Synchrony between breathing and shivering in three muscles of bantam hens exposed to cold eggs

1993 ◽  
Vol 265 (6) ◽  
pp. R1439-R1446
Author(s):  
O. Toien
Keyword(s):  
Cold Water ◽  
Motor Units ◽  
Respiratory Frequency ◽  
Emg Activity ◽  
Average Intensity ◽  
Respiratory Drive ◽  
Pectoralis Muscle ◽  
Pectoralis Muscles ◽  
The Brain ◽  
Muscle Circulation

Unrestrained, incubating bantam hens (Gallus domesticus) were exposed to cold, water-perfused eggs to induce shivering. Mean rectified electromyogram (EMG activity) was recorded from the iliotibialis, gastrocnemius, and pectoralis muscles, together with breathing and O2 consumption. EMG activity in all three muscles varied in synchrony with breathing, as confirmed by spectral analysis. The highest shivering intensity occurred during end expiration. This synchrony was also present when respiratory frequency was increased by hypercapnic/hypoxic stimuli and tended to improve with increasing respiratory frequency and tidal volume. The absolute modulation of shivering intensity remained relatively constant with increasing average intensity, indicating that breathing-modulated motor units are activated first. In the less active pectoralis muscle, all activity was modulated. Modulation is probably not restricted to one type of muscle fiber because it occurs in both predominantly red hindquarter muscles and the white pectoralis muscle. It is tentatively suggested that respiratory drive-related influence from the brain stem has a synchronizing effect on spinal cord activity. A bursting activity pattern may be more favorable for muscle circulation than a tonic discharge pattern.

scholarly journals Common drive to the upper airway muscle genioglossus during inspiratory loading

2015 ◽  
Vol 114 (5) ◽  
pp. 2883-2892 ◽  
Author(s):  
Michael J. Woods ◽  
Christian L. Nicholas ◽  
John G. Semmler ◽  
Julia K. M. Chan ◽  
Amy S. Jordan ◽  
...  
Keyword(s):  
Upper Airway ◽  
Motor Units ◽  
Quadratic Functions ◽  
Emg Activity ◽  
Respiratory Drive ◽  
Activation Effect ◽  
Single Motor Unit ◽  
Common Drive ◽  
Load Discharge ◽  
Inspiratory Load

Common drive is thought to constitute a central mechanism by which the efficiency of a motor neuron pool is increased. This study tested the hypothesis that common drive to the upper airway muscle genioglossus (GG) would increase with increased respiratory drive in response to an inspiratory load. Respiration, GG electromyographic (EMG) activity, single-motor unit activity, and coherence in the 0–5 Hz range between pairs of GG motor units were assessed for the 30 s before an inspiratory load, the first and second 30 s of the load, and the 30 s after the load. Twelve of twenty young, healthy male subjects provided usable data, yielding 77 pairs of motor units: 2 Inspiratory Phasic, 39 Inspiratory Tonic, 15 Expiratory Tonic, and 21 Tonic. Respiratory and GG inspiratory activity significantly increased during the loads and returned to preload levels during the postload periods (all showed significant quadratic functions over load trials, P < 0.05). As hypothesized, common drive increased during the load in inspiratory modulated motor units to a greater extent than in expiratory/tonic motor units (significant load × discharge pattern interaction, P < 0.05). Furthermore, this effect persisted during the postload period. In conclusion, common drive to inspiratory modulated motor units was elevated in response to increased respiratory drive. The postload elevation in common drive was suggestive of a poststimulus activation effect.

scholarly journals Backward walking highlights gait asymmetries in children with cerebral palsy

2018 ◽  
Vol 119 (3) ◽  
pp. 1153-1165 ◽  
Author(s):  
Germana Cappellini ◽  
Francesca Sylos-Labini ◽  
Michael J. MacLellan ◽  
Annalisa Sacco ◽  
Daniela Morelli ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Muscle Activation ◽  
Pattern Generation ◽  
Comprehensive Assessment ◽  
Emg Activity ◽  
Backward Walking ◽  
Spinal Circuitry ◽  
Children With Cerebral Palsy ◽  
Control Circuits ◽  
The Brain

