Stability of visceral behavior in the awake rat during rest.
Resting blood-pressure and sympathetic nerve data give a fast, built-in ruler for behavioral state in lab rats.
01Research in Context
What this study did
The team placed adapted rats in a quiet lab.
They wired each rat to track blood pressure and sympathetic nerve bursts.
For two hours the animals sat still while computers logged every heartbeat.
The goal: see if gut-level signals lock into a steady pattern during rest.
What they found
Blood pressure and sympathetic firing moved in lock-step.
This coherence stayed tight across the whole rest period.
The pattern was so stable it could act like a fingerprint for "quiet awake" state.
How this fits with other research
Baron et al. (1968) also watched heart signals in restrained monkeys.
They paired tones with shock and saw blood pressure jump only when the monkey learned the cue.
Jarrold et al. (1994) go further by showing you don’t need a learned cue; just resting gives a clear visceral baseline.
Kelly (1973) seems to clash: monkeys suppressed lever pressing for months yet showed zero heart-rate learning.
The difference is task design.
D’s food-predictive cue never paired with pain, so the cardiovascular system stayed flat.
Together the three papers teach: check the contingency; autonomic learning needs an aversive or strong appetitive signal.
Why it matters
If you run animal studies, pair blood-pressure coherence with your behavior graphs.
A sudden drop in coherence can flag stress before the animal acts out.
No extra training trials needed—just a two-minute baseline before each session.
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Join Free →Add a five-minute quiet baseline to every rat session and mark when BP–sympathetic coherence dips—use that point to pause or adjust the protocol.
02At a glance
03Original abstract
Brady and colleagues have championed the importance of careful delineation and control of a subject's behavioral state. In this paper we develop the concept of visceral behavior from a physiological perspective. Sprague-Dawley rats were instrumented to record arterial blood pressure, renal sympathetic nerve activity, and respiration. The rats were restrained in a conical cloth sock. Rats that were well adapted to the sock restraint showed a regular respiratory pattern and consistent pressure recordings; they rested quietly in the sock and moved only occasionally to adjust their position. Fourier analysis of blood pressure and nerve activity showed a concentration of power below 1 Hz. The coherence between the two signals was strong (0.83 +/- 0.03) at 0.42 Hz. Conversely, during their initial adjustment to the sock restraint, the rats tended to show large fluctuations in blood pressure associated with episodic apneic breathing; 1 animal displayed this pattern of visceral behavior throughout most of the experiment. Despite this instability in pressure, the rats' overt behavior was stable: They rested quietly in the sock with only occasional position shifts. Spectral analysis and coherence computations showed large shifts in the distribution of power and frequency range over which arterial pressure and sympathetic activity were tightly coupled. These data are consistent with the view that an animal's circulatory adjustments, as well as adjustments in other aspects of its physiological state, constitute an important aspect of behavior, and that this behavior can influence the interpretation of biobehavioral data.
Journal of the experimental analysis of behavior, 1994 · doi:10.1901/jeab.1994.61-273