Impaired frontostriatal cognitive functioning following posteroventral pallidotomy in advanced Parkinson's disease

We investigated the long-term effects of posteroventral pallidotomy on tests sensitive to the functional integrity of frontostriatal neural systems in a sample of 11 patients with advanced Parkinson's disease (PD). Patients were assessed within 1 month prior to surgery and at 12 months following pallidotomy. Changes in outcome measures were compared to a control sample of equally performing PD patients receiving nonsurgical medical management assessed over a 12-month period. Measures of cognitive abilities sensitive to frontostriatal functional integrity tested psychomotor processing speed, executive components of working memory, and reasoning. Additional tests of general mental status and semantic memory ability were utilized to assess the specificity of the effect of pallidotomy on cognitive function. Significant declines in performance on all measures sensitive to frontostriatal integrity were found for the surgery group but not the PD control group. No significant changes in performance were found on the measures of general mental status or semantic memory for either the surgery or PD control samples. These results suggest that the posteroventral pallidotomy selectively impairs performance on tests of frontostriatal cognitive abilities.     

Neural synchrony in stochastic resonance, attention, and consciousness.

We describe briefly three of our lab's ongoing projects studying the role of neural synchrony in human perception and cognition. These projects arise from two main interests: the role of noise both in human perception and in neural synchrony, and neural synchrony as a basis for integration of functional modules in the brain. Our experimental work on these topics began with a study of the possibility that noise-influenced neural synchrony might be responsible for the fact that small amounts of noise added to weak signals can enhance their detectability (stochastic resonance). We are also studying the role of neural synchrony in attention and consciousness in several paradigms. On the basis of our own and related work by others, we conclude that (1) neural synchrony plays an important role in the integration of functional modules in the brain and (2) neural synchrony is profoundly affected and possibly regulated, in part, by the "noisiness" of the brain.     

Harm, intent, and the nature of aggressive behavior: measuring naturally occurring aggression in barroom settings

The research goals were to use the constructs of harm and intent to quantify the severity of aggression in the real-world setting of the bar/club, to describe the range of aggressive behaviors and their relationship to harm and intent, and to examine gender differences in the form and severity of aggression. Systematic observations were conducted by trained observers on 1,334 nights in 118 bars/clubs. Observers documented a range of aggressive acts by 1,754 patrons in 1,052 incidents, with many forms of aggression occurring at more than one harm and intent level. Women used different forms of aggression, inflicted less harm, and were more likely to have defensive intent compared with men. Implications of the findings for research and measurement of aggression and applications to preventing aggression and violence are discussed.     

Detecting true lies: police officers' ability to detect suspects' lies

Ninety-nine police officers, not identified in previous research as belonging to groups that are superior in lie detection, attempted to detect truths and lies told by suspects during their videotaped police interviews. Accuracy rates were higher than those typically found in deception research and reached levels similar to those obtained by specialized lie detectors in previous research. Accuracy was positively correlated with perceived experience in interviewing suspects and with mentioning cues to detecting deceit that relate to a suspect's story. Accuracy was negatively correlated with popular stereotypical cues such as gaze aversion and fidgeting. As in previous research, accuracy and confidence were not significantly correlated, but the level of confidence was dependent on whether officers judged actual truths or actual lies and on the method by which confidence was measured.     

False reports of childhood events in appropriate interviews

The present study employed the "parental misinformation" paradigm to examine whether individuals report false events from their childhood even when they are interviewed in an appropriate manner by a trained interviewer. Each participant was interviewed on three occasions. By the final interview, one participant produced a "full" report, and six participants produced "partial" reports, of childhood events that did not occur. Although participants reported perceiving greater pressure to report the false events than the real events, independent judges' ratings of social pressure in the interviews did not differ as a function of what type of event participants were being asked about. Participants also reported higher confidence in their parents', compared to their own, recall of events from their childhood. False reports were also positively correlated with scores on both the full and the revised versions of the Dissociative Experiences Scale, and negatively correlated with score on the Self-Monitoring scale. These results indicate that, despite being interviewed in an appropriate manner by a trained interviewer, some participants will falsely report events from their childhoods.     

Adolescent Girls’ and Boys’ Science Peer Relationships and Perceptions of the Possible Self as Scientist

Girls tend to have less peer support for their science interests than do boys, which may contribute to gender differences in science motivation. The effect of science peer relationships on adolescents visions of their possible personal future lives as scientists was studied in 161 female and 163 male gifted high school students who participated in summer science enrichment programs. Student reports of having positive science peer relationships were associated with more positive expectations of the possible personal self as scientist prior to the programs, and both program-related and nonprogram-related science peer relationships were associated with changes in the possible self at posttesting and at 6 month follow-up. These relations held for both male and female students. At follow-up, girls reported a stronger social niche with fellow program participants and stronger science peer relationships than did boys. Implications of the findings are discussed within the larger gendered societal context for science achievement.     

Question asking and eye tracking during cognitive disequilibrium: Comprehending illustrated texts on devices when the devices break down

The PREG model of question asking assumes that questions emerge when there is cognitive disequilibrium, as in the case of contradictions, obstacles, and anomalies. Participants read illustrated texts about everyday devices (e.g., a cylinder lock) and then were placed in cognitive disequilibrium through a breakdown scenario (e.g., the key turns but the bolt does not move). The participants asked questions when given the breakdown scenario, and an eyetracker recorded their fixations. As was predicted, deep comprehenders asked better questions and fixated on device components that explained the malfunction. The eye fixations were examined before, during, and after the participants' questions in order to trace the occurrence and timing of convergence on faults, causal reasoning, and other cognitive processes.     

Relationships among compulsive hoarding, trauma, and attention-deficit/hyperactivity disorder

The current study investigated aspects of post-traumatic stress disorder and attention deficit/ hyperactivity disorder (ADHD) among hoarders. Compared to a sample of 36 controls, hoarders (n=26) reported a significantly greater number of different types of trauma, more frequent traumatic experiences, more symptoms of inattention, hyperactivity, and greater comfort derived from possessions. These findings are consistent with previous reports of extensive comorbidity associated with hoarding behaviors, and may reflect the potential usefulness of assessing PTSD and ADHD symptoms at the outset of hoarding treatments, as well as considering alternative pharmacological interventions.     

Online versus offline processing of visual feedback in the control of movement amplitude

Researchers have suggested that visual feedback not only plays a role in the correction of errors during movement execution but that visual feedback from a completed movement is processed offline to improve programming on upcoming trials. In the present study, we examined the potential contribution of online and offline processing of visual feedback by analysing spatial variability at various kinematic landmarks in the limb trajectory (peak acceleration, peak velocity, peak negative acceleration and movement end). Participants performed a single degree of freedom video aiming task with and without vision of the cursor under four criterion movement times (225, 300, 375 and 450 ms). For movement times of 225 and 300 ms, the full vision condition was less variable than the no vision condition. However, the form of the variability profiles did not differ between visual conditions suggesting that the contribution of visual feedback was due to offline processes. In the 375 and 450 ms conditions, there was evidence for both online and offline control as the form of the variability profiles differed significantly between visual conditions.