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At least 217 records · Page 12Linked to original sources
PubMed1975

Timing of activity in cerebellar dentate nucleus and cerebral motor cortex during prompt volitional movement.

The discharge of neurons in cerebellar dentate nucleus and cerebral motor cortex was recorded on alternate days in each of 3 monkeys in association with prompt arm movement in response to a light signal. The time of change of the discharge of each neuron in relation to arm movement was computed. The distributions of the time of change for cerebellum and cerebrum overlapped, but the cerebellar distribution was shifted slightly earlier.

Animals↗
PubMed1987

Application of computer averaging techniques to the study of learned volitive heartbeat control.

Research on the acquisition of conscious cardiovascular control (Yellin 1984, 1986) utilized computer averaging of electrocardiographic (ECG) cycles to demonstrate and document precise, reliable and sustainable time-locking of heartbeat to external stimuli on demand. ECG cycles were treated as evoked responses, and successive epochs were summated, beginning with Zeitgeber-stimulus (ZS) onset, and with the duration of each epoch equaling the ZS's interstimulus interval. Cardiac synchrony was exhibited by event-modulated (time-locked) cardiac responses (EMCRs) and in average ECGs.

Biofeedback, Psychology↗
PubMed1995

Tomato juice, chocolate drink, and other fluids suppress volitional drinking of alcohol in the female Syrian golden hamster.

Although the hamster generally prefers alcohol at a level similar to that of the rat or mouse selectively bred to consume alcohol, the drinking hamster demonstrates neither physical dependence on alcohol nor elevated blood levels of alcohol, which are two typical criteria characterizing an animal model of alcoholism. The present investigation was designed to determine whether a third criterion of an animal model (i.e., consumption of high levels of alcohol in the presence of a palatable fluid, fulfilled by the P rat) would be met by the female Syrian golden hamster (Mesocricetus auratus). A standard 3-bottle preference test was undertaken in 6 female hamsters over an 11 day period, in which water was presented in one tube and, in a second tube, a v/v solution of alcohol which was increased in concentration from 3% to 50% on each day as follows: 3%, 5%, 7%, 9%, 12%, 15%, 20%, 25%, 30%, 40%, and 50%. Then each hamster was offered its individually determined, maximally preferred concentration of alcohol for 4-8 days, which was 20%, 25%, or 30% alcohol. The mean absolute intake of alcohol during this period was 17.9 +/- 1.1 g/kg per day, whereas the mean proportion of alcohol to total fluid was 0.68 +/- 0.05. Then over a 4-day interval, a solution of tomato juice, peach juice, mango juice, dextrose and a chocolate beverage (Ensure Plus), all made isocaloric to the alcohol solutions with dextrose, was placed in the third tube simultaneously with water and the individually preferred concentration of alcohol.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMedDate not supplied

Buspirone attenuates volitional alcohol intake in the chronically drinking monkey.

Four macaque monkeys which showed excessive preference for ethyl alcohol solutions in a self-selection paradigm were used as subjects. Earlier these animals had been given intracerebroventricular (ICV) injections of human cerebrospinal fluid, which produced pharmacologically significant effects on the animals' alcohol consumption. The purpose of the present investigation was to determine whether the parenteral administration of a new anxiolytic compound, buspirone, would alter the pattern of alcohol drinking already established in the monkey. Initially the maximally selected concentration of alcohol of 12% was determined on the basis of a standard ad lib alcohol-water preference screen. Each monkey was offered 12% alcohol and water for a basal pre-injection period of 4 days. Then, on each of the next three days, either the saline control vehicle or buspirone, 1.25, 5.0 or 20.0 mg/kg, was injected intramuscularly at 930 and 1630 hours. On these days, behavioral observations were recorded before and after buspirone's administration in order to evaluate the latency as well as recovery from the drug's effect. Subsequently, a four-day post-injection, 12% alcohol-water test was conducted. Although the saline control and 1.25 mg/kg dose of buspirone were without effect on alcohol intake, both the 5.0 and 20.0 mg/kg doses of buspirone attenuated significantly the consumption of alcohol by the monkeys. This reduction in terms of absolute g/kg as well as the proportion of alcohol to water ingested was approximately 30-60% of baseline intakes. Following buspirone treatment, the amount of alcohol consumed returned essentially to previously high levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aggression↗
PubMedDate not supplied

Volitional consumption of ethanol by fawn-hooded rats: effects of alternative solutions and drug treatments.

