Jeff Dyche | James Madison University (original) (raw)
Papers by Jeff Dyche
Sleep, Apr 1, 2018
Introduction: While loss of sleep during pregnancy adversely affects brain development, the mecha... more Introduction: While loss of sleep during pregnancy adversely affects brain development, the mechanisms underlying the lasting physiological and behavioral consequences in the offspring remain unknown. The present study was designed to investigate the hypothesis that sleep deprivation (SD) during pregnancy impacts tryptophan metabolism via the kynurenine pathway in the in utero environment. Elevations in kynurenine pathway metabolism, specifically kynurenic acid (KYNA), an endogenous astrocyte-derived antagonist of α7 nicotinic acetylcholine (α7nACh) and NMDA receptors, in utero have been demonstrated to induce long-lasting negative behavioral consequences relevant to the study of psychiatric disorders including schizophrenia (reviewed in Notarangelo and Pocivavsek, Neuropharm. 2017). Methods: Pregnant Wistar rat dams were sleep deprived by gentle handling for 5 h from zeitgeber time (ZT) 0 to ZT 5. Experimental cohorts included: A) one session of SD on embryonic (ED) 18 or B) three sessions of SD on ED 16 to ED 18. Maternal (plasma, brain) and fetal (placenta, plasma, brain) tissues were collected immediately after the last session of SD or after 24 h of recovery from SD. Respective controls were euthanized at ZT 5 on ED 18 and ED 19. Results: Maternal plasma tryptophan and kynurenine, and fetal brain KYNA, were significantly elevated only after one session of SD on ED 18. Importantly, plasma corticosterone, a measure of the endocrine stress response, was significantly elevated in maternal plasma after one day of SD, and this measure, as well as maternal tryptophan, correlated significantly with fetal brain KYNA. Conclusion: Collectively, our results demonstrate that sleep loss during pregnancy can adversely impact kynurenine pathway metabolism and impact fetal brain KYNA levels. We introduce KYNA as a novel molecular target influenced by sleep loss during pregnancy. Future experiments are designed to unravel the contribution of kynurenine pathway changes during maternal sleep loss on long-lasting biochemical and behavioral outcomes in developing offspring. Support (If Any): 1R01 NS102209-01.
This chapter will outline the biological machinery currently known to underpin the stages of cons... more This chapter will outline the biological machinery currently known to underpin the stages of consciousness and the rhythms that modulate them. We will briefly outline the basic functions of our central nervous system and how most researchers divide and categorize the major workings of our brain with an emphasis on the basic behaviors of sleep and alertness and how these two entities are not categorical. During wakefulness, we are kept in an alert state by the workings of some of the most primitive divisions of our brain. However, there are times when a person might be awake but their descriptions of their state varies as a function of what time of day it is and how long they have been awake. Therefore, wake and sleep states are more nuanced; the neural explanations of this will be discussed in detail.
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Applied Neuropsychology: Adult, Aug 11, 2016
The BrainScope Ahead 300 is designed for use by health care professionals to aid in the assessmen... more The BrainScope Ahead 300 is designed for use by health care professionals to aid in the assessment of patients suspected of a mild traumatic brain injury. The purpose of the current study was to establish normative data for the cognitive test component of the Ahead 300 system and to evaluate the role of demographic factors on test performance. Healthy, community-dwelling adults between the ages of 18 and 80 recruited from five geographically distributed sites were administered Android versions of the ANAM Matching to Sample and Procedural Reaction Time tests that comprise the cognitive test component of the Ahead 300 system by trained personnel. Scores were correlated with age, education, and race. Age accounted for the majority of the variance in test scores with additional significant, but minor, contributions of education and race. Gender did not account for a significant proportion of the variance for either test. Based on these results, the normative data for 551 individuals are presented stratified by age. These are the first available normative data for these tests when administered using the Ahead 300 system and will assist health care professionals in determining the degree to which scores on the cognitive tests reflect impaired performance.
