Disruption of thalamic functional connectivity is a neural correlate of dexmedetomidine-induced unconsciousness

Elife. 2014 Nov 28;3:e04499. doi: 10.7554/eLife.04499.

Abstract

Understanding the neural basis of consciousness is fundamental to neuroscience research. Disruptions in cortico-cortical connectivity have been suggested as a primary mechanism of unconsciousness. By using a novel combination of positron emission tomography and functional magnetic resonance imaging, we studied anesthesia-induced unconsciousness and recovery using the α₂-agonist dexmedetomidine. During unconsciousness, cerebral metabolic rate of glucose and cerebral blood flow were preferentially decreased in the thalamus, the Default Mode Network (DMN), and the bilateral Frontoparietal Networks (FPNs). Cortico-cortical functional connectivity within the DMN and FPNs was preserved. However, DMN thalamo-cortical functional connectivity was disrupted. Recovery from this state was associated with sustained reduction in cerebral blood flow and restored DMN thalamo-cortical functional connectivity. We report that loss of thalamo-cortical functional connectivity is sufficient to produce unconsciousness.

Keywords: consciousness; cortico-cortical; default mode network; dexmedetomidine; functional connectivity; human; neuroscience; thalamo-cortical.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Analgesics, Non-Narcotic / pharmacology
  • Brain Mapping
  • Cerebral Cortex / blood supply
  • Cerebral Cortex / drug effects*
  • Cerebral Cortex / physiology
  • Consciousness / physiology
  • Dexmedetomidine / pharmacology
  • Electroencephalography
  • Female
  • Humans
  • Male
  • Nerve Net / blood supply
  • Nerve Net / drug effects*
  • Nerve Net / physiology
  • Neural Pathways / blood supply
  • Neural Pathways / drug effects*
  • Neural Pathways / physiology
  • Thalamus / blood supply
  • Thalamus / drug effects*
  • Thalamus / physiology
  • Unconsciousness / chemically induced*
  • Unconsciousness / physiopathology

Substances

  • Analgesics, Non-Narcotic
  • Dexmedetomidine