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PubMed1981

Volition, performance of a boring task and time estimation.

Subjective intervals were obtained from 40 subjects (20 males, 20 females) who were assigned to a group with or without volition in which choice regarding task involvement was varied. Orthogonal to volition, half the subjects engaged in a boring task, half in an interesting task. Subjects assigned to the group with no volition displayed typical temporal behavior (an interesting task was judged as significantly shorter), while subjects in the group with volition showed no difference in protensity as a function of task quality, yielding the predicted interaction.

Boredom↗
PubMed1993

[Changing from spontaneous to volitional regulation of respiration decreases dyspnea].

The objective of the investigation was to assess whether volitional control of respiration can influence the intensity of dyspnoea. In 17 volunteers the author assessed, using Borg's method, the intensity of dyspnoea during breathing with an added dead space of 600 ml and with a flow resistance. The experiments were made in two sessions. During the first session when the examined subjects breathed spontaneously the author recorded spirographically the respiratory volume during control ventilation and after inclusion of the dead space and resistance. During the second session the experimental subjects were asked to attempt to imitate during inclusion of the dead space and resistance, as closely as possible, the respiratory pattern from the first session. In both instances the author assessed the partial pressure of CO2 in the air at the end of the expiration (P(ET)CO2). During the first session the tested subjects evaluance the dyspnoea: it had an average grade of 5.9 +/- 1.9. Volitional regulation of breathing led not only to a significant decline of the sensation of dyspnoea to 3.4 +/- 1.5 points of Borg's scale but also to a decline of the CO2 partial pressure (on average by 0.4 kPa). The author selected therefore among the tested subjects only those who were able to imitate closely the respiratory pattern from the first session (they had the same P(ET)CO2 in both instances). Also in these 8 subjects the intensity of dyspnoea during volitional control of ventilation declined from 6.5 +/- 1.8 grade to 3.8 +/- 1.5 grade according to Borg. The change from spontaneous to volitional regulation of breathing thus reduced the intensity of dyspnoea.

Adult↗
PubMed1995

Neuropsychology of schizophrenia according to Kraepelin: disorders of volition and executive functioning.

Emil Kraepelin was the first to identify schizophrenia as a distinct disease in 1896. The purpose of this paper is to rediscover and reexamine the neuropsychology of schizophrenia according to Kraepelin. Kraepelin thought that the "dementia" of dementia praecox was primarily a disorder of volition, rather than one of intellect. "Volition" or "will" referred to the ability to make conscious decisions and to carry them out. By quoting relevant passages in his classic textbook, Dementia Praecox and Paraphrenia, the case is made that Kraepelin's detailed description of volitional deficits in patients with dementia praecox clearly documents impairments in executive functioning in schizophrenia patients during the preneuroleptic era. To a large extent, these deficits may be responsible for the "dementia" of dementia praecox and the "chronicity" of chronic schizophrenia. If this hypothesis is correct, the long-range prognosis of patients with schizophrenia may be considerably improved by treatment programs designed to facilitate executive functioning.

Affect↗
PubMed1998

Volitional control of homonymous hemianopsia: a single case study.

A 52-year-old woman suffered a posterior left hemisphere infarction involving the geniculo-striate system with right homonymous hemianopsia. Eighteen months after the stroke, we used perimetry and PET imaging of cerebral blood flow to demonstrate the patient's volitional control over the size of the scotoma. The volitional control could be eliminated with competing cognitive tasks. Significant increases in cerebral blood flow in contralateral medial prefrontal cortex, and in ipsilateral dorsolateral frontal convexity, temporoparietal and insular cortex were associated with volitional control of the visual field defect.

Brain↗
PubMed2001

[Motivation, volition, and ambivalence: A contribution to understanding of long-term impairments among schizophrenic patients].

