Historical and Cross-Cultural Perspectives on Parkinson\u27s Disease

Parkinson’s disease (PD) is a common neurodegenerative disorder, affecting up to 10 million people worldwide according to the Parkinson’s Disease Foundation. Epidemiological and genetic studies show a preponderance of idiopathic cases and a subset linked to genetic polymorphisms of a familial nature. Traditional Chinese medicine and Ayurveda recognized and treated the illness that Western Medicine terms PD millennia ago, and descriptions of Parkinson’s symptomatology by Europeans date back 2000 years to the ancient Greek physician Galen. However, the Western nosological classification now referred to in English as “Parkinson’s disease” and the description of symptoms that define it, are accredited to British physician James Parkinson, who in 1817 authored The Shaking Palsy. Later in the nineteenth century, French neurologist Jean-Martin Charcot re-labeled paralysis agitans “Parkinson’s disease” and over a century of scientific research ensued. This review discusses European, North American, and Asian contributions to the understanding and treatment of PD from ancient times through the twentieth century

Does emotional memory enhancement assist the memory-impaired?

We review recent work on emotional memory enhancement in older adults and patients with mild cognitive impairment (MCI) or Alzheimer dementia (AD) and evaluate the viability of incorporating emotional components into cognitive rehabilitation for these groups. First, we identify converging evidence regarding the effects of emotional valence on working memory in healthy aging. Second, we introduce work that suggests a more complex role for emotional memory enhancement in aging and identify a model capable of unifying disparate research findings. Third, we survey the neuroimaging literature for evidence of a special role for the amygdala in MCI and early AD in emotional memory enhancement. Finally, we assess the theoretical feasibility of incorporating emotional content into cognitive rehabilitation given all available evidence

Optical splitter/combiner with an adiabatic mixing region

An optical splitter/combiner having an adiabatic mixing region for optically interconnecting a plurality of optical fibers. The change in shape of the adiabatic mixing region is purposely gradual so as to introduce little optical loss. The shape of the adiabatic mixing region is varied so as to minimize the change in the cross-sectional area of the adiabatic mixing region. The optical splitter/combiner is fabricated by the utilizing two subassemblies which when fitted together form the adiabatic mixing region. This formed mixing region is adapted to accepting a linear array of optical fibers in one end and a single optical fiber in the other end. The core area of the optical fibers in one end is not necessarily equivalent to those of the other end but instead are sized to ensure the relatively efficient transfer of optical energy. The adiabatic mixing region is filled with resin, and the numerical apertures of the optical fibers and the resin-filled mixing region are substantially matched. The subassemblies form an optical cladding for the adiabatic mixing region.Published versio

Excess current in point contacts on two-band superconductor MgB2_2 in magnetic field

Series of $I(V)$ characteristic and bias-dependent differential resistance $dV/dI(V)$ for point-contacts on the single crystals of two-band superconductor MgB$_2$ were measured in magnetic field up to 9 T. We have obtained magnetic field dependences of the excess current on the $I(V)$ curves and analyzed them using Koshelev and Golubov (Phys. Rev. Lett. {\bf 90}, 177002 (2003)) theoretical results for the mixed state of a dirty two-band superconductor. Introducing a simple model for the excess current in the point contact in the mixed state our data can be qualitatively described utilizing theoretical magnetic filed behavior of the $\sigma$ and $\pi$-band superconducting order parameters and the corresponding averaged electronic density of states in MgB$_2$.Comment: 4 pages, 3 figs, RevTex4; V2: plain text improved, BTK fit is added to insets of Fig.

Dopaminergic Modulation of Medial Prefrontal Cortex Deactivation in Parkinson Depression

Parkinson\u27s disease (PD) is associated with emotional abnormalities. Dopaminergic medications ameliorate Parkinsonian motor symptoms, but less is known regarding the impact of dopaminergic agents on affective processing, particularly in depressed PD (dPD) patients. The aim of this study was to examine the effects of dopaminergic pharmacotherapy on brain activation to emotional stimuli in depressed versus nondepressed Parkinson disease (ndPD) patients. Participants included 18 ndPD patients (11 men, 7 women) and 10 dPD patients (7 men, 3 women). Patients viewed photographs of emotional faces during functional MRI. Scans were performed while the patient was taking anti-Parkinson medication and the day after medication had been temporarily discontinued. Results indicate that dopaminergic medications have opposite effects in the prefrontal cortex depending upon depression status. DPD patients show greater deactivation in the ventromedial prefrontal cortex (VMPFC) on dopaminergic medications than off, while ndPD patients show greater deactivation in this region off drugs. The VMPFC is in the default-mode network (DMN). DMN activity is negatively correlated with activity in brain systems used for external visual attention. Thus dopaminergic medications may promote increased attention to external visual stimuli among dPD patients but impede normal suppression of DMN activity during external stimulation among ndPD patients

