Graduate Student Seminar Scheduled for November 12

The Fall 2008 Beckman Institute Graduate Student Seminar series continues on Wednesday, November 12. The seminar will feature three short talks from graduate students Chun Yu Tse, Ben Blaiszik, and Michelle W. Voss. 

The Beckman Institute Graduate Student Seminar Series presents the work of outstanding graduate students working in Beckman research groups. The seminar starts at Noon in Beckman Institute Room 1005 and is open to the public. Lunch will be served.

Imaging Dynamics of the Brain during Language Processes – An Event-related Optical Signal (EROS) study
Chun Yu Tse

Since most brain-imaging techniques provide either superior temporal (e.g. event-related potentials - ERPs) or spatial resolution (functional magnetic resonance imaging - fMRI), but not both, different aspects of language comprehension processes need to be investigated with different methods. The present study used a recently developed brain-imaging technique, the event-related optical signal (EROS), which combines excellent spatial and temporal resolutions, to study the interactions of left inferior frontal and superior temporal cortices (IFC and STC) during language comprehension. Participants were presented with semantically or syntactically anomalous sentences and were required to judge their acceptability. The EROS response to semantically anomalous words showed increased activity in the temporal cortex, followed by IFC activity. Syntactically anomalous words evoked a similar sequence, with a temporal-lobe EROS response, followed by frontal activity. However, the STC activity corresponding to a semantic anomaly was more ventral than that corresponding to a syntactic anomaly. These data suggest that activation related to anomaly processing in sentences proceeds from temporal to frontal brain regions for both semantic and syntactic anomalies. This is the first study to apply EROS to the investigation of the temporal and spatial dynamics of language processing, and thus demonstrates its feasibility in this domain.

Interfacial Self-healing for Advanced Composites
Ben Blaiszik

To observe self-healing along an interface, a method was developed for sequestration of healing agent filled microcapsules and catalyst to the reinforcement-matrix interface. A custom-made single fiber testing frame was built, and mounted under an optical microscope to provide simultaneous load-displacement and optical observation of the crack front propagation during debonding and subsequent healing events. In this work, we show initial results from a combination of microbond and pullout tests characterizing interfacial healing in a glass fiber-epoxy composite model system. Since microcracking and interfacial failure of reinforcing fibers is one of the key failure mechanisms in composite materials, healing this damage an early stage may allow for a substantial increase in expected lifetime by preventing catastrophic growth of smaller flaws.

Differential exercise effects on the brain and cognition for preadolescent children and elderly adults
Michelle W. Voss

Recent research has shown that increased aerobic fitness is associated with better cognitive performance for preadolescent children and elderly adults.  Given that childhood obesity and inactivity are on the rise, and that the number of Americans diagnosed with dementia is expected to more than double over the next 20 years- it is an important public health initiative to understand what factors contribute to the development and longevity of a healthy mind.  While previous research with humans has used non-invasive functional magnetic resonance imaging (fMRI) to elucidate changes in brain activity in elderly adults as a function of fitness, this has not yet been done with preadolescent children.  In this talk I will present data that supports the positive association between aerobic fitness, functional brain activity, and cognition, for elderly adults.  Further, I will present evidence that suggests the nature of the effects of exercise on the brain is altered for preadolescent children compared to elderly adults.  These data have implications for characterizing the functional development, and potential moderators, of the maturing brain.  Moreover, the differential effects of exercise on the brain for the two age groups provide additional information with which to understand the neurobiological mechanisms for the fitness-cognition link.