Ventral medullary surface activity during sleep, waking, and anesthetic states in the goat

1994 ◽  
Vol 267 (4) ◽  
pp. R1154-R1160 ◽  
Author(s):  
D. M. Rector ◽  
D. Gozal ◽  
H. V. Forster ◽  
P. J. Ohtake ◽  
L. G. Pan ◽  
...  
Keyword(s):  
Surface Activity ◽  
Control Mechanisms ◽  
Rapid Eye Movement Sleep ◽  
Halothane Anesthesia ◽  
Quiet Sleep ◽  
Cardiorespiratory Control ◽  
State Dependent ◽  
Reflected Light ◽  
Average Activity ◽  
Ventral Medullary Surface

We examined activity, measured as changes in reflected light, from the surface of a rostral ventral medullary area that is involved in cardiorespiratory control. We collected images during sleep and waking states and during halothane anesthesia in five adult unrestrained goats. During quiet sleep, overall activity increased and overall variability decreased compared with waking levels, whereas rapid eye movement sleep increased variability, and average activity decreased to near-waking levels. Distinct regions of activation and suppression appeared during sleep states. Deep anesthesia decreased activity and minimized variation. We speculate that alterations in rostral ventral medullary surface activity may play a role in state-dependent changes in cardiorespiratory control mechanisms.

Mechanics of the rib cage and diaphragm during sleep

1977 ◽  
Vol 43 (4) ◽  
pp. 600-602 ◽  
Author(s):  
K. Tusiewicz ◽  
H. Moldofsky ◽  
A. C. Bryan ◽  
M. H. Bryan
Keyword(s):  
Tidal Volume ◽  
Supine Position ◽  
Marked Reduction ◽  
Normal Subjects ◽  
Upright Position ◽  
Rapid Eye Movement Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Rib Cage ◽  
The Subject

The pattern of motion of the rib cage and abdomen/diaphragm was studied in three normal subjects during sleep. Sleep state was monitored by electroencephalograph and electrocculograph. Intercostal electromyographs (EMG's) were recorded from the second interspace parasternally. Abdominothoracic motion was monitored with magnetometers and these signals calibrated by isovolume lines either immediately before going to sleep, or if there was movement, on awakening. Respiration was recorded using a jerkin plethysmograph. In the awake subject in the supine position, the rib cage contributed 44% to the tidal volume and had essentially the same contribution in quiet sleep. However, in active or rapid eye movement sleep the rib cage contribution fell to 19% of the tidal volume. This was accompanied by a marked reduction in the intercostal EMG. With the subject in the upright position the rib cage appears to be passively driven by the diaphragm. However, the present data suggest that active contraction of the intercostal muscles is required for normal rib cage expansion in the supine position.

Comparison of calibration methods for respiratory inductive plethysmography in infants

1987 ◽  
Vol 63 (5) ◽  
pp. 1853-1861 ◽  
Author(s):  
M. D. Revow ◽  
S. J. England ◽  
H. A. Stogryn ◽  
D. L. Wilkes
Keyword(s):  
Compartment Model ◽  
Sleep State ◽  
Quiet Sleep ◽  
Multiple Points ◽  
Rib Cage ◽  
Respiratory Inductive Plethysmography ◽  
State Dependent ◽  
Two Compartment Model ◽  
Calibration Methods ◽  
Substantial Change

In infants under the age of 6 mo respiratory inductive plethysmograph (RIP)-calculated tidal volumes (VT) were compared with simultaneously measured volumes using a pneumotachograph (PNT) to 1) assess whether using multiple points (MP) along the inspiratory profile of a breath is superior to using only VT when calculating volume-motion (VM) coefficients, 2) verify the assumption of independent contributions of the abdomen and rib cage to VT, which was accomplished by extending the normal RIP model to include a term representing interaction between these two compartments, and 3) investigate whether VM coefficients are sleep-state dependent. Neither use of multiple points nor inclusion of the interacting term improved the performance of the RIP over that observed using a simple two-compartment model with VT measurements. However, VM coefficients obtained during quiet sleep (QS) were not reliable when used during rapid-eye-movement (REM) sleep, suggesting that coefficients obtained during one sleep state may not be applicable to another state where there is a substantial change in the relative abdominal/rib cage contributions to VT.

