Neurophysiological correlates of response production and inhibition in alcoholics

Scalp recordings of the P300 component of the event-related potential were made from a group of medication-free, chronic male alcoholics and a control group, participating in a visual Go/No Go reaction time paradigm. Subjects were presented with large and small forms of the letters T and V. The large forms (Go stimuli) required a button press with either the left or right hand, whereas the small forms (NO Go stimuli) required response inhibition. Recordings were made from 31 electrodes that, for statistical analyses, were grouped into five regions: frontal, central, parietal, occipital, and temporal. The results indicated that, in each of the five regions, both Go and NO Go response amplitudes were larger in the controls than in the alcoholics. No group differences in latency were observed in any region. Surface energy (Wang et al., Brain Topogr. 6:193-202, 1994) magnitudes paralleled P300 amplitudes and in the controls, compared with the alcoholics, were larger during both Go and No Go trials. Our findings suggest that abstinent, chronic alcoholics differ electro-physiologically from control individuals. These differences are manifested as widespread reductions in P300 amplitudes during the performance of a simple information processing paradigm. The reduced amplitudes may reflect a deficiency in an inhibitory mechanism proposed to underlie P300 generation.     

Psychobiology of novelty seeking and drug seeking behavior

There is considerable evidence that high novelty seekers are at increased risk for using drugs of abuse relative to low novelty seekers. This review examines the potential biological mechanism that may help explain the relationship between novelty seeking and drug seeking behavior. Evidence is summarized to suggest that exposure to novelty activates, at least in part, the same neural substrate that mediates the rewarding effects of drugs of abuse. It is argued that individual differences in response to novelty and drugs may relate to individual differences in the mesolimbic dopamine (DA) system of the brain. Individual differences in both novelty seeking and drug seeking behavior, while under some degree of genetic control, appear to be modifiable by early development experiences and this modification may relate to alterations in activity of the mesolimbic DA system. Within the context of this biological formulation, implications for the prevention and treatment of drug abuse are discussed.     

Event-related potentials during visual selective attention in children of alcoholics

Event-related potentials were recorded from 7- to 18-year-old children of alcoholics (COAs, n = 50) and age- and sex-matched control children (n = 50) while they performed a visual selective attention task. The task was to attend selectively to stimuli with a specified color (red or blue) in an attempt to detect the occurrence of target stimuli. COAs manifested a smaller P3b amplitude to attended-target stimuli over the parietal and occipital scalp than did the controls. A more specific analysis indicated that both the attentional relevance and the target properties of the eliciting stimulus determined the observed P3b amplitude differences between COAs and controls. In contrast, no significant group differences were observed in attention-related earlier occurring event-related potential components, referred to as frontal selection positivity, selection negativity, and N2b. These results represent neurophysiological evidence that COAs suffer from deficits at a late (semantic) level of visual selective information processing that are unlikely a consequence of deficits at earlier (sensory) levels of selective processing. The findings support the notion that a reduced visual P3b amplitude in COAs represents a high-level processing dysfunction indicating their increased vulnerability to alcoholism.     

Event-related potential correlates of linguistic information processing in schizophrenics

Event-related potentials (ERPs) were recorded from adult schizophrenics and age- and education-matched normal controls during performance of an idiom recognition task involving judgments of the meaningfulness of idiomatic, literal, and nonsense phrases. Schizophrenics produced more errors and had prolonged reaction times while attempting to correctly differentiate meaningful from meaningless phrases. An ERP correlate of that deficit was a larger than normal N400 to idioms and literals, with no difference in N400 amplitude to nonsense phrases. This result was interpreted as evidence that the influence of the linguistic context provided by the first word of two-word idiomatic and literal phrases is reduced in schizophrenia. Schizophrenics also showed reduced amplitude P300.     

Relationships between global and specified measures of novelty seeking.

