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| | 1. |
2010 Jul 22 |
Prominence vs. aboutness in sequencing: A functional distinction within the left inferior frontal gyrus.
Bornkessel-Schlesewsky I, Grewe T, Schlesewsky M
Brain Lang. 2010 Jul 22; [Epub ahead of print]
Abstract
Prior research on the neural bases of syntactic comprehension suggests that activation in the left inferior frontal gyrus (lIFG) correlates with the processing of word order variations. However, there are inconsistencies with respect to the specific subregion within the IFG that is implicated by these findings: the pars opercularis or the pars triangularis. Here, we examined the hypothesis that the dissociation between pars opercularis and pars triangularis activation may reflect functional differences between clause-medial and clause-initial word order permutations, respectively. To this end, we directly compared clause-medial and clause-initial object-before-subject orders in German in a within-participants, event-related fMRI design. Our results showed increased activation for object-initial sentences in a bilateral network of frontal, temporal and subcortical regions. Within the lIFG, posterior and inferior subregions showed only a main effect of word order, whereas more anterior and superior subregions showed effects of word order and sentence type, with higher activation for sentences with an argument in the clause-initial position. These findings are interpreted as evidence for a functional gradation of sequence processing within the left IFG: posterior subportions correlate with argument prominence-based (local) aspects of sequencing, while anterior subportions correlate with aboutness-based aspects of sequencing, which are crucial in linking the current sentence to the wider discourse. This proposal appears compatible with more general hypotheses about information processing gradients in prefrontal cortex (Koechlin & Summerfield, 2007).
[Pubmed: 20655580]
| | 2. |
2011 May 19 |
Parasites of cetaceans stranded on the Pacific coast of Costa Rica.
Oliveira JB, Morales JA, González-Barrientos RC, Hernández-Gamboa J, Hernández-Mora G
Vet Parasitol. 2011 May 19; [Epub ahead of print]
Abstract
Information regarding parasitic fauna of cetaceans from Costa Rica is provided for the first time. A total of 25 stranded dolphins and whales were examined between 2001 and 2009, including striped dolphin (Stenella coeruleoalba) (n=19), pantropical spotted dolphin (S. attenuata) (n=2), spinner dolphin (S. longirostris) (n=1), bottlenose dolphin (Tursiops truncatus) (n=1), dwarf sperm whale (Kogia sima) (n=1) and Cuvier's beaked whale (Ziphius cavirostris) (n=1). Pathological findings associated with the parasites are also presented. In the most representative dolphin species, S. coeruleoalba, the prevalence of parasites was 89.5%; moreover, all examined specimens of S. attenuata, S. longirostris, T. truncatus and Z. cavirostris presented parasites. No parasites were recovered from K. sima. Fourteen helminth taxa were identified, including six species of cestodes (Strobilocephalus triangularis, Tetrabothrius forsteri, Trigonocotyle sp., Phyllobothrium delphini, Monorygma grimaldi, Tetraphyllidea gen. sp. plerocercoid), four digeneans (Nasitrema globicephalae, Brachycladium palliatum, B. pacificum and Oschmarinella albamarina) and four nematodes (Anisakis spp., Halocercus lagenorhynchi, Halocercus sp. and Crassicauda anthonyi). A commensal crustacean, Xenobalanus globicipitis, was also identified. All identified parasites representing new geographic records for the Pacific coast of Central America and new host records are presented. Parasitological information is valuable for conservation of cetaceans in Pacific coast of Costa Rica.
[Pubmed: 21665367]
| | 3. |
2011 Mar 24 |
Different structural correlates for verbal memory impairment in temporal lobe epilepsy with and without mesial temporal lobe sclerosis.
Mueller SG, Laxer KD, Scanlon C, Garcia P, McMullen WJ, Loring DW, Meador KJ, Weiner MW
Hum Brain Mapp. 2011 Mar 24; [Epub ahead of print]
Abstract
Objectives: Memory impairment is one of the most prominent cognitive deficits in temporal lobe epilepsy (TLE). The overall goal of this study was to explore the contribution of cortical and hippocampal (subfield) damage to impairment of auditory immediate recall (AIMrecall), auditory delayed recall (ADMrecall), and auditory delayed recognition (ADMrecog) of the Wechsler Memory Scale III (WMS-III) in TLE with (TLE-MTS) and without hippocampal sclerosis (TLE-no). It was hypothesized that volume loss in different subfields determines memory impairment in TLE-MTS and temporal neocortical thinning in TLE-no. Methods: T1 whole brain and T2-weighted hippocampal magnetic resonance imaging and WMS-III were acquired in 22 controls, 18 TLE-MTS, and 25 TLE-no. Hippocampal subfields were determined on the T2 image. Free surfer was used to obtain cortical thickness averages of temporal, frontal, and parietal cortical regions of interest (ROI). MANOVA and stepwise regression analysis were used to identify hippocampal subfields and cortical ROI significantly contributing to AIMrecall, ADMrecall, and ADMrecog. Results: In TLE-MTS, AIMrecall was associated with cornu ammonis 3 (CA3) and dentate (CA3&DG) and pars opercularis, ADMrecall with CA1 and pars triangularis, and ADMrecog with CA1. In TLE-no, AIMrecall was associated with CA3&DG and fusiform gyrus (FUSI), and ADMrecall and ADMrecog were associated with FUSI. Conclusion: The study provided the evidence for different structural correlates of the verbal memory impairment in TLE-MTS and TLE-no. In TLE-MTS, the memory impairment was mainly associated by subfield-specific hippocampal and inferior frontal cortical damage. In TLE-no, the impairment was associated by mesial-temporal cortical and to a lesser degree hippocampal damage. Hum Brain Mapp, 2011. © 2011 Wiley-Liss, Inc.
[Pubmed: 21438080]
| | 4. |
2011 Aug 22 |
TMS suppression of right pars triangularis, but not pars opercularis, improves naming in aphasia.
