title: Anxiety, pCO2 and cerebral blood flow.
abstract: This study examined the effect of anxiety on cerebral blood flow at different levels of pCO2 in healthy participants (N=29). Three types of breathing were used to manipulate pCO2 in a within-subject threat-of-shock paradigm: spontaneous breathing, CO2-inhalation and hyperventilation resulting in normo-, hyper- and hypocapnia. Transcranial Doppler ultrasonography was used to measure CBF velocity (CBFv) in the right middle cerebral artery, while breathing behavior and end-tidal pCO2 were monitored. During normocapnia, elevated anxiety was clearly associated with increased CBFv. Consistent with the cerebral vasoconstrictive and vasodilating effects of, respectively, hypo- and hypercapnia, we observed a positive linear association between CBFv and pCO2. The slope of this association became steeper with increasing anxiety, indicating that anxiety enhances the sensitivity of CBFv to changes in pCO2. The findings may elucidate conflicting findings in the literature and are relevant for brain imaging relying on regional cerebral blood flow.
authors.affiliation: Research Group on Health Psychology, University of Leuven, Tiensestraat 102, 3000 Leuven, Belgium. omer.vandenbergh@ppw.kuleuven.be
authors.forename: Omer
authors.initials: O
authors.lastname: Van den Bergh
authors.forename: Jonas
authors.initials: J
authors.lastname: Zaman
authors.forename: Johan
authors.initials: J
authors.lastname: Bresseleers
authors.forename: Peter
authors.initials: P
authors.lastname: Verhamme
authors.forename: Ilse
authors.initials: I
authors.lastname: Van Diest
mesh_terms: D000293:Adolescent; D000328:Adult; D001007:Anxiety / Q000097:blood* / Q000378:metabolism / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000097:blood*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003627:Data Interpretation, Statistical; D004558:Electric Stimulation; D005239:Fear / Q000502:physiology; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology / Q000523:psychology; D016857:Hypocapnia / Q000503:physiopathology / Q000523:psychology; D008297:Male; D020768:Middle Cerebral Artery / Q000502:physiology / Q000503:physiopathology; D012044:Regression Analysis; D015656:Respiratory Mechanics; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide
keywords: Anxiety; CBF; CBFv; CO(2); Cerebral blood flow; FetCO(2); MCA; Middle cerebral artery; Shock; TCD; Transcranial Doppler ultrasonography; cerebral blood flow; cerebral blood flow velocity; fractional end-tidal concentration of CO(2); middle cerebral artery; pCO(2); partial arterial CO(2) pressure