Emerging Health Threats Journal, 2012
Background: Studies investigating the effect of power frequency (50Á60 Hz) electromagnetic fields... more Background: Studies investigating the effect of power frequency (50Á60 Hz) electromagnetic fields (EMF) on melatonin synthesis in rats have been inconsistent with several showing suppression of melatonin synthesis, others showing no effect and a few actually demonstrating small increases. Scant research has focused on the ensuing sleep patterns of EMF exposed rats. The present study was designed to examine the effects of extremely low power frequency electromagnetic fields (EMF) on the production of melatonin and the subsequent sleep structure in rats. Methods: Eighteen male Sprague-Dawley rats were exposed to a 1000 milligauss (mG) magnetic field for 1 month. Urine was collected for the final 3 days of the exposure period for analysis of 6-sulphatoxymelatonin, the major catabolic product of melatonin found in urine. Subsequent sleep was analyzed over a 24-hour period. Results: Melatonin production was mildly increased in exposed animals. Although there were no statistically significant changes in sleep structure, exposed animals showed slight decreases in REM (rapid eye movement) sleep as compared to sham (non-exposed) animals. Conclusions: Power frequency magnetic fields induced a marginally statistically significant increase in melatonin levels in exposed rats compared to control. Subsequent sleep analysis indicated little effect on the sleep architecture of rats, at least not within the first day after 1 month's continuous exposure. Varying results in the literature are discussed and future research suggested.
Sleep, Apr 1, 2018
custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for... more custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for each participant. Participants also completed a number of cognitive tasks, within three months of their overnight recordings, of which we focused on a subset of memory tasks from the WebCNP battery (webcnp.med.upenn.edu/battery). Results: Older age was associated with greater spindle density (β=0.24), lower sigma power (β=-0.39), smaller spindle amplitude (β=-0.43) and shorter spindle duration (β=-0.26). No significant differences in spindle characteristics between sexes were identified. Greater spindle density was associated with better delayed performance on the Short Visual Object Learning Task (i.e. number of shapes remembered following an ~25-minute delay after the initial presentation and recall of the shapes) (β=0.26). Spindle characteristics were not associated with general cognitive abilities. Conclusion: Moderate age-related differences in spindle characteristics were identified in this sample of adolescents. We also identified an association between spindle density and performance on an episodic, visual learning task, despite the fact that cognitive testing did not necessarily occur in immediate proximity to the sleep EEG recording. This suggests that the relationship between sleep spindles and cognition may reflect more than memory consolidation. For example, spindle density may be a marker of an individual's learning capacity or may reflect the maturity of certain brain networks which support learning ability. Support (If Any): AA021690 (DBC) and AA021696 (IMC+FCB).
Sleep, May 25, 2022
agreement based on whether a test intervention produced similar effects on vigilance across tests... more agreement based on whether a test intervention produced similar effects on vigilance across tests. Results: Of the 13 studies that included both PVT and MWT of studies, a high level of agreement (based on the presence and direction significant effect on vigilance) between test outcomes was evident in 8 (61.5%) of the studies. In contrast, a considerably lower percentage of studies in which both the PVT and MSLT were performed (6 of 17 studies; 35.3%) had high agreement between test outcomes. It was also found that the MSLT was more sensitive to interventions (e.g., caffeine, sleep loss, and cognitive workload) than the PVT in the majority of studies in which there was low agreement (5 of 6 studies; 83.3%). Conclusion: There is generally more agreement between PVT and MWT measures than between PVT and MSLT measures in studies involving sleep loss. This is most likely because the PVT and MWT both require application of effort to resist sleepiness, whereas the MSLT involves the withdrawal of resistance to sleepiness. This suggests that the PVT is potentially more useful in operational environments (where ability to sustain performance is the primary concern) than in clinical settings (where the focus is on determining the severity of sleepiness). Support (If Any
Sleep, Jun 6, 2022
Sleep loss has been shown to alter risk preference during decision-making. However, research in t... more Sleep loss has been shown to alter risk preference during decision-making. However, research in this area has largely focussed on the effects of total sleep deprivation (TSD), while evidence on the effects of sleep restriction (SR) or the potentially moderating role of sex on risk preference remains scarce and unclear. The present study investigated risky decision-making in 47 healthy young adults who were assigned to either of two counterbalanced protocols: well-rested (WR) and TSD, or WR and SR. Participants were assessed on the Lottery Choice Task (LCT), which requires a series of choices between two risky gambles with varying risk levels. Analyses on the pooled dataset indicated across all sleep conditions, participants were generally more risk-seeking when trying to minimise financial loss (LOSSES) than while trying to maximise financial gain (GAINS). On GAINS trials, female participants were more risk-averse during TSD and SR, whereas male participants remained unchanged. On LOSSES trials, female participants remained unchanged during TSD and SR, whereas male participants became more risk-seeking during TSD. Our findings suggest the relationship between sleep loss and risk preference is moderated by sex, whereby changes in risk preference after TSD or SR differ in men and women depending on whether the decision is framed in terms of gains or losses.