Naeser MA, Martin PI, Theoret H, Kobayashi M, Fregni F, Nicholas M, Tormos JM, Steven MS, Baker EH, Pascual-Leone A
Brain Lang. 2011 Aug 22; [Epub ahead of print]
Abstract
This study sought to discover if an optimum 1 cm(2) area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions.
[Pubmed: 21864891]
| | 5. |
2011 Jun 29 |
Abnormal functional lateralization and activity of language brain areas in typical specific language impairment (developmental dysphasia).
de Guibert C, Maumet C, Jannin P, Ferré JC, Tréguier C, Barillot C, Le Rumeur E, Allaire C, Biraben A
Brain. 2011 Jun 29; [Epub ahead of print]
Abstract
Atypical functional lateralization and specialization for language have been proposed to account for developmental language disorders, yet results from functional neuroimaging studies are sparse and inconsistent. This functional magnetic resonance imaging study compared children with a specific subtype of specific language impairment affecting structural language (n = 21), to a matched group of typically developing children using a panel of four language tasks neither requiring reading nor metalinguistic skills, including two auditory lexico-semantic tasks (category fluency and responsive naming) and two visual phonological tasks based on picture naming. Data processing involved normalizing the data with respect to a matched pairs paediatric template, groups and between-groups analysis, and laterality indices assessment within regions of interest using single and combined task analysis. Children with specific language impairment exhibited a significant lack of left lateralization in all core language regions (inferior frontal gyrus-opercularis, inferior frontal gyrus-triangularis, supramarginal gyrus and superior temporal gyrus), across single or combined task analysis, but no difference of lateralization for the rest of the brain. Between-group comparisons revealed a left hypoactivation of Wernicke's area at the posterior superior temporal/supramarginal junction during the responsive naming task, and a right hyperactivation encompassing the anterior insula with adjacent inferior frontal gyrus and the head of the caudate nucleus during the first phonological task. This study thus provides evidence that this subtype of specific language impairment is associated with atypical lateralization and functioning of core language areas.
[Pubmed: 21719430]
| | 6. |
2011 Jun 24 |
Where, When and Why Brain Activation Differs for Bilinguals and Monolinguals during Picture Naming and Reading Aloud.
Parker Jones O, Green DW, Grogan A, Pliatsikas C, Filippopolitis K, Ali N, Lee HL, Ramsden S, Gazarian K, Prejawa S, Seghier ML, Price CJ
Cereb Cortex. 2011 Jun 24; [Epub ahead of print]
Abstract
Using functional magnetic resonance imaging, we found that when bilinguals named pictures or read words aloud, in their native or nonnative language, activation was higher relative to monolinguals in 5 left hemisphere regions: dorsal precentral gyrus, pars triangularis, pars opercularis, superior temporal gyrus, and planum temporale. We further demonstrate that these areas are sensitive to increasing demands on speech production in monolinguals. This suggests that the advantage of being bilingual comes at the expense of increased work in brain areas that support monolingual word processing. By comparing the effect of bilingualism across a range of tasks, we argue that activation is higher in bilinguals compared with monolinguals because word retrieval is more demanding; articulation of each word is less rehearsed; and speech output needs careful monitoring to avoid errors when competition for word selection occurs between, as well as within, language.
[Pubmed: 21705392]
| | 7. |
2011 Jul 23 |
New Genera, Species, and Improved Phylogeny of Glissomonadida (Cercozoa).
Howe AT, Bass D, Chao EE, Cavalier-Smith T
Protist. 2011 Nov;162(5):710-722. Epub 2011 Jul 23.
Abstract
Glissomonadida is an important cercozoan order of predominantly biflagellate gliding bacterivores found largely in soil and freshwater. Their vast diversity is largely undescribed. We studied 23 mostly newly isolated strains by light microscopy and sequenced their 18S rDNA genes; nine represent new species. For two misidentified ATCC 'Heteromita triangularis' strains, we establish novel gliding genera and species: the sandonid Mollimonas lacrima, the only glissomonad forming anterior and posterior pseudopodia, and Dujardina stenomorpha, a strongly flattened member of the new family Dujardinidae. A new strain from Oxfordshire grassland soil is the first reliably identified isolate of the virtually uniflagellate, smooth-gliding glissomonad genus, AllantionSandon, 1924. Phylogenetic analysis and cytological features reveal Allantion to be a member of Allapsidae. Sandona limna and Bodomorpha prolixa from Lake Baikal and Sandona hexamutans from volcanic Costa Rican soil are described as new species. Fifteen glissomonad strains were from grassland beside Lake Baikal. We describe two as new species of Sandona (S. heptamutans and S. octamutans); the others included strains of Sandona and Allapsa species that have already been described; and three were new species of Sandona and Allapsa but these died before being described. We discuss the ecological and evolutionary significance of these new strains.
[Pubmed: 21783412]
| | 8. |
2011 Mar 09 |
Who was the agent? The neural correlates of reanalysis processes during sentence comprehension.
Hirotani M, Makuuchi M, Rüschemeyer SA, Friederici AD
Hum Brain Mapp. 2011 Nov;32(11):1775-87. Epub 2011 Mar 09.
Abstract
Sentence comprehension is a complex process. Besides identifying the meaning of each word and processing the syntactic structure of a sentence, it requires the computation of thematic information, that is, information about who did what to whom. The present fMRI study investigated the neural basis for thematic reanalysis (reanalysis of the thematic roles initially assigned to noun phrases in a sentence) and its interplay with syntactic reanalysis (reanalysis of the underlying syntactic structure originally constructed for a sentence). Thematic reanalysis recruited a network consisting of Broca's area, that is, the left pars triangularis (LPT), and the left posterior superior temporal gyrus, whereas only LPT showed greater sensitivity to syntactic reanalysis. These data provide direct evidence for a functional neuroanatomical basis for two linguistically motivated reanalysis processes during sentence comprehension. Hum Brain Mapp , 2011. © 2010 Wiley-Liss, Inc.
