Visual pathways
Dotaz
Zobrazit nápovědu
Inconsistent information from different modalities can be delusive for perception. This phenomenon can be observed with simultaneously presented inconsistent numbers of brief flashes and short tones. The conflict of bimodal information is reflected in double flash or fission, and flash fusion illusions, respectively. The temporal resolution of the vision system plays a fundamental role in the development of these illusions. As the parallel, dorsal and ventral pathways have different temporal resolution we presume that these pathways play different roles in the illusions. We used pathway-optimized stimuli to induce the illusions on separately driven visual streams. Our results show that both pathways support the double flash illusion, while the presence of the fusion illusion depends on the activated pathway. The dorsal pathway, which has better temporal resolution, does not support fusion, while the ventral pathway which has worse temporal resolution shows fusion strongly.
- MeSH
- akustická stimulace MeSH
- časové faktory MeSH
- iluze * MeSH
- lidé MeSH
- mladý dospělý MeSH
- psychometrie MeSH
- sluchová percepce MeSH
- světelná stimulace metody MeSH
- teorie detekce signálu MeSH
- zraková percepce * MeSH
- zrakové dráhy fyziologie MeSH
- zrakové korové centrum fyziologie MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Audio-visual integration has been shown to be present in a wide range of different conditions, some of which are processed through the dorsal, and others through the ventral visual pathway. Whereas neuroimaging studies have revealed integration-related activity in the brain, there has been no imaging study of the possible role of segregated visual streams in audio-visual integration. We set out to determine how the different visual pathways participate in this communication. We investigated how audio-visual integration can be supported through the dorsal and ventral visual pathways during the double flash illusion. Low-contrast and chromatic isoluminant stimuli were used to drive preferably the dorsal and ventral pathways, respectively. In order to identify the anatomical substrates of the audio-visual interaction in the two conditions, the psychophysical results were correlated with the white matter integrity as measured by diffusion tensor imaging.The psychophysiological data revealed a robust double flash illusion in both conditions. A correlation between the psychophysical results and local fractional anisotropy was found in the occipito-parietal white matter in the low-contrast condition, while a similar correlation was found in the infero-temporal white matter in the chromatic isoluminant condition. Our results indicate that both of the parallel visual pathways may play a role in the audio-visual interaction.
- MeSH
- akustická stimulace MeSH
- anizotropie MeSH
- bílá hmota fyziologie MeSH
- dospělí MeSH
- lidé MeSH
- mapování mozku MeSH
- sluchová percepce fyziologie MeSH
- světelná stimulace MeSH
- teorie detekce signálu fyziologie MeSH
- zobrazování difuzních tenzorů MeSH
- zobrazování trojrozměrné MeSH
- zraková percepce fyziologie MeSH
- zrakové dráhy fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
1st ed. 277 s.
This article is dedicated to main information about visual field, monocular and binocular ranges of visual field including their defects. Visual field loss may occur to disease of the eye, optic nerve or brain. Typical changes are present at glaucoma and macular degeneration. Visual pathway is also mentioned. The basic medical examinations of visual fields are Amsler grid, kinetic and static perimetry and the other. Newer method is microperimetry which detects the changes directly on the retina. The aim of this poster is importance and determination of visual field as a preventive ophthalmologic and optometric examination.
- MeSH
- lidé MeSH
- testy zrakového pole MeSH
- zraková pole * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- hodnotící studie jako téma MeSH
- lidé MeSH
- testy zrakového pole metody využití MeSH
- zraková pole genetika MeSH
- zrakové dráhy patologie MeSH
- zrakové evokované potenciály fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- recenze MeSH
The purpose of this study is to provide an overview of the replacements used in lost vision in the form of the bionic eye, to show their deficiencies and outline other possibilities for non-invasive stimulation of functional areas of the visual cortex. The review highlights the damage not only to the primary altered cellular structures, but also to all other horizontally and vertically localised structures. Based on the results of a large number of functional magnetic resonance imaging and electrophysiological methods, the authors focus on the pathology of the entire visual pathway in pigmentary retinopathy (PR) and age-related macular degeneration (AMD). This study provides a recent overview of the possible systems used to replace lost vision. These range from stimulation with intraocular implants, through stimulation of the optic nerve and lateral geniculate nucleus to the visual cortex. The second part deals with the design of image processing technology and its transformation into the form of transcranial stimulation of undamaged parts of the brain, which is protected by a patent. This is comprehensive overview of the current possibilities of replacement of lost vision and a proposal for a new non-invasive methods of stimulation of functional neurons of the visual cortex.
- MeSH
- elektrostimulační terapie * metody MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- mozek MeSH
- nervus opticus patologie MeSH
- zrakové korové centrum * patologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The processing of visual motion was tested by means of event related potentials recording (ERP) using a paradigm designed to produce a visual mismatch negativity effect. The stimuli were unattended and presented in the peripheral visual field (outside the central 15 degrees). The standard stimulus consisted of an up/down motion sequence, whilst the deviant stimulus of a down/up motion sequence. Significant ERP differences between the standard and deviant conditions were found in 8 out of 10 adult subjects already in 80 ms and prevailingly in interval 145-260 ms from the initial stimulus presentation. The results demonstrate that the magnocellular information undergoes processing capable of detecting differences in the sequence of unattended peripheral motion stimuli.
- MeSH
- dospělí MeSH
- elektroencefalografie MeSH
- evokované potenciály MeSH
- financování organizované MeSH
- lidé středního věku MeSH
- lidé MeSH
- pozornost fyziologie MeSH
- světelná stimulace metody MeSH
- vnímání pohybu fyziologie MeSH
- zraková pole genetika MeSH
- zrakové dráhy fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
OBJECTIVE: Methamphetamine (MAP) is an indirect dopamine agonist that can temporarily increase cognitive performance. However, its long-term abuse may cause dopamine depletion and consequent cognitive and attentional impairment. The worsening of visual functions in Parkinson's disease and their improvement after levodopa administration implicates the role of dopamine in the physiology of vision. This provides the rationale for the investigation of visual functions in abstaining MAP abusers. METHODS: We investigated changes in visually evoked potentials (VEPs) to pattern-reversal and motion-onset stimuli. Such changes serve as indices of visual information processing in the primary and associative areas in a group of recently abstaining MAP abusers (5 females, 18 males, MAP abuse 5.3 +/- 2.8 years) and in 23 age- and gender-paired controls. RESULTS: We did not find differences between the groups in visual acuity. In the group of MAP abusers we observed an attenuation of the early responses around 80 ms and a prolongation of the P1 peak latency after the reversal of high spatial frequency checkerboards (10 and 20 arcmin checks). Furthermore, an attenuation of the latter positive response (170-250 ms) was observed among all the stimuli in parieto-frontal derivations for the MAP abusers. CONCLUSIONS: This is the first report suggesting a slowing and attenuation of VEP responses during visual processing in abstaining methamphetamine abusers.
- MeSH
- dospělí MeSH
- lidé MeSH
- methamfetamin škodlivé účinky MeSH
- mladý dospělý MeSH
- poruchy spojené s užíváním amfetaminu patofyziologie MeSH
- vnímání pohybu fyziologie MeSH
- zrakové dráhy patofyziologie MeSH
- zrakové evokované potenciály fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