Traditional concepts of avolition (Kraepelin) and ambivalence (Bleuler) among schizophrenic patients can be interpreted in the light of present ideas of motivation and volition. Accordingly schizophrenic patients are marked both by oppositional high hope and fear components of implicit motives and by the impairment of volitional selfregulation, which both are vulnerability factors. In an environment lacking stimuli the patients cannot surpass their ambivalence through volitional selfregulation and remain passive. In this study 61 schizophrenic patients are compared with a control group of 69 non-patients. As expected, the schizophrenic patients show significant higher fear components of the implicit affiliation, achievement, and power motives, as well as an increased hope component of the affiliation motive. The comparison of subgroups of schizophrenic patients with distinguishing symptoms reveals no differences, which supports the assumption of stable traits.

Chronic Disease↗
PubMed1998

Towards a functional neuroanatomy of conscious perception and its modulation by volition: implications of human auditory neuroimaging studies.

Conscious sensory perception and its modulation by volition are integral to human mental life. Functional neuroimaging techniques provide a direct means of identifying and characterizing in vivo the systems-level patterns of brain activity associated with such mental functions. In a series of positron emission tomography activation experiments, we and our colleagues have examined a range of normal and abnormal auditory states that, when contrasted, provide dissociations relevant to the question of the neural substrates of sensory awareness. These dissociations include sensory awareness in the presence and absence of external sensory stimuli, the transition from sensory unawareness to awareness (or vice versa) in the presence of sensory stimuli, and sensory awareness with and without volition. The auditory states studied include hallucinations, mental imagery, cortical deafness modulated by attention, and hearing modulated by sedation. The results of these studies highlight the distributed nature of the functional neuroanatomy that is sufficient, if not necessary, for sensory awareness. The probable roles of unimodal association (as compared with primary) cortices, heteromodal cortices, limbic/paralimbic regions and subcortical structures (such as the thalamus) are discussed. In addition, interactions between pre- and post-rolandic regions are examined in the context of top-down, volitional modulation of sensory awareness.

Auditory Perception↗
PubMed1991

Regional cerebral blood flow during volitional breathing in man.

1. Positron emission tomographic imaging of brain blood flow was used to identify areas of motor activation associated with volitional inspiration in six normal male subjects. 2. Scans were performed using intravenous infusion of H2(15)O during voluntary targeted breathing and positive pressure passive ventilation at the same level. 3. Regional increases in brain blood flow, due to active inspiration, were derived using a pixel by pixel comparison of images obtained during the voluntary and passive ventilation phases. 4. Pooling data from all subjects revealed statistically significant increases in blood flow bilaterally in the primary motor cortex (left, 5.4%; right, 4.3%), in the right pre-motor cortex (7.6%), in the supplementary motor area (SMA; 3.1%) and in the cerebellum (4.9%). 5. The site of increased neural activation in the motor cortex, associated with volitional inspiration, is consistent with an area which when stimulated, either directly during neurosurgery or transcranially with a magnetic stimulus, results in activation of the diaphragm. 6. The presence of additional sites of neural activation in the pre-motor cortex and SMA appears analogous to the results of studies on voluntary limb movement. The site of the increase in the SMA was posterior to that previously reported for arm movements. These areas are believed to have a role 'upstream' of the motor cortex in the planning and organization of movement. 7. This technique provides a means of studying the volitional motor control of respiratory related tasks in man.

Adult↗
PubMed1996

Pharyngeal swallowing elicited by fluid infusion: role of volition and vallecular containment.

Nonalimentary swallows minimize aspiration by clearing accumulated fluid from the pharynx. This study aimed to define 1) the pharyngeal sensory field to elicit swallowing and 2) the effect of infusion rate, volition, taste, and temperature on pharyngeal swallows. Test solutions were directed into the valleculae at 6.5, 11.5, and 32 ml/min through a catheter in eight healthy volunteers. Deglutition was signaled with electromyography and electroglottography. Spatial distribution of infusate before swallowing was studied using videofluoroscopy coupled with a video timer. Volitional control was assessed with rapid or restrained swallows. Pharyngeal swallow latency decreased as the instillation rate increased, was potently modified with volition, and was unchanged by infusate taste or temperature. Water infusion into the valleculae did not trigger pharyngeal swallowing until liquids overflowed and reached the aryepiglottic folds or pyriform sinuses. The variation in swallow latency among flow rates was mainly due to the duration of liquid containment within the valleculae. This suggests that the valleculae act to contain pharyngeal secretions and residue and prevent aspiration by diverting their contents around the larynx before swallowing.

