Resting EEG and behavioural correlates of interhemispheric transfer times.

Correlations between the relative speeds of left-to-right and right-to-left interhemispheric transfer times and resting quantitative electroencephalography activity were examined in order to determine if variability in interhemispheric transfer was related to individual variability in resting neural firing patterns. Resting electroencephalograph frequencies for 32 participants were regressed for 4 frequency bands at 8 different locations calculated for asymmetrical activation through subtracting the left from right average spectral power of each. Participants also completed a series of behavioural tasks that are typically localized to the right hemisphere (RH). Results indicate that the frontal medial average spectral power of the beta band is correlated with the speed of transfer such that larger resting beta values in the right as compared to left location are associated with faster right-to-left interhemispheric transfer times and that larger resting beta values in the left as compared to right location are associated with faster left-to-right interhemispheric transfer times. Furthermore, enhanced performance on tasks typically localized to the RH is correlated with slower right-to-left interhemispheric transfer times, suggesting that the dominance of one hemisphere may come at a cost to interhemispheric communication.

Neurosciences and adult health behaviors: recent findings and implications for counseling psychology.

The current review comprehensively examines recent advances in 2 innovative areas of neuroscience research on healthy adults regarding neuropsychosocial interactions on human cognition and behavior, as well as implications for counseling psychologists conducting research and in practice. Advances in how oxytocin influences prosocial behavior and the mitigation of social stress, and the influence of environmentally mediated gene expressions on the development of attachment disorders are surveyed and discussed in terms of how counseling psychologists might best integrate recent neuroscience research into a framework for therapeutic intervention.

The relationship between neural processing efficiency during inter-hemispheric transfer, alcohol consumption, and sleep quality in college students: an ERP study.

Objective: To examine relationships between sleep, alcohol consumption, and a physiological and behavioral marker of cognitive function in college students. College students are in a high risk category for high alcohol consumption and poor sleep quality, two unhealthful behaviors which can lead to poor mental health outcomes and compromised academic performance. Participants: Thirty college students from a large midwestern institution. Methods: Participants performed an interhemispheric transfer task while their electroencephalography was recorded for later examination of event-related potentials. They were also administered the Pittsburgh Sleep Quality Index, the Alcohol Use Disorders Identification Test, and the Alcohol Timeline Follow-Back. Results: Results demonstrate that increased alcohol consumption is associated with poor right-to-left interhemispheric transfer performance, and increased frontal P1 ERP amplitudes to neuro-ipsilateral targets requiring an interhemispheric-transfer. Conclusions: These findings assist in furthering explorations into the impacts of unhealthy behaviors in college students and underlying markers of simple cognitive and behavioral function.

Underlying neural alpha frequency patterns associated with intra-hemispheric inhibition during an interhemispheric transfer task.

Interhemispheric transfer measured via differences in right- or left-handed motoric responses to lateralized visual stimuli, known as the crossed-uncrossed difference (CUD), is one way of identifying patterns of processing that are vital for understanding the transfer of neural signals. Examination of interhemispheric transfer by means of the CUD is not entirely explained by simple measures of response time. Multiple processes contribute to wide variability observed in CUD reaction times. Prior research has suggested that intra-hemispheric inhibitory processes may be involved in regulation of speed of transfer. Our study examined electroencephalography recordings and time-locked alpha frequency activity while 18 participants responded to lateralized targets during performance of the Poffenberger Paradigm. Our results suggest that there are alpha frequency differences at fronto-central lateral electrodes based on target, hand-of-response, and receiving hemisphere. These findings suggest that early motoric inhibitory mechanisms may help explain the wide range of variability typically seen with the CUD.

Alpha band frequency differences between low-trait and high-trait anxious individuals.

Trait anxiety has been shown to cause significant impairments on attentional tasks. Current research has identified alpha band frequency differences between low-trait and high-trait anxious individuals. Here, we further investigated the underlying alpha band frequency differences between low-trait and high-trait anxious individuals during their resting state and the completion of an inhibition executive functioning task. Using human participants and quantitative electroencephalographic recordings, we measured alpha band frequency in individuals both high and low in trait anxiety during their resting state, and while they completed an Eriksen Flanker Task. Results indicated that high-trait anxious individuals exhibit a desynchronization in alpha band frequency from a resting state to when they complete the Eriksen Flanker Task. This suggests that high-trait anxious individuals maintain fewer attentional resources at rest and must martial resources for task performance as compared with low-trait anxious individuals, who appear to maintain stable cognitive resources between rest and task performance. These findings add to the cognitive neuroscience literature surrounding the role of alpha band frequency in low-trait and high-trait anxious individuals.