Maturation of Kitten Ventral Medullary Surface Activity during Pressor Challenges

1995 ◽  
Vol 17 (4) ◽  
pp. 236-245 ◽  
Author(s):  
David Gozal ◽  
Xiao-Wei Dong ◽  
David M. Rector ◽  
Ronald M. Harper
Keyword(s):  
Surface Activity ◽  
Ventral Medullary Surface

Arousal pattern following central and obstructive breathing abnormalities in infants and children

1996 ◽  
Vol 81 (6) ◽  
pp. 2651-2657 ◽  
Author(s):  
Frances McNamara ◽  
Faiq G. Issa ◽  
Colin E. Sullivan
Keyword(s):  
Obstructive Sleep Apnea ◽  
Pediatric Population ◽  
Infants And Children ◽  
Clinical Severity ◽  
Rapid Eye Movement Sleep ◽  
Active Sleep ◽  
Quiet Sleep ◽  
Respiratory Events ◽  
Obstructive Sleep ◽  
In Infants And Children

McNamara, Frances, Faiq G. Issa, and Colin E. Sullivan.Arousal pattern following central and obstructive breathing abnormalities in infants and children. J. Appl. Physiol. 81(6): 2651–2657, 1996.—We analyzed the polysomnographic records of 15 children and 20 infants with obstructive sleep apnea (OSA) to examine the interaction between central and obstructive breathing abnormalities and arousal from sleep. Each patient was matched for age with an infant or child who had no OSA. We found that the majority of respiratory events in infants and children was not terminated with arousal. In children, arousals terminated 39.3 ± 7.2% of respiratory events during quiet sleep and 37.8 ± 7.2% of events during active (rapid-eye-movement) sleep. In infants, arousals terminated 7.9 ± 1.0% of events during quiet sleep and 7.9 ± 1.2% of events during active sleep. In both infants and children, however, respiratory-related arousals occurred more frequently after obstructive apneas and hypopneas than after central events. Spontaneous arousals occurred in all patients with OSA during quiet and active sleep. The frequency of spontaneous arousals was not different between children with OSA and their matched controls. During active sleep, however, infants with OSA had significantly fewer spontaneous arousals than did control infants. We conclude that arousal is not an important mechanism in the termination of respiratory events in infants and children and that electroencephalographic criteria are not essential to determine the clinical severity of OSA in the pediatric population.

scholarly journals Optical imaging of the ventral medullary surface across sleep-wake states

1999 ◽  
Vol 277 (4) ◽  
pp. R1239-R1245 ◽  
Author(s):  
C. A. Richard ◽  
D. M. Rector ◽  
R. K. Harper ◽  
R. M. Harper
Keyword(s):  
Standard Deviation ◽  
Optical Imaging ◽  
Spontaneous Activity ◽  
Eye Movement ◽  
Rem Sleep ◽  
Neural Activity ◽  
Sleep Onset ◽  
Quiet Sleep ◽  
Ventral Medullary Surface ◽  
Wavelength Light

We hypothesized that spontaneous activity declines over widespread areas of the cat ventral medullary surface (VMS) during rapid eye movement (REM) sleep. We assessed neural and hemodynamic activity, measured as changes in reflected 660- and 560-nm wavelength light, from the VMS during sleep and waking states in five adult, unrestrained cats and in two control cats. Relative to quiet sleep, overall activity declined, and variability, assessed by standard deviation, increased by 25% during REM sleep. Variability in activity during waking also increased by 45% over quiet sleep, but mean activity was unchanged. REM sleep onset was preceded by a reduction in the hemodynamic signal from 5 to 60 s before neural activity decline. The activity decline during REM sleep, previously noted in the goat rostral VMS, extends to intermediate VMS areas of the cat and differs from most neural sites, such as the cortex, hippocampus, and thalamus, which increase activity during REM sleep. The activity decline during REM sleep has the potential to modify VMS responsiveness to baroreceptor and chemoreceptor challenges during the REM state.

