Effects of spatial and symbolic precues on localization performance

One of the fundamental properties of spatial vision is the ability to localize objects in space. According to a recent proposal, accurate localization performance involves the operation of two systems: the attention system and the eye movement system. Upon stimulus presentation, attention is shifted to the target area: this provides coarse location information. Subsequently, a saccadic eye movement is executed: this provides fine location information. In this study we tested predictions derived from this model concerning the effects of precue information on localization performance. In a series of five experiments we manipulated duration of precue (71, 400, and 1,000 ms) and type of precue (spatial versus symbolic). Results showed that very short duration (i.e., 71 ms) spatial precues improved localization performance whereas very short duration symbolic precues did not. In contrast, the 1,000 ms duration precue condition showed similar amounts of precuing benefit for the spatial and symbolic precues. This pattern of differential precuing effects corroborated the two-process model of localization performance. Received: 24 June 1999 / Accepted: 28 January 2000     

A study of temperament and personality in anorexia and bulimia nervosa

Although temperament and personality traits could influence the development and course of eating disorders, only a few studies examined the similarities and differences in personality between anorexia and bulimia nervosa. We compared 72 patients with DSM-IV eating disorders and 30 healthy controls. Dimensions of personality and personality disorders were evaluated with the Eysenck's EPQ, Cloninger's TCI, and the SCID-II questionnaires. The rates of impulsivity and clinical features were evaluated using specific rating scales. A comorbid personality disorder was found in 61.8% of patients with eating disorder. Avoidant personality disorder appeared was relatively common in anorexia nervosa restricting type; borderline personality disorder was most frequent in bulimia nervosa and the binge eating-purging type of anorexia nervosa. From a dimensional perspective, anorexic patients presented high scores in the dimension of persistence. Higher harm avoidance and impulsivity was found in bulimic patients. The overall eating disorders group presented high scores in neuroticism and low scores in self-directedness. Eating disorder patients have heterogeneous features of temperament and personality traits. Cluster C personality disorders seem more common in anorexia nervosa restricting type and impulsive personality features are associated with bulimic symptoms. Impulsivity seems to be a key aspect of temperament of bulimic patients, whereas anorexic symptoms are linked to persistent temperament traits.     

Stroop interference and negative priming: Problems with inferences from null results

The Stroop color-naming effect has often been taken as evidence for the automaticity of word processing (MacLeod, 1991). Recently, Besner, Stolz, and Boutilier (1997) reported that coloring a single letter instead of the whole word eliminated the Stroop effect. From this finding, they concluded that word processing could not be purely automatic, since it can be prevented. We asked whether the elimination of the Stroop effect is sufficient evidence for concluding that the word is not processed. Combining Besner et al.’s manipulation with a negative-priming procedure, we found intact negative priming from the prime color word in the absence of a Stroop effect. This result clearly indicates that the meaning of the prime word was processed. The findings highlight the importance of using converging methods to evaluate lack of processing.     

Differential fear conditioning induces reciprocal changes in the sensory responses of lateral amygdala neurons to the CS(+) and CS(-)

In classical fear conditioning, a neutral sensory stimulus (CS) acquires the ability to elicit fear responses after pairing to a noxious unconditioned stimulus (US). As amygdala lesions prevent the acquisition of fear responses and the lateral amygdaloid (LA) nucleus is the main input station of the amygdala for auditory afferents, the effect of auditory fear conditioning on the sensory responsiveness of LA neurons has been examined. Although conditioning was shown to increase CS-evoked LA responses, the specificity of the changes in responsiveness was not tested. Because conditioning might induce nonspecific increases in LA responses to auditory afferents, we re-examined this issue in conscious, head-restrained cats using a differential conditioning paradigm where only one of two tones (CS(+) but not CS(-)) was paired to the US. Differential conditioning increased unit and field responses to the CS(+), whereas responses to the CS(-) decreased. Such changes have never been observed in the amygdala except in cases where the CS(-) had been paired to the US before and fear responses not extinguished. This suggests that fear conditioning is not only accompanied by potentiation of amygdalopetal pathways conveying the CS(+) but also by the depression of sensory inputs unpaired to noxious stimuli.     

Age-dependent consequences of seizures: relationship to seizure frequency, brain damage, and circuitry reorganization

Seizures in the developing brain pose a challenge to the clinician. In addition to the acute effects of the seizure, there are questions regarding the impact of severe or recurrent seizures on the developing brain. Whether provoked seizures cause brain damage, synaptic reorganization, or epilepsy is of paramount importance to patients and physicians. Such questions are especially relevant in the decision to treat or not treat febrile seizures, a common occurrence in childhood. These clinical questions have been addressed using clinical and animal research. The largest prospective studies do not find a causal connection between febrile seizures and later temporal lobe epilepsy. The immature brain seems relatively resistant to the seizure-induced neuronal loss and new synapse formation seen in the mature brain. Laboratory investigations using a developmental rat model corresponding to human febrile seizures find that even though structural changes do not result from hyperthermic seizures, synaptic function may be chronically altered. The increased understanding of the cellular and synaptic mechanisms of seizure-induced damage may benefit patients and clinicians in the form of improved therapies to attenuate damage and changes induced by seizures and to prevent the development of epilepsy.     

