| 1. |
- Bengtsson, SL, et al.
(author)
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Cortical regions involved in the generation of musical structures during improvisation in pianists
- 2007
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 19:5, s. 830-842
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Journal article (peer-reviewed)abstract
- Studies on simple pseudorandom motor and cognitive tasks have shown that the dorsolateral prefrontal cortex and rostral premotor areas are involved in free response selection. We used functional magnetic resonance imaging to investigate whether these brain regions are also involved in free generation of responses in a more complex creative behavior: musical improvisation. Eleven professional pianists participated in the study. In one condition, Improvise, the pianist improvised on the basis of a visually displayed melody. In the control condition, Reproduce, the participant reproduced his previous improvisation from memory. Participants were able to reproduce their improvisations with a high level of accuracy, and the contrast Improvise versus Reproduce was thus essentially matched in terms of motor output and sensory feedback. However, the Improvise condition required storage in memory of the improvisation. We therefore also included a condition FreeImp, where the pianist improvised but was instructed not to memorize his performance. To locate brain regions involved in musical creation, we investigated the activations in the Improvise-Reproduce contrast that were also present in FreeImp contrasted with a baseline rest condition. Activated brain regions included the right dorsolateral prefrontal cortex, the presupplementary motor area, the rostral portion of the dorsal premotor cortex, and the left posterior part of the superior temporal gyrus. We suggest that these regions are part of a network involved in musical creation, and discuss their possible functional roles.
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| 2. |
- de Frias, Cindy M., et al.
(author)
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Catechol O-Methyltransferase Val¹-sup-5-sup-8 Met Polymorphism is Associated with Cognitive Performance in Nondemented Adults.
- 2005
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In: Journal of Cognitive Neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 17:7, s. 1018-1025
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Journal article (peer-reviewed)abstract
- The catechol O-methyltransferase (COMT) gene is essential in the metabolic degradation of dopamine in the prefrontal cortex. In the present study, we examined the effect of a Val¹-sup-5-sup-8Met polymorphism in the COMT gene on individual differences and changes in cognition (executive functions and visuospatial ability) in adulthood and old age. The participants were 292 nondemented men (initially aged 35-85 years) from a random sample of the population (i.e., the Betula study) tested at two occasions with a 5-year interval. Confirmatory factor analyses were used to test the underlying structure of three indicators of executive functions (verbal fluency, working memory, and Tower of Hanoi). Associations between COMT, age, executive functioning, and visuospatial (block design) tasks were examined using repeated-measures analyses of variance. Carriers of the Val allele (with higher enzyme activity) compared with carriers of the Met/Met genotype (with low enzyme activity) performed worse on executive functioning and visuospatial tasks. Individuals with the /Val genotype declined in executive functioning over the 5-year period, whereas carriers of the Met allele remained stable in performance. An Age × COMT interaction for visuospatial ability located the effect for middle-aged men only. This COMT polymorphism is a plausible candidate gene for executive functioning and fluid intelligence in nondemented middle-aged and older adults.
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| 3. |
- de Frias, Cindy M, et al.
(author)
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Catechol O-methyltransferase Val158Met polymorphism is associated with cognitive performance in nondemented adults.
- 2005
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In: Journal of cognitive neuroscience. - Cambridge : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 17:7, s. 1018-25
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Journal article (peer-reviewed)abstract
- The catechol O-methyltransferase (COMT) gene is essential in the metabolic degradation of dopamine in the prefrontal cortex. In the present study, we examined the effect of a Val158Met polymorphism in the COMT gene on individual differences and changes in cognition (executive functions and visuospatial ability) in adulthood and old age. The participants were 292 nondemented men (initially aged 35-85 years) from a random sample of the population (i.e., the Betula study) tested at two occasions with a 5-year interval. Confirmatory factor analyses were used to test the underlying structure of three indicators of executive functions (verbal fluency, working memory, and Tower of Hanoi). Associations between COMT, age, executive functioning, and visuospatial (block design) tasks were examined using repeated-measures analyses of variance. Carriers of the Val allele (with higher enzyme activity) compared with carriers of the Met/Met genotype (with low enzyme activity) performed worse on executive functioning and visuospatial tasks. Individuals with the Val/Val genotype declined in executive functioning over the 5-year period, whereas carriers of the Met allele remained stable in performance. An Age x COMT interaction for visuospatial ability located the effect for middle-aged men only. This COMT polymorphism is a plausible candidate gene for executive functioning and fluid intelligence in nondemented middle-aged and older adults.