To investigate how early injuries to developing motor regions of the brain affect different forms of gait, we compared the spatiotemporal locomotor patterns during forward (FW) and backward (BW) walking in children with cerebral palsy (CP). Bilateral gait kinematics and EMG activity of 11 pairs of leg muscles were recorded in 14 children with CP (9 diplegic, 5 hemiplegic; 3.0–11.1 yr) and 14 typically developing (TD) children (3.3–11.8 yr). During BW, children with CP showed a significant increase of gait asymmetry in foot trajectory characteristics and limb intersegmental coordination. Furthermore, gait asymmetries, which were not evident during FW in diplegic children, became evident during BW. Factorization of the EMG signals revealed a comparable structure of the motor output during FW and BW in all groups of children, but we found differences in the basic temporal activation patterns. Overall, the results are consistent with the idea that both forms of gait share pattern generation control circuits providing similar (though reversed) kinematic patterns. However, BW requires different muscle activation timings associated with muscle modules, highlighting subtle gait asymmetries in diplegic children, and thus provides a more comprehensive assessment of gait pathology in children with CP. The findings suggest that spatiotemporal asymmetry assessments during BW might reflect an impaired state and/or descending control of the spinal locomotor circuitry and can be used for diagnostic purposes and as complementary markers of gait recovery.NEW & NOTEWORTHY Early injuries to developing motor regions of the brain affect both forward progression and other forms of gait. In particular, backward walking highlights prominent gait asymmetries in children with hemiplegia and diplegia from cerebral palsy and can give a more comprehensive assessment of gait pathology. The observed spatiotemporal asymmetry assessments may reflect both impaired supraspinal control and impaired state of the spinal circuitry.

Diaphragmatic activity during REM sleep in the adult cat

1996 ◽  
Vol 81 (2) ◽  
pp. 751-760 ◽  
Author(s):  
J. Orem ◽  
C. A. Anderson
Keyword(s):  
Rem Sleep ◽  
Area Under The Curve ◽  
Motor Units ◽  
Nrem Sleep ◽  
Respiratory Drive ◽  
Upper Airways ◽  
Central Respiratory Activity ◽  
Time Average ◽  
Adult Cat ◽  
Adult Cats

Diaphragmatic electromyograms from five adult cats were studied to determine whether diaphragmatic activity, like central respiratory activity, increases in rapid-eye-movement (REM) sleep. Breaths with inspiratory durations between 250 and 2,000 ms were analyzed. 1) There was a greater slope of the moving time average of diaphragmatic activity in REM than in non-REM (NREM) sleep. These greater slopes occurred whether the route of breathing was through the upper airways or through an endotracheal tube and may have resulted from early recruitment of motor units. 2) Mean diaphragmatic activity was also greater, but other variables (peak activity, the area under the curve of diaphragmatic activity, mean intratracheal pressures, inspiratory airflow rates, and tidal volumes) were not greater in REM than in NREM sleep. 3) Diaphragmatic activity was similar in REM sleep and active wakefulness. 4) Across states, slope of the moving time average varied with the duration of inspiration: greater slopes were associated with shorter breaths. These results are consistent with an increase in central respiratory drive in REM sleep that increases the rate of rise of diaphragmatic activity.

Reflex responses in active muscles elicited by stimulation of low-threshold afferents from the human foot

1992 ◽  
Vol 67 (5) ◽  
pp. 1375-1384 ◽  
Author(s):  
A. M. Aniss ◽  
S. C. Gandevia ◽  
D. Burke
Keyword(s):  
Motor Units ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Onset Latency ◽  
Single Motor ◽  
Reflex Responses ◽  
Posterior Tibial ◽  
Single Motor Units ◽  
Low Threshold ◽  
Stimulation Of

