Diurnal variation in baseline human regional cerebral blood flow demonstrated by PET

Journal Article · Sun May 01 04:00:00 EDT 1994 · Journal of Nuclear Medicine

OSTI ID:197906

Diehl, D J; Mintun, M A; Moore, R Y ^[1]

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1. Univ. of Pittsburgh, PA (United States); and others

We have previously described the diurnal variation in regional cerebral blood flow (rCBF) response to bright light in human subjects as demonstrated by the positron emission tomography (PET) activation method. In this abstract, we report the differences in rCBF (an indicator of differences in regional neuronal activity) between the evening and midday dim light baseline scans which served as the control states in the above bright light activation study. Five right-handed, healthy volunteers underwent both an evening (8pm) and a midday (12N) O-15 water PET scanning session. Each scanning session was preceded by one hour of dim light adaptation (50 lux) and consisted of six rCBF scans at three different light intensities in an AABBCC sequence (A=50 lux, B=2500 lux, C=7000lux). Significant differences in rCBF between the evening and midday 50 lux states were identified using the statistical parametric mapping method developed by Friston et al (p<.001). The evening scans demonstrated areas of greater relative blood flow in the pineal gland, the lateral temporal cortex bilaterally, the right lateral prefrontal cortex, the superior aspect of the anterior cingulate, and the left thalamus. The midday scans showed areas of greater relative blood flow in the visual cortex, the left lateral prefrontal cortex. the inferior aspect of the anterior cingulate, the left parietal cortex and the cerebellum. Our results demonstrate an extensive diurnal variation in baseline human rCBF. This indicates that time of day may be an important variable in conducting and interpreting functional brain imaging studies. Furthermore, these results suggest possible neuroanatomical substrates through which the circadian system may regulate the various physiologic and behavioral processes that manifest circadian rhythms.

• OSTI ID: 197906
• Report Number(s): CONF-940605--
• Journal Information: Journal of Nuclear Medicine, Journal Name: Journal of Nuclear Medicine Journal Issue: Suppl.5 Vol. 35; ISSN JNMEAQ; ISSN 0161-5505
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
BLOOD FLOW
BRAIN
CEREBELLUM
DAILY VARIATIONS
MELATONIN
PINEAL GLAND
POSITRON COMPUTED TOMOGRAPHY
THALAMUS