Abstract
Functional neuroimaging studies have shown that cognitive processes increase regional cerebral blood flow in relation with enhanced neuronal activity. However, cognition induces elevation of blood pressure, heart rate and respiratory rate, each of which also affects cerebral circulation. For proper interpretation of functional neuroimaging data, it is necessary to dissociate the effects of systemic and local metabolic reactions on regional cerebral circulation. To elucidate this interaction, we examined the changes in cerebral blood flow velocity, which were caused by voluntary hyperventilation-induced hypocapnia without cognitive effort and hypocapnia evolving during mental arithmetic task. The cerebral blood flow velocity was recorded in the middle cerebral arteries, using transcranial Doppler sonography. Respiratory rate, end-tidal partial pressure of CO2, heart rate and arterial blood pressure were simultaneously monitored. Data were statistically evaluated. Hypocapnia induced by voluntary hyperventilation without cognition decreased the cerebral blood flow velocity. During mental arithmetic, the cerebral blood flow velocity first increased, but the hypocapnia, which was induced by involuntarily hyperventilation related to cognitive effort, reduced it. This implies temporary vasoconstriction of cerebral microvessels, and the increase in cerebral vascular resistance index supports this finding. These results suggest that hypocapnia, which develops during cognition, may decrease blood flow velocity in the middle cerebral arteries, which interferes with the neuronal activity-driven regulation of cerebral circulation. In conclusion, when interpreting the results of functional neuroimaging studies on cognitive mechanisms, the tight coupling of the effects of mental processes and autonomic/metabolic reactions should be considered.
| Original language | English |
|---|---|
| Pages (from-to) | 147-154 |
| Number of pages | 8 |
| Journal | Tohoku Journal of Experimental Medicine |
| Volume | 217 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2009 |
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Keywords
- Blood pressure
- Heart rate
- Hypocapnia
- Mental arithmetic
- Transcranial Doppler sonography
ASJC Scopus subject areas
- Medicine(all)
- Biochemistry, Genetics and Molecular Biology(all)
Cite this
Hypocapnia induced by involuntary hyperventilation during mental arithmetic reduces cerebral blood flow velocity. / Debreczeni, Róbert; Amrein, Ilona; Kamondi, A.; Szirmai, I.
In: Tohoku Journal of Experimental Medicine, Vol. 217, No. 2, 2009, p. 147-154.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Hypocapnia induced by involuntary hyperventilation during mental arithmetic reduces cerebral blood flow velocity
AU - Debreczeni, Róbert
AU - Amrein, Ilona
AU - Kamondi, A.
AU - Szirmai, I.
PY - 2009
Y1 - 2009
N2 - Functional neuroimaging studies have shown that cognitive processes increase regional cerebral blood flow in relation with enhanced neuronal activity. However, cognition induces elevation of blood pressure, heart rate and respiratory rate, each of which also affects cerebral circulation. For proper interpretation of functional neuroimaging data, it is necessary to dissociate the effects of systemic and local metabolic reactions on regional cerebral circulation. To elucidate this interaction, we examined the changes in cerebral blood flow velocity, which were caused by voluntary hyperventilation-induced hypocapnia without cognitive effort and hypocapnia evolving during mental arithmetic task. The cerebral blood flow velocity was recorded in the middle cerebral arteries, using transcranial Doppler sonography. Respiratory rate, end-tidal partial pressure of CO2, heart rate and arterial blood pressure were simultaneously monitored. Data were statistically evaluated. Hypocapnia induced by voluntary hyperventilation without cognition decreased the cerebral blood flow velocity. During mental arithmetic, the cerebral blood flow velocity first increased, but the hypocapnia, which was induced by involuntarily hyperventilation related to cognitive effort, reduced it. This implies temporary vasoconstriction of cerebral microvessels, and the increase in cerebral vascular resistance index supports this finding. These results suggest that hypocapnia, which develops during cognition, may decrease blood flow velocity in the middle cerebral arteries, which interferes with the neuronal activity-driven regulation of cerebral circulation. In conclusion, when interpreting the results of functional neuroimaging studies on cognitive mechanisms, the tight coupling of the effects of mental processes and autonomic/metabolic reactions should be considered.
AB - Functional neuroimaging studies have shown that cognitive processes increase regional cerebral blood flow in relation with enhanced neuronal activity. However, cognition induces elevation of blood pressure, heart rate and respiratory rate, each of which also affects cerebral circulation. For proper interpretation of functional neuroimaging data, it is necessary to dissociate the effects of systemic and local metabolic reactions on regional cerebral circulation. To elucidate this interaction, we examined the changes in cerebral blood flow velocity, which were caused by voluntary hyperventilation-induced hypocapnia without cognitive effort and hypocapnia evolving during mental arithmetic task. The cerebral blood flow velocity was recorded in the middle cerebral arteries, using transcranial Doppler sonography. Respiratory rate, end-tidal partial pressure of CO2, heart rate and arterial blood pressure were simultaneously monitored. Data were statistically evaluated. Hypocapnia induced by voluntary hyperventilation without cognition decreased the cerebral blood flow velocity. During mental arithmetic, the cerebral blood flow velocity first increased, but the hypocapnia, which was induced by involuntarily hyperventilation related to cognitive effort, reduced it. This implies temporary vasoconstriction of cerebral microvessels, and the increase in cerebral vascular resistance index supports this finding. These results suggest that hypocapnia, which develops during cognition, may decrease blood flow velocity in the middle cerebral arteries, which interferes with the neuronal activity-driven regulation of cerebral circulation. In conclusion, when interpreting the results of functional neuroimaging studies on cognitive mechanisms, the tight coupling of the effects of mental processes and autonomic/metabolic reactions should be considered.
KW - Blood pressure
KW - Heart rate
KW - Hypocapnia
KW - Mental arithmetic
KW - Transcranial Doppler sonography
UR - http://www.scopus.com/inward/record.url?scp=66949167840&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=66949167840&partnerID=8YFLogxK
U2 - 10.1620/tjem.217.147
DO - 10.1620/tjem.217.147
M3 - Article
C2 - 19212108
AN - SCOPUS:66949167840
VL - 217
SP - 147
EP - 154
JO - Tohoku Journal of Experimental Medicine
JF - Tohoku Journal of Experimental Medicine
SN - 0040-8727
IS - 2
ER -