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161.
Riecker A Ackermann H Wildgruber D Meyer J Dogil G Haider H Grodd W 《Brain and language》2000,75(2):259-276
Damage to the anterior peri-intrasylvian cortex of the dominant hemisphere may give rise to a fairly consistent syndrome of articulatory deficits in the absence of relevant paresis of orofacial or laryngeal muscles (apraxia of speech, aphemia, or phonetic disintegration). The available clinical data are ambiguous with respect to the relevant lesion site, indicating either dysfunction of the premotor aspect of the lower precentral gyrus or the anterior insula in the depth of the Sylvian fissure. In order to further specify the functional anatomic substratum of this syndrome, functional magnetic resonance imaging (fMRI) was performed during reiteration of syllables differing in their demands on articulatory/phonetic sequencing (CV versus CCCV versus CVCVCV). Horizontal tongue movements and a polysyllabic lexical item served as control conditions. Repetition of the CV and CCCV monosyllables elicited a rather bilateral symmetric hemodynamic response at the level of the anterior and posterior bank of the central sulcus (primary sensorimotor cortex), whereas a more limited area of neural activity arose within this domain during production of lexical and nonlexical polysyllables, significantly or exclusively lateralized toward the left hemisphere. There is neurophysiological evidence that primary sensorimotor cortex mediates the "fractionation" of movements. Assuming that the polysyllables considered are organized as coarticulated higher-order units, the observed restricted and lateralized cortical activation pattern, most presumably, reflects a mode of "nonindividualized" motor control posing fewer demands on "movement fractionation." These findings may explain the clinical observation of disproportionately worse repetition of trisyllabic items as compared to monosyllables in apraxia of speech. The various test materials failed to elicit significant activation of the anterior insula. If at all, only horizontal tongue movements yielded a hemodynamic reaction extending beyond the sensorimotor cortex to premotor areas. Since limbic projections target the inferior dorsolateral frontal lobe, the enlarged region of activation during horizontal tongue movements might reflect increased attentional requirements of this task. 相似文献
162.
ERPs and behavioral inhibition in a Go/No-go task in children with attention-deficit hyperactivity disorder 总被引:3,自引:0,他引:3
Yong-Liang G Robaey P Karayanidis F Bourassa M Pelletier G Geoffroy G 《Brain and cognition》2000,43(1-3):215-220
In order to study the behavioral responses and the brain inhibition process in children with attention-deficit hyperactivity disorder (ADHD), Event-Related Potentials (ERPs) were recorded from 30 scalp electrodes in 21 ADHD and 21 normal boys during performing a Go/No-go task. ADHD children made fewer correct responses to both Go and No-go stimuli than normal controls. The frontal N2 amplitude was larger for No-go stimuli than Go stimuli in both groups, reflecting inhibition of responding. Smaller N2 amplitudes to No-go stimuli were found in ADHD children, but only when the Go/No-go task was performed after a first stimulus-response compatibility (SRC) task. In addition, the controls exhibited a prolonged N2 only when the Go/No-go task was performed second. However, the ADHD subjects exhibited this prolonged N2 when the task was first, but not when it was second. These results suggest an inhibitory regulation problem rather an inhibition deficit in ADHD children. 相似文献
163.
The measurement of “switch costs” is held to be of interest because, as is widely believed, they may reflect the control
processes that are engaged when subjects switch between two (or more) competing tasks. [In task-switching experiments, the
reaction time (RT) switch cost is typically measured as the difference in RT between switch and non-switch (repeat) trials.]
In this report we focus on the RT switch costs that remain even after the subject has had some time to prepare for the shift
of task, when the switch cost may be approximately asymptotic (so-called residual switch costs). Three experiments are presented.