Constructed 5 specified rational scales, 4 coordinated with 4 separate forms of the tendency toward novelty seeking, and 1 coordinated with desire for novelty to demonstrate the lack of comprehensive and representative coverage of the novelty domain by global self-report measures. Ss were 70 airmen. Results indicate that the 5 specified scales tend to be more homogeneous than 4 published measures of novelty or change to which they were compared. The specified scales were typically well differentiated, in contrast to the global measures which correlated substantially with each other and with 1 specified scale. The global measures examined do not appear to measure the cognitive and introceptive aspects of novelty experiencing or the desire or motivation for new experience. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event-related potential indicators of text integration across sentence boundaries.

An event-related potentials (ERPs) study examined word-to-text integration processes across sentence boundaries. In a two-sentence passage, the accessibility of a referent for the first content word of the second sentence (the target word) was varied by the wording of the first sentence in one of the following ways: lexically (explicitly using a form of the target word); conceptually (using a paraphrase of the target word), and situationally (encouraging an inference concerning the referent of the target word). A baseline condition had no coreference between the two sentences. ERP results on the target word indicated multiple effects related to word identification and word-to-referent mapping processes. Both the explicit and paraphrase conditions, but not the inference condition, showed a reduced N400 relative to the baseline condition, consistent with immediate integration by lexico-semantic processes. A 300-ms effect (P300) was found in the paraphrase condition. The results were consistent with an immediate integration hypothesis and furthermore differentiated a lexical (N200), a conceptual (P300), and a situational (N400) component for this integration. The conceptual basis appears not to extend to predictive inferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of stimulus novelty on stimulation seeking in antisocial and neurotic children.

Compared the effects of the relative novelty of stimuli on (a) level of attention and (b) rate of habituation of looking responses in antisocial and neurotic children. 18 male 8–13 yr olds viewed, at their preferred pace, 2 sets of photographic slides. The relatively novel set contained slides of diverse and constantly changing subject matter, whereas a contrasting set consisted of repetitious views of a few modern concrete buildings. Increasing the stimulus novelty resulted in increases of attention for both types of Ss but in very different ways. Neurotics were initially equally attentive to both sets of stimuli, but their attention was more highly sustained and even increased with time under conditions of relative novelty. Antisocial Ss also displayed higher initial attention to the novel stimuli than to the repetitive stimuli, but in contrast to neurotics they habituated rapidly to both sets. Treatment implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in the correlates of stimulus seeking.

Conducted 5 experiments to correlate Zuckerman, Kolin, Price, and Zoob's Sensation Seeking Scale (SSS) with other variables, e.g., scores on the Rokeach Dogmatism Scale. Ss included 518 college and high school students of both sexes and a sample of their parents (n = 341), 40 male general psychiatric patients, and 62 male alcoholic patients. Results were analyzed in terms of differences in the correlates for the total sample by sex, and differences in SSS scores for parents and their children. In males, the SSS was positively related to academic aptitude and liberal sexual attitudes, and was negatively related to authoritarianism, dogmatism, and passive food preferences. In females, the SSS was positively related to liberal sexual attitudes and negatively related to passive food preferences and to an insignificant degree to authoritarianism. SSS scores of male and female high school students showed a modest tendency to resemble those of their parents. (26 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Previous experience affects subsequent anxiety-like responses in rats bred for novelty seeking.

Novelty-seeking behavior in rats is deemed to model sensation seeking in humans, a personality trait related to some psychiatric conditions, including substance abuse. Animals characterized based on their locomotor response to novelty, namely high and low responders (HRs and LRs, respectively), show differences in anxiety and drug-taking behaviors. This study evaluates the effect of anxiety-provoking situations on subsequent behaviors in these endophenotypes. Selectively bred HR and LR rats were submitted to blocks of tests consisting of two-trial light- dark (LD) and two-trial elevated plus maze (EPM) tests arranged in counterbalanced, alternating order. No differences in anxiety-like behaviors were found in HR-bred and LR-bred rats in either LD trial, regardless of the test order. Repeated exposure to the EPM test, however, resulted in enhanced behavioral response under different test orders as a function of endophenotype. Compared with HR-bred animals, LR-bred animals exhibited increased anxiety on reexposure to EPM but only if both trials were preceded by an LD test session. The emotional responses in HR-bred and LR-bred rats reported here may reflect different degrees of adaptive processing regulated by both genetic and environmental factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chronological age differences in MMPI scores of male chronic alcoholics seeking treatment.