[Pubmed: 21391256]
| | 9. |
2011 Mar 31 |
Inhibition-related Activation in the Right Inferior Frontal Gyrus in the Absence of Inhibitory Cues.
Lenartowicz A, Verbruggen F, Logan GD, Poldrack RA
J Cogn Neurosci. 2011 Nov;23(11):3388-99. Epub 2011 Mar 31.
Abstract
The right inferior frontal gyrus (rIFG) has been hypothesized to mediate response inhibition. Typically response inhibition is signaled by an external stop cue, which provides a top-down signal to initiate the process. However, recent behavioral findings suggest that response inhibition can also be triggered automatically by bottom-up processes. In the present study, we evaluated whether rIFG activity would also be observed during automatic inhibition, in which no stop cue was presented and no motor inhibition was actually required. We measured rIFG activation in response to stimuli that were previously associated with stop signals but which required a response on the current trial (reversal trials). The results revealed an increase in rIFG (pars triangularis) activity, suggesting that it can be activated by associations between stimuli and stopping. Moreover, its role in inhibition tasks is not contingent on the presence of an external stop cue. We conclude that rIFG involvement in stopping is consistent with a role in reprogramming of action plans, which may comprise inhibition, and its activity can be triggered through automatic, bottom-up processing.
[Pubmed: 21452946]
| | 10. |
2011 Sep 28 |
Mirror Therapy in Lower Limb Amputees - A Look Beyond Primary Motor Cortex Reorganization.
Seidel S, Kasprian G, Furtner J, Schöpf V, Essmeister M, Sycha T, Auff E, Prayer D
Rofo. 2011 Nov;183(11):1051-1057. Epub 2011 Sep 28.
Abstract
PURPOSE: Phantom pain in upper limb amputees is associated with the extent of reorganization in the primary sensorimotor cortex. Mirror visual feedback therapy has been shown to improve phantom pain. We investigated the extent of cortical reorganization in lower limb amputees and changes in neural activity induced by mirror therapy. MATERIALS AND METHODS: Eight lower limb amputees underwent 12 sessions of MVFT and functional magnetic resonance imaging (fMRI) of the brain before the first and after the last MVFT session. FMRI sessions consisted of two runs in which subjects were instructed to perform repetitive movement of the healthy and phantom ankle. RESULTS: Before MVFT, the mean phantom pain intensity was 4.6 ± 3.1 on a visual analog scale and decreased to 1.8 ± 1.7 (p = 0.04). We did not observe a consistent pattern of cortical activation in primary sensorimotor areas during phantom limb movements. Following MVFT, increased activity was obtained in the right orbitofrontal cortex during phantom ankle movements. Comparison of cortical activity during movements of the phantom ankle and the intact ankle showed significantly higher activity in the left inferior frontal cortex (pars triangularis). CONCLUSION: These results question the known association between phantom pain and primary sensorimotor reorganization and propose reorganizational changes involving multiple cortical areas in lower limb amputees. Finally, reduction of phantom pain after mirror visual feedback therapy was associated with increased prefrontal cortical activity during phantom ankle movements.
[Pubmed: 21959885]
| | 11. |
2011 Oct 26 |
Cortical folding in Broca's area relates to obstetric complications in schizophrenia patients and healthy controls.
Haukvik UK, Schaer M, Nesvåg R, McNeil T, Hartberg CB, Jönsson EG, Eliez S, Agartz I
Psychol Med. 2011 Oct 26;:1-9. Epub 2011 Oct 26.
Abstract
BACKGROUND: The increased occurrence of obstetric complications (OCs) in patients with schizophrenia suggests that alterations in neurodevelopment may be of importance to the aetiology of the illness. Abnormal cortical folding may reflect subtle deviation from normal neurodevelopment during the foetal or neonatal period. In the present study, we hypothesized that OCs would be related to cortical folding abnormalities in schizophrenia patients corresponding to areas where patients with schizophrenia display altered cortical folding when compared with healthy controls.MethodIn total, 54 schizophrenia patients and 54 healthy control subjects underwent clinical examination and magnetic resonance image scanning on a 1.5 T scanner. Information on OCs was collected from original birth records. An automated algorithm was used to calculate a three-dimensional local gyrification index (lGI) at numerous points across the cortical mantle. RESULTS: In both schizophrenia patients and healthy controls, an increasing number of OCs was significantly related to lower lGI in the left pars triangularis (p<0.0005) in Broca's area. For five other anatomical cortical parcellations in the left hemisphere, a similar trend was demonstrated. No significant relationships between OCs and lGI were found in the right hemisphere and there were no significant case-control differences in lGI. CONCLUSIONS: The reduced cortical folding in the left pars triangularis, associated with OCs in both patients and control subjects suggests that the cortical effect of OCs is caused by factors shared by schizophrenia patients and healthy controls rather than factors related to schizophrenia alone.
[Pubmed: 22029970]
| | 12. |
2011 Jan 19 |
Respiration-related control of abdominal motoneurons.
Iizuka M
Respir Physiol Neurobiol. 2011 Oct 15;179(1):80-8. Epub 2011 Jan 19.