Neuropharmacology, 1989
The present study examined the analgesic effects of the serotonin 5-HT3 receptor antagonists ICS-... more The present study examined the analgesic effects of the serotonin 5-HT3 receptor antagonists ICS-205-930, MDL-7222 and GR-38032F in mice using acute thermal, mechanical and chemical pain tests. Subcutaneous administration (1-10 mg/kg) of these agents did not produce analgesia in either the thermal or mechanical pain tests. However, ICS-205-930, MDL-72222 and GR-38032F all produced dose-dependent analgesia in the chemical pain test, that was not altered by systemic naloxone administration (1 mg/kg, s.c.). Intracerebroventricular administration of these drugs (0.1-10 micrograms) was ineffective in producing analgesia in acute thermal, mechanical and chemical pain tests. These results suggest that peripheral 5-HT3 receptors play a role in chemical, but not thermal or mechanical nociceptive mechanisms.
Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc
With a desire to increase health, cognitive performance effectiveness, and quality of life for su... more With a desire to increase health, cognitive performance effectiveness, and quality of life for submarine watch-standers underway, we performed an evaluation comparing an alternative, compressed-work (ALT) schedule, designed to enhance circadian rhythm entrainment and sleep hygiene, to the contemporary submarine (SUB) forward rotating schedule, aboard the ballistic-missile submarine, USS Henry M. Jackson (SSBN-730 Gold). We assessed a compressed close-6 watch-schedule ("ALT") relative to the existing backward rotating 6-hr on, 12-hr off 18-hr watch schedule ("SUB") employed underway aboard submarines. We monitored 40 subjects' sleep, and temperature and salivary cortisol from 10 of the 40 for approximately two weeks on each respective schedule underway. The cortisol cosinor mesors (midline estimating statistic of rhythm), and amplitudes did not differ significantly between conditions. The temperature cosinor mesors, and the cosinor amplitude were not significa...
Sleep
Introduction Alcohol is one of the most common psychoactive drugs that has depressant effects on ... more Introduction Alcohol is one of the most common psychoactive drugs that has depressant effects on the central nervous system. The vast majority of research on alcohol and sleep indicates chronic alcohol consumption has a detrimental impact on sleep architecture and homeostasis. However, less research has explored the effects of sleep deprivation on alcohol consumption; that is, the relationship in the opposite direction. Previous animal studies have explored a potential bi-directional relationship between sleep and alcohol with promising results. However, there was concern that the potential relationship may be a result of stress as a by-product of the sleep deprivation method. The present study examines the effect of sleep deprivation on voluntary alcohol consumption using two sleep deprivation methods in the rat, forced exercise wheels and the automated sleep deprivation system. Methods Twelve male Sprague-Dawley rats had ad libitum access to a 7% alcohol solution and water. Alcoho...
Sleep
Introduction Depression, sleep disturbances, and cognitive deficits often co-occur. Compared to n... more Introduction Depression, sleep disturbances, and cognitive deficits often co-occur. Compared to non-medicated controls, people using antidepressant medications (particularly serotonin agonists) often have improved sleep including increased slow wave sleep, quality and continuity. Improvements to cognition after antidepressant treatments are also common including benefits to reaction time, inhibition, and memory. Importantly, circadian deficits, including sleep onset latency, fragmentation, and phase shifts are common in patients with depression, yet the effect of antidepressant medication on circadian indicators is unclear. The current project examined sleep, circadian entrainment, and cognition in college students who were diagnosed with depression and using serotonin agonists and in those without depressive symptoms. Methods Participants completed cognitive tasks that assessed reaction time, memory, attention, inhibition, and logical reasoning via the Automated Neuropsychological ...
