Similarities Between the Psychological Profiles of Complex Regional Pain Syndrome and Conversion Disorder Patients

The psychological profile of 17 Complex Regional Pain Syndrome type I (CRPS) and 20 Conversion Disorder (CD) patients were compared, using the Minnesota Multiphasic Personality Inventory (MMPI) and standardized, semistructured psychological interviews. Both groups presented abnormally high somatization scores. Low anxiety scores in both groups indicate that somatization may have served as a defense mechanism to bind anxiety. Depression was apparent in both groups, indicating that psychological distress accompany these syndromes. About one third of the participants in both groups presented comorbid Axis I disorders, mostly depression and PTSD. CRPS patients have traditionally been looked upon as suffering from mainly organic symptoms, whereas CD patients have been labeled as psychiatric patients. These results may indicate the need to reexamine the traditional classifications in respect to disorders that involve body and mind.     

Discriminating deterministic versus stochastic dynamics in neuronal activity

An approach to discriminating deterministic versus stochastic dynamics from neuronal data is presented. Direct tests for determinism are emphasized, as well as using time series with clear physical correlates measured from small ensembles of neurons. Surrogate data are used to provide null hypotheses that the dynamics in our data could be accounted for by linear stochastic systems. Algorithms are given in full, and the analysis of an experimental example is given.     

Modification of the startle reflex in a community sample: do one or two dimensions of psychopathy underlie emotional processing?

Recent research on psychopathy has begun to explore two dimensions that possibly underlie psychopathy–one related more to emotional and interpersonal traits, and another related more to antisocial behaviors. A community sample of adults was assessed for psychopathy using Hare's (1991) Psychopathy Checklist-Revised (PCL-R). Eyeblinks elicited by startle probes were recorded while participants viewed pictures of emotionally-laden stimuli. Consistent with previous research, participants scoring high on PCL-R Factor 2 (“antisocial”) showed no affective modification of startle if they also scored high on PCL-R Factor 1 (“emotional detachment”). When the factor scores were analyzed together as continuous variables in a regression analysis, however, affective modification of startle was negatively related to Factor 1 but positively related to Factor 2. The results thus provide further support for a two-factor model of psychopathy.     

Emotional Responses to Pictures of Oneself in Healthy College Age Females

Emotional responses related to self-perceptions were investigated in healthy college-aged females using a picture-viewing paradigm that consisted of four categories of pictures (pleasant, neutral, unpleasant, and full body pictures of themselves). The startle eye-blink reflex, facial EMG, and self-reported valence, arousal, and dominance measures were recorded for each picture. Startle reflex and facial EMG measures exhibited decreased activation for self-pictures compared to the other affective categories. Self-reports indicated self-pictures were rated as moderately pleasant, low arousing, and moderately dominant relative to the other affective picture categories. The findings of reduced startle blink reflex coupled with decreased activation for all facial EMG measures and the moderate self-report ratings suggest increased attentional processing for self-pictures. These findings provide an understanding of emotional responses to self-perceptions in healthy young females.     

背景性渴求与事件性渴求:区分心理渴求对尼古丁成瘾的不同作用路径

大量研究发现心理渴求机制的紊乱是尼古丁成瘾的核心机制之一。线索暴露是探索心理渴求与尼古丁成瘾关系的重要研究范式。但最近研究者提出该范式较难区分事件性渴求与背景性渴求,导致无法清楚定位渴求在尼古丁成瘾中扮演的角色。通过对以往文献的回顾,对不同成瘾概念、作用机制和生理基础进行对比分析,认为事件性渴求与背景性渴求两者在维持成瘾行为上的确存在不同的作用路径。未来研究应改进实验范式,分别探讨两种心理渴求与尼古丁成瘾的内在联系,完善心理渴求与尼古丁成瘾的关系模型,为尼古丁成瘾的治疗和干预等方法提供一定的理论依据。     

Habituation of the orienting reflex and the development of Preliminary Process Theory

The orienting reflex (OR), elicited by an innocuous stimulus, can be regarded as a model of the organism’s interaction with its environment, and has been described as the unit of attentional processing. A major determinant of the OR is the novelty of the eliciting stimulus, generally operationalised in terms of its reduction with stimulus repetition, the effects of which are commonly described in habituation terms. This paper provides an overview of a research programme, spanning more than 30 years, investigating psychophysiological aspects of the OR in humans. The major complication in this research is that the numerous physiological measures used as dependent variables in the OR context fail to jointly covary with stimulus parameters. This has led to the development of the Preliminary Process Theory (PPT) of the OR to accommodate the complexity of the observed stimulus–response patterns. PPT is largely grounded in autonomic measures, and current work is attempting to integrate electroencephalographic measures, particularly components in the event-related brain potentials reflecting aspects of stimulus processing. The emphasis in the current presentation is on the use of the defining criteria of the habituation phenomenon, and Groves and Thompson’s Dual-process Theory, in the development of PPT.     

Time and direction preparation of the long latency stretch reflex

This study investigated time and direction preparation of motor response to force load while intending to maintain the finger at the initial neutral position. Force load extending or flexing the index finger was given while healthy humans intended to maintain the index finger at the initial neutral position. Electromyographic activity was recorded from the first dorsal interosseous muscle. A precue with or without advanced information regarding the direction of the forthcoming force load was given 1000 ms before force load. Trials without the precue were inserted between the precued trials. A long latency stretch reflex was elicited by force load regardless of its direction, indicating that the long latency stretch reflex is elicited not only by muscle stretch afferents, but also by direction-insensitive sensations. Time preparation of motor response to either direction of force load enhanced the long latency stretch reflex, indicating that time preparation is not mediated by afferent discharge of muscle stretch. Direction preparation enhanced the long latency stretch reflex and increased corticospinal excitability 0–20 ms after force load when force load was given in the direction stretching the muscle. These enhancements must be induced by preset of the afferent pathway mediating segmental stretch reflex.     

Differences in performance on a reversal learning test and division of labor in honey bee colonies

We studied the association between honey bee (Apis mellifera) division of labor and performance on an olfactory reversal-learning test. Manipulations of colony age structure and flight experience were used to test whether differences in performance are associated with age, current behavioral state, or flight experience. Nurse bees showed significantly faster rates of extinction to a learned odor than did foragers. This difference was associated primarily with differences in behavioral state, rather than age; it was seen when comparing nurses and foragers from typical colonies and normal-age nurses and precocious foragers from single-cohort colonies. Differences in extinction rate were not related to differences in flight experience; there was no difference between foragers and foraging-age bees denied flight experience. These results suggest that changes in learning and memory occur in association with division of labor. We speculate on the possible functional significance of the difference in extinction rate between nurses and foragers. Received: 15 January 2000 / Accepted: 22 August 2000