Forty-Eight Hour Conditioning Produces a Robust Long Lasting Flavor Preference in Rats

Conditioned flavor preference (CFP) learning is a form of associative learning in ingestive behavior. CFP Learning can be rapid and produces preferences of varying strengths that can be exceptionally persistent. We sought to establish a method to produce a robust long-lasting CFP in rats. Rats were given 48-h access (conditioning) to a CS+ flavor (grape or cherry 0.05% Kool-Aid, counterbalanced) mixed with 8% glucose and 0.05% saccharin. In order to determine the strength of conditioning rats were given 14 consecutive days of 24-h access to CS+ and CS- flavors mixed only with 0.05% Kool-Aid and 0.05% saccharin (extinction), then further tested 34 days after the last extinction test (48 days post conditioning) for 2 consecutive days with the CS+ and CS-. We found that not only did the learned CFP fail to extinguish over 14 days of testing, but it also persisted for at least 48 days after conditioning. These data provide a method to produce a robust, long lasting and persistent CFP for use in future ingestive behavior research.

Behavioural and cognitive effects of oligofructose-enriched inulin in rats

The behavioural and cognitive effects of oligofructose-enriched inulin at the doses of 5 and 10% in the diet, orally ingested daily during 2 weeks, wereinvestigated using a functional observational battery (FOB) and the light extinction test in male Wistar rats. Control rats received a standard diet and were tested in the same test situations. The behavioural effects were assessed 2 d before and 14 d after the beginning of the treatment period and the cognitive effects were investigated after the administration period by lever-pressing activity and learning discrimination using the light extinction test paradigm. In general, the study demonstrated that oligofructose-enriched inulin at 5% in the diet, and particularly at 10% in the diet, caused relaxing-like effects, stimulated and increased the general activity and interest of the rats to the test environment. In addition, both doses of oligofructose-enriched inulin showed significant effects on learning discrimination in male rats, in comparison with the control diet. These results suggest that oligofructose-enriched inulin, particularly at the dose of 10 %, improves cognitive performances in the light extinction test and the well-being of male rats using the FOB.

Hemispheric function in disorganized type schizophrenia: performance on the Quality Extinction Test

We assessed hemisphere function in right-handed male chronic, disorganized type schizophrenic patients (N = 60, age range 18–45 years) using the Quality Extinction Test (QET), in comparison to 20 right-handed male healthy controls in the same age range. The QET analysis discriminated between the disorganized schizophrenic patients and the controls. QET results indicated that chronic schizophrenic patients were less sensitive to tactile stimuli in both hands as compared to controls. Furthermore, the sensitivity to tactile stimuli of the left hand was less than that of the right hand in the schizophrenic patients. In contrast, in the normal controls the sensitivity was similar in both hands. These results indicate possible right hemisphere dysfunction together with disturbance in interhemispheric transmission through the corpus callosum in chronic, disorganized type schizophrenic patients.

Tactile Extinction on Complex Stimulation in Normal Children

The Schwartz Quality Extinction Test was administered to 221 normal right-handed children aged 4 to 7 years to find out at what age their ability to perceive complex bimanual simultaneous stimuli stabilizes. Tactile extinction was present in some 4- and 5-yr.-old children and tended to disappear later. We found a significant difference in responses between 5- and 6-yr.-old children but no difference regarding side and sex at different ages. Among the principal theories regarding the pathogenesis of extinction, incomplete maturation of attentional mechanisms seems the one which better explains extinction in younger children.