1. Reflex responses were elicited in muscles that act at the ankle by electrical stimulation of low-threshold afferents from the foot in human subjects who were reclining supine. During steady voluntary contractions, stimulus trains (5 pulses at 300 Hz) were delivered at two intensities to the sural nerve (1.2-4.0 times sensory threshold) or to the posterior tibial nerve (1.1-3.0 times motor threshold for the intrinsic muscles of the foot). Electromyographic (EMG) recordings were made from tibialis anterior (TA), peroneus longus (PL), soleus (SOL), medial gastrocnemius (MG), and lateral gastrocnemius (LG) muscles by the use of intramuscular wire electrodes. 2. As assessed by averages of rectified EMG, stimulation of the sural or posterior tibial nerves at nonpainful levels evoked a complex oscillation with onset latencies as early as 40 ms and lasting up to 200 ms in each muscle. The most common initial responses in TA were a decrease in EMG activity at an onset latency of 54 ms for sural stimuli, and an increase at an onset latency of 49 ms for posterior tibial stimuli. The response of PL to stimulation of the two nerves began with a strong facilitation of 44 ms (sural) and 49 ms (posterior tibial). With SOL, stimulation of both nerves produced early inhibition beginning at 45 and 50 ms, respectively. With both LG and MG, sural stimuli produced an early facilitation at 52-53 ms. However, posterior tibial stimuli produced different initial responses in these two muscles: facilitation in LG at 50 ms and inhibition in MG at 51 ms. 3. Perstimulus time histograms of the discharge of 61 single motor units revealed generally similar reflex responses as in multiunit EMG. However, different reflex components were not equally apparent in the responses of different single motor units: an individual motor unit could respond slightly differently with a change in stimulus intensity or background contraction level. The multiunit EMG record represents a global average that does not necessarily depict the precise pattern of all motor units contributing to the average. 4. When subjects stood erect without support and with eyes closed, reflex patterns were seen only in active muscles, and the patterns were similar to those in the reclining posture. 5. It is concluded that afferents from mechanoreceptors in the sole of the foot have multisynaptic reflex connections with the motoneuron pools innervating the muscles that act at the ankle. When the muscles are active in standing or walking, cutaneous feedback may play a role in modulating motoneuron output and thereby contribute to stabilization of stance and gait.

EMG Changes in Human Thenar Motor Units With Force Potentiation and Fatigue

2006 ◽  
Vol 95 (3) ◽  
pp. 1518-1526 ◽  
Author(s):  
C. K. Thomas ◽  
R. S. Johansson ◽  
B. Bigland-Ritchie
Keyword(s):  
Motor Unit ◽  
Motor Units ◽  
Emg Activity ◽  
Single Motor Unit ◽  
Tetanic Force ◽  
Twitch Force ◽  
Emg Amplitude ◽  
Before And After ◽  
Induced Changes ◽  
Motor Unit Emg

Few studies have analyzed activity-induced changes in EMG activity in individual human motor units. We studied the changes in human thenar motor unit EMG that accompany the potentiation of twitch force and fatigue of tetanic force. Single motor unit EMG and force were recorded in healthy subjects in response to selective stimulation of their motor axons within the median nerve just above the elbow. Twitches were recorded before and after a series of pulse trains delivered at frequencies that varied between 5 and 100 Hz. This stimulation induced significant increases in EMG amplitude, duration, and area. However, in relative terms, all of these EMG changes were substantially smaller than the potentiation of twitch force. Another 2 min of stimulation (13 pulses at 40 Hz each second) induced additional potentiation of EMG amplitude, duration, and area, but the tetanic force from every unit declined. Thus activity-induced changes in human thenar motor unit EMG do not indicate the alterations in force or vice versa. These data suggest that different processes underlie the changes in EMG and force that occur during human thenar motor unit activity.

scholarly journals High-density surface electromyography maps after computer-aided training in individual with congenital transverse deficiency: a case study

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Katarzyna Kisiel-Sajewicz ◽  
Jarosław Marusiak ◽  
Mónica Rojas-Martínez ◽  
Damian Janecki ◽  
Sławomir Chomiak ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Upper Limb ◽  
Trapezius Muscle ◽  
High Density ◽  
Emg Activity ◽  
Average Intensity ◽  
Mental Training ◽  
Sensory Stimuli ◽  
Computer Aided ◽  
Before And After

