A new mathematical model of short-term synaptic plasticity (STP) at the Schaffer collateral is introduced. Like other models of STP, the new model relates short-term synaptic plasticity to an interaction between facilitative and depressive dynamic influences. Unlike previous models, the new model successfully simulates facilitative and depressive dynamics within the framework of the synaptic vesicle cycle. The novelty of the model lies in the description of a competitive interaction between calcium-sensitive proteins for binding sites on the vesicle release machinery. By attributing specific molecular causes to observable presynaptic effects, the new model of STP can predict the effects of specific alterations to the presynaptic neurotransmitter release mechanism. This understanding will guide further experiments into presynaptic functionality, and may contribute insights into the development of pharmaceuticals that target illnesses manifesting aberrant synaptic dynamics, such as Fragile-X syndrome and schizophrenia. The new model of STP will also add realism to brain circuit models that simulate cognitive processes such as attention and memory. The hippocampal processing loop is an example of a brain circuit involved in memory formation. The hippocampus filters and organizes large amounts of spatio-temporal data in real time according to contextual significance. The role of synaptic dynamics in the hippocampal system is speculated to help keep the system close to a region of instability that increases encoding capacity and discriminating capability. In particular, synaptic dynamics at the Schaffer collateral are proposed to coordinate the output of the highly dynamic CA3 region of the hippocampus with the phase-code in the CA1 that modulates communication between the hippocampus and the neocortex.

Trigeminal neuralgia is a painful neuralgia with a complicated pathology that is not clearly understood. Due to the ambiguity of the condition, patients often have to search for medical providers that specialize in trigeminal neuralgia, and even with the guidance of a specialist, some patients do not respond well to treatment.1 Despite the uncertainty surrounding the specifics of the disease, there are treatments available that can provide some level of pain relief for patients suffering from this disorder. When a patient does not respond well to medical therapy, surgery can be the next appropriate step in patient care management.2 However, while surgery can provide significant pain relief for patients who qualify, non-surgical treatments are needed during the interim, in the event of relapse, or for individuals who do not qualify for surgery. Cognitive behavioral therapy (CBT) is a well-researched treatment for chronic pain resulting from various diseases and disabilities.3 A systematic literature review was performed to identify if CBT decreases pain and improves the quality of life for patients diagnosed with classical, secondary, or idiopathic trigeminal neuralgia. More research is needed, but there is promising evidence in the literature that cognitive behavioral therapy can be useful for patients with trigeminal neuralgia to help them cope with their pain. In addition, there may be evidence that, while somewhat effective alone, cognitive behavioral therapy may be more effective in conjunction with another treatment such as medication. These results are encouraging for patients suffering with the chronic pain of trigeminal neuralgia, and future studies should further investigate the benefits of cognitive behavioral therapy for patients with trigeminal neuralgia.

INTRODUCTION: Reaction time may be broadly defined as the time between stimulus presentation and a response. Analysis of reaction time in terms of rate of force development (RFD), peak force, and surface electromyography (EMG) may help bridge the gaps in knowledge pertaining to the neuromuscular system's role in reaction time. The purpose of the present study was to identify predictors of reaction time using digital hand grip dynamometry and EMG. It was hypothesized that RFD and rate of EMG rise (RER) at the onset of a contraction would correlate with reaction time. METHODS: For grip testing, participants were instructed to squeeze a handheld dynamometer with the right hand "…as hard and fast as possible" for 5 seconds upon hearing a "beep" from the computer. A total of 5 attempts were performed, with 1-minute rest periods. Bipolar surface EMG signals were detected from the right first dorsal interosseous (FDI) and flexor carpi radialis (FCR) muscles throughout grip testing. Bivariate correlations (Pearson r) were used to examine the statistical associations. The 95% confidence interval (CI) for each Pearson r was also computed. An alpha level of p ≤ 0.05 was used to reject the null hypothesis. RESULTS: Significant correlations were observed between reaction time and all other measures of grip force (r = -0.507 to -0.557, p= 0.016 to 0.042), except for time until peak force (r = 0.029, p = 0.915). As FDI EMG amplitude increased reaction time decreased (r = -0.664, p = .005). CONCLUSION: Many of the grip force variables were significantly associated with reaction time. Peak force and rapid force variables showed significant correlations with reaction time. While no significant correlations for any of the FDI RER or FCR variables were found, EMG amplitude from the FDI presented the strongest bivariate correlation. As FDI EMG amplitude, peak force, and rapid force variables increased reaction time decreased. These findings give some insight into the neuromuscular system's role in hand grip tasks and help broaden the current understanding of variables that may be used to assess or improve reaction time in the clinical setting.

