational influences can be reflected in the asymmetry of the neural mechanisms processing the lateralized sensory signals and/or elaborating the lateralized motor output.     

Behavioral phenotyping of mice in pharmacological and toxicological research

The evaluation of behavioral effects is an important component for the in vivo screening of drugs or potentially toxic compounds in mice. Ideally, such screening should be composed of monitoring general health, sensory functions, and motor abilities, right before specific behavioral domains are tested. A rational strategy in the design and procedure of testing as well as an effective composition of different well-established and reproducible behavioral tests can minimize the risk of false positive and false negative results in drug screening. In the present review we describe such basic considerations in planning experiments, selecting strains of mice, and propose groups of behavioral tasks suitable for a reliable detection of differences in specific behavioral domains in mice. Screening of general health and neurophysiologic functions (reflexes, sensory abilities) and motor function (pole test, wire hang test, beam walking, rotarod, accelerod, and footprint) as well as specific hypothesis-guided testing in the behavioral domains of learning and memory (water maze, radial maze, conditioned fear, and avoidance tasks), emotionality (open field, hole board, elevated plus maze, and object exploration), nociception (tail flick, hot plate), psychiatric-like conditions (porsolt swim test, acoustic startle response, and prepulse inhibition), and aggression (isolation-induced aggression, spontaneous aggression, and territorial aggression) are described in further detail. This review is designed to describe a general approach, which increases reliability of behavioral screening. Furthermore, it provides an overview on a selection of specific procedures suitable for but not limited to behavioral screening in pharmacology and toxicology.     

Preprocessor Adapts Cardiovascular Signals to a Minicomputer

A laboratory-developed analog signal processor, driven by a conventional polygraph recorder and associated signal conditioning devices, provides automatic heart beat-by-heart beat preprocessing of various cardiovascular functions for input to a laboratory-type minicomputer. The technique of preprocessing individual functions, integrated with the minicomputer system which includes an A/D converter and teletype as input-output peripherals, provides a low-cost data acquisition and reduction system for the on-line computation and analysis of cardiovascular functions in experimental research applications. Such preprocessing more efficiently uses the minicomputer's memory to handle large amounts of information since the digitized data is in the form of one data sample, per function, per heart beat. Preprocessing analog data provides a low density data format and simplified software programs that are ideally suited for the utilization of a minicomputer in this on-line application.     

工作记忆、执行功能、加工速度与数学障碍儿童推理和心算能力的关系

目的：探讨工作记忆、执行功能、加工速度与数学障碍儿童推理和心算能力的关系。方法：采用智力测验、成就测验、教师提名、学业成绩相结合的综合标准甑选数学障碍儿童，在长沙市三所小学随机选取4-6年级共12个班，从中抽取24名数学障碍儿壹和24名学习正常儿童。对两组儿童进行工作记忆、执行功能、加工速度以及数字推理、图案推理和心算测验。结果：数学障碍组的工作记忆、执行功能及加工速度测验成绩均屁著低于学习正常组（P〈0．001—0．05），数学障碍组数字推理、图案推理和心算成绩也湿著低于正常组；数字推理、图案推理及心算成绩与听觉工作记忆、视觉工作记忆、执行功能和加工速度均有显著相关；逐步回归分析结果显示，进入推理能力回归方程的自变量有听觉工作记忆和视觉工作记忆；进入心算的回归方程的是听觉工作记忆和加工速度。结论：数学障碍儿童存在工作记忆、执行功能和加工速度缺陷；数学障碍儿童的推理能力低于正常学习儿童，主要可由工作记忆能力不足来解释，而心算能力低下则可由听觉工作记忆和加工速度共同解释。     

The thymus is a site of mast cell development in chicken embryos

Thymic mast cells were studied by light and transmission electron microscopy in chicken embryos during organogenesis. Mast cells made their first appearance at day 15. At days 16 and 17, there was a burst of mast cell development with a peak of 278 ± 54 cells/mm² at day 16. Then, mast cell density decreased until hatching. During the whole embryonic period, about 80% of mast cells localized to the thymic medulla. In the cortex, they were less numerous, and some rare mast cells could be identified in the capsule and septa. Thymic mast cells could be recognized in association with hematopoietic foci, but frequently they grew independently from areas of hematopoiesis and appeared as single cells interspersed among thymocytes, thymic epithelial cells, and interdigitating cells. They were often recognized in close relationship with the scanty and delicate extracellular matrix of the developing gland. Viewed by electron microscopy, mast cells were relatively small cells, with a few secretory granules. Exocytosis was never seen, but, notably, granules emptied in a piecemeal degranulation fashion. This study demonstrates that the chicken thymus is a site of mast cell development during embryogenesis. The high mast cell density we found suggests a possible role for these cells during thymus organogenesis.     

