| 1. |
- Elfgren, C I, et al.
(författare)
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Lateralized frontal blood flow increases during fluency tasks : influence of cognitive strategy
- 1998
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Ingår i: Neuropsychologia. - 0028-3932. ; 36:6, s. 12-505
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Tidskriftsartikel (refereegranskat)abstract
- Difficulties with verbal fluency tasks (VFIT) have been shown mainly to be associated with left frontal lobe pathology in lesion studies. The design fluency test (DFT) is a non-verbal analogue of word fluency tasks and has, in patients with right frontal lobe pathology, been coupled to an inability to perform well. Regional cerebral blood flow measurements (rCBF) were made in normals to elucidate the involvement of frontal and frontotemporal brain regions during the performance of VFT and DFT. In addition, the subjects' reports were used for obtaining information about the cognitive strategy used when solving the tasks. The results confirm previous CBF findings showing a mainly left-sided frontal activation during the VFT. During the DFT significant flow augmentations were seen in both frontal lobes compared to baseline. Furthermore, the use of different strategies was reflected in different patterns of brain activation. Our results support the proposal that the left frontal cortical area is engaged in the generation of internally driven responses. Furthermore, we argue that the cortical areas engaged during the execution of these tasks may reflect differences in cognitive strategy.
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| 2. |
- Petersson, K M, et al.
(författare)
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Dynamic changes in the functional anatomy of the human brain during recall of abstract designs related to practice
- 1999
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Ingår i: Neuropsychologia. - 0028-3932. ; 37:5, s. 87-567
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Tidskriftsartikel (refereegranskat)abstract
- In the present PET study we explore some functional aspects of the interaction between attentional/control processes and learning/memory processes. The network of brain regions supporting recall of abstract designs were studied in a less practiced and in a well practiced state. The results indicate that automaticity, i.e., a decreased dependence on attentional and working memory resources, develops as a consequence of practice. This corresponds to the practice related decreases of activity in the prefrontal, anterior cingulate, and posterior parietal regions. In addition, the activity of the medial temporal regions decreased as a function of practice. This indicates an inverse relation between the strength of encoding and the activation of the MTL during retrieval. Furthermore, the pattern of practice related increases in the auditory, posterior insular-opercular extending into perisylvian supramarginal region, and the right mid occipito-temporal region, may reflect a lower degree of inhibitory attentional modulation of task irrelevant processing and more fully developed representations of the abstract designs, respectively. We also suggest that free recall is dependent on bilateral prefrontal processing, in particular non-automatic free recall. The present results confirm previous functional neuroimaging studies of memory retrieval indicating that recall is subserved by a network of interacting brain regions. Furthermore, the results indicate that some components of the neural network subserving free recall may have a dynamic role and that there is a functional restructuring of the information processing networks during the learning process.
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| 8. |
- Prohovnik, Isak, et al.
(författare)
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Observations on the functional significance of regional cerebral blood flow in "resting" normal subjects.
- 1980
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Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 18:2, s. 203-17
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Tidskriftsartikel (refereegranskat)abstract
- Regional Cerebral Blood Flow (rCBF) of 16 cortical regions was measured bilaterally in 22 healthy adults, with 4–8 repeated measurements per individual. All measurements were done during “rest”, i.e. with minimal external stimulation, by the Xe-133 inhalation method. The data are presented to serve as normal controls for research and clinical work, but more importantly because of their significance for neuropsychological theory. Some rCBF variance is shown to be meaningfully related to handedness, habituation processes, biological rhythms and possibly to regional lateral dominance. Further data and discussion relate to the possible role of frontal lobe structures during non-task-oriented cognition. Finally, data are interpreted as showing that regional functional coupling across the midline, in this situation, is inversely related to the characteristic level-of-processing associated with each area.
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| 9. |
- Samuelsson, Stefan, 1964-
(författare)
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Converging evidence for the role of occipital regions in orthographic processing : A case of developmental surface dyslexia
- 2000
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Ingår i: Neuropsychologia. - 0028-3932 .- 1873-3514. ; 38:4, s. 351-362
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Tidskriftsartikel (refereegranskat)abstract
- Recently, there have been several reports focusing on the neural basis for word recognition. Two different views have emerged: one emphasizing the role of the left angular gyrus in recognizing printed words, and the second view suggesting that visual word processing activates the left extrastriate cortex. This paper describes the case of EBON, a 14-year-old girl with an extensive early (most likely congenital) brain lesion in the left occipital lobe. She demonstrates a clear pattern of developmental surface dyslexia in that she is more successful at reading and spelling regular words than irregular words and makes frequent regularisation errors. Thus, EBON is the first case reported with the potential to establish converging evidence for the role of extrastriate regions in the left hemisphere in the acquisition of orthographic representations. Copyright (C) 2000 Elsevier Science Ltd.
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| 10. |
- Ackerley, Rochelle, 1980, et al.
(författare)
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The role of tactile afference in shaping motor behaviour and implications for prosthetic innovation
- 2015
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Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932. ; 79:B, s. 192-205
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Tidskriftsartikel (refereegranskat)abstract
- The present review focusses on how tactile somatosensory afference is encoded and processed, and how this information is interpreted and acted upon in terms of motor control. We relate the fundamental workings of the sensorimotor system to the rehabilitation of amputees using modern prosthetic interventions. Our sense of touch is central to our everyday lives, from allowing us to manipulate objects accurately to giving us a sense of self-embodiment. There are a variety of specialised cutaneous mechanoreceptive afferents, which differ in terms of type and density according to the skin site. In humans, there is a dense innervation of our hands, which is reflected in their vast over-representation in somatosensory and motor cortical areas. We review the accumulated evidence from animal and human studies about the precise interplay between the somatosensory and motor systems, which is highly integrated in many brain areas and often not separable. The glabrous hand skin provides exquisite, discriminative detail about touch, which is useful for refining movements. When these signals are disrupted, such as through injury or amputation, the consequences are considerable. The development of sensory feedback in prosthetics offers a promising avenue for the full integration of a missing body part. Real-time touch feedback from motor intentions aids in grip control and the ability to distinguish different surfaces, even introducing the possibility of pleasure in artificial touch. Thus, our knowledge from fundamental research into sensorimotor interactions should be used to develop more realistic and integrative prostheses. (C) 2015 Elsevier Ltd. All rights reserved.
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