Classically conditioned bradycardia and skeletal-motor activity in restrained rats

Pharmacological dissociation of heart rate and somatomotor components of the orienting response

“…Especially in the realms of attention and learning, these bounds have been clearly identificd. Conditioned changes in HR, for example, appear not to be skeletomotor artifacts (Fitzgerald, Stainbrook, & Francisco, 1985;Martin & Fitzgerald, 1980). This study, especially when it is considered in light of previous work on the OR (e.g., Daileyet al, 1986;Siegel et al, 1987), indicates that the HR OR, too, is not simply a product of skeletomotor behavior.…”

Attenuation of the bidirectional effects of chlordiazepoxide and FG 7142 on conditioned response suppression and associated cardiovascular reactivity by loss of cortical cholinergic inputs

“…Although the typical response of rats to a conditioned aversive stimulus is cardioacceleration (e.g., Hunt et al 1994;Iwata and LeDoux 1988;Kurtz and Campbell 1994), deceleratory responses have been reported, especially in association with somatic "freezing" (Fitzgerald et al 1985;Hunt et al 1997). In view of the profound behavioral suppression to the CS in both control and lesion groups, cardiac deceleration to this stimulus may have been confounded with reduced somatomotor activity (Obrist et al 1975;Black and de Toledo 1972) and/or coactivation of the parasympathetic system (Iwata and LeDoux 1988;Hunt et al 1997).…”

Developmental constraints on the expression of behavioral and heart‐rate orienting responses: I. The role of cardiosomatic coupling

“…Similarly, Siege1 et al (1987) observed significant decreases in heart rate in 20to 21-day-old rats exposed to either olfactory, auditory, or visual stimuli even though all stimuli elicited a number of behavioral responses. Furthermore, Fitzgerald, Stainbrook, and Francisco, (1985) reported significant heart-rate decelerations in adult rats even during periods when they were behaviorally active.…”