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PubMed2004

Neural correlates of individual ratings of emotional salience: a trial-related fMRI study.

Accurate appraisal of meaningful environmental signals involves the interpretation of salient information for their intrinsic emotional value and personal relevance. We examined the neural basis for these components of endogenous salience during such appraisals using trial-related functional magnetic resonance imaging (fMRI). Subjects viewed affective pictures and assessed either the emotional intensity or extent of self-relatedness of the content of those pictures. In a parametric factorial design, individualized subjective ratings of these two dimensions were correlated with brain activity. The nucleus accumbens (NAcc) responded to both increasing emotional intensity and self-relatedness. Activity in the amygdala was specifically related to affective judgments and emotional intensity. The volitional act of appraising the extent of personal association specifically engaged the ventral medial prefrontal cortex (MPFC), and additionally recruited dorsal medial frontal regions and insula as the extent of self-relatedness increased. The findings highlight both overlapping and segregated neural representations of intrinsic value and personal relevance during the appraisal of emotional stimuli.

Adolescent↗
PubMed2007

The role of the posterior superior temporal sulcus in the processing of unmarked transitivity.

Is it living or not? The ability to differentiate between animate and inanimate entities is of considerable value in everyday life, since it allows for the dissociation of individuals that may willfully cause an action from objects that cannot. The present fMRI study aimed to shed light on the neural correlates of animacy at a relational-interpretive level, i.e. on the role of animacy in the establishment of relations between entities that are more or less likely to cause an event and differ in their potential to act volitionally. To this end, we investigated the processing of visually presented transitive German sentences (nominative-accusative structures) in which the factors animacy and argument order were manipulated. The relations between the arguments differed in that the animate subject either acted on an inanimate object (a very natural construction in terms of transitivity) or on an animate object (resulting in a sentence deviating from an unmarked transitive structure). Participants performed an acceptability judgment task. Violations of unmarked transitivity yielded a significant activation increase within the posterior left superior temporal sulcus (pSTS), thus suggesting a specific role of this cortical region in the relational use of animacy information. This result indicates that the influence of animacy as a relational feature differs from the impact of this parameter on the word level and is in line with other neuroimaging studies showing an engagement of the pSTS when a matching between syntax and semantics is required. A comparison between object- and subject-initial conditions further revealed a robust effect of argument order in the pars opercularis of the left inferior frontal gyrus (a subregion of Broca's area), thereby replicating previous findings demonstrating a sensitivity of this region to fine-grained language-specific linearization rules.

Adult↗
PubMed2005

Deficits in saccadic eye-movement control in Parkinson's disease.

In contrast to their slowed limb movements, individuals with Parkinson's disease (PD) produce rapid automatic eye movements to sensory stimuli and show an impaired ability to generate voluntary eye movements in cognitive tasks. Eighteen PD patients and 18 matched control volunteers were instructed to look either toward (pro-saccade) or away from (anti-saccade) a peripheral stimulus as soon as it appeared (immediate, gap and overlap conditions) or after a variable delay; or, they made sequential saccades to remembered targets after a variable delay. We found that PD patients made more express saccades (correct saccades in the latency range of 90-140 ms) in the immediate pro-saccade task, more direction errors (automatic pro-saccades) in the immediate anti-saccade task, and were less able to inhibit saccades during the delay period in all delay tasks. PD patients also made more directional and end-point errors in the memory-guided sequential task. Their inability to plan eye movements to remembered target locations suggests that PD patients have a deficit in spatial working memory which, along with their deficit in automatic saccade suppression, is consistent with a disorder of the prefrontal-basal ganglia circuit. Impairment of this pathway may release the automatic saccade system from top-down inhibition and produce deficits in volitional saccade control. Parallel findings across various motor, cognitive and oculomotor tasks suggest a common mechanism underlying a general deficit in automatic response suppression.

Adult↗
PubMed2004

Alternative cognitive therapy for emotional instability (pathologic laughing and crying).

Emotional instability (EI) is involuntary laughing and crying associated with brain damage seen in a variety of disorders. This article discusses occurrence, impact, and diagnosis, and neuroanatomic substrates underlying proposed mechanisms producing EI are outlined and related to traditional drug treatment. An expanded neuroanatomic model is suggested emphasizing the prefrontal cortex as the center integrating information from a complex emotion and sensory loop with motor information destined for the faciorespiratory nuclei in the brainstem. Disturbance at any level in the loop is proposed to produce EI by degrading information to or from the prefrontal cortex, disrupting its inhibitory control of the nuclei. An alternative cognitive therapy for EI was developed to compensate for deficits resulting from structural lesions by strengthening undamaged pathways, which is achieved by superimposing volitional movement on muscles affected during an EI episode. Treatment of 17 patients showed significant reductions in EI severity and occurrence, and in contrast to drug treatments,the effect was sustained at 3- to 6-month follow-up.

