The contact method: a simple technique for electrical self-stimulation without external leads.

The contact method: a simple technique for electrical self-stimulation without external leads. PHYSIOL. BEHAV. 11(S) 721-723, 1973.-Electrical currents to reward areas of the brain were administered without the use of external leads by utilizing a method conceptually similar to that of the electronic drinkometer. A wire brush connected to the intracranial electrode protudes above the rat's head. By lifting its head the rat can make contact between the brush and a stimulation plate mounted horizontally overhead. The stimulation circuit is completed through the contact of the rat's feet with a grounded metal floor. Current thresholds and stimulation rates obtained by this method were identical to those obtained by the conventional method of stimulation. Self-stimulation Wireless contacts Chronic access Rats THE PHENOMENON of electrical self-stimulation of the brain has been under intensive investigation during the past two decades, and a great deal of information has been gained concerning its neuroanatomical and physiological substrates and its relations to other kinds of motivated behavior [4,6,8]. On the other hand, little is known about the effects of positively reinforcing brain stimulation upon other behavioral and physiological processes. We are initiating a research program aimed at elucidating the effects of chronic unlimited access to rewarding intracranial stimulation as well as other positive reinforcements upon several behavioral and physiological variables such as social behavior , learning abilities, resistance to stress, and regulatory functions. There are several technical problems involved in experimental paradigms requiring prolonged periods of access of the experimental animal to electrical brain stimulation. Electrical leads are cumbersome, restrict movement, and severely limit the variety of environmental situations under which self-stimulation behavior can be studied. If the animal is allowed to turn around freely a swivel or commutai tor is necessary to prevent twisting of the leads [ 1, 2, 5 I. Wireless control via radio transmission to a miniature receiver and current source implanted into the animal circumvents the need for external leads but requires relatively complex electronic apparatus and is better suited for large laboratory animals such as monkeys [ 3,7,9]. In the present paper we describe a simple method for providing a source of stimulating current to rats with implanted electrodes without the use of external leads or radio transmission devices. The method is based upon the concept of the electronic drinkometer whereby the rat closes a circuit between a drinking spout and the floor of the cage whenever it contacts the …