Abstract
The abdominal muscles form part of the expiratory pump in cooperation with the other expiratory muscles, primarily the internal intercostal and triangularis sterni muscles. The discharge of abdominal muscles is divided into four main patterns: augmenting, plateau, spindle and decrementing. The patterns tend to be species-specific and dependent on the state of the central nervous system. Recent studies suggest that the abdominal muscles are more active than classically thought, even under resting conditions. Expiratory bulbospinal neurons (EBSN) in the caudal ventral respiratory group are the final output pathway to abdominal motoneurons in the spinal cord. Electrophysiological and anatomical studies indicated the excitatory monosynaptic inputs from EBSN to the abdominal motoneurons, although inputs from the propriospinal neurons seemed to be necessary to produce useful motor outputs. Respiration-related sensory modulation of expiratory neurons by vagal afferents that monitor the rate of change of lung volume and the end-expiratory lung volume (EELV) play a crucial role in modulating the drive to the abdominal musculature. Studies using in vitro and in situ preparations of neonatal and juvenile rats show bi-phasic abdominal activity, characterized by bursting at the end of expiration, a silent period during the inspiratory period, and another burst that occurs abruptly after inspiratory termination. Since the abdominal muscles rarely show these post-inspiratory bursts in the adult rat, the organization of the expiratory output pathway must undergo significant development alterations.
[Pubmed: 21255690]
| | 13. |
2011 Jun 30 |
The right hemisphere is not unitary in its role in aphasia recovery.
Turkeltaub PE, Coslett HB, Thomas AL, Faseyitan O, Benson J, Norise C, Hamilton RH
Cortex. 2011 Jun 30; [Epub ahead of print]
Abstract
Neurologists and aphasiologists have debated for over a century whether right hemisphere recruitment facilitates or impedes recovery from aphasia. Here we present a well-characterized patient with sequential left and right hemisphere strokes whose case substantially informs this debate. A 72-year-old woman with chronic nonfluent aphasia was enrolled in a trial of transcranial magnetic stimulation (TMS). She underwent 10 daily sessions of inhibitory TMS to the right pars triangularis. Brain activity was measured during picture naming using functional magnetic resonance imaging (fMRI) prior to TMS exposure and before and after TMS on the first day of treatment. Language and cognition were tested behaviorally three times prior to treatment, and at 2 and 6 months afterward. Inhibitory TMS to the right pars triangularis induced immediate improvement in naming, which was sustained 2 months later. fMRI confirmed a local reduction in activity at the TMS target, without expected increased activity in corresponding left hemisphere areas. Three months after TMS, the patient suffered a right hemisphere ischemic stroke, resulting in worsening of aphasia without other clinical deficits. Behavioral testing 3 months later confirmed that language function was impacted more than other cognitive domains. The paradoxical effects of inhibitory TMS and the stroke to the right hemisphere demonstrate that even within a single patient, involvement of some right hemisphere areas may support recovery, while others interfere. The behavioral evidence confirms that compensatory reorganization occurred within the right hemisphere after the original stroke. No support is found for interhemispheric inhibition, the theoretical framework on which most therapeutic brain stimulation protocols for aphasia are based.
[Pubmed: 21794852]
| | 14. |
2011 May 12 |
Self-face recognition in social context.
Sugiura M, Sassa Y, Jeong H, Wakusawa K, Horie K, Sato S, Kawashima R
Hum Brain Mapp. 2011 May 12; [Epub ahead of print]
Abstract
The concept of "social self" is often described as a representation of the self-reflected in the eyes or minds of others. Although the appearance of one's own face has substantial social significance for humans, neuroimaging studies have failed to link self-face recognition and the likely neural substrate of the social self, the medial prefrontal cortex (MPFC). We assumed that the social self is recruited during self-face recognition under a rich social context where multiple other faces are available for comparison of social values. Using functional magnetic resonance imaging (fMRI), we examined the modulation of neural responses to the faces of the self and of a close friend in a social context. We identified an enhanced response in the ventral MPFC and right occipitoparietal sulcus in the social context specifically for the self-face. Neural response in the right lateral parietal and inferior temporal cortices, previously claimed as self-face-specific, was unaffected for the self-face but unexpectedly enhanced for the friend's face in the social context. Self-face-specific activation in the pars triangularis of the inferior frontal gyrus, and self-face-specific reduction of activation in the left middle temporal gyrus and the right supramarginal gyrus, replicating a previous finding, were not subject to such modulation. Our results thus demonstrated the recruitment of a social self during self-face recognition in the social context. At least three brain networks for self-face-specific activation may be dissociated by different patterns of response-modulation in the social context, suggesting multiple dynamic self-other representations in the human brain. Hum Brain Mapp, 2011. © 2011 Wiley-Liss, Inc.
[Pubmed: 21567659]
| | 15. |
2011 Dec 21 |
Colateralization of Broca's area and the visual word form area in left-handers: fMRI evidence.
Van der Haegen L, Cai Q, Brysbaert M
Brain Lang. 2011 Dec 21; [Epub ahead of print]
Abstract
Language production has been found to be lateralized in the left hemisphere (LH) for 95% of right-handed people and about 75% of left-handers. The prevalence of atypical right hemispheric (RH) or bilateral lateralization for reading and colateralization of production with word reading laterality has never been tested in a large sample. In this study, we scanned 57 left-handers who had previously been identified as being clearly left (N=30), bilateral (N=7) or clearly right (N=20) dominant for speech on the basis of fMRI activity in the inferior frontal gyrus (pars opercularis/pars triangularis) during a silent word generation task. They were asked to perform a lexical decision task, in which words were contrasted against checkerboards, to test the lateralization of reading in the ventral occipitotemporal region. Lateralization indices for both tasks correlated significantly (r=0.59). The majority of subjects showed most activity during lexical decision in the hemisphere that was identified as their word production dominant hemisphere. However, more than half of the sample (N=31) had bilateral activity for the lexical decision task without a clear dominant role for either the LH or RH, and three showed a crossed frontotemporal lateralization pattern. These findings have consequences for neurobiological models relating phonological and orthographic processes, and for lateralization measurements for clinical purposes.
[Pubmed: 22196742]
| | 16. |
2012 Jan 18 |
The effect of sex and handedness on white matter anisotropy: a diffusion-tensor magnetic resonance imaging study.
