Temporal kinetics of prefrontal modulation of the extrastriate cortex during visual attention

Single-unit, event-related potential (ERP), and neuroimaging studies have implicated the prefrontal cortex (PFC) in top-down control of attention and working memory. We conducted an experiment in patients with unilateral PFC damage (n=8) to assess the temporal kinetics of PFC-extrastriate interactions during visual attention. Subjects alternated attention between the left and the right hemifields in successive runs while they detected target stimuli embedded in streams of repetitive task-irrelevant stimuli (standards). The design enabled us to examine tonic (spatial selection) and phasic (feature selection) PFC-extrastriate interactions. PFC damage impaired performance in the visual field contralateral to lesions, as manifested by both larger reaction times and error rates. Assessment of the extrastriate P1 ERP revealed that the PFC exerts a tonic (spatial selection) excitatory input to the ipsilateral extrastriate cortex as early as 100 msec post stimulus delivery. The PFC exerts a second phasic (feature selection) excitatory extrastriate modulation from 180 to 300 msec, as evidenced by reductions in selection negativity after damage. Finally, reductions of the N2 ERP to target stimuli supports the notion that the PFC exerts a third phasic (target selection) signal necessary for successful template matching during postselection analysis of target features. The results provide electrophysiological evidence of three distinct tonic and phasic PFC inputs to the extrastriate cortex in the initial few hundred milliseconds of stimulus processing. Damage to this network appears to underlie the pervasive deficits in attention observed in patients with prefrontal lesions.     

The nature of social and personality psychology as reflected in JPSP, 1965-2000

A bibliometric analysis of the first 36 years (1965-2000) of the Journal of Personality and Social Psychology (JPSP) is presented. The authors analyzed the structure of JPSP on the basis of contents and other aspects related to productivity, such as growth in the number of articles and authors, and "invisible colleges." In 2001, JPSP articles were cited over 23,000 times. An increasing number of older, classic articles are cited, suggesting that there are an accumulating number of citations whose influence endures over time. JPSP articles have grown in length, number of studies included, number of references, and number of authors and have become more international with an increasing proportion of authors from outside the United States. The pattern of findings suggests an increasingly complex and mature science.     

Differential effects of forward or simultaneous conditioned stimulus-unconditioned stimulus intervals on the defensive behavior system of the Norway rat (Rattus norvegicus)

To test several predictions derived from a behavior-systems approach, the authors assessed Pavlovian fear conditioning in rats after 30 trials of forward, simultaneous, or unpaired training. Direct evidence of conditioned fear was collected through observation of flight and freezing reactions during presentations of the conditioned stimulus (CS) alone. The authors also tested the CS's potential to reinforce an instrumental escape response in an escape-from-fear paradigm. On the one hand, rats that received forward training showed conditioned freezing, but no conditioned flight was observed. On the other hand, rats that received simultaneous training showed conditioned flight, but no conditioned freezing was observed. Rats that received either forward or simultaneous pairings showed instrumental learning of the escape-from-fear response. Implications for several theories of Pavlovian conditioning are discussed.     

Einstein's theory of theories and types of theoretical explanation

In this paper I draw on Einstein's distinction between “principle” and “constructive” theories to isolate two levels of physical theory that can be found in both classical and (special) relativistic physics. I then argue that when we focus on theoretical explanations in physics, i.e. explanations of physical laws, the two leading views on explanation, Salmon's “bottom‐up” view and Kitcher's “top‐down” view, accurately describe theoretical explanations for a given level of theory. I arrive at this conclusion through an analysis of explanations of mass—energy equivalence in special relativity.     

Acoustic markers associated with impairment in language processing in Alzheimer's Disease

This study broaches in a novel way the analysis of cognitive impairment characteristic of the early stages of Alzheimer's Disease (AD). Specifically, we attempt to determine the acoustic speech parameters that are sensitive to the onset of the disease, and their association with the language deficit characteristic of AD. Speech analysis was carried out on 21 elderly patients with AD using Praat software, which analyzes the acoustic components of speech. The data obtained were subjected to stepwise regression, using the overall scores obtained in the test as the criterion variable, and the scores on the frequency, amplitude and periodicity variables as predictors of performance. We found that the percentage of voiceless segments explains a significant portion of the variance in the overall scores obtained in the neuropsychological test. This component seems to be related mainly to the patient's ability in phonological fluency. This finding could permit the creation of a diagnostic test for AD through analysis of the acoustic speech parameters at very low cost in terms of both time and resources.     

