The recent finding of task-related theta oscillations in humans (M.J. Kahan
a, Sekuler, Caplan, Kirschen, Madsen, Nature 399 (1999) 781-784) raises a n
umber of questions. We recorded from 345 intracranial electrodes in five pa
tients with medically intractable epilepsy while they learned to navigate v
irtual mazes. Previously, we showed significant dependence of theta on two
different task parameters, maze difficulty and study versus test modes. Fir
st, we show that these results hold for an additional 174 electrodes and tw
o subjects, removing a previous confound between the two comparisons. Here
we ask whether or not these two task parameters reflect some common, or cor
related, task-correlates of theta. (C) 2000 Elsevier Science B.V. All right
s reserved.