Page 113 - 《运动与健康科学》(英文)2024年第2期

TaggedAPTARAFigure
TaggedAPTARAEndHeat exposure on brain activity and cognitive function 235

Fig. 1. Experimental design and task-based fMRI protocols. (A) For EX trial, participants were given ambient temperature drink after their first MRI scan, followed by
a treadmill run until they achieved 39.5˚C. The trial ended with a second MRI scan after the run. PA trial shares the same protocol as EX except participants were
passively heated in a water bath at 41˚C until they achieved 39.5˚C. Exertional hyperthermia with CL shares the same protocol as EX except participantsingested
blended ice instead of ambient temperature (25˚C) drinks. CT excludes any hyperthermia-inducing interventions (exercise/immersion) where participants rested in a
sitting position and ingested ambient temperature drinks. (B) Insulative thermal inner wear to limit heat loss and absorb sweat. (C) Water-perfused thermosuit with
circulating water at 41˚C to restrict heat loss in scanner. (D) External water pump with insulated tubes. (E) Step ergometer (denoted by red box) for the conduct of plan-
tarflexion task in MRI scanner. (F) Motor task-based fMRI scan where participants were asked to perform 10 sets of plantarflexion with rest intervals of 1 min, repeated
for 12 blocks. (G) Cognitive task-based fMRI scan where participants performed the Stroop color-naming task for 1 min followed by 1-min fixation task, repeated for 4
blocks. CL = cooling trial; CT = control trial; EX = exertional hyperthermia trial; fMRI = functional magnetic resonance imaging; MRI = magnetic resonance imaging;
MVC = maximal voluntary contraction; PA = passive hyperthermia trial; VO 2peak = peak oxygen consumption.TaggedAPTARAEnd

41˚C by an external heater. Immersion was terminated TaggedAPTARAEndTaggedAPTARAP(b) Single voxel spectroscopy with weak water suppression;
bandwidth = 2000 Hz, acquisition duration = 1024 ms,
when T re hit 39.5˚C.TaggedAPTARAEnd
repetition time = 1500 ms, echo time = 30 ms, flip
angle = 90˚, 32 acquisitions. The single voxel was
TaggedAPTARAP2.2.3. Cooling trial (CL)TaggedAPTARAEnd
TaggedAPTARAPThe protocol was similar to EX trial except that well-blended centered at primary motor cortex.TaggedAPTARAEnd
ice (1˚C) was given instead of ambient temperature (25˚C) TaggedAPTARAP(c) Pseudo-continuous ASL with multi-slice single-shot echo
water. The mass of ice slurry given was identical to that of planar imaging sequence; 21 slices with 4 mm thickness,
field of view = 256 mm £ 256 mm, matrix size = 64 £ 64,
water provided in other trials.TaggedAPTARAEnd
repetition time = 4000 ms, echo time = 9.2 ms, flip
angle = 90˚, 20 label/control pairs, scanning time = 6 min,
TaggedAPTARAP2.2.4. Control trial (CT)TaggedAPTARAEnd
TaggedAPTARAPThe protocol was similar to PA trial with the exception of label offset = 124 mm and post-label delay = 1500 ms.TaggedAPTARAEnd
warm water immersion. Participants rested in a sitting position TaggedAPTARAP(d) Task (motor)-based functional MRI (fMRI) with BOLD
during the 60-min period (or shorter, depending on prior exer- contrast using a gradient-echo echo planar imaging pulse
sequence; 36 slices with 4-mm slice thickness, repetition
cise/passive heating duration) after the drinking phase.TaggedAPTARAEnd
time = 2000 ms, echo time = 30 ms, field of view = 256
mm £ 256 mm, matrix size = 64 £ 64. During imaging,
TaggedAPTARAH22.3. MRI data acquisitionTaggedAPTARAEnd
the participants were placed in a supine position with the
1
TaggedAPTARAPThe MRI protocols included T1-weighted imaging, H
head immobilized. The right foot was placed on a pedal
magnetic resonance spectroscopy (MRS), arterial spin labeling
ergometer (Trispect module; Ergospect, Innsbruck,
(ASL), and blood oxygenation level-dependent (BOLD) contrast
Austria), where participants performed dorsi- and plantar-
imaging. All scans were recorded using a 3T Magnetom TrioTim
flexion (Fig. 1E). Each task lasted for 20 s, with each
(Siemens Medical Systems, Erlangen, Germany) and a 32-channel
flexion performed at 2-s intervals with verbal instructions,
head coil. The image protocols were:
and was followed by a rest period of 40 s. This constitutes
1 task block (1 min), and the process was repeated for 12
TaggedAPTARAEndTaggedAPTARAP(a) High-resolution isotropic T1-weighted magnetization blocks (12 min). The pedal resistance was pseudo-
prepared rapid gradient recalled echo (MPRAGE); 176 randomly assigned at 20%, 40%, 60%, 80% of their pre-
slices, 1 mm thickness, sagittal acquisition, field of
determined maximal voluntary contraction (Fig. 1F).TaggedAPTARAEnd
view = 256 mm £ 256 mm, matrix size = 256 £ 256, TaggedAPTARAP(e) Task (cognitive)-based fMRI with BOLD contrast using
repetition time = 1950 ms, echo time = 3.06 ms, inversion a gradient-echo echo planar imaging pulse sequence;
time = 900 ms, flip angle = 9˚.TaggedAPTARAEnd 36 slices with 4 mm slice thickness, repetition