Abstract Background The aim of this study was to determine whether computer-aided training (CAT) of motor tasks would increase muscle activity and change its spatial distribution in a patient with a bilateral upper-limb congenital transverse deficiency. We believe that our study makes a significant contribution to the literature because it demonstrates the usefulness of CAT in promoting the neuromuscular adaptation in people with congenital limb deficiencies and altered body image. Case presentation The patient with bilateral upper-limb congenital transverse deficiency and the healthy control subject performed 12 weeks of the CAT. The subject’s task was to imagine reaching and grasping a book with the hand. Subjects were provided a visual animation of that movement and sensory feedback to facilitate the mental engagement to accomplish the task. High-density electromyography (HD-EMG; 64-electrode) were collected from the trapezius muscle during a shrug isometric contraction before and after 4, 8, 12 weeks of the training. After training, we observed in our patient changes in the spatial distribution of the activation, and the increased average intensity of the EMG maps and maximal force. Conclusions These results, although from only one patient, suggest that mental training supported by computer-generated visual and sensory stimuli leads to beneficial changes in muscle strength and activity. The increased muscle activation and changed spatial distribution of the EMG activity after mental training may indicate the training-induced functional plasticity of the motor activation strategy within the trapezius muscle in individual with bilateral upper-limb congenital transverse deficiency. Marked changes in spatial distribution during the submaximal contraction in the patient after training could be associated with changes of the neural drive to the muscle, which corresponds with specific (unfamiliar for patient) motor task. These findings are relevant to neuromuscular functional rehabilitation in patients with a bilateral upper-limb congenital transverse deficiency especially before and after upper limb transplantation and to development of the EMG based prostheses.

Hepatic modulation of insulin-induced gastric acid secretion and EMG activity in rats

1980 ◽  
Vol 238 (5) ◽  
pp. R346-R352 ◽  
Author(s):  
J. Granneman ◽  
M. I. Friedman
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Emg Activity ◽  
Glucose Levels ◽  
Hepatic Portal Vein ◽  
Inhibited Acid ◽  
Hepatic Portal ◽  
The Brain

Intravenous infusions of fructose, a hexose that does not cross the blood-brain barrier, suppressed insulin-induced gastric acid secretion and electromyographic (EMG) activity despite continuing hypoglycemia. Hepatic portal vein infusions of 0.15 M fructose inhibited acid output while the same concentration delivered via the jugular vein did not, suggesting a hepatic site of action of the hexose. Only infusions of fructose that began before onset of the insulin-induced gastric responses were effective, whereas glucose infusions, which elevated plasma glucose levels, readily reversed ongoing gastric activity. The suppressive effects of fructose on gastric activity were prevented by prior section of the hepatic branch of the vagus nerve. In contrast, hepatic vagotomy did not prevent suppression of gastric responses by infusions of glucose, a hexose utilized by both brain and liver. These results suggest that receptors in the brain may initiate and terminate insulin-induced gastric acid secretion and motor activity, whereas sensors in the liver may inhibit these responses.

Modulations in Respiratory and Laryngeal Activity Associated With Changes in Vocal Intensity During Speech

2000 ◽  
Vol 43 (4) ◽  
pp. 934-950 ◽  
Author(s):  
Eileen M. Finnegan ◽  
Erich S. Luschei ◽  
Henry T. Hoffman
Keyword(s):  
Muscle Activity ◽  
Airway Resistance ◽  
Sudden Change ◽  
Lower Airway ◽  
Emg Activity ◽  
Primary Role ◽  
Respiratory Drive ◽  
Tracheal Pressure ◽  
Vocal Intensity ◽  
Laryngeal Airway

We tested the hypothesis that different strategies are used to alter tracheal pressure (P t ) during sustained and transient increases in intensity. It has been suggested that the respiratory system plays the primary role in P t changes associated with alteration in overall intensity, whereas laryngeal adjustment is primary for transient change in P t related to emphasis. Tracheal pressure, obtained via tracheal puncture, airflow (U), and laryngeal electromyography from the thyroarytenoid muscle (TA EMG) were collected from 6 subjects during sentence production at different intensity levels and with various stress patterns. Using a technique described in a previous study, we computed lower airway resistance (R law ) from measures of P t and U obtained during a sudden change in upper airway resistance. We used this resistance value, together with direct measures of P t and U during speech, to derive a time-varying measure of alveolar pressure (P a ), the pressure created by respiratory muscle activity and elastic recoil of the lungs. P a provided a measure of respiratory drive that was unaffected by laryngeal activity. Laryngeal airway resistance (R lx ) and TA EMG provided measures of laryngeal activity. The results of this study indicated that, contrary to the outcome predicted by the hypothesis, there was no difference in the strategies used to alter P t during sustained and transient increases in intensity. Although changes in both P a and R lx contributed to increase in P t , the contribution of P a was substantially greater. On average, P a contributed to 94% and R lx to 6% of the increase in P t associated with vocal intensity. A secondary purpose of the study was to determine the extent to which laryngeal muscle activity was related to R lx during speech. We found TA EMG activity increased with intensity but was not well correlated with R lx , suggesting that when it contracts, the TA muscle may affect intensity by loosening the cover, which allows for greater amplitude of vocal fold vibration, without necessarily increasing laryngeal airway resistance.

