Muscle metaboreflex activation by static exercise dilates pupil in humans

Hayashi, Naoyuki; Someya, Nami

doi:10.1007/s00421-010-1716-z

Cited by 12 publications

(16 citation statements)

References 19 publications

(36 reference statements)

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“…We also assessed the data using the handgrip-specific top-20 pupil diameter value method [9]. In a repeated measures ANOVA, there were no significant differences in the top-20 pupil response to the handgrip and the control block (F (1, 48) = .33, p > 0.1).…”

Section: Resultsmentioning

confidence: 99%

“…We selected this measure for analysis because pupil dilation is considered a reliable measure of sympathetic arousal [33, 34]. Also, a recent study with isometric handgrip showed pupil diameter increased in response to a 2-min isometric handgrip task [9]. Fixation events and pupil dilation data for each participant were exported using the eye-tracking analysis software program BeGaze 2 (SensoMotoric Instruments).…”

Section: Methodsmentioning

confidence: 99%

“…Fixation events and pupil dilation data for each participant were exported using the eye-tracking analysis software program BeGaze 2 (SensoMotoric Instruments). To calculate the pupil diameter change in response to the handgrip and control tasks, we examined pupil diameter values across the entire task and we adopted methods from Hayashi and Someya [9]. These methods were implemented to assess the change in pupil diameter across the task duration from baseline.…”

Section: Methodsmentioning

confidence: 99%

“…For a handgrip-specific pupil analysis, we also assessed the pupil data using established methods adopted from Hayashi and Someya [9]. We determined the 20 fixations with the greatest pupil diameter during each 1-min interval in the 3-min task and during each 18-s interval in the 18-s task to obtain the top-20 pupil diameter values.…”

Section: Methodsmentioning

confidence: 99%

“…The only study to use pupil dilation as an index of arousal used a paradigm with 2-min of isometric handgrip at 30% of maximal exertion; results showed increased pupil dilation to the handgrip task [9]. …”

Section: Introductionmentioning

confidence: 99%

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Comparison of two isometric handgrip protocols on sympathetic arousal in women

Nielsen

Mather

2015

Physiology & Behavior

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Isometric handgrip is commonly used in stress research because the task reliably increases sympathetic arousal. Various handgrip protocols have been used; they vary in handgrip strength, duration of grip, and the number of cycles of handgrip and rest. However, most protocols require the calibration of a maximum voluntary contraction (MVC) prior to the handgrip task, which is not always convenient (i.e., in a functional magnetic resonance imaging study). Here, we wanted to test whether two handgrip protocols with different strength, duration and cycle protocols would reliably elicit sympathetic arousal in the absence of calibrating an MVC. Sixty-two healthy naturally cycling women and women on hormonal contraception participated in one of the two isometric handgrip protocols using a hand therapy ball of medium resistance. Women completed one of the following handgrip protocols: 1) 30% of a perceived maximum voluntary contraction for 3 minutes or 2) 3 cycles of maximum voluntary contraction for 18 seconds with one minute rest in between. All handgrip blocks were counterbalanced with a control condition. Sympathetic arousal was measured throughout the session via pupil diameter changes and salivary alpha-amylase. Results indicate that in the absence of calibrating an MVC, the handgrip tasks elicited different changes in sympathetic arousal. Pupil dilation responses increased significantly in the handgrip versus control blocks only in participants in the 18-s protocol. Additionally, more participants exhibited a salivary alpha-amylase response to the handgrip block in the 18-s condition compared to the 3-min condition. Thus, these results suggest that neuroimaging and behavioral studies with isometric handgrip should be able to successfully induce sympathetic nervous activity with the 18-s paradigm, regardless of the handgrip device and the ability to calibrate an MVC.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparison of two isometric handgrip protocols on sympathetic arousal in women

Nielsen

Mather

2015

Physiology & Behavior

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Autoregulation in the ocular and cerebral arteries during the cold pressor test and handgrip exercise

2011

Self Cite

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The aim of this study was to determine whether autoregulation exerts similar effects in the ocular and cerebral vessels, which are both branches of the internal carotid artery. Ocular blood flow velocities, cerebral blood flow velocity and blood pressure were measured in 11 subjects during a 2-min resting period, static handgrip exercise (HG) and a cold pressor test (CPT). Blood velocity data for the superior and inferior temporal retinal arterioles (STRA and ITRA, respectively) and the retinal and choroidal vasculature (RCV) were obtained for 4 s during the measurement using laser speckle flowmetry. Mean blood flow velocity in the middle cerebral artery (MCAVmean) was measured by transcranial Doppler ultrasound. The conductance index (CI) of each vessel was calculated by dividing blood flow by mean arterial pressure. Blood flow velocity in the RCV increased by 19 ± 9% from resting baseline level during the CPT (P < 0.05), while blood flow in the STRA, ITRA and MCAVmean did not. The CI of the MCA decreased. The RCV blood flow velocity, ITRA blood flow and MCAVmean increased by 8 ± 1, 9 ± 3 and 11 ± 4%, respectively, during the HG (P < 0.05). Conversely, STRA blood flow remained unchanged. The HG did not significantly change the CI in any of the vessels measured. These findings suggest that cerebral blood flow velocity was maintained during the CPT, but autoregulation does not work well in the RCV during the CPT and HG.

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Sympathetic arousal increases a negative memory bias in young women with low sex hormone levels

Nielsen

Barber

Chai

et al. 2015

Psychoneuroendocrinology

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Emotionally arousing events are typically better attended to and remembered than neutral ones. Current theories propose that arousal-induced increases in norepinephrine during encoding bias attention and memory in favor of affectively salient stimuli. Here, we tested this hypothesis by manipulating levels of physiological arousal prior to encoding and examining how it influenced memory for emotionally salient images, particularly those that are negative rather than positive in valence. We also tested whether sex steroid hormones interact with noradrenergic activity to influence these emotional memory biases in women. Healthy naturally cycling women and women on hormonal contraception completed one of the following physiological arousal manipulations prior to viewing a series of negative, positive and neutral images: 1) Immediate handgrip arousal – isometric handgrip immediately prior to encoding, 2) Residual handgrip arousal – isometric handgrip 15 min prior to encoding, or 3) No handgrip. Sympathetic arousal was measured throughout the session via pupil diameter changes. Levels of 17β-estradiol and progesterone were measured via salivary samples. Memory performance was assessed approximately 10 minutes after encoding using a surprise free recall test. The results indicated that handgrip successfully increased sympathetic arousal compared to the control task. Under immediate handgrip arousal, women showed enhanced memory for negative images over positive images; this pattern was not observed in women assigned to the residual and no-handgrip arousal conditions. Additionally, under immediate handgrip arousal, both high estradiol and progesterone levels attenuated the memory bias for negative over positive images. Follow-up hierarchical linear models revealed consistent effects when accounting for trial-by-trial variability in normative International Affective Picture System valence and arousal ratings. These findings suggest that heightened sympathetic arousal interacts with estradiol and progesterone levels during encoding to increase the mnemonic advantage of negative over positive emotional material.

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Muscle metaboreflex activation by static exercise dilates pupil in humans

Cited by 12 publications

References 19 publications

Comparison of two isometric handgrip protocols on sympathetic arousal in women

Comparison of two isometric handgrip protocols on sympathetic arousal in women

Autoregulation in the ocular and cerebral arteries during the cold pressor test and handgrip exercise

Sympathetic arousal increases a negative memory bias in young women with low sex hormone levels

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