scholarly journals Tractography-Based Analysis of Morphological and Anatomical Characteristics of the Uncinate Fasciculus in Human Brains

2020 ◽  
Vol 10 (10) ◽  
pp. 709 ◽  
Author(s):  
Sara Kierońska ◽  
Paweł Sokal ◽  
Marta Dura ◽  
Magdalena Jabłońska ◽  
Marcin Rudaś ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Morphological Characteristics ◽  
Psychological State ◽  
Hemispheric Dominance ◽  
Uncinate Fasciculus ◽  
Volume Number ◽  
The Right

(1) Background: The uncinate fasciculus (UF) is a white matter bundle connecting the prefrontal cortex and temporal lobe. The functional role of the uncinate fasciculus is still uncertain. The role of the UF is attributed to the emotional empathy network. The present study aimed to more accurately the describe anatomical variability of the UF by focusing on the volume of fibers and testing for correlations with sex and age. (2) Material and Methods: Magnetic resonance imaging of adult patients with diffusion tensor imaging (DTI) was performed on 34 patients. The total number of fibers, volume of UF, and number of tracts were processed using DSI studio software. The DSI studio allows for mapping of different nerve pathways and visualizing of the obtained results using spatial graphics. (3) Results: The total number of UF tracts was significantly higher in the right hemisphere compared to the left hemisphere (right M ± SD = 52 ± 24; left: 39 ± 25, p < 0.05). A hook-shaped UF was the most common variant (91.7%). The UF volumes were larger in men (1410 ± 150.7 mm3) as compared to women (1325 ± 133.2 mm3) (p < 0.05). The mean fractional anisotropy (FA) values of the UF were significantly larger on the left side 0.597, while the right UF had an average of 0.346 (p < 0.05). Patients older than 50 years old had a significantly higher value of mean diffusivity (MD) (p = 0.034). In 73.5% of patients, a greater number of fibers terminated in the inferior part of the inferior frontal gyrus. (4) Conclusions: The morphological characteristics of the UF, unlike the shape, are associated with sex and are characterized by hemispheric dominance. These findings confirm the results of the previous studies. Future research should examine the potential correlation among the UF volume, number of fibers, and total brain volume in both sexes and patient psychological state.

Excitatory Deep Transcranial Magnetic Stimulation With H-Coil Over the Right Homologous Broca’s Region Improves Naming in Chronic Post-stroke Aphasia

2013 ◽  
Vol 28 (3) ◽  
pp. 291-298 ◽  
Author(s):  
Raffaella Chieffo ◽  
Federico Ferrari ◽  
Petronilla Battista ◽  
Elise Houdayer ◽  
Arturo Nuara ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Right Hemisphere ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Random Sequence ◽  
Inferior Frontal Gyrus ◽  
Naming Task ◽  
Broca’S Region ◽  
The Right

Background. The role of the right hemisphere in poststroke aphasia recovery is still controversial and the effects of repetitive transcranial magnetic stimulation (rTMS) over the right homologous Broca’s region have been seldom investigated. Objective. This study aimed to compare the effect of excitatory, inhibitory, and sham rTMS delivered with H-coil over the right inferior frontal gyrus in chronic aphasic patients. Methods. Five right-handed poststroke aphasic patients underwent a picture naming task before and immediately after each of 3 sessions of rTMS: excitatory (10 Hz), inhibitory (1 Hz), and sham rTMS, in random sequence and separated by at least 1 week. Results. Only the excitatory 10-Hz stimulation was associated with a significant improvement in naming performance ( P = .043) and was significantly more effective than 1-Hz rTMS ( P = .043). Conclusions. A single session of excitatory deep brain rTMS over the right inferior frontal gyrus with H-coil significantly improves naming in right-handed chronic poststroke aphasic patients. This result is in line with the hypothesis of a positive, rather than detrimental, role of the right hemisