Autonomic arousal in an appetitive context in primates: a behavioural and neural analysis

Abstract

Central to many emotional responses is the accompanying peripheral somatic and autonomic arousal, feedback from which has been hypothesized to enhance emotional memory and to contribute to appraisal processes and decision making, and dysfunction of which may contribute to antisocial behaviour. Whilst peripheral arousal may accompany both positive and negative emotional contexts, its relationship with the former is poorly understood, as are the neural mechanisms underlying such a relationship. The purpose of the present study was to determine the autonomic correlates of anticipation, as well as consumption, of high incentive food, in the freely moving common marmoset and to investigate the contribution of the amygdala to such effects. Blood pressure (BP) and heart rate (HR) were measured remotely by a telemetric device implanted into the descending aorta and behavioural responses were monitored whilst marmosets viewed preferred or non-preferred foods and were then allowed access to eat those foods. A marked rise in blood pressure in unrestrained marmosets was observed in response both to the sight of highly preferred foods (anticipatory period) as well as during the actual consumption of those foods (consummatory period). Excitotoxic lesions of the amygdala abolished the autonomic arousal in the anticipatory period, but spared both the behavioural arousal in the anticipatory period and the autonomic arousal in the consummatory period. Together these data serve as an important step towards understanding the role of autonomic arousal in emotion and its neural underpinnings.

Dopaminergic and non-dopaminergic value systems in conditioning and outcome-specific revaluation

“…The model also replicated observations showing that the blood pressure response is conditionable (Braesicke et al, 2005). In addition, the model predicts that the magnitude of BPRs tracks reward magnitude.…”

“…The taste-specific habituation of GUS inputs, m X , is a second mechanism of food specific satiety (FSS) that complements the model's "drive reduction" mechanism. This second mechanism of FSS can explain the observation that the kind of FSS that is assessed by actual consumption rather than by CS preference remains intact even after ORB and AMYG lesions (Hatfield et al, 1996;Dunn and Everitt, 1988 (Brown et al, 2004;Equation (9) (Braesicke, et al 2005). This influence is relayed from the hypothalamus to cardiovascular regulatory neurons in the medulla (Smith et al, 1990;Nakamura et al, 1992;Zhang et al, 2005Zhang et al, , 2006.…”

“…3, experimental results on BP and saccadic RTs are presented alongside model simulations of signals that predict these variables. (Nakamura et al, 1992;Braesicke et al, 2005). Motivational influences on saccadic reaction time are reproduced using incentive value signals broadcast by orbitofrontal cortex (Lauwereyns et al, 2002;Roesch and Olson, 2003).…”

“…3a: Simulated blood pressure output (right) compared with recorded blood pressure (left) during CS Task performance [Reprinted with permission from Nakamura et al (1992)]. Small increases in blood pressure follow the presentation of conditioned stimuli, unconditioned stimuli, or the consumption of unconditioned stimuli, but not neutral stimuli (Braesicke, et al 2005;Nakamura et al, 1992). 3b: Simulated saccadic reaction times (right) replicate trends in observed changes in saccadic reaction time [Reprinted with permission from Roesch and Olson (2003)].…”

Neural dynamics underlying impaired autonomic and conditioned responses following amygdala and orbitofrontal lesions.

“…Bars reflect average CMA cell activity across the two second US presentation before (white) and after FSS (black). (C) Consumption of a valued food is associated with an increase in systolic blood pressure for both intact (white) and amygdala-lesioned animals (black; reprinted with permission from Braesicke et al, 2005). Bars indicate increase in blood pressure relative to resting systolic blood pressure.…”