The aim of this study was to investigate the relationship between thigh intramuscular fat (intraMF) and intermuscular fat (IMF) with quadriceps and hamstrings power and physical performance in women (n=20) with clinical, radiographic knee osteoarthritis (OA). Secondarily, we investigated the correlation between thigh and calf fat volumes, and the agreement between 3.0T and 1.0T MRI for quantifying fat. The thigh and calf of the symptomatic leg were scanned using 3.0T MRI with the IDEAL sequence, and fat separated images were analyzed using semi-automated software to quantify intraMF, IMF and muscle. The calf was also scanned using 1.0T MRI with a Fast Spin Echo (FSE) sequence. Knee extensor and flexor isokinetic power was measured at 20% and 40% of individuals’ maximum voluntary isometric contraction (MVIC) torque, and surface electromyography (EMG) measured activation. We found no relationship between quadriceps or hamstrings intraMF and knee extensor or flexor power, respectively. In addition, there were no relationships between intraMF and performance-based tests. There was a correlation between thigh and calf intraMF (r=0.759; p=0.001) and a trend toward a correlation in IMF (r=0.436; p=0.055). There was agreement and a correlation between calf intraMF (r=0.779; p=0.001) and IMF (r=0.956; p=0.001) using 3.0T and 1.0T MRI. There is disagreement about the relationship of intraMF and quadriceps strength, although studies have found that intraMF is related to decreased physical performance. The importance of calf fat subsets in physical performance of individuals with OA should be further investigated. Power analysis demonstrated a sample size (n=91) is recommended for future investigations of intraMF and power in OA. / Thesis / Master of Science in Medical Sciences (MSMS)

Perceptions of benefits of speech therapy, success of therapy across clinical settings, reasons for returning to therapy, client-clinician relationships, and clinicians' competency were assessed in 57 participants (47 men, 10 women; M age = 34 yr.) trying a new therapy. A majority of respondents had cumulatively five or more years in therapy and at least two stuttering therapies. Respondents rated university or hospital settings as more successful than services in public schools. 70% of the respondents noted difficulty communicating basic needs; they blamed themselves for inability to maintain posttherapeutic gains while perceiving their clinicians to be competent and attentive ? although 47% of the respondents had minimal to no contact with their therapist after therapy.

Summary Objectives/Hypotheses To assess the utility of a targeted voice hygiene (VH) program compared to VH plus voice training intervention (VH+VT) for the prevention and treatment of voice problems in student teachers. Study Design Prospective, randomized. Methods Thirty-one student teachers with low (good) and high (poor) voice handicap index (VHI) scores in Pittsburgh and Hong Kong were randomly assigned to (1) a targeted, individually tailored VH program, (2) the VH program plus resonant VT (VH+VT), or (c) a control group. Participants assigned to intervention groups were monitored for their adherence to their programs for their first 4 weeks of student teaching. VHI data were collected again 4 weeks postintervention (both sites) and 8 weeks postintervention, following a no-contact washout period (Pittsburgh). Results Descriptive data analysis indicated that across both sites, for initially healthy participants, the VH program was sufficient to prevent worsening of VHI scores that occurred in all control participants over the first 4–8 weeks of student teaching. The addition of VT did not consistently enhance protective benefits over VH alone. In contrast, for participants with initially poor VHI scores, the VH program failed to produce VHI benefits over the control condition. The addition of VT was required to optimize results for that cohort. Conclusions Preliminary data suggest that a minimalist, individually tailored VH program may be sufficient to prevent voice problems from teaching in healthy student teachers. However, for student teachers with existing voice problems, VT may be required to optimize results of intervention.

The recovery from prior stimulation of the compound action potential (CAP) was measured using a forward masking stimulus paradigm in four normal-hearing, human subjects. The CAP was recorded using a wick electrode placed on the tympanic membrane. The effects of a 4000-Hz, 97-dB SPL conditioning stimulus on CAP amplitude in response to a 4000-Hz probe were measured as a function of conditioner–probe interval for three probe levels. The normalized probe response amplitude was completely recovered to the control values at an average conditioner–probe interval of 1359 ms, similar to that observed in chinchilla (Relkin, E.M., Doucet, J.R., Sterns, A., 1995. Recovery of the compound action potential following prior stimulation: evidence for a slow component that reflects recovery of low spontaneous-rate auditory neurons, Hear. Res. 83, 183–189). The present results are interpreted as a consequence of the slow recovery of low spontaneous-rate (SR), high threshold neurons from prior stimulation (Relkin, E.M., Doucet, J.R., 1991. Recovery from prior stimulation. I: Relationship to spontaneous firing rates of primary auditory neurons. Hear. Res. 55, 215–222) and may provide indirect physiological evidence for the existence of a class of low-SR auditory neurons in humans.

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No description available.

In this study 538 children composed 1 oral and 1 written fictional story in both 2nd and 4th grades. Each child represented 1 of 4 diagnostic groups: typical language (TL), specific language impairment (SLI), nonspecific language impairment (NLI), or low nonverbal IQ (LNIQ). The stories of the TL group had more different words, more grammatical complexity, fewer errors, and more overall quality than either language-impaired group at either grade. Stories of the SLI and LNIQ groups were consistently stronger than were those of the NLI group. Kindergarten children with language impairment (LI) whose standardized test performance suggested normalization by 2nd grade also appeared to have recovered in storytelling abilities at that point. By 4th grade, however, these children's stories were less like the children with TL and more like those of children with persistent LI than they had been in 2nd grade. Oral stories were better than written stories in both grades, although the greatest gains from 2nd to 4th grade were generally made on written stories. Girls told stronger stories than did boys at both grades, regardless of group placement. It is concluded that story composition tasks are educationally relevant and should play a significant role in the evaluation of children with developmental LI.