The Dynamics and Neural Correlates of Audio-Visual Integration Capacity as Determined by Temporal Unpredictability, Proactive Interference, and SOA.

Over 5 experiments, we challenge the idea that the capacity of audio-visual integration need be fixed at 1 item. We observe that the conditions under which audio-visual integration is most likely to exceed 1 occur when stimulus change operates at a slow rather than fast rate of presentation and when the task is of intermediate difficulty such as when low levels of proactive interference (3 rather than 8 interfering visual presentations) are combined with the temporal unpredictability of the critical frame (Experiment 2), or, high levels of proactive interference are combined with the temporal predictability of the critical frame (Experiment 4). Neural data suggest that capacity might also be determined by the quality of perceptual information entering working memory. Experiment 5 supported the proposition that audio-visual integration was at play during the previous experiments. The data are consistent with the dynamic nature usually associated with cross-modal binding, and while audio-visual integration capacity likely cannot exceed uni-modal capacity estimates, performance may be better than being able to associate only one visual stimulus with one auditory stimulus.

Item-nonspecific proactive interference in monkeys' auditory short-term memory.

Recent studies using the delayed matching-to-sample (DMS) paradigm indicate that monkeys' auditory short-term memory (STM) is susceptible to proactive interference (PI). During the task, subjects must indicate whether sample and test sounds separated by a retention interval are identical (match) or not (nonmatch). If a nonmatching test stimulus also occurred on a previous trial, monkeys are more likely to incorrectly make a "match" response (item-specific PI). However, it is not known whether PI may be caused by sounds presented on prior trials that are similar, but nonidentical to the current test stimulus (item-nonspecific PI). This possibility was investigated in two experiments. In Experiment 1, memoranda for each trial comprised tones with a wide range of frequencies, thus minimizing item-specific PI and producing a range of frequency differences among nonidentical tones. In Experiment 2, memoranda were drawn from a set of eight artificial sounds that differed from each other by one, two, or three acoustic dimensions (frequency, spectral bandwidth, and temporal dynamics). Results from both experiments indicate that subjects committed more errors when previously-presented sounds were acoustically similar (though not identical) to the test stimulus of the current trial. Significant effects were produced only by stimuli from the immediately previous trial, suggesting that item-nonspecific PI is less perseverant than item-specific PI, which can extend across noncontiguous trials. Our results contribute to existing human and animal STM literature reporting item-nonspecific PI caused by perceptual similarity among memoranda. Together, these observations underscore the significance of both temporal and discriminability factors in monkeys' STM.

Incremental validity of proactive personality over the big five for predicting job performance of software engineers in an innovative context / Validez añadida de la personalidad proactiva sobre los «Cinco Grandes» para predecir el desempeño en el puesto de ingenieros de software en un contexto innovador

This study examined the incremental validity of proactive personality for predicting overall job performance over the Big Five in the context of an innovative software engineering job. Proactive personality and the Big Five were measured in a sample of 243 engineers and overall job performance was assessed through supervisor ratings in a sub-sample of 95 of these engineers. Results showed that even though proactive personality represents a valid and important predictor of performance it does not show a relevant increment on the prediction yielded by extraversion, openness, conscientiousness, emotional stability and organizational tenure. Implications for the relevancy and practical value of proactive personality for personnel selection are discussed(AU)

Este estudio examina la validez añadida de la personalidad proactiva sobre los «cinco grandes» para predecir el desempeño en el trabajo en el contexto de un puesto de trabajo de ingeniero de software. La personalidad proactiva y los «cinco grandes» fueron medidos en una muestra de 243 ingenieros y el desempeño global fue evaluado mediante valoraciones del supervisor en una sub-muestra de 95 de estos ingenieros. Los resultados mostraron que aun cuando la personalidad proactiva representa un importante y válido predictor del desempeño no muestra un incremento relevante en la predicción producida por la extraversión, apertura, conciencia, estabilidad emocional y antigüedad en el puesto. Se discuten las implicaciones, la relevancia y el valor práctico de la personalidad proactiva para la selección de personal(AU)

Age differences in poignancy: Cognitive reappraisal as a moderator.

Poignancy is defined as a mixed emotional experience that arises when one faces meaningful endings. According to socioemotional selectivity theory (Carstensen, 2006), when people are aware of the finitude of time, they tend to experience more poignancy. In Study 1, we found that Chinese younger, but not older, participants experienced more poignancy under time limitations. In Study 2, we found that an emotion regulation strategy-namely, cognitive reappraisal-moderated the relationship between limited time and poignancy, such that the increases in poignancy under time limitations were found only among older Chinese participants with lower levels of cognitive reappraisal but not among those with higher levels of cognitive reappraisal. These findings contribute to the existing literature on poignancy by showing that not every older adult exhibits poignancy in the face of an ending: The poignancy phenomenon may occur among only older adults who are less likely to use an emotion regulation strategy, such as cognitive reappraisal, to reinterpret the anticipated ending. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Role of the substantia nigra pars reticulata in sensorimotor gating, measured by prepulse inhibition of startle in rats.

