Dissociation of temporal dynamics of heart rate and blood pressure responses elicited by conditioned fear but not acoustic startle.
Fear-inducing stimuli were hypothesized to elicit fast heart rate (HR) responses but slow mean arterial blood pressure (MAP) responses and thus were studied in auditory fear conditioning and acoustic startle at high temporal resolution in freely moving mice and rats. Fear-induced instantaneous acceleration of HR reaching maximum physiological values and subsequent recovery to baseline were observed. The MAP response consisted of an immediate, mild, and transient increase followed by a sluggish, profound elevation and slow recovery. HR and MAP responses served as reliable indicators of conditioned fear in mice with dissociated temporal dynamics. Unconditioned auditory stimuli, including acoustic startle stimuli, elicited only fast, mild, and transient MAP and HR elevations in mice and rats, reflecting arousal and attention under these experimental conditions.
Tovote
Philip
P
Department of Molecular Neuroendocrinology, Max Planck Institute for Experimental Medicine, Goettingen, Germany.
Meyer
Michael
M
Pilz
Peter K D
PK
Ronnenberg
Anja
A
Ogren
Sven Ove
SO
Spiess
Joanchim
J
Stiedl
Oliver
O
D000161:Acoustic Stimulation; D000818:Animals; D001143:Arousal; D001288:Attention; D001794:Blood Pressure / Q000502:physiology*; D003214:Conditioning, Classical; D005239:Fear; D006339:Heart Rate / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D013216:Reflex, Startle / Q000502:physiology*