Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Imitative Behavior”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed2007

Subtle imitation behaviour in convenience samples of normal, demented, and currently depressed elderly subjects.

BACKGROUND: The clinical significance of imitation behaviour (IB) is unclear. The aim of this study was to investigate the prevalence of subtle naïve and obstinate IB in convenience samples of normal elderly, demented, and depressed subjects. METHOD: Subtle IB was assessed using a protocol constructed ad hoc in 146 patients, consecutively referred to a memory clinic having received an ICD-10 diagnosis of either dementia or depression, and in 241 healthy subjects. The prevalence of IB in the three groups was determined and the association with possible demographic, cognitive, and non-cognitive variables analysed. RESULTS: Subtle naïve IB was frequent in the elderly with dementia, intermediate in the depressed, and rare in the normal elderly except that the latter frequently stretched out their arms. Obstinate IB never occurred in the normal elderly. IB was predicted by none of the variables used. LIMITATIONS: The groups included were convenience samples with the depressed being a small group precluding further distinction of depressive subtypes. CONCLUSION: Although naïve IB is a frequent clinical feature in the demented, it also accompanies depressive disorders in the elderly. It can be observed as context-specific IB in the normal elderly. Obstinate IB does not occur in the normal elderly.

Aged↗
PubMed2006

Variability of EEG synchronization prior to and during observation and execution of a sequential finger movement.

The aim of this study was to test the validity of mirror neuron activity in humans through analysis of electroencephalographic (EEG) functional connectivity during an action not directed towards an object. We investigated changes in EEG interchannel synchronization prior to and during action execution and also prior to and during observation of the same action. Twelve participants observed a simple finger movement sequence. In a second testing session they physically executed the movement. EEGs were recorded from 19 active sites across the cortex. Activity was considered in four frequency bands (7-10 Hz, 10-13 Hz, 13-20 Hz, and 20-30 Hz) using a new measure: synchronization likelihood. This technique considers rapid changes in signal synchronization and spatiotemporal patterns of coherence. The results revealed no statistically significant difference in synchronization likelihood between the observation and execution data. We found an increase in synchronization over a broad frequency range during task processing and suggest that this may reflect interregional cortical coupling of intricately and hierarchically interconnected networks that are active in a similar way during both observation and execution of a movement. While EEG may be insensitive to differences present during the observation and execution of a movement, the results of the present study shed some light on the general mechanisms of cognitive integration.

Adult↗
PubMed2004

Early detection of core deficits in autism.

The goal of this review of the research literature is to discuss approaches to the early detection of autism in infancy. Early detection would enable diagnoses to be made before 18 months of age rather than at 24-30 months, the age where diagnoses start to be made now. After summarizing the criteria for a deficit to be considered "core" to the disorder, the literature on research strategies used in early detection is examined. In order to guide the design of future studies, the review then turns to an overview of what is known about the processes of early social development in typically developing children that underlie the domains in which core deficits are manifested in young children with autism. The social domains covered in the review are those that show development in typically developing infants below 18 months of age: dyadic interaction and imitation; emotion discrimination; and attachment. The review concludes that all of these areas are worthy of investigation in young children, particularly those at higher risk of showing some of the core deficits of autism such as the infant siblings of children with autism.

Affect↗
PubMed2002

Respiratory units of motor production and song imitation in the zebra finch.

Juvenile male zebra finches (Taeniopygia guttata) learn a stereotyped song by imitating sounds from adult male tutors. Their song is composed of a series of syllables, which are separated by silent periods. How acoustic units of song are translated into respiratory and syringeal motor gestures during the song learning process is not well understood. To learn about the respiratory contribution to the imitation process, we recorded air sac pressure in 38 male zebra finches and compared the acoustic structures and air sac pressure patterns of similar syllables qualitatively and quantitatively. Acoustic syllables correspond to expiratory pressure pulses and most often (74%) entire syllables are copied using similar air sac pressure patterns. Even notes placed within different syllables are generated with similar air sac pressure patterns when only segments of syllables are copied (9%). A few of the similar syllables (17%) are generated with a modified pressure pattern, typically involving addition or deletion of an inspiration. The high similarity of pressure patterns for like syllables indicates that generation of particular sounds is constrained to a narrow range of air sac pressure conditions. Following presentation of stroboscope flashes, song was typically interrupted at the end of an expiratory pressure pulse, confirming that expirations and, therefore, syllables are the smallest unit of motor production of song. Silent periods, which separate syllables acoustically, are generated by switching from expiration to inspiration. Switching between respiratory phases, therefore, appears to play a dominant role in organizing the stereotyped motor program for song production.