Adult↗
PubMed2002

Neck muscle responses to stimulation of monkey superior colliculus. II. Gaze shift initiation and volitional head movements.

We report neck muscle activity and head movements evoked by electrical stimulation of the superior colliculus (SC) in head-unrestrained monkeys. Recording neck electromyography (EMG) circumvents complications arising from the head's inertia and the kinetics of muscle force generation and allows precise assessment of the neuromuscular drive to the head plant. This study served two main purposes. First, we sought to test the predictions made in the companion paper of a parallel drive from the SC onto neck muscles. Low-current, long-duration stimulation evoked both neck EMG responses and head movements either without or prior to gaze shifts, testifying to a SC drive to neck muscles that is independent of gaze-shift initiation. However, gaze-shift initiation was linked to a transient additional EMG response and head acceleration, confirming the presence of a SC drive to neck muscles that is dependent on gaze-shift initiation. We forward a conceptual neural architecture and suggest that this parallel drive provides the oculomotor system with the flexibility to orient the eyes and head independently or together, depending on the behavioral context. Second, we compared the EMG responses evoked by SC stimulation to those that accompanied volitional head movements. We found characteristic features in the underlying pattern of evoked neck EMG that were not observed during volitional head movements in spite of the seemingly natural kinematics of evoked head movements. These features included reciprocal patterning of EMG activity on the agonist and antagonist muscles during stimulation, a poststimulation increase in the activity of antagonist muscles, and synchronously evoked responses on agonist and antagonist muscles regardless of initial horizontal head position. These results demonstrate that the electrically evoked SC drive to the head cannot be considered as a neural replicate of the SC drive during volitional head movements and place important new constraints on the interpretation of electrically evoked head movements.

Animals↗
PubMed2001

Development of muscle fatigue assessed by using superposition of evoked and volitional myoelectric potentials.

We studied muscle fatigue development using evoked myoelectrical potentials superimposed on volitional ones. The instantaneous frequency of superim posed M-waves and mean power frequencies of volitional electromyography (EMG) declined during sustained contraction, indicating that fatigue progressed. We divided fatigue into 3 phases, with 20 frames in each fatigue phase, corresponding to one-third of the total sample. The instantaneous frequency of superimposed M-waves and mean power frequencies of volitional EMG were correlated during early intensive isometric voluntary contractions and became increasingly uncorrelated as contraction proceeded. The coefficient between the mean power frequency and instantaneous frequency correlation was also greater at the first peak than at the second peak of the superimposed M-wave, indicating that the motor unit action potential was distorted. Distortion in the motor unit action potential shape depends on elongation of the depolarization zone of muscle fiber, because the superimposed M-wave is a peripheral indicator elicited by electrical stimulation. These results suggest that muscle fatigue develops based on the reduction of the conduction velocity of muscle fiber and on the elongation of the depolarization zone of muscle fiber.

Adult↗
PubMed1986

The relationships between volition, activity pattern, and life satisfaction in the elderly.

This study examines the relationships between the volition subsystem, activity pattern, and life satisfaction of 60 elderly individuals. The volition subsystem includes an individual's interests, values, and personal causation. The Occupational Questionnaire (OQ) was developed to measure volition subsystems and activity patterns, and it was pilot tested for reliability and validity. Scores on the OQ were compared with measures of subjects' life satisfaction. Results of the study identified several aspects of the subjects' occupations that were related to their level of life satisfaction. The most important findings were the positive correlations between the degree of interest, value, and personal causation in occupation and life satisfaction. Time spent in work and leisure was found to be correlated more highly with high levels of life satisfaction than was time spent in daily living tasks and rest. Although further verification of these results is needed, these findings indicate that occupational therapists may enhance the life satisfaction of their elderly patients by emphasizing interests, values, personal causation, work, and leisure in their treatment programs.

Aged↗
PubMed1994

Volition as narrative: understanding motivation in chronic illness.