Sleep
Sleep loss has been shown to alter risk preference during decision-making. However, research in t... more Sleep loss has been shown to alter risk preference during decision-making. However, research in this area has largely focussed on the effects of total sleep deprivation (TSD), while evidence on the effects of sleep restriction (SR) or the potentially moderating role of sex on risk preference remains scarce and unclear. The present study investigated risky decision-making in 47 healthy young adults who were assigned to either of two counterbalanced protocols: well-rested (WR) and TSD, or WR and SR. Participants were assessed on the Lottery Choice Task (LCT), which requires a series of choices between two risky gambles with varying risk levels. Analyses on the pooled dataset indicated across all sleep conditions, participants were generally more risk-seeking when trying to minimise financial loss (LOSSES) than while trying to maximise financial gain (GAINS). On GAINS trials, female participants were more risk-averse during TSD and SR, whereas male participants remained unchanged. On L...
electromagnetic fields on melatonin and sleep in the rat
Sleep, Apr 1, 2018
a MEGA-PRESS sequence within three a priori voxels of interest: the ventromedial prefrontal corte... more a MEGA-PRESS sequence within three a priori voxels of interest: the ventromedial prefrontal cortex (vmPFC), dorsolateral prefrontal cortex (dlPFC) and parietal-occipital region. Spectra were collected for a variety of brain metabolites, including gamma-Aminobutyric acid (GABA). MRS data were processed using LCModel software and expressed as a ratio to creatine. A 10-min psychomotor vigilance test (PVT) was administered hourly throughout SD. The first three PVT bouts served as a measure of baseline performance. Individual mean response speed on the PVT was normalized to baseline and used as an index of subject-specific resilience to SD. Due to technical complications, dlPFC MRS data was unavailable for n=9 subjects and parietal-occipital MRS data was unavailable for n=3 subjects. Results: A Pearson's partial correlation, controlling for gender, showed that baseline levels of GABA in the vmPFC were significantly correlated with resilience index (r=0.38, p=0.015), such that higher levels of GABA were associated with greater resilience. GABA levels in the dlPFC (r=0.17, p=0.358) and parietal-occipital region (r=0.15, p=0.389) were not significantly correlated with resilience. Conclusion: Subjects with higher versus lower GABA levels in the vmPFC were more resilient to PVT impairment during SD. These findings suggest that inhibitory neurotransmitters, such as GABA, are potential predictors of resilience to SD-induced performance impairment. Elevated levels of GABA in the vmPFC may reduce sensitivity to distractions, allowing for improved sustained attention and optimal performance. Support (If Any): 0234
Sleep, Apr 1, 2018
custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for... more custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for each participant. Participants also completed a number of cognitive tasks, within three months of their overnight recordings, of which we focused on a subset of memory tasks from the WebCNP battery (webcnp.med.upenn.edu/battery). Results: Older age was associated with greater spindle density (β=0.24), lower sigma power (β=-0.39), smaller spindle amplitude (β=-0.43) and shorter spindle duration (β=-0.26). No significant differences in spindle characteristics between sexes were identified. Greater spindle density was associated with better delayed performance on the Short Visual Object Learning Task (i.e. number of shapes remembered following an ~25-minute delay after the initial presentation and recall of the shapes) (β=0.26). Spindle characteristics were not associated with general cognitive abilities. Conclusion: Moderate age-related differences in spindle characteristics were identified in this sample of adolescents. We also identified an association between spindle density and performance on an episodic, visual learning task, despite the fact that cognitive testing did not necessarily occur in immediate proximity to the sleep EEG recording. This suggests that the relationship between sleep spindles and cognition may reflect more than memory consolidation. For example, spindle density may be a marker of an individual's learning capacity or may reflect the maturity of certain brain networks which support learning ability. Support (If Any): AA021690 (DBC) and AA021696 (IMC+FCB).
