We have recently initiated in CCL the use of eyeblink conditioning in human subjects. This is an example of so called classical or Pavlovian conditioning. A subject receives a neutral stimulus (e.g. a tone) followed after a few hundred milliseconds by a puff of air to the eye. The tone does not evoke any response but the air puff elicits a blink. After a number of paired presentations of tone and air puff, the tone will elicit a blink that will reach its maximum close to the onset of the air puff. This response is adaptively timed, which means that if the interval between tone and air puff is increased, the delay of the conditioned blink will, after some additional training, be increased by a corresponding amount, so that the conditioned response will again coincide with the air puff where the protective effect is maximal.
The experimental setup was developed in collaboration with a research group in Rotterdam’s Erasmus University. The subject wears a bicycle helmet that contains equipment for delivering stimuli and recording blinks. The blink is monitored by fastening a very small magnet on the eyelid and measuring changes in the magnetic field caused by eyelid movements. Sound stimuli are delivered through earphones and a thin flexible tube delivers the air puff. A film can be shown in miniature screens just in front of the eyes.