All three experiments used Stroop colour/word, and neutral stimuli. Participants performed the two tasks of word-reading and
colour-naming in a regular, double alternation, using the “alternating runs” paradigm (R. D. Rogers & S. Monsell, 1995). The
experiments were designed to test the hypothesis that RT switch costs depend on a form of proactive interference (PI) arising
from the performance of a prior, competing task. A. Allport, E. A. Styles and S. Hsieh (1994) suggested that these PI effects
resulted from “task-set inertia”, that is, the persisting activation-suppression of competing task-sets, or competing task-processing
pathways. The results confirmed the existence of long-lasting PI from the competing task as a major contributor to switch
costs. Non-switch trials, used as the baseline in the measurement of switch costs, were also shown to be strongly affected
by similar PI effects. However, task-set inertia was not sufficient to account for these results. The results appeared inconsistent
also with all other previous models of task switching. A new hypothesis to explain these between-task interference effects
was developed, based on the stimulus-triggered retrieval of competing stimulus-response (S-R) associations, acquired (or strengthened)
in earlier trials. Consistent with this retrieval hypothesis, switch costs were shown to depend primarily on the S-R characteristics
of the preceding task (the task that was switched from) rather than the upcoming task. Further, the effects of the other,
competing task were found to persist over many successive switching trials, affecting switch costs long after the stimulus
overlap (and hence the principal S-R competition) between the current tasks had been removed. Switch costs were also found
to be affected by recent, item-specific experience with a given stimulus, in either the same or the competing task. Finally,
the results showed that switch costs were massively affected by the ratio of the number of prior trials, in response to the
same stimuli, that had implemented either the currently intended or the competing S-R mappings. None of these effects are
predicted by current models of residual switch costs, which appeal to the differences in control processes assumed to be engaged
in switch versus non-switch trials.
Received: 31 March 1999 / Accepted: 23 July 1999 相似文献
164.
We propose an extension of a systemic model for object recognition formulated by Rybak et al (1998 Vision Research 38 2387-2400) which is based on the functional organisation of the visual systems in primate brains. In contrast to the learning and recognition scheme of Rybak et al we do not assume a behavioural paradigm, i.e. a visuomotor programmed scanpath that determines the sequence of foveation on the different parts of the object. As in the basis architecture of Rybak et al, the system modules are separated into 'what'-like subsystems corresponding to the ventral occipito-inferotemporal visual path and 'where'-like complexes analogous to the dorsal occipito-parietal visual path. The 'what' system analyses local features in the actual foveation as in Rybak et al. But, in our case, the 'where' memory, instead of programming a behavioural scanpath, scores the spatial relationship between successive fixation and the spatial relationship between the associated main edges. The recognition is based on the identification of parts and their spatial relationship. This gives the learning and recognition mechanisms more flexibility in the sense that, for recognising an object, several different fixation sequences may be accepted. 相似文献
165.
Our objective was to examine whether the SCL-90-R, a widely used self-report measure of distress and psychopathology, could screen for personality disorders in general and for severe personality disturbance (SPD) in particular, at the time when patients seek treatment for a state (mood or anxiety) disorder. The SCL-90-R was administered to 112 consecutive outpatients with various mood and anxiety disorders. The personality severity index (PSI) score, defined as the mean value of the scores on the SCL-90-R subscales of interpersonal sensitivity, hostility, and paranoid ideation, was compared with the current symptom index (CSI) score, defined as the mean value of the scores on the remaining six SCL-90-R subscales. A positive screen was considered if PSI > CSI. SPD was defined as the presence of any DSM-III-R Cluster A and/or Cluster B personality disorder. The accuracy of the screen was verified by means of the Structured Clinical Interview for DSM-III-R Personality Disorders. The sensitivity of the PSI > CSI criterion to screen for SPD was 89.4%, while its sensitivity to screen for any DSM-III-R personality disorder was 72.9%. The SCL-90-R subscales that contributed the most to the screening discriminability of this SCL-90-R-derived screening measure were hostility, paranoid ideation, somatization, and obsessive-compulsive behavior. The SCL-90-R may be used to screen for SPD in routine work with outpatients with mood and anxiety disorders, but the results of the screening need to be verified because of the possibility of false negatives and false positives, although that possibility is apparently low. These findings may have important prognostic and treatment implications. 相似文献
166.
Pollok B Prior H Güntürkün O 《Journal of comparative psychology (Washington, D.C. : 1983)》2000,114(2):148-157
The development of object permanence was investigated in black-billed magpies (Pica pica), a food-storing passerine bird. The authors tested the hypothesis that food-storing development should be correlated with object-permanence development and that specific stages of object permanence should be achieved before magpies become independent. As predicted, Piagetian Stages 4 and 5 were reached before independence was achieved, and the ability to represent a fully hidden object (Piagetian Stage 4) emerged by the age when magpies begin to retrieve food. Contrary to psittacine birds and humans, but as in dogs and cats, no "A-not-B error" occurred. Although magpies also mastered 5 of 6 invisible displacement tasks, evidence of Piagetian Stage 6 competence was ambiguous. 相似文献
167.
LINDZEY G 《Psychological bulletin》1959,56(2):158-168
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