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.     

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.     

The use of an escape contingency and a token economy to increase food acceptance

Escape (termination of a meal) and token-based differential reinforcement of alternative behavior were used as reinforcement to increase acceptance of food. Using a changing criterion design, the number of bites accepted and consumed was gradually increased to 15 bites per meal. These data suggest that, in some cases, escape may be a potent reinforcer for food acceptance.     

A multilevel analysis of the interpersonal behavior of socially anxious people

We investigate the interpersonal behavior of socially anxious (SA) and non-socially anxious (NSA) individuals at three different levels of analysis, focusing on the dimensions of warmth and dominance. Study 1 examines self-reported general interaction styles, Study 2 explores behavior occurring within the context of a single interaction, and in Study 3 we focus on the performance of a single conversational act (a disagreement). Studies 1 and 2 adopt the framework of Interpersonal Circumplex Theory (IPC; Kiesler, 1983), which is well suited for studying trait-level and interaction-level social behaviors, while Study 3 is grounded in Politeness Theory (PT; Brown & Levinson, 1987), which can be used to analyze individual acts at the microstructural level. The potential mutual relevance of PT and IPC is also discussed.     

Gait transitions are not dependent on changes in intralimb coordination variability

The HKB model (H. Haken, J. A. S. Kelso, & H. Bunz, 1985) of coordination has been predominantly applied to upper extremity stationary movements. It predicts increased variability of relative phase before a transition and a decrease after a transition. The authors of the present study extended the intralimb lower extremity locomotive research of F. J. Diedrich and W. H. Warren (1995) by conducting continuous treadmill walk-to-run and run-to-walk trials with 10 participants. Standard deviation of knee-ankle and hip-ankle relative phase did not increase before walk-to-run and run-to-walk transitions, and there was no decrease in knee-ankle relative phase variability after either transition. The results of this study did not provide strong support for application of the variability predictions of the HKB model of coordination to lower extremity intralimb coordination during gait transitions.     

CHALLENGES FACING FEMALE DOCTORAL STUDENTS AND RECENT GRADUATES

Although increasing the numbers of women and minority faculty in academia is a widely held goal, their numbers remain small. The presence of women and minorities decreases disproportionately at each ascending rung of the academic ladder. This investigation identified factors potentially contributing to attrition in White and non-White women at a critical stage in their careers: as doctoral candidates and recent graduates. Two-hundred and twenty-four women in the life sciences, social sciences, and the humanities described their most pressing professional and personal concerns and offered suggestions for changes in their fields and in academia more generally. Independent raters coded responses by thematic content. Differences in responses by field, educational status, and minority status were examined. The most frequently cited concerns involved practical issues such as finding employment, financial stability, and developing professional expertise, revealing wide-spread concerns about a competitive academic climate. Suggestions included modifications in professional conduct, the employment and pay structure, and training.