Abstract. Examined the role of theta oscillations during spatial navigation learning vs completion. EEG data were recorded at 345 intracranial electrode sites in 5 patients with medically intractable epilepsy as they learned and then independently navigated virtual T-junction mazes.

Results show significant dependence of theta on the learning vs doing of mazes, that is, encoding vs retrieving processes.

Theta activity covaried with maze difficulty. The percentage of a trial time occupied by theta episodes was significantly greater for difficult than for easier mazes at 151 electrode sites. These two task manipulations did not relate strongly to the correlation map clusters. There was no decisive evidence found that these two task parameters affected theta in a separable way. Findings remove a previous confound between the two comparisons made in a previous study of the authors' (Kahana et al, 1999, Human theta oscillations exhibit task dependence during virtual maze navigation Nature 399 781-784).