Finite element solution of steady state temperature distribution in the human torso

A finite element model of the steady state temperature distribution in the human torso is developed. The torso is approximated by a circular cylinder of core surrounded by a layer of muscle and insulating layers of fat and skin. The model is simplified by neglecting longitudinal heat flow. The region occupied by a circular cross-section of the torso is discretized into a mesh of triangles and the boundary of the torso, that is, the skin surface, is consequently approximated by a polygon. The elliptic partial differential equation governing the steady state temperature distribution, together with the associated boundary conditions, are expressed in equivalent variational form. Linear basis functions are used and the resulting integral is minimized over the region bounded by the approximating polygon. Results for two numerical experiments are determined by solving systems of linear equations.     

Bilateral interactions in saccade programming

Subjects were required to make a saccade to a target appearing randomly 4° to the left or right of the current fixation position (1280 trials per experiment). Location cues were used to direct visual attention and start saccade preparation to one of the two locations before target onset. When the cue indicated the target location (valid trials), the generation of express saccades (visually guided saccades with latencies around 100 ms) was strongly facilitated. When the opposite location was cued (invalid trials), express saccades were abolished and replaced by a population of mainly fast-regular saccades (latencies around 150 ms). This was found with a peripheral cue independently of whether the fixation point was removed before target onset (gap condition; experiment 1) or remained on throughout the trial (overlap condition; experiment 2). The same pattern also was observed with a central cue that did not involve any visual stimulation at a peripheral location (experiment 3). In the case where the primary saccade was executed in response to the cue and the target appeared at the opposite location, continuous amplitude transition functions were observed: starting at about 60–70 ms from target onset onward, the amplitude of the cue-elicited saccades continuously decreased from 4° to values below 1°. The results are explained by a fixation-gating model, according to which the antagonism between fixation and saccade activity gives rise to multimodal distributions of saccade latencies. It is argued that allocation of visual attention and saccade preparation to one location entails a successive disengagement of the fixation system controlling saccade preparation within the hemifield to which the saccade is prepared and a partial engagement of the opposite fixation system.     

几个常用执行功能测验在抑郁症中的应用

本文回顾了几个常用执行功能测验在抑郁症研究中的应用情况,包括威斯康星卡片分类测验（WCST）、Stroop色词测验、连线测验（TMT）、Go/no go任务,以及N-back任务。另外,对已有研究中存在的问题进行了讨论和展望。     

强迫症患者认知功能与病期的关系

目的：探讨强迫症的认知功能障碍与病期的关系。方法：分别用韦氏记忆测验，数字划销测验和威斯康星卡片分类测验评估25例急性强迫症和36例慢性强迫症患者的记忆、注意和执行功能。结果：急性强迫症患者的记忆测验中记图和数字划销测验中第二阶段失误率显著性较慢性强迫症差，其余两组间记忆测验、划销测验和威斯康星卡片分类测验各量表分无显著性差异。结论：强迫症的认知功能与病期无明显相关。     

Immunogenicity and tumor-inhibiting effects of HSP-antigen peptide complex in melanoma B16 cells in mice

目的 :黑色素瘤 B1 6细胞热休克蛋白 -抗原肽复合物 (HACs)及其粗提物 (HAC- CEs)的制备 ,以及它们的免疫原性和抑瘤效应的研究。方法 :应用 Sephacryl S- 2 0 0凝胶过滤制备HAC- CEs,应用亲和层析纯化 HACs,并测其免疫功能和抑瘤效应。结果 :应用凝胶过滤制备的HAC- CE3、HAC- CE4、HAC- CE5和应用亲和层析纯化的 HAC60 ,HAC75和 HAC97均不同程度地降低肿瘤发生率、延迟肿瘤发生时间和减少移植黑色素瘤 C57BL/6J小鼠死亡率 ;同时 ,伴有小鼠脾细胞 IFN-γ和 IL- 2分泌活性及 CTL杀伤率的增加。结论 :分子量为 60 0 0 0～ 970 0 0的 HACs具有免疫原性和抑瘤效应 ,本研究为制备肿瘤疫苗提供重要的实验依据。