Acoustic Stimulation↗
PubMed2002

Brain lesions that impair vocal imitation in adult budgerigars.

Vocal imitation is a complex form of imitative learning that is well developed only in humans, dolphins, and birds. Among birds, only some species are able to imitate sounds in adulthood. Of these, the budgerigar (Melopsittacus undulatus) has been studied in most detail. Previous studies suggested that the vocal motor system in budgerigars receives auditory information from the lateral frontal neostriatum (NFl). In the present study, we confirm this hypothesis by showing that infusions of the GABA agonist muscimol into NFl reduce the strength of auditory responses in a telencephalic vocal motor nucleus, the central nucleus of the lateral neostriatum (NLc). To test whether the auditory information conveyed from NFl to NLc plays a role in vocal imitation, we lesioned parts of NFl and the overlying ventral hyperstriatum (HVl) in seven adult male budgerigars and then examined whether the lesioned males would imitate the calls of females with whom they were paired. We found that, compared to sham-lesioned controls, the lesioned birds were significantly impaired in their imitation of female calls. Yet, the lesioned males were clearly not deaf (e.g., their previously learned calls did not degrade as they do after deafening). Therefore, the data suggest that NFl/HVl lesions impair vocal imitation by reducing the amount of auditory information that reaches the vocal motor system. Interestingly, the females that were paired with lesioned males displayed more vocal plasticity than the females in the control group, and some even imitated their male's prepairing calls.

Animals↗
PubMed2002

Zero-inflated models for regression analysis of count data: a study of growth and development.

Poisson regression is widely used in medical studies, and can be extended to negative binomial regression to allow for heterogeneity. When there is an excess number of zero counts, a useful approach is to used a mixture model with a proportion P of subjects not at risk, and a proportion of 1--P at-risk subjects who take on outcome values following a Poisson or negative binomial distribution. Covariate effects can be incorporated into both components of the models. In child assessment, fine motor development is often measured by test items that involve a process of imitation and a process of fine motor exercise. One such developmental milestone is 'building a tower of cubes'. This study analyses the impact of foetal growth and postnatal somatic growth on this milestone, operationalized as the number of cubes and measured around the age of 22 months. It is shown that the two aspects of early growth may have different implications for imitation and fine motor dexterity. The usual approach of recording and analysing the milestone as a binary outcome, such as whether the child can build a tower of three cubes, may leave out important information.

Binomial Distribution↗
PubMed1993

Praxis and the right hemisphere.

We report our observations on praxis in a strongly right-handed man following a massive stroke that resulted in virtually complete destruction of the left cerebral hemisphere. Our patient was severely impaired in pantomiming transitive gestures with the left hand and in reproducing novel non-symbolic hand and arm movement sequences. However, overlearned habitual actions like actual object use and intransitive gestures were relatively spared. Performance of axial commands was intact. Gesture recognition and discrimination were also preserved. Based on these findings, we propose that the praxis system of the right hemisphere is strongly biased toward "concrete" or context-dependent execution of familiar, well-established action routines. The right hemisphere is critically dependent on transcallosal contribution from the left hemisphere for control of the left hand in "abstract" or context-independent performance of transitive movements and in learning novel movement sequences. At least in some individuals, the right hemisphere can recognize and discriminate gestures. Possible implications of our findings for the cerebral control of praxis and for recovery from apraxia are discussed.

Aphasia, Broca↗
PubMed1999

Apraxia in corticobasal degeneration.

Corticobasal degeneration (CBD) is a degenerative disease that often presents with an asymmetric progressive ideomotor limb apraxia. Some apraxic subjects may fail to perform skilled purposive movements on command because they have lost the memories or representations that specify how these movements should be performed (representational deficit). In contrast, other apraxic subjects may have the movement representations but are unable to utilize the information contained in them to execute skilled purposive movements (production-execution deficit). To learn if the apraxic deficit in CBD is induced by a representational or a production-execution deficit, we tested three nondemented subjects with CBD on tasks requiring production of meaningful or meaningless gestures to command, gesture imitation, gesture discrimination, and novel gesture learning. A fourth subject with incomplete data also is presented. The results suggest that the apraxia associated with CBD is initially induced by a production-execution defect with relative sparing of the movement representations.

