MRI/DTI of the brain stem reveals reversible and irreversible disruption of the baroreflex neural circuits: Clinical implications

Chia Hao Su, Ching Yi Tsai, Alice Y.W. Chang, Julie Y.H. Chan, Samuel H.H. Chan*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

14 Scopus citations

Abstract

Baroreflex is the physiological mechanism for the maintenance of blood pressure and heart rate. Impairment of baroreflex is not a disease per se. However, depending on severity, the eventuality of baroreflex dysfunction varies from inconvenience in daily existence to curtailment of mobility to death. Despite universal acceptance, neuronal traffic within the contemporary neural circuits during the execution of baroreflex has never been visualized. By enhancing signal detection and fine-tuning the scanning parameters, we have successfully implemented tractographic analysis of the medulla oblongata in mice that allowed for visualization of connectivity between key brain stem nuclei in the baroreflex circuits. When viewed in conjunction with radiotelemetric analysis of the baroreflex, we found that under pathophysiological conditions when the disrupted connectivity between key nuclei in the baroreflex circuits was reversible, the associated disease condition (e.g. neurogenic hypertension) was amenable to remedial measures. Nevertheless, fatality ensues under pathological conditions (e.g. hepatic encephalopathy) when the connectivity between key substrates in the baroreflex circuits was irreversibly severed. MRI/DTI also prompted partial re-wiring of the contemporary circuit for baroreflex-mediated sympathetic vasomotor tone, and unearthed an explanation for the time lapse between brain death and the inevitable asystole signifying cardiac death that follows.

Original languageEnglish
Pages (from-to)837-848
Number of pages12
JournalTheranostics
Volume6
Issue number6
DOIs
StatePublished - 2016
Externally publishedYes

Bibliographical note

Publisher Copyright:
© Ivyspring International Publisher.

Keywords

  • Baroreflex-mediated vasomotor tone
  • Brain death
  • Cardiac vagal baroreflex
  • Hepatic encephalopathy
  • Neural circuits
  • Neurogenic hypertension
  • Neuroimaging

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