Zusammenfassung
Einleitung: In dieser Studie wurden die neurophysiologischen Korrelate der bewussten Restwahrnehmung
für Bewegungsreize bei einem Patienten mit einer Läsion des primären Kortex nach einem
Insult im Versorgungsgebiet der A. cerebri posterior untersucht. Methodik: Das durch Bewegungsreize im hemianopen Gesichtsfeld evozierte Aktivitätsmuster wurde
mit Magnetenzephalographie und funktioneller Kernspintomographie untersucht. Ergebnisse: Die funktionelle Kernspintomographie zeigte, dass Bewegungsreize im hemianopen Gesichtsfeld
Aktivierungen im extrastriären visuellen Kortex der geschädigten Hemisphäre hervorgerufen
haben. Die Magnetenzephalographie zeigte, dass zunächst die hierarchisch höhere Region
V5 und danach die hierarchisch niedrigeren Regionen V2/V3 in der Nähe der Läsion aktiviert
wurden. Diskussion: Die Ergebnisse zeigen, dass Restwahrnehmung für Bewegung durch subkortikale Bahnen
vermittelt werden kann, die den primär visuellen Kortex umgehen.
Abstract
Introduction: The neurophysiological correlates of preserved vision for motion associated with
awareness were studied in a patient with a lesion of the striate cortex following
a posterior cerebral artery stroke. Method: Magnetencephalography was employed in conjunction with functional magnetic resonance
imaging to investigate the spatio-temporal pattern of neural activity elicited by
moving stimuli presented to the hemianopic field of the patient. Results: Functional magnetic resonance imaging showed that motion stimuli presented to the
hemianopic field produced activation in several extrastriate areas of the lesioned
hemisphere. Magnetoencephalographic recordings indicated that evoked activity occurred
earlier in the higher-tier visual area V5 than in the lower-tier areas V2/V3 adjacent
to the lesion. Discussion: The results suggest that preserved vision for motion is mediated by subcortical pathways
that bypass the primary visual cortex.
Key words
Riddoch syndrome - blindsight - PCA stroke - motion - MEG - fMRI
Literatur
1
Weiskrantz L, Warrington E K, Sanders M D, Marshall J.
Visual Capacity in the Hemianopic Field Following a Restricted Occipital Ablation.
Brain.
1974;
97
709-728
2
Riddoch G.
Dissociation of Visual Perceptions Due to Occipital Injuries, With Especial Reference
to Appreciation of Movement.
Brain.
1917;
40
15-57
3
Fendrich R, Wessinger C M, Gazzaniga M S.
Residual Vision in a Scotoma: Implications for Blindsight (See Comments).
Science.
27.11.1992;
258
1489-1491
4
Kaas J H, Krubitzer L A.
Area 17 Lesions Deactivate Area MT in Owl Monkeys.
VisNeurosci.
1992;
9
399-407
5
Scharli H, Harman A M, Hogben J H.
Blindsight in Subjects With Homonymous Visual Field Defects.
J Cogn Neurosci.
1999;
11
52-66
6
Kentridge R W, Heywood C A, Weiskrantz L.
Residual Vision in Multiple Retinal Locations Within a Scotoma: Implications for Blindsight.
The Journal of Cognitive Neuroscience.
1997;
9 (2)
191-202
7
Stoerig P, Kleinschmidt A, Frahm .
No visual responses in denervated V1: high-resolution functional magnetic resonance
imaging of a blindsight patient.
Neuroreport.
1998;
9 (1)
21-25
8
Barbur J L, Harlow A J, Weiskrantz L.
Spatial and Temporal Response Properties of Residual Vision in a Case of Hemianopia.
Philos Trans R Soc Lond B Biol Sci.
1994;
343
157-166
9
Sahraie A, Weiskrantz L, Barbur J L, Simmons A, Williams S C, Brammer M J.
Pattern of Neuronal Activity Associated With Conscious and Unconscious Processing
of Visual Signals.
Proc Natl Acad Sci USA.
