人脑视觉意识的神经机制

意识的存在决定了人类生命的意义.意识问题被认为是21世纪科学要回答的一个最重要问题.意识科学正在成为认知和心理科学的皇冠,成为基础科学的顶峰.近20年来,随着认知科学、心理科学、神经科学和脑成像技术的发展,人们开始通过实验科学地研究意识问题,特别是与视觉意识相关的研究工作取得了很多重要进展.在这篇综述中,我们对以往的视觉意识研究工作进行了总结,并对未来的研究方向进行了展望.     

视觉意识神经相关物的ERP研究进展

意识神经相关物是指充分地形成任意一个特定意识体验的最小神经机制。探究意识神经相关物是神经科学研究的重要问题。目前,通过采用事件相关电位技术,神经科学工作者发现三类潜在视觉意识神经相关物,即早期意识正成分、视觉意识负成分和晚期正成分。由于研究设计和实验范式存在不足,三类成分是否是视觉意识神经相关物还存在争议。本文对近些年采用事件相关电位技术研究视觉意识神经相关物的进展进行概略介绍,并主要对三类潜在视觉意识神经相关物的研究进行综述。     

中国科学院生物物理研究所视觉信息加工开放研究实验室研究课题申请指南

中国科学院生物物理研究所视觉信息加工开放研究实验室专门从事视觉信息加工研究,这是当前神经科学的主要研究内容之一。本开放实验室接受国内外神经科学家开展视觉信息加工研究的申请,一经批准即予以资助,并安排在本实验室工作。本实验室着重开展下列内容的研究工作:1.视觉通路和神经回路的研究,包括传递和加工视觉信息,如深度、形状、运动、颜色等的神经通路和回路。2.神经递质、调质、受体和离子通道在视觉各层     

组学技术及其在食品科学中应用的研究进展

后基因组时代的主要研究任务即是组学(转录组学、蛋白质组学及代谢组学)研究,其发展迅速,有望成为解决生命科学领域诸如食品品质与安全等科学问题的有力工具.组学研究为食品科学相关研究提供了新的思路和技术,在食品加工、贮藏、营养素检测、食品安全以及食品鉴伪等领域中已有广泛的应用.综述转录组学、蛋白质组学及代谢组学研究的核心技术,以及组学技术在食品科学研究中的研究进展,并对其应用前景进行展望.     

初级视觉的Gabor函数模型的研究进展

当前,模型和理论研究已成为视觉研究的重要组成部分.国际权威刊物“Vision Re-search”自1992年起把刊登内容分成三大栏目:神经生物学;心理物理和行为生理学;计算现觉.最后一部分是当年新增栏目.内容包括:视觉模型和理论;视觉网络:计算机视觉.视觉系统中的信息加工是神经科学中最早理论化和模型化的分枝之一,也是神经科学中与工程技     

中国科学院生物物理研究所视觉信息加工开放研究实验室研究课题申请指南

中国科学院视觉信息加工开放研究实验室专门从事视觉信息加工研究,这是当前神经科学的主要研究内容之一。 本开放研究实验室接受国内外神经科学家开展视觉信息加工研究的申请,一经批准即予以资助,并安排在本实验室工作。本实验室着重开展下列内容的研究工作:     

介绍一本跨学科研究的新书

《脑模拟与神经计算机》由北京大学心理学系和视听信息处理国家实验室的沈政、林庶芝合著,北京大学出版社1992年9月第一次出版,该书虽仅约25万字,却概括了计算机科学、神经科学、认识科学和心理科学中许多领域的基础理论和当代研究进展,包括作者自己实验室近年研究成果的总结和理论概括.该书共含六章,每章后均附有数十篇重要参考文     

fMRI在视觉研究中的应用和进展

视觉研究对于揭示大脑的奥秘有着极其重要的意义.功能性磁共振成像（functional magnetic resonance imaging,fMRI）用于研究人脑的功能结构,主要是基于静脉毛细血管内血氧浓度的变化.fMRI可以无损伤地在几毫米级的空间分辨率和少于1 s的时间分辨率上观察清醒状态下人脑的活动,因此自90年代以来fMRI已经成为研究人脑的重要方法.fMRI在视觉研究中的应用已经使人们对视觉系统的功能性组织有了更好的理解,并取得了很多成果.今后的研究方向是进一步探讨人脑的意识、注意、记忆等高级功能的神经机制.     

