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Results for “Task Shifting”

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PubMed2005

Rightward shift in spatial awareness with declining alertness.

Although transient neglect of contralesional space occurs following damage to either hemisphere, persistent forms are overwhelmingly associated with right hemisphere lesions. This has led to the suggestion that impairments in other right hemisphere systems--in particular those that mediate alertness--may undermine recovery. Reductions in neglect severity with stimulation, exacerbation with sedatives and the poor performance of chronic neglect patients on sustained attention tasks are consistent with this view. However, the question of whether changes in alertness exert a specific influence over spatial attention--or simply improve performance across many domains--is difficult to address using only patient studies. Here, we examine this question with individuals from the healthy adult population. On certain spatial tasks, adults show a modest but reliable leftward attentional bias. On the basis of the neglect studies, we hypothesised that this bias would diminish--or even reverse--as alertness levels declined. In the first study, participants were asked to judge the relative lengths of the left and right sections of a line when sleep deprived and when well rested. A significant rightward shift in attention was associated with sleep deprivation. A rightward shift was also observed over the course of the session. The second study replicated this time-on-task effect. The results suggest that a diminution in alertness may be sufficient to induce a rightward shift in visual attention in the healthy brain. Implications for the persistence of neglect in patients, for spatial biases in children and for normal free viewing asymmetries are discussed.

Adult↗

PubMed1995

Preferential looking: a sudden shift in visual fixation pattern at 32 months of age.

Observations of eye movements of young children in a modified preferential looking task suggest a change in the visual looking pattern taking place during a very brief time between 32 and 33 months of age. In the younger children, a grating stimulus elicited eye movements towards the target followed by a few seconds of focused attention; in the older children a visual avoidance behavior was observed where subjects looked consistently in the opposite direction of the target. An analysis of video recordings suggests that this avoidance pattern was a composite of a very brief initial target-directed eye movement which was quickly arrested, and followed by eye movements in the opposite direction, initiating a search of the visual scene.

Attention↗

PubMed1989

Children's solution strategies and mental rotation: evidence for a developmental shift.

We examined children's ability to anticipate the appearance of transformed multicomponents using visual stimuli with variations of a mental rotation task. We hypothesized that (a) performance would depend on the presence, location, and spatial relationship of specific stimulus features, and that (b) younger children would use a single component to make their predictions, whereas older children would be more likely to use multiple components. In Study 1, 40 first-, and fifth-grade subjects were presented with 32 rotation problems consisting of varied stimulus characteristics; subjects selected the correct option from a field where foils were indicative of the strategy used. Analyses of variance and log linear analyses revealed the hypothesized stimulus effect differentially associated with the children's ages. In Study 2, sixty 5-, 7-, and 9-year olds confronted 64 mental rotation problems with multicomponent stimuli and a construction task. Results and implications confirmed those of Study 1.

Attention↗

PubMed1987

Effects of attention and slow potential shifts on self-regulation of event-related potentials.

Research on the effects of self-regulation of slow potentials (SP) and event-related potentials (ERP) has failed to look at the possible interactions of these two kinds of brain potentials. The present study investigated such interactions by recording both ERP and SP potential changes in an operant ERP conditioning paradigm. Ten subjects participated in two conditions that were designed to differentially manipulate attention to the stimuli. In the operant conditioning task, subjects received auditory feedback as they attempted to increase the ERP amplitude at 180 msec poststimulus (P180), which was elicited by a subpainful shock stimulus to the forearm over 250 trials. In the distraction task, subjects were instructed not to attend to stimuli or feedback tones, but rather received and were tested on reading materials. Attention, as manipulated by these tasks, was not a determinant of changes in ERP amplitude since there were no significant differences in the size of P180 between attention conditions. While no significant change in the mean ERP amplitude occurred, subjects were able to produce ERPs above criterion threshold significantly more often during trials in the conditioning task than in the reading task. Thus, there was evidence of some learning. The difference in wave forms between hit and miss trials indicates a latency shift (with misses having a later ERP peak). This may indicate that latency, rather than, or in addition to, amplitude, is shaped during conditioning procedures. In addition, the CNV that developed between the shock stimulus and the feedback signal during conditioning was significantly larger in amplitude than in the distraction condition. This is taken as evidence of increased attention during conditioning. Since hit trials demonstrated larger contingent negative variation (CNV) amplitudes, production of CNVs may be instrumental in mediating hits. Therefore, attentional mechanisms may play a role in successful ERP self-regulation. No correlations were found involving P180, CNVs, or tonic slow potential shifts. Changes in tonic DC levels showed a suggestive trend between conditions. Although both conditions began with a negative shift, during conditioning the negativity increased, while during distraction the tonic level went to positivity. These trends support the hypothesis that attention and arousal increased during conditioning. The possible reasons for the lack of significant correlations between ERP and tonic or phasic slow potential changes in this paradigm are discussed.

