Sleep/Wake Firing Patterns of Human Genioglossus Motor Units

2007 ◽  
Vol 98 (6) ◽  
pp. 3284-3291 ◽  
Author(s):  
E. Fiona Bailey ◽  
Keith W. Fridel ◽  
Amber D. Rice
Keyword(s):  
Temporal Relationship ◽  
Motor Units ◽  
Nrem Sleep ◽  
Future Research ◽  
Mechanical Environment ◽  
Firing Patterns ◽  
Obstructive Sleep ◽  
Respiratory Modulation ◽  
Discharge Patterns ◽  
Whole Muscle

Although studies of the principal tongue protrudor muscle genioglossus (GG) suggest that whole muscle GG electromyographic (EMG) activities are preserved in nonrapid eye movement (NREM) sleep, it is unclear what influence sleep exerts on individual GG motor unit (MU) activities. We characterized the firing patterns of human GG MUs in wakefulness and NREM sleep with the aim of determining 1) whether the range of MU discharge patterns evident in wakefulness is preserved in sleep and 2) what effect the removal of the “wakefulness” input has on the magnitude of the respiratory modulation of MU activities. Microelectrodes inserted into the extrinsic tongue protrudor muscle, the genioglossus, were used to follow the discharge of single MUs. We categorized MU activities on the basis of the temporal relationship between the spike train and the respiration cycle and quantified the magnitude of the respiratory modulation of each MU using the eta (η2) index, in wakefulness and sleep. The majority of MUs exhibited subtle increases or decreases in respiratory modulation but were otherwise unaffected by NREM sleep. In contrast, 30% of MUs exhibited marked sleep-associated changes in discharge frequency and respiratory modulation. We suggest that GG MUs should not be considered exclusively tonic or phasic; rather, the discharge pattern appears to be a flexible feature of GG activities in healthy young adults. Whether such flexibility is important in the response to changes in the chemical and/or mechanical environment and whether it is preserved as a function of aging or in individuals with obstructive sleep apnea are critical questions for future research.

scholarly journals An Approach for Simulation of the Muscle Force Modeling It by Summation of Motor Unit Contraction Forces

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Rositsa Raikova ◽  
Hristo Aladjov ◽  
Jan Celichowski ◽  
Piotr Krutki
Keyword(s):  
Muscle Force ◽  
Cumulative Effect ◽  
Motor Units ◽  
Medial Gastrocnemius ◽  
Size Principle ◽  
Firing Patterns ◽  
Force Modeling ◽  
The Individual ◽  
Whole Muscle ◽  
Medial Gastrocnemius Muscle

Muscle force is due to the cumulative effect of repetitively contracting motor units (MUs). To simulate the contribution of each MU to whole muscle force, an approach implemented in a novel computer program is proposed. The individual contraction of an MU (the twitch) is modeled by a 6-parameter analytical function previously proposed; the force of one MU is a sum of its contractions due to an applied stimulation pattern, and the muscle force is the sum of the active MUs. The number of MUs, the number of slow, fast-fatigue-resistant, and fast-fatigable MUs, and their six parameters as well as a file with stimulation patterns for each MU are inputs for the developed software. Different muscles and different firing patterns can be simulated changing the input data. The functionality of the program is illustrated with a model consisting of 30 MUs of rat medial gastrocnemius muscle. The twitches of these MUs were experimentally measured and modeled. The forces of the MUs and of the whole muscle were simulated using different stimulation patterns that included different regular, irregular, synchronous, and asynchronous firing patterns of MUs. The size principle of MUs for recruitment and derecruitment was also demonstrated using different stimulation paradigms.

scholarly journals Respiratory and Mayer wave-related discharge patterns of raphé and pontine neurons change with vagotomy

2010 ◽  
Vol 109 (1) ◽  
pp. 189-202 ◽  
Author(s):  
K. F. Morris ◽  
S. C. Nuding ◽  
L. S. Segers ◽  
D. M. Baekey ◽  
R. Shannon ◽  
...  
Keyword(s):  
Respiratory Rhythm ◽  
Respiratory Drive ◽  
Lung Inflation ◽  
Firing Patterns ◽  
Cross Correlation Analysis ◽  
Before And After ◽  
Respiratory Modulation ◽  
Discharge Patterns ◽  
Mayer Wave ◽  
Raphe Neurons

