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Biomedical subjects

P S Hyde

Publications and source records attributed to P S Hyde.

7 recordsLinked to original sources
PubMed2001

A topographic instructive signal guides the adjustment of the auditory space map in the optic tectum.

Maps of auditory space in the midbrain of the barn owl (Tyto alba) are calibrated by visual experience. When owls are raised wearing prismatic spectacles that displace the visual field in azimuth, the auditory receptive fields of neurons in the optic tectum shift to compensate for the optical displacement of the visual field. This shift results primarily from a shift in the tuning of tectal neurons for interaural time difference. The visually based instructive signal that guides this plasticity could be based on a topographic, point-by-point comparison between auditory and visual space maps or on a foveation-dependent visual assessment of the accuracy of auditory orienting responses. To distinguish between these two possibilities, we subjected owls to optical conditions that differed in the center of gaze and the visual periphery. A topographic signal would cause the portions of the space map representing the central and peripheral regions of visual space to adjust differently, according to the optical conditions that exist in each region. In contrast, a foveation-based signal would cause both portions of the map to adjust similarly, according to the optical conditions that exist at the center of gaze. In six of seven experiments, adaptive changes were as predicted by a topographic instructive signal. Although the results do not rule out the possible contribution of a foveation-based signal, they demonstrate that a topographic instructive signal is, indeed, involved in the calibration of the auditory space map in the barn owl optic tectum.

Adaptation, Physiological↗
PubMed2001

Policy implications for implementing evidence-based practices.

The authors describe the policy and administrative-practice implications of implementing evidence-based services, particularly in public-sector settings. They review the observations of the contributors to the evidence-based practices series published throughout 2001 in Psychiatric Services. Quality and accountability have become the watchwords of health and mental health services; evidence-based practices are a means to both ends. If the objective of accountable, high-quality services is to be achieved by implementing evidence-based practices, the right incentives must be put in place, and systemic barriers must be overcome. The authors use the framework from the U.S. Surgeon General's 1999 report on mental health to describe eight courses of action for addressing the gap between science and practice: continue to build the science base; overcome stigma; improve public awareness of effective treatments; ensure the supply of mental health services and providers; ensure delivery of state-of-the-art treatments; tailor treatment to age, sex, race, and culture; facilitate entry into treatment; and reduce financial barriers to treatment.

Ethnicity↗
PubMed2001

Mandated community treatment: beyond outpatient commitment.

Outpatient commitment, although often viewed as merely an extension of inpatient commitment, is only one of a growing array of legal tools used to mandate treatment adherence. The authors describe various forms of mandated community treatment. People with severe and chronic mental disorders often depend on goods and services provided by the social welfare system. Benefits disbursed by representative payees and the provision of subsidized housing have both been used as leverage to ensure treatment adherence. Many discharged patients are arrested for criminal offenses. Favorable disposition of their cases by a mental health court may be tied to participation in treatment. Under outpatient commitment statutes, judges can order committed patients to comply with prescribed treatment. Patients may attempt to maximize their control over treatment in the event of later deterioration by executing an advance directive. The ideological posturing that currently characterizes the field must be replaced by an evidence-based approach.

Advance Directives↗
PubMed2000

Topographic projection from the optic tectum to the auditory space map in the inferior colliculus of the barn owl.

In the barn owl (Tyto alba), the external nucleus of the inferior colliculus (ICX) contains a map of auditory space that is calibrated by visual experience. The source of the visually based instructive signal to the ICX is unknown. Injections of biotinylated dextran amine and Fluoro-Gold in the ICX retrogradely labelled neurons in layers 8-15 of the ipsilateral optic tectum (OT) that could carry this instructive signal. This projection was point-to-point and in register with the feed-forward, auditory projection from the ICX to the OT. Most labelled neurons were in layers 10-11, and most were bipolar. Tripolar, multipolar, and unipolar neurons were also observed. Multipolar neurons had dendrites that were oriented parallel to the tectal laminae. In contrast, most labelled bipolar and tripolar neurons had dendrites oriented perpendicular to the tectal laminae, extending superficially into the retino-recipient laminae and deep into the auditory recipient laminae. Therefore, these neurons were positioned to receive both visual and auditory information from particular locations in space. Biocytin injected into the superficial layers of the OT labelled bouton-laden axons in the ICX. These axons were generally finer than, but had similar bouton densities as, feed-forward auditory fibers in the ICX, labelled by injections of biocytin into the central nucleus of the inferior colliculus (ICC). These data demonstrate a point-to-point projection from the OT to the ICX that could provide a spatial template for calibrating the auditory space map in the ICX.

Animals↗
PubMed1996

Mammalian homologues of yeast vacuolar protein sorting (vps) genes implicated in Golgi-to-lysosome trafficking.

Sec1p, Vps33p, Vps45p and Sly1p constitute a family of proteins implicated in vesicle trafficking at distinct stages of the yeast secretory pathway. Several mammalian homologues of Sec1p have been described, including n-sec1 which has been implicated in the regulation of synaptic vesicle docking at the nerve terminal. We have characterized cDNA clones encoding three additional mammalian homologues belonging to this family: r-vps33a and r-vps33b from rat, which are 30 and 26% identical to yeast Vps33p, respectively, and h-vps45 from human which is 38% identical to yeast Vps45p at the amino acid (aa) level. Phylogenetic analysis of 16 Sec1p-related proteins from several species is consistent with the hypothesis that the evolution of this gene family parallels the specialization of vesicle trafficking to distinct intracellular compartments. By Northern analysis, each of these genes is expressed in all tissues examined (brain, spleen, lung, liver, skeletal muscle, kidney, testis). While n-sec1 binds syntaxin 1a, 2, and 3, r-vps33a, r-vps33b and h-vps45 do not bind any of the known syntaxins. We propose that the three proteins bind as yet unidentified syntaxin homologues involved in vesicle trafficking between the Golgi apparatus, prelysosomal compartment(s), and the lysosome.

Adult↗
PubMed1986

Homelessness and mental health policy: developing an appropriate role for the 1980s.

Previous research has reported prevalence rates of mental health problems among homeless individuals that range from 20% to 90%. Attempting to validly verify prevalence rates is important because of the implications concerning both deinstitutionalization and developing an appropriate mental health policy over the next decade. In the present research, which used as its sample the largest homeless sample assessed to date, prevalence was found to fall at the lower range of previously cited data. Despite the fact that the prevalence of mental health problems among the homeless population was found to be relatively low, it was found that homeless people with mental health problems are, at best, only marginally served by the mental health system. Implications for community mental health policymakers and program designers are discussed.

Chronic Disease↗