Primary visual cortex
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Ciba Foundation symposium ; 184
[1st ed.] VIII, 347 s. : obr., tab. ; 23 cm
- MeSH
- neurofyziologie MeSH
- oči - fyziologické jevy MeSH
- zrak fyziologie MeSH
- Publikační typ
- kongresy MeSH
- Konspekt
- Lékařské vědy. Lékařství
- NLK Obory
- fyziologie
- neurovědy
- oftalmologie
Visual cortical circuits show profound plasticity during early life and are later stabilized by molecular "brakes" limiting excessive rewiring beyond a critical period. The mechanisms coordinating the expression of these factors during the transition from development to adulthood remain unknown. We found that miR-29a expression in the visual cortex dramatically increases with age, but it is not experience-dependent. Precocious high levels of miR-29a blocked ocular dominance plasticity and caused an early appearance of perineuronal nets. Conversely, inhibition of miR-29a in adult mice using LNA antagomirs activated ocular dominance plasticity, reduced perineuronal nets, and restored their juvenile chemical composition. Activated adult plasticity had the typical functional and proteomic signature of critical period plasticity. Transcriptomic and proteomic studies indicated that miR-29a manipulation regulates the expression of plasticity brakes in specific cortical circuits. These data indicate that miR-29a is a regulator of the plasticity brakes promoting age-dependent stabilization of visual cortical connections.
Cílem práce bylo hodnocení souvislosti mezi excitabilitou motorického a vizuálního kortexu. Pomocí neuronavigované transkraniální magnetické stimulace (TMS, Magstim Rapid) za použití jednoho pulzu (SP) nebo párových pulzu (PP) cílené na pravou vizuální kuru byl hodnocen práh pro indukci fosfénu u 11 dobrovolníku. Standardní metodika pak byla použita pro hodnocení motorického prahu (MT). Fosfény se podařilo indukovat pomocí techniky SP (medián = 48 %, IQR = 44,5–52,0) i PP (medián = 44 %, IQR=39,5–48,0) TMS. Práh pro fosfény indukované PP byl nižší nežli v případě SP (U = 28,0, p ? 0,05). Byla nalezena pozitivní korelace mezi MT a SP fosfénovým prahem (r = 0,597, p ? 0,05) a MT nekoreloval s PP prahy. Vzdálenost cívky od povrchu mozku pak nebyla ve vztahu k MT, SP ani PP fosfénovým prahům. Naše nálezy potvrzují vztah mezi MT a fosfénovým prahem hodnoceným pomocí jednotlivých pulzu nad okcipitálním kortexem vpravo za horizontálního umístění cívky. Navržená metodika muže být použita v experimentech, které hodnotí kortikální excitabilitu vizuální kůry. SP fosfénový práh představuje potenciální standard pro interindividuální srovnání poi TMS experimentech visuální kůry v klinických populacích.
The aim of the study was to investigate the relationship between excitability of motor and visual cortex. Using neuronavigated singlepulse (SP) and paired-pulse (PP) transcranial magnetic stimulation (TMS, Magstim Rapid) over right visual cortex the phosphene thresholds were measured in 11 subjects. Standard methodology was used to identify the motor threshold (MT). In all subjects the phosphenes were induced by both SP (median = 48%, IQR = 44,5–52,0) and PP (medián = 44 %, IQR=39,5–48,0) TMS. The PP phosphene thresholds were lower than the SP thresholds (U = 28,0, p ? 0,05). We found the positive correlation between MT and SP phosphene threshold (r = 0,597, p ? 0,05) but not for MT and PP. The distance of coil position from the brain surface did not correlate with MT, SP nor PP phosphene threshold. Our findings confirm the relationship between MT a phosphene threshold measured by the use of single-pulse technique over right occipital cortex with horizontal position of coil. The propose methodology should be used in experiments where cortical excitability of visual cortex is measured. SP phosphene threshold is proposed as a potential standard for inter-individual comparison in visual TMS experiments in ppatientspatients.
Cíl: Představit historii a současnost zrakových korových neuroprotéz a předložit novou metodu stimulace nepoškozených buněk zrakové kůry. Metody: Práce podává nejen přehled o historii a současném stavu stimulace zrakové kůry u těžkých poruch zraku, ale hlavně upozorňuje na jejich nedostatky. K nim se řadí hlavně stimulace právě poškozených korových buněk na malé ploše a z morfologického hlediska pak možné poškození stimulovaných neuronů elektrodami a jejich zapouzdření gliotickou tkání. Výsledky: Práce dále předkládá návrh nové technologie zpracování obrazu a jeho transformace do podoby neinvazivní transkraniální stimulace nepoškozených částí mozku, která je chráněna národním i mezinárodním patentem. Závěr: V práci je předložen ucelený přehled současných možností náhrady ztraceného zraku na úrovni mozkové kůry a návrh nové neinvazivní metody stimulace funkčních neuronů zrakové kůry.
Purpose: The purpose of the article is to present the history and current status of visual cortical neuroprostheses, and to present a new method of stimulating intact visual cortex cells. Methods: This paper contains an overview of the history and current status of visual cortex stimulation in severe visual impairment, but also highlights its shortcomings. These include mainly the stimulation of currently damaged cortical cells over a small area and, from a morphological point of view, possible damage to the stimulated neurons by the electrodes and their encapsulation by gliotic tissue. Results: The paper also presents a proposal for a new technology of image processing and its transformation into a form of non-invasive transcranial stimulation of undamaged parts of the brain, which is protected by a national and international patent. Conclusion: The paper presents a comprehensive review of the current options for compensating for lost vision at the level of the cerebral cortex and a proposal for a new non-invasive method of stimulating the functional neurons of the visual cortex.