Dissociation, psychopathology, and abusive experiences in a nonclinical Latino university student group

A variety of clinical and experimental data suggest that many individuals who report abusive and traumatic experiences also report a wide array of dissociative and other psychopathological symptoms. In this study, 198 Puerto Rican undergraduate students participated in a study to examine the possible relationship between different types of traumatic experiences and the self-report of dissociative experiences, depressive symptoms, and general psychopathology. Another aspect of this study was the examination of the psychometric properties of the Dissociative Experiences Scale (DES) in a Latino sample. Results supported the hypothesis that those individuals who reported frequent and severe traumatic experiences were also the most likely to experience psychological malaise and scored higher on the DES. Of interest was the finding that the psychometric characteristics of the DES are consistent with those reported in the United States and other countries. The authors conclude that individuals with a marked history of trauma and abuse are more likely to use dissociative defenses as a coping response.     

Duration estimation and the phonological loop: Articulatory suppression and irrelevant sounds

Clock-based theories of time estimation propose that clock pulses are accumulated in working memory. Although these theories do not constrain the form of the memory trace, evidence reported in the literature suggests that active manipulation of a verbal trace may be involved. Four experiments are reported in which participants reproduced or verbally estimated short durations (up to a few seconds) either in a single-task condition or in a condition with a phonological load. Experiments 1, 2 and 4 showed that both interval reproduction and verbal estimation were impaired under concurrent articulatory suppression in comparison to a timing only control condition. Neither irrelevant speech (Experiments 1-3) nor irrelevant tones and music (Experiment 3) impaired timing performance. These findings are taken to show that time estimation is mediated by phonological working memory and the involvement of an active articulatory rehearsal process.     

Qualitative differences between implicit and explicit sequence learning

Four experiments investigate the differences between implicit and explicit sequence learning concerning their resilience to structural and superficial task changes. A superficial change that embedded the SRT task in the context of a selection task, while maintaining the sequence, did selectively hinder the expression of implicit learning. In contrast, a manipulation that maintained the task surface, but decreased the sequence validity, affected the expression of learning specifically when it was explicit. These results are discussed in the context of a dynamic framework (Cleeremans & Jiménez, 2002), which assumes that implicit knowledge is specially affected by contextual factors and that, as knowledge becomes explicit, it allows for the development of relevant metaknowledge that modulates the expression of explicit knowledge.     

Executive function deficits in autism spectrum disorders and attention-deficit/hyperactivity disorder: examining profiles across domains and ages

Deficits in 'executive function' (EF) are characteristic of several clinical disorders, most notably Autism Spectrum Disorders (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD). In this study, age- and IQ-matched groups with ASD, ADHD, or typical development (TD) were compared on a battery of EF tasks tapping three core domains: response selection/inhibition, flexibility, and planning/working memory. Relations between EF, age and everyday difficulties (rated by parents and teachers) were also examined. Both clinical groups showed significant EF impairments compared with TD peers. The ADHD group showed greater inhibitory problems on a Go-no-Go task, while the ASD group was significantly worse on response selection/monitoring in a cognitive estimates task. Age-related improvements were clearer in ASD and TD than in ADHD. At older (but not younger) ages, the ASD group outperformed the ADHD group, performing as well as the TD group on many EF measures. EF scores were related to specific aspects of communicative and social adaptation, and negatively correlated with hyperactivity in ASD and TD. Within the present groups, the overall findings suggested less severe and persistent EF deficits in ASD (including Asperger Syndrome) than in ADHD.     

Self-concept in adults from Spain and Portugal

The aim of this work is to confirm the penta-factorial validity of the AF5 Self-Concept Questionnaire in Spanish and Portuguese adults. From the responses of a total of 2058 adults (1508 Spanish, 73.3%, and 550 Portuguese, 26.7%) was analyzed the reliability of the instrument, was compared the validity of the 5 oblique factor model proposed by the authors versus unifactorial and the orthogonal alternative models, and was studied the invariance of the Portuguese translation. The results of structural equation modeling supported the authors' penta-factorial model. The multi-group factorial invariance showed that Portuguese translation of the AF5 does not change neither the original factor weights, nor the variances and covariances of the factors. Finally, the reliability was good for the original Spanish version and Portuguese translation.