Adolescent↗

PubMed1996

The shifting gender composition of psychology. Trends and implications for the discipline.

Psychology, along with the majority of professions and scientific disciplines, has undergone dramatic shifts in gender composition over the past two decades. These changes have prompted concern that this increased participation by women may lead to erosion in the status of these occupations. This article describes the results of a case study of psychology conducted by a subcommittee of the American Psychological Association's (APA's) Task Force on the Changing Gender Composition of Psychology to examine the discipline's changing gender composition and the factors related to these shifts. Societal and disciplinary trends are examined, along with data on the patterns of men's and women's involvement in the educational pipeline and workplace. The results provide little support for the concern over the increasing representation of women and its impact on the prestige of the discipline. Rather, they suggest that changes in the nature and status of psychology per se may be at least partly responsible for the changes in male and female participation and that the nature, magnitude, and causes of these disciplinary changes require further examination. Specific recommendations for the APA prepared by another subcommittee of the Task Force are also presented in the Appendix.

Employment↗

PubMed1990

The effects of task duration on psychophysically-determined maximum acceptable weights and forces.

The purpose of this experiment was to investigate maximum acceptable weights and forces when performing manual handling tasks continuously for four hours at frequencies of 4.3 min-1 or slower. Twelve female and ten male second shift industrial workers performed 18 varieties of lifting, lowering, pushing, pulling, and carrying. A psychophysical methodology was employed, whereby the subjects were asked to select a workload they could sustain for 8 h 'without straining themselves or without becoming unusually tired, weakened, overheated or out of breath'. Measurements of heart rate, oxygen consumption, dynamic and static strengths were also taken. The weights selected after 40 min were not significantly different from the weights selected after four hours. The average oxygen consumption for the fast tasks was 28% VO2 max, within physiological guidelines for eight hours. The results also revealed that the maximum acceptable weights for the combination task of lifting, carrying, and lowering were limited by the lifting and lowering components. It is concluded from the results of this study that the psychophysical methodology is appropriate for determining maximum acceptable weights for task frequencies of 4.3 min-1 or slower. It is also concluded that the maximum acceptable weight for a combination task is limited by the lowest acceptable weight of any of the components.

Adult↗

PubMed2000

Implication of sensorimotor integration in the generation of periodic dystonic myoclonus in subacute sclerosing panencephalitis (SSPE).

To clarify the mechanism of periodic dystonic myoclonus in subacute sclerosing panencephalitis (SSPE), a 22-year-old patient with a clinical diagnosis of SSPE was electrophysiologically investigated. Involuntary movements consisted of generalized dystonic posturing which occurred quasiperiodically once every 4 to 8 seconds. Effects of sensory stimuli and voluntary movements were studied by means of polygraphic recording of surface electromyogram (EMG), scalp electroencephalogram (EEG), and magnetoencephalogram (MEG). EEG showed quasi-periodic, generalized, transient complexes synchronous to each dystonic myoclonus, which were preceded by a slow negative EEG shift at the parietal region by approximately 5 seconds. Neither external stimuli nor self-paced movements alone influenced the periodicity of dystonic myoclonus or EEG complexes. In the reaction time task, however, the external stimuli given as an imperative cue to execute a motor task elicited dystonic myoclonus and generalized EEG complexes only if they were presented in the latter segment of the interval between the two successive EEG complexes while the slow negative EEG shift appeared. These findings suggest that EEG complexes and periodic movements spontaneously occur when cortical excitability reaches a certain critical level, but both phenomena are elicited even before if the sensory stimuli as an imperative signal requiring motor execution are presented. This finding most likely implies involvement of the sensorimotor integration mechanism in these periodic phenomena.

Adult↗

PubMed1982

Spontaneous cortical slow-potential shifts and choice reaction time performance.