麝的系统发育学研究进展

麝Moschus spp.是亚洲地区特产野生动物,具有非常重要的经济和生态价值,为我国一级重点保护物种,已被列入CITES附录Ⅰ中.麝一直为中外学者所关注.目前,麝作为独立的科已被广泛接受,但麝与新反刍下目中其他现生类群的系统发育关系长期处于"广泛争论"状态.本文从形态学、分子生物学等特征对麝的系统发育学研究进行了简要概述,总结了麝与其他新反刍下目现生类群的系统发育关系,提出了一些尚待研究的问题,并对将来的研究工作做出展望.     

常识性: 心理学另一种文化品格

今天心理学在科学化道路上已经越走越远,渐渐远离了人类日常生活,彰显着浓郁的自然科学品性：成为心理学家孤芳自赏的一种标签。事实上,心理学不仅仅是“心理学家”的心理学,也应该是人民大众的心理学,这便是心理学另一重要品质——常识性。常识性心理学可使人的心灵活动得到素朴、直观理解,是常识心理学而非心理科学使得人们日常心理生活成为可能。毛为科技理性和逻辑语言所支配下的科学心理学抹上浓郁的文化色彩,使其流露出文化品性,也为重新理解和诠释心理学学科性质提供视角。     

Neural correlates of the contents of visual awareness in humans

The immediacy and directness of our subjective visual experience belies the complexity of the neural mechanisms involved, which remain incompletely understood. This review focuses on how the subjective contents of human visual awareness are encoded in neural activity. Empirical evidence to date suggests that no single brain area is both necessary and sufficient for consciousness. Instead, necessary and sufficient conditions appear to involve both activation of a distributed representation of the visual scene in primary visual cortex and ventral visual areas, plus parietal and frontal activity. The key empirical focus is now on characterizing qualitative differences in the type of neural activity in these areas underlying conscious and unconscious processing. To this end, recent progress in developing novel approaches to accurately decoding the contents of consciousness from brief samples of neural activity show great promise.     

The remote roots of consciousness in fruit‐fly selective attention?

A mechanistic study of consciousness need not be confined to human complexity. Other animals also display key behaviors and responses that have long been intimately tied to the measure of consciousness in humans. Among them are some very well-defined and measurable endpoints: selective attention, sleep and general anesthesia. That these three variables associated with changes in consciousness might exist even in a fruit-fly does not necessarily imply that a fly is "conscious", but it does suggest that some of the problems central to the field of consciousness studies could be investigated in a model organism such as Drosophila melanogaster. Demonstrating suppression of unattended stimuli, which is central to attention studies in humans, is now possible in Drosophila by measuring neural correlates of visual selection. By combining such studies with an eventual understanding of suppression in other arousal states in the fly, such as sleep and general anesthesia, we might be unraveling mechanisms relevant to consciousness as well.     

Does consciousness overflow cognitive access? Novel insights from the new phenomenon of attribute amnesia

The moment we open our eyes, we experience a rich and detailed visual world, but the amount of information available to report is rather limited. This dissociation relates to a major debate regarding the nature of visual consciousness. The overflow argument suggests that our conscious experience is quite rich and far beyond what can be reported, standing in sharp contrast to the nooverflow argument that visual consciousness is severely impoverished and limited to what can be reported. In this paper, we systematically reviewed existing evidence in favor of the overflow argument, including studies of several variations of the iconic memory paradigm and the divided attention paradigm, as well as studies of neural correlates of consciousness. Simultaneously,we expounded some critical objections and alternative interpretations to such evidence, as well as some opposing evidence.Finally, we introduced a series of our recent studies based on a striking phenomenon of attribute amnesia, which we believe could provide new insight into the overflow view of visual consciousness.     

An extension to the hypothesis of the asynchrony of visual consciousness

An existing hypothesis states that visual consciousness is made up of 'microconsciousnesses' occurring asynchronously in several sites of the visual system of the brain with no need for direct means of binding. We extend this hypothesis to define what qualifies a neural activity for generating an element of consciousness to distinguish it from one that does not. We argue that, for these separate neural activities to represent elements of a compound sense of consciousness, they each need the support of sites that unconsciously process an important attentional referent and that it is the commonality of such referents in differing sites which bring the microconsciousnesses together. We consider the broader implications of this extended hypothesis for other sensory modalities and mental imagery.     

In search for neurophysiological criteria of altered consciousness

Neurophysiological approaches to brain mechanisms of consciousness are discussed. The concept of spatial synchronization of nervous processes developed by M.N. Livanov is applied to neurophysiological analysis of higher brain functions. However, the spatial synchronization of brain potentials is only a condition for information processing and does not represent it as such. This imposes restrictions on conclusions about the neural mechanisms of consciousness. It is more adequate to use the concept of spatial synchronization in views of consciousness as a psychophysiological level along with sub- and superconsciousness in three-level structure of mind according to P.V. Simonov. Forms of consciousness interaction with other levels concern the problem of altered consciousness and may be reflected in various patterns of spatial organization of brain potentials.     

