Limits on activation-induced temperature and metabolic changes in the human primary visual cortex

Rachel Katz-Brull, David C. Alsop, Robert P. Marquis, Robert E. Lenkinski

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Changes in cerebral blood flow (CBF) and metabolism are now widely used to map and quantify neural activity, although the underlying mechanism for these changes is still incompletely understood. Magnetic resonance spectroscopy (MRS) at 3T, synchronized with a 32-s block design visual stimulation paradigm, was employed to investigate activation-induced changes in temperature and metabolism in the human primary visual cortex. A marginally significant increase in the local temperature of the visual cortex was found (0.1°C, P = 0.09), excluding the possibility of a temperature decrease (95% confidence interval (CI) = 0.0-0.2°C), which was previously suggested. A comparison with models of thermal equilibrium in the presence of blood flow suggests that an increase in heat production during activation, greater than or at least equal to that produced by the complete oxidative metabolism of the elevated glucose (Glc) utilization accompanying activation, would be required to offset the cooling effects of the increased blood flow. The total pools of glutamate (Glu), glutamine (Gln), myo-Inositol (ml), N-acetylaspartate (NAA), choline (Cho), and lactate (Lac) were not significantly affected by activation. Limits on Lac concentration changes were too weak to constrain theories of the metabolic use of elevated Glc consumption during stimulation, and emphasize the challenges of measuring even large Lac changes accompanying stimulation.

Original languageEnglish (US)
Pages (from-to)348-355
Number of pages8
JournalMagnetic Resonance in Medicine
Volume56
Issue number2
DOIs
StatePublished - Aug 2006

Fingerprint

Visual Cortex
Lactic Acid
Temperature
Cerebrovascular Circulation
Glucose
Photic Stimulation
Thermogenesis
Inositol
Choline
Glutamine
Glutamic Acid
Magnetic Resonance Spectroscopy
Hot Temperature
Confidence Intervals

Keywords

  • Brain activation
  • Cerebral blood flow
  • Magnetic resonance spectroscopy
  • N-acetylaspartate
  • Temperature

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Limits on activation-induced temperature and metabolic changes in the human primary visual cortex. / Katz-Brull, Rachel; Alsop, David C.; Marquis, Robert P.; Lenkinski, Robert E.

In: Magnetic Resonance in Medicine, Vol. 56, No. 2, 08.2006, p. 348-355.

Research output: Contribution to journalArticle

Katz-Brull, Rachel ; Alsop, David C. ; Marquis, Robert P. ; Lenkinski, Robert E. / Limits on activation-induced temperature and metabolic changes in the human primary visual cortex. In: Magnetic Resonance in Medicine. 2006 ; Vol. 56, No. 2. pp. 348-355.
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