Showing papers on "Motor imagery published in 1995"
TL;DR: It is proposed that motor images are endowed with the same properties as those of the (corresponding) motor representations, and therefore have the same functional relationship to the imagined or represented movement and the same causal role in the generation of this movement.
1,037 citations
TL;DR: It is concluded that mental imagery is realized at intermediate-to-high order, modality-specific cortical systems, but does not require primary cortex and is not constrained to the perceptual systems of the presented stimuli.
Abstract: Positron emission tomography (PET) can be used to map brain regions that are active when a visual object (for example, a hand) is discriminated from its mirror form. Chronometric studies suggest that viewers 'solve' this visual shape task by mentally modelling it as a reaching task, implicitly moving their left hand into the orientation of any left-hand stimulus (and conversely for a right-hand stimulus). Here we describe an experiment in which visual and somatic processing are dissociated by presenting right hands to the left visual field and vice versa. Frontal (motor), parietal (somatosensory) and cerebellar (sensorimotor) regions similar to those activated by actual and imagined movement are strongly activated, whereas primary somatosensory and motor cortices are not. We conclude that mental imagery is realized at intermediate-to-high order, modality-specific cortical systems, but does not require primary cortex and is not constrained to the perceptual systems of the presented stimuli.
681 citations
TL;DR: The mapping of brain activity during motor imagery discloses a pattern of activation similar to that of an executed action.
454 citations
TL;DR: The chronometry of imagined and actual movements was investigated in a patient with a unilateral lesion of the motor cortex, finding that common cerebral motor representations are activated when imaging and planning voluntary movements.
Abstract: The chronometry of imagined and actual movements was investigated in a patient with a unilateral lesion of the motor cortex. Motor imagery generated highly accurate estimates of motor performance in a variety of situations, reflecting the hypokinesia of the contralesional hand. There were parallel increases in mental and actual movement times from proximal to distal limb segments. Bimanual movements adopted the slower speed of the impaired hand in both conditions. Imagined motor sequences to the beat of a metronome predicted the maximum speed reached in actual performance. Finally, visually guided pointing showed the same target-size effects in the imagery and movement conditions. The results are in agreement with the hypothesis that common cerebral motor representations are activated when imaging and planning voluntary movements.
261 citations
TL;DR: The question of whether motor imagery is primarily perceptual or motoric in character does not have a simple neurophysiological answer due to the highly distributed nature of motor control, and some of the key mechanisms serving both spatial and motoric components have been provisionally identified.
221 citations
TL;DR: Data support two related hypotheses: (a) Motor sequence imagery and execution share common neural structures and (b) the frontostriatal system is among these shared structures.
211 citations
TL;DR: This special issue is devoted to recent work on mental imagery, and illustrates that imagery plays an important role in memory and spatial reasoning, but as the authors shall see, these functions merely scratch the surface.
200 citations
TL;DR: Tentative links between brain processes and cognitive theories are beginning to emerge in the authors' quest to understand memory, and a better description of memory could be 'the ability to retain and utilize acquired information or knowledge'.
168 citations
TL;DR: Brain mapping techniques were used to investigate the topographical distribution of electroencephalographic activity accompanying visual and motor imagery in four different tasks and revealed that alpha power was attenuated in vivid images during visual imagery, but enhanced during motor imagery.
Abstract: Brain mapping techniques were used to investigate the topographical distribution of electroencephalographic (EEG) activity accompanying visual and motor imagery in four different tasks. Participants were selected for their self-reported vivid or non-vivid imagery using the Vividness of Visual Imagery Questionnaire (VVIQ) and the Vividness of Movement Imagery Questionnaire (VMIQ). Topographical maps of EEG activation revealed that alpha power was attenuated in vivid images during visual imagery, particularly in the left posterior quadrant of the cortex, but enhanced during motor imagery. The imagery vividness variable interacted with experimental condition or with experimental condition and location in all four tasks. Because demand characteristics and instrument artifacts can be eliminated as possible explanations of the results, these data provide strong evidence of the construct validity of the VVIQ and VMIQ as measures of visual and motor imagery experience.
84 citations
TL;DR: Future studies of imagery and hypnotizability should make use of better measures of vividness of mental imagery and consider the relevance of aspects of imagery other than vividness, as well as search for significant nonlinear relationships with hypnotIZability.
Abstract: Two studies investigated the relationship between mental imagery and hypnotizability, with the imagery measures administered in a hypnotic context. The correlation of hypnotizability with vividness of imagery was significant in one study, but not in the other; both correlations were significantly lower than that obtained between hypnotizability and absorption, assessed in the same samples. The correlations with control of visual imagery, and with various measures of the vividness of motor imagery, were even lower and rarely significant. Except for an aggregate index of motor imagery, a search for significant nonlinear relationships with hypnotizability yielded nothing that was consistent across studies. Future studies of imagery and hvpnotizability should make use of better measures of vividness of mental imagery and consider the relevance of aspects of imagery other than vividness.
Journal Article•
TL;DR: Results suggest that visual imagery and visual perception rely on the same neural substrate, and evidence that motor imagery and motor control share some modality specific neural representations are clearly supported by tomographic measurements of cerebral blood flow.
Book•
01 Jan 1995
TL;DR: Learning and memory: the efficacy of imagery mnemonics in memory remediation, and varieties of visual representation - how are the authors to analyze the concept of mental image.
Abstract: Introduction - perspectives on the cognitive neuroscience of mental imagery, SM Kosslyn et al Part 1 Learning and memory: the efficacy of imagery mnemonics in memory remediation, JTE Richardson memory for different kinds of mental images - role of contextual and autobiographic variables, R De Beni and F Pazzaglia Part 2 Perception and action: imagery without perception - a case study of anosognosia for cortical blindness, G Goldenberg et al preserved visual imagery in visual form agnosia, P Servos and M Goodale motor imagery - perception or action?, J Annett mental imagery in the motor context, M Jeannerod the role of subvocalization in auditory imagery, D Smith et al Part 3 Information processing: current issues in the neuropsychology of image generation, MJ Farah generating visual mental images - deficits after brain damage, C Stangalino et al two types of image generation - evidence for left- and right-hemisphere processes, SM Kosslyn et al mental scanning of visual images generated from verbal descriptions - towards a model of image accuracy, M Denis et al the mental and the neural - psychological and neural studies of mental rotation and memory scanning, AP Georgopolous and G Pellizer Part 4 Reasoning: visuospatial working memory - structures and variables affecting a capacity measure, T Vecchi et al analogical representation and language structure, G Geminiani et al Afterword - varieties of visual representation - how are we to analyze the concept of mental image?, L Cooper
TL;DR: The structure that cognitive neuropsychological models may provide in different portions of the rehabilitation process is considered and it is found that this approach, when applied with methodological rigor, has practical implications for practice in aphasia assessment and treatment.
Abstract: Recently, researchers have advocated the use of cognitive neuropsychological models as an infrastructure for efforts in language rehabilitation. In this approach, clinicians characterize language impairments in individual patients with respect to cognitive models of lexical and sentence processing. This approach contrasts with many earlier efforts in which evaluation and treatment focused on the presence or absence of aphasia viewed as a general language impairment, or on syndromes of aphasia. We consider the structure that cognitive neuropsychological models may provide in different portions of the rehabilitation process and find that this approach, when applied with methodological rigor, has practical implications for practice in aphasia assessment and treatment. In turn, some hope that data derived from clinical applications with this approach may support the modification of cognitive neuropsychological models.