Neuronal linking of voluntary saccades and visual perception
High frequency (gamma) changes in the EEG are related to saccadic eye movements performed voluntarily or cued by different auditory and visual stimuli or without eye movements (covert visuo-spatial attention).
Microelectrode studies established that "gamma" frequency, roughly around 40 Hz, reflects synchronization of distinct neuronal groups and their functional binding. We study the non-visual, dynamic role of the gamma component of the EEG when voluntary saccades are performed. Our experiments with blindfolded subjects (thereby decoupling saccades from visual input) yield data that show power in the gamma frequency of the human EEG is modulated by voluntary saccades. We interpret these results as suggesting that gamma is a mechanism of short-term plasticity which is needed for predictive control in motor-sensory interaction.
Parkinson's Disease (PD) affects some 1 to 2 percent of the population, with increasing frequency with age. Traditionally, PD, a dopaminergic deficiency disorder of the basal ganglia, has been associated with motor impairment. It is known that the interaction of the basal ganglia with various cortices is essential for executing planned behaviour. The focus of our study is that predictive cortical control, associated with voluntary saccadic eye movements suffers in PD due to inefficient basal ganglia-cortical oculomotor loops involved in predictive motor-sensory control. It has been proposed that the link between voluntary effort, sensory input and sequencing of motor movements or thought suffer in PD due to a deficient role of the basal ganglia in neuronal binding. Our question concerns whether the known abnormality of saccadic eye movements in PD is associated with deficient intrasaccadic gamma.
Recent PublicationsParkinson's Disease and Nonmotor Dysfunction R.Pfeiffer and I.Bodis-Wollner (eds) Totowa, New Jersey: Humana Press 2005
Bodis-Wollner I (2003) Neuropsychological and perceptual defects in Parkinson’s disease. Parkinsonism and Related Disorders Suppl2:83-91.
Bodis-Wollner I., Von Gizycki H, Avitable M, Hussain Z, Javeid A, Habib, A, Raza A and Sabet M ,(2002). Perisaccadic occipital EEG changes qualified with wavelet analysis. Ann. N.Y.Acad.Sci. 956; 464-467.
Bodis-Wolner I, Bucher SF, Seelos KC. (1999). Cortical activation patterns during voluntary blinks and voluntary saccades. Neurology 53:1800-1805
Bodis-Wollner I, Bucher SF, Seelos KC, Paulus W, Reiser M and Oertel WH (1997). Functional MRI mapping of occipital and frontal cortical activity during voluntary and imagined saccades. Neurology 49:416-420.
Service FunctionsFellow, Hanse Institute for Advanced Studies, (HWK) Delmenhorst, Germany 2002-2003, 2004-
Hungarian Academy of Sciences, May 2002