Powell JL, Parkes L, Kemp GJ, Sluming V, Barrick TR, García-Fiñana M
Neuroscience. 2012 Jan 18; [Epub ahead of print]
Abstract
Diffusion-tensor magnetic resonance imaging provides a way of assessing the asymmetry of white matter (WM) connectivity, the degree of anisotropic diffusion within a given voxel being a marker of coherently bundled myelinated fibers. Voxel-based statistical analysis was performed on fractional anisotropy (FA) images of 42 right- and 40 left-handers, to assess differences in underlying WM anisotropy and FA asymmetry across the whole brain. Right-handers show greater anisotropy than left-handers in the uncinate fasciculus (UF) within the limbic lobe, and WM underlying prefrontal cortex, medial and inferior frontal gyri. Significantly greater leftward FA asymmetry in cerebellum posterior lobe is seen in left- than right-handers, and males show significantly greater rightward (right-greater-than-left) FA asymmetry in regions of middle occipital lobe, medial temporal gyrus, and a region of the superior longitudinal fasciculus underlying the supramarginal gyrus. Leftward (left-greater-than-right) anisotropy is found in regions of the arcuate fasciculus (AF), UF, and WM underlying pars triangularis in both handedness groups, with right-handers alone showing additional leftward FA asymmetry along the length of the superior temporal gyrus. Overall results indicate that although both handedness groups show anisotropy in similar WM regions, greater anisotropy is observed in right-handers compared with left-handers. The largest differences in FA asymmetry are found between males and females, suggesting a greater effect of sex than handedness on FA asymmetry.
[Pubmed: 22274289]
| | 17. |
2012 Jan 23 |
Serotonin Transporter Polymorphism Modulates N-Back Task Performance and fMRI BOLD Signal Intensity in Healthy Women
Jonassen, Endestad, Neumeister, Foss Haug, Berg, Landrø
PLoS One 2012 Jan 23;7(1). published online before print
Abstract
Exploring intermediate phenotypes within the human brain's functional and structural circuitry is a promising approach to explain the relative contributions of genetics, complex behaviors and neural mechanisms in the development of major depressive disorder (MDD). The polymorphic region 5-HTTLPR in the serotonin transporter gene (SLC6A4) has been shown to modulate MDD risk, but the neural underpinnings are incompletely understood.
[Pubmed: 22291990]
| | 18. |
2012 Mar 19 |
Differential roles of right temporal cortex and Broca's area in pitch processing: Evidence from music and Mandarin.
Nan Y, Friederici AD
Hum Brain Mapp. 2012 Mar 19; [Epub ahead of print]
Abstract
Superior temporal and inferior frontal cortices are involved in the processing of pitch information in the domain of language and music. Here, we used fMRI to test the particular roles of these brain regions in the neural implementation of pitch in music and in tone language (Mandarin) with a group of Mandarin speaking musicians whose pertaining experiences in pitch are similar across domains. Our findings demonstrate that the neural network for pitch processing includes the pars triangularis of Broca's area and the right superior temporal gyrus (STG) across domains. Within this network, pitch sensitive activation in Broca's area is tightly linked to the behavioral performance of pitch congruity judgment, thereby reflecting controlled processes. Activation in the right STG is independent of performance and more sensitive to pitch congruity in music than in tone language, suggesting a domain-specific modulation of the perceptual processes. These observations provide a first glimpse at the cortical pitch processing network shared across domains. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc.
[Pubmed: 22431306]
| | 19. |
2012 Mar 16 |
Functional parcellation of the inferior frontal and midcingulate cortices in a flanker-stop-change paradigm.
Enriquez-Geppert S, Eichele T, Specht K, Kugel H, Pantev C, Huster RJ
Hum Brain Mapp. 2012 Mar 16; [Epub ahead of print]
Abstract
Conflict monitoring and motor inhibition are engaged in the performance of complex tasks. The midcingulate cortex (MCC) has been suggested to detect conflicts, whereas the right inferior frontal cortex (IFC) seems to be of relevance for the inhibition process. The current experiment investigates the neural underpinnings of their interplay via a modified flanker paradigm. Conflict was manipulated by the congruency of flanking stimuli relative to a target (congruent vs. incongruent) and motor inhibition by a within-trial response change of the initiated response (keep response vs. stop-change). We used event-related functional magnetic resonance imaging, decomposition with high model order ICA, and single trial analysis to derive a functional parcellation of the whole-brain data. Results demonstrate the segmentation of the MCC into anterior and posterior subregions, and of the IFC into the pars opercularis, pars triangularis, and pars orbitalis. The pars opercularis and pars triangularis of the right IFC constituted the foundation of inhibition-related networks. With high conflict on incongruent trials, activity in the posterior MCC network, as well as in one right IFC network was observed. Stop-change trials modulated both the MCC as well as networks covering extended parts of the IFC. Whereas conflict processing and inhibition most often are studied separately, this study provides a synopsis of functionally coupled brain regions acting in concert to enable an optimal performance in situations involving interference and inhibition. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc.
[Pubmed: 22422710]
| | 20. |
2012 Mar 15 |
Localized gray matter volume reductions in the pars triangularis of the inferior frontal gyrus in individuals at clinical high-risk for psychosis and first episode for schizophrenia.
