US PATENT No. 4373471

The Optical Lickometer is used to measure licking/drinking from a standard drinking tube.  It requires a Photocell Sensor (H20-93, H20-93A, or H20-94).  The sensor's LED emitter and receiver are mounted on either side of the module.  The light beam is "piped" via glass rods across a gap a the end of the tube.  The animal's tongue breaks the beam on each lick.

The drink tube is electrically isolated from the rest of the module.  Aversive shock may be delivered through the drink tube.  Licks may be measured while shock is being delivered without spurious current paths or interference.

Twenty-five licks per second can be recorded with a formed meniscus or when the animal is sucking even in moderately dense, translucent liquids.