The interplay of attention and consciousness in visual search,attentional blink and working memory consolidation

Despite the acknowledged relationship between consciousness and attention, theories of the two have mostly been developed separately. Moreover, these theories have independently attempted to explain phenomena in which both are likely to interact, such as the attentional blink (AB) and working memory (WM) consolidation. Here, we make an effort to bridge the gap between, on the one hand, a theory of consciousness based on the notion of global workspace (GW) and, on the other, a synthesis of theories of visual attention. We offer a theory of attention and consciousness (TAC) that provides a unified neurocognitive account of several phenomena associated with visual search, AB and WM consolidation. TAC assumes multiple processing stages between early visual representation and conscious access, and extends the dynamics of the global neuronal workspace model to a visual attentional workspace (VAW). The VAW is controlled by executive routers, higher-order representations of executive operations in the GW, without the need for explicit saliency or priority maps. TAC leads to newly proposed mechanisms for illusory conjunctions, AB, inattentional blindness and WM capacity, and suggests neural correlates of phenomenal consciousness. Finally, the theory reconciles the all-or-none and graded perspectives on conscious representation.     

Neural circuit models for computations in early visual cortex

Some cortical circuit models study the mechanisms of the transforms from visual inputs to neural responses. They model neural properties such as feature tunings, pattern sensitivities, and how they depend on intracortical connections and contextual inputs. Other cortical circuit models are more concerned with computational goals of the transform from visual inputs to neural responses, or the roles of the neural responses in the visual behavior. The appropriate complexity of a cortical circuit model depends on the question asked. Modeling neural circuits of many interacting hypercolumns is a necessary challenge, which is providing insights to cortical computations, such as visual saliency computation, and linking physiology with global visual cognitive behavior such as bottom-up attentional selection.     

Catalysts for change: the cellular neurobiology of psychedelics

The resurgence of interest in the therapeutic potential of psychedelics for treating psychiatric disorders has rekindled efforts to elucidate their mechanism of action. In this Perspective, we focus on the ability of psychedelics to promote neural plasticity, postulated to be central to their therapeutic activity. We begin with a brief overview of the history and behavioral effects of the classical psychedelics. We then summarize our current understanding of the cellular and subcellular mechanisms underlying these drugs’ behavioral effects, their effects on neural plasticity, and the roles of stress and inflammation in the acute and long-term effects of psychedelics. The signaling pathways activated by psychedelics couple to numerous potential mechanisms for producing long-term structural changes in the brain, a complexity that has barely begun to be disentangled. This complexity is mirrored by that of the neural mechanisms underlying psychiatric disorders and the transformations of consciousness, mood, and behavior that psychedelics promote in health and disease. Thus, beyond changes in the brain, psychedelics catalyze changes in our understanding of the neural basis of psychiatric disorders, as well as consciousness and human behavior.     

The neural subjective frame: from bodily signals to perceptual consciousness

The report ‘I saw the stimulus’ operationally defines visual consciousness, but where does the ‘I’ come from? To account for the subjective dimension of perceptual experience, we introduce the concept of the neural subjective frame. The neural subjective frame would be based on the constantly updated neural maps of the internal state of the body and constitute a neural referential from which first person experience can be created. We propose to root the neural subjective frame in the neural representation of visceral information which is transmitted through multiple anatomical pathways to a number of target sites, including posterior insula, ventral anterior cingulate cortex, amygdala and somatosensory cortex. We review existing experimental evidence showing that the processing of external stimuli can interact with visceral function. The neural subjective frame is a low-level building block of subjective experience which is not explicitly experienced by itself which is necessary but not sufficient for perceptual experience. It could also underlie other types of subjective experiences such as self-consciousness and emotional feelings. Because the neural subjective frame is tightly linked to homeostatic regulations involved in vigilance, it could also make a link between state and content consciousness.     

Attention and awareness in stage magic: turning tricks into research

Just as vision scientists study visual art and illusions to elucidate the workings of the visual system, so too can cognitive scientists study cognitive illusions to elucidate the underpinnings of cognition. Magic shows are a manifestation of accomplished magic performers' deep intuition for and understanding of human attention and awareness. By studying magicians and their techniques, neuroscientists can learn powerful methods to manipulate attention and awareness in the laboratory. Such methods could be exploited to directly study the behavioural and neural basis of consciousness itself, for instance through the use of brain imaging and other neural recording techniques.