Motor Activity Monitoring Research Articles

Acute and delayed effects of diisopropyl fluorophosphate on body temperature, heart rate, and motor activity in the awake, unrestrained rat.

Acute exposure to diisopropyl fluorophosphate (DFP) causes irreversible inhibition of acetylcholinesterase activity, leading to various behavioral and autonomic sequelae including hypothermia, reduced motor activity, and other neurological dysfunctions. To characterize the acute response and recovery of autonomic and behavioral processes to DFP exposure, rats of the Long-Evans strain were implanted with radiotransmitters that allowed the monitoring of core temperature, heart rate, and motor activity in unrestrained animals 24 h/d. These parameters were monitored for 96 h following subcutaneous injection of DFP at a dose of 0, 0.1, or 1.0 mg/kg. Rats given 0 and 0.1 mg/kg DFP displayed an increase in core temperature and motor activity during the first 24 h postinjection. The 1.0 mg/kg group showed a typical hypothermic response for the first 24 h following DFP administration. Core temperature decreased a maximum of 1.9 degrees C by 5 h after DFP and then started to recover, reaching control levels by 17 h after DFP treatment. Motor activity was also depressed during the first 24-h period in the 1.0 mg/kg group. Heart rate was initially elevated above basal levels in all treatment groups for several hours after treatment, but the 1.0 mg/kg group showed a decrease in heart rate at the time when core temperature began its recovery from hypothermia. Core temperature was the only parameter significantly affected by DFP during the 24-96 h recovery phase. The 0.1 and 1.0 mg/kg groups showed a significant elevation in core temperature for the 3 d after DFP administration. The elevation in core temperature during the recovery from DFP treatment may represent an important facet of the acute cholinergic neurotoxicity of organophosphate compounds.

An Animal Model for Delirium

This study describes an animal model for delirium comparing rats treated with either saline or atropine. The model was defined by recordings of cortical EEGs, maze performance, and behavioral observations. EEG slowing and increased amplitude, difficulty with attention and memory, sleep-wake cycle reversal, and changes in behavior (lack of focused direction, irritability, fluctuating levels of activity, excessive random sniffing) appeared consistent with signs and symptoms seen in human delirium. EEG abnormalities in atropine-treated rats returned to normal before cognitive deficits did. Motor activity monitoring did not reveal diminished motor activity as a confounding variable in maze performance.

Prolonged ambulatory monitoring of colonic motor activity in the pig.

The aim of this study was to develop a chronic model suitable for repeated, long-term studies of the interaction of behavior and colonic function in unrestrained pigs. Cecostomies were created in three 20-30 kg micropigs under general anesthesia. Fistulas were created by suturing the bowel to the abdominal wall. Recordings were made by passing a small (8F) solid-state pressure transducer through the fistula into the proximal bowel and connecting it to a battery-operated data logger worn in a vest on the pig's back. Cecostomies have remained patent and trouble-free for over 18 months. No serious infections have occurred. Preliminary data from a total of thirteen 24-h recording sessions showed 54% of all contractile activity to be in the 2-4 cpm frequency range. Increased motility was seen following meals and upon morning awakening. Motility was minimal during the night. Infrequent (10.31 +/- 2.05/24 h; mean +/- SD) propagated contractions were also noted. These contractions were generally of low amplitude (33.24 +/- 3.81 mmHg). These techniques allow prolonged, intraluminal recordings to be made from the colon of the unrestrained pig.

The delayed sleep phase syndrome: clinical and investigative findings in 14 subjects.

Fourteen subjects are described in whom a clinical diagnosis of the delayed sleep phase syndrome was made. The condition is multi-factorial, dependent on lifestyle, mood and personality, as well as on familial factors but no single factor in isolation is sufficient to explain the delay in sleep timing. Refusal to attend school may be important in some instances but will not explain cases with delayed age of onset. In half the subjects the delay in sleep phase started in childhood or adolescence. The syndrome causes severe disruption to education, work and family life. Polysomnography, motor activity monitoring of rest-activity cycles, plasma melatonin profiles and urinary melatonin metabolite excretion are normal. Different patterns of sleep phase delay seen in the syndrome include stable, progressive, irregular and non-24 hour sleep-wake cycles. These patterns may result from different social and other Zeitgebers ("time-markers", for example sunrise, sunset) in the normal environment. Treatment by forced sleep-wake phase advance or with melatonin resulted in a partial sleep-phase advance but this was not maintained on stopping treatment.