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| 4. |
- Edin, Fredrik, et al.
(author)
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Stronger synaptic connectivity as a mechanism behind development of working memory-related brain activity during childhood
- 2007
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 19:5, s. 750-760
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Journal article (peer-reviewed)abstract
- The cellular maturational processes behind cognitive development during childhood, including the development of working memory capacity, are still unknown. By using the most standard computational model of visuospatial working memory, we investigated the consequences of cellular maturational processes, including myelination, synaptic strengthening, and synaptic pruning, on working memory-related brain activity and performance. We implemented five structural developmental changes occurring as a result of the cellular maturational processes in the biophysically based computational network model. The developmental changes in memory activity predicted from the simulations of the model were then compared to brain activity measured with functional magnetic resonance imaging in children and adults. We found that networks with stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli, but not those with faster conduction, stronger connectivity within a region, or increased coding specificity, predict measured developmental increases in both working memory-related brain activity and in correlations of activity between regions. Stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli was thus the only developmental process that accounted for the observed changes in brain activity associated with development of working memory during childhood.
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| 5. |
- Eriksson, Johan, et al.
(author)
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Item-specific training reduces prefrontal cortical involvement in perceptual awareness
- 2008
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In: Journal of cognitive neuroscience. - Cambridge, Mass. : MIT Press with the Cognitive Neuroscience Institute. - 0898-929X .- 1530-8898. ; 20:10, s. 1777-1787
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Journal article (peer-reviewed)abstract
- Previous studies on the neural correlates of perceptual awareness implicate sensory-specific regions and higher cortical regions such as the prefrontal cortex (PFC) in this process. The specific role of PFC regions is, however, unknown. PFC activity could be bottom-up driven, integrating signals from sensory regions. Alternatively, PFC regions could serve more active top-down processes that help to define the content of consciousness. To compare these alternative views of PFC function, we used functional magnetic resonance imaging and measured brain activity specifically related to conscious perception of items that varied in ease of identification (by being presented 0, 12, or 60 times previously). A bottom-up account predicts that PFC activity would be largely insensitive to stimulus difficulty, whereas a top-down account predicts reduced PFC activity as identification becomes easier. The results supported the latter prediction by showing reduced activity for previously presented compared to novel items in the PFC and several other regions. This was further confirmed by a functional connectivity analysis showing that the interaction between frontal and visual sensory regions declined as a function of ease of identification. Given the attribution of top-down processing to PFC regions in combination with the marked decline in PFC activity for easy items, these findings challenge the prevailing notion that the PFC is necessary for consciousness.
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| 6. |
- Kitada, Ryo, et al.
(author)
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Functional specialization and convergence in the occipito-temporal cortex supporting haptic and visual identification of human faces and body parts : An fMRI study
- 2009
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 21:10, s. 2027-2045
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Journal article (peer-reviewed)abstract
- Humans can recognize common objects by touch extremely well whenever vision is unavailable. Despite its importance to a thorough understanding of human object recognition, the neuroscientific study of this topic has been relatively neglected. To date, the few published studies have addressed the haptic recognition of nonbiological objects. We now focus on haptic recognition of the human body, a particularly salient object category for touch. Neuroimaging studies demonstrate that regions of the occipito-temporal cortex are specialized for visual perception of faces (fusiform face area, FFA) and other body parts (extrastriate body area, EBA). Are the same category-sensitive regions activated when these components of the body are recognized haptically? Here, we use fMRI to compare brain organization for haptic and visual recognition of human body parts. Sixteen subjects identified exemplars of faces, hands, feet, and nonbiological control objects using vision and haptics separately. We identified two discrete regions within the fusiform gyrus (FFA and the haptic face region) that were each sensitive to both haptically and visually presented faces; however, these two regions differed significantly in their response patterns. Similarly, two regions within the lateral occipito-temporal area (EBA and the haptic body region) were each sensitive to body parts in both modalities, although the response patterns differed. Thus, although the fusiform gyrus and the lateral occipito-temporal cortex appear to exhibit modality-independent, category-sensitive activity, our results also indicate a degree of functional specialization related to sensory modality within these structures.
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| 7. |
- MacDonald, SWS, et al.