Iwashiro N, Suga M, Takano Y, Inoue H, Natsubori T, Satomura Y, Koike S, Yahata N, Murakami M, Katsura M, Gonoi W, Sasaki H, Takao H, Abe O, Kasai K, Yamasue H
Schizophr Res. 2012 Mar 15; [Epub ahead of print]
Abstract
Recent studies have suggested an important role for Broca's region and its right hemisphere counterpart in the pathophysiology of schizophrenia, owing to its roles in language and interpersonal information processing. Broca's region consists of the pars opercularis (PO) and the pars triangularis (PT). Neuroimaging studies have suggested that they have differential functional roles in healthy individuals and contribute differentially to the pathogenesis of schizophrenic symptoms. However, volume changes in these regions in subjects with ultra-high risk for psychosis (UHR) or first-episode schizophrenia (FES) have not been clarified. In the present 3Tesla magnetic resonance imaging study, we separately measured the gray matter volumes of the PO and PT using a reliable manual-tracing volumetry in 80 participants (20 with UHR, 20 with FES, and 40 matched controls). The controls constituted two groups: the first group was matched for age, sex, parental socioeconomic background, and intelligence quotient to UHR (n=20); the second was matched for those to FES (n=20). Compared with matched controls, the volume of the bilateral PT, but not that of the PO, was significantly reduced in the subjects with UHR and FES. The reduced right PT volume, which showed the largest effect size among regions-of-interest in the both UHR and FES groups, correlated with the severity of the positive symptoms also in the both groups. These results suggest that localized gray matter volume reductions of the bilateral PT represent a vulnerability to schizophrenia in contrast to the PO volume, which was previously found to be reduced in patients with chronic schizophrenia. The right PT might preferentially contribute to the pathogenesis of psychotic symptoms.
[Pubmed: 22425035]
| | 21. |
2011 Nov 02 |
Gesture in the developing brain.
Dick AS, Goldin-Meadow S, Solodkin A, Small SL
Dev Sci. 2012 Mar;15(2):165-80. Epub 2011 Nov 02.
Abstract
Speakers convey meaning not only through words, but also through gestures. Although children are exposed to co-speech gestures from birth, we do not know how the developing brain comes to connect meaning conveyed in gesture with speech. We used functional magnetic resonance imaging (fMRI) to address this question and scanned 8- to 11-year-old children and adults listening to stories accompanied by hand movements, either meaningful co-speech gestures or meaningless self-adaptors. When listening to stories accompanied by both types of hand movement, both children and adults recruited inferior frontal, inferior parietal, and posterior temporal brain regions known to be involved in processing language not accompanied by hand movements. There were, however, age-related differences in activity in posterior superior temporal sulcus (STSp), inferior frontal gyrus, pars triangularis (IFGTr), and posterior middle temporal gyrus (MTGp) regions previously implicated in processing gesture. Both children and adults showed sensitivity to the meaning of hand movements in IFGTr and MTGp, but in different ways. Finally, we found that hand movement meaning modulates interactions between STSp and other posterior temporal and inferior parietal regions for adults, but not for children. These results shed light on the developing neural substrate for understanding meaning contributed by co-speech gesture.
[Pubmed: 22356173]
| | 22. |
2012 Aug 11 |
Alterations in brain structures underlying language function in young adults at high familial risk for schizophrenia.
Francis AN, Seidman LJ, Jabbar GA, Mesholam-Gately R, Thermenos HW, Juelich R, Proal AC, Shenton M, Kubicki M, Mathew I, Keshavan M, Delisi LE
Schizophr. Res. 2012 Aug 11; [Epub ahead of print]
Abstract
INTRODUCTION: Neuroanatomical and cognitive alterations typical of schizophrenia (SZ) patients are observed to a lesser extent in their adolescent and adult first-degree relatives, likely reflecting neurodevelopmental abnormalities associated with genetic risk for the illness. The anatomical pathways for language are hypothesized to be abnormal and to underlie the positive symptoms of schizophrenia. Examining non-psychotic relatives at high familial risk (FHR) for schizophrenia may clarify if these deficits represent trait markers associated with genetic vulnerability, rather than specific markers resulting from the pathological process underlying schizophrenia. METHODS: T1 MRI scans from a 3T Siemens scanner of young adult FHR subjects (N=46) and controls with no family history of illness (i.e. at low genetic risk LRC; N=31) were processed using FreeSurfer 5.0. We explored volumetric and lateralization alterations in regions associated with language processing. An extensive neuropsychological battery of language measures was administered. RESULTS: No significant differences were observed between groups on any language measures. Controlling intracranial volume, significantly smaller left pars triangularis (PT) (p<0.01) and right pars orbitalis (PO) (p<0.01) volumes and reversal of the L>R pars orbitalis (p<0.001) lateralization were observed in FHR subjects. In addition, the L pars triangularis and R pars orbitalis correlated with performance on tests of linguistic function in the FHR group. CONCLUSIONS: Reduced volume and reversed structural asymmetry in language-related regions hypothesized to be altered in SZ are also found in first degree relatives at FHR, despite normal language performance. To clarify if these findings are endophenotypes for Sz, future studied would need to be performed of ill and well family members no longer within the age range of risk for illness to show these deficits segregate with schizophrenia within families. Moreover, measures of complex language need to be studied to determine if FHR individuals manifest impairments in some aspects of language function.
[Pubmed: 22892286]
| | 23. |
2012 Aug 9 |
Functional Connection Between Posterior Superior Temporal Gyrus and Ventrolateral Prefrontal Cortex in Human.
Garell PC, Bakken H, Greenlee JD, Volkov I, Reale RA, Oya H, Kawasaki H, Howard MA, Brugge JF
Cereb. Cortex. 2012 Aug 9; [Epub ahead of print]
Abstract
The connection between auditory fields of the temporal lobe and prefrontal cortex has been well characterized in nonhuman primates. Little is known of temporofrontal connectivity in humans, however, due largely to the fact that invasive experimental approaches used so successfully to trace anatomical pathways in laboratory animals cannot be used in humans. Instead, we used a functional tract-tracing method in 12 neurosurgical patients with multicontact electrode arrays chronically implanted over the left (n = 7) or right (n = 5) perisylvian temporal auditory cortex (area PLST) and the ventrolateral prefrontal cortex (VLPFC) of the inferior frontal gyrus (IFG) for diagnosis and treatment of medically intractable epilepsy. Area PLST was identified by the distribution of average auditory-evoked potentials obtained in response to simple and complex sounds. The same sounds evoked little if there is any activity in VLPFC. A single bipolar electrical pulse (0.2 ms, charge-balanced) applied between contacts within physiologically identified PLST resulted in polyphasic evoked potentials clustered in VLPFC, with greatest activation being in pars triangularis of the IFG. The average peak latency of the earliest negative deflection of the evoked potential on VLPFC was 13.48 ms (range: 9.0-18.5 ms), providing evidence for a rapidly conducting pathway between area PLST and VLPFC.