The substantia nigra pars reticulata (SNR) is one of the major output nuclei of the basal ganglia. It connects the dorsal and ventral striatum with the thalamus, superior colliculus and pontomedullary brainstem. The SNR is therefore in a strategic position to regulate sensorimotor behavior. We here assessed the effects of SNR lesions on prepulse inhibition (PPI) of the acoustic startle response (ASR), stereotypy and locomotion in drug-free rats, as well as after systemic administration of the dopamine agonist DL-amphetamine (2 mg/kg), and the NMDA receptor antagonists dizocilpine (0.16 mg/kg) and CGP 40116 (2 mg/kg). SNR lesions reduced PPI, enhanced spontaneous sniffing and potentiated the locomotor stimulation by dizocilpine and CGP 40116. PPI was impaired by dizocilpine and CGP 40116 in controls. The ASR was enhanced in controls by dizocilpine and amphetamine. SNR lesions prevented the enhancement of the ASR by amphetamine. A second experiment tested the hypothesis that the SNR mediates PPI via a GABAergic inhibition of the startle pathway. Infusion of the GABA(B) antagonist phaclofen but not the GABA(A) antagonist picrotoxin into the caudal pontine reticular nucleus reduced PPI. Hence, lesion of the SNR reduces sensorimotor gating possibly by elimination of a nigroreticular GABAergic projection interacting with GABA(B) receptors. Moreover, destruction of the SNR enhances the motor stimulatory effects of amphetamine and of the NMDA antagonists dizocilpine and CGP 40116. We conclude that the SNR exerts a tonic GABAergic inhibition on sensorimotor behavior that is regulated by the dorsal and the ventral striatum.

Impaired prepulse inhibition of acoustic startle in schizophrenia.

BACKGROUND: Schizophrenics show deficits in sensorimotor gating, as measured by prepulse inhibition of acoustic startle (PPI). The goal of this investigation is to further characterize PPI and habituation deficits in schizophrenia, and to examine whether differing subgroups of schizophrenics would show comparable PPI deficits. METHODS: PPI was measured in 24 male schizophrenic subjects (9 acutely decompensated inpatients and 15 stable outpatients) and in 20 age-matched normal control subjects. Schizophrenic subjects were rated for positive and negative symptoms at the time of testing. RESULTS: Schizophrenic subjects showed deficits in prepulse inhibition and habituation as compared to normal subjects. Similar latency facilitation was produced by the prepulse in both groups. Acutely decompensated inpatients and stable outpatients did not differ in percent PPI. PPI did not correlate with severity of positive or negative symptoms. CONCLUSIONS: These results suggest that schizophrenic subjects have impaired central inhibitory mechanisms as measured by PPI, and support the hypothesis that periods of relative clinical remission are not accompanied by normalization of sensorimotor gating.

Antipsychoticlike effects of amoxapine, without catalepsy, using the prepulse inhibition of the acoustic startle reflex test in rats.

BACKGROUND: The dibenzoxazepine amoxapine was introduced as an antidepressant but has shown antipsychoticlike activity in a number of animal screening tests. A recent positron emission tomography study showed a 5-HT(2)/D(2) receptor occupancy profile of amoxapine that is very similar to that of established atypical antipsychotics. Schizophrenics display deficits in sensory gating mechanisms, such as prepulse inhibition (PPI) of the acoustic startle reflex. A similar deficit can be produced by dopamine (DA) and by 5-HT(2A/C) receptor agonists in rats. Antipsychotic compounds reverse this effect. METHODS: Effects of amoxapine on apomorphine- or 1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI)-induced disruption of PPI were studied in adult male Sprague-Dawley rats. The extrapyramidal side effect (EPS) liability of amoxapine was assessed using the inclined grid catalepsy (CAT) test. Statistical analyses were performed by analysis of variance (ANOVA) for fully repeated measures (PPI) and by the Kruskal-Wallis one-way ANOVA by ranks (CAT). RESULTS: Apomorphine (0.5 mg/kg) produced a significant reduction in PPI compared with the case of rats in the saline control group. Pretreatment with amoxapine (10 mg/kg) significantly attenuated the apomorphine-induced disruption of PPI. DOI (0.5 mg/kg) significantly reduced PPI compared with saline controls. Pretreatment with amoxapine (5 or 10 mg/kg) produced a significant attenuation of the DOI-induced disruption of PPI. Amoxapine by itself did not alter PPI. Amoxapine (5 or 10 mg/kg) did not produce CAT. CONCLUSIONS: The DA D(2)/5-HT(2) receptor antagonist amoxapine produced an antipsychoticlike reversal of both apomorphine- and DOI-induced disruption of PPI. Furthermore, the same doses of amoxapine that reversed disruption of PPI did not produce CAT. The results confirm and lend further support to the results of previous studies on amoxapine, suggesting that amoxapine might possess antipsychotic activity with little propensity for producing EPS.

Further analysis of encoding in patients with Huntington's disease.

Arguments favoring the view that derangement of normal encoding processes contributes to the memory defects of patients with Huntington's disease (HD) are supported by the finding that HD patients do not learn highly imageable words more rapidly than they learn words that are difficult to image. But other data indicating that HD patients can use verbal mediators as mnemonic aids for picture recognition question the existence of important and general encoding deficits in HD. In the first of two experiments the influence of imagery on the acquisition and recall of 14-word lists was studied using a free-recall paradigm. Both HD patients and controls learned highly imageable words more quickly and retained them better than low imagery words over a 30-min delay. The impact of imagery on learning was apparent by the first trial. In the second experiment, a modified Brown-Peterson distractor paradigm was used to assess release from proactive interference (PI). It was found that both HD patients and controls exhibited comparable release from PI following a shift in taxonomic categories. The results of both experiments question the importance of encoding deficits in the memorial dysfunctions associated with HD.

Amnesia in a patient with bilateral lesions to the thalamus.

A case of anterograde amnesia is described in a 38-yr-old man with bilateral thalamic lesions. The patient appeared to have suffered no general intellectual loss and performed normally on standard memory tasks involving immediate recall of new material. There was, however, consistent impairment in recalling material, verbal and non-verbal, over delays as brief as a few seconds. Impairment was especially marked on tests involving free recall and partial cueing procedures; recognition memory was also impaired. Premorbid memory tested normally and susceptibility to interference was less than in other organic amnesics. Various interpretations of the patient's amnesia were considered but a deficit at the initial stages of information processing appeared to be indicated.