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- Creators: Barrett, The Honors College
- Creators: Dixon, Maria
- Resource Type: Text
- Status: Published
The neurobiology of sentence comprehension: an fMRI study of late American Sign Language acquisition
The distinctions between the neural resources supporting speech and music comprehension have long been studied using contexts like aphasia and amusia, and neuroimaging in control subjects. While many models have emerged to describe the different networks uniquely recruited in response to speech and music stimuli, there are still many questions, especially regarding left-hemispheric strokes that disrupt typical speech-processing brain networks, and how musical training might affect the brain networks recruited for speech after a stroke. Thus, our study aims to explore some questions related to the above topics. We collected task-based functional MRI data from 12 subjects who previously experienced a left-hemispheric stroke. Subjects listened to blocks of spoken sentences and novel piano melodies during scanning to examine the differences in brain activations in response to speech and music. We hypothesized that speech stimuli would activate right frontal regions, and music stimuli would activate the right superior temporal regions more than speech (both findings not seen in previous studies of control subjects), as a result of functional changes in the brain, following the left-hemispheric stroke and particularly the loss of functionality in the left temporal lobe. We also hypothesized that the music stimuli would cause a stronger activation in right temporal cortex for participants who have had musical training than those who have not. Our results indicate that speech stimuli compared to rest activated the anterior superior temporal gyrus bilaterally and activated the right inferior frontal lobe. Music stimuli compared to rest did not activate the brain bilaterally, but rather only activated the right middle temporal gyrus. When the group analysis was performed with music experience as a covariate, we found that musical training did not affect activations to music stimuli specifically, but there was greater right hemisphere activation in several regions in response to speech stimuli as a function of more years of musical training. The results of the study agree with our hypotheses regarding the functional changes in the brain, but they conflict with our hypothesis about musical expertise. Overall, the study has generated interesting starting points for further explorations of how musical neural resources may be recruited for speech processing after damage to typical language networks.
We describe a secondary analysis of an in vitro experiment that supports the capabilities of a relatively new imaging technique known as functional Magnetic Resonance Electrical Impedance Tomography (fMREIT) to detect conductivity changes in neural tissue caused by activity. Methods: Magnetic Resonance (MR) phase data of active Aplysia ganglia tissue in artificial seawater (ASW) were collected before and after exposure to an excitotoxin using two different imaging current strengths, and these data were then used to reconstruct conductivity changes throughout the tissue. Results: We found that increases in neural activity led to significant increases in imaged conductivity when using high imaging currents, but these differences in conductivity were not seen in regions that did not contain neural tissue nor in data where there were no differences in neural activity. Conclusion: We conclude that the analysis presented here supports fMREIT as a contrast technique capable of imaging neural activity in live tissue more directly than functional imaging methods such as BOLD fMRI.
The goal of the research is to assist Barrett Honors students at Arizona State University by generating a mindset that embraces feelings of stress rather than avoiding it. After data collection was complete, the researchers created a valuable and necessary field guide for ASU Barrett Faculty to provide for incoming students. The present study has been compiled to prove the importance of reframing one's perception of stress as an aid, reducing one's “symptomatic” perception of stress and experiencing life's stresses as challenges, and to cease living in a constant unhealthy state of fight or flight. The main research questions are: What is the average perceived stress level of Barrett Honors students and what information can ASU further provide incoming Barrett students that will alleviate overall perceived stress levels based on the data collection and field guide generated from the present study? The basis of the present study began with a survey compiled of demographic questions, questions relating to the Human Event (HE - a required honors course), and lastly the Perceived Stress Scale (PSS) developed by Sheldon Cohen, Tom Kamarck, and Robin Mermelstein, with slight modification for students relating to their perception of stress over the last semester. After survey responses were concluded, it was determined that the average perceived stress score among honors students was 18.57, shockingly lower than what was previously thought. The overall results of the PSS survey indicate that Barrett students are moderately stressed, disproving the researchers initial hypothesis that honors students perceived stress scores would be considered high on the PSS. The results did provide researchers with enough data to compile an incoming Barrett student field guide based on desired information reported in the survey. A discussion of the results explores the purpose of how the present study can be used in helping students with perceived stress, interpretations and significance of the data, correlation between academic success and perceived stress, major contributions to the study, and limitations and recommendations for future research.