[Pubmed: 22879355]
| | 24. |
2012 Jul 31 |
The Effect of Aging on the Neural Correlates of Phonological Word Retrieval.
Geva S, Jones PS, Crinion JT, Price CJ, Baron JC, Warburton EA
J Cogn Neurosci. 2012 Jul 31; [Epub ahead of print]
Abstract
Age has a differential effect on cognition; with word retrieval being one of the cognitive domains most affected by aging. This study examined the functional and structural neural correlates of phonological word retrieval in younger and older adults using word and picture rhyme judgment tasks. Although the behavioral performance in the fMRI task was similar for the two age groups, the older adults had increased activation in the right pars triangularis across tasks and in the right pars orbitalis for the word task only. Increased activation together with preserved performance in the older participants would suggest that increased activation was related to compensatory processing. We validated this hypothesis by showing that right pars triangularis activation during correct rhyme judgments was highest in participants who made overall more errors, therefore being most error-prone. Our findings demonstrate that the effect of aging differ in adjacent but distinct right inferior frontal regions. The differential effect of age on word and picture tasks also provides new clues to the level of processing that is most affected by age in speech production tasks. Specifically, we suggest that right inferior frontal activation in older participants is needed to inhibit errors.
[Pubmed: 22849403]
| | 25. |
2012 May 10 |
Anatomic, clinical, and neuropsychological correlates of spelling errors in primary progressive aphasia.
Shim H, Hurley RS, Rogalski E, Mesulam MM
Neuropsychologia. 2012 Jul;50(8):1929-35. Epub 2012 May 10.
Abstract
This study evaluates spelling errors in the three subtypes of primary progressive aphasia (PPA): agrammatic (PPA-G), logopenic (PPA-L), and semantic (PPA-S). Forty-one PPA patients and 36 age-matched healthy controls were administered a test of spelling. The total number of errors and types of errors in spelling to dictation of regular words, exception words and nonwords, were recorded. Error types were classified based on phonetic plausibility. In the first analysis, scores were evaluated by clinical diagnosis. Errors in spelling exception words and phonetically plausible errors were seen in PPA-S. Conversely, PPA-G was associated with errors in nonword spelling and phonetically implausible errors. In the next analysis, spelling scores were correlated to other neuropsychological language test scores. Significant correlations were found between exception word spelling and measures of naming and single word comprehension. Nonword spelling correlated with tests of grammar and repetition. Global language measures did not correlate significantly with spelling scores, however. Cortical thickness analysis based on MRI showed that atrophy in several language regions of interest were correlated with spelling errors. Atrophy in the left supramarginal gyrus and inferior frontal gyrus (IFG) pars orbitalis correlated with errors in nonword spelling, while thinning in the left temporal pole and fusiform gyrus correlated with errors in exception word spelling. Additionally, phonetically implausible errors in regular word spelling correlated with thinning in the left IFG pars triangularis and pars opercularis. Together, these findings suggest two independent systems for spelling to dictation, one phonetic (phoneme to grapheme conversion), and one lexical (whole word retrieval).
[Pubmed: 22579708]
| | 26. |
2012 Jun 27 |
A temporal bottleneck in the language comprehension network.
Vagharchakian L, Dehaene-Lambertz G, Pallier C, Dehaene S
J. Neurosci. 2012 Jun 27;32(26):9089-102.
Abstract
Humans can understand spoken or written sentences presented at extremely fast rates of ∼400 wpm, far exceeding the normal speech rate (∼150 wpm). How does the brain cope with speeded language? And what processing bottlenecks eventually make language incomprehensible above a certain presentation rate? We used time-resolved fMRI to probe the brain responses to spoken and written sentences presented at five compression rates, ranging from intelligible (60-100% of the natural duration) to challenging (40%) and unintelligible (20%). The results show that cortical areas differ sharply in their activation speed and amplitude. In modality-specific sensory areas, activation varies linearly with stimulus duration. However, a large modality-independent left-hemispheric language network, including the inferior frontal gyrus (pars orbitalis and triangularis) and the superior temporal sulcus, shows a remarkably time-invariant response, followed by a sudden collapse for unintelligible stimuli. Finally, linear and nonlinear responses, reflecting a greater effort as compression increases, are seen at various prefrontal and parietal sites. We show that these profiles fit with a simple model according to which the higher stages of language processing operate at a fixed speed and thus impose a temporal bottleneck on sentence comprehension. At presentation rates faster than this internal processing speed, incoming words must be buffered, and intelligibility vanishes when buffer storage and retrieval operations are saturated. Based on their temporal and amplitude profiles, buffer regions can be identified with the left inferior frontal/anterior insula, precentral cortex, and mesial frontal cortex.
[Pubmed: 22745508]
| | 27. |
2012 Jun 12 |
Multivariate Activation and Connectivity Patterns Discriminate Speech Intelligibility in Wernicke's, Broca's, and Geschwind's Areas.
