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At least 109 records · Page 6Linked to original sources
PubMed2004

A high resolution assessment of the repeatability of relative location and intensity of transcranial magnetic stimulation-induced and volitionally induced blood oxygen level-dependent response in the motor cortex.

OBJECTIVE: Using functional magnetic resonance imaging, we assessed variation in location and intensity of blood oxygen level-dependent contrast associated with movements induced by transcranial magnetic stimulation or volition. BACKGROUND: Anatomic location and within-subject repeatability of blood oxygen level-dependent responses induced by transcranial magnetic stimulation comprise critical information to the use of interleaved transcranial magnetic stimulation/functional magnetic resonance imaging as a neuroscience tool. METHODS: Eleven healthy adults were scanned 3 times each at 1.5 T. Interleaved with functional magnetic resonance imaging, 1-Hz transcranial magnetic stimulation was applied over motor cortex. VOL was alternated with transcranial magnetic stimulation over the scans. RESULTS: Intra-subject standard deviations in blood oxygen level-dependent locations ranged between 3 and 6 millimeters, allowing localization to subregions of the motor strip. Coil placement relative to blood oxygen level-dependent location varied more than blood oxygen level-dependent location (sdx = 9.5mm, sdy = 8.7 mm, sdz = 9.0mm) with consistent anterior displacement (dy = 21.8 mm, P = <0.025). Analysis of variance did not detect significant differences between transcranial magnetic stimulation and VOL blood oxygen level-dependent locations or intensities, in contrast to significant intensity differences detected in auditory blood oxygen level dependence. CONCLUSION: The high repeatability of location of transcranial magnetic stimulation-induced blood oxygen level-dependent activation suggests that transcranial magnetic stimulation/functional magnetic resonance imaging stimulation can be used as a precise tool in investigation of cortical mechanisms. The similarity between VOL and transcranial magnetic stimulation suggests that transcranial magnetic stimulation may act through natural brain movement circuits.

Adult↗
PubMed2006

Volition and imagery in neurorehabilitation.

New interventional approaches have been proposed in the last few years to treat the motor deficits resulting from brain lesions. Training protocols represent the gold-standard of these approaches. However, the degree of motor recovery experienced by most patients remains incomplete. It would be important to improve our understanding of the mechanisms underlying functional recovery. This chapter examines the role of two possible mechanisms that could operate to improve motor function in this setting: volition and motor imagery. It is argued that both represent possible strategies to enhance training effects.

Brain Injuries↗
PubMed2003

Role of primary sensorimotor cortex and supplementary motor area in volitional swallowing: a movement-related cortical potential study.

We investigated the role of the cerebral cortex, particularly the face/tongue area of the primary sensorimotor (SMI) cortex (face/tongue) and supplementary motor area (SMA), in volitional swallowing by recording movement-related cortical potentials (MRCPs). MRCPs with swallowing and tongue protrusion were recorded from scalp electrodes in eight normal right-handed subjects and from implanted subdural electrodes in six epilepsy patients. The experiment by scalp EEG in normal subjects revealed that premovement Bereitschaftspotentials (BP) activity for swallowing was largest at the vertex and lateralized to either hemisphere in the central area. The experiment by epicortical EEG in patients confirmed that face/tongue SMI and SMA were commonly involved in swallowing and tongue protrusion with overlapping distribution and interindividual variability. BP amplitude showed no difference between swallowing and tongue movements, either at face/tongue SMI or at SMA, whereas postmovement potential (PMP) was significantly larger in tongue protrusion than in swallowing only at face/tongue SMI. BP occurred earlier in swallowing than in tongue protrusion. Comparison between face/tongue SMI and SMA did not show any difference with regard to BP and PMP amplitude or BP onset time in either task. The preparatory role of the cerebral cortex in swallowing was similar to that in tongue movement, except for earlier activation in swallowing. Postmovement processing of swallowing was lesser than that of tongue movement in face/tongue SMI; probably suggesting that the cerebral cortex does not play a significant role in postmovement processing of swallowing. SMA plays a supplementary role to face/tongue SMI both in swallowing and tongue movements.

