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Weiller 2002) . ... Strick 1991 , Fries et al. 1993 , Weiller et al. 1992 , Binkofski et al. 1995 , Nudo 1997 (Weiller et al. 1992 (Weiller et al. , 1993 Pantano et al. 1995 , Dettmers et al. 1997 , Cao et al. 1998 , Seitz ...doi:10.1007/978-3-642-12915-5_6 fatcat:7klk7rz3jjbwhns3ygb6pjpuy4
and Purpose-Silent ischemic brain lesions frequently occur in migraine with aura and are most often located in cerebellar border zones. This may imply an impairment of cerebellar blood flow autoregulation. This study investigated the characteristics of interictal cerebellar autoregulation in migraine with and without aura. Methods-Thirty-four patients (nϭ17, migraine without aura; nϭ17, migraine with aura) and 35 age-and sex-matched controls were studied. Triple simultaneous transcranialdoi:10.1161/strokeaha.111.644674 pmid:22343638 fatcat:zhwf4cr5gngcpgorwiqfl6w5ue
more »... monitoring of one posterior inferior cerebellar artery, right posterior cerebral artery, and left middle cerebral artery was performed. Autoregulation dynamics were assessed from spontaneous blood pressure fluctuations (correlation coefficient index Dx) and from respiratory-induced 0.1-Hz blood pressure oscillations (phase and gain). Results-Compared with controls, the autoregulatory index Dx was higher (indicating less autoregulation) in the posterior inferior cerebellar artery (Pϭ0.0062) and middle cerebral artery (Pϭ0.0078) in migraine with aura, but not in migraine without aura. Phase and gain did not significantly differ between migraine patients and controls. No significant associations of autoregulation with clinical factors were found, including frequency of migraine attacks and orthostatic intolerance. Conclusions-This first-time analysis of cerebellar autoregulation in migraine did not show a specific cerebellar dysautoregulation in the interictal period. More static autoregulatory properties (index Dx) are, however, impaired in persons with migraine with aura both in the cerebellar and anterior circulation. The cerebellar predilection of ischemic lesions in migraine with aura might be a combination of altered autoregulation and additional factors, such as the end artery cerebellar angioarchitecture. (Stroke. 2012;43:00-00.)
Journal of Neurology
Moreover, results indicate that brain areas involved in recovery (i) comprise right hemisphere areas homologue to damaged language areas and/or peri-lesional left-sided areas (Weiller et al., 1995; Musso ... patient groups with good language recovery: compensatory activation for damage of posterior language zones in recovered aphasia was shown to include bilateral IFG and homologous right temporal areas (Weiller ...doi:10.1093/brain/awv022 pmid:25688082 fatcat:e7h2uw65unff5asfa5c67i72te
Several functional imaging studies on the recovery of language in the chronic stage have shown (Weiller et al., 1992 (Weiller et al., , 1993 (Weiller et al., , 1998 Cappa et al., 1997; Heiss et al., 1997 ... altered comprehension in stroke patients would relate to a redistribution of activity to the unaffected areas of the neuronal network as the central mechanism of recovery from stroke (Mesulam, 1994; Weiller ...doi:10.1093/brain/122.9.1781 pmid:10468516 fatcat:umjkypjbbbholntum42qfadcc4
Weiller C,Ramsay SC,Wise RJS et al.Individual patterns of functional reorganization in the human cerebral cortex after capsular infarction. ... on phantom limb pain are mirrored in changes in cortical reorganization.J.Neurosci1997; 17:5503-8 48.Robertson ICH.Cognitive rehabilitation:attention and neglect.Trends Cogn Sci1999;3(10):385-393 49.Weiller ...doi:10.11253/ninchishinkeikagaku1999.3.69 fatcat:eppc62oygjaujen2jddcxhxvpm
This was the case for the complete corpus of naming items as well (joint independent component analysis in Abel, Huber, Weiller, & Specht, 2013; Abel, Weiller, Huber, Willmes, & Specht, 2014) . ... The importance of core LH language regions for compensation of language functions in aphasia as found in our patients was underlined by previous studies already, with a focus on inferior frontal (Weiller ...doi:10.1016/j.neuropsychologia.2014.03.010 pmid:24686092 fatcat:djtiwg23o5eoply55z5bye6osy
cal areas such as primary motor cortex (M1), supple-Department of Neurology mentary motor area (SMA), and basal ganglia (Grafton University of Hamburg Medical School et al., 1995; Hazeltine et al., 1997). Hamburg D-20246 In a recent memory study, it was demonstrated that Germany the motor system is also involved in learning probabilis-2 University of Cologne tic stimulus-response matching (Poldrack et al., 2001). Cologne D-50931 Two versions of a category learning task ("weather pre-Germanydoi:10.1016/s0896-6273(02)01105-4 pmid:12495634 fatcat:oioe3t5iujc5lc5uhghjeuoyaq