M. Gynther's (1979) general hypothesis that older Ss self-report better adjustment on the MMPI than do younger Ss was tested among 616 male chronic alcoholics classified into 5 age groups: 30 or younger, 31–40, 41–50, 51–60, and 61 or older. Multivariate and univariate analyses of variance and covariance supported Gynther's general hypothesis as well as 3 specific corollary hypotheses predicting that older alcoholics, relative to younger alcoholics, are lower in impulsivity-control difficulties and higher in health concerns, but are not different in social introversion. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elevated novelty seeking and peculiar d-amphetamine sensitization in periadolescent mice compared with adult mice

Novelty seeking as well as amphetamine sensitization were studied in adult (postnatal day "PND" > 60) and periadolescent (PND 3343) mice treated with saline or amphetamine (2 or 10 mg/kg once per day) for 3 days in a familiar environment. After a 48-hr wash-out period, mice were challenged with either saline or amphetamine (2 mg/kg) in the same environment. When given a choice, animals showed a preference for a novel environment, an effect more marked in periadolescents. Acute amphetamine strongly increased novelty seeking in adults, whereas it had an opposite effect in periadolescents. Adult mice in the chronic amphetamine 2 group showed a conditioned preference for the drug-paired compartment, whereas an aversion characterized adult mice in the amphetamine 10 group. Periadolescents in the latter group exhibited a greater sensitization of the locomotor response, but did not show the compulsive licking typical of adults. This appears to be a useful model to study psychobiological risk factors involved in vulnerability to addiction during human adolescence.     

Event-related potentials as indicators of repetition priming in young and older adults: amplitude, duration, and scalp distribution

Event-related brain potentials (ERPs) were recorded in young and older adults in an indirect repetition priming paradigm. Compared with the young adults, the older adults' ERP repetition effect was larger and of longer duration, due entirely to greater amplitude elicited by the repeated item. These data suggest that, although indirect memory (as indexed by a robust ERP repetition effect) appeared to be intact in the older adult, the possibility exists for qualitative age-related differences consistent with inefficient and/or additional processing of the repeated item.     

Event-related potentials elicited by infrequent non-target stimuli in young children of alcoholics: family history and gender differences

The treatment of cognitive communicative impairments that occur due to traumatic brain injury is a relatively new field. There is a need for more empirical evidence supporting the efficacy of cognitive rehabilitation. Fortunately, the number of studies in this area have continued to grow over the past few years. The purpose of this article is to provide current information regarding the assessment of functional outcomes after traumatic brain injury using the theoretical framework of the International Classification of Impairments, Disabilities, and Handicaps (ICIDH), which was developed by the World Health Organization (WHO).     

Demographic correlates of attitude toward seeking professional psychological help.

Found that help-seeking orientation was unrelated to social class of origin (based on father's social position) in a total sample of student Ss (N = 989) and for high school Ss and college freshmen considered separately. Jewish Ss tended to express more positive attitudes than Catholics or Protestants. Variables pertinent to academic life, e.g., educational level and scholastic major, significantly differentiated attitudes toward seeking professional aid. Correspondence of attitude to education level was independent of age. Thus, the less favorable outlooks of students with less education are not attributable to proximity to parental values or to greater cynicism among newer students. Findings suggest that attitudes toward psychologists and psychiatrists as help sources are not as closely tied to socioeconomic class as has been indicated in earlier sociological studies. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol use, expectancies, and sexual sensation seeking as correlates of HIV risk behavior in heterosexual young adults.

