COVIS神经生物学基础

本文论述了COVIS的神经生物学基础.COVIS假设类别学习过程中存在着两个系统的竞争,一个是以额叶为基础,依赖工作记忆和执行注意,采用逻辑推理的外显学习系统;另一个是由基底神经节调控,采用程序学习的内隐学习系统.COVIS外显系统的神经生物模型涉及的关键脑结构是前扣带回(ACC)、前额皮层(PFC)和尾状核头部(CD).模型中有两个独立的分支网络--一个负责在检验过程中将备选规则保持在工作记忆当中,调节注意从一个规则向另一个规则的转换;另一个负责生成或选择新的假设.COVIS内隐程序学习系统的关健结构是尾状核,来自黑质(SN),用于调节奖酬信号的多巴胺促进尾状核中的程序学习.     

Neurobiological implications of eating healthy

Over the last decades, the importance of food in the development of chronic diseases has been examined, as well as the medical value of eating healthy. The contribution of the eating process itself to health and well-being, however, has not been questioned until most recently. Biology has linked eating to appetitive motivational processes with their underlying neurophysiology, including CNS reward circuitries: Eating uses the pleasure-reward physiology to motivate us to eat. Endogenous opiates, such as morphine, insure our survival by helping us to make eating motivational via pleasure induction. After taking in enough food, we become satisfied, i.e., tolerant to food. Our appetite, and so is our appetence, are then low and need a certain time span to reach their former levels for then inducing food-seeking behaviors, food intake, etc. again. When tolerance passes, we once more engage in this pleasurable process related to positive behavioral motivation. Opioid receptor agonists, however, may induce energy intake even beyond an actual need. This interesting potential of opioidergic signaling may have its roots in biological mechanisms that insured the intake and storage of high energy foods, hence preparing for future famines. In our world of today, however, such neurobiological pathways may pose a threat on our health. Thus, feedback mechanisms, such as tolerance, aversion and satiety, have to be finely tuned. Therefore central autoregulation that involves, for example, limbic mu receptor signaling and other endogenous signaling compounds comes into the focus of modern science. The time where research recognizes the importance of neurobiological pathways such as endogenous opiate autoregulation or CNS reward circuitries for examining the physiology of food intake has yet begun. Many questions remain open and have to be answered through future scientific inquiry.     

Neurobiological approach to computing devices

According to the old metaphor of classical cybernetics the brain can be considered as a computer. Newer theoretical endeavours reverse the question and ask: what could neurobiology offer to engineers of near-future generation computer systems? Three not completely disjoint abstract functions of the nervous system, namely pattern formation, pattern recognition and action, can be treated in a unified conceptual framework. Storage and retrieval mechanisms of information are connected to fault-tolerant, adaptive parallel structures. "Learning" and "plastic behaviour" are interpreted in terms of the theory of non-linear dynamic systems. As neural development and plasticity can be approached by deterministic models superimposed by random influence, noise might also have a positive role to play during the operation of technical computing devices. Molecular computation is discussed in relation to eventual hardware realization of "neurobiology-based" computers.     

Neurobiological approaches in vertebrate paleontology

The study of the central nervous system in extinct vertebrates is discussed. Historical development of the nervous system is restricted to a few morphological patterns. The foundation of structural conservatism of the nervous system is provided by the multifunctional character of any adaptive changes in the brain of vertebrates. The functional structural features allow the use of the nervous system for the resolution of some difficult questions of vertebrate evolution.     

Neurobiological mechanisms of the origin of terrestrial vertebrates

Some trends in the phylogenetic changes of the vertebrate neural system in the course of their transition from aquatic to terrestrial mode of life are analyzed. Wide multifunctionality of the neural centers and heterotopic substitution of the brain functions are supposed to be prerequisites of transition of archaic amphibians to the land via a stable transitional environment. The latter include underground or vegetation aquatic-air labyrinths in which conditions of gradual acquisition of adaptations to the terrestrial mode of life occurred. The principal neurological adaptations to such mode of life and less dependence on aquatic environment developed during the long-term evolution in that environment. The neurobiological model of evolutionn of the archaic amphibians in the transitional environment of aquatic-air labyrinths suggested herewith is compared to other hypotheses of the tetrapod origin.     

Neurobiological basis of human recognition of facial emotion

In the review of modern data and ideas concerning the neurophysiological mechanisms and morphological foundations of the most essential communicative function of humans and monkeys, that of recognition of faces and their emotional expressions, the attention is focussed on its dynamic realization and structural provision. On the basis of literature data about hemodynamic and metabolic mapping of the brain the author analyses the role of different zones of the ventral and dorsal visual cortical pathway, the frontal neocortex and amigdala in the facial features processing, as well as the specificity of this processing at each level. Special attention is given to the module principle of the facial processing in the temporal cortex. The dynamic characteristics of facial recognition are discussed according to the electrical evoked response data in healthy and disease humans and monkeys. Modern evidences on the role of different brain structures in the generation of successive evoked response waves in connection with successive stages of facial processing are analyzed. The similarity and differences between mechanisms of recognition of faces and their emotional expression are also considered.     

两种复吸动物模型的神经生物学机制

复吸是指撤药一段时间后,觅药和用药行为的恢复。它是药物成瘾的主要特征之一,也是药物成瘾治疗亟待解决的头号难题。本文介绍两种复吸动物模型——自身给药消退恢复模型、条件性位置偏爱消退复燃模型建立的方法,对模型的效标效度进行评价,探讨复吸的神经生物学机制,为药物成瘾的治疗提供研究思路。     

鸣禽鸣叫学习的神经生物学机制

鸣禽鸣叫具有复杂的神经生理和生化基础,表现为一种复杂的学习过程。鸣啭控制系统是研究神经系统与学习、行为和发育关系的重要模型。而鸣禽鸣叫学习行为与鸣啭控制系统内长时程增强效应、神经元超微结构的改变和神经核团内的电活动、激素水平高低及其周期性变化、神经元再生或改变、即早基因的表达等方面密切相关。对鸣禽鸣叫的神经生物学机制进行了综述。     

Neurobiological studies of gamma-band bioelectrical activity in humans

The modem literature data were observed, which dedicated to the study of neurobiological studies of gamma-rhythm mechanisms, providing the cognitive functions in hymans: state of readiness and attention, providing of sensory indentification, perception and memorizations, decision-making, management of psychomotor response, emotional and semantic processing of an information. It was shown that synchronous gamma-activity is at integrative activity, which in deteriorated in pathology of thinking. Literature data were analysed concerning ot the changes of gamma-activity (spontaneous, evoked, provoked by photostimulation etc.) in a number of neuropsychiatric disorders: epilepsy, schizophrenia, Alzheimer's disease, attention deficit hyperactivity disorder, stroke etc. as compared with norm. The data observed testify to high significance of gamma-activity in the brain functioning.     

Mechanism of the radioprotective effect of cysteamine

The radioprotective effect of cysteamine combined with the modification of the chromatin state by sodium butyrate has been studied using V-79 and CHEL lines of Chinese hamster cells and HeLa cells. Sodium butyrate enhances the chromatin sensitivity to nucleases and removes the radioprotective effect of cysteamine as measured by the yield of cells with chromosome aberrations. As is indicated by changes in the intensity of fluorescence of the DNA-ethidium bromide complex, measured by laser flow cytometry, the protective agent decreases the binding of the dye with both irradiated and nonirradiated DNA whereas ionizing radiation and sodium butyrate increase thereof. It is concluded that the radioprotective effect of cysteamine depends in its ability to reduce the susceptibility of DNA to nucleases.