Timo Klein

Directional sensitivity analysis of the cerebral pressure-flow relationship during normothermia and moderate hyperthermia | Journal of Applied Physiology | American Physiological Society Dynamic cerebral autoregulation (dCA) reacts differently when mean arterial pressure (MAP) increases versus decreases (i.e. directional sensitivity). While heat stress alters dCA, its influence on directional sensitivity remains unclear. This analysis investigated the impact of moderate hyperthermia on the directional sensitivity in the cerebral pressure‐flow relationship. Ten healthy participants (7 males; age: 37 ± 12 yrs.; body mass: 75 ± 9 kg) underwent 6 min of oscillatory lower body negative pressure (OLBNP) to induce large MAP fluctuations, at 0.03 and 0.10 Hz under normothermic and moderately hyperthermic conditions (+1.0°C increase in core temperature) induced via a water‐perfused suit. We calculated changes in middle cerebral artery mean blood velocity (MCAv) per alterations to MAP to compute absolute and relative ratios adjusted for time intervals during each OLBNP‐induced MAP increases (ΔMCAvT/ΔMAPTINC; %MCAvT/%MAPTINC) and decreases (ΔMCAvT/ΔMAPTDEC; %MCAvT/%MAPTDEC). Thereafter, we compared average absolute and relative ratios. There was no main effect of MAP direction on ΔMCAvT/ΔMAPT or %MCAvT/%MAPT during either 0.03 Hz (P=0.291, P=0.281) or 0.10 Hz (P=0.295, P=0.178) OLBNP. Regardless of MAP direction, ΔMCAvT/ΔMAPTINC (0.65 ± 0.17 vs 0.84 ± 0.22 cm. s−1/mmHg), ΔMCAvT/ΔMAPTDEC (0.70 ± 0.15 vs 0.85 ± 0.18 cm. s−1/mmHg) (thermal state: P=0.009), %MCAvT/%MAPTINC (0.92 ± 0.22 vs 1.33 ± 0.60), and %MCAvT/%MAPTDEC (1.01 ± 0.27 vs 1.30 ± 0.51) (thermal state: P=0.001) were lower in hyperthermia at 0.03 Hz OLBNP. Regardless of thermal states, these findings suggest an absence of dCA directional sensitivity. Reduced directional sensitivity metrics during hyperthermia may indicate more efficient dCA at very low frequency.

Directional sensitivity analysis of the cerebral pressure-flow relationship during normothermia and moderate hyperthermia

journals.physiology.org/doi/abs/10.1...

Great start to 2025! After the final submission of his MSc thesis a few weeks ago, grad student and resident in anesthesiology Edouard Marques has his manuscript accepted for publication in @expphysiol.bsky.social !

Cerebrovascular Control in Health and Disease: From Modeling to Translational Research <p>The <em>Journal of Applied Physiology</em> publishes original papers that deal with diverse areas of research in applied physiology, especially those papers emphasizing adaptive and integrative mec...

Reminder to all cerebrovascular physiologists!

Call for Papers in J Appl Physiol!

Cerebrovascular Control in Health and Disease: From Modeling to Translational Research

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The relationships between age, sex, and exercise intensity on cerebral artery hemodynamics during isometric handgrip exercise | American Journal of Physiology-Regulatory, Integrative and Comparative P... Age and sex may alter the cerebral blood flow (CBF) responses to acute isometric exercise, via associated elevations in mean arterial pressure (MAP) and sympathetic activation. Our aim was to determin...

The relationships between age, sex, and exercise intensity on cerebral artery hemodynamics during isometric handgrip exercise

journals.physiology.org/doi/full/10....

I am very excited to share our new paper in #JCBFM (journals.sagepub.com/doi/10.1177/...)! We show that targeting Na,K-ATPase-dependent #Src kinase activation can prevent cerebral hypoperfusion and ⬆️ (video) #neurovascular coupling in a 🐭model of familial hemiplegic #migraine.

Here is a summary 🧵

Consequences of adolescent sport-related concussion: exploring long-term cardiorespiratory fitness and adiposity Little is known regarding long-term consequences (≥5 years) of sport-related concussion (SRC) sustained during adolescence. Adolescent SRC has been linked to athlete considerations of sport partici...

New collaborative work with the University of Calgary crew led by Joseph Carere and Benjamin Leggett !

Consequences of adolescent sport-related concussion: exploring long-term cardiorespiratory fitness and adiposity

www.tandfonline.com/doi/10.1080/...

If you work in the field of cerebrovascular regulation (physiology, clinical, and/or measurement/modeling), check out the Cerebrovascular Research Network (CARNet), and consider becoming a member!

www.car-net.org

Cerebrovascular Control in Health and Disease: From Modeling to Translational Research <p>The <em>Journal of Applied Physiology</em> publishes original papers that deal with diverse areas of research in applied physiology, especially those papers emphasizing adaptive and integrative mec...

If you work in the field of cerebrovascular physiology, consider submitting your work to our special call for papers #JAPPL: Cerebrovascular Control in Health and Disease: From Modeling to Translational Research

journals.physiology.org/jappl/cerebr...