Morningness-eveningness and health-related quality of life among adolescents

Accumulating evidence suggests that evening-type adolescents are exposed to a number of determinants that might have a negative impact on their health condition. Given that few studies have investigated the association between chronotype and quality of life measures in large samples of adolescents, the aim of this study was to assess the relationship between morningness-eveningness and health-related quality of life among 1600 adolescents (aged 12-16 years). Adolescents completed the Ve?u et Santé Per?ue de L'adolescent (VSP-A) and the Morningness-Eveningness Scale for Children (MESC). Girls and older adolescents reported worse health indicators and were more evening oriented. Evening-type adolescents obtained lower scores on vitality, physical and psychological well-being, body image, relations with parents, relations with teachers, school work and global health scale.     

Sociodemographic, clinical and outcome differences among anxiety disorders

The aims of this paper are to analyze differences in sociodemographic and clinical characteristics among the various anxiety disorders treated in a Psychology Clinic, and the results of treatment in each anxiety disorder. Data from 282 patients of University Psychology Clinic at the Complutense University of Madrid, who had at least one diagnosis of anxiety according to DMS-IV-TR criteria, were analyzed. The most frequent anxiety disorders were nonspecific anxiety disorder (19.1%) and social phobia (18.8%). Significant differences were observed according to sex (in all disorders, the percentage of women was significantly higher than that of men, except for obsessive-compulsive disorder). Unspecific anxiety disorder required a smaller number of assessment and treatment sessions, whereas obsessive-compulsive disorder required a greater number of sessions. There were no significant differences between the percentage of patients who completed treatment and dropout rates in specific phobia, general anxiety disorder and obsessive-compulsive disorder. Differences between epidemiological and clinical data are discussed.     

Factor models of the Beck Depression Inventory-II. Validation with coronary patients and a critique of Ward's model

The objective of this study was to validate in a sample of 205 coronary patients a factor model for the BDI-II, especially a model that would allow for modeling of depressive symptoms after explicitly removing bias related to somatic symptoms of depression that would overlap those of heart disease. Exploratory and confirmatory factor analyses for ordinal data were conducted. A one-factor model, six correlated two-factor models and, derivatives thereof, seven models with a single General Depression factor and two uncorrelated factors, were analyzed. Exploratory analysis extracted two factors, Somatic-affective and Cognitive. Confirmatory factor analyses showed the worst fit for the one-factor model. Two-factor models were surpassed in goodness of fit by the models of general-factor and group factors. Among these, the General, Somatic-affective and Cognitive (G-Sa-C) model of Beck with students is noteworthy. The reduced General, Somatic and Cognitive (G-S-C) model of Ward showed the worst goodness of fit. Our model surpasses the cutoff criteria of all fit indexes. We conclude that the inclusion of a general-factor and group factors in all the models surpasses the results of G-S-C model and, therefore, questions it. The G-Sa-C model is strengthened.     

Approaching stimuli bias attention in numerical space

Increasing evidence suggests that common mechanisms underlie the direction of attention in physical space and numerical space, along the mental number line. The small leftward bias (pseudoneglect) found on paper-and-pencil line bisection is also observed when participants 'bisect' number pairs, estimating (without calculating) the number midway between two others. Here we investigated the effect of stimulus motion on attention in numerical space. A two-frame apparent motion paradigm manipulating stimulus size was used to produce the impression that pairs of numbers were approaching (size increase from first to second frame), receding (size decrease), or not moving (no size change). The magnitude of pseudoneglect increased for approaching numbers, even when the final stimulus size was held constant. This result is consistent with previous findings that pseudoneglect in numerical space (as in physical space) increases as stimuli are brought closer to the participant. It also suggests that the perception of stimulus motion modulates attention over the mental number line and provides further support for a connection between the neural representations of physical space and number.