Studies of the effect of corticotropin (ACTH) and adrenocortical hormones on the electrical activity of the brain are numerous. The effects of corticotropin, cortisone, and hydrocortisone are similar, and they are the reverse of those of desoxycorticosterone.*
Cortisone decreases brain excitability in normal rats, as measured by electroshock seizure threshold and pentylenetetrazol (Metrazol) seizure threshold.† It counteracts the depressive action on brain excitability of desoxycorticosterone2 in normal and adrenalectomized rats. In patients receiving cortisone and in subjects with normal EEG traces, it causes an increase of alpha frequency.4 In adrenalectomized rats and patients with an abnormal EEG or Addison's disease, the slow EEG returns to normal under cortisone treatment.‡
Hydrocortisone administered intravenously increases theta activity in normal and epileptic subjects, with increase in bilateral spike-wave discharges.7 The same abnormality has been observed in patients under cortisone treatment.8
The action of the hormones on brain excitability has