1997;
94
9406-9411
10
Goebel R, Muckli L, Zanella F E, Singer W, Stoerig P.
Sustained Extrastriate Cortical Activation Without Visual Awareness Revealed by FMRI
Studies of Hemianopic Patients.
Vision Res.
2001;
41
1459-1474
11
Yukie M, Iwai E.
Direct Projection From the Dorsal Lateral Geniculate Nucleus to the Prestriate Cortex
in Macaque Monkeys.
J Comp Neurol.
1981;
201
81-97
12
Cowey A, Stoerig P, Bannister M.
Retinal Ganglion Cells Labelled From the Pulvinar Nucleus in Macaque Monkeys.
Neuroscience.
1994;
61
691-705
13
Standage G P, Benevento L A.
The Organization of Connections Between the Pulvinar and Visual Area MT in the Macaque
Monkey.
Brain Res.
1983;
262
288-294
14
Girard P, Salin P A, Bullier J.
Response Selectivity of Neurons in Area MT of the Macaque Monkey During Reversible
Inactivation of Area V1.
J Neurophysiol.
1992;
67
1437-1446
15
Rodman H R, Gross C G, Albright T D.
Afferent Basis of Visual Response Properties in Area MT of the Macaque. I. Effects
of Striate Cortex Removal.
J Neurosci.
1989;
9
2033-2050
16
Rodman H R, Gross C G, Albright T D.
Afferent Basis of Visual Response Properties in Area MT of the Macaque. II. Effects
of Superior Colliculus Removal.
J Neurosci.
1990;
10
1154-1164
17
Dineen J, Hendrickson A, Keating E G.
Alterations of Retinal Inputs Following Striate Cortex Removal in Adult Monkey.
Exp Brain Res.
1982;
47 (3)
446-456
18
Cowey A, Stoerig P, Williams C.
Variance in Transneuronal Retrograde Ganglion Cell Degeneration in Monkeys After Removal
of Striate Cortex: Effects of Size of the Cortical Lesion.
Vision Res.
1999;
39
3642-3652
19
Barbur J L, Watson J D, Frackowiak R S, Zeki S.
Conscious Visual Perception Without V1.
Brain.
1993;
116 (Pt 6)
1293-1302
20
Ffytche D H, Guy C N, Zeki S.
The Parallel Visual Motion Inputs into Areas V1 and V5 of Human Cerebral Cortex.
Brain.
1995;
118 (Pt 6)
1375-1394
21
Zeki S, Ffytche D H.
The Riddoch Syndrome: Insights into the Neurobiology of Conscious Vision.
Brain.
1998;
121 (Pt 1)
25-45
22
Goebel R, Khorram-Sefat D, Muckli L, Hacker H, Singer W.
The Constructive Nature of Vision: Direct Evidence From Functional Magnetic Resonance
Imaging Studies of Apparent Motion and Motion Imagery.
Eur J Neurosci.
1998;
10
1563-1573
23
Stoerig P, Cowey A.
Blindsight in Man and Monkey.
Brain.
1997;
120 (Pt 3)
535-559
24
Moore T, Rodman H R, Repp A B, Gross C G.
Localization of Visual Stimuli After Striate Cortex Damage in Monkeys: Parallels With
Human Blindsight.
Proc Natl Acad Sci USA.
1995;
92
8215-8218
25
Moore T, Rodman H R, Gross C G.
Direction of Motion Discrimination After Early Lesions of Striate Cortex (V1) of the
Macaque Monkey.
Proc Natl Acad Sci USA.
2001;
98 (1)
325-330
26
Rosa M G, Tweedale R, Elston G N.
Visual Responses of Neurons in the Middle Temporal Area of New World Monkeys After
Lesions of Striate Cortex.
J Neurosci.
2000;
20 (14)
5552-5563
Dr. med. Mircea Ariel Schoenfeld
Klinik für Neurologie II · Otto-von-Guericke-Universität Magdeburg
Leipzigerstraße 44
39120 Magdeburg
Email: ariel@neuro2.med.uni-magdeburg.de