Biomedical subjects

Asako Yasuda

Publications and source records attributed to Asako Yasuda.

7 recordsLinked to original sources

PubMed2006

Changes in cerebral glucose utilization in patients with panic disorder treated with cognitive-behavioral therapy.

Several neuroanatomical hypotheses of panic disorder have been proposed focusing on the significant role of the amygdala and PAG-related "panic neurocircuitry." Although cognitive-behavioral therapy is effective in patients with panic disorder, its therapeutic mechanism of action in the brain remains unclear. The present study was performed to investigate regional brain glucose metabolic changes associated with successful completion of cognitive-behavioral therapy in panic disorder patients. The regional glucose utilization in patients with panic disorder was compared before and after cognitive-behavioral therapy using positron emission tomography with (18)F-fluorodeoxyglucose. In 11 of 12 patients who showed improvement after cognitive-behavioral therapy, decreased glucose utilization was detected in the right hippocampus, left anterior cingulate, left cerebellum, and pons, whereas increased glucose utilization was seen in the bilateral medial prefrontal cortices. Significant correlations were found between the percent change relative to the pretreatment value of glucose utilization in the left medial prefrontal cortex and those of anxiety and agoraphobia-related subscale of the Panic Disorder Severity Scale, and between that of the midbrain and that of the number of panic attacks during the 4 weeks before each scan in all 12 patients. The completion of successful cognitive-behavioral therapy involved not only reduction of the baseline hyperactivity in several brain areas but also adaptive metabolic changes of the bilateral medial prefrontal cortices in panic disorder patients.

Adult↗

PubMed2005

Cerebral glucose metabolism associated with a fear network in panic disorder.

The present study was performed to assess cerebral glucose metabolism in patients with panic disorder using positron emission tomography. F-fluorodeoxyglucose positron emission tomography with voxel-based analysis was used to compare regional brain glucose utilization in 12 nonmedicated panic disorder patients, without their experiencing panic attacks during positron emission tomography acquisition, with that in 22 healthy controls. Panic disorder patients showed appreciably high state anxiety before scanning, and exhibited significantly higher levels of glucose uptake in the bilateral amygdala, hippocampus, and thalamus, and in the midbrain, caudal pons, medulla, and cerebellum than controls. These results provided the first functional neuroimaging support in human patients for the neuroanatomical hypothesis of panic disorder focusing on the amygdala-based fear network.

Adult↗

PubMed2005

Explicit knowledge and intention to learn in sequence learning: an event-related potential study.

The present study was performed to examine how intention to learn and explicit knowledge in sequence learning are reflected in event-related potentials. Participants responded to numerals presented in a repeating order, which were replaced infrequently by deviant numerals. The participants were given incidental or intentional learning instructions. Sequence parts for which they acquired explicit knowledge were identified for each participant by post-task memory tests. Reaction times indicated that sequence learning occurred under both types of instruction. The N2 enhancement for deviants was primarily associated with explicit sequence knowledge, and the P3 enhancement showed a weak association. These results suggested that N2 and P3 reflect different aspects of explicit learning.

Adolescent↗

PubMed2005

Effects of value and reward magnitude on feedback negativity and P300.

Feedback negativity is a negative component of the event-related brain potential observed 250-300 ms after feedback stimuli. The present study investigated the effects of value (correct or incorrect) and reward magnitude (no, small or large) on feedback negativity and P300. Feedback negativity was larger after incorrect feedback than after correct feedback, irrespective of reward magnitude. In contrast, P300 amplitude increased with reward magnitude, irrespective of value. The amplitude of feedback negativity was correlated with a trait score of negative affect and not positive affect, whereas P300 amplitude was correlated with positive affect and not negative affect. These results suggest that value and reward magnitude are processed separately in the brain.

Adult↗

PubMed2005

Illusion of sense of self-agency: discrepancy between the predicted and actual sensory consequences of actions modulates the sense of self-agency, but not the sense of self-ownership.

It is proposed that knowledge of motor commands is used to distinguish self-generated sensation from externally generated sensation. In this paper, we show that the sense of self-agency, that is the sense that I am the one who is generating an action, largely depends on the degree of discrepancy resulting from comparison between the predicted and actual sensory feedback. In Experiment 1, the sense of self-agency was reduced when the presentation of the tone was unpredictable in terms of timing and its frequency, although in fact the tone was self-produced. In Experiment 2, the opposite case was found to occur. That is, participants experienced illusionary sense of self-agency when the externally generated sensations happened to match the prediction made by forward model. In Experiment 3, the sense of self-agency was reduced when there was a discrepancy between the predicted and actual sensory consequences, regardless of presence or absence of a discrepancy between the intended and actual consequences of actions. In all the experiments, a discrepancy between the predicted and actual feedback had no effects on sense of self-ownership, that is the sense that I am the one who is undergoing an experience. These results may suggest that both senses of self are mutually independent.

Adult↗

PubMed2004

Error-related negativity reflects detection of negative reward prediction error.

Error-related negativity (ERN) is a negative deflection in the event-related potential elicited in error trials. To examine the function of ERN, we performed an experiment in which two within-participants factors were manipulated: outcome uncertainty and content of feedback. The ERN was largest when participants expected correct feedback but received error feedback. There were significant positive correlations between the ERN amplitude and the rate of response switching in the subsequent trial, and between the ERN amplitude and the trait version score on negative affect scale. These results suggest that ERN reflects detection of a negative reward prediction error and promotes subsequent response switching, and that individuals with high negative affect are hypersensitive to a negative reward prediction error.

Adult↗

PubMed2002

[Development of the behavioral inhibition system/behavioral approach system scales].

The purpose of present studies was to create brief self-report scales to assess individual differences in the sensitivity of two neurological self-regulatory systems; one is the behavioral inhibition system (BIS) which bears on aversive motivation, and the other is the behavioral approach system (BAS) which bears on appetitive motivation. Scale development was reported in study 1, and convergent and discriminant validation using alternative measures of similar constructs was reported in study 2. In study 3, positive and negative affect was manipulated in a controlled setting. Results were consistent with the hypothesis that participants with higher BIS sensitivity would show heightened emotional reactivity to negative mood induction, whereas higher BAS sensitivity would show heightened reactivity to positive mood induction. Furthermore, results indicated that higher BAS sensitivity not only inhibited negative affect in response to negative mood induction but also facilitated recovery from negative mood states. These results suggested that abnormal sensitivity of either system may be a vulnerability factor of psychopathology, when specific situational cues are present.

Adult↗