Date: September 6, 2007

Speaker's Name, Affiliation:

Michel Cabanac, Ph.D.
University Laval, Quebec, Canada

Seminar Title:"Pleasure of taste and phylogeny"

Presiding Chair: Harry R. Kissileff, Ph.D.

Rapporteur: Kathleen L. Keller, Ph.D.

Attendees and their Affiliation:

Kathleen Keller	Columbia/Obesity Research Center
Harry Kissileff	Columbia/Obesity Research Center
Katherine Nomura	Columbia University
Roni Aviram-Friedman	Teacher's College
Katherine Halmi	Cornell
Jennifer Nasser	Obesity Research Center
Blandine LaFerrere	Obesity Research Center
Debra Zellner	Montclair State
Susan Ettinger	Obesity Research Center
Gerry Smith	Weill Medical College
Deniz Atalayer	U. of Florida
Allan Geleibter	Obesity Research Center
Amanda Hamilton	Rutgers
Karen Acroff	Brooklyn College
Anthony Sclafani	Brooklyn College
George Collier	Rutgers

Summary:(Provided by the Speaker)

If we accept what other humans tell us as evidence of their pleasures, we should always remember that this response is indirect evidence. This indirect evidence can also be relied upon to study taste and the experience of pleasure in animals. Experiments have shown that Mammalia (mammals), Aves (birds), Chelonia (turtles), and Squamates (reptiles) all give signs of emotion and sensory pleasure, similar to those given by humans. But, Urodeles (amphibians) and Anoura (bats) do not. In these later animals, taste responses appear to be a matter of reflex (unconscious in nature).

It may be concluded, therefore, that Mammals and Birds experience gustatory pleasure in a way similar to that of humans, i.e., tastes that are pleasurable indicate that they are also useful stimuli. If we follow this argument, we can hypothesize that the signals that control gustatory pleasures are the same in human and in rat. By this, studying gustatory function in the rat (and other animals) can help us learn more about these responses in humans.

Consciousness emerged with the reptilian ancestors of present-day, turtles and lizards/snakes. Amphibians (and below) do not know sensory pleasure as they lack consciousness.

Discussion:

Q. Q. Does it (allisthesia) change the intensity of a sensation? Can you present sweet stimuli to a subject, and eventually get changes in the perception and detection of that stimulus?
A. I suppose it's possible, but I'm only interested in pleasure, not perception or detection.

Q. For the three exercise groups that you present, are those different individuals? How much of what you are picking up is because people use scales differently?
A. Those people are compared to themselves.

Q. In your price & palatability experiments, is this money that you provided for them, or are they paying with their own money?
A. It is both. We gave them a set amount to participate in each session.

Q. If you had made the paradigm effort instead of money, do you think you would have received the same results. Would people work harder or put in more effort for a food that is more palatable?
A. Yes, we have done that experiment with pain in the lab, by making people squat against a wall (until they are in pain & have to stop). They will go on for longer if the reward is more palatable.

Q. If you look at animals that are exposed to drugs, and you manipulate weight on these animals (force them to lose or gain), do you think you would see similar responses with respect to effort? How does this relate to your data on a set-point?
A. I would say that animals and humans tend to work harder when they are in an unpleasant situation.

Q. What was the control (in the experiment when the speaker taught his bird to use a word to evoke a pleasurable or "bon" situation)? Did the bird use the word "good" opposed to a "non-good" situation?
A. Once the bird was able to use the word "good" for a situation that was newĄ­I had never used "good" for that situation. Thus, I concluded that he understood the concept of "good."

Q. Your second graph to the right, the one with reptiles. It doesn't look linear. Can you comment?
A. It is probably non-linear, but it is still statistically significant.

Q. How do you know that it's just not a memory problem? Maybe amphibians don't remember a taste, and thus do not form an aversion.
A. Well, memory implies having a mind. I believe they only have a subconscious.

Q. How was lithium injected?
A. IP injection.

Q. How do you know that lithium chloride is an appropriate toxin in amphibians?
A. I don't know. Because it works in birds, lizards, and mammals I suppose.

Q. Just because they (amphibians) did not respond to LiCl does not mean that they do not experience pleasure.
A. True, we can only rely on what we can observe.

Q. You can get allisthesia both orally, and when you ingest nutrients intragastrically, correct? Do you get more allisthesia when the person actually drinks the solution?
A. If possible, I try to use the tube to bypass the mouth in my experiments.

Q. Do you get a decline in sweet preference with repeated testing (if they are not ingesting any)?
A. No, not to my knowledge. Only if they are ingesting the nutrient. However, I have only tested up to 1.5 hours post-experiment, so I can't say beyond that.