Cognitive Behavioral Therapy↗
PubMed2006

The effect of perospirone on auditory P300 in schizophrenia: a preliminary study.

The present study was performed to determine the effect of perospirone, a novel antipsychotic drug with D(2)/5-HT(2A) antagonist and partial 5-HT(1A) agonist properties, on auditory P300 in eight patients with chronic schizophrenia. Switching to an equivalent dose of perospirone from prior antipsychotic medication was associated with a significant improvement in the negative symptoms of the positive and negative syndrome scale (PANSS). The change in P300 amplitude following a switch to perospirone correlated significantly with the improvement of general psychopathology symptoms, as well as with the change in scores on items of delusions, hallucinatory behavior, emotional withdrawal, depression, poor attention, and disturbance of volition. These results suggest that clinical improvement in response to perospirone in some patients may, at least in part, be mediated through cognitive change indexed by P300 in chronic schizophrenia.

Adult↗
PubMed2006

Oxygenation in the motor cortex during exhaustive pinching exercise.

The purpose of this study was to examine the effect of fatigue resulting from exhaustive pinching exercise on frontal and motor cortex activity. Eight healthy subjects (four male and four female) participated in the present study. All subjects performed at 70% of maximal voluntary contraction (MVC) pinching exercise until reaching a state of volitional fatigue. Frontal cortex and motor cortex oxygenation was measured by near-infrared spectroscopy throughout the exhaustive exercise. Frontal cortex and motor cortex oxygenation increased significantly at the 90 and 120 s after the start of exercise compared with the pre-exercise values and these decreased with the time passage. Frontal cortex oxygenation at exhaustion was significantly lower than the 90 and 120 s after the start of exercise, while motor oxygenation at exhaustion was the same value with the pre-exercise value. These findings suggest that the exhaustive exercise induces the decrease of cerebral function and that the fatigue resulting from dynamic exercise decreases the motor cortex activity.

Adult↗
PubMed2006

Cough motor mechanisms.

Cough is a defensive airway mechanisms which involves the sequential activation of several laryngeal and respiratory muscles in the generation of the typical four-phase motor pattern. Activation of such muscles can be considered to represent the "primary" cough motor mechanism, and its functional significance, although complex, appears to be fairly well established. Nonetheless, the outflows of cough are numerous, and may additionally involve the reflex or mechanical activation of other respiratory and non-respiratory motor systems. These additional, or "secondary", outflows of cough can mainly be regarded as being involved in either enhancing the defensive function of cough, or opposing the possible noxious effects exerted by the mechanical stresses of coughing. In addition, both the primary and secondary cough motor mechanisms are known to play multiple functional roles, thus considerably complicating the cough panorama. Finally, some of the secondary cough motor responses, such as the changes in the pattern of breathing, seem to be devoid of any favourable action and their functional meaning, if any, is not fully understood. Although it is well known that all patterns of cough can be produced voluntarily, the extent to which also volitional cough is accompanied by an array of motor responses similar to that of reflex cough remains to be elucidated.

Animals↗
PubMed2005

Dyspnea and leg effort during exercise.

Dyspnea and leg effort are the major symptoms limiting exercise in healthy subjects and in patients with a variety of respiratory disorders. Quantitative measurement of both symptoms may be obtained by category scales such as VAS and Borg, with the latter being widely used. Furthermore, descriptor clusters of dyspnea help to assess some of the reasons for stopping exercise. The intensity of dyspnea and leg effort are similar in different disease states; this symmetry suggests that the limiting discomfort is a function of the intensity of increased motor drive to peripheral and respiratory muscles. An alternative explanation for the factors which limit exercise is that the subjects stop exercise volitionally when the discomfort associated with continuing exercise exceeds that which they are willing to tolerate. Muscle strength contributes to the intensity of dyspnea and leg effort at a given power output: the greater the muscle force, the lower the symptom. Symptoms also correlate with intensity and duration of a task by a power function in such a way that when minimizing the intensity of a given muscular task by prolonging the duration of activity, the symptom is drastically reduced. Skeletal muscle fatigue may be a factor limiting exercise tolerance both in healthy subjects and in patients with cardiorespiratory disorders. In conclusion, symptom measurement complements physiological measurements, both being essential to a comprehensive understanding of exercise tolerance.

