Temporal binding, binocular rivalry, and consciousness.

Cognitive functions like perception, memory, language, or consciousness are based on highly parallel and distributed information processing by the brain. One of the major unresolved questions is how information can be integrated and how coherent representational states can be established in the distributed neuronal systems subserving these functions. It has been suggested that this so-called "binding problem" may be solved in the temporal domain. The hypothesis is that synchronization of neuronal discharges can serve for the integration of distributed neurons into cell assemblies and that this process may underlie the selection of perceptually and behaviorally relevant information. As we intend to show here, this temporal binding hypothesis has implications for the search of the neural correlate of consciousness. We review experimental results, mainly obtained in the visual system, which support the notion of temporal binding. In particular, we discuss recent experiments on the neural mechanisms of binocular rivalry which suggest that appropriate synchronization among cortical neurons may be one of the necessary conditions for the buildup of perceptual states and awareness of sensory stimuli.     

The Application of Cognitive Therapy for Command Hallucinations

It has become increasingly recognized that cognitive therapy (CT) is an effective treatment for the positive symptoms of schizophrenia yet there are few cognitive therapists in North America who are specialized to work with this patient population. There is a need for further dissemination of CT for schizophrenia in order to increase its availability. A first step in dissemination is to become familiar with the cognitive theory and therapy model, as applied to schizophrenia. The purpose of the present paper is to demonstrate the applicability of CT for psychosis, using the example of command hallucinations. First, we summarize the cognitive theory of command hallucinations and present the stages of CT, using the example of “Joe,” a 24-year-old male with schizophrenia. The paper concludes with practical suggestions of how to enhance the effectiveness of CT for command hallucinations.     

The role of working memory capacity and knowledge access in text inference processing

Individual differences in drawing bridging inferences during text comprehension were examined. We measured reader differences in working memory capacity, using the reading span task, and in access to relevant knowledge, using Potts and Peterson’s (1985) integration task. The dependent measure of greatest concern was answer time about facts posited to validate the bridging inference. Reading span and access were negligibly correlated, an outcome that supports their independence. Answer times were lower both for high reading span and high-access readers. In addition, readers who were either high on both reader traits or low on both traits exhibited qualitatively different inference effects from the typical pattern. It is proposed that knowledge access during comprehension is facilitated by the extraction of integrated situation models from text and that it is individuals with efficient reading processes who can construct these models.     

Neuronal assemblies: necessity, signature and detectability

The ease with which highly developed brains can generate representations of a virtually unlimited diversity of perceptual objects indicates that they have developed very efficient mechanisms to analyse and represent relations among incoming signals. Here, we propose that two complementary strategies are applied to cope with these combinatorial problems. First, elementary relations are represented by the tuned responses of individual neurons that acquire their specific response properties (feature selectivity) through appropriate convergence of input connections in hierarchically structured feed-forward architectures. Second, complex relations that cannot be represented economically by the responses of individual neurons are represented by assemblies of cells that are generated by dynamic association of individual, featureselective cells. The signature identifying the responses of an assembly as components of a coherent code is thought to be the synchronicity of the respective discharges. The compatibility of this hypothesis is examined in the context of recent data on the dynamics of synchronization phenomena, the dependence of synchronization on central states and the relations between the synchronization behaviour of neurons and perception.     

In search of common foundations for cortical computation

It is worthwhile to search for forms of coding, processing, and learning common to various cortical regions and cognitive functions. Local cortical processors may coordinate their activity by maximizing the transmission of information coherently related to the context in which it occurs, thus forming synchronized population codes. This coordination involves contextual field (CF) connections that link processors within and between cortical regions. The effects of CF connections are distinguished from those mediating receptive field (RF) input; it is shown how CFs can guide both learning and processing without becoming confused with the transmission of RF information. Simulations explore the capabilities of networks built from local processors with both RF and CF connections. Physiological evidence for synchronization, CFs, and plasticity of the RF and CF connections is described. Coordination via CFs is related to perceptual grouping, the effects of context on contrast sensitivity, amblyopia, implicit influences of color in achromotopsia, object and word perception, and the discovery of distal environmental variables and their interactions through self-organization. Cortical computation could thus involve the flexible evaluation of relations between input signals by locally specialized but adaptive processors whose activity is dynamically associated and coordinated within and between regions through specialized contextual connections.     

生物化学测定用于紧张状态的评定和处理

本文以实例说明在工业紧张状态的评定中问卷法可能是一不可靠的方法。提出了应用内分泌(激素)测定作为替代方法的理由。以实例表明在实验室研究中人为地造成紧张状态时尿内肾上腺素、去甲肾上腺素、多巴胺和皮质醇水平增高。根据我们实验室的资料表明在心理紧张和体力活动时血液动力测量和激素间相关是不同的,这证实了下述假设:“格斗—逃跑”激素反应对应付心理紧张来说是不适宜的。在欧洲和澳大利亚的工业中进行的流行病学研究表明在某些职业与心血管疾病发病率之间的相关。从实验室研究所得资料证明,由于紧张状态引起激素改变而导致心脏病的因果关系。拉屈别大学研究组的研究表明了在服装工业中在自动化机器和手工操作机器工人之间肾上腺素和去甲肾上腺素水平的差异。其他由现场研究得来的资料如在锯木厂、在领港员和邮政工人中的研究也表明了与职业有关的激素改变。在进一步发展应用激素水平作为应激指标中,根据对警察和经理的紧张状态处理的研究结果表明,处理结束时接受紧张状态处理方案的人尿内激素水平比未接受处理的对照组低。结论是:生化测量在预测与紧张状态有关的疾病的发生中是更为可靠和有效的,它们的应用对澳大利亚工会和厂方来说也是可以接受的。     

Methodology for a prospective study of suitability for psychoanalysis: the role of psychological tests.

A methodology for the use of psychological tests in the evaluation for suitability for psychoanalysis is described. Four variables--Reality Testing, Level and Quality of Object Relations, Affect Availability and Tolerance, and Motivation--were chosen for study and are discussed in detail. Data indicating a high degree of reliability between raters are presented.     

Effects of Control on the Stress Reactions of Commuters1

The effects of morning, rush hour commuting were examined in a quasi-experimental field study involving government-employed commuters (single and carpool drivers). Commuting stress was measured as a response to variations in how difficult it was for commuters to move from home to work. The mediation of these effects by two sources of control in the commuting situation also were assessed. Control was operationalized as control over the internal environment of the car (single versus carpool driver) and choice over routes taken to get to work. Among commuters with a high impedance route, driving to work was associated with significant increases in systolic and diastolic blood pressure and decreases in behavioral performance. The stress of commuting under high impedance conditions was reduced for single drivers relative to carpoolers. Under similar conditions of high impedance, however, having the option to select more than one route to get to work seemed to be more stressful than having only one route. The practical implications of these results are discussed.