EEGs from Fz, Cz and Pz locations (reference--right mastoid) were obtained from 36 adults. For experimental trials the Fz slow potentials (SP) were determined for a pretask interval of: a 3 sec baseline, followed by a 2.5 sec SP shift, in either negative (3.5 microV) or positive (1.5 microV) direction, and maintenance at this level for another 2.5 sec. When this criterion was met the stimuli for a choice RT task were presented (potential-related event, PRE), which required a button-press response with the right or left hand for differing stimulus configurations. During subsequent control sessions subjects were tested without pretask criterion SP shifts, with yoked pretask intervals from the experimental sessions. For the experimental conditions the mean RTs were significantly faster and less variable with the negative than with the positive SP shift condition. For the control conditions mean RTs were somewhat faster for the positive than for the negative criterion, which might be attributed to the more variable pretask intervals during the latter polarity condition. For confirmation of the cortical localization of this effect, the experimental session was replicated with corresponding negative and positive SP shift criteria from Pz. No significant differences among means and standard deviations of RTs were found. SP shifts from criterion electrodes (Fz or Pz) were significantly greater in mean amplitude than the concomitant SP shifts from the other electrodes. The present findings demonstrate the feasibility of the PRE methodology for investigations of human brain functions.

Adult↗

PubMed2004

Intention-based and stimulus-based mechanisms in action selection.

Human actions can be classified as being either more stimulus-based or more intention-based. According to the ideomotor framework of action control, intention-based actions primarily refer to anticipated action effects (in other words response-stimulus [R-S] bindings), whereas stimulus-based actions are commonly assumed to be more strongly determined by stimulus-response [S-R] bindings. We explored differences in the functional signatures of both modes of action control in a temporal bisection task. Participants either performed a choice response by pressing one out of two keys in response to a preceding stimulus (stimulus-based action), or pressed one out of two keys to produce the next stimulus (intention-based action). In line with the ideomotor framework, we found intention-based actions to be shifted in time towards their anticipated effects (the next stimulus), whereas stimulus-based actions were shifted towards their preceding stimulus. Event-related potentials (ERPs) in the EEG revealed marked differences in action preparation for the two tasks. The data as a whole provide converging evidence for functional differences in the selection of motor actions as a function of their triggering conditions, and support the notion of two different modes of action selection, one being exogenous or mainly stimulus-driven, the other being endogenous or mainly intention-driven.

Adult↗

PubMed2003

Measuring impulsivity in mice using a novel operant delayed reinforcement task: effects of behavioural manipulations and d-amphetamine.

RATIONALE: The increasing use of genetically modified mice to probe genetic contributions to normal and abnormal behaviours requires the development of sensitive and selective behavioural tasks. OBJECTIVES: To develop a discrete trial assay of impulsivity (delayed reinforcement) that is tractable in mice utilising a mouse operant nine-hole box apparatus and to specify the task with respect to behavioural and pharmacological manipulations. METHODS: Mice were trained to respond with a nose-poke to one of two visual stimuli; one response resulted in a small quantity of reinforcer, the other in a larger quantity of reinforcer. As the session proceeded increasing delay was introduced onto the response leading to the large reward. Hence, the nature of the choice was a small quantity of reinforcer immediately versus a larger but progressively delayed amount of reinforcer. At stable baseline performance the mice were challenged with a variety of task manipulations and systemic d-amphetamine in order to discern aspects of the underlying psychological and neurochemical substrates of the choice behaviour. RESULTS: The mice showed a systematic shift in responding away from the large reinforcer with increasing delay (0, 2, 4, 8, 12 s), such that at the longest delay >80% of nose-pokes were for the smaller, immediate reinforcer. Task manipulations indicated that behaviour was controlled in a trial discrete manner by the contingency between delay and reward and was not due to non-specific factors such as satiation. d-Amphetamine had complex, dose dependent effects on choice behaviour which revealed dissociations between impulsive choice and hyperactivity. CONCLUSIONS: We have successfully developed an assay of impulsivity in mice that will be of utility to examine impulsive behaviours and their genetic substrates. In addition, our data provided evidence of distinct dopaminergic mechanisms mediating aspects of impulsivity and hyperactivity.

Amphetamine↗

PubMed2001

Evidence for an analytic perception of multiharmonic sounds in the bat, Megaderma lyra, and its possible role for echo spectral analysis.