Bicycling↗
PubMed2006

Skeletal muscle structure and function in response to electrical stimulation in moderately impaired COPD patients.

STUDY OBJECTIVE: To determine the structural and functional consequences of high-frequency neuromuscular electrical stimulation (hf-NMES) in a group of moderately impaired outpatients with chronic obstructive pulmonary disease (COPD). DESIGN: A prospective, cross-over randomized trial. SETTING: An university-based, tertiary center. PATIENTS AND MATERIALS: Seventeen patients (FEV(1)=49.6+/-13.4% predicted, Medical Research Council dyspnoea grades II-III) underwent 6-weeks hf-NMES (50Hz) and sham stimulation of the quadriceps femoris in a randomized, cross-over design. Knee strength was measured by isokinetic dynamometry (peak torque) and leg muscle mass (LMM) by DEXA; in addition, median cross-sectional area (CSA) of type I and II fibres and capillary-fibre ratio were evaluated in the vastus lateralis. The 6-min walking distance (6MWD) was also determined. RESULTS: At baseline, patients presented with well-preserved functional capacity, muscle strength and mass: there was a significant relationship between strength and type II CSA (P<0.05). NMES was not associated with significant changes in peak torque, LMM or 6MWD as compared to sham (P>0.05). At micro-structural level, however, electrical stimulation increased type II, but decreased type I, CSA; no change, however, was found in the relative fibre distribution or capillary:fibre ratio (P<0.05). There was no significant association between individual changes in structure and function with training (P>0.05). Post-NMES increase in type II CSA was inversely related to baseline mass and strength (P<0.05). CONCLUSION: NMES may promote a modest degree of type II muscle fibre hypertrophy in COPD patients with well-preserved functional status. These micro-structural changes, however, were not translated into increased volitional strength in this sub-population.

Aged↗
PubMed2005

Drug information-seeking intention and behavior after exposure to direct-to-consumer advertisement of prescription drugs.

BACKGROUND: Concerns about direct-to-consumer advertisement's (DTCA's) information quality have raised interest in patients' drug information-seeking after DTCA exposure. OBJECTIVE: To identify predictors of patients' intentions and behaviors to seek drug information from physicians, pharmacists, and the Internet after DTCA exposure, using theories of planned behavior and self-efficacy. METHODS: One thousand patients were randomly selected from 3,000 nationwide osteoarthritic patients. A self-administered survey examined predictors of intention including measurements of attitude toward behavior, subjective norm, perceived difficulty, self-efficacy, controllability, self-identity, intention, exposure to ads, and control variables. After 6 weeks, another survey measured respondents' information-seeking behavior. For patients exposed to DTCA, 6 multiple regressions were performed for information-seeking intention and behavior for 3 information sources: physicians, pharmacists, and the Internet. RESULTS: The response rates were 61.9% and 80.1% for the first survey and the second survey, respectively. Four hundred and fifty-four participants reported exposure to DTCA about arthritis prescription medicines in the previous month. Over 41% of the variance in intention and over 18% of the variance in behavior were explained by the regression procedures. The consistent positive predictors of intention were attitude toward behavior, self-identity, attitude toward DTCAs of arthritis medication, and osteoarthritis pain; while the consistent positive predictors of behavior were intention and osteoarthritis pain. The strongest predictors of intention were self-identity for physicians, subjective norm for pharmacists, and attitude toward behavior for the Internet. Perceived difficulty and self-efficacy did not predict intention, and self-efficacy and controllability did not predict behavior. CONCLUSIONS: DTCA-prompted drug information-seeking may be under patients' complete volitional control. To promote information searching, efforts could be made to affect factors predicting intention. Interventions could address patients' attitude toward behavior, the influence of their important others, and their role as information seeker, respectively, for information sources like the Internet, pharmacists, and physicians.

Adolescent↗
PubMed2004

Safety of zonisamide therapy: prospective follow-up survey.