Previous models have attributed changes in respiratory modulation of pontine neurons after vagotomy to a loss of pulmonary stretch receptor “gating” of an efference copy of inspiratory drive. Recently, our group confirmed that pontine neurons change firing patterns and become more respiratory modulated after vagotomy, although average peak and mean firing rates of the sample did not increase (Dick et al., J Physiol 586: 4265–4282, 2008). Because raphé neurons are also elements of the brain stem respiratory network, we tested the hypotheses that after vagotomy raphé neurons have increased respiratory modulation and that alterations in their firing patterns are similar to those seen for pontine neurons during withheld lung inflation. Raphé and pontine neurons were recorded simultaneously before and after vagotomy in decerebrated cats. Before vagotomy, 14% of 95 raphé neurons had increased activity during single respiratory cycles prolonged by withholding lung inflation; 13% exhibited decreased activity. After vagotomy, the average index of respiratory modulation (η2) increased (0.05 ± 0.10 to 0.12 ± 0.18 SD; Student's paired t-test, P < 0.01). Time series and frequency domain analyses identified pontine and raphé neuron firing rate modulations with a 0.1-Hz rhythm coherent with blood pressure Mayer waves. These “Mayer wave-related oscillations” (MWROs) were coupled with central respiratory drive and became synchronized with the central respiratory rhythm after vagotomy (7 of 10 animals). Cross-correlation analysis identified functional connectivity in 52 of 360 pairs of neurons with MWROs. Collectively, the results suggest that a distributed network participates in the generation of MWROs and in the coordination of respiratory and vasomotor rhythms.

scholarly journals Shining a Light on the Mechanisms of Sleep for Memory Consolidation

2021 ◽  
Author(s):  
Michelle A. Frazer ◽  
Yesenia Cabrera ◽  
Rockelle S. Guthrie ◽  
Gina R. Poe
Keyword(s):  
Rem Sleep ◽  
Neural Activity ◽  
Memory Consolidation ◽  
Strong Support ◽  
Nrem Sleep ◽  
Future Research ◽  
Sleep Spindles ◽  
Slow Oscillations ◽  
Theta Waves ◽  
Learning Tasks

Abstract Purpose of review This paper reviews all optogenetic studies that directly test various sleep states, traits, and circuit-level activity profiles for the consolidation of different learning tasks. Recent findings Inhibiting or exciting neurons involved either in the production of sleep states or in the encoding and consolidation of memories reveals sleep states and traits that are essential for memory. REM sleep, NREM sleep, and the N2 transition to REM (characterized by sleep spindles) are integral to memory consolidation. Neural activity during sharp-wave ripples, slow oscillations, theta waves, and spindles are the mediators of this process. Summary These studies lend strong support to the hypothesis that sleep is essential to the consolidation of memories from the hippocampus and the consolidation of motor learning which does not necessarily involve the hippocampus. Future research can further probe the types of memory dependent on sleep-related traits and on the neurotransmitters and neuromodulators required.

Arterial blood pressure responses to graded transient arousal from sleep in normal humans

1993 ◽  
Vol 74 (3) ◽  
pp. 1123-1130 ◽  
Author(s):  
R. J. Davies ◽  
P. J. Belt ◽  
S. J. Roberts ◽  
N. J. Ali ◽  
J. R. Stradling
Keyword(s):  
Blood Pressure ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Confidence Interval ◽  
Rem Sleep ◽  
High Frequency ◽  
Pressure Rise ◽  
Nrem Sleep ◽  
Blood Pressure Rise ◽  
Obstructive Sleep