more »... ion") with probabilistic stimulus-outcome relations were directly compared to disentangle brain areas involved in declarative and nondeclarative memory. For a Summary given stimulus, subjects had to indicate the appropriate outcome by a button press. In one version, feedback The medial temporal lobe (MTL) has been associated (FB) was given after the button press, and the probabilwith declarative learning of flexible relational rules and the istic cue-outcome relations emphasized nondeclarabasal ganglia with implicit learning of stimulus-response tive memory processes. In the other version, subjects mappings. It remains an open question of whether MTL learned the stimuli and categories in a paired associates or basal ganglia are involved when learning flexible (PA) manner, where both stimuli were presented simultarelational contingencies without awareness. We studneously. In contrast to the FB task, the PA condition ied learning of an explicit stimulus-response associais thought to engage more declarative strategies. The tion with fMRI. Embedded in this explicit task was medial temporal lobe (MTL) was activated under the PA a hidden structure that was learnt implicitly. Implicit version of the task, whereas the basal ganglia were learning of the sequential regularities of the "hidden involved in the FB version. The authors concluded that rule" activated the ventral perirhinal cortex, within the MTL and basal ganglia acquire different types of infor-MTL, whereas learning the fixed stimulus-response mation during learning: the MTL acquires flexible, relaassociations activated the basal ganglia, indicating tional knowledge, whereas the basal ganglia acquire inthat the function of the MTL and the basal ganglia flexible, i.e., constant, stimulus-response associations. depends on the learned material and not necessarily An important question emerging from this study is on the participants' awareness. which area is involved in implicit learning in the absence of fixed stimulus-response associations but in the pres-
Language acquisition in humans relies on abilities like abstraction and use of syntactic rules, which are absent in other animals. The neural correlate of acquiring new linguistic competence was investigated with two functional magnetic resonance imaging (fMRI) studies. German native speakers learned a sample of 'real' grammatical rules of different languages (Italian or Japanese), which, although parametrically different, follow the universal principles of grammar (UG). Activity during thisdoi:10.1038/nn1077 pmid:12819784 fatcat:x7xi6mxfznbz7bbrvobdretd3e
more »... k was compared with that during a task that involved learning 'unreal' rules of language. 'Unreal' rules were obtained manipulating the original two languages; they used the same lexicon as Italian or Japanese, but were linguistically illegal, as they violated the principles of UG. Increase of activation over time in Broca's area was specific for 'real' language acquisition only, independent of the kind of language. Thus, in Broca's area, biological constraints and language experience interact to enable linguistic competence for a new language. Subordinate construction Pia wa Paul ga nashi o taberu to iu Pia sagt, dass Paul die Birne isst "Pia Paul pear eat that says" "Pia says that Paolo the pear eats" Unreal Japanese (artificial rules violating UG) Negative construction Paul wa nashi nai o taberu Paul pear eat no Interrogative construction Taberu o nashi wa Paul Pear eat Paul Past-tense construction Paul wa nashi o-ta taberu Paul pear-ta (suffix past) eat
Brain and Behavior
Previous picture-word interference (PWI) fMRI-paradigms revealed ambiguous mechanisms underlying facilitation and inhibition in healthy subjects. Lexical distractors revealed increased (enhancement) or decreased (suppression) activation in language and monitoring/control areas. Performing a secondary examination and data analysis, we aimed to illuminate the relation between behavioral and neural interference effects comparing target-related distractors (REL) with unrelated distractors (UNREL).doi:10.1002/brb3.31 pmid:22574280 pmcid:PMC3345356 fatcat:sicqvb6aivg4fi5wads332cwma
more »... e hypothesized that interference involves both (A) suppression due to priming and (B) enhancement due to simultaneous distractor and target processing. Comparisons to UNREL should remain distractor unspecific even at a low threshold. (C) Distractor types with common characteristics should reveal overlapping brain areas. In a 3T MRI scanner, participants were asked to name pictures while auditory words were presented (stimulus onset asynchrony [SOA] = -200 msec). Associatively and phonologically related distractors speeded responses (facilitation), while categorically related distractors slowed them down (inhibition) compared to UNREL. As a result, (A) reduced brain activations indeed resembled previously reported patterns of neural priming. Each target-related distractor yielded suppressions at least in areas associated with vision and conflict/competition monitoring (anterior cingulate cortex [ACC]), revealing least priming for inhibitors. (B) Enhancements concerned language-related but distractor-unspecific regions. (C) Some wider brain regions were commonly suppressed for combinations of distractor types. Overlapping areas associated with conceptual priming were found for facilitatory distractors (inferior frontal gyri), and areas related to phonetic/articulatory processing (precentral gyri and left parietal operculum/insula) for distractors sharing feature overlap. Each distractor with semantic relatedness revealed nonoverlapping suppressions in lexical-phonological areas (superior temporal regions). To conclude, interference combines suppression of areas well known from neural priming and enhancement of language-related areas caused by dual activation from target and distractor. Differences between interference and priming need to be taken into account. The present interference paradigm has the potential to reveal the functioning of word-processing stages, cognitive control, and responsiveness to priming at the same time.