Zonisamide safety was evaluated based on a postmarketing surveillance study of patients treated for 1-3 years. Nine hundred twenty-eight children and 584 adults (ages 1 month to 79 years), including 372 newly-diagnosed patients, received zonisamide for partial and generalized epilepsies. Of the intractable patients, 1008 received zonisamide in combination with other antiepileptic drugs (AED), and 52 successfully transitioned to zonisamide monotherapy. A total of 1089 adverse events occurred in 476 (31.5%) of 1512 patients. Incidence of adverse effects was significantly lower among patients receiving zonisamide monotherapy than in those receiving polytherapy: 21% (18.9% of children, 29.4% of adults) versus 35.6% (30.4% of children, 41.7% of adults), respectively. The total incidence of adverse effects was lower for children (26.2%) than for adults (39.9%). Most common adverse events included mental/psychiatric symptoms (19.4%), gastrointestinal symptoms (8.7%), and neurological symptoms (5.8%). Effects that seemed unique to zonisamide were impairment of mental function, motivation or volition, and hypohidrosis. Urinary calculi were detected in only two patients (0.13%). Teratogenicity was evaluated in six patients. Two patients on zonisamide monotherapy and three on polytherapy delivered normal children. One of four patients on polytherapy conceived a fetus with a skull defect with cerebral and cerebellar dysgenesis.

Abnormalities, Drug-Induced↗
PubMed2005

Sleep-related erections: clinical perspectives and neural mechanisms.

Involuntary sleep-related erections (SREs) occur naturally during REM sleep in sexually potent men and other mammals. The regularity of their pattern and non-volitional nature made SREs useful clinically for differentiating psychogenic and organic erectile dysfunction (ED) in candidates for surgical intervention. Normative data available for different age groups added to the attractiveness of SRE measurement for clinical decision-making. Clinical SRE testing is less commonly applied today with the advent of minimally invasive medical therapies for ED. Nonetheless, as an objective measure of erectile function, SRE recording for research provides a precise technique for examining the mechanisms of erection and is still conducted to resolve legal disputes. SRE alterations provoked hormonally and pharmacologically are discussed. Different SRE patterns are associated with comorbid factors and some of these are illustrated, described, or both. Recording techniques developed for rats have proved extremely valuable for furthering our understanding of brain centers mediating erectile response. Data from lesion and stimulation studies are examined in the present review, moving us a step closer to understanding the underpinnings of erectile function.

Brain↗
PubMed2005

Trials and tribulations: understanding motivations for clinical research participation amongst adults with cystic fibrosis.

In the context of understanding motivations for clinical research participation, many authors consider issues such as informed consent and how patients perceive the research method and process. However, many investigations focus only on one method of research, most commonly the randomised controlled trial. Understanding how chronically ill members of one specific patient group respond to all requests for research participation are rare. Cystic fibrosis (CF), a genetic condition whereby those affected are used to taking a wide array of treatments and attending a specialist care centre over many years, and are generally knowledgeable about their condition, represents an ideal case for investigating how staff requests for clinical research participation are accepted or declined. Using Bloor's systems of relevance framework for risk behaviour and risk reduction, specialist CF centre patients' motivations for participation or non-participation in clinical research can be understood. The framework takes into account two sets of conceptual oppositions: habituation and calculation, constraint and volition. These oppositions represent a range along a continuum of risk behaviour rather than being absolute distinctions. Decisions to participate are influenced mainly by the patient's state of health at the time of request, the nature of the trial and the social context within which sufferers are placed. Understanding why chronically ill patients refuse some requests and yet accept others may assist researchers in designing protocols that take these factors into account and achieve the desired numbers of participants whilst protecting those in vulnerable positions.

Adolescent↗
PubMed2006

The poverty-HIV/AIDS nexus in Africa: a livelihood approach.

This paper reviews the nexus between poverty and HIV/AIDS in Africa using a sustainable livelihood framework. Much of the literature on HIV and AIDS has generated an almost universal consensus that the AIDS epidemic is having an immense impact on the economies of hard-hit countries, hurting not only individuals, families and firms, but also significantly slowing economic growth and worsening poverty. International evidence has concentrated on the pathways through which HIV/AIDS undermines livelihoods and raises vulnerability to future collapse of livelihoods. Yet, little attention has been paid to the role that social relations and livelihood strategies can play in bringing about risky social interaction that raises the chance of contracting HIV. Using the sustainable livelihood and social relation approaches, this article demonstrates that although AIDS is not simply a disease of the poor, determinants of the epidemic go far beyond individual volition and that some dimensions of being poor increase risk and vulnerability to HIV.

Africa↗
PubMed2006

Stimulus factors affecting illusory rebound motion.