During obstructive sleep apnea, transient arousal at the resumption of breathing is coincident with a substantial rise in blood pressure. To assess the hemodynamic effect of arousal alone, 149 transient stimuli were administered to five normal subjects. Two electroencephalograms (EEG), an electrooculogram, a submental electromyogram (EMG), and beat-to-beat blood pressure (Finapres, Ohmeda) were recorded in all subjects. Stimulus length was varied to produce a range of cortical EEG arousals that were graded as follows: 0, no increase in high-frequency EEG or EMG; 1, increased high-frequency EEG and/or EMG for < 10 s; 2, increased high-frequency EEG and/or EMG for > 10 s. Overall, compared with control values, average systolic pressure rose [nonrapid-eye-movement (NREM) sleep 10.0 +/- 7.69 (SD) mmHg; rapid-eye-movement (REM) sleep 6.0 +/- 6.73 mmHg] and average diastolic pressure rose (NREM sleep 6.1 +/- 4.43 mmHg; REM sleep 3.7 +/- 3.02 mmHg) over the 10 s following the stimulus (NREM sleep, P < 0.0001; REM sleep, P < 0.002). During NREM sleep, there was a trend toward larger blood pressure rises at larger grades of arousal (systolic: r = 0.22, 95% confidence interval 0.02–0.40; diastolic: r = 0.48, 95% confidence interval 0.31–0.62). The average blood pressure rise in response to the grade 2 arousals was approximately 75% of that during obstructive sleep apnea. Arousal stimuli that did not cause EEG arousal still produced a blood pressure rise (mean systolic rise 8.6 +/- 7.0 mmHg, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

393 Comparison of Oxygenation Abnormalities Between Obstructive Sleep Apnea and Central Sleep Apnea

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A156-A157
Author(s):  
Sikawat Thanaviratananich ◽  
Hao Cheng ◽  
Maria Pino ◽  
Krishna Sundar
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Demographic Data ◽  
Central Sleep Apnea ◽  
Nrem Sleep ◽  
Rate Of Change ◽  
Apnea Hypopnea Index ◽  
P Value ◽  
Obstructive Sleep ◽  
Cheyne Stokes Breathing

Abstract Introduction The apnea-hypopnea index (AHI) is used as a generic index to quantify both central sleep apnea (CSA) and obstructive sleep apnea (OSA) syndromes. Patterns of oxygenation abnormalities seen in CSA and OSA may be key to understanding differing clinical impacts of these disorders. Oxygen desaturation and resaturation slopes and durations in OSA and CSA were compared between OSA and CSA patients. Methods Polysomnographic data of patients aged 18 years or older with diagnosis of OSA and CSA, at University of Iowa Hospitals and Clinics, were analyzed and demographic data were collected. Oximetric changes during hypopneas and apneas were studied for desaturation/resaturation durations and desaturation/resaturation slopes. Desaturation and resaturation slopes were calculated as rate of change in oxygen saturation (ΔSpO2/Δtime). Comparison of hypoxemia-based parameters between patients with OSA and CSA was performed using unpaired t-test. Results 32 patients with OSA with median AHI of 15.4 (IQR 5.1 to 30.55) and median ODI of 15.47 (IQR 9.50 to 29.33) were compared to 15 patients with CSA with a median AHI of 20.4 (IQR 12.6 to 47.8) and median ODI of 27.56 (IQR 17.99 to 29.57). The mean number of desaturation and resaturation events was not significantly different between patients with OSA and CSA (OSA - 106.81±87.93; CSA - 130.67±76.88 with a p-value 0.1472). 4/15 CSA patients had Cheyne-Stokes breathing, 2/15 had treatment emergent central sleep apnea, 1/15 had methadone-associated CSA and for 8/15, no etiologies for CSA were found. Mean desaturation durations was significantly longer in OSA (20.84 s ± 5.67) compared to CSA (15.94 s ± 4.54) (p=0.0053) and consequently the desaturation slopes were steeper in CSA than OSA (-0.35%/sec ±0.180 vs. -0.243 ± 0.073; p=0.0064). The resaturation duration was not significantly longer in OSA (9.76 s ± 2.02) than CSA (9.057 s ± 2.17) (p=0.2857). Differences between desaturation duration and slopes between CSA and OSA persisted during REM and NREM sleep, and in supine sleep. Conclusion As compared to OSA, patients with CSA have different patterns of desaturations and resaturations with lesser hypoxic burden with CSA. This may have implications on the clinical outcomes seen between these two disorders. Support (if any):