Adult↗
PubMed2005

Glycogenin activity and mRNA expression in response to volitional exhaustion in human skeletal muscle.

Glycogenolysis results in the selective catabolism of individual glycogen granules by glycogen phosphorylase. However, once the carbohydrate portion of the granule is metabolized, the fate of glycogenin, the protein primer of granule formation, is not known. To examine this, male subjects (n = 6) exercised to volitional exhaustion (Exh) on a cycle ergometer at 75% maximal O2 uptake. Muscle biopsies were obtained at rest, 30 min, and Exh (99 +/- 10 min). At rest, total glycogen concentration was 497 +/- 41 and declined to 378 +/- 51 mmol glucosyl units/kg dry wt following 30 min of exercise (P < 0.05). There were no significant changes in proglycogen, macroglycogen, glycogenin activity, or mRNA in this period (P > or = 0.05). Exh resulted in decreases in total glycogen, proglycogen, and macroglycogen as well as glycogenin activity (P < 0.05). These decrements were associated with a 1.9 +/- 0.4-fold increase in glycogenin mRNA over resting values (P < 0.05). Glycogenolysis in the initial exercise period (0-30 min) was not adequate to induce changes in glycogenin; however, later in exercise when concentration and granule number decreased further, decrements in glycogenin activity and increases in glycogenin mRNA were demonstrated. Results show that glycogenin becomes inactivated with glycogen catabolism and that this event coincides with an increase in glycogenin gene expression as exercise and glycogenolysis progress.

Adult↗
PubMed2001

Cerebral cortical representation of automatic and volitional swallowing in humans.

Although the cerebral cortex has been implicated in the control of swallowing, the functional organization of the human cortical swallowing representation has not been fully documented. Therefore, the present study determined the cortical representation of swallowing in fourteen healthy right-handed female subjects using single-event-related functional magnetic resonance imaging (fMRI). Subjects were scanned during three swallowing activation tasks: a naïve saliva swallow, a voluntary saliva swallow, and a water bolus swallow. Swallow-related laryngeal movement was recorded simultaneously from the output of a bellows positioned over the thyroid cartilage. Statistical maps were generated by computing the difference between the magnitude of the voxel time course during 1) a single swallowing trial and 2) the corresponding control period. Automatic and volitional swallowing produced activation within several common cortical regions, the most prominent and consistent being located within the lateral precentral gyrus, lateral postcentral gyrus, and right insula. Activation foci within the superior temporal gyrus, middle and inferior frontal gyri, and frontal operculum also were identified for all swallowing tasks. In contrast, activation of the caudal anterior cingulate cortex was significantly more likely in association with the voluntary saliva swallow and water bolus swallow than the naïve swallow. These findings support the view that, in addition to known brain stem areas, human swallowing is represented within a number of spatially and functionally distinct cortical loci which may participate differentially in the regulation of swallowing. Activation of the insula was significantly lateralized to the right hemisphere for the voluntary saliva swallow, suggesting a functional hemispheric dominance of the insula for the processing of swallowing.

Adult↗
PubMed2000

Loss of left-sided volitional movements caused by a combined lesion of the corpus callosum and right hemisphere:'initiation pseudohemiakinesia'.

We report a right-handed patient who showed a marked loss of unilateral volitional movements of the left limbs after the onset of a cerebral infarction in the combined territories of the right anterior and middle cerebral arteries. The same limbs retained their mobility in acts requiring bilateral sides of the body. This left-sided abnormal behavior resembled motor neglect resulting from lateralized brain damage. Behavioral and neuroradiological findings presented by this patient, however, suggested that callosal disconnection was definitely involved in this symptomatology. We postulate that in this patient, the diseased right hemisphere could no longer initiate movements of the left limbs despite its potential ability to realize them, and that the injured callosum prevented the intact left hemisphere from initiating unilateral voluntary movements of the left limbs. We suggest that this so far undescribed symptomatology be called 'initiation pseudohemiakinesia' in order to be distinguished from other rare forms of unilateral voluntary movements like motor neglect, extinction or directional hypokinesia.