Stimulus attributes that influence a recently reported illusion called "illusory rebound motion" (IRM; [Hsieh, P.-J., Caplovitz, G. P., & Tse, P. U. (2005). Illusory rebound motion and the motion continuity heuristic. Vision Research, 45, 2972-2985.]) are described. When a bar alternates between two different colors, IRM can be observed to traverse the bar as if the color were shooting back and forth like the opening and closing of a zipper, even though each color appears in fact all at once. Here, we tested IRM over dynamic squares or disks defined by random dot or checkerboard textures to show that (1) IRM can be perceived in the absence of first-order motion-energy (or when the direction of net first-order motion-energy is ambiguous); (2) the direction of IRM is multistable and can change spontaneously or be changed volitionally; and (3) the perceived frequency of IRM is affected by several factors such as the contours of the stimulus, stimulus texture, and motion-energy.

Artifacts↗
PubMed2004

Practical markers of the transition from aerobic to anaerobic metabolism during exercise: rationale and a case for affect-based exercise prescription.

BACKGROUND: The high rates of dropout from exercise programs may be attributed in part to the poor ability of most individuals to accurately self-monitor and self-regulate their exercise intensity. The point of transition from aerobic to anaerobic metabolism may be an appropriate level of exercise training intensity as it appears to be effective and safe for a variety of populations. Possible practical markers of this event were compared. METHODS: Two samples of 30 young and healthy volunteers each participated in incremental treadmill tests until volitional exhaustion. The ventilatory threshold, a noninvasive estimate of the aerobic-anaerobic transition, was identified from gas exchange data. Heart rate, self-ratings of affective valence (pleasure-displeasure), perceived activation, and perceived exertion were recorded every minute. RESULTS: In both samples, heart rate, perceived activation, and perceived exertion rose continuously, whereas the ratings of affective valence showed a pattern of quadratic decline, initiated once the ventilatory threshold was exceeded. CONCLUSIONS: Exercise intensity that exceeds the point of transition from aerobic to anaerobic metabolism is accompanied by a quadratic decline in affective valence. This marker may be useful in aiding exercisers to recognize the transition to anaerobic metabolism and, thus, more effectively self-monitor and self-regulate the intensity of their efforts.

Adult↗
PubMedDate not supplied

Evaluating the effects of interface factors on the torque exertion capabilities of operating handwheels.

This study intends to assess factors affecting human torque exertion capabilities of operating valve handwheels (maximum volitional torque exertion of wrist radial/ulnar deviation, R/U MVTE). Forty student subjects (20 males and 20 females) participated in this study. In addition to gender and subject factors, gloves (one layer of cotton, two layers of cotton and rubber gloves), operating height (elbow, shoulder and overhead), handwheel size and shape were selected. Barehanded condition was also involved. The results indicate that all the main effects and the first order interactions were significant. The gloved R/U MVTEs were found to be greater than the barehanded R/U MVTE. For operating height, shoulder height gave the greatest R/U MVTE, followed by elbow and overhead heights. The handwheel diameters ranging from 75 to 95 mm for males and 65 to 80 mm for females were found to have the greater R/U shear force. The average R/U MVTE of operating valve handwheel for females was about 63% (3.8/6.05) of that of males.

Accidents, Occupational↗
PubMed2003

Agonist contractions against electrically stimulated antagonists.

OBJECTIVE: To assess an exercise program that uses electrically stimulated antagonists to resist agonist muscle contractions. DESIGN: In 1 limb, electrically stimulated antagonists resisted elbow flexion and extension. In the other, stimulation occurred without volitional muscle contraction. SETTING: A biomechanics laboratory in Japan. PARTICIPANTS: Twelve men between the ages of 19 and 24 years. Subjects served as their own controls. INTERVENTION: Subjects trained 3 times a week for 12 weeks. Each session consisted of 10 sets of 10 elbow flexor and extensor contractions. MAIN OUTCOME MEASURES: Isokinetic elbow extension and flexion torques. Biceps and triceps brachii cross-sectional areas. RESULTS: Elbow extension torques increased (32.85% at 30 degrees/s, 27.20% at 60 degrees/s, 26.16% at 90 degrees/s; all P<or=.02) over the training period in limbs that trained against electrically stimulated antagonists. Control limb extension torque increases were smaller (8.52% -14.91%) and did not reach statistical significance. Elbow flexion torques improved in both groups, but the changes did not reach statistical significance. Cross-sectional areas increased in all muscles but were most marked in the antagonist stimulated limbs: triceps 16.20% versus 4.25% (P=.01) and biceps 16.65% versus 7.00% (P=.005). CONCLUSIONS: Exercises that use electrically stimulated antagonist muscles may be effective in increasing muscle strength and mass.

Adult↗