Aged↗
PubMed2000

Compatibility between observed and executed finger movements: comparing symbolic, spatial, and imitative cues.

Intuitively, one can assume that imitating a movement is an easier task than responding to a symbolic stimulus like a verbal instruction. Support for this suggestion can be found in neuropsychological research as well as in research on stimulus-response compatibility. However controlled experimental evidence for this assumption is still lacking. We used a stimulus-response compatibility paradigm to test the assumption. In a series of experiments, it was tested whether observed finger movements have a stronger influence on finger movement execution than a symbolic or spatial cue. In the first experiment, we compared symbolic cues with observed finger movements using an interference paradigm. Observing finger movements strongly influenced movement execution, irrespective of whether the finger movement was the relevant or the irrelevant stimulus dimension. In the second experiment, effects of observed finger movements and spatial finger cues were compared. The observed finger movement dominated the spatial finger cue. A reduction in the similarity of observed and executed action in the third experiment led to a decrease of the influence of observed finger movement, which demonstrates the crucial role of the imitative relation of observed and executed action for the described effects. The results are discussed in relation to recent models of stimulus-response compatibility. Neurocognitive support for the strong relationship between movement observation and movement execution is reported.

Cues↗
PubMed1997

Activation without selection: parallel right hemisphere roles in language and intentional movement?

Because language and praxis each require the activation and selection of knowledge structures in long-term memory (MacKay, 1985, 1987), it is reasonable to consider whether hemisphere asymmetries for such processes span both domains. Language and skilled movement are thought to be strongly lateralized to the left hemisphere in most individuals. Yet, although recent evidence suggests that the right hemisphere also contributes to language use in context, few similar arguments have been made for the right hemisphere's involvement in motor planning. In this paper, we review some of the evidence for a right hemisphere role in language and action processing and propose that within each domain the right hemisphere activates a range of relevant knowledge structures without selection.

Affect↗
PubMed1999

Sources of flexibility in human cognition: dual-task studies of space and language.

Under many circumstances, children and adult rats reorient themselves through a process which operates only on information about the shape of the environment (e.g., Cheng, 1986; Hermer & Spelke, 1996). In contrast, human adults relocate themselves more flexibly, by conjoining geometric and nongeometric information to specify their position (Hermer & Spelke, 1994). The present experiments used a dual-task method to investigate the processes that underlie the flexible conjunction of information. In Experiment 1, subjects reoriented themselves flexibly when they performed no secondary task, but they reoriented themselves like children and adult rats when they engaged in verbal shadowing of continuous speech. In Experiment 2, subjects who engaged in nonverbal shadowing of a continuous rhythm reoriented like nonshadowing subjects, suggesting that the interference effect in Experiment 1 did not stem from general limits on working memory or attention but from processes more specific to language. In further experiments, verbally shadowing subjects detected and remembered both nongeometric information (Experiment 3) and geometric information (Experiments 1, 2, and 4), but they failed to conjoin the two types of information to specify the positions of objects (Experiment 4). Together, the experiments suggest that humans' flexible spatial memory depends on the ability to combine diverse information sources rapidly into unitary representations and that this ability, in turn, depends on natural language.

Adolescent↗
PubMed1995

Effects of experience and reminding on long-term recall in infancy: remembering not to forget.

We examined whether some of the factors that facilitate recall in older children also extend to 1- to 2-years-olds. Using elicited imitation we assessed the efficacy of verbal (Experiment 1), and verbal plus nonverbal (Experiment 2) reminding on 15-month-olds' recall after a 1-week delay. Reminding ameliorated forgetting: Performance at delayed and immediate recall was equivalent. The addition of nonverbal information did not enhance recall above verbal information alone. In Experiment 3 we investigated the influence of verbal reminding, repeated experience, and mode of experience (i.e., imitate vs watch only) on recall after 1 month. The effects of reminding depended on event type: Reminding facilitated recall of events with enabling relations, but not of events lacking them. Repeated experience and the opportunity to imitate facilitated recall; children who watched events only once nevertheless recalled them. Results suggest that the strength of organization of an event representation, rather than retention interval, is a major determinant of remembering during the second year of life.

Attention↗
PubMed1995

Long-term recall of event sequences in infancy.