This paper expands the current concept of volition in the Model of Human Occupation. The present version views personal causation, values, and interests as traits that determine choices to engage in occupations. Through a detailed investigation of the life histories of two persons with psychiatric disorders, this paper illustrates how volition is embedded in a personal narrative. Two features of narratively organized volition are highlighted: (a) how narrative places decisions and actions within a plot, thus giving them meaning in the context of a whole life, and (b) how the personal narrative motivates the person by serving as a context for choosing and action. Thus, the paper illustrates how persons seek to narrate their lives and live their life narratives.

Chronic Disease↗
PubMed2004

Dissociating the spatio-temporal characteristics of cortical neuronal activity associated with human volitional swallowing in the healthy adult brain.

Human swallowing represents a complex highly coordinated sensorimotor function whose functional neuroanatomy remains incompletely understood. Specifically, previous studies have failed to delineate the temporo-spatial sequence of those cerebral loci active during the differing phases of swallowing. We therefore sought to define the temporal characteristics of cortical activity associated with human swallowing behaviour using a novel application of magnetoencephalography (MEG). In healthy volunteers (n = 8, aged 28-45), 151-channel whole cortex MEG was recorded during the conditions of oral water infusion, volitional wet swallowing (5 ml bolus), tongue thrust or rest. Each condition lasted for 5 s and was repeated 20 times. Synthetic aperture magnetometry (SAM) analysis was performed on each active epoch and compared to rest. Temporal sequencing of brain activations utilised time-frequency wavelet plots of regions selected using virtual electrodes. Following SAM analysis, water infusion preferentially activated the caudolateral sensorimotor cortex, whereas during volitional swallowing and tongue movement, the superior sensorimotor cortex was more strongly active. Time-frequency wavelet analysis indicated that sensory input from the tongue simultaneously activated caudolateral sensorimotor and primary gustatory cortex, which appeared to prime the superior sensory and motor cortical areas, involved in the volitional phase of swallowing. Our data support the existence of a temporal synchrony across the whole cortical swallowing network, with sensory input from the tongue being critical. Thus, the ability to non-invasively image this network, with intra-individual and high temporal resolution, provides new insights into the brain processing of human swallowing.

Adult↗
PubMed1999

Functional MRI localisation of central nervous system regions associated with volitional inspiration in humans.

1. Functional magnetic resonance imaging (fMRI) provides a means of studying neuronal circuits that control respiratory muscles in humans with better spatial and temporal resolution than in previous positron emission tomography (PET) studies. 2. Whole brain blood oxygenation level-dependent (BOLD) changes determined by fMRI were used to identify areas of neuronal activation associated with volitional inspiration in five healthy men. Four series of scans of each subject were acquired during voluntary breathing (active task) and mechanical ventilation (passive task). Ventilation and end-tidal PCO2 were similar between tasks. Scan data were re-aligned to correct for movement artefacts and cross-referenced breath by breath to respiratory data for selective averaging of inspiratory and expiratory images. 3. Group analysis identified significant increases in the fMRI signal with volitional inspiration in the superior motor cortex, premotor cortex and supplementary motor area at loci similar to those detected in earlier studies that used PET. Additional regions activated by volitional inspiration included inferolateral sensorimotor cortex, prefrontal cortex and striatum (these foci were only revealed by PET under significant inspiratory load). 4. This study represents the first synchronised breath-by-breath analysis of respiratory-related neuronal activity with whole brain imaging in humans. Temporal resolution is sufficient to distinguish individual breaths at a normal breathing frequency.

Adult↗
PubMedDate not supplied

Head-only rotational testing: influence of volition and vision.

Head-only rotational testing has been suggested as a method of assessing the vestibuloocular reflex in patients with reduced vestibular function as a result of ototoxicity. The purpose of this study was to investigate the influence of vision and volition on horizontal vestibuloocular reflex responses during head-only rotation in normal subjects to better define the test parameters for future clinical application. Ten asymptomatic, healthy subjects were tested using various combinations of volitional and visual conditions during head-only rotation. Results indicated that visual fixation enhanced responses slightly and that response dynamics were altered somewhat by volition. These findings provide motivation for future studies to further define head-only rotation test parameters for patients with suspected vestibular abnormalities.