Behavioral and neurochemical measures of brain 5-hydroxytryptamine (5-HT) function in the Fawn-Hooded rat are abnormal relative to outbred strains of rats. Fawn-Hooded rats freely drink large amounts of 10% ethanol in the presence of water and have been proposed to be an animal model for studies related to alcoholism. In this study, Fawn-Hooded rats were given solutions of ethanol increasing in concentration from 3% to 30% (w/v in tap water) over 10 days with tap water in a second drinking tube and a third tube left empty. The solutions of ethanol that produced maximal drinking with a preference (ml ethanol/ml total fluid) near 50% ranged from 5% to 13%, which became the fixed individual concentrations for each rat. After a 5-day baseline period the rats were offered a solution in the third drinking tube of either 0.5% aspartame or chocolate Ultra SlimFast (diluted with water 2:1). The chocolate drink, but not aspartame, significantly reduced the consumption of alcohol by 73%. For the drug experiments, the rats were given successive 4-day periods of: baseline drinking; drug or saline injections b.i.d.; and a posttreatment period. Neither ipsapirone, a 5-HT1a partial agonist, nor naltrexone injected inhibited the intakes of ethanol solutions. Treatment with 2.5 mg/kg of amperozide, a 5-HT2 antagonist, decreased the consumption of ethanol by 38%, but also caused a decrease in consumption of food. These results show a pattern of drinking of increasing concentrations of ethanol different than other strains of rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMed2005

Head control: volitional aspects of rehabilitation training in patients with multiple sclerosis compared with healthy subjects.

OBJECTIVE: To investigate the role of voluntary mechanisms and motor learning in head stability and the impact of longitudinal biofeedback training in head control. DESIGN: Crossover trial and single-subject research design. SETTING: Neurorehabilitation research institute. PARTICIPANTS: Head stability during treadmill gait was measured in healthy subjects and patients with multiple sclerosis (MS). INTERVENTION: The experimental condition in which subjects walked on the treadmill was compared with that in which the head was voluntarily stabilized. In another experimental condition, augmented feedback of head displacement was provided by means of a laser mounted on the head that projected a laser beam on a screen. The motor learning was investigated with biofeedback training sessions. Positional feedback was represented by the laser beam, with subjects having to stabilize the beam while walking on the treadmill. MAIN OUTCOME MEASURE: Head angular oscillation in the sagittal and frontal planes. RESULTS: Results showed that on verbal request, healthy subjects and patients further stabilized the head during gait, especially in the sagittal plane. Short-term feedback of head displacement was no better than self-stabilization at improving head control. Conversely, the motor learning was evident in the rehabilitation protocol: after 10 to 15 training sessions, patients with MS showed a clinically relevant decrease of head angular oscillations. CONCLUSIONS: Voluntary mechanisms play a role in head stabilization during gait. Augmented biofeedback of head displacement may be effective in reducing head oscillations.

Adaptation, Physiological↗
PubMed2002

The role of expectancy and volition in smooth pursuit eye movements.

The most important factor allowing the generation of pursuit eye movements prior to target onset is confidence in the likelihood of imminent target appearance. We show how these anticipatory pursuit responses are essentially ballistic motor primitives and how the signal that drives them in normally defined by stored information concerning target speed, duration and direction. But we also show how static cues may be used to grade the level of these motor primitives 'on-line'. We further demonstrate that, when concatenated, these graded motor primitives can be rapidly combined to form predictive smooth movement trajectories in response to complex multi-ramp sequences.

Cues↗
PubMed2002

Control of volitional and reflexive saccades in Tourette's syndrome.