Shar Pei Larynx: Supraglottic and Postcricoid Mucosal Redundancy and Its Association With Medical Comorbidities

2018 ◽  
Vol 128 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Yin Yiu ◽  
Kathleen M. Tibbetts ◽  
C. Blake Simpson ◽  
Laura A. Matrka
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Laryngopharyngeal Reflux ◽  
Tertiary Care ◽  
Retrospective Chart Review ◽  
Future Research ◽  
Morbidly Obese ◽  
Reflux Symptom Index ◽  
Symptom Index ◽  
Obstructive Sleep

Objectives: The aim of this study is to describe a clinical entity the authors term “Shar Pei larynx,” characterized by redundant supraglottic and postcricoid mucosa that the authors hypothesize coexists in patients with obstructive sleep apnea, laryngopharyngeal reflux, and obesity. By exploring this hypothesis, the authors hope to set the foundation for future research with the goal of identifying whether Shar Pei larynx is a marker for untreated sleep apnea or other diseases. Study Design: Retrospective chart review. Setting: Two tertiary care academic institutions. Methods: Data were collected from a 5-year period by querying for patients described to have “Shar Pei larynx” or “posterior supraglottic and/or postcricoid mucosal redundancy” on laryngoscopic findings. Relevant demographic and clinical characteristics were analyzed, with a focus on associations with obesity, sleep apnea, and laryngopharyngeal reflux. Results: Thirty-two patients were identified with physical findings consistent with Shar Pei larynx. Twenty-six patients (81.3%) were obese; 16 (50%) were morbidly obese. Twenty-two patients (68.8%) either had an existing diagnosis of obstructive sleep apnea or were diagnosed on polysomnography performed after initial evaluation. Sixteen patients (50%) had type 2 diabetes mellitus, and 87.5% of these patients were obese. Twenty-eight patients (87.5%) noted histories of reflux, with a median reflux symptom index of 27 of 45. Five patients underwent procedures to reduce mucosal redundancy related to Shar Pei larynx. Conclusions: This pilot study confirms that the majority of patients diagnosed with Shar Pei larynx also had diagnoses of obesity, obstructive sleep apnea, and reflux disease. The demonstrated association is strong enough to warrant further study.

Discharge patterns in human motor units during fatiguing arm movements

1998 ◽  
Vol 85 (5) ◽  
pp. 1684-1692 ◽  
Author(s):  
L. Griffin ◽  
S. J. Garland ◽  
T. Ivanova
Keyword(s):  
Voluntary Movement ◽  
Motor Units ◽  
Constant Load ◽  
Short Isis ◽  
Interspike Intervals ◽  
Triceps Brachii ◽  
Movement Initiation ◽  
Human Motor ◽  
Discharge Patterns ◽  
Human Motor Units

The purpose of this study was to determine whether short interspike intervals (ISIs of <20 ms) would occur naturally during voluntary movement and would increase in number with fatigue. Thirty-four triceps brachii motor units from nine subjects were assessed during a fatigue task consisting of fifty extension and fifty flexion elbow movements against a constant-load opposing extension. Nineteen motor units were recorded from the beginning of the fatigue task; the number of short ISIs was 7.1 ± 4.1% of the total number of ISIs in the first one-third of the task (unfatigued state). This value increased to 11.8 ± 5.9% for the last one-third of the task (fatigued state). Fifteen motor units were recruited during the fatigue task and discharged, with 16.4 ± 6.0% of short ISIs in the fatigued state. For all motor units, the number of short ISIs was positively correlated ( r 2 = 0.85) with the recruitment threshold torque. Short ISIs occurred most frequently at movement initiation but also occurred throughout the movement. These results document the presence of short ISIs during voluntary movement and their increase in number during fatigue.

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