Adult↗
PubMed1999

Ultrastructural change at rat cerebellothalamic synapses associated with volitional motor adaptation.

Our ability to develop or modify motor skills is thought to involve persistent changes in the efficacy of synaptic transmission (synaptic plasticity) in the cerebellum. Previous work from our laboratory and others, examining synapses between neurons in the deep cerebellar nuclei and neurons in the thalamus revealed ultrastructural characteristics that have been implicated in the expression of synaptic plasticity at other locations in the brain. The present study sought evidence of ultrastructural plasticity at cerebellothalamic synapses associated with volitional motor adaptation. Adult rats were subject to 21 days of training, throughout which a novel load (overcome by predominantly shoulder adduction) was applied to the left forelimb while they fed (the right forelimb acted as an internal control). The behavioral paradigm was observed to produce a profound unilateral motor adaptation that was complete by day 15. Three days before the end of training, intracortical microstimulation was performed to identify the regions of primary motor cortex responsible for execution of shoulder adduction movements on the experimental (right) and control (left) sides of the brain. A retrograde neuronal tracer was injected into these cortical regions and the animals were returned to the training cage. Following training, small blocks of thalamic tissue containing retrogradely labeled cells were removed from the brains for ultrastructural analyses of presumed cerebellothalamic synapses (see Materials and Methods section). The only ultrastructural change observed to occur in association with the volitional motor adaptation was an increase in the proportion of dendritic shaft active zone with docked synaptic vesicles.

Adaptation, Physiological↗
PubMed2005

Decrement of the skin conductance response to repeated volitional inspiration.

OBJECTIVE: To examine response decrement of the recently reported inspiratory skin conductance response (SCR) [Lim CL, Seto-Poon M, Clouston PD, Morris JG. Sudomotor nerve conduction velocity and central processing time of the skin conductance response. Clin Neurophysiol 2003;114:2172-80]. METHODS: Twelve healthy adult volunteers performed 3 tasks (A) a control task of maintaining tidal breathing and then two randomized tasks, (B) a deep inspiration to a target oral pressure and (C) tapping with a finger. Each task was performed 30 times on cue every 20s in 3 runs with 5 min of rest between runs. The SCR, oral pressure, airflow, inspired volume and cue signal were recorded continuously and analysed offline. SCR amplitude was logarithmically transformed and then statistically analysed, using a linear mixed effects model, as a function of run number, trial number and absolute error between target and actual oral pressures. RESULTS: Inspiratory efforts elicited exponentially decreasing SCR amplitude with increasing trial number during each run (P < 0.0001). After adjusting for trial number, the mean SCR amplitude of the second and the third run were, respectively, 24.2 (95% CI (0.175, 0.336), P < 0.001) and 14.4% (95% CI (0.104, 0.200), P < 0.001) of the first run amplitude. CONCLUSIONS: Volitional deep inspiration reliably activates an SCR that exhibits response decrement with repetition, which may be habituation. SIGNIFICANCE: The volitional inspiratory SCR may assist in the assessment of sympathetic autonomic status in patients with peripheral afferent neuropathy.

Adult↗
PubMed2005

Volition and conflict in human medial frontal cortex.

Controversy surrounds the role of human medial frontal cortex in controlling actions. Although damage to this area leads to severe difficulties in spontaneously initiating actions, the precise mechanisms underlying such "volitional" deficits remain to be established. Previous studies have implicated the medial frontal cortex in conflict monitoring and the control of voluntary action, suggesting that these key processes are functionally related or share neural substrates. Here, we combine a novel behavioral paradigm with functional imaging of the oculomotor system to reveal, for the first time, a functional subdivision of the pre-supplementary motor area (pre-SMA) into anatomically distinct areas that respond exclusively to either volition or conflict. We also demonstrate that activity in the supplementary eye field (SEF) distinguishes between success and failure in changing voluntary action plans during conflict, suggesting a role for the SEF in implementing the resolution of conflicting actions. We propose a functional architecture of human medial frontal cortex that incorporates the generation of action plans and the resolution of conflict.

Adult↗