Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “IMAGINATION”

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 163 records · Page 9Linked to original sources
PubMed2003

Imagined viewer and object rotations dissociated with event-related FMRI.

Human spatial reasoning may depend in part on two dissociable types of mental image transformations: object-based transformations, in which an object is imagined to move in space relative to the viewer and the environment, and perspective transformations, in which the viewer imagines the scene from a different vantage point. This study measured local brain activity with event-related fMRI while participants were instructed to either imagine an array of objects rotating (an object-based transformation) or imagine themselves rotating around the array (a perspective transformation). Object-based transformations led to selective increases in right parietal cortex and decreases in left parietal cortex, whereas perspective transformations led to selective increases in left temporal cortex. These results argue against the view that mental image transformations are performed by a unitary neural processing system, and they suggest that different overlapping systems are engaged for different image transformations.

Adolescent↗
PubMed1999

Activation of cortical and cerebellar motor areas during executed and imagined hand movements: an fMRI study.

Brain activation during executed (EM) and imagined movements (IM) of the right and left hand was studied in 10 healthy right-handed subjects using functional magnetic resonance imagining (fMRI). Low electromyographic (EMG) activity of the musculi flexor digitorum superficialis and high vividness of the imagined movements were trained prior to image acquisition. Regional cerebral activation was measured by fMRI during EM and IM and compared to resting conditions. Anatomically selected regions of interest (ROIs) were marked interactively over the entire brain. In each ROI activated pixels above a t value of 2.45 (p<0.01) were counted and analyzed. In all subjects the supplementary motor area (SMA), the premotor cortex (PMC), and the primary motor cortex (M1) showed significant activation during both EM and IM; the somatosensory cortex (S1) was significantly activated only during EM. Ipsilateral cerebellar activation was decreased during IM compared to EM. In the cerebellum, IM and EM differed in their foci of maximal activation: Highest ipsilateral activation of the cerebellum was observed in the anterior lobe (Larsell lobule H IV) during EM, whereas a lower maximum was found about 2-cm dorsolateral (Larsell lobule H VII) during IM. The prefrontal and parietal regions revealed no significant changes during both conditions. The results of cortical activity support the hypothesis that motor imagery and motor performance possess similar neural substrates. The differential activation in the cerebellum during EM and IM is in accordance with the assumption that the posterior cerebellum is involved in the inhibition of movement execution during imagination.

Adult↗
PubMed1980

Imaginal vs perceptual scanning of a visual representation.

Imaginal and perceptual scanning were compared to determine whether the reaction time function obtained during imaginal scanning in previous studies is analogous to what would happen in the perceptual situation. Subjects scanned arrays of four digits which were either imagined of physically present. Monotonic increases in reaction time as a function of distance were found in both cases. However, the zero intercept of the reaction times was significantly faster for the perceptual scanning group, probably due to the easier access to the loci. The over-all similarity in the results might suggest that a common structure is employed to represent information from imaginal and perceptual sources.

Distance Perception↗
PubMed1989

Relationship between imaginative play and language development in hearing-impaired children.

The relationship between imaginative play and language development was investigated in a group of 20 severely and profoundly hearing-impaired children between the ages of 3 and 6. Each child was videotaped in a 60-minute session interacting with the investigator and playing with three sets of toys: a miniature house, barn, and garage. Analysis of the subjects' language revealed that 15 were operating in Brown's (1973) Stage 1, one in Stage 3, and four in Stage 5. Play was analyzed along three dimensions: (a) percentage of time engaged in imaginative play; (b) use of planned pretend; and (c) use of story line. A significant relationship was found between imaginative play and language development. Results revealed no relationship between imaginative play and chronological age. Correspondences were found between language development and use of planned pretend and story line.

Age Factors↗
PubMed2003

Egocentric organization of spatial activities in imagined navigation.

Studies on spatial frameworks suggest that the way we locate objects in imagined environments is influenced by the physical and functional properties of the world and our body. The present study provides evidence that such an influence also characterizes imagined navigation. In Experiment 1, participants followed spatial directions to construct an imagined path, while either keeping constant or updating their orientation at each step. A pattern of step times diagnostic of spatial frameworks was obtained in the updated-orientation but not in the constant-orientation condition. In Experiment 2, participants performed the updated-orientation condition with two levels of external support for the reference frame being used. Step times conformed to the predictions of spatial frameworks in both conditions. Both experiments also provided support that the processes involved in imagined navigation exhibit the operator-operand dynamics of other mental skills previously documented in the mental arithmetic domain. These results reinforce Piaget's (1954) notion that spatial displacements and integer arithmetic share a set of structural characteristics

Female↗
PubMed2001

An fMRI study of imagined self-rotation.

