This chapter describes some previously published findings from pharmaco-behavioural studies, the explanation of which may require the postulation of a role for the glia. The viability of the hypotheses, but not their validity, rests on at least one demonstration that adequate stimuli associated with learning task give rise to alterations in the ionic state surrounding cells in the brain areas shown to be activated specifically during memory processing. The chapter discusses some recently reported and some unpublished data relevant to this issue.