Pain Medicine  |   October 2018
Incisional Nociceptive Input Impairs Attention-related Behavior and Is Associated with Reduced Neuronal Activity in the Prefrontal Cortex in Rats
Author Notes
  • From the Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, North Carolina.
  • Submitted for publication November 15, 2017. Accepted for publication April 26, 2018.
    Submitted for publication November 15, 2017. Accepted for publication April 26, 2018.×
  • Address correspondence to Dr. Ririe: Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157-1009. dririe@wakehealth.edu. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Pain Medicine / Basic Science / Central and Peripheral Nervous Systems / Pain Medicine / Pharmacology / Opioid
Pain Medicine   |   October 2018
Incisional Nociceptive Input Impairs Attention-related Behavior and Is Associated with Reduced Neuronal Activity in the Prefrontal Cortex in Rats
Anesthesiology 10 2018, Vol.129, 778-790. doi:10.1097/ALN.0000000000002325
Anesthesiology 10 2018, Vol.129, 778-790. doi:10.1097/ALN.0000000000002325
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • Cognitive capabilities may be impaired in the postoperative period

  • Impaired cognition may affect the patient’s ability to perform activities of daily living

What This Article Tells Us That Is New:

  • In a rat model of incisional pain, attention was impaired after injury and improved with an opioid analgesic

  • Diminished activity of the medial prefrontal cortex was found and may contribute to pain-induced impaired attention

Background: Cognitive capacity may be reduced from inflammation, surgery, anesthesia, and pain. In this study, we hypothesized that incision-induced nociceptive input impairs attentional performance and alters neuronal activity in the prefrontal cortex.

Methods: Attentional performance was measured in rats by using the titration variant of the 5-choice serial reaction time to determine the effect of surgical incision and anesthesia in a visual attention task. Neuronal activity (single spike and local field potentials) was measured in the medial prefrontal cortex in animals during the task.

Results: Incision significantly impaired attention postoperatively (area under curve of median cue duration-time 97.2 ± 56.8 [n = 9] vs. anesthesia control 25.5 ± 14.5 s-days [n = 9], P = 0.002; effect size, η2 = 0.456). Morphine (1 mg/kg) reduced impairment after incision (area under curve of median cue duration-time 31.6 ± 36.7 [n = 11] vs. saline 110 ± 64.7 s-days [n = 10], P < 0.001; η2 = 0.378). Incision also decreased cell activity (n = 24; 1.48 ± 0.58 vs. control, 2.93 ± 2.02 bursts/min; P = 0.002; η2 = 0.098) and local field potentials (n = 28; η2 = 0.111) in the medial prefrontal cortex.

Conclusions: These results show that acute postoperative nociceptive input from incision reduces attention-related task performance and decreases neuronal activity in the medial prefrontal cortex. Decreased neuronal activity suggests nociceptive input is more than just a distraction because neuronal activity increases during audiovisual distraction with similar behavioral impairment. This suggests that nociceptive input and the medial prefrontal cortex may contribute to attentional impairment and mild cognitive dysfunction postoperatively. In this regard, pain may affect postoperative recovery and return to normal activities through attentional impairment by contributing to lapses in concentration for routine and complex tasks.