A5000522879- Visual perception and processing mechanisms
- Neural and Behavioral Psychology Studies
- Face Recognition and Perception
- Spatial Neglect and Hemispheric Dysfunction
- Neural dynamics and brain function
- Ophthalmology and Visual Impairment Studies
- Neurological Disorders and Treatments
- Multisensory perception and integration
- Body Image and Dysmorphia Studies
- Schizophrenia research and treatment
- Death, Funerary Practices, and Mourning
- Color Science and Applications
- Primate Behavior and Ecology
- Visual Attention and Saliency Detection
- Acute Ischemic Stroke Management
- Olfactory and Sensory Function Studies
- Eating Disorders and Behaviors
- Surface Roughness and Optical Measurements
- Pain Management and Placebo Effect
- Vestibular and auditory disorders
- EEG and Brain-Computer Interfaces
- Cerebrovascular and Carotid Artery Diseases
- Aesthetic Perception and Analysis
- Retinal Imaging and Analysis
- Brain Tumor Detection and Classification
University of Bremen
2007-2020
It is widely agreed that in object categorization bottom-up and top-down influences interact. How processes affect has been primarily investigated isolation, with only one higher level process at a time being manipulated. Here, we investigate the combination of different (by varying category, animacy background object) their effect on rapid categorization. Subjects participated two-alternative forced choice task, while measured accuracy reaction times. had to categorize objects...
In human and nonhuman primates, goal-directed behavior requires the selection of relevant pieces information from multitude simultaneous sensory inputs. Feature-based attention (FBA) plays a crucial role in this by improving neuronal representation an attended stimulus feature. Of particular interest for understanding mechanisms behind FBA is processing fate spatially unattended stimuli, either sharing feature attribute or belonging to nonattended dimension. Using wide range cue/stimulus...
Background Temporal visual processing is strongly deteriorated in patients with schizophrenia. For example, the interval required between a stimulus and subsequent mask has to be much longer schizophrenic than healthy controls. We investigated whether this deficit temporal resolution accompanied by prolonged persistence and/or deficient precision (temporal asynchrony perception). Methodology/Principal Findings three experiments. In first, measuring so-called backward masking, visible...
After a stroke involving the left occipitotemporal cortex our patient shows word-length effect and has problems to identify letters or numbers in strings of symbols. But he is normal identifying isolated non-verbally categorizing even complex images such as faces natural scenes. His cortical lesion stretching from visual word form area (VWFA) anteriorly causing additional name stimuli match acoustic with images. We conclude that suffers pure alexia without deficits stimuli. Our results...
We present the results of 51 stroke patients with free central visual fields which about half suffer from clear deficits midlevel vision undetected by standard clinical tests. These yield significantly elevated thresholds for detection and/or discrimination between forms defined motion, colour, or line orientation ('texture'). As demonstrated voxel-based lesion-symptom mapping (VLSM) underlying lesions involve mainly area human V4 (hV4) located in posterior third fusiform gyrus and extending...
4 Since scenes in nature are highly dynamic, perception requires an on-going and robust 5 integration of local information into global representations. In vision, contour (CI) 6 is one these tasks, it performed by our brain a seemingly effortless manner. 7 Following the rule good continuation, oriented line segments linked percepts, 8 thus supporting important visual computations such as detection object boundaries. 9 This process has been studied almost exclusively using static stimuli,...
Contour integration (CI) is an integral part of visual information processing requiring the combination aligned edge configurations into coherent percepts. Subjects are efficient at detecting contours, reaching peak performances for stimulus presentation times 100-200ms. CI research usually employs flashed static stimuli, making this artificial situation compared to continuous observation everyday scenes. We addressed discrepancy between commonly employed stimuli in and natural vision by...
Patients were recruited between 2007 and 2011 at the Charite (Berlin) Stroke Unit (Medical Hospital Bremen). Inclusion criteria: ischemic cerebral infarction affecting occipital lobes adjacent temporal or parietal areas. Exclusion severe aphasia, ophthalmological disorders (e.g. glaucoma cataract), any other neurological psychiatric disorder epilepsy schizophrenia). Neurological neuropsychological characteristics of stroke Cathleen Grimsen, Antje Kraft, Maren Prass, Markus Bahnemann,...
During normal aging both the optics and retina of eye changes, primarily deteriorating visual acuity. Relatively little is known about other abilities effects on primary pathway. Improving knowledge perceptual in elderly essential for understanding impaired functions after brain damage (such as stroke), particularly because required differentiation between age-based damage-specific decline. Here we examined influence age performance detection discrimination using various submodalities...
A permanent change of perception as a result experience is defined perceptual learning. It known that the improvement very specific, e.g. for precise stimulus orientation and position, indicating underlying plastic changes are at least partly on level primary visual cortex (Fahle, J Vis. 2004). Here we examined role task (binocular detection vs. discrimination) in different modalities (contrast, texture, motion, stereo, colour; see also Grimsen et al., this conference), using same position...
Visual backward masking is a very sensitive tool for studying early visual processing deficits and reliable endophenotype of schizophrenia. Mental diseases strongly overlap in many aspects, example, psychopathology, cognition, genetics. Here, we show that strong are found patients with functional psychoses but not non-psychotic patients, namely, depressive abstinent alcoholics. We tested 28 schizophrenic, 22 schizoaffective, 20 bipolar 26 major 23 alcoholics, 24 healthy control subjects...