Sleep, Apr 1, 2018
Introduction: While loss of sleep during pregnancy adversely affects brain development, the mecha... more Introduction: While loss of sleep during pregnancy adversely affects brain development, the mechanisms underlying the lasting physiological and behavioral consequences in the offspring remain unknown. The present study was designed to investigate the hypothesis that sleep deprivation (SD) during pregnancy impacts tryptophan metabolism via the kynurenine pathway in the in utero environment. Elevations in kynurenine pathway metabolism, specifically kynurenic acid (KYNA), an endogenous astrocyte-derived antagonist of α7 nicotinic acetylcholine (α7nACh) and NMDA receptors, in utero have been demonstrated to induce long-lasting negative behavioral consequences relevant to the study of psychiatric disorders including schizophrenia (reviewed in Notarangelo and Pocivavsek, Neuropharm. 2017). Methods: Pregnant Wistar rat dams were sleep deprived by gentle handling for 5 h from zeitgeber time (ZT) 0 to ZT 5. Experimental cohorts included: A) one session of SD on embryonic (ED) 18 or B) three sessions of SD on ED 16 to ED 18. Maternal (plasma, brain) and fetal (placenta, plasma, brain) tissues were collected immediately after the last session of SD or after 24 h of recovery from SD. Respective controls were euthanized at ZT 5 on ED 18 and ED 19. Results: Maternal plasma tryptophan and kynurenine, and fetal brain KYNA, were significantly elevated only after one session of SD on ED 18. Importantly, plasma corticosterone, a measure of the endocrine stress response, was significantly elevated in maternal plasma after one day of SD, and this measure, as well as maternal tryptophan, correlated significantly with fetal brain KYNA. Conclusion: Collectively, our results demonstrate that sleep loss during pregnancy can adversely impact kynurenine pathway metabolism and impact fetal brain KYNA levels. We introduce KYNA as a novel molecular target influenced by sleep loss during pregnancy. Future experiments are designed to unravel the contribution of kynurenine pathway changes during maternal sleep loss on long-lasting biochemical and behavioral outcomes in developing offspring. Support (If Any): 1R01 NS102209-01.
This chapter will outline the biological machinery currently known to underpin the stages of cons... more This chapter will outline the biological machinery currently known to underpin the stages of consciousness and the rhythms that modulate them. We will briefly outline the basic functions of our central nervous system and how most researchers divide and categorize the major workings of our brain with an emphasis on the basic behaviors of sleep and alertness and how these two entities are not categorical. During wakefulness, we are kept in an alert state by the workings of some of the most primitive divisions of our brain. However, there are times when a person might be awake but their descriptions of their state varies as a function of what time of day it is and how long they have been awake. Therefore, wake and sleep states are more nuanced; the neural explanations of this will be discussed in detail.
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Applied Neuropsychology: Adult, Aug 11, 2016
The BrainScope Ahead 300 is designed for use by health care professionals to aid in the assessmen... more The BrainScope Ahead 300 is designed for use by health care professionals to aid in the assessment of patients suspected of a mild traumatic brain injury. The purpose of the current study was to establish normative data for the cognitive test component of the Ahead 300 system and to evaluate the role of demographic factors on test performance. Healthy, community-dwelling adults between the ages of 18 and 80 recruited from five geographically distributed sites were administered Android versions of the ANAM Matching to Sample and Procedural Reaction Time tests that comprise the cognitive test component of the Ahead 300 system by trained personnel. Scores were correlated with age, education, and race. Age accounted for the majority of the variance in test scores with additional significant, but minor, contributions of education and race. Gender did not account for a significant proportion of the variance for either test. Based on these results, the normative data for 551 individuals are presented stratified by age. These are the first available normative data for these tests when administered using the Ahead 300 system and will assist health care professionals in determining the degree to which scores on the cognitive tests reflect impaired performance.