In the present study, functional magnetic resonance imaging was used to examine the neural mechanisms involved in the imagined spatial transformation of one's body. The task required subjects to update the position of one of four external objects from memory after they had performed an imagined self-rotation to a new position. Activation in the rotation condition was compared with that in a control condition in which subjects located the positions of objects without imagining a change in self-position. The results indicated similar networks of activation to other egocentric transformation tasks involving decisions about body parts. The most significant area of activation was in the left posterior parietal cortex. Other regions of activation common among several of the subjects were secondary visual, premotor, and frontal lobe regions. These results are discussed relative to motor and visual imagery processes as well as to the distinctions between the present task and other imagined egocentric transformation tasks.

Adult↗
PubMed1998

Virtual reality and imaginative techniques in clinical psychology.

The great potential offered by Virtual Reality (VR) derives prevalently from the central role, in psychotherapy, occupied by the imagination and by memory. These two elements, which are fundamental in the life of every one of us, present absolute and relative limits to individual potential. Thanks to virtual experiences, it is possible to transcend these limits. The re-created world may at times be more vivid and real than the one that most subjects are able to describe through their own imagination and through their own memory. This chapter focuses on imaginative techniques to find new ways of applications in therapy. In particular the chapter analyses in which way VR can be used to improve the efficacy of current techniques. VR produces a change with respect to the traditional relationship between client and therapist. The new configuration of this relationship is based on the awareness of being more skilled in the difficult operations of recovery of past experiences, through the memory, and of foreseeing of future experiences, through the imagination. At the same time, the subject undergoing treatment perceives the advantage of being able to re-create and use a real experiential world within the walls of the clinical office of his own therapist.

Computer Simulation↗
PubMed2000

Story-telling ability in children with autism or Asperger syndrome: a window into the imagination.

BACKGROUND: Autism spectrum conditions are diagnosed on the basis of impaired imagination. The present study used a totally free story-telling method to assess if narratives produced by children with autism or Asperger Syndrome (AS) contained fewer imaginative events. METHOD: In Condition 1, children were offered an imaginary theme and asked to elaborate a story. In Condition 2, they were offered a reality-based theme with the same instructions. Comparison groups included 13 children with autism, 14 children with AS, 15 children with moderate learning difficulties (MLD), and 14 normally developing children. The non-autistic controls had a verbal mental age (VMA) either equivalent or lower than the autism and AS groups. RESULTS: Both the children with autism and AS were less likely to introduce imaginary elements into their stories in Condition 2, though the children with AS were more able to produce imaginative narratives than children with autism in Condition 1. CONCLUSIONS: This study provides experimental evidence for imaginative impairments in story-telling in children with autism spectrum conditions. These are discussed in terms of two cognitive theories: executive dysfunction and theory of mind. LIMITATIONS: In this study it was not possible to match the children with autism and AS with each other on VMA, as the children with autism were not as high-functioning. Future research could examine VMA matched groups of autism and AS.

Asperger Syndrome↗
PubMed1995

Young children's understanding of fictional versus epistemic mental representations: imagination and belief.

In 2 studies, 3- and 4-year-old children's ability to reason about the relation between mental representations and reality was examined. In the first study, children received parallel false belief and "false" imagination tasks. Results revealed that children performed better on imagination tasks than on belief tasks. The second study demonstrated that, when various alternative explanations for better performance on the imagination task were controlled for, children still performed significantly better when reasoning about another person's imagination than when reasoning about another person's belief. These findings suggest that children's understanding that mental representations can differ from reality may emerge first with respect to representations that do not purport to represent reality truthfully.

Child Development↗
PubMed2005

Constitutive expression of heat shock protein p23 correlates with proneural territories in imaginal discs of Drosophila melanogaster.

2-DE followed by MALDI-TOF was used to purify and identify a Drosophila protein (catalogued as SSP 6002) that showed marked differences in the level of expression in the different imaginal discs of third instar larvae. Fingerprinting showed that the spot of interest was the heat shock 23 polypeptide (hsp23). We characterized the kinetics of its induction by heat shock in wing imaginal discs and raised an antiserum against the denatured protein, which recognizes a single unphosphorylated spot on 2-D gels. The difference in its expression in discs was corroborated by analyzing its level in the imaginal discs of postbithorax mutants. We also investigated the developmental expression of hsp23 in imaginal discs with antiserum raised against the native protein. Its spatial and temporal pattern of expression is related to the proneural territories and maintained even under heat shock conditions. In addition, its pattern of expression is regulated by transcription factors and signaling pathways (notch and epidermal growth factor receptor) involved in proneural specification.

Amino Acid Sequence↗
PubMed1993

Identification of Drosophila wing imaginal disc proteins by two-dimensional gel analysis and microsequencing.

