Direction of saccadic and smooth eye movements induced by electrical stimulation of the human frontal eye field: effect of orbital position
- 89 Downloads
The present study reports on the direction of saccadic and smooth eye movements, which were induced electrically from the human dorsolateral frontal cortex including the human frontal eye field (FEF). The eye position prior to stimulation was varied in order to examine its effect on induced eye movement direction. The five patients of the study underwent invasive presurgical evaluation for pharmacoresistant epilepsy. The present data show that the direction of electrically induced eye movements was always contralateral and either horizontal or oblique upward if the eye started from the primary position. The elicited direction was changed if the eyes started from an eccentric position. The frequency of oblique eye movements was increased and oblique downward responses were induced, which were not observed if the eye started from the primary position. This was found for saccades and, especially, for smooth eye movements. Head movements, which were almost exclusively induced with saccades, did not depend on initial orbital position. Four conclusions can be drawn. Firstly, saccades and smooth eye movements induced from the human dorsolateral cortex including the human FEF have the same directional bias. Secondly, the frequent upward responses and the absence of downward responses induced from the primary position suggests either a more numerous or a more superficial representation of neurons that code for the former direction. Thirdly, at some sites the direction of saccades and smooth eye movements varies depending on the initial orbital position. Since these directional changes were observed without changes in eye-head coordination, our data suggest that stimulation of the FEF might evoke goal-directed saccades or interferes with a resettable saccade integrator. Fourthly, human studies that investigate eye movements induced from the lateral frontal cortex need to control eye position prior to stimulation.
KeywordsSaccades Smooth eye movements Frontal eye field Human Electrical stimulation
This work was supported by the Swiss National Science Foundation (Grant No. 3100-067105.01, 3100-067874.02, 3100-65232.01, 3100-068105.02). The authors thank L. Spinelli and S. Perrig for technical help.
- Blanke O, Spinelli L, Michel CM, Thut G, Landis T, Seeck M (1999) Human frontal eye fields: eye-head gaze movements induced by electrical stimulation at different orbital positions. Soc Neurosc Abstr 25:567Google Scholar
- Bruce CG (1990) Integration of sensory and motor signals in primate frontal eye fields. In: Edelman GM, Gall WE, Cowan WM (eds) Signal and sense: local and global order in perceptual maps. Wiley, New York, pp 261–314Google Scholar
- Förster O (1931) The cerebral cortex in man. Lancet 2:309–312Google Scholar
- Förster O (1936) Motorische Felder und Bahnen. In: Bumke O, Förster O (eds) Handbuch der Neurologie. Springer, Berlin Heidelberg New York, pp 46–141Google Scholar
- Gresty MA (1974) Coordination of head and eye movements to fixate continuous and intermittent targets. Vision Res 14:395–403Google Scholar
- Ojeman GA, Sutherling WW, Lesser RP, Dinner DS, Jayakar P, Saint-Hilaire JM (1993) Cortical stimulation In: Engel J (ed) Surgical treatment of the epilepsies. Raven Press, New York, pp 399–414Google Scholar
- Rasmussen T, Penfield W (1948) Movement of the head and eyes from stimulation of human frontal cortex. Res Publ Assoc Res Nerv Mental Dis 23:346–361Google Scholar
- Robinson DA (1975) Oculomotor control signals. In: Lennerstarnd G, Bach-y-Rita P (eds) Basic mechanisms of ocular motility and their clinical implications. Pergammon Press, Oxford, pp 337–374Google Scholar
- Robinson DA, Fuchs AF (1969) Eye movements evoked by stimulation of frontal eye fields. J Neurophysiol 32:637–648Google Scholar
- Schall JD (1998) Visuomotor areas areas of the frontal lobe. [Review]. In: Rockland K, Peters A, Kaas J (eds) Extrastriate visual cortex of primates, vol 12, cerebral cortex. Plenum, New York, pp 527–638Google Scholar