Cognitive impairment in pain through amygdala-driven prefrontal cortical deactivation

J Neurosci. 2010 Apr 14;30(15):5451-64. doi: 10.1523/JNEUROSCI.0225-10.2010.

Abstract

Cognitive deficits such as impaired decision-making can be a consequence of persistent pain. Normal functions of the intact amygdala and prefrontal cortex are required for emotion-based decision-making that relies on the ability to assess risk, attribute value, and identify advantageous strategies. We tested the hypothesis that pain-related cognitive deficits result from amygdala-driven impairment of medial prefrontal cortical (mPFC) function. To do this, we used electrophysiological single-unit recordings in vivo, patch clamp in brain slices, and various behavioral assays to show that increased neuronal activity in the amygdala in an animal model of arthritis pain was accompanied by decreased mPFC activation and impaired decision-making. Furthermore, pharmacologic inhibition (with a corticotropin-releasing factor 1 receptor antagonist) of pain-related hyperactivity in the basolateral amygdala (BLA), but not central amygdala (CeA), reversed deactivation of mPFC pyramidal cells and improved decision-making deficits. Pain-related cortical deactivation resulted from a shift of balance between inhibitory and excitatory synaptic transmission. Direct excitatory transmission to mPFC pyramidal cells did not change in the pain model, whereas polysynaptic inhibitory transmission increased. GABAergic transmission was reduced by non-NMDA receptor antagonists, suggesting that synaptic inhibition was glutamate driven. The results are consistent with a model of BLA-driven feedforward inhibition of mPFC neurons. In contrast to the differential effects of BLA versus CeA hyperactivity on cortical-cognitive functions, both amygdala nuclei modulate emotional-affective pain behavior. Thus, this study shows that the amygdala contributes not only to emotional-affective but also cognitive effects of pain. The novel amygdalo-cortical pain mechanism has important implications for our understanding of amygdala functions and amygdalo-cortical interactions.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amygdala / drug effects
  • Amygdala / physiopathology*
  • Animals
  • Arthritis / complications
  • Arthritis / physiopathology
  • Cognition Disorders / complications
  • Cognition Disorders / physiopathology*
  • Decision Making / drug effects
  • Decision Making / physiology
  • Disease Models, Animal
  • In Vitro Techniques
  • Neural Inhibition / drug effects
  • Neural Inhibition / physiology
  • Neural Pathways / drug effects
  • Neural Pathways / physiopathology
  • Neuronal Plasticity / drug effects
  • Neuronal Plasticity / physiology
  • Neurons / drug effects
  • Neurons / physiology
  • Pain / complications
  • Pain / drug therapy
  • Pain / physiopathology*
  • Prefrontal Cortex / drug effects
  • Prefrontal Cortex / physiopathology*
  • Pyramidal Cells / drug effects
  • Pyramidal Cells / physiology
  • Rats
  • Receptors, Corticotropin-Releasing Hormone / antagonists & inhibitors
  • Receptors, Corticotropin-Releasing Hormone / metabolism
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology
  • gamma-Aminobutyric Acid / metabolism

Substances

  • Receptors, Corticotropin-Releasing Hormone
  • gamma-Aminobutyric Acid
  • CRF receptor type 1