Study Habits, Motives, and Strategies of College Students With Symptoms of ADHD.

OBJECTIVE: Studies on ADHD in educational settings indicate that a student's motivation for learning is significantly related with the student's grade point average. The present study examined the relationship between ADHD symptoms and student academic achievement by considering the student's approach to and motivation for learning. METHOD: Participants completed a questionnaire that breaks down learning strategies into a surface or deep approach. Each approach is then divided into a deep or surface motivation and strategy. RESULTS: A multivariate analysis of variance determined that those in the control group were using the deep approach, whereas those in the ADHD group strongly favored the surface approach. Furthermore, ADHD participants preferred surface motive and surface strategy. A factor analysis of a study-habits questionnaire identified five categories, with collaborative learning approaching significant levels. CONCLUSION: Implications for guiding ADHD college students toward effective study strategies are discussed in light of their preference for surface approach, motive, and strategy.

Reaction time of motor responses in two-stimulus paradigms involving deception and congruity with varying levels of difficulty.

Deception research has focused on identifying peripheral nervous system markers while ignoring cognitive mechanisms underlying those markers. Cognitive theorists argue that the process of deception may involve such constructs as attentional capture, working memory load, or perceived incongruity with memory, while psychophysiologists argue for stimulus salience, arousal, and emotion. Three studies were conducted to assess reaction time (RT) in relation to deception, response congruity, and preparedness to deceive. Similar to a semantic verification task, participants evaluated sentences that were either true or false, and then made truthful or deceptive evaluations of the sentence's base truth-value. Findings indicate that deceptive responses have a longer RT than truthful responses, and that this relationship remains constant across response type and preparedness to deceive. The authors use these findings in preliminary support of a comprehensive cognitive model of deception.

Left hemispheric contributions to temporal perception: a resting electroencephalographic study.

Beta brain wave frequencies, theta brain wave frequencies, and interhemispheric transfer rates were investigated in individuals to explore components of time perception. Research suggests that the left hemisphere is highly involved in attention and language, which are important components of temporal processing mechanisms. Resting state electroencephalography was used to evaluate the relationship between right and left hemispheric brain wave frequencies and performance on a duration-discrimination task and an interhemispheric transfer rate task. A stepwise multiple regression was used to investigate the absolute spectral power of right minus left hemispheric activation for each frequency (alpha, beta, gamma, theta) at each of eight paired electrode locations onto d' data for a temporal discrimination task. Higher absolute spectral power in parietal and temporal left electrodes was predictive of better performance on the duration-discrimination task. Right-to-left interhemispheric transfer approached a significant correlation with performance on the duration-discrimination task. Our results indicate that sensitivity on a temporal task is positively correlated with beta and theta brain wave frequencies, and negatively correlated with right-to-left interhemispheric transfer rates. The current study provides support for a left hemispheric advantage for temporal processing; this provides further explanation of temporal processing mechanisms and where deficits may occur in clinical populations.

The effect of ipsilesional cues on line-bisection errors: the importance of predictive value.

Patients with unilateral neglect were tested on a line-bisection task in which vertical lines were added to the ipsilesional or contralesional end. During some blocks, these vertical lines accurately predicted the horizontal length of the line, while on other blocks the vertical lines had little predictive value. We found that much of the improvement for ipsilesional vertical bars can be explained by their ability to predict the extent of the horizontal line. These results suggest that the predictive value of a ipsilesional cue is responsible for the reduction in line-bisection errors noted by Halligan and Marshall [Neuropsychologia 32 (1994) 13]. This effect of the predictive ipsilesional cue may work in combination with the expanded attentional effects posited by the ipsilesional contraction model that they proposed.

Factor analysis of five adult ADHD self-report measures: are they all the same?

OBJECTIVE: To test the assumption in the research and assessment of ADHD symptoms that self-report scales measure the same underlying cognitive construct and that there is convergent validity among the scales. The present study specifically tested this assumption by analyzing the scores of 616 individuals on five ADHD self-rating scales using principal components analysis. METHOD: Participants completed five self-report scales widely used in the clinical and research communities: the CSS, the BADDS, the CAARS, the AADDES, and the WURS. RESULTS: Results show that while all scales were highly correlated and loaded onto a single factor solution, the WURS was differentiated from the other four scales best seen through a two factor solution. Therefore, the WURS may also measure other mental and emotional constructs independent from ADHD. Furthermore, participants that reported a previous diagnosis of ADHD scored significantly higher on all measures than those who did not. CONCLUSION: Since these scales are in strong agreement with one another in diagnosing ADHD, assessment becomes an issue of which scale is the least time-consuming and most pragmatic for the evaluator to use.

