Aging: a switch from automatic to controlled processing of sounds?

In this article, the authors show that aging differentially affects peoples' ability to automatically and voluntarily process auditory information. Young, middle-aged, and older adults matched behaviorally in an auditory discrimination task showed similar patterns of neural activity indexing the voluntary and conscious detection of deviant (i.e., target) stimuli. In contrast, a negative wave indexing automatic processing (the mismatch negativity) was elicited only in young adults for near-threshold stimuli. These results indicate that aging affects the ability to automatically register small changes in a stream of homogeneous stimuli. However, this age-related decline in automatic detection of small change in the auditor environment can be compensated for by top-down controlled processes.     

Neurophysiological evidence for disturbances of conflict processing in patients with schizophrenia

Deficits in cognition are a hallmark of schizophrenia. In the present study, the authors investigated the effects of schizophrenia on the neural correlates of conflict processing in a single-trial version of the Stroop task by using event-related brain potentials. Relative to matched controls, patients with schizophrenia showed increased Stroop interference in response time, but this effect was eliminated when the effect of response slowing was controlled. In controls, conflict processing was associated with a negative wave peaking between 400 and 500 ms (N450) and conflict sustained potential (SP) peaking between 600 and 800 ms after stimulus onset. In patients with schizophrenia, the amplitude of the N450 was significantly attenuated and the conflict SP was absent. These results provide evidence for the existence of altered neural processes associated with conflict processing that may be associated with dysfunction of the anterior cingulate and prefrontal cortex in patients with schizophrenia.     

Hemispheric lateralization of the EEG during wakefulness and REM sleep in young healthy adults

EEG recordings confirm hemispheric lateralization of brain activity during cognitive tasks. The aim of the present study was to investigate spontaneous EEG lateralization under two conditions, waking and REM sleep. Bilateral monopolar EEG was recorded in eight participants using a 12-electrode montage, before the night (5 min eyes closed) and during REM sleep. Spectral analysis (0.75-19.75 Hz) revealed left prefrontal lateralization on total spectrum amplitude power and right occipital lateralization in Delta activity during waking. In contrast, during REM sleep, right frontal lateralization in Theta and Beta activities and right lateralization in occipital Delta activity was observed. These results suggest that spontaneous EEG activities generated during waking and REM sleep are supported in part by a common thalamo-cortical neural network (right occipital Delta dominance) while additional, possibly neuro-cognitive factors modulate waking left prefrontal dominance and REM sleep right frontal dominance.     

Decision making and interference in the domestic cat (Felis catus)

Domestic cats (Felis catus) received a task in which an obstacle was introduced at the time they were ready to reach for 1 among 2 or 3 baited targets. The results revealed that when the initially chosen direction (i.e., before the introduction of the obstacle) and the new one were orthogonal, the cats reassessed distance, angular deviation, and visibility once they had turned around the obstacle (Experiments 1, 2, and 3). Then the cats chose a different target than the one that would have been chosen had there been no obstacle. When both the initially chosen and the new direction matched (Experiment 4), the cats kept intact their initial decision. The discussion focuses on the nature of the representational system of the cat. The discussion also emphasizes comparisons with dogs (i.e., cooperative hunters).     

Levels of consciousness and self-awareness: A comparison and integration of various neurocognitive views

Quite a few recent models are rapidly introducing new concepts describing different levels of consciousness. This situation is getting confusing because some theorists formulate their models without making reference to existing views, redundantly adding complexity to an already difficult problem. In this paper, I present and compare nine neurocognitive models to highlight points of convergence and divergence. Two aspects of consciousness seem especially important: perception of self in time and complexity of self-representations. To this I add frequency of self-focus, amount of self-related information, and accuracy of self-knowledge. Overall, I conclude that many novel concepts (e.g., reflective, primary, core, extended, recursive, and minimal consciousness) are useful in helping us distinguish between delicate variations in consciousness and in clarifying theoretical issues that have been intensely debated in the scientific literature--e.g., consciousness in relation to mirror self-recognition and language.     

Word frequency and the mixed-list paradox in immediate and delayed serial recall

In free recall tasks, when low- and high-frequency items are mixed within the to-be-remembered lists, the usual recall advantage found for high-frequency words is eliminated or reversed. Recently, this mixedlist paradox has also been demonstrated for short-term serial recall (Hulme, Stuart, Brown, & Morin, 2003). Although a number of theoretical interpretations of this mixed-list paradox have been proposed, researchers have also suggested that it could simply be a result of participant-controlled strategies (M. J. Watkins, LeCompte, & Kim, 2000). The present study was designed to assess whether this explanation could be applied to immediate and delayed serial recall. The results showed that high-frequency words were recalled better than low-frequency words in pure lists, but that this effect was eliminated in mixed lists, whether they were given under intentional or incidental learning conditions. This pattern suggests that the mixed-list paradox cannot be explained by participant-controlled strategies.     

Sequential combinations of drug and cognitive behavioral therapy for chronic insomnia: an exploratory study

This study explores the efficacy of sequential treatments involving medication and cognitive behavioral treatment (CBT) for primary insomnia. Seventeen participants took part in a multiple baseline design and were assigned to: (a) medication for 5 weeks, followed by combined medication plus CBT for 5 weeks; (b) combined treatment for 5 weeks, followed by CBT alone; or (c) CBT alone. Each treatment sequence produced significant sleep improvements, but at different points in time. For the first sequence, most of the sleep improvement was obtained after the introduction of CBT, while for the other sequence and CBT alone, improvement appeared during the first weeks. These results suggest that sleep improvement seems affected by the way treatments are combined. Also, a sequence beginning with a combined treatment followed by CBT alone seems to produce the best outcome. Additional research should be conducted with larger samples to determine the most effective sequence.     

Body-esteem, body mass index, and risk for disordered eating among adolescents in synchronized swimming

The aim of this study was to examine dimensions of body-esteem, Body Mass Index, and their relations with eating disorder symptoms among 42 elite adolescent athletes engaged in competitive synchronized swimming (M = 15.4 yr., SD = 1.2) and to compare them with 40 athletes in sports with no emphasis on leanness (M = 16.5 yr., SD = .93), and 50 nonathlete college female students (M = 16.3 yr., SD = 1.1). They completed the Body-esteem Scale and the Eating Attitudes Test, and the Body Mass Index was computed. Analysis showed synchronized swimmers reported greater negative feelings about their appearance than the two other groups and low perceptions of how others evaluate their physical appearance. Participants did not differ on the EAT-26. Regression analyses showed that Body Mass Index and Body-esteem Appearance accounted for 38% of the variance in log-transformed Dieting scores of synchronized swimmers. Results are discussed in relation to the literature.