For echolocation, the gleaning bat Megaderma lyra relies on short and broadband calls consisting of multiple harmonic components, each of which is downward frequency modulated. The harmonic components in M. lyra's calls have a relatively small frequency excursion and do not overlap spectrally. Broadband calls of other bat species, on the other hand, often consist of only a few harmonics which are modulated over broad and sometimes overlapping frequency ranges. A call consisting of narrow and nonoverlapping harmonic components may provide a less complete representation of target structure than a call which consists of broadly modulated components. However, a multiharmonic call may help the bats to perceive local spectral changes in the echo from shifts in the peak frequencies of single harmonics, and thereby to extract additional information about the target. To assess this hypothesis, the accuracy with which M. lyra can analyze frequency shifts of single partials in multiharmonic complex tones was investigated. A two-alternative, forced-choice behavioral task was used to measure M. lyra's frequency discrimination threshold for the third partial in complex tones whose spectral composition resembled that of the bat's sonar calls. The discrimination threshold for the third partial in a 21.5-kHz harmonic tone amounted to about 2% and was similar to the bat's pure-tone discrimination threshold at 64.5 kHz. Discrimination performance was essentially unaffected by random frequency changes of the other partials and by reducing stimulus duration from 50.5 to 1.5 ms. Both findings are in accordance with predictions made on the basis of the shape of M. Ivra's cochlear filters. The comparison between the observed frequency discrimination performance and a computational estimate of the expected frequency shift in the third harmonic of an echo reflected by a simple, two-front target showed that M. lyra's frequency resolution is sufficient for analyzing the target-specific information conveyed by shifts in the peak frequency of single echo components.

Animals↗

PubMed1997

The primate striatum: neuronal activity in relation to spatial attention versus motor preparation.

The primate basal ganglia are known to be involved in the initiation and control of visually guided movements. However, the precise role of these structures is not clear, partly because most neurophysiological studies have not dissociated neuronal activity related to visuomotor processing from that reflecting other aspects of behaviour, such as shifts of spatial attention. Moreover, the way the basal ganglia function together with the frontal cortex during movement initiation and execution is still a matter of debate. In an effort to clarify these issues, we recorded single neurons from the striatum (caudate nucleus and putamen) in two rhesus monkeys trained to perform a conditional visuomotor task, and compared their properties with those of the frontal cortex. The experimental paradigm was designed to distinguish neuronal activity associated with shifts of attention from that reflecting motor preparation. In a given trial, an identical visual stimulus could serve as a cue for the reorientation of spatial attention or as a cue for establishing a motor set depending on when it occurred during that trial. Additional aspects of the paradigm were designed to identify neurons whose activity differed when various stimulus configurations instructed the same action (stimulus effect), as well as neurons whose activity differed when two different actions were instructed by the same stimulus (movement effect). The majority of cells (60%) were preferentially active after instructional cues, 38% discharged preferentially after attentional cues, and the remaining 2% of cells discharged equally after both types of cue. Neurons active after instructional cues were further analysed for stimulus and movement effects. During movement preparation, the activity of the vast majority of striatal cells (putamen, 81%; caudate, 76%) varied significantly when different stimuli instructed the same action. Likewise, when different movements were instructed by the same stimulus, preparatory activity of a majority of cells (putamen, 92%; caudate, 82%) changed. Consequently, a substantial proportion of cells showed combined stimulus and movement effects. Comparison of these neuronal properties with those of the dorsal premotor cortex showed significantly higher proportions of cells in the striatum whose activity reflected sensory or sensorimotor processing. These results suggest that the basal ganglia are involved in shifting attentional set and in high-order processes of movement initiation, including the linking of sensory information with behavioural responses.

Animals↗

PubMed2001

The role of the hippocampus in trace conditioning: temporal discontinuity or task difficulty?

