Excitatory and inhibitory conditioning of two physiological responses in agroup of rats

A differential conditioning of 120 essays was carried out in a four-day per iod in a group of rats. The stimuli were the following: a light (CS-), a to ne (CS+) and an electric discharge (US). After six days, the subjects we re randomly subdivided into different groups. Each of the groups was submitte d in the trial phase to 15 occurrences of one of the following stimuli: CS, CS-, US, CS+/CS- and the context. No significant differences were found a t the lymphocyte response level (p<0,05). Regarding the protein amount, alm ost all groups showed higher indexes than the control group. However, only the group submitted to the excitatory stimulus show differences when compar ed with the control group. In the discussion over the results, two main fac tors are stressed: the significance of contextual clues in the modification of physiological responses and the importance of inhibitory stimuli in bal ancing the effects of excitatory conditioning.