November 11th, 2009

Uh-oh! I Made a Mistake: ERP correlates of Error Detection in a Semantic Categorization Task

Michal Balass

The error-related negativity (ERN) is a negative deflection in the ERP record elicited 0 to 160ms post-response related to conscious error detection. The ERN is regarded as the brain’s “Uh-Oh!” signal when a conscious error has been made. Studies have shown evidence for the ERN in verbal perception tasks (Ganushchak & Schiller, 2008), and also indicated its usefulness for showing differences in error detection related to reading skill (Horowitz-Kraus & Breznitz, 2008). However, there are not many studies published to date showing an ERN response to higher level processing; for example, semantic processing. In this study, we used a time-pressured semantic categorization task in an attempt to elicit errors to simple category decisions (e.g., is Africa a country?). In this talk, I will present evidence showing greater ERN negativity at approximately 100ms post-response to incorrect responses than for correct responses. Further, I will discuss correlational analyses showing that ERN negativity may be related to individual differences measures of reading skill.

November 4th, 2009

Adolescence without the Fun: Examining Reward Function in Youth with Depression

Erika E. Forbes

In the search for neural substrates of depression, some recent work has suggested that the disruption of reward processing occurs as part of the essential pathophysiology of the disorder. Depression has long been conceptualized as a disorder of dysregulated positive affect and unusual reward function, and affective neuroscience findings have begun to support this perspective. Furthermore, taking a developmental perspective is critical because the onset of depression typically occurs during adolescence, and altered reward function during adolescence is a predictor of future depression. This presentation will describe neuroimaging, behavioral, and subjective studies on reward function in adolescent depression. These studies were conducted using monetary reward functional MRI paradigms, performance on reward-related decision paradigms, and experience sampling of positive affect. Together, the results of this set of studies indicate that adolescents with depression exhibit less striatal reactivity to reward, are less behaviorally sensitive to reward, and experience lower intensity of reward-related affect. Furthermore, preliminary findings suggest that reward-related brain function predicts response to treatment in adolescents with depression. The presentation will emphasize the importance of placing adolescent depression in a developmental context, examining brain-behavior associations, and using multimethod approaches to capturing affective processes.

October 28th, 2009

Examining Attention Allocation in Gaze-Contingent Visual Search Tasks Using Diffusion Models

Polina Vanyukov

In two eye-movement experiments (presented at the brown bag last fall) we examined whether attention is allocated serially or in parallel during three visual search tasks using 2-8 character arrays subtending two degrees of visual angle: (1) single-feature detection; (2) conjunctive-feature detection; and (3) ordered-feature detection. In the first experiment, participants’ eye movements were recorded; in the second, a gaze-contingent paradigm was used to evince covert attentional shifts. In this follow-up work, random-walk (diffusion) models of parallel and serial search (Thornton & Gilden, 2007) were fit to the data from the gaze-contingent study to determine which type of search best accounts for the patterns of reaction times and error rates in these tasks. The results from the computational modeling suggest that single-feature and conjunction-feature detection tasks are better described by a parallel model of visual search. Ordered-feature detection task, however, was well approximated by both serial and parallel (limited capacity) models of visual search. Implications for attention allocation during reading are discussed.

October 21st, 2009

Individual Differences in Patterns of Reading

Jessica Nelson

A large database of reading test scores for over 2000 participants was analyzed using a factor analysis to determine the main dimensions along which readers vary in skill. A smaller subset of these participants had their eye movements monitored while they read paragraphs collected mostly from online news stories or informational articles. Individual differences in patterns of eye movements during reading, including regression and fixation statistics, will be related to the dimensions of reading skill obtained from the factor analysis of reading scores.

October 14th, 2009

Looking for Failure and Success: Factors that Determine Dual-Tasking Performance

Nicole M. Hill

Although humans frequently engage in dual-tasking, generally performance is suboptimal.  When component tasks are initially performed simultaneously, accuracy decreases relative to single-task competency producing a dual-task deficit.  Single-task training does not readily transfer to dual-tasking; this the case even when component tasks are both automatically processed (Schneider & Hill, 2006).  Although dual-task practice is a necessary it is not sufficient for operating without a deficit.  Schneider and Fisk (1982) trained participants to perform a dual-task comprised of an attention demanding task and an automatic task.  The dual-task deficit was attenuated after substantial practice but only when the attention demanding task was prioritized.  Hill and Schneider attempted to train participants on a dual-task which was also comprised of an attention demanding task and an automatic task.  Despite instructing participants to prioritize the attention demanding task, the majority of the participant’s performance was sub par relative to their single-task detection rate.  In contrast, failure only rarely occurs when both tasks are automatic, suggesting that successfully timesharing an attention demanding task requires more than practice and appropriate task prioritization.  After replicating Schneider and Fisk’s result a series of follow up studies were conducted to determine which factor(s) determine dual-task learning.  Preliminary results of these studies will be presented.

October 7th, 2009

Professional Development: Panel on the Job Search Process
Jennifer Russell, Kathryn Rocklein, Timothy Nokes, and Susannah Paletz

The panel will offer their insights, advice and memories of the job search process. Come prepared with questions!

September 23rd, 2009

Elements of a Job Application in Psychology
Natasha Tokowicz

We will discuss the various types of academic jobs available in psychology. We will also talk about the types of application materials that are expected for each type of job (e.g., research statement, teaching statement). A brief overview of each component will be given with the goal of helping students to prepare these materials when necessary.

September 9, 2009

Mapping Brain Circuits with High Definition Fiber Tracking (HDFT) for Cognitive Neuroscience and Medical Imaging
Walter Schneider (with Sudhir Pathak, Jeff Phillips, Juan Fernandez-Miranda & Frank Yeh)

In the last 60 days we have made a dramatic advance in fiber tracking we call High Definition Fiber Tracking (HDFT). The technology provides in-vivo imaging allowing tracking of 300,000 fiber tracts throughout the brain with clear identification of the fiber contacts and millimeter resolution of connectivity and quantification of relative connectivity. The HDFT images are likely the highest fidelity images ever collected of the in-vivo human brain and on a par with micro dissection. HDFT allows tracing of circuits such as language processing, executive system, and affect and following individuals through development or disease process. We are applying HDFT in neurosurgerical planning and diagnosis of traumatic brain injury. Pittsburgh has a leading edge of this technology that can be applied to many areas of study including a proposal to map the Human Connectome. This talk introduces the technology and illustrates how it can be applied to basic issues such as mapping the connectivity of the Cognitive Control Net (CCN) and the Human Connectome. A goal of the talk is to seek collaborative opportunities to exploit the technology in Pittsburgh.