We have combined high-resolution two-dimensional (2D) gel electrophoresis with microsequencing techniques in order to identify proteins in the 2D gel database of wing imaginal discs of Drosophila melanogaster. First, a high-resolution 2D gel separation pattern of the [35S]methionine-labeled polypeptides from CME W2 cells, a stable cell line derived from wing imaginal discs, is presented and compared with the standard pattern of polypeptides of wing imaginal discs. These studies reveal significant qualitative and quantitative alterations in polypeptide expression between both samples. Second, we carried 2D PAGE to the preparative level using the CME W2 cell line mixed with radioactively labeled wing imaginal discs in order to identify some common polypeptides and subsequently characterized them by microsequencing techniques. Using these methods we obtained partial amino acid sequences of several Drosophila proteins of the 2D gel protein database. As an illustration we present 12 of them: 8 corresponding to proteins already known in Drosophila and the 4 showing homologies with proteins of other organisms.

Amino Acid Sequence↗
PubMed2001

Ectopic expression of BEAF32A in the Drosophila eye imaginal disc inhibits differentiation of photoreceptor cells and induces apoptosis.

Transgenic flies were established in which ectopic expression of boundary element-associated factor (BEAF) 32A was targeted to the Drosophila eye imaginal disc. The eyes of the adult fly displayed a severe rough eye phenotype. When these eyes were sectioned, most ommatidia were found to be fused and irregularly shaped rhabdomeres were observed. In the developing eye imaginal disc, expression of BEAF32A inhibited differentiation of photoreceptor cells. Expression of BEAF32A also induced extensive apoptosis of eye imaginal disc cells and, consistent with this, co-expression of baculovirus P35 in the eye imaginal disc suppressed the BEAF32A-induced rough eye phenotype. To investigate the effects of BEAF32A on regulation of chromatin structure, genetic crosses of the BEAF32A-overexpressing flies with loss-of-function mutants for genes encoding other boundary element-binding factors or regulators of chromatin structure were conducted. Interestingly, half-dose reduction of the su(Hw) gene strongly enhanced the rough eye phenotype induced by BEAF32A. Furthermore, genetic crosses of the transgenic flies with loss-of-function mutants for genes interacting with Polycomb revealed specific links between BEAF32A and genes such as Distalless and kohtalo, suggesting a relation to the chromatin insulator function of BEAF. In addition, genetic crosses of transgenic flies expressing BEAF32A with a collection of Drosophila deficiency stocks allowed us to identify several genomic regions, deletions of which caused enhancement or suppression of the BEAF32A-induced rough eye phenotype. The transgenic flies established in this study should be useful to identify targets of BEAF32A and its positive or negative regulators in Drosophila.

Animals↗
PubMed1998

patufet, the gene encoding the Drosophila melanogaster homologue of selenophosphate synthetase, is involved in imaginal disc morphogenesis.

Proliferation in imaginal discs requires cell growth and is linked to patterning processes controlled by secreted cell-signalling molecules. To identify new genes involved in the control of cell proliferation we have screened a collection of P-lacW insertion mutants that result in lethality in the larval/pupal stages, and characterized a novel gene, patufet (ptuf). Inactivation of ptuf by a P element insertion in the 5' untranslated region leads to aberrant imaginal disc morphology characterized by a reduction in mass of discs and disorganization of disc cells where no folding or patterning can be detected. Moreover, apoptotic cells can be observed in these small and abnormal mutant discs. To examine the role of ptuf we have studied its clonal behaviour in genetic mosaics generated by mitotic recombination. The mutation causes reduced cell viability, smaller cell size and stops vein differentiation. Non-autonomous effects, such as abnormal differentiation of wild-type cells surrounding the clones, are also observed. We have cloned the ptuf gene of Drosophila melanogaster and found that it encodes a selenophosphate synthetase, which is the first identified in insects. Mutant flies transformed with the full-length cDNA show complete reversion of lethality and disc phenotype. Northern blot analysis and in situ hybridization indicate that the ptuf gene is expressed in imaginal discs as well as at different stages of development. The synthesis of selenoproteins by the selenophosphate synthetase, the role of selenoproteins in the maintenance of the oxidant/antioxidant balance of the cell and its possible implications in imaginal disc morphogenesis are discussed.

Amino Acid Sequence↗
PubMed1989

Allelic interactions at the engrailed locus of Drosophila: engrailed protein expression in imaginal discs.

