Faculty Bibliography

Human olfaction is sensitive but poorly encoded by language. A new study comparing horticulturalists and hunter-gatherers suggests that the strength of odor language is dependent on life-style. This work may stimulate olfactory research at the crossroads between biology and culture.

Transcranial electric stimulation is a non-invasive tool that can influence brain activity; however, the parameters necessary to affect local circuits in vivo remain to be explored. Here, we report that in rodents and human cadaver brains, ~75% of scalp-applied currents are attenuated by soft tissue and skull. Using intracellular and extracellular recordings in rats, we find that at least 1 mV/mm voltage gradient is necessary to affect neuronal spiking and subthreshold currents. We designed an 'intersectional short pulse' stimulation method to inject sufficiently high current intensities into the brain, while keeping the charge density and sensation on the scalp surface relatively low. We verify the regional specificity of this novel method in rodents; in humans, we demonstrate how it affects the amplitude of simultaneously recorded EEG alpha waves. Our combined results establish that neuronal circuits are instantaneously affected by intensity currents that are higher than those used in conventional protocols.

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Objectives: To report the preliminary results of the GLOMSAR survey for MSA. Background: Multiple system atrophy (MSA) is a rare fatal synucleinopathy characterized by Parkinsonian, pyramidal, cerebellar, and autonomic features in any combination. The GLObal MSA Registry (GLOMSAR) was established as an online contact registry for patients with MSA. Methods: Members of the Autonomic Disorders Consortium developed a web-based questionnaire comprising of 40-item with yes/no questions to evaluate the chronology and full spectrum of symptoms of MSA. GLOMSAR registrants were contacted by email on April 26 2017 and the survey was administered by the NIH's Rare Diseases Clinical Research Network (RDCRN). Results: Within 7 days, 155 registrants with MSA completed all 40 questions. Mean age was 62 years (range 30-92) and 58% were male. Frequent presenting symptoms were difficultly moving (28%), trouble with blood pressure or urination (23%), REM sleep behavior disorder (i.e., dream reenactment 23%) and falls (14%). Sixty-eight percent had been treated with levodopa and 30% experienced some benefit from it. Fifty-five percent reported using a wheelchair. Urinary incontinence was present in 65 and 30% required intermittent or indwelling urinary catheterization. Constipation occurred in 78%. Visual problems were reported in 65%. Of men, 91% reported erectile dysfunction; of women, 65% reported decreased genital sensation. Other findings included a high prevalence of depression (59%), hallucinations (21%) and a history of head trauma/concussion (22%). Conclusion: The GLOMSAR contact registry and web-based MSA survey are feasible ways to reach patients with MSA. This may be useful to support clinical research in this rare disease

Background: Depressive symptoms are common in patients with multiple system atrophy (MSA). We aimed to determine the prevalence of depression in MSA and its impact on quality of life and disease progression. Methods: MSA patients enrolled in a natural history study to determine the natural progression of disease. Patients completed psychiatric (Zung Depression scale, Spielberg's anxiety scale and Body vigilance scale) and autonomic (OHQ, COMPASS, UMSARS-I and II, SCOPA-Autonomic and SF36 Quality of life scale) rating scales, and underwent autonomic and cardiovascular assessments at baseline, and then followed at regular intervals for repeat assessments. Results: Forty-five MSA patients (mean age 61.8 years, 4.3 years disease duration) were included. Thirty patients (67%) scored as having depression on the Zung depression scale (15 mild, 13 moderate, and 2 severe). Seventy-three percent had orthostatic hypotension (OH). Depressed patients had higher trait/state anxiety and body vigilance scores than non-depressed patients. Depressed patients had significantly higher OHQ scores on each of the 6 OHSA items and each of the OHDAS items (OH interference with activities of standing and walking). Trait-anxiety and depression correlated with OHSA and OHDAS items. Depressed patients reported greater OHQ scores for the same amount of blood pressure change than nondepressed. Linear regression showed significant effect of depression on progression of UMSARS-II scores. Depression correlated with orthostatic and urinary function symptoms on the COMPASS scale. Conclusion: Depression is common in MSA and is associated with faster disease progression and higher burden of autonomic symptoms. Recognizing and treating depression may improve quality of life and ameliorate symptoms

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive deposition of amyloid-beta (Abeta) and dysregulation of neurotrophic signaling, causing synaptic dysfunction, loss of memory, and cell death. The expression of p75 neurotrophin receptor is elevated in the brain of AD patients, suggesting its involvement in this disease. However, the exact mechanism of its action is not yet clear. Here, we show that p75 interacts with beta-site amyloid precursor protein cleaving enzyme-1 (BACE1), and this interaction is enhanced in the presence of Abeta. Our results suggest that the colocalization of BACE1 and amyloid precursor protein (APP) is increased in the presence of both Abeta and p75 in cortical neurons. In addition, the localization of APP and BACE1 in early endosomes is increased in the presence of Abeta and p75. An increased phosphorylation of APP-Thr668 and BACE1-Ser498 by c-Jun N-terminal kinase (JNK) in the presence of Abeta and p75 could be responsible for this localization. In conclusion, our study proposes a potential involvement in amyloidogenesis for p75, which may represent a future therapeutic target for AD.