doi:10.1002/ccr3.491 pmid:27014441 pmcid:PMC4771867 fatcat:s3ayywg6wzek7gjxqxadmc5qwe
Behavioral evidence suggests that spatial knowledge derived from ground-level navigation can consist of both route and survey knowledge. Neuroimaging and lesion studies aiming to identify the neural structures responsible for topographical learning in humans have yielded partially inconsistent results, probably due to the lack of an effective behavioral parameter allowing for a reliable distinction between different representations. Therefore, we employed a novel virtual reality environmentdoi:10.1016/j.cogbrainres.2004.06.013 pmid:15511655 fatcat:bighryxftvg77poq3zwr72z5ye
more »... provides accuracy and reaction time measures precisely indicating the emergence of route vs. survey knowledge. Functional magnetic resonance imaging (fMRI) was used to localize brain regions involved in the acquisition of pure route knowledge in the form of associations between consecutive landmark views and the direction of intermediate movements. Participants were scanned during repeated encoding of the complex environment from a first-person, ground-level perspective. Behavioral data revealed emerging route knowledge in 11 out of 14 subjects. Overall comparisons between encoding and control conditions identified activation in medial frontal gyrus, retrosplenial cortex and posterior inferior parietal cortex. Most importantly, only posterior inferior parietal regions showed increasing activation across sessions, thus paralleling behavioral measures of route expertise. Given the established role of the posterior parietal cortex in spatial processing, this area is thought to provide the pivotal spatial link between two landmarks encountered in immediate temporal succession. D
Knowledge on autoregulation of cerebellar blood flow in humans is scarce. This study investigated whether cerebellar autoregulation dynamics and CO 2 reactivity differ from those of the supratentorial circulation. In 56 healthy young adults, transcranial Doppler (TCD) monitoring of the posterior inferior cerebellar artery (PICA) and, simultaneously, of the contralateral middle cerebral artery (MCA) was performed. Autoregulation dynamics were assessed by the correlation coefficient methoddoi:10.1038/jcbfm.2008.48 pmid:18493256 fatcat:tkvrfwqskzccxpfdd745sfllqe
more »... s Dx and Mx) from spontaneous blood pressure fluctuations and by transfer function analysis (phase and gain) from respiratory-induced 0.1 Hz blood pressure oscillations. CO 2 reactivity was measured via inhalation of air mixed with 7% CO 2 . The autoregulatory indices Dx and Mx did not differ between the cerebellar (PICA) and cerebral (MCA) vasculature. Phase and gain, which describe faster aspects of autoregulation, showed slightly better values in the PICA compared with the MCA (higher phase, P = 0.005; lower gain, P = 0.007). Correlation between absolute autoregulation values in the PICA and the MCA was significant (P < 0.001). The TCD CO 2 reactivity was significantly lower in the PICA (P < 0.001), which could be influenced by an assumed PICA dilation under hypercapnia. In conclusion, dynamic autoregulation in the human cerebellum is well operating and has slightly faster regulatory properties than the anterior cerebral circulation.
Numerical cognition is a case of multi-modular and distributed cerebral processing. So far neither the anatomo-functional connections between the cortex areas involved nor their integration into established frameworks such as the differentiation between dorsal and ventral processing streams have been specified. The current study addressed this issue combining a reanalysis of previously published fMRI data with probabilistic fiber tracking data from an independent sample. We aimed atdoi:10.1371/journal.pone.0055455 pmid:23383194 pmcid:PMC3559478 fatcat:7or3wksbsjeajn4pvlmbvnjn4m
more »... ing neural correlates and connectivity for relatively easy and more difficult addition problems in healthy adults and their association with either rather verbally mediated fact retrieval or magnitude manipulations, respectively. The present data suggest that magnitude-and fact retrieval-related processing seem to be subserved by two largely separate networks, both of them comprising dorsal and ventral connections. Importantly, these networks not only differ in localization of activation but also in the connections between the cortical areas involved. However, it has to be noted that even though seemingly distinct anatomically, these networks operate as a functionally integrated circuit for mental calculation as revealed by a parametric analysis of brain activation.
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