Importance of inspiratory muscle tone in maintenance of FRC in the newborn

1981 ◽  
Vol 51 (4) ◽  
pp. 830-834 ◽  
Author(s):  
J. Lopes ◽  
N. L. Muller ◽  
M. H. Bryan ◽  
A. C. Bryan
Keyword(s):  
Muscle Tone ◽  
Inspiratory Muscle ◽  
Rapid Eye Movement Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Rib Cage ◽  
Surface Electrodes ◽  
Inspiratory Muscles ◽  
Residual Capacity ◽  
Behavioral Criteria

The importance of inspiratory muscle tone in the maintenance of functional residual capacity (FRC) in newborns was studied in eight premature infants with birth weights of 1,166 +/- 217 g and gestational age 29 +/- 1.9 wk (mean +/- SD). Rib cage and abdominal anteroposterior diameters were monitored with magnetometers, and electromyograms of the diaphragm and intercostal muscles were recorded with surface electrodes. Sleep state was monitored using electrooculogram and behavioral criteria. We assessed the decrease in tonic activity of the inspiratory muscles and the fall in end-expiratory lung volume during apnea compared with the period just preceding apnea. A total of 98 apneas were analyzed. In all instances a decrease in diaphragmatic and intercostal tone was associated with a decrease in the anteroposterior diameter of both rib cage and abdomen, indicating a fall in FRC. These changes were more marked during quiet sleep than during rapid-eye-movement sleep (P less than 0.01). Our results suggest that inspiratory muscle tone is a major determinant of FRC in the newborn.

Ventral medullary surface activity during hypoxia in awake and anesthetized goats

1996 ◽  
Vol 103 (1) ◽  
pp. 45-56 ◽  
Author(s):  
H.V. Forster ◽  
D. Gozal ◽  
R.M. Harper ◽  
T.F. Lowry ◽  
P.J. Ohtake ◽  
...  
Keyword(s):  
Surface Activity ◽  
Ventral Medullary Surface

Cutaneous responsiveness of lumbar spinal neurons in awake and halothane-anesthetized sheep

1995 ◽  
Vol 74 (4) ◽  
pp. 1549-1562 ◽  
Author(s):  
J. F. Herrero ◽  
P. M. Headley
Keyword(s):  
Dynamic Range ◽  
High Threshold ◽  
Relative Distribution ◽  
Control Mechanisms ◽  
Spinal Neurons ◽  
Halothane Anesthesia ◽  
Sensory Stimuli ◽  
Low Threshold ◽  
Wdr Neurons ◽  
Lumbar Spinal

1. To compare the responsiveness of lumbar spinal neurons to peripheral sensory stimuli under normal physiological conditions and under halothane anesthesia, we performed a study in sheep that were prepared chronically. This permitted recordings to be made in the same animals either when they were awake and free from recent surgery, drugs, and training and only partially restrained or when they were anesthetized with halothane. 2. We recorded 261 units in dorsal and ventral horns under conscious conditions. Of these, 19% had no detectable receptive field (RF) and 44% had responses dominated by proprioceptive inputs; these units were not investigated in detail. The remaining 96 neurons (37%) had clearly defined cutaneous RFs. Of these, most (72%) had wide-dynamic-range (WDR; convergent, multireceptive) properties, 19% were low-threshold mechanoreceptive (LTMR), and 9% were high-threshold mechanoreceptive (HTMR). These units with cutaneous RFs were investigated in greater detail. 3. The spontaneous activity under these awake conditions was low (< 4 spikes/s) for nearly all units in all three categories. The mechanical threshold of the most sensitive (central) part of the cutaneous RF was assessed with von Frey bristles. Thresholds were < 5 mN for all LTMR neurons, < 1-30 mN for WDR neurons, and > 80 mN for HTMR neurons. The size of the low-threshold cutaneous RFs was significantly larger for WDR neurons (mean 46 cm2) and HTMR neurons (45 cm2) than for LTMR neurons (24 cm2). The RFs were distributed all over the ipsilateral hindlimb. Large RFs were mostly proximal, whereas small RFs were distributed relatively evenly over the limb. 4. Recordings were made from a further 165 units while the animals were under halothane anesthesia. With 86 neurons having cutaneous peripheral RFs, the proportions having LTMR, HTMR, or WDR characteristics were very similar to those in awake animals. Under halothane the ongoing activity of WDR units was slightly (but significantly) less. The threshold to von Frey bristle stimulation was significantly higher only for WDR units, in both dorsal and ventral horns. The mean size of cutaneous RFs was significantly larger in all classes of units recorded under halothane anesthesia. For WDR units this was true for cells in both dorsal and ventral horns. This effect on mean values was due to a larger proportion of units with very large fields under anesthesia, particularly in the dorsal horn. 5. Comparison of the data from conscious animals with published results of acute experiments indicates that acute recording conditions do not distort the relative distribution and resting characteristics of these three functional categories of lumbar spinal neurons as much as might have been expected. 6. Halothane does not have major effects on the resting sensory responsiveness of spinal neurons with cutaneous RFs. The increase in RF area, which contrasts with most results from acute studies, is likely to be due to a dampening of descending inhibitory control mechanisms.