Emerging Health Threats Journal, 2012
Background: Studies investigating the effect of power frequency (50Á60 Hz) electromagnetic fields... more Background: Studies investigating the effect of power frequency (50Á60 Hz) electromagnetic fields (EMF) on melatonin synthesis in rats have been inconsistent with several showing suppression of melatonin synthesis, others showing no effect and a few actually demonstrating small increases. Scant research has focused on the ensuing sleep patterns of EMF exposed rats. The present study was designed to examine the effects of extremely low power frequency electromagnetic fields (EMF) on the production of melatonin and the subsequent sleep structure in rats. Methods: Eighteen male Sprague-Dawley rats were exposed to a 1000 milligauss (mG) magnetic field for 1 month. Urine was collected for the final 3 days of the exposure period for analysis of 6-sulphatoxymelatonin, the major catabolic product of melatonin found in urine. Subsequent sleep was analyzed over a 24-hour period. Results: Melatonin production was mildly increased in exposed animals. Although there were no statistically significant changes in sleep structure, exposed animals showed slight decreases in REM (rapid eye movement) sleep as compared to sham (non-exposed) animals. Conclusions: Power frequency magnetic fields induced a marginally statistically significant increase in melatonin levels in exposed rats compared to control. Subsequent sleep analysis indicated little effect on the sleep architecture of rats, at least not within the first day after 1 month's continuous exposure. Varying results in the literature are discussed and future research suggested.
Sleep, Apr 1, 2018
custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for... more custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for each participant. Participants also completed a number of cognitive tasks, within three months of their overnight recordings, of which we focused on a subset of memory tasks from the WebCNP battery (webcnp.med.upenn.edu/battery). Results: Older age was associated with greater spindle density (β=0.24), lower sigma power (β=-0.39), smaller spindle amplitude (β=-0.43) and shorter spindle duration (β=-0.26). No significant differences in spindle characteristics between sexes were identified. Greater spindle density was associated with better delayed performance on the Short Visual Object Learning Task (i.e. number of shapes remembered following an ~25-minute delay after the initial presentation and recall of the shapes) (β=0.26). Spindle characteristics were not associated with general cognitive abilities. Conclusion: Moderate age-related differences in spindle characteristics were identified in this sample of adolescents. We also identified an association between spindle density and performance on an episodic, visual learning task, despite the fact that cognitive testing did not necessarily occur in immediate proximity to the sleep EEG recording. This suggests that the relationship between sleep spindles and cognition may reflect more than memory consolidation. For example, spindle density may be a marker of an individual's learning capacity or may reflect the maturity of certain brain networks which support learning ability. Support (If Any): AA021690 (DBC) and AA021696 (IMC+FCB).
Sleep, May 25, 2022
agreement based on whether a test intervention produced similar effects on vigilance across tests... more agreement based on whether a test intervention produced similar effects on vigilance across tests. Results: Of the 13 studies that included both PVT and MWT of studies, a high level of agreement (based on the presence and direction significant effect on vigilance) between test outcomes was evident in 8 (61.5%) of the studies. In contrast, a considerably lower percentage of studies in which both the PVT and MSLT were performed (6 of 17 studies; 35.3%) had high agreement between test outcomes. It was also found that the MSLT was more sensitive to interventions (e.g., caffeine, sleep loss, and cognitive workload) than the PVT in the majority of studies in which there was low agreement (5 of 6 studies; 83.3%). Conclusion: There is generally more agreement between PVT and MWT measures than between PVT and MSLT measures in studies involving sleep loss. This is most likely because the PVT and MWT both require application of effort to resist sleepiness, whereas the MSLT involves the withdrawal of resistance to sleepiness. This suggests that the PVT is potentially more useful in operational environments (where ability to sustain performance is the primary concern) than in clinical settings (where the focus is on determining the severity of sleepiness). Support (If Any
Sleep, Jun 6, 2022
Sleep loss has been shown to alter risk preference during decision-making. However, research in t... more Sleep loss has been shown to alter risk preference during decision-making. However, research in this area has largely focussed on the effects of total sleep deprivation (TSD), while evidence on the effects of sleep restriction (SR) or the potentially moderating role of sex on risk preference remains scarce and unclear. The present study investigated risky decision-making in 47 healthy young adults who were assigned to either of two counterbalanced protocols: well-rested (WR) and TSD, or WR and SR. Participants were assessed on the Lottery Choice Task (LCT), which requires a series of choices between two risky gambles with varying risk levels. Analyses on the pooled dataset indicated across all sleep conditions, participants were generally more risk-seeking when trying to minimise financial loss (LOSSES) than while trying to maximise financial gain (GAINS). On GAINS trials, female participants were more risk-averse during TSD and SR, whereas male participants remained unchanged. On LOSSES trials, female participants remained unchanged during TSD and SR, whereas male participants became more risk-seeking during TSD. Our findings suggest the relationship between sleep loss and risk preference is moderated by sex, whereby changes in risk preference after TSD or SR differ in men and women depending on whether the decision is framed in terms of gains or losses.