Twenty-four-hour monitoring of heart rate, motor activity and smoking behavior including comparisons between smokers and nonsmokers

The present study was an attempt to monitor continuously and in parallel cigarette consumption, heart rate, and physical activity under field conditions. In a first experiment the test-retest reliability of the recording devices was evaluated with a small number of nonsmoking students on days with similar schedules. The intraday development of heart rate and activity revealed a remarkable intraindividual stability, and the test-retest reliability coefficients calculated between the totals of heart rate and activity revealed values of 0.73 and higher for heart rate and 0.47 and higher for activity on comparable days. The second experiment was done with housewives as subjects to see whether heart rate and/or activity might differentiate smokers from nonsmokers in subjects who are less strictly bound to a fixed daily work program. The smoker/nonsmoker comparisons revealed significantly higher heart rates for smokers but almost identical activity readings. In a third experiment it was tested whether partial smoking abstinence in the morning might differentiate the morning and afternoon heart rates in smokers. Heart rate but not activity was significantly decreased during the abstinence period. Taken together, the simultaneous monitoring of heart rate and activity might be a valuable instrument in smoking research, since it is sensitive enough to detect manipulations of the smoking behavior under natural conditions.

A new model for the chronic monitoring of colonic motor activity in the pig

A new model for the chronic monitoring of colonic motor activity in the pig

Prolonged Ambulant Recordings of Small Bowel Motility Demonstrate Abnormalities in the Irritable Bowel Syndrome

Continuous 72-h recordings of duodenojejunal contractile activity were obtained from 20 freely ambulant subjects; pressure was detected by two strain-gauge sensors incorporated in a transnasal catheter attached to an encoder and a miniature tape recorder. The subjects were 12 patients with irritable bowel syndrome, 6 of whom were constipation predominant and 6 of whom were diarrhea predominant, and 8 healthy controls. The procedure was well tolerated by all subjects and did not interfere with sleep or normal activity. In all subjects, the diurnal migrating motor complex cycle was characterized by a brief phase 1 and a prolonged phase 2; this was reversed during sleep when phase 2 was virtually absent. All subjects showed a circadian variation in migrating motor complex propagation velocity, and there was no difference in the patterns of motor activity during sleep between any of the groups. During the day, the duration of postprandial motor activity was shorter in irritable bowel syndrome patients than in controls, and diurnal migrating motor complex intervals were shorter in diarrhea-predominant than in constipation-predominant irritable bowel syndrome. In 11 of 12 inflammatory bowel syndrome patients, episodes of clustered contractions recurring at 0.9-min intervals were noted; these episodes had a mean duration of 46 min and were often associated with transient abdominal pain and discomfort. In both groups of irritable bowel syndrome patients, defecation was significantly (p less than 0.01) prolonged with a greater number of voluntary abdominal contractions (p less than 0.01) than in controls. Prolonged ambulant monitoring of proximal bowel motor activity in subjects who are free to move, eat, and sleep as they choose has, for the first time, clearly defined the striking difference in motility between the sleeping and waking state and shown that abnormalities associated with irritable bowel syndrome are confined to the latter.

Quantitative analysis of rat activity in the home cage by infrared monitoring. Application to the acute toxicity testing of acetanilide and phenylmercuric acetate.

A new method for continuous in-cage monitoring of the activity of rats using passive sensors to detect the animals' infrared emissions, and its usefulness for toxicological screening tests is described. In order to obtain baseline values for toxicological tests, the differences between day and night activity, adaptation to changing day/night rhythm, the effects of handling the animals (measurement of body weight, food and water consumption) and the effect on activity patterns of the female estrus cycle were investigated. In two separate experiments, single doses of acetanilide and phenylmercuric acetate were administered. Passive infrared monitoring of motor activity proved to be a sensitive and discriminating method suitable for quantitative and qualitative assessment of acute toxic effects.

Monitoring of long-term motor activity in depressed patients.

Wrist motor activity was continuously recorded by a solid-state monitor in 12 patients with major depression throughout their stay in hospital; their clinical state was evaluated using three scales. During the day, activity troughs and immobility peaks occurred before noon and around 1500 hrs. Activity level progressively increased, while the duration of immobility decreased, with clinical improvement. The immobility measurement appeared to be a valuable index of depression and is more sensitive than the activity level, mainly for agitated depressed patients. Immobility episodes during the day could suggest the release of an ultradian sleep-wake rhythm in depression.