We hypothesized that Tourette's syndrome (TS) patients would display abnormal control of saccades because of overlap between brain areas suspected in TS pathophysiology and those involved saccade control. Subjects were required to look toward (pro-saccade) or away from (anti-saccade) a visual target. Saccadic reaction times were elevated among TS subjects in all tasks. The occurrence of reflexive pro-saccades in the immediate anti-saccade task was normal, suggesting that the ability to inhibit reflexive saccades was not impaired in TS. However, timing errors (eye movements made prior to GO signal in delayed saccade tasks) were increased in TS indicating that ability to inhibit or delay planned motor programs is significantly impaired in TS.

Adolescent↗
PubMed2003

Quadriceps strength and volitional activation before and after total knee arthroplasty for osteoarthritis.

INTRODUCTION: Patients with osteoarthritis (OA) of the knee have quadriceps weakness and arthrogenous muscle inhibition (AMI). While total knee arthroplasty (TKA) reliably reduces pain and improves function in patients with knee OA, quadriceps weakness persists after surgery. The purpose of this investigation was to assess contributions of AMI to quadriceps weakness before and after TKA and to assess the effect of pain on AMI. METHODS: Twenty-eight patients with unilateral, end-stage, primary knee OA were tested an average of 10 days before and 26 days after TKA. The mean age at time of operation was 63 years (range 49-82 years). Measurements on the involved and uninvolved knees were performed using the burst-superimposition technique, where supramaximal electrical stimulation is superimposed on a voluntary contraction. Knee pain during contraction was measured using a numeric rating scale. RESULTS: The involved quadriceps were significantly weaker than the uninvolved prior to TKA (p<0.05). Quadriceps strength decreased by 60% (p<0.001) and activation decreased 17% (p<0.001) after TKA. Changes in muscle activation accounted for 65% of the variability in the change in quadriceps strength (r(2)=0.65) (p<0.001). Knee pain during muscle contraction accounted for a small, but significant portion of the change in voluntary activation (r(2)=0.22) (p=0.006). DISCUSSION: Exercise regimens that emphasize strong muscle contraction and clinical tools that facilitate muscle activation like biofeedback and neuromuscular electrical stimulation may be necessary to reverse the quadriceps activation failure and weakness in the patients with knee OA that worsens after TKA. The failure of current rehabilitation regimens to directly address activation deficits within the first months after surgery may explain the persistent quadriceps weakness in patients after TKA.

Aged↗
PubMed1981

A physiological investigation of volitional and nonvolitional experience during posthypnotic amnesia.

Highly responsive hypnotic subjects, who were classified as having control over remembering (voluntaries) or not having control over remembering (involuntaries) during posthypnotic amnesia, were compared with each other on four physiological measures (heart rate, electrodermal response, respiration rate, muscle tension) during posthypnotic recall. Two contextual conditions were employed: One was meant to create pressure to breach posthypnotic amnesia (lie detector instructions); the other, a relax condition, served as a control. The recall data confirmed earlier findings of Howard and Coe and showed that voluntary subjects under the lie detector condition recalled more than the other three samples that did not differ from each other. However, using another measure of voluntariness showed that both voluntary and involuntary subjects breached under lie detector conditions. Electrodermal response supported the subjects' reports of control in this case. Physiological measures were otherwise insignificant. The results are discussed as they relate to (a) studies attempting to breach posthypnotic amnesia, (b) the voluntary/involuntary classification of subjects, and (c) theories of hypnosis.

Arousal↗
PubMed1985

Volitional experiences associated with breaching posthypnotic amnesia.

Highly responsive hypnotic subjects classified as having control over remembering (voluntaries) or not having control over remembering (involuntaries) during posthypnotic amnesia were compared during posthypnotic recall. Subjects rerated their voluntariness after the experiment. Two contextual conditions were employed (2 X 2 design): a lie detector condition meant to create pressure to breach amnesia and a relax control condition. In contrast to earlier findings, the recall data showed that both voluntary and involuntary subjects breached under the lie detector condition compared with their counterparts in the relax condition; however, the degree of breaching was not great in any condition. The results are discussed as they relate to studies attempting to breach posthypnotic amnesia and characteristics of the voluntary-involuntary dimension.

Amnesia↗