Neuropharmacology, 1989
The present study examined the analgesic effects of the serotonin 5-HT3 receptor antagonists ICS-... more The present study examined the analgesic effects of the serotonin 5-HT3 receptor antagonists ICS-205-930, MDL-7222 and GR-38032F in mice using acute thermal, mechanical and chemical pain tests. Subcutaneous administration (1-10 mg/kg) of these agents did not produce analgesia in either the thermal or mechanical pain tests. However, ICS-205-930, MDL-72222 and GR-38032F all produced dose-dependent analgesia in the chemical pain test, that was not altered by systemic naloxone administration (1 mg/kg, s.c.). Intracerebroventricular administration of these drugs (0.1-10 micrograms) was ineffective in producing analgesia in acute thermal, mechanical and chemical pain tests. These results suggest that peripheral 5-HT3 receptors play a role in chemical, but not thermal or mechanical nociceptive mechanisms.
Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc
With a desire to increase health, cognitive performance effectiveness, and quality of life for su... more With a desire to increase health, cognitive performance effectiveness, and quality of life for submarine watch-standers underway, we performed an evaluation comparing an alternative, compressed-work (ALT) schedule, designed to enhance circadian rhythm entrainment and sleep hygiene, to the contemporary submarine (SUB) forward rotating schedule, aboard the ballistic-missile submarine, USS Henry M. Jackson (SSBN-730 Gold). We assessed a compressed close-6 watch-schedule ("ALT") relative to the existing backward rotating 6-hr on, 12-hr off 18-hr watch schedule ("SUB") employed underway aboard submarines. We monitored 40 subjects' sleep, and temperature and salivary cortisol from 10 of the 40 for approximately two weeks on each respective schedule underway. The cortisol cosinor mesors (midline estimating statistic of rhythm), and amplitudes did not differ significantly between conditions. The temperature cosinor mesors, and the cosinor amplitude were not significa...
Sleep
Introduction Alcohol is one of the most common psychoactive drugs that has depressant effects on ... more Introduction Alcohol is one of the most common psychoactive drugs that has depressant effects on the central nervous system. The vast majority of research on alcohol and sleep indicates chronic alcohol consumption has a detrimental impact on sleep architecture and homeostasis. However, less research has explored the effects of sleep deprivation on alcohol consumption; that is, the relationship in the opposite direction. Previous animal studies have explored a potential bi-directional relationship between sleep and alcohol with promising results. However, there was concern that the potential relationship may be a result of stress as a by-product of the sleep deprivation method. The present study examines the effect of sleep deprivation on voluntary alcohol consumption using two sleep deprivation methods in the rat, forced exercise wheels and the automated sleep deprivation system. Methods Twelve male Sprague-Dawley rats had ad libitum access to a 7% alcohol solution and water. Alcoho...
Sleep
Introduction Depression, sleep disturbances, and cognitive deficits often co-occur. Compared to n... more Introduction Depression, sleep disturbances, and cognitive deficits often co-occur. Compared to non-medicated controls, people using antidepressant medications (particularly serotonin agonists) often have improved sleep including increased slow wave sleep, quality and continuity. Improvements to cognition after antidepressant treatments are also common including benefits to reaction time, inhibition, and memory. Importantly, circadian deficits, including sleep onset latency, fragmentation, and phase shifts are common in patients with depression, yet the effect of antidepressant medication on circadian indicators is unclear. The current project examined sleep, circadian entrainment, and cognition in college students who were diagnosed with depression and using serotonin agonists and in those without depressive symptoms. Methods Participants completed cognitive tasks that assessed reaction time, memory, attention, inhibition, and logical reasoning via the Automated Neuropsychological ...