Most theoretical models of HIV risk behavior have not considered the role of personality factors, and few studies have examined mechanisms accounting for dispositional influences on sexual risk taking. This study elaborated on a conceptual model emphasizing sexual sensation seeking, alcohol expectancies, and drinking before sex as key predictors of HIV risk (S. C. Kalichman, L. Tannenbaum, & D. Nachimson, 1998). Multiple groups structural equation modeling was used to determine whether gender moderated relationships among these variables in a sample of 611 heterosexual, young adult drinkers (49% women, 76% Caucasian, mean age = 25 years). The model provided an excellent fit to the data, and gender differences were not substantiated. Sexual sensation seeking predicted HIV risk directly as well as indirectly via sex-related alcohol expectancies and drinking in sexual contexts. Findings suggest that expectancies and drinking before sex represent proximal mechanisms through which dispositional factors influence sexual risk outcomes. Moreover, these relationships appear to be similar in men and women. Interventions could benefit from targeting alcohol expectancies and drinking before sex in individuals with a dispositional tendency toward sexual risk taking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioned suppression of an operant response using d-amphetamine as the conditioned stimulus

The dimer of fragment D is isolated preparatively by CM-cellulose chromatography (in neutral medium) from dialyzed tryptic hydrolyzate of stabilized fibrin. Contrary to the fragment D monomer obtained from fibrinogen under the same conditions, the dimer itself cannot inhibit polymerization of monomeric fibrin. However with the presence of monomer D in the amount sufficient for essential inhibition of the fibrin polymerization the addition of dimer D produces the further delay in polymerization. Under these conditions dimer D is highly effective inhibitor if its amount is not too little, as its small doses are not effective.     

Dexamethasone suppression and self-reinforcement correlates of clinical depression.

Neuroendocrine dysfunction and self-reinforcement deficits were evaluated in 45 individuals exhibiting symptoms of major depression. The dexamethasone suppression test (DST), Beck Depression Inventory (BDI), and Frequency of Self-Reinforcement Questionnaire (FSRQ) were administered to subjects who also were participating in a comparative antidepressant drug study. Subjects with low rates of self-reinforcement tended to exhibit normal DST responses, whereas high self-reinforcement could not be characterized as being significantly more or less dysfunctional on the DST. Only one third of this sample of depressives evidenced abnormal DSTs, which suggests that in these cases of depression with normal neuroendocrine functioning, a deficit in self-reinforcement could be related to depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temperament and novelty seeking in adolescent substance use: convergence of dimensions of temperament with constructs from Cloninger's theory

This study investigated the convergence of temperament dimensions with constructs from C. R. Cloninger's (1987a) theory using data from a sample of 949 adolescents (M age = 13.6 years). Substantial convergence was found, and both types of constructs were related in predicted ways to self-regulation variables and adolescent substance use. Structural modeling procedures tested a mediational model for substance use; results showed mediation through self-control, academic competence, negative life events, and deviant peer affiliations. Interactions indicated that substance use could be predicted from a balance of systems for good control and poor control. Poor self-control was present for dimensions implicated in both externalizing and internalizing disorders. Results are discussed with reference to self-regulation models of substance use and the comorbidity of substance abuse and mental disorder.     

Association between dopamine D4 receptor (D4DR) exon III polymorphism and novelty seeking in Japanese subjects

Only five cases of paraganglioma of the prostate have been reported hitherto. The tumours may be functional (phaeochromocytomas) or non-functional and benign or malignant. We present a sixth case--a non-functional, benign paraganglioma of the prostate--with a review of the literature.     

Individual differences in response to novelty, amphetamine-induced activity and drug discrimination in rats

Individual group, and ethnic differences in behavior have been an object of long, continuing, and contentious interest, both in the sciences and in popular culture. For well over 2,000 years, psychological traits, particularly those described as 'intelligence', have generally been considered the major factors in fitness in humans. After reviewing contemporary scientific thinking on intelligence, the psychometric methods used for the construction of psychological tests are presented and examined in the context of natural selection and metric characters. There are essential differences between the disciplines of genetics and of psychology such that the concepts of the two are more divergent than might superficially appear to be the case. The analysis leads to the conclusion that standard psychometric methodology cannot yield tests appropriate for measurement of evolutionary fitness characters.