Brain Diseases↗
PubMed2000

Volitional covert orienting to a peripheral cue does not suppress cue-induced inhibition of return.

Detection reaction time (RT) at an extrafoveal location can be increased by noninformative precues presented at that location or ipsilaterally to it. This cue-induced inhibition is called inhibition of return or ipsilateral inhibition. We measured detection RT to simple light targets at extrafoveal locations that could be designated for covert orienting by local or distant cues. We found that cue-induced inhibition cooccurred in an additive fashion with the direct effects of covert orienting, i.e., it detracted from facilitation at attended locations and increased the disadvantage for unattended locations. Thus, cue-induced inhibition cannot be suppressed by a volitional covert orienting to the cued location; the co-occurrence of different facilitatory and inhibitory effects confirms the simultaneous operation of multiple independent attentional mechanisms during covert orienting.

Adult↗
PubMed2003

Addiction: a disease of volition caused by a cognitive impairment.

The common etiology of substance and behavioural addictions is one that suggests faulty volition caused by a cognitive impairment. A cognitive impairment that minimizes the recall of the negative effects of the addictive behaviour is viewed as necessary and causal to all addictions. The proposed definition for addiction clarifies the confusion associated with addictive disorders, explains the many variable presentations, and provides an explanation of comorbidity and treatment outcomes. In addition, this paper suggests why this process has not been previously identified.

Attitude↗
PubMed1992

Localization of emotional and volitional facial paresis.

Emotional facial paresis is characterized by impaired activation of face muscles with emotion but normal voluntary activation. We report seven patients with this sign. Their lesions involved the frontal lobe white matter, the striatocapsular territory, the anterolateral thalamus and insula, the posterior thalamus and operculum, and the mesial temporal lobe and insula each in one patient, and the posterior thalamus in two patients. Volitional facial paresis affects facial movements with voluntary effort, sparing activation on emotion. We report four such patients, with lesions involving the motor cortex in one and the pyramidal tract in the cerebral hemisphere in three.

Adult↗
PubMed2002

Volition to action--an event-related fMRI study.

Current concepts of the anterior cingulate cortex (ACC) increasingly emphasize its role as an interface between limbic and neocortical functions. It has been pointed out that ACC activation reflects the intentional amount of effort (volition) that a subject uses in a task. In previous electrophysiological source localization investigations during a choice reaction task, we described a strong early activation in the ACC region approximately 120-150 ms after stimulus presentation. The degree of midline ACC activation correlated negatively with reaction time. This observation together with the finding that ACC activation precedes information processing in cortical association areas provided preliminary support to the notion that the extent of ACC activation is related to a subject's task engagement. However, due to the inverse problem and the relatively low spatial resolution of the electrophysiological measurements, we were not able to make inferences about the validity and the exact localization of the observed midline activation maximum. We addressed this question and performed an event-related fMRI study in six healthy volunteers during a visual choice reaction task. Two checkerboard stimuli were presented either in the left or right visual hemifield in randomized order and with an interstimulus interval requiring an appropriate motor response (left-right button press). A bilateral BOLD maximum was observed in the region of the supplementary motor area confluent with the neighboring motor area of the dorsal ACC. The degree of ACC activation correlated significantly with reaction time. These results are in line with our previous electrophysiological findings and provide further evidence that early ACC activation during a choice reaction task reflects the intentional effort of a subject to carry out a task.

Adult↗
PubMed1990

[Emotional-volitional training in the combined treatment of patients with rheumatoid arthritis].