It is well established that the hippocampal formation is critically involved in the acquisition of trace memories, a paradigm in which the conditioned (CS) and unconditioned stimuli (US) are separated by a temporal gap (Solomon et al., 1986). The structure is reportedly not critical for the acquisition of delay memories, where the CS and the US overlap in time (Berger & Orr, 1983; Schmaltz & Theios, 1972). Based on these results, it is often stated that the hippocampus is involved in "filling the gap" or otherwise associating the two stimuli in time. However, in addition to the presence of a temporal gap, there are other differences between trace and delay conditioning. The most apparent difference is that animals require many more trials to learn the trace task, and thus it is inherently more difficult than the delay task. Here, we tested whether the hippocampus was critically involved in delay conditioning, if it was rendered more difficult such that the rate of acquisition was shifted to be analogous to trace conditioning. Groups of rats received excitotoxic lesions to the hippocampus, sham lesions or were left intact. Using the same interstimulus intervals (ISI), control animals required more trials to acquire the trace than the delay task. As predicted, animals with hippocampal lesions were impaired during trace conditioning but not delay conditioning. However, when the delay task was rendered more difficult by extending the ISI (a long delay task), animals with hippocampal lesions were impaired. In addition, once the lesioned animal learned the association between the CS and the US during delay conditioning, it could learn and perform the trace CR. Thus, the role of the hippocampus in classical conditioning is not limited to learning about discontiguous events in time and space; rather the structure can become engaged simply as a function of task difficulty.

Animals↗

PubMed2005

Swedish child health care in a changing society.

BACKGROUND: Staff in Swedish child health care today feel a gap between policy and practice. By revealing the main lines in the development of child health care, we hoped to achieve a better understanding of the current trends and problems in today's Swedish child health care. METHODS: A selection of official documents about the development of child health care during the period 1930-2000 was studied with the aid of discourse analysis. RESULTS: Four discourses were identified, which serve as a foundation for a periodization of the development of child health care. In the first period the main task of child health care, alongside checking on the development of the child, was to inform and educate the mothers. During the second period health supervision became the crucial task, to identify risks and discover abnormalities and disabilities. The third period focused on the discussion concerning the identification of health-related and social 'risk groups', and the work of child health care was increasingly geared to supervision of the parents' care of their children. Parents were to be given support so that they could cope with their difficulties by themselves. During the current period child health care is increasingly expected to direct its work towards the child's surroundings and the family as a whole and is now explicitly defined as an institution that should strengthen parents' self-esteem and competence. The level of responsibility for the child's health changed gradually during the different periods, from public responsibility to parental responsibility. The focus of efforts in child health care was changed from being general in the first and second periods to general and selective in period three, and then gradually becoming selective again in period four. While control of the child's physical health was central during the first two periods, psychosocial health came into focus in the last two, along with the importance of supporting the parents to enable them to handle their difficulties by themselves. CONCLUDING REMARKS: We noted that it was difficult to translate policy recommendations into practice. One reason was the shifting focus in child health care from the child's physical health to psychosocial problems which in itself meant a shift from descriptions of concrete and well-defined duties to more abstract and general descriptions of tasks which are by definition open to interpretation. Another reason for the noted difficulty was the transition from unambiguously described measures in terms of paternalistic regulation to more participatory and at the same time more expansive definitions of roles and responsibilities.

Adaptation, Psychological↗

PubMed2001

Adaptive eye movements induced by cross-axis pursuit--vestibular interactions in trained monkeys.

We showed previously that smooth pursuit training combined with whole-body rotation in the orthogonal plane induces adaptive cross-axis vestibulo-ocular reflex (VOR). To gain an insight into the possible pathways and the nature of error signals for cross-axis VOR adaptation, we examined further properties of adaptive responses. In the first series, we trained monkeys for vertical pursuit during sinusoidal yaw rotation at 0.5 Hz (+/- 10 degrees) by presenting a target spot either in phase with, or with phase shifts (lead or lag) of 90 degrees to, the chair for 1 h. After training, sinusoidal or trapezoidal yaw rotation was tested in complete darkness without a target. Different training conditions resulted in different amounts of phase shift in cross-axis VOR. Trapezoidal yaw rotation (peak acceleration approximately 780 degrees/s2) revealed further differences in the direction, latency and time course of the adaptive responses depending on the conditions of the pursuit task. At least two (fast and slow) components with different latencies were induced in the cross-axis VOR by trapezoidal rotation after in-phase and phase-shift training. Adaptive responses were accurately simulated by the weighted sum of these two components. In the second series, we examined the effects of sequentially flashed (10 microseconds) targets in the horizontal plane during pitch rotation. The monkeys learned to track such targets by smooth pursuit, and cross-axis VOR was also induced after such apparent motion stimuli without retinal slip of the target image. These results indicate the importance of eye velocity for cross-axis VOR and suggest that this adaptation occurs most probably in the smooth pursuit pathways.