Decreased energy metabolism in brain stem during central respiratory depression in response to hypoxia

1996 ◽  
Vol 81 (4) ◽  
pp. 1772-1777 ◽  
Author(s):  
J. C. Lamanna ◽  
M. A. Haxhiu ◽  
K. L. Kutina-Nelson ◽  
S. Pundik ◽  
B. Erokwu ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Brain Stem ◽  
Respiratory Depression ◽  
Intracellular Ph ◽  
Metabolic Changes ◽  
Nucleus Ambiguus ◽  
Electromyographic Activity ◽  
Respiratory Drive ◽  
Energy Deficiency ◽  
The Brain

LaManna, J. C., M. A. Haxhiu, K. L. Kutina-Nelson, S. Pundik, B. Erokwu, E. R. Yeh, W. D. Lust, and N. S. Cherniack.Decreased energy metabolism in brain stem during central respiratory depression in response to hypoxia. J. Appl. Physiol. 81(4): 1772–1777, 1996.—Metabolic changes in the brain stem were measured at the time when oxygen deprivation-induced respiratory depression occurred. Eucapnic ventilation with 8% oxygen in vagotomized urethan-anesthetized rats resulted in cessation of respiratory drive, monitored by recording diaphragm electromyographic activity, on average within 11 min (range 5–27 min), presumably via central depressant mechanisms. At that time, the brain stems were frozen in situ for metabolic analyses. By using 20-μm lyophilized sections from frozen-fixed brain stem, microregional analyses of ATP, phosphocreatine, lactate, and intracellular pH were made from 1) the ventral portion of the nucleus gigantocellularis and the parapyramidal nucleus; 2) the compact and ventral portions of the nucleus ambiguus; 3) midline neurons; 4) nucleus tractus solitarii; and 5) the spinal trigeminal nucleus. At the time of respiratory depression, lactate was elevated threefold in all regions. Both ATP and phosphocreatine were decreased to 50 and 25% of control, respectively. Intracellular pH was more acidic by 0.2–0.4 unit in these regions but was relatively preserved in the chemosensitive regions near the ventral and dorsal medullary surfaces. These results show that hypoxia-induced respiratory depression was accompanied by metabolic changes within brain stem regions involved in respiratory and cardiovascular control. Thus it appears that there was significant energy deficiency in the brain stem after hypoxia-induced respiratory depression had occurred.

Rapid brain cooling in diving ducks

1998 ◽  
Vol 275 (2) ◽  
pp. R363-R371
Author(s):  
Michał Caputa ◽  
Lars Folkow ◽  
Arnoldus Schytte Blix
Keyword(s):  
Cold Water ◽  
Buccal Cavity ◽  
Recovery Period ◽  
Brain Cooling ◽  
Selective Brain Cooling ◽  
Diving Ducks ◽  
Pekin Ducks ◽  
Hypoxic Brain ◽  
The Brain ◽  
Crushed Ice

Hypothermia may limit asphyxic damages to the brain, and many small homeotherms have been shown to use anapyrexic strategies when exposed to asphyxic conditions. Larger homeotherms do not seem to use the same strategy, but could save oxygen and prevent hypoxic brain damage by employing selective brain cooling (SBC) in connection with asphyxia. To test the hypothesis that selective brain cooling may take place in connection with asphyxia, we have recorded brain [hypothalamic (THyp)] and body [colonic (TC)] temperatures and heart rates in four Pekin ducks during 5-min simulated (head submersion) diving in cold water (10°C). Diving resulted in a drop in THyp (3.1 ± 1.4°C) that continued into the recovery period ( P < 0.001). Restricting heat loss from the buccal cavity and eyes during diving compromised brain cooling in an additive manner. TC was not influenced by diving. Control cooling of the head with crushed ice during a 5-min period of undisturbed breathing had no effect on THyp. Warm water (35°C) markedly reduced brain cooling, and dive capacity was reduced by ∼14% ( P < 0.05) compared with diving in water at 10°C. The data suggest that SBC is used in ducks during diving, and we propose that this mechanism may enable the bird to save oxygen for prolonged aerobic submergence and to protect the brain from asphyxic damages.

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