(author)
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Increased response-time variability is associated with reduced inferior parietal activation during episodic recognition in aging
- 2008
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 20:5, s. 779-786
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Journal article (peer-reviewed)abstract
- Intraindividual variability (IIV) in cognitive performance shares systematic associations with aging-related processes, brain injury, and neurodegenerative pathology. However, little research has examined the neural underpinnings of IIV, with no studies investigating brain correlates of IIV in relation to retrieval success. Using functional magnetic resonance imaging, we examined links between IIV, recognition memory performance, and blood oxygenation level dependent activations. Nineteen older adults (70–79 years) were presented with 80 words at encoding, with brain scans and response latencies obtained during subsequent recognition. An index of IIV, the intraindividual standard deviation (ISD), was computed across successful latency trials. Decreasing ISDs were systematically associated with better recognition, faster latencies, and increased activation in the inferior parietal cortex (BA 40). Demonstrated links between less behavioral variability and parietal activations are consistent with the known importance of the parietal cortex for retrieval success. In support of extant findings and theory from neuroscience, neuropsychology, and cognitive aging, the present results suggest that behavioral IIV represents a proxy for neural integrity.
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| 8. |
- Menenti, L, et al.
(author)
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When elephants fly: differential sensitivity of right and left inferior frontal gyri to discourse and world knowledge
- 2009
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 21:12, s. 2358-2368
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Journal article (peer-reviewed)abstract
- Both local discourse and world knowledge are known to influence sentence processing. We investigated how these two sources of information conspire in language comprehension. Two types of critical sentences, correct and world knowledge anomalies, were preceded by either a neutral or a local context. The latter made the world knowledge anomalies more acceptable or plausible. We predicted that the effect of world knowledge anomalies would be weaker for the local context. World knowledge effects have previously been observed in the left inferior frontal region (Brodmann's area 45/47). In the current study, an effect of world knowledge was present in this region in the neutral context. We also observed an effect in the right inferior frontal gyrus, which was more sensitive to the discourse manipulation than the left inferior frontal gyrus. In addition, the left angular gyrus reacted strongly to the degree of discourse coherence between the context and critical sentence. Overall, both world knowledge and the discourse context affect the process of meaning unification, but do so by recruiting partly different sets of brain areas.
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| 9. |
- Stenberg, Georg, et al.
(author)
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Familiarity or conceptual priming – event-related potentials in name recognition
- 2009
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In: Journal of Cognitive Neuroscience. - : MIT Press - Journals. - 1530-8898 .- 0898-929X. ; 21:3, s. 447-460
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Journal article (peer-reviewed)abstract
- Recent interest has been drawn to the separate components of recognition memory, as studied by event-related potentials (ERPs). In ERPs, recollection is usually accompanied by a late, parietal positive deflection. An earlier, frontal component has been suggested to be a counterpart, accompanying recognition by familiarity. However, this component, the FN400, has alternatively been suggested to reflect a form of implicit memory, conceptual priming. The present study examined the ERP components of recognition memory using an episodic memory task with a stimulus material consisting of names, half of which were famous. Along a different dimension, the names varied in how rare or common they were. These dimensions, frequency and fame, exerted powerful effects on memory accuracy, and dissociated the two recognition processes, such that frequency gave rise to familiarity and fame fostered recollection, when the receiver operating characteristics data were analyzed with Yonelinas' dual-process signal detection model. The ERPs corresponded fully to the behavioral data because frequency affected the frontal component exclusively, and fame affected the parietal component exclusively. Moreover, a separate behavioral experiment showed that conceptual priming was sensitive to fame, but not to frequency. Our data therefore indicate that the FN400 varies jointly with familiarity, but independently of conceptual priming.
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| 10. |
- Tesink, CMJY, et al.
(author)
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Unification of speaker and meaning in language comprehension: an FMRI study
- 2009
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 21:11, s. 2085-2099
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Journal article (peer-reviewed)abstract
- When interpreting a message, a listener takes into account several sources of linguistic and extralinguistic information. Here we focused on one particular form of extralinguistic information, certain speaker characteristics as conveyed by the voice. Using functional magnetic resonance imaging, we examined the neural structures involved in the unification of sentence meaning and voice-based inferences about the speaker's age, sex, or social background. We found enhanced activation in the inferior frontal gyrus bilaterally (BA 45/47) during listening to sentences whose meaning was incongruent with inferred speaker characteristics. Furthermore, our results showed an overlap in brain regions involved in unification of speaker-related information and those used for the unification of semantic and world knowledge information [inferior frontal gyrus bilaterally (BA 45/47) and left middle temporal gyrus (BA 21)]. These findings provide evidence for a shared neural unification system for linguistic and extralinguistic sources of information and extend the existing knowledge about the role of inferior frontal cortex as a crucial component for unification during language comprehension.
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