Many embryonic lethal engrailed (enlethal) mutations are known to partially complement the cuticular defects of the original engrailed mutation, en1. To explore the nature of this complementation, the adult phenotypes of several different en1/enlethal transheterozygotes were compared with the corresponding patterns of engrailed protein expression in third larval instar imaginal discs (determined by immunofluorescence). Transheterozygotes of en1 and deletions of the locus (enDf) typically show slight complementation in the adult cuticle. The pattern of engrailed protein expression in some en1/enDf wing discs is indistinguishable from en1 homozygotes, but in others the pattern is nearly normal. en1/enDf leg discs appear to express engrailed protein normally. Transheterozygotes of en1 and EMS-induced, cytologically normal enlethal alleles have almost normal adult cuticle phenotypes and also exhibit normal patterns of engrailed protein expression in all of the thoracic imaginal discs. Surprisingly, the intensity of anti-engrailed staining in these discs is elevated relative to that in wild type. en2 is an unusual lethal allele in that it does not complement either the en1 adult cuticle phenotype or the protein expression pattern in imaginal discs. Moreover, the cytologically normal enlethal alleles also complement en2, at least partially. Both wing and leg imaginal discs from en2/enlethal transheterozygotes show abnormal patterns of engrailed protein expression. These results are discussed in the context of an autoregulatory model for engrailed regulation.

Alleles↗
PubMed1992

What are and what are not imaginal discs: reevaluation of some basic concepts (Insecta, Holometabola).

Some general aspects of the concept of imaginal discs in the Holometabola are reevaluated. Their monolayer character and continuity with the surrounding epidermis are confirmed. Studies on the imaginal discs of the silkworm (Bombyx mori) and data from the literature show that the discs and their peripodial cells produce cuticle during larval life, as well as at metamorphosis. In B. mori it is demonstrated that adult and larval antennae are produced by the same cells or their progeny. The results also suggest that segments of the typically three-segmented larval antenna of Holometabola are not scape, pedicel, and one-segmented flagellum; at least segments 2 and 3 are of flagellar origin. Based on these and some additional facts it is argued that: (1) No larval organs are "replaced" at metamorphosis, but strict "sequential homology" is always maintained. (2) Imaginal discs are not undifferentiated structures destined to form the adult after larval breakdown, cannot be unambiguously defined, and do not represent qualitatively different epidermal structures. Classical imaginal discs (invaginated and present also in pre-final larval instars) arose several times independently and were not present in the larvae of ancestral Holometabola. (3) Since the disc cells are not undifferentiated and "embryonic" (if these words have a defined meaning at all), it is unreasonable to expect that the processes taking place in discs at metamorphosis would differ fundamentally from those occurring in other diploid metamorphosing epidermal cells.

Animals↗
PubMed1977

Patterns of protein synthesis in imaginal discs of Drosophila melanogaster.

Patterns of polypeptide synthesis in wing, leg and eye-antenna imaginal discs and in whole larvae of wild-type and and mutant Drosophila melanogaster have been examined using two-dimensional polyacrylamide gel electrophoresis and autoradiography. After 2 hr of labeling with 35S during the third larval instar, the synthesis of more than 318 polypeptides has been detected in imaginal discs. Of these, 268 are present in similar amounts in all three disc types. The remaining polypeptides detected in the three imaginal disc types fall into two categories: those unique to a particular disc type, and those specific for a particular pair of disc types. These results are discussed in relation to the spectrum of gene expression in imaginal discs.

Animals↗
PubMed1990

Dynamics of central nervous activation during motor imagination.

Central nervous processes of sensorimotor and behaviour control are prerequisites of skills and motor performance. Eight students (Ss) in sports were tested during motor imagination. They were requested to imagine their own movements when swimming over a distance of 100 m (sitting in a resting position, without any real or imitated movements). Electroencephalograms (EEG), heart rate (HR), skin conductance (SC), and respiration rate (RR) were recorded before, during and after one series of 3 periods of mental training (MT). HR, RR and SC increased during MT. The highest level of SC can be found at the beginning of the first period of imagination. Mean alpha-frequency of the EEG over the left occipital and precentral area in all Ss was higher during MT. The degree of these changes varied during the 3 imagination periods.

Brain↗
PubMed2004

Invasive cell behavior during Drosophila imaginal disc eversion is mediated by the JNK signaling cascade.

Drosophila imaginal discs are monolayered epithelial invaginations that grow during larval stages and evert at metamorphosis to assemble the adult exoskeleton. They consist of columnar cells, forming the imaginal epithelium, as well as squamous cells, which constitute the peripodial epithelium and stalk (PS). Here, we uncover a new morphogenetic/cellular mechanism for disc eversion. We show that imaginal discs evert by apposing their peripodial side to the larval epidermis and through the invasion of the larval epidermis by PS cells, which undergo a pseudo-epithelial-mesenchymal transition (PEMT). As a consequence, the PS/larval bilayer is perforated and the imaginal epithelia protrude, a process reminiscent of other developmental events, such as epithelial perforation in chordates. When eversion is completed, PS cells localize to the leading front, heading disc expansion. We found that the JNK pathway is necessary for PS/larval cells apposition, the PEMT, and the motile activity of leading front cells.

Animals↗