Resting electroencephalography correlates of pseudoneglect: an individual differences approach.

We conducted an exploratory study to examine the resting electroencephalography (EEG) correlates of pseudoneglect, a phenomenon wherein neurologically intact individuals show greater attentional bias toward the left side compared with the right side of space. We took the resting EEG of 21 college students for 5 min and then had them complete a computerized line perception task, during which we asked them to judge the midpoint of horizontal lines on the screen. We computed EEG asymmetry measures for theta, alpha, beta, and gamma frequency bands for each of eight locations (right electrode activity-left electrode activity in the analogous location) and separately regressed these onto the degree of pseudoneglect using stepwise multiple regression analyses. We found significant effects for gamma, theta, and beta bands at location F3/4, indicating greater tonic right midfrontal activation in this location. These findings show that individuals with generally greater right midfrontal resting activation across theta, beta, and gamma bands also demonstrate pseudoneglect during a line perception task. These results lend a novel finding to the pseudoneglect literature, namely an individual differences corollary to current active task observations in the field.

Contextual influences on rapid object categorization in natural scenes.

The current study aimed to investigate the effects of scene context on rapid object recognition using both behavioral and electrophysiological measures. Participants performed an animal/non-animal go/no-go categorization task in which they had to decide whether or not a flashed scene contained an animal. Moreover, the influence of scene context was manipulated either by retaining, deleting, or phase-randomizing the original scene background. The results of Experiments 1 and 2 showed that participants responded more accurately and quickly to objects appearing with their original scene backgrounds. Moreover, the event-related potential (ERP) data obtained from Experiment 2 showed that the onset latency of the frontal go/no-go ERP difference was delayed for objects appearing with phase-randomized scene backgrounds compared to objects appearing with their original scene backgrounds, providing direct evidence that scene context facilitates object recognition. Additionally, an increased frontal negativity along with a decreased late positive potential for processing objects presented in meaningless scene backgrounds suggest that the categorization task becomes more demanding when scene context is eliminated. Together, the results of the current study are consistent with previous research showing that scene context modulates object processing.

Psychophysiology and imaging of visual cortical functions in the blind: a review.

Imaging, transcranial magnetic stimulation, and psychophysiological recordings of the congenitally blind have confirmed functional activation of the visual cortex but have not extensively explained the functional significance of these activation patterns in detail. This review systematically examines research on the role of the visual cortex in processing spatial and non-visual information, highlighting research on individuals with early and late onset blindness. Here, we concentrate on the methods utilized in studying visual cortical activation in early blind participants, including positron emissions tomography (PET), functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation (TMS), and electrophysiological data, specifically event-related potentials (ERPs). This paper summarizes and discusses findings of these studies. We hypothesize how mechanisms of cortical plasticity are expressed in congenitally in comparison to adventitiously blind and short-term visually deprived sighted participants and discuss potential approaches for further investigation of these mechanisms in future research.

Spending of remuneration by subjects in non-treatment drug abuse research studies.

BACKGROUND: This study examines remuneration spending by drug-using participants in residential drug abuse research. METHODS: Ninety-four adult males who participated in residential, non-treatment drug abuse research studies earned remuneration based on length of stay and specific research procedures. Remuneration could be in cash after discharge or for in-kind purchases and bill payments. Spending of remuneration was extracted from charts and evaluated with multivariate analyses. RESULTS: Participants received average remuneration of 1,454 dollars, taking 59% in cash. Other categories included cigarettes (60.6% of subjects), toiletries (60.6%), clothing (54.3%), and housing (52.1%). Primary drug of abuse, total remuneration, monthly income, length of stay on the residential research unit, age, and education were significantly associated with in-kind remuneration choices. Less total remuneration, intoxication in the month prior to study, higher IQ, and non-white race were associated with taking more in cash. CONCLUSION: Residential drug abuse research participants prefer cash to in-kind research remuneration, and their choices reflected drug use and economic status.

The color of two alphabets for a multilingual synesthete.

Interviews with a multilingual synesthete (MLS), who experiences colored letters for Roman and Cyrillic alphabets and for digits, revealed stable synesthetic experiences over 2 1/2 - 5 years. Colors of Cyrillic letters were based on Roman letters. Four Stroop tests involving both types of letters showed that MLS was able to name print color faster if the colors matched her synesthetic colors, showing that synesthesia is automatic. Letter-naming times for blocks of color were slower than those of actual letters, supporting unidirectionality of synesthesia. Stroop tests with Roman, but not Cyrillic, letters showed MLS acquired new temporary letter-color pairings and her color-naming times for these were not different from those for her original synesthetic colors.