Some behavioral factors related to the effects of cold-restraint stress in rats: A factor analytic—multiple regression approach

Recently, some individual differences in rats have been shown to be related to stress-induced physiological responses. As yet there has been no attempt to incorporate measurement techniques from the psychometric field to this line of research. The present study was conducted to examine the utility of applying such methods to animal research. Physiological responses to cold-restraint stress in 26 male rats were investigated using a factor analytic-multiple regression procedure. Nineteen behavioral and physiological measures obtained during open-field testing, motor activity monitoring, and passive avoidance learning were subjected to a principle components factor analysis. Five factors were extracted which reflected exploratory behavior, general activity level, metabolic rate, behavioral reactivity, and autonomic reactivity. The obtained factor scores were used to predict physiological responses to four hours of supine cold-restraint using a step-wise multiple regression procedure. General activity level was the best predictor of adrenal weight and temperature loss. Autonomic reactivity was the best predictor of ulcer incidence and severity. Applications of these statistical procedures are discussed.

Detection of homovanillic acid in vivo using microcomputer-controlled voltammetry: Simultaneous monitoring of rat motor activity and striatal dopamine release

Linear sweep voltammograms recorded with carbon paste electrodes in the striatum of the unanaesthetised, unrestrained rat show three separate peaks. The effect on peak 3 of either unilateral homovanillic acid which are predicted by their effects on dopamine release. Simultaneous monitoring of total motor activity and homovanillic acid show significant correlation between these two parameters. The usefulness of this technique for monitoring dopamine release is critically evaluated in the light of these results.

Increased sensitivity to intracerebroventricular infusion of serotonin and deaminated indoles after lesioning rat with dihydroxytryptamine

Rats were prepared with a chronic intracerebroventricular cannula, and treated with intracisternal 5,7-dihydroxytryptamine (DHT) after i.p. desmethylimipramine or control vehicle. After recovery, they were tested behaviorally by direct observation and electronic monitoring of motor activity. Intraventricular infusion of a placebo or 5-hydroxyindoleacetic acid (5-HIAA) had little effect, but serotonin (5-HT) decreased, and norepinephrine increased locomotor activity in intact rats. Following pretreatment with 5,7-DHT, a small increase in locomotor activity was noted which was not altered by intracranial infusion of vehicle. In contrast, infusions of 5-HT produced a striking dose-dependent (ED50 = 5 micrograms/min) pattern of hyperactivity, 'myoclonic' jerking movements, postural changes, and autonomic responses. Norepinephrine increased locomotor activity in the DHT-lesioned rats (but not significantly more than in controls), but failed to produce the myoclonic syndrome. The deaminated indoles, indoleacetaldehyde and 5-HIAA were more potent than 5-HT in producing the myoclonic response; tryptamine when infused at an equimolar dose had no effect. The putative serotonin antagonists, cyproheptadine and methiothepin (i.p.), were more effective in blocking responses to infused 5-HT than to equipotent doses of deaminated indoles. These behavioral responses may represent exaggerated ex"itatory effects mediated by serotonin in the brain stem and spinal cord, possibly modified by altered forebrain mechanisms. A neurophysiologic or neuropharmacologic role for deminated indoles should be reconsidered as they may not merely be inactive metabolites.

VISUAL OBSERVATION AND ELECTRONIC MONITORING OF MOTOR ACTIVITY IN NEWBORN INFANTS

The spontaneous motor activity of newborn infants was electronically monitored using a sensing unit, placed in the bed or incubator. The sensor is an inductive-capacitive circuit, which allows monitoring of motor activity without attachment of cables or electrodes to the infant. The signal from the instrument and the coded visual observation of the motor activity was simultaneously transferred to a tape recorder. In a few cases the motor activity of the infant was also filmed. The correlation between the visual observations and the electronic records of motor activity was analyzed. The signals from the sensing unit are synchrone to the observed moments. The instrument presents a semiquantitative display of the motor activity pettern, and is superior to a method based on ordinary visual observation, which is inaccurate in prolonged studies. Different patterns of motor activity in newborn infants will be described and the application of motor activity studies in pediatric research and clinical work will be discussed.