Behavioural, electrocortical and spectrum power effects after intraventricular injection of thallium in rats

Marked behaVioural, electrocortical and ECoG spectrum power changes were seen after microinjection of several dose of thallium sulfate into the 3rd cerebral ventricle in rats. Low doses produced behavioural sedation and/or sleep accompanied by larger amplitude slower frequency ECoG potentials whereas after higher doses an initial period of behavioral sedation was followed by an intense stimulatory symptomatology, stereotyped and abnormal movements, wild running crisis and epileptogenic ECoG discharges or electrocortical flattening according to the dose used. Significant changes occurred also in total as well as single bands of ECoG spectrum power. In conclusion, intraventricular injection of thallium produces a rich pattern of behavioural and electrocortical changes, the nature of which depends on the dose and which allow to explain the neurotoxicological profile in man. These results provide evidence for occurrence of epileptogenic disorders as well as for other ECoG abnormalities in thallotoxicosis.