Sleep
Sleep loss has been shown to alter risk preference during decision-making. However, research in t... more Sleep loss has been shown to alter risk preference during decision-making. However, research in this area has largely focussed on the effects of total sleep deprivation (TSD), while evidence on the effects of sleep restriction (SR) or the potentially moderating role of sex on risk preference remains scarce and unclear. The present study investigated risky decision-making in 47 healthy young adults who were assigned to either of two counterbalanced protocols: well-rested (WR) and TSD, or WR and SR. Participants were assessed on the Lottery Choice Task (LCT), which requires a series of choices between two risky gambles with varying risk levels. Analyses on the pooled dataset indicated across all sleep conditions, participants were generally more risk-seeking when trying to minimise financial loss (LOSSES) than while trying to maximise financial gain (GAINS). On GAINS trials, female participants were more risk-averse during TSD and SR, whereas male participants remained unchanged. On L...
electromagnetic fields on melatonin and sleep in the rat
Sleep, Apr 1, 2018
a MEGA-PRESS sequence within three a priori voxels of interest: the ventromedial prefrontal corte... more a MEGA-PRESS sequence within three a priori voxels of interest: the ventromedial prefrontal cortex (vmPFC), dorsolateral prefrontal cortex (dlPFC) and parietal-occipital region. Spectra were collected for a variety of brain metabolites, including gamma-Aminobutyric acid (GABA). MRS data were processed using LCModel software and expressed as a ratio to creatine. A 10-min psychomotor vigilance test (PVT) was administered hourly throughout SD. The first three PVT bouts served as a measure of baseline performance. Individual mean response speed on the PVT was normalized to baseline and used as an index of subject-specific resilience to SD. Due to technical complications, dlPFC MRS data was unavailable for n=9 subjects and parietal-occipital MRS data was unavailable for n=3 subjects. Results: A Pearson's partial correlation, controlling for gender, showed that baseline levels of GABA in the vmPFC were significantly correlated with resilience index (r=0.38, p=0.015), such that higher levels of GABA were associated with greater resilience. GABA levels in the dlPFC (r=0.17, p=0.358) and parietal-occipital region (r=0.15, p=0.389) were not significantly correlated with resilience. Conclusion: Subjects with higher versus lower GABA levels in the vmPFC were more resilient to PVT impairment during SD. These findings suggest that inhibitory neurotransmitters, such as GABA, are potential predictors of resilience to SD-induced performance impairment. Elevated levels of GABA in the vmPFC may reduce sensitivity to distractions, allowing for improved sustained attention and optimal performance. Support (If Any): 0234
Sleep, Apr 1, 2018
custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for... more custom MATLAB code. Average density, amplitude, duration and sigma power were then calculated for each participant. Participants also completed a number of cognitive tasks, within three months of their overnight recordings, of which we focused on a subset of memory tasks from the WebCNP battery (webcnp.med.upenn.edu/battery). Results: Older age was associated with greater spindle density (β=0.24), lower sigma power (β=-0.39), smaller spindle amplitude (β=-0.43) and shorter spindle duration (β=-0.26). No significant differences in spindle characteristics between sexes were identified. Greater spindle density was associated with better delayed performance on the Short Visual Object Learning Task (i.e. number of shapes remembered following an ~25-minute delay after the initial presentation and recall of the shapes) (β=0.26). Spindle characteristics were not associated with general cognitive abilities. Conclusion: Moderate age-related differences in spindle characteristics were identified in this sample of adolescents. We also identified an association between spindle density and performance on an episodic, visual learning task, despite the fact that cognitive testing did not necessarily occur in immediate proximity to the sleep EEG recording. This suggests that the relationship between sleep spindles and cognition may reflect more than memory consolidation. For example, spindle density may be a marker of an individual's learning capacity or may reflect the maturity of certain brain networks which support learning ability. Support (If Any): AA021690 (DBC) and AA021696 (IMC+FCB).
The investigation was carried out in the Chronobiology and Sleep Lab (CASL) of the Warfighter Fat... more The investigation was carried out in the Chronobiology and Sleep Lab (CASL) of the Warfighter Fatigue Countermeasures Research and Development Program, Air Force Research Laboratory, Brooks AFB TX. The CASL was a temporal isolation facility dedicated to research on fatigue countermeasures that extend and enhance warfighter cognitive performance and physical endurance.
Nine male submariners participated as research subjects, two from fast attack submarines and seven from ballistic missile submarines. The participants experienced three watchstanding schedules: 18-hour 6-and-12, traditional 4-and-8, alternative schedule. The alternative schedule provided improved sleep and cognitive performance