The development of placebo effect was found to be related to the psychological status and neurophysiological features of the body. This made it possible to elaborate the disadaptation hypothesis of the disease development and a total systems approach to its treatment, characterized by the necessity of conducting both conventional (aimed at suppression of the autoimmune process and inflammation) and activation therapy. The method of emotional volitional training (EVT) designed by the authors is advanced as one of the components of the activation therapy lying in the use of music therapy, auto- and heteropsychic actions together with application of an optimal variety of group physical training. Application of the EVT to the treatment of 86 patients with rheumatoid arthritis enabled the drug dosage to be reduced by as many as 50%, to improve the patients' mental status and to enhance work fitness, promoting the decrease of the hospital treatment by 4-5 days and prolongation of the remission from 6 months to 1.5 years.

Adolescent↗
PubMed1988

The development of volitional behavior in the toddler years.

In order to generate a description of early volitional skills, toddlers' abilities to match their activities to externally defined task standards and to monitor and control activities with respect to outcomes were studied. Children between 15 and 35 months were observed as they engaged in a series of play and clean-up tasks. The results showed that there is a consistent developmental pattern in the extent to which children focus on producing outcomes (rather than on acting for its own sake), the extent to which they monitor, correct, and control activities, and the frequency with which they react to their outcomes with positive affect. These patterns are interpreted in terms of changes in the representation of actions, self-regulation abilities, and the active involvement of the self in actions.

Affect↗
PubMed1993

[Magnetic resonance imaging in chronic toluene abuse, and volitional hyperkinesia].

We described the central nervous system impairments and findings of magnetic resonance imaging (MRI) of the brain in three chronic toluene abusers. Patient 1 and 2 had a history of chronic toluene inhalation for 1 or 2 years and patient 3 has a history of it for 16 years. The patients were evaluated after an abstinence period of at least 4 weeks, to avoid neurologic effects of acute intoxication. Neurologic signs included cerebellar, cognitive and pyramidal dysfunctions in all 3 patients and hyperkinésie volitionnelle (HV; volitional hyperkinesia) in patient 3 who had a long history of toluene inhalation. This HV was found to be tremulous by surface electromyography. Appearance of HV in chronic toluene abuse seems to be related to a period or quantity of inhalation of toluene. T2-weighted MRI in the 3 patients revealed the following abnormalities: (1) increased signal intensity of middle cerebellar peduncle and cerebellar white matter, deep cerebral white matter, and posterior limb of internal capsule; and (2) decreased signal intensity of thalamus and basal ganglia. Proton-weighted MRI in patient 3 with HV showed decreased signal intensity of lateral portion of the thalamus and tegmentum of the brainstem. These MRI findings correlate remarkably well with the neurologic signs seen in the 3 patients. Cerebellar, cognitive, and pyramidal dysfunctions appear to be related to involvement of middle cerebellar peduncle (cerebellar white matter), deep cerebral white matter, and internal capsule, respectively, and HV seems to correlate with involvement of the thalamus or tegmentum of the brainstem, especially the latter.

Adult↗
PubMed2004

Impaired volitional closure of the left eyelid after right anterior cerebral artery infarction: apraxia due to interhemispheric disconnection?

BACKGROUND: The inability of volitional unilateral eyelid closure is an uncommon symptom of a central nervous system disorder. When it occurs as the result of a localized brain lesion, it is debated to be a form of supranuclear facial palsy or an apraxic phenomenon. OBJECTIVES: To report and discuss a unilateral (left-sided) higher-order movement disorder of the facial periocular musculature bearing apraxic features. SETTING: University neurology department. PATIENT: A 78-year-old right-handed man was admitted to the hospital with a left-sided brachiofacial hemiparesis of sudden onset. After thrombolysis with intravenous recombinant tissue-type plasminogen activator, the hemiparesis, including the left-sided facial weakness, disappeared. Serial computed tomographic scans showed that the patient was left with a stroke in the right anterior cerebral artery territory, affecting the frontal commissural fibers of the corpus callosum. There were no signs of upper motor neuron facial paresis on the left side when gesturing in a natural context. Eyelid closure was complete during sleep. However, left eyelid closure and elevation of the left eyebrow were not possible on verbal command. In contrast, voluntary innervation of the perioral facial musculature was performed properly. CONCLUSIONS: The voluntary-automatic dissociation of our patient's eyelid closure was suggestive of an apraxic disorder. Disconnection from a praxis center caused by callosal damage may be assumed to be the underlying cause. The unilaterality of the symptom might imply that in a bilaterally organized corticonuclear system such as upper face innervation, it is the crossing fibers that are primarily involved in praxis tasks.