The first experiment shows that 11-month-olds can encode novel causal events from a brief period of observational learning, and recall much of the information after 24 h. The second experiment, using both a longitudinal and a cross-sectional design, shows recall of the same events after a delay of 3 months. The infants remembered more individual actions than whole sequences, but reproduced many of the events in their entirety (and always in correct order) after the long delay. Although they also reproduced arbitrarily ordered events immediately after being shown them at 11 months, they began to forget them after 24 h and showed essentially no recall for this type of event after 3 months. The experiments not only indicate long-lasting memory for briefly experienced events in infancy, they also suggest that the factors that organize recall at this young age are similar to those found in older children and adults.

Association Learning↗
PubMed1995

What infant memory tells us about infantile amnesia: long-term recall and deferred imitation.

Long-term recall memory was assessed using a nonverbal method requiring subjects to reenact a past event from memory (deferred imitation). A large sample of infants (N = 192), evenly divided between 14- and 16-months old, was tested across two experiments. A delay of 2 months was used in Experiment 1 and a delay of 4 months in Experiment 2. In both experiments two treatment groups were used. In one treatment group, motor practice (immediate imitation) was allowed before the delay was imposed; in the other group, subjects were prevented from motor practice before the delay. Age-matched control groups were used to assess the spontaneous production of the target acts in the absence of exposure to the model in both experiments. The results demonstrated significant deferred imitation for both treatment groups at both delay intervals, and moreover showed that infants retained and imitated multiple acts. These findings suggest that infants have a nonverbal declarative memory system that supports the recall of past events across long-term delays. The implications of these findings for the multiple memory system debate in cognitive science and neuroscience and for theories of infantile amnesia are considered.

Attention↗
PubMed1995

Episodic memory and autonoetic consciousness: developmental evidence and a theory of childhood amnesia.

This research draws together Tulving's (1985) view on episodic memory and research on children's developing "theory of mind." Episodic memory, in its technical meaning given by Tulving, requires the autonoetic consciousness of having experienced remembered events, but developmental findings suggest that children cannot encode events as experienced before the age of about 4 or 5 years. Before this age they have insufficient understanding of what constitutes experience, specifically they do not reflect on the perceptual origin of their own knowledge. To demonstrate such a link children between 3 and 6 years were assessed for their understanding of the perceptual origin of their own knowledge on different "see-know tests," in particular a test assessing understanding that our senses inform only about certain aspects of the perceived objects. A significant association was found between passing see-know tests and free recall, which persisted even when cued recall and verbal intelligence are partialed out. These results are used to argue that between 3 to 6 years children develop the ability to remember events as experienced and that this development can explain adults' inability to have recollective experiences of childhood events before that age (childhood amnesia).

Association Learning↗
PubMed1995

The use of dolls to interview young children: issues of symbolic representation.

A very common practice in the investigation of suspected sexual abuse is to use anatomically detailed dolls to interview children. The use of such dolls is particularly advocated for very young children. For a doll to be useful, however, children must accept and use it as a representation of themselves. Our previous research on 2- and 3-year-old children's understanding of symbolic objects led us to hypothesize that such very young children might have difficulty understanding and using a doll as a self-representation. In the study reported here, 2-1/2-, 3-, and 4-year-old children played some games with an experimenter, and they were interviewed immediately afterward. The children did, as expected, have difficulty using the doll as a self-representation and mapping from themselves to the doll. As a consequence, they provided more correct information in their direct (verbal and nonverbal) responses to the interviewer's questions than they demonstrated on the doll. Implications and limitations of this research are discussed with respect to interviewing young children.

Body Image↗
PubMed2001

Mediated imitation in 6-month-olds: remembering by association.

In two experiments with 72 6-month-olds, we examined whether associating an imitation task with an operant task affects infants' memory for either task. In Experiment 1, infants who imitated target actions that were modeled for 60 s on a hand puppet remembered them for only 1 day. We hypothesized that if infants associated the puppet imitation task with a longer-remembered operant task, then they might remember it longer too. In Experiment 2, infants learned to press a lever to activate a miniature train-a task 6-month-olds remember for 2 weeks-and saw the target actions modeled immediately afterward. These infants successfully imitated for up to 2 weeks, but only if the train memory was retrieved first. A follow-up experiment revealed that the learned association was bidirectional. This is the first demonstration of mediated imitation in 6-month-olds across two very different paradigms and reveals that associations are an important means of protracting memories.

Association Learning↗