Abrams DA, Ryali S, Chen T, Balaban E, Levitin DJ, Menon V
Cereb Cortex. 2012 Jun 12; [Epub ahead of print]
Abstract
The brain network underlying speech comprehension is usually described as encompassing fronto-temporal-parietal regions while neuroimaging studies of speech intelligibility have focused on a more spatially restricted network dominated by the superior temporal cortex. Here we use functional magnetic resonance imaging with a novel whole-brain multivariate pattern analysis (MVPA) to more fully characterize neural responses and connectivity to intelligible speech. Consistent with previous univariate findings, intelligible speech elicited greater activity in bilateral superior temporal cortex relative to unintelligible speech. However, MVPA identified a more extensive network that discriminated between intelligible and unintelligible speech, including left-hemisphere middle temporal gyrus, angular gyrus, inferior temporal cortex, and inferior frontal gyrus pars triangularis. These fronto-temporal-parietal areas also showed greater functional connectivity during intelligible, compared with unintelligible, speech. Our results suggest that speech intelligibly is encoded by distinct fine-grained spatial representations and within-task connectivity, rather than differential engagement or disengagement of brain regions, and they provide a more complete view of the brain network serving speech comprehension. Our findings bridge a divide between neural models of speech comprehension and the neuroimaging literature on speech intelligibility, and suggest that speech intelligibility relies on differential multivariate response and connectivity patterns in Wernicke's, Broca's, and Geschwind's areas.
[Pubmed: 22693339]
| | 28. |
2012 Apr 23 |
Diminished whole-brain but enhanced peri-sylvian connectivity in absolute pitch musicians.
Jäncke L, Langer N, Hänggi J
J Cogn Neurosci. 2012 Jun;24(6):1447-61. Epub 2012 Apr 23.
Abstract
Several anatomical studies have identified specific anatomical features within the peri-sylvian brain system of absolute pitch (AP) musicians. In this study we used graph theoretical analysis of cortical thickness covariations (as indirect indicator of connectivity) to examine whether AP musicians differ from relative pitch musicians and nonmusicians in small-world network characteristics. We measured "local connectedness" (local clustering = γ), "global efficiency of information transfer" (path length = λ), "small-worldness" (σ = γ/λ), and "degree" centrality as measures of connectivity. Although all groups demonstrated typical small-world features, AP musicians showed significant small-world alterations. "Degree" as a measure of interconnectedness was globally significantly decreased in AP musicians. These differences let us suggest that AP musicians demonstrate diminished neural integration (less connections) among distant brain regions. In addition, AP musicians demonstrated significantly increased local connectivity in peri-sylvian language areas of which the planum temporale, planum polare, Heschl's gyrus, lateral aspect of the superior temporal gyrus, STS, pars triangularis, and pars opercularis were hub regions. All of these brain areas are known to be involved in higher-order auditory processing, working or semantic memory processes. Taken together, whereas AP musicians demonstrate decreased global interconnectedness, the local connectedness in peri-sylvian brain areas is significantly higher than for relative pitch musicians and nonmusicians.
[Pubmed: 22524277]
| | 29. |
2011 Aug 30 |
Anatomic relationship between the anterior sylvian point and the pars triangularis.
Ayberk G, Yagli OE, Comert A, Esmer AF, Canturk N, Tekdemir I, Dinc H
Clin Anat. 2012 May;25(4):429-36. Epub 2011 Aug 30.
Abstract
The aim of this study was to show morphological sulcal variations of the pars triangularis of the inferior frontal gyrus and to provide a clearer description of the anterior sylvian point. Thirty-six hemispheres of 18 adult cadavers were studied. The hemispheres were harvested by the classical autopsy method and fixed in 10% formalin solution for three weeks. In six hemispheres, the arteries and veins were filled with colored silicone. The proximal and distal segments of the sylvian fissure, the perpendicular distance of both the anterior sylvian point and inferior rolandic point to the insular cortex and the distances between the anterior ascending ramus and the precentral, central, and postcentral sulcus were measured. The anterior horizontal and ascending rami were exposed. The sulcus located on the pars triangularis was appraised. The relationship between the anterior sylvian point and the vascular structure around the sylvian fissure was examined. The rising of the anterior horizontal and ascending ramus from the sylvian fissure defines the shape of the pars triangularis. The pars triangularis has three shapes: V, U, and Y. In V- and Y-shaped pars triangularis both rami merge but in U-shaped pars triangularis the rami do not merge. The pars triangularis was Y-shaped in 30.76% (4/13) of the right hemispheres and in 50% (7/14) of the left hemispheres; U-shaped in 20.3% (3/13) of the right hemispheres and in 35.71% (5/14) of the left hemispheres; V-shaped in 40.61% (6/13) of the right hemispheres and in 14.29% (2/14) of the left hemispheres. Minimally invasive procedures use basic anatomic landmarks intracranially to reach the targeted area; therefore, exact and detailed knowledge of the anatomy of the sylvian fissure and pars triangularis is of great importance.
[Pubmed: 22488994]
| | 30. |
2012 Jul 13 |
The neural processing of second language comprehension modulated by the degree of proficiency: a listening connected speech FMRI study.
Hesling I, Dilharreguy B, Bordessoules M, Allard M
Open Neuroimag J. 2012;6:44-54. Epub 2012 Jul 13.
Abstract
While the neural network encompassing the processing of the mother tongue (L1) is well defined and has revealed the existence of a bilateral ventral pathway and a left dorsal pathway in which 3 loops have been defined, the question of the processing of a second language (L2) is still a matter of debate. Among variables accounting for the discrepancies in results, the degree of L2 proficiency appears to be one of the main factors. The present study aimed at assessing both pathways in L2, making it possible to determine the degree of mastery of the different speech components (prosody, phonology, semantics and syntax) that are intrinsically embedded within connected speech and that vary according to the degree of proficiency using high degrees of prosodic information. Two groups of high and moderate proficiency in L2 performed an fMRI comprehension task in L1 and L2. The modifications in brain activity observed within the dorsal and the ventral pathways according to L2 proficiency suggest that different processes of L2 are supported by differences in the integrated activity within distributed networks that included the left STSp, the left Spt and the left pars triangularis.
[Pubmed: 22927897]
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