Aged↗
PubMed2001

Right lateralized motor cortex activation during volitional blinking.

Using H2 15O positron emission tomography in 6 healthy volunteers, we found that self-initiated and externally cued blinking activated the right primary motor cortex and supplementary motor area (SMA). The left dorsolateral prefrontal cortex (DLPFC) and the rostral SMA showed greater activation during the self-initiated task compared to the externally cued task. This study confirms the hypothesis of right hemispheric lateralization of volitional blinking derived from observations in stroke patients. Furthermore, it underscores the role of DLPFC and rostral SMA in self-initiated movements, which has been found in similar experiments with hand movements.

Aged↗
PubMed2006

Hip joint position modulates volitional knee extensor muscle activity after stroke.

Evidence from animal and human models has demonstrated the importance of hip proprioceptors and vestibular inputs in modulating lower-extremity muscle activity through reflex pathways. Comprehension of the role of these sensory inputs following stroke may be important in understanding pathological muscle activity during functional activities. We therefore examined the influence of both hip and head/trunk position on volitional quadriceps activity in chronic stroke and control subjects. With the knee held at 60 degrees, maximal voluntary isometric quadriceps contractions were elicited with trunk orientation (head position) and hip angle systematically positioned at 0 degrees, 45 degrees, and 90 degrees. Integrated electromyographic activity from the quadriceps was compared between groups and conditions. Vasti activity in the stroke group was greater in a seated upright posture (hip flexed) than supine (hip neutral). Controlling for vestibular input, the stroke group demonstrated greater quadriceps activity (VL and RF) with a neutral hip compared to flexion. Such findings may have implications for understanding inappropriate muscle activity during walking after stroke, as hip extension occurs immediately prior to toe off, when inappropriate quadriceps activity is commonly observed.

Adult↗
PubMed1995

Retrieval volition and memorial awareness in stem completion: an empirical analysis.

Facilitation in an incidental test of stem completion shows little influence of depth of processing at study, whereas facilitation in an opposition test (in which subjects give the first word coming to mind, but omit studied words) occurs following graphemic processing, but not following semantic processing. We argue that completions come to mind involuntarily in both tests. Involuntary conscious memory causes studied words to be omitted in an opposition test, but not in an incidental test, so that the difference in priming between tests is a measure of involuntary conscious memory. We obtained data consistent with this hypothesis by making overt the mental activities that occur covertly in an opposition test: (1) an on-line recognition measure in an incidental test showed a strong advantage of semantic over graphemic processing, even though depth of processing exerted little influence on priming; (2) conditionalizing on recognition failure resulted in accurate estimates of opposition performance; and (3) stems were completed much more rapidly in incidental and opposition tests than in an intentional test, in which voluntary retrieval was engaged. The data provide further evidence that retrieval volition (voluntary vs. involuntary) is dissociable from memorial state of awareness (conscious vs. unconscious). We contrast our approach with the process-dissociation approach, which confounds conscious awareness of the past with voluntary retrieval, overlooking involuntary conscious memory.

Adult↗
PubMed1983

The measurement of K+e concentration changes in human muscles during volitional contractions.

Changes of extracellular potassium concentration [( K+]e) were measured in human muscles during volitional isometric contractions using liquid ion-exchanger electrodes. In principle, an intramuscular injection needle containing a microelectrode with a side-pore was inserted into the brachioradialis muscle. After insertion of the needle, the glass ion-selective microelectrode (ISM) could be moved out of the protective trocar shield into the muscle tissue. The average values of [K+]e in human muscles during maximal effort rose from 4.5 mmol/l K+ to 9.5 mmol/l K+. These values correspond closely to those previously found in muscles of experimental animals.

Extracellular Space↗