Dopaminergic Modulation of Memory and Affective Processing in Parkinson Depression

Depression is common in Parkinson\u27s disease and is associated with cognitive impairment. Dopaminergic medications are effective in treating the motor symptoms of Parkinson\u27s disease; however, little is known regarding the effects of dopaminergic pharmacotherapy on cognitive function in depressed Parkinson patients. This study examines the neuropsychological effects of dopaminergic pharmacotherapy in Parkinsonian depression. We compared cognitive function in depressed and non-depressed Parkinson patients at two time-points: following overnight withdrawal and after the usual morning regimen of dopaminergic medications. A total of 28 non-demented, right-handed patients with mild to moderate idiopathic Parkinson\u27s disease participated. Ten of these patients were depressed according to DSM IV criteria. Results revealed a statistically significant interaction between depression and medication status on three measures of verbal memory and a facial affect naming task. In all cases, depressed Parkinson\u27s patients performed significantly more poorly while on dopaminergic medication than while off. The opposite pattern emerged for the non-depressed Parkinson\u27s group. The administration of dopaminergic medication to depressed Parkinson patients may carry unintended risks

Andreev Reflection and Spin Injection into s−s- and d−d-wave Superconductors

We study the effect of spin injection into $s-$ and $d-$wave superconductors, with an emphasis on the interplay between boundary and bulk spin transport properties. The quantities of interest include the amount of non-equilibrium magnetization ($m$), as well as the induced spin-dependent current ($I_s$) and boundary voltage ($V_s$). In general, the Andreev reflection makes each of the three quantities depend on a different combination of the boundary and bulk contributions. The situation simplifies either for half-metallic ferromagnets or in the strong barrier limit, where both $V_s$ and $m$ depend solely on the bulk spin transport/relaxation properties. The implications of our results for the on-going spin injection experiments in high $T_c$ cuprates are discussed.Comment: 4 pages, REVTEX, 1 figure included; typos correcte

Andreev reflections in the pseudogap state of cuprate supercondcutors

We propose that, if the pseudogap state in the cuprate superconductors can be described in terms of the phase-incoherent preformed pairs, there should exist Andreev reflection from these pairs even above the superconducting transition temperature, $T_c$. After giving qualitative arguments for this effect, we present more quantitative calculations based on the Bogoliubov--de Gennes equation. Experimental observations of the effects of Andreev reflections above $T_c$---such as an enhanced tunneling conductance below the gap along the copper oxide plane---could provide unambiguous evidence for the preformed pairs in the pseudogap state.Comment: 5 pages, 1 figur

Josephson effect in a few-hole quantum dot

We use a Ge-Si core-shell nanowire to realise a Josephson field-effect transistor with highly transparent contacts to superconducting leads. By changing the electric field we gain access to two distinct regimes not combined before in a single device: In the accumulation mode the device is highly transparent and the supercurrent is carried by multiple subbands, while near depletion supercurrent is carried by single-particle levels of a strongly coupled quantum dot operating in the few-hole regime. These results establish Ge-Si nanowires as an important platform for hybrid superconductor-semiconductor physics and Majorana fermions

Measurement Properties of the Functional Outcomes Questionnaire for Aphasia

Aphasia often results in negative social, emotional, and financial consequences endorsing rehabilitation efforts that influence communication beyond the level of impairment. The FOQ-A assesses the impact of aphasia treatment on functional communication, extending measurement into activity and participation. The purpose of this study is to evaluate the measurement properties of the FOQ-A in a sample of 127 individuals with moderate to severe aphasia subsequent to stroke. Results of Rasch analysis indicate that the FOQ-A is unidimensional, has good internal consistency, and contains adequate person separation for measuring change after rehabilitation; however, revisions to the scale may improve its usefulness