Adaptation, Physiological↗

PubMed2006

Improving alertness and performance in emergency department physicians and nurses: the use of planned naps.

STUDY OBJECTIVE: We examine whether a 40-minute nap opportunity at 3 AM can improve cognitive and psychomotor performance in physicians and nurses working 12-hour night shifts. METHODS: This is a randomized controlled trial of 49 physicians and nurses working 3 consecutive night shifts in an academic emergency department. Subjects were randomized to a control group (no-nap condition=NONE) or nap intervention group (40-minute nap opportunity at 3 AM=NAP). The main outcome measures were Psychomotor Vigilance Task, Probe Recall Memory Task, CathSim intravenous insertion virtual reality simulation, and Profile of Mood States, which were administered before (6:30 PM), during (4 AM), and after (7:30 AM) night shifts. A 40-minute driving simulation was administered at 8 AM and videotaped for behavioral signs of sleepiness and driving accuracy. During the nap period, standard polysomnographic data were recorded. RESULTS: Polysomnographic data revealed that 90% of nap subjects were able to sleep for an average of 24.8 minutes (SD 11.1). At 7:30 AM, the nap group had fewer performance lapses (NAP 3.13, NONE 4.12; p<0.03; mean difference 0.99; 95% CI: -0.1-2.08), reported more vigor (NAP 4.44, NONE 2.39; p<0.03; mean difference 2.05; 95% CI: 0.63-3.47), less fatigue (NAP 7.4, NONE 10.43; p<0.05; mean difference 3.03; 95% CI: 1.11-4.95), and less sleepiness (NAP 5.36, NONE 6.48; p<0.03; mean difference 1.12; 95% CI: 0.41-1.83). They tended to more quickly complete the intravenous insertion (NAP 66.40 sec, NONE 86.48 sec; p=0.10; mean difference 20.08; 95% CI: 4.64-35.52), exhibit less dangerous driving and display fewer behavioral signs of sleepiness during the driving simulation. Immediately after the nap (4 AM), the subjects scored more poorly on Probed Recall Memory (NAP 2.76, NONE 3.7; p<0.05; mean difference 0.94; 95% CI: 0.20-1.68). CONCLUSION: A nap at 3 AM improved performance and subjective report in physicians and nurses at 7:30 AM compared to a no-nap condition. Immediately after the nap, memory temporarily worsened. The nap group did not perform any better than the no-nap group during a simulated drive home after the night shift.

Automobile Driving↗

PubMed1996

A computer-aided comparative study of progressive alertness changes in nurses working two different night-shift rotas.

Two groups of nurses were investigated during the course of two different types of night-shift rota. The purpose was to define, if possible, the optimum shift pattern for hospital night staff. The mental alertness of two groups of nurses was assessed, both subjectively and objectively, at the beginning and end of each night-shift of a set of nights being worked. Alertness was assessed subjectively by means of a visual analogue scale, and objectively by means of a computer generated test, the unprepared simple reaction time task. One group worked permanent nights and the other rapidly rotating nights. Subjectively the nurses felt they were more alert at the beginning than at the end of a night-shift, and also at the beginning of a span of nights than at the end. With computer testing, performance was broadly worse at the beginning of a shift than at the end. It was worse at the beginning of a span of nights, improving to a peak at around the fourth day, and then in the case of permanent nights, remaining about the same or deteriorating slightly towards the end of the span. The improvement by day 4 could be a practice effect or it may be that it takes this long to adjust to the new pattern of working as some authors have described. Debate centres around whether nurses should cease working nights just as they have become accustomed to them as in the rapid rotation, or continue for longer to gain benefit from this acclimatization as in permanent nights.

Analysis of Variance↗

PubMed2001

Normal fMRI brain activation patterns in children performing a verb generation task.

Although much is known concerning brain-language relations in adults, little is known about how these functions might be represented during the developmental period. We report results from 17 normal children, ages 7-18 years, who have successfully completed a word fluency paradigm during functional magnetic resonance imaging at 3 Tesla. Regions of activation replicate those reported for adult subjects. However, a statistically significant association between hemispheric lateralization of activation and age was found in the children. Specifically, although most subjects at all ages showed left hemisphere dominance for this task, the degree of lateralization increased with age. This study demonstrates that fMRI can reveal developmental shifts in the pattern of brain activation associated with semantic language function.

Adolescent↗