- Klíčová slova
- zraková neuroprotéza,
- MeSH
- kvalita života MeSH
- lidé MeSH
- nemoci retiny klasifikace terapie MeSH
- oční protézy * klasifikace MeSH
- primární vizuální kortex MeSH
- transkraniální magnetická stimulace * metody přístrojové vybavení MeSH
- zrak MeSH
- zrakově postižení MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
OBJECTIVE: Adaptive interactions with the outer world necessitate effective connections between cognitive and executive functions. The primary motor cortex (M1) with its control of the spinal cord motor apparatus and its involvement in the processing of cognitive information related to motor functions is one of the best suited structures of this cognition-action connection. The question arose whether M1 might be involved also in situations where no overt or covered motor action is present. METHODS: The EEG data analyzed were recorded during an oddball task in one epileptic patient (19 years) with depth multilead electrodes implanted for diagnostic reasons into the M1 and several prefrontal areas. RESULTS: The main result was the finding of an evoked response to non-target stimuli with a pronounced late component in all frontal areas explored, including three loci of the M1. The late component was implicated in the evaluation of predicted and actual action and was synchronized in all three precentral loci and in the majority of prefrontal loci. CONCLUSION: The finding is considered as direct evidence of functional involvement of the M1 in cognitive activity not related to motor function. SIGNIFICANCE: Our results contribute to better understanding of neural mechanisms underlying cognition.
- MeSH
- elektroencefalografie metody MeSH
- kognice fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- motorické korové centrum fyziologie MeSH
- světelná stimulace metody MeSH
- zrakové evokované potenciály fyziologie MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
An electrophysiological study on the effect of aging on the visual pathway and various levels of visual information processing (primary cortex, associate visual motion processing cortex and cognitive cortical areas) was performed. We examined visual evoked potentials (VEPs) to pattern-reversal, motion-onset (translation and radial motion) and visual stimuli with a cognitive task (cognitive VEPs - P300 wave) at luminance of 17 cd/m(2). The most significant age-related change in a group of 150 healthy volunteers (15-85 years of age) was the increase in the P300 wave latency (2 ms per 1 year of age). Delays of the motion-onset VEPs (0.47 ms/year in translation and 0.46 ms/year in radial motion) and the pattern-reversal VEPs (0.26 ms/year) and the reductions of their amplitudes with increasing subject age (primarily in P300) were also found to be significant. The amplitude of the motion-onset VEPs to radial motion remained the most constant parameter with increasing age. Age-related changes were stronger in males. Our results indicate that cognitive VEPs, despite larger variability of their parameters, could be a useful criterion for an objective evaluation of the aging processes within the CNS. Possible differences in aging between the motion-processing system and the form-processing system within the visual pathway might be indicated by the more pronounced delay in the motion-onset VEPs and by their preserved size for radial motion (a biologically significant variant of motion) compared to the changes in pattern-reversal VEPs.
- MeSH
- dospělí MeSH
- kognice fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- reakční čas fyziologie MeSH
- rozpoznávání obrazu fyziologie MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- stárnutí fyziologie MeSH
- světelná stimulace metody MeSH
- vnímání pohybu fyziologie MeSH
- zrakové dráhy fyziologie MeSH
- zrakové evokované potenciály fyziologie MeSH
- zrakové korové centrum fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
INTRODUCTION: Neural activity can be described in terms of probability distributions that are continuously evolving in time. Characterizing how these distributions are reshaped as they pass between cortical regions is key to understanding how information is organized in the brain. METHODS: We developed a mathematical framework that represents these transformations as information-theoretic gradient flows - dynamical trajectories that follow the steepest ascent of entropy and expectation. The relative strengths of these two functionals provide interpretable measures of how neural probability distributions change as they propagate within neural systems. Following construct validation in silico, we applied the framework to publicly available continuous ΔF/F two-photon calcium recordings from the mouse visual cortex. RESULTS: The analysis revealed consistent bi-directional transformations between the rostrolateral area and the primary visual cortex across all five mice. These findings demonstrate that the relative contributions of entropy and expectation can be disambiguated and used to describe information flow within cortical networks. DISCUSSION: We introduce a framework for decomposing neural signal transformations into interpretable information-theoretic components. Beyond the mouse visual cortex, the method can be applied to diverse neuroimaging modalities and scales, thereby providing a generalizable approach for quantifying how information geometry shapes cortical communication.
- Publikační typ
- časopisecké články 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
We performed a systematic study to check whether neurons in the area TE (the anterior part of inferotemporal cortex) in rhesus monkey, regarded as the last stage of the ventral visual pathway, could be modulated by auditory stimuli. Two fixating rhesus monkeys were presented with visual, auditory or combined audiovisual stimuli while neuronal responses were recorded. We have found that the visually sensitive neurons are also modulated by audiovisual stimuli. This modulation is manifested as the change of response rate. Our results have shown also that the visual neurons were responsive to the sole auditory stimuli. Therefore, the concept of inferotemporal cortex unimodality in information processing should be re-evaluated.
- MeSH
- akustická stimulace metody využití MeSH
- experimenty na zvířatech MeSH
- financování organizované MeSH
- Haplorrhini MeSH
- implantované elektrody využití MeSH
- Macaca mulatta MeSH
- metaanalýza jako téma MeSH
- mozková kůra anatomie a histologie fyziologie MeSH
- neurony fyziologie MeSH
- sluchové evokované potenciály fyziologie MeSH
- sluchové korové centrum anatomie a histologie fyziologie MeSH
- statistika jako téma MeSH
- světelná stimulace metody MeSH
