Oscillatory brain dynamics, wavelet analysis, and cognition

On the basis of a systems theoretical approach it was hypothesized that event-related potentials (ERPs) are superpositions of stimulus-evoked and time-locked EEG rhythms reflecting resonance properties of the brain (Ba?ar, 1980). This approach led to frequency analysis of ERPs as a way of analyzing evoked rhythms. The present article outlines the basic features of ERP frequency analysis in comparison to ERP wavelet analysis, a recently introduced method of time-frequency analysis. Both methods were used in an investigation of the functional correlates of evoked rhythms where auditory and visual ERPs were recorded from the cat brain. Intracranial electrodes were located in the primary auditory cortex and in the primary visual cortex thus permitting "cross-modality" experiments. Responses to adequate stimulation (e.g., visual ERP recorded from the visual cortex) were characterized by high amplitude alpha (8-16 Hz) responses which were not observed for inadequate stimulation. This result is interpreted as a hint at a special role of alpha responses in primary sensory processing. The results of frequency analysis and of wavelet analysis were quite similar, with possible advantages of wavelet methods for single-trial analysis. The results of frequency analysis as performed earlier were thus confirmed by wavelet analysis. This supports the view that ERP frequency components correspond to evoked rhythms with a distinct biological significance.     

Health and educational outcomes of children who experienced severe neonatal medical complications.

To determine the long-term developmental and educational outcomes of a sample of low birthweight infants with intraventricular hemorrhage (IVH), the authors conducted developmental assessments and interviews 8 years after the initiation of an early intervention project. At the time of the follow-up, 62% of the children were experiencing some developmental or behavior problems, with visual impairments, cerebral palsy, and attention deficits occurring most frequently. Grade of IVH and the number of days spent in the neonatal intensive care unit were the best predictors of later developmental delays. The sample also scored below average on school achievement; approximately 30% of those in school were eligible for special education services. These findings corroborate results from investigations with similar populations whose birth characteristics put them at risk for subsequent developmental delay.     

Two Approaches for Identifying Shared Personality Dimensions Across Methods

Two approaches are illustrated, one exploratory and one confirmatory, or determining the extent to which personality dimensions are invariant across different methods of measurement. Using the interbattery factor model (Browne, 1979, 1980; Tucker, 1958), Study 1 explores the links between the Five-Factor Model of Personality, as assessed by the NEO-PI (Costa & McCrae, 1985), and the Needs system of Murray, as assessed by the Personality Research Form (Jackson, 1984). Study 2 uses an interbattery approach to examine the common structure underlying two widely used coping measures: the revised Ways of Coping Cchecklis (Folkman, Lazarus, Dunkel-Schetter, Delongis, & Gruen, 1986) and the COPE Inventory (Carver, Scheier, & Weintraub, 1989). The two studies illustrate the use of interbattery factor analysis as a means of separating battery-specific (method) factors from interbattery (trait) factors, in contrast to traditional factor analysis that describes underlying structure without regard to method of measurement. By maintaining the distinction between variability that is method-specific and variability that is common across methods, the interbattery factor model allows the common trait structure underlying multiple measures to be described more accurately.     

Impairments of attention following childhood traumatic brain injury.

Attentional deficits are commonly reported following traumatic brain injury (TBI) in adults, although the occurrence of such problems is less well documented in young children. This study aimed to investigate residual attentional abilities associated with TBI during childhood, by examining a number of aspects of attention including sustained, focussed, and divided attention, attentional shift, and response inhibition. Eighteen children with a history of TBI, aged between 8 and 14 years and 18 non-injured matched controls participated in the study. Results show that attentional skills may be differentially impaired after TBI, with children who have sustained moderate-to-severe TBI exhibiting significant deficits on the following attentional domains: sustain, focus, and response inhibition. These findings support the view that attentional impairments following pediatric TBI, while not global, may be more generalized than those reported for adult samples, perhaps reflecting the relative immaturity of attentional skills at the time of injury.     

Interaction of the Dopaminergic System With Mechanisms of Associative Learning and Cognition:Implications for Drug Abuse

The possible role of mechanisms of associative learning in drug abuse and addiction is considered with respect to psychomotor stimulant drugs such as cocaine and amphetamine. Although the initial sites of the reinforcing effects of these drugs are associated with the mesolimbic dopamine projection to the nucleus accumbens, other important neuromodulatory influences are identified. These include the amygdala, which appears to mediate the associative processes by which environmental stimuli come to control drug-seeking behavior. Possible parallel mechanisms by which stimulant drugs enhance effects of aversive as well as rewarding stimuli are discussed. The importance of attribution and context in determining relative rewarding and aversive effects is pointed out. These attributional and contextual factors may be a function of cortical regions that may themselves be impaired by chronic drug abuse, leading to further dysexecutive control over cognition and behavior.     

Construct validity of the Sivik Psychosomaticism Test and test of operational style: correlations with Karolinska Scheme of Personality.

To evaluate the construct validity (convergent and divergent) of Sivik Psycho Somaticism test (SPS) and test of Operationality (OPER), Pearson correlation coefficients between SPS scales and subscales and Karolinska Scheme of Personality (KSP) were calculated. Seventy-eight healthy individuals and 196 psychosomatic patients completed the SPS and OPER tests and KSP. The results show that the SPS and OPER subscales are significantly correlated to most KSP subscales. The correlations were higher for the psychosomatic group than for the normal population. The results confirm the validity of the SPS and OPER constructs.     

Timeless demonstrations of Parkinson's first law

"Work expands so as to fill the time available for its completion," Parkinson's law, is an explanation classic that has survived without an artifact-free demonstration at the individual level. To evaluate Parkinson's law, undergraduate subjects expected to judge four sets of photos of faces with reference to a subjective criterion. The experimental subjects, who were told that the fourth set was canceled before they began work on the third set, dallied on the third set; that is, as compared with controls, they prolonged work. The cancellation-dalliance effect was reobtained in two exact replications. It was obtained again in a fourth study, a conceptual replication wherein subjects processed negatively toned phrases against an objective criterion. The generalizability of the effect and explanations for it are discussed.