The interlick interval distribution of rats while ingesting maltose under real and sham feeding conditions and while ingesting seven concentrations of sucrose under real feeding conditions was analyzed. The analysis revealed that the licking behavior of rats is organized into bursts of licking at a high rate. These bursts occurred in clusters that were separated by brief (250-500 ms) interruptions. The clusters were separated by intervals that ranged from 500 ms to many hundreds of seconds. Sham feeding increased the length of the meal by increasing the number but not the size of the clusters. Increasing the concentration of sucrose increased monotonically the size of the clusters but varied the number of clusters as an inverted-V-shaped function. This analysis revealed the details of the central nervous system's control over ingestive behavior.

Analysis of the microstructure of the rhythmic tongue movements of rats ingesting maltose and sucrose solutions

Little is known about how specific genes influence taste function in mammals. One of the most promising ways to fill this void is to screen the progeny of chemically mutagenized (or genetically altered) mice for aberrant taste phenotypes and then identify the mutated gene(s) that is associated with each taste anomaly. To exploit this approach, a high-throughput and robust screening procedure is needed. We have attempted to meet this demand by developing an automated procedure that assesses taste responsiveness of individual mice to palatable and unpalatable taste stimuli. We focused on three taste stimuli (quinine hydrochloride, QHCl; sodium chloride, NaCl; and sucrose) and one mouse strain (C57BL/6). We used a commercially available gustometer system that both monitors the licking responses of mice and controls the presentation of each taste stimulus during successive 5 s trials. We describe a screening procedure that (after 2 days of simple training) can generate a concentration-response curve for NaCl or sucrose during a single 30 min test session, and for QHCl over three 30 min test sessions. A normative database based on the responses of 98 mice subjected to our screening procedure is also presented. We envision that investigators could use this normative database to assess taste function in the progeny of mutagenized (or genetically altered) mice. Any mouse that deviates significantly-e.g. three standard deviations (SD)-from the mean of the normative database would be flagged as having a potentially interesting mutation. We also developed an additional second screen for identifying mice with oromotor abnormalities. This latter screen is necessary because oromotor problems could lead to false positives or negatives in the screen for taste function, but is also useful for researchers interested in genes influencing oromotor circuitry. Throughout the development of the screening protocol, we sought to balance two conflicting demands: the need to maximize the screen's sensitivity and minimize its duration. This screen represents a significant improvement over the common two-bottle preference test because it assesses taste function more specifically and in a fraction of the time.

/pdf/a-high-throughput-screening-procedure-for-identifying-mice-3mec6pu4qa.pdf

A high-throughput screening procedure for identifying mice with aberrant taste and oromotor function.

Aversive stimulus properties of drugs.

Animals have developed a range of drinking strategies depending on physiological and environmental constraints. Vertebrates with incomplete cheeks use their tongue to drink; the most common example is the lapping of cats and dogs. We show that the domestic cat (Felis catus) laps by a subtle mechanism based on water adhesion to the dorsal side of the tongue. A combined experimental and theoretical analysis reveals that Felis catus exploits fluid inertia to defeat gravity and pull liquid into the mouth. This competition between inertia and gravity sets the lapping frequency and yields a prediction for the dependence of frequency on animal mass. Measurements of lapping frequency across the family Felidae support this prediction, which suggests that the lapping mechanism is conserved among felines.

https://science.sciencemag.org/content/sci/330/6008/1231.full.pdf

How Cats Lap: Water Uptake by Felis catus

Licking behavior in the rat: measurement and situational control of licking frequency.

A contact-sensitive electronic instrument was described by Pilgrim (1948), but it was only after the publication of “An electronic drinkometer” (Hill and Stellar, 1951) that contact sensors became routine tools in studies requiring the recording of water intake. These devices are still commonly referred to as drinkometers; however, preference here will be given to the terms lick or contact sensors. The principle of the device is simple. One lead from the instrument makes contact with the drinking tube; the other one goes to the metal floor of the test chamber. Each time the animal completes the circuit, switching is accomplished in the output circuit of the sensor, and the switch can be used for counting or for some other means of registration.

The Recording of Licking Behavior

Accidental discoveries can lead to extensive research programs. Two lines or research into the reinforcing properties of oral sensory stimulation have resulted directly from such serendipitous observations: the study of airlicking (Hendry and Rasche, 1961) and of current-licking behavior (Slangen and Weijnen, 1972).

Jan A. W. M. Weijnen

Papers

Licking behavior in the rat: measurement and situational control of licking frequency.

The Recording of Licking Behavior

Current Licking: Lick-Contingent Electrical Stimulation of the Tongue