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OBJECTIVE: To identify intracerebral sites activated after correct motor response during cognitive task and to assess associations of this activity with mental processes. METHODS: Intracerebral EEG was recorded from 205 sites of frontal, temporal and parietal lobes in 18 epileptic patients, who responded by button pressing together with mental counting to target stimuli in visual oddball task. RESULTS: Post-movement event-related potentials (ERPs) with mean latency 295 ± 184 ms after movement were found in all subjects in 64% of sites investigated. Generators were consistently observed in mesiotemporal structures, anterior midcingulate, prefrontal, and temporal cortices. Task-variant nonspecific and target specific post-movement ERPs were identified, displaying no significant differences in distribution among generating structures. Both after correct and incorrect performances the post-performance ERPs were observed in frontal and temporal cortices with latency sensitive to error commission in several frontal regions. CONCLUSION: Mesiotemporal structures and regions in anterior midcingulate, prefrontal and temporal cortices seem to represent integral parts of network activated after correct motor response in visual oddball task with mental counting. Our results imply equivalent involvement of these structures in task-variant nonspecific and target specific processes, and suggest existence of common nodes for correct and incorrect responses. SIGNIFICANCE: Our results contribute to better understanding of neural mechanisms underlying goal-directed behavior.
- MeSH
- dospělí MeSH
- elektroencefalografie metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mozek fyziologie MeSH
- pohyb fyziologie MeSH
- psychomotorický výkon fyziologie MeSH
- světelná stimulace metody MeSH
- zrakové evokované potenciály fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Traditionally, the pathophysiology of cervical dystonia has been regarded mainly in relation to neurochemical abnormities in the basal ganglia. Recently, however, substantial evidence has emerged for cerebellar involvement. While the absence of neurological "cerebellar signs" in most dystonia patients may be considered at least provoking, there are more subtle indications of cerebellar dysfunction in complex, demanding tasks. Specifically, given the role of the cerebellum in the neural representation of time, in the millisecond range, dysfunction to this structure is considered to be of greater importance than dysfunction of the basal ganglia. In the current study, we investigated the performance of cervical dystonia patients on a computer task known to engage the cerebellum, namely, the interception of a moving target with changing parameters (speed, acceleration, and angle) with a simple response (pushing a button). The cervical dystonia patients achieved significantly worse results than a sample of healthy controls. Our results suggest that the cervical dystonia patients are impaired at integrating incoming visual information with motor responses during the prediction of upcoming actions, an impairment we interpret as evidence of cerebellar dysfunction.
- MeSH
- bazální ganglia patofyziologie MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- motorické korové centrum patofyziologie MeSH
- mozeček patofyziologie MeSH
- pohyb fyziologie MeSH
- psychomotorický výkon fyziologie MeSH
- reakční čas fyziologie MeSH
- senioři MeSH
- tortikolis vrozené patofyziologie MeSH
- vnímání času fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: Supplementary motor area (SMA) was suggested to have a dominant role in the temporal control of behavior by many neuroimaging studies. The aim of this study was to support this hypothesis by influencing time estimates with theta burst transcranial magnetic stimulation (TMS) over the SMA. METHODS: Nineteen healthy volunteers with a mean age 25.9±3 (SD) years performed the time reproduction task (TRT) before and after 190 seconds of intermittent theta-burst TMS over SMA and the precuneus (total 600 pulses). The TRT consisted of an encoding phase (during which visual stimuli with durations of 5, 10 and 16.82 seconds were presented pseudorandomly) and a reproduction phase (during which interval durations were reproduced by pressing a button). Mean subjects' interval estimates as a measure of accuracy and standard deviation as a measure of variability pre-TMS and post-TMS were compared. RESULTS: Theta-burst TMS over both areas had no effect on the accuracy of duration estimates. An increased variability of interval reproduction was present after stimulation of the precuneus (p<0.01) with the biggest effect on the five second interval. Stimulation of SMA caused a decrease of variability in the ten second interval only (p<0.05). CONCLUSION: It is likely that increased variability of time estimates is a non-specific result of impaired attention and working memory after theta-burst TMS. Decreased variability after stimulation over the SMA could be explained in terms of enhanced activity of the physiological oscillator with a frequency close to 0.1 Hz.
- MeSH
- dospělí MeSH
- kognice fyziologie MeSH
- krátkodobá paměť fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- motorické korové centrum fyziologie MeSH
- pozornost fyziologie MeSH
- psychomotorický výkon fyziologie MeSH
- světelná stimulace metody MeSH
- theta rytmus EEG fyziologie MeSH
- transkraniální magnetická stimulace metody MeSH
- vnímání času fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The aim of our study was to verify reported visual dysfunctions of patients with Alzheimer disease with the use of several variants of VEPs and visual ERPs and to learn whether these methods can be useful in diagnostics of AD. We tested 15 patients (6 women and 9 men, aged from 58 to 87) with mild to moderate Alzheimer disease (12-23 points of Mini Mental State Examination) and 15 age, gender and education level matched controls. The examination consisted of VEPs to pattern-reversal and motion-onset stimulation (to translational and radial movement) and of visual ERPs recorded during an odd-ball test. The subjects were instructed to signalize target stimuli by pressing of a button, which enabled to evaluate also the reaction time. While pattern-reversal VEPs were comparable in patients and controls, there were significantly smaller N2 peak amplitudes of motion-onset VEPs in patients with AD (in particular in radial moving stimuli outside the central 20 deg of the visual field), which suggests a dysfunction of the motion-processing (magnocellular) system or the dorsal cortical stream. ERPs, having significantly longer latencies in patients than in controls, distinguished well both groups. However, the individual AD diagnostics based on ERPs seems to be limited by rather high inter-individual variability of the ERP latencies. The ERPs might, however, be useful in disease progress and therapy effect estimation. Electrophysiological parameters did not correlate with neuropsychological ADAS cog test (Alzheimer Disease Assessment Scale--cognitive part).
- MeSH
- Alzheimerova nemoc patofyziologie psychologie MeSH
- evokované potenciály MeSH
- kognice MeSH
- lidé středního věku MeSH
- lidé MeSH
- psychologické testy MeSH
- reakční čas MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- stupeň závažnosti nemoci MeSH
- světelná stimulace metody MeSH
- vnímání pohybu MeSH
- zrakové evokované potenciály MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
V práci je popísaný nový irigačný iris retraktor pre operácie kataraty v úzkej zrenici. Je modifikáciou irigačného násadca z bimanuálnej irigácie aspirácie, ktorý má na svojom konci umiestnený háčik gombíkovitého tvaru. Tento umožňuje odhrnutie okraja úzkej zrenice a vizualizáciu zbytkov kortexu v ekvatoriálnej oblasti kapsuly. Puzdro šošovky tak môže byť bezpečne vyčistené pri použití aspiračnej kanyly v chirurgovej druhej ruke.
I describe a new irrigating iris retractor for cataract surgery in small pupils. The retractor, a modified irrigating handpiece has a smooth button-like iris hook in the front. The hook is inserted into the margin of a small pupil and retract the pupil peripherally to allow visualisation of cortical remnant in the equatorial area of the lens capsule. The capsule can then be safely cleaned using the aspirating handpiece in the surgeon’s other hand.
