What do anatomical substrates of conditioned taste aversion tell us about  treatment? Conditioned taste aversions (CTAs) or Garcia effect are a byproduct of feeling ill after we've consumed a certain food. These aversions is present even if the illness is not related to ingestion and are difficult to extinguish in humans. This makes sense in light of the fact that in model systems like the rat they are entrenched in brainstem circuitry (Mickley et al., 2011).

With such a deep association taking place, does the likelihood of extinguishing these aversions via cognitive therapy (e.g., CBT) decrease dramatically?  What would be a possible inroad into treating  human subjects with such an aversion?


  Mickley GA, Wilson GN, Remus JL, Ramos L, Ketchesin KD, Biesan OR, Luchsinger JR, &amp; Prodan S. (2011).  Periaqueductal gray c-Fos expression varies relative to the method of conditioned taste aversion extinction employed.  Brain Res.;1423:17-29. http://dx.doi.org/10.1016/j.brainres.2011.09.033
Your question presupposes that 'deep' (in the brainstem) is the same thing as difficult to extinguish. But the anatomical location doesn't tell us how difficult it is to unlearn a CTA. One reason CTAs are difficult to extinguish is because extinction relies upon exposure to the cue (taste, in this case). And not many animals (including humans) will voluntarily re-expose themselves to unpleasant tastes. The resistance to extinction usually claimed for CTAs is more likely due to avoidance behaviour, rather than anatomical location of the neuroplasticity involved. When CTAs are extinguished by forcing the animal to taste the cue (e.g,. by gavaging), extinction occurs at the same rate as other flavour preferences. Source: http://ses.library.usyd.edu.au/handle/2123/372

An implication for treating CTAs in humans (e.g., after chemotherapy) is that re-exposure to the taste will eventually be successful. Obtaining voluntary re-exposure in the patient might be achieved by counter-conditioning such as combining the taste with a sweet additive.