Operant performance of rats reared for short and long periods on nutritionally adequate diets varied in fat, carbohydrate, and protein content.
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The purpose of this experiment was to compare the executive functioning performance of children with autism with chronological- and verbal-matched controls in a spatial-reversal task. Three groups of children participated in this experiment. One group was identified as having autism (7 boys), the 2nd group contained 7 typically developing children (6 boys, 1 girl) who were matched to the 1st group based on their verbal performance, and the 3rd group contained 7 typically functioning children (6 boys, 1 girl) matched to the 1st group based on chronological age. Each group was given a spatial-reversal task containing 2 problems. In the 1st problem, children selected a toy on a particular side in a pair. In the 2nd problem, the contingencies were reversed such that children were to choose the toy on the opposite side. Children with autism generally performed worse than comparison groups as indicated by their overall higher rate of errors. However, these results must be qualified by considering the performance for each problem: Errors for the children with autism were infrequent during the 1st problem but increased in the 2nd, whereas errors for comparison children showed the opposite pattern. When these results from the spatial-reversal task were interpreted from the perspective of hypothesis-testing theory, the executive functioning deficiency of children with autism was found to involve the selection and testing of stereotypic response sets that were not likely to be revised or changed flexibly according to feedback from the environment or the demands of the task.
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This study had two goals. One was to assess whether the WMS-III Spatial Span subtest operates as a visual analogue of Digit Span while the second was to determine whether backward span is a more sensitive measure of working memory than the forward span condition. Analyses based on the WAIS-III-WMS-III standardization and clinical group data revealed some important distinctions between Digit and Spatial Span. The two tasks exhibited differences in patterns of performance on the forward versus backward conditions, in their relationships with age, and in their methodology. Moreover, the backward conditions of both Digit and Spatial Span did not appear more affected by risk factors such as aging or pathology than the forward scores. This runs contrary to the widespread notion that backward span provides differential sensitivity regarding working memory processing.
Behavioral Dyscontrol Scale (BDS) is a clinical measure previously shown to be related to frontal lobe integrity, executive abilities, and functional independence. Electronic version of the scale (BDS-EV) was developed and its reliability and validity were examined. The BDS-EV, the original BDS, and a brief battery of traditional clinical tests were administered to 55 community-dwelling adults ages 18 to 68. The results yielded high internal consistency and provided support for convergent, discriminant, and incremental validity. Overall, the results demonstrate the feasibility of converting the BDS into an electronic instrument and support continued research and development of this instrument.
Attention-deficit hyperactivity disorder (ADHD) has been considered a mental illness in which the frontal lobe is dysfunctional. The orbitofrontal cortex (OFC) controls emotional and motivational behaviors which are impaired in ADHD. Patients with OFC damage have shown impaired performance in reversal and extinction tasks in a simple go/no-go paradigm. We assigned ADHD subjects the two tasks to examine a hypothesized dysfunction of OFC. ADHD subjects indeed showed a performance deficit in the tasks, supporting OFC dysfunction in ADHD. Furthermore, a discriminat analysis using the task performance variables correctly classified 89.7% of the participants among ADHD patients and normal controls.
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Previous findings indicate that the basolateral amygdala (BLA) and the nucleus accumbens (NAc) interact in influencing memory consolidation. The current study investigated whether this interaction requires concurrent dopamine (DA) receptor activation in both brain regions. Unilateral, right-side cannulae were implanted into the BLA and the ipsilateral NAc shell or core in male Sprague-Dawley rats ( approximately 300 g). One week later, the rats were trained on an inhibitory avoidance (IA) task and, 48 h later, they were tested for retention. Drugs were infused into the BLA and NAc shell or core immediately after training. Post-training intra-BLA infusions of DA enhanced retention, as assessed by latencies to enter the shock compartment on the retention test. Infusions of the general DA receptor antagonist cis-Flupenthixol (Flu) into the NAc shell (but not the core) blocked the memory enhancement induced by the BLA infusions of DA. In the reverse experiment, post-training intra-NAc shell infusions of DA enhanced retention and Flu infusions into the BLA blocked the enhancement. These findings indicate that BLA modulation of memory consolidation requires concurrent DA receptor activation in the NAc shell but not the core. Similarly, NAc shell modulation of memory consolidation requires concurrent DA receptor activation in the BLA. Together with previous findings, these results suggest that the dopaminergic innervation of the BLA and NAc shell is critically involved in the modulation of memory consolidation.
The present study was designed to investigate verbal and spatial short-term memory abilities in persons with Down's syndrome (DS) and intellectual disability (ID) of different aetiology. For this purpose, we compared performances of DS (n = 15; mean mental age = 5.2 years; SD = 1.2 years; mean chronological age = 16.6 years; SD = 2.9 years) and ID subjects (n = 14; mean mental age = 5.8 years; SD = 2.1 years; mean chronological age = 16.4 years; SD = 2.5 years) with those of normally developed subjects matched for mental age (n = 24) on tasks of forward and backward immediate recall of verbal and spatial sequences. Our results are discussed in the light of the Working Memory model developed by Baddeley (1986, 1990). Altogether, our data documents a deficit of verbal and spatial backward spans in persons with DS. The deficit seems to be specific for this particular aetiology group, confirming the hypothesis that ID is not a uniform condition, characterized by an undifferentiated delay of the cognitive development, but rather that it is characterized by a deficit in a complex cognitive system in which some cognitive abilities can be disrupted more than others (Detterman 1987; Vicari et al. 1992).
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Necker cube reversals were studied in a group of 24 arrested men in three experimental sessions; two weeks, one week and immediately before trial. The first session was assumed to represent a moderate laboratory stress due to the novelty of the situation, and the last session a real-life stress associated with anticipation of appearing in court. Both were superimposed on the sustained real-life stress of being in jail. There were no stress-related changes between the three sessions in the rate of apparent change (RAC) of the Necker cube. The intra-individual stability of RAC was extremely high. There were significant positive correlations between RAC in all sessions, and a psychopathy-related inventory scale, the Gough delinquency scale.
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