A modification of the dialytrode for simultaneous CNS recording and chemical stimulation.

Currently, chemical stimulation of the brain is done either with a single cannula that is inserted at the time the drug is delivered or with two cannulae that permit perfusion of the area of interest. The dialytrode is a push-pull cannula consisting of two concentric tubes, a porous membrane covering the tip of the tubing and a platinum wire loop that extends around the membrane and is used for EEG recordings. Studies with the dialytrode indicate that while the membrane is relatively impermeable to bacteria, molecules the size of neurotransmitters pass easily through the membrane. Therefore, the dailytrode is well suited for chronic chemical stimulation studies.