Faculty Opinions recommendation of Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals.

2015 ◽  
Author(s):  
Peter König ◽  
Aleksey Lytochkin
Keyword(s):  
Prior Knowledge ◽  
Early Psychosis ◽  
Healthy Individuals

scholarly journals Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals

2015 ◽  
Vol 112 (43) ◽  
pp. 13401-13406 ◽  
Author(s):  
Christoph Teufel ◽  
Naresh Subramaniam ◽  
Veronika Dobler ◽  
Jesus Perez ◽  
Johanna Finnemann ◽  
...  
Keyword(s):  
Information Processing ◽  
Prior Knowledge ◽  
Early Psychosis ◽  
Psychotic Symptoms ◽  
Psychotic Experiences ◽  
Healthy Individuals ◽  
Top Down ◽  
Bottom Up ◽  
Psychosis Proneness ◽  
Sensory Evidence

Many neuropsychiatric illnesses are associated with psychosis, i.e., hallucinations (perceptions in the absence of causative stimuli) and delusions (irrational, often bizarre beliefs). Current models of brain function view perception as a combination of two distinct sources of information: bottom-up sensory input and top-down influences from prior knowledge. This framework may explain hallucinations and delusions. Here, we characterized the balance between visual bottom-up and top-down processing in people with early psychosis (study 1) and in psychosis-prone, healthy individuals (study 2) to elucidate the mechanisms that might contribute to the emergence of psychotic experiences. Through a specialized mental-health service, we identified unmedicated individuals who experience early psychotic symptoms but fall below the threshold for a categorical diagnosis. We observed that, in early psychosis, there was a shift in information processing favoring prior knowledge over incoming sensory evidence. In the complementary study, we capitalized on subtle variations in perception and belief in the general population that exhibit graded similarity with psychotic experiences (schizotypy). We observed that the degree of psychosis proneness in healthy individuals, and, specifically, the presence of subtle perceptual alterations, is also associated with stronger reliance on prior knowledge. Although, in the current experimental studies, this shift conferred a performance benefit, under most natural viewing situations, it may provoke anomalous perceptual experiences. Overall, we show that early psychosis and psychosis proneness both entail a basic shift in visual information processing, favoring prior knowledge over incoming sensory evidence. The studies provide complementary insights to a mechanism by which psychotic symptoms may emerge.

scholarly journals O3.6. DEFICITS IN CONTEXT-DEPENDENT ADAPTIVE CODING IN EARLY PSYCHOSIS AND HEALTHY INDIVIDUALS WITH SCHIZOTYPAL PERSONALITY TRAITS

2018 ◽  
Vol 44 (suppl_1) ◽  
pp. S81-S81 ◽  
Author(s):  
Matthias Kirschner ◽  
Amelie Haugg ◽  
Andrei Manoliu ◽  
Erich Seifritz ◽  
Philippe N Tobler ◽  
...  
Keyword(s):  
Personality Traits ◽  
Early Psychosis ◽  
Healthy Individuals ◽  
Adaptive Coding ◽  
Schizotypal Personality ◽  
Context Dependent

Morphological and elemental analysis of isolated incubated frog retina-choroid

1984 ◽  
Vol 42 ◽  
pp. 298-299
Author(s):  
B. J. Panessa-Warren ◽  
J. B. Warren ◽  
H. W. Kraner
Keyword(s):  
Elemental Analysis ◽  
Pigment Epithelium ◽  
Human Retina ◽  
Healthy Individuals ◽  
Anterior Portion ◽  
Pathological Conditions ◽  
Frog Retina ◽  
Isolated Retina ◽  
Vertebrate Eye ◽  
Retina Pigment Epithelium

Our previous studies have demonstrated that abnormally high amounts of calcium (Ca) and zinc (Zn) can be accumulated in human retina-choroid under pathological conditions and that barium (Ba), which was not detected in the eyes of healthy individuals, is deposited in the retina pigment epithelium (RPE), and to a lesser extent in the sensory retina and iris. In an attempt to understand how these cations can be accumulated in the vertebrate eye, a morphological and microanalytical study of the uptake and loss of specific cations (K, Ca,Ba,Zn) was undertaken with incubated Rana catesbiana isolated retina and RPE preparations. Large frogs (650-800 gms) were dark adapted, guillotined and their eyes enucleated in deep ruby light. The eyes were hemisected behind the ora serrata and the anterior portion of the eye removed. The eyecup was bisected along the plane of the optic disc and the two segments of retina peeled away from the RPE and incubated.

Qualitative and quantitative assessment of nailfold capillaries by capillaroscopy in healthy volunteers

VASA ◽  
2012 ◽  
Vol 41 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Hoerth ◽  
Kundi ◽  
Katzenschlager ◽  
Hirschl
Keyword(s):  
Scoring System ◽  
Morphological Changes ◽  
Connective Tissue Diseases ◽  
Capillary Density ◽  
Diagnostic Value ◽  
Healthy Individuals ◽  
Extreme Position ◽  
Qualitative And Quantitative ◽  
Diffuse Loss ◽  
Density Results

Background: Nailfold capillaroscopy (NVC) is a diagnostic tool particularly useful in the differential diagnosis of rheumatic and connective tissue diseases. Although successfully applied since many years, little is known about prevalence and distribution of NVC changes in healthy individuals. Probands and methods: NVC was performed in 120 individuals (57 men and 63 women; age 18 to 70 years) randomly selected according to predefined age and sex strata. Diseases associated with NVC changes were excluded. The nailfolds of eight fingers were assessed according to standardized procedures. A scoring system was developed based on the distribution of the number of morphologically deviating capillaries, microhaemorrhages, and capillary density. Results: Only 18 individuals (15 %) had no deviation in morphology, haemorrhages, or capillary density on any finger. Overall 67 % had morphological changes, 48 % had microhaemorrhages, and 40 % of volunteers below 40 years of age and 18 % above age 40 had less than 8 capillaries/mm. Among morphological changes tortous (43 %), ramified (47 %), and bushy capillaries (27 %) were the most frequently altered capillary types. A semiquantitative scoring system was developed in such a way that a score above 1 indicates an extreme position (above the 90th percentile) in the distribution of scores among healthy individuals. Conclusions: Altered capillaries occur frequently among healthy individuals and should be interpreted as normal unless a suspicious increase in their frequency is determined by reference to the scoring system. Megacapillaries and diffuse loss of capillaries were not found and seem to be of specific diagnostic value.

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