Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 93 (1993), S. 345-351 
    ISSN: 1432-1106
    Keywords: Visual motion perception ; Cortical motion ; area ; Dipole source analysis ; Evoked potentials ; Akinetopsia ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The retinal periphery of nine healthy subjects was stimulated with computer-generated random-dot kinematograms. These stimuli provided almost isolated visual motion information and minimal position cues. Pattern-reversal stimuli at the same location in the visual field were used for control. Stimulus-related electrical brain activity was recorded from 29 scalp electrodes. Total mean and individual data were analyzed with a spatiotemporal multiple dipole model. The scalp potentials showed a different spatial distribution for motion and pattern stimulation in the time range of 160–200 ms. In this epoch, the predominant motion-related source activity was localized in the region of the contralateral occipital-temporal-parietal border. A significant ipsilateral source activity was not found. The predominant source activity related to the pattern stimulus occurred in the same epoch. The corresponding equivalent dipole was localized more medially and deeper in the brain. The orientation of these major dipole activities was markedly different. These dipoles appeared to represent activity of distinct extrastriate areas, in contrast to earlier activity which was modelled by more posterior dipoles in the occipital lobe. The latter dipoles were at comparable contralateral locations and had similar peak activities around 100 ms, suggesting an origin in the striate cortex.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In our spatial attention task, healthy young subjects (N=W) attended selectively to the right or left half of bilateral stimulus arrays that were flashed in rapid sequence (Fig. 1, top). Attention was directed covertly while the subjects' gaze remained fixated on a central dot; ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 231 (1984), S. 1-5 
    ISSN: 1432-1459
    Keywords: Brain-stem auditory-evoked potentials ; Brainstem disorders ; Closed head trauma ; Coma ; Hearing disorders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Akustisch evozierte Hirnstammpotentiale (AEHP) wurden bei 35 post-komatösen Patienten nach schwerem Schädelhirntrauma (SHT) abgeleitet. Bezogen auf die an 30 Kontrollpersonen ermittelten Normewerte konnten nur in 2 Einzelfällen signifikante Veränderungen des AEHP bestimmt werden. Dies war jedoch nur wegen eines abnormalen Seitenunterschieds, nicht aber aufgrund verlängerter Interpeak-Latenzen oder erniedrigtem Amplitudenverhältnis V/I möglich. Die Patientengruppe zeigte bei normalen Interpeak-Latenzen eine generelle Amplitudenreduktion, am ausgeprägtesten bei den Patienten mit Hörminderung. Das AEHP erscheint somit nicht hinreichend geeignet, strukturelle, nach dem SHT fortbestehende Hirnstammläsionen im Einzelfall nachzuweisen. Vermutlich ist dabei das neurale Substrat, das die Wellen IV und V des AEHP generiert, nicht auf Dauer geschädigt. Die beobachtete Amplitudenreduktion ist eher auf diffuse cochleäre Schädigungen, die im Zusammenhang mit dem SHT bekannt sind, zurückzuführen.
    Notes: Summary Brain-stem auditory-evoked potentials (BAEPs) were recorded in 35 post-comatose patients after severe closed head trauma. Compared to the normal BAEPs obtained from 30 normal controls, significant individual abnormality could be detected in only 2 patients. This abnormality consisted of lateral asymmetry, but not prolonged interpeak latencies or abnormal amplitude ratios. Further, no differences were found between groups as regards interpeak latencies. A significant reduction of BAEP amplitudes was seen in the patient group, being most pronounced in the 13 patients with hearing loss. It is concluded that the BAEP does not sufficiently reveal brainstem lesions expected to persist after severe closed head trauma, presumably because the structures generating waves IV and V are not permanently affected. The amplitude reductions observed may be explained by the diffuse cochlear damage known to occur concurrently with head trauma.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Brain topography 5 (1993), S. 419-423 
    ISSN: 1573-6792
    Keywords: Brain source imaging ; Regional source scanning ; Spatio-temporal dipole model ; Dipole localization ; Epileptic spikes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two categories of models are available for the functional imaging of scalp recorded electric brain activity: single-time-point and spatio-temporal. Instantaneous models require strict assumptions that do not conform with the underlying physiology, because they rely on the few voltage differences measured at only one sampling point. Spatio-temporal models create a spatial image of discrete multiple sources and a temporal image of source current wave forms which reflect the time course of the local activity in circumscribed brain areas at a macroscopic level. The spatial image may be limited in accuracy because it depends both on model and data, but it can be validated by scanning the brain with regional dipole sources. In many cases of temporal lobe epilepsy, for example, interictal spikes can be described adequately by as few as two equivalent dipoles, which image the vertical source current arising from the medio-basal aspect of the temporal lobe and the horizontal source current from its lateral surface.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...