Personality and the topography of the conditioned eyelid response

One-hundred and four women were tested on an eyelid conditioning paradigm in a 2 x 2 x 2 factorial design where two levels of US intensity (1 vs 3 p.s.i.) were balanced against two rest pause interpolations (after 25 and after 50 trials), and the presence or absence of a warning stimulus prior to CS-US presentation. Subjects were later classified as high, low or intermediate extraverts on the basis of a personality questionnaire. A very detailed analysis of conditioned responses was carried out, using both simple and composite measures including work-ratio, utility-ratio, CR frequency, peak latency, peak amplitude, response area and effective response area, degree of avoidance amplitude and latency, etc. Major findings related to similar effects of high intensity US vs low intensity US, and introversion vs extraversion; introverts react as if they were responding to more intense stimuli than extraverts. This finding cuts across other parameter variables, and supports Eysenck's formulation of personality-conditioning relationships in terms of higher cortical arousal in introverts as compared with extraverts.     

Differential acquisition,extinction, and reinstatement of conditioned suppression in mice

In animals, the reappearance of conditioned fear responses after extinction has been primarily investigated using single-cue conditioning paradigms. However, a differential paradigm can overcome several of the disadvantages associated with a single-cue procedure. In the present study, the reinstatement phenomenon was assessed in mice using a differential conditioned suppression paradigm. In a first phase, one conditioned stimulus (CS + ) was consistently paired with an unconditioned stimulus (US; footshock) while another CS (CS–) was not, resulting in selective suppression of previously trained instrumental behaviour during the CS + . After the extinction phase, half of the animals (reinstatement group) were presented with unsignalled USs, while the other half were not (control group). A differential return of conditioned responding was observed in the reinstatement group, but not in the control group. The implications of these findings for future conditioning research are discussed.     

Differential acquisition, extinction, and reinstatement of conditioned suppression in mice

In animals, the reappearance of conditioned fear responses after extinction has been primarily investigated using single-cue conditioning paradigms. However, a differential paradigm can overcome several of the disadvantages associated with a single-cue procedure. In the present study, the reinstatement phenomenon was assessed in mice using a differential conditioned suppression paradigm. In a first phase, one conditioned stimulus (CS + ) was consistently paired with an unconditioned stimulus (US; footshock) while another CS (CS-) was not, resulting in selective suppression of previously trained instrumental behaviour during the CS + . After the extinction phase, half of the animals (reinstatement group) were presented with unsignalled USs, while the other half were not (control group). A differential return of conditioned responding was observed in the reinstatement group, but not in the control group. The implications of these findings for future conditioning research are discussed.