Diaphragmatic muscle tone

1979 ◽  
Vol 47 (2) ◽  
pp. 279-284 ◽  
Author(s):  
N. Muller ◽  
G. Volgyesi ◽  
L. Becker ◽  
M. H. Bryan ◽  
A. C. Bryan
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Animal Studies ◽  
Muscle Tone ◽  
Muscle Spindles ◽  
Rapid Eye Movement ◽  
Tonic Activity ◽  
Halothane Anesthesia ◽  
Quiet Sleep ◽  
Diaphragmatic Muscle

It is generally believed that there is a scarcity of muscle spindles in the diaphragm and that there is no tonic activity at end expiration. This conclusion is based mainly on animal studies and the difficulty in differentiating tonic electromyogram activity from noise. We have, however, found a number of muscle spindles in the newborn human diagphragm, concentrated in the region of the central tendon. We also tried to detect tonic activity by decreasing it (by rapid-eye movement (REM) sleep or anesthesia) or increasing it (with abdominal loading). During REM sleep in five infants and five adults, using subcostal electrodes were observed a marked fall in tonic activity (P less than 0.001) compared to non-REM or quiet sleep. We also observed a reduction in diaphragmatic tonic activity with halothane anesthesia (P less than 0.001). With esophageal electrodes in adult subjects, there was a rise in tonic diaphragmatic activity proportional to the amount of abdomina load (P less than 0.001). We conclude that there are muscle spindles in the human diaphragm and that there is tonic activity at end expiration.

Sleep Apnea in Infants Who Succumb to The Sudden Infant Death Syndrome

PEDIATRICS ◽  
1991 ◽  
Vol 87 (6) ◽  
pp. 841-846
Author(s):  
Vicki L. Schechtman ◽  
Ronald M. Harper ◽  
Adrian J. Wilson ◽  
David P. Southall
Keyword(s):  
Sleep Apnea ◽  
Eye Movement ◽  
Sudden Infant Death Syndrome ◽  
Infant Death ◽  
Matched Control ◽  
Sudden Infant Death ◽  
Sudden Infant ◽  
Rapid Eye Movement ◽  
Rapid Eye Movement Sleep ◽  
Quiet Sleep

Previous studies have shown the frequency of respiratory pauses to be altered in groups of infants at risk for the sudden infant death syndrome (SIDS). In this study, we assess the frequency of apneic pauses during quiet sleep and rapid eye movement sleep in control infants and infants who subsequently died of SIDS. Sleep states were identified in 12-hour physiological recordings of SIDS victims and matched control infants, and the number of respiratory pauses from 4 to 30 seconds in duration was computed for quiet sleep and rapid eye movement sleep. SIDS victims 40 to 65 days of age showed significantly fewer apneic pauses than did age-matched control infants across the two sleep states. Fewer short respiratory pauses accounted for most of the reduction in number of apneic events in the SIDS victims during both sleep states. During the first month of life, SIDS victims did not differ significantly from control neonates on this measure. The finding that this respiratory difference exists during the second month of life, just before the period of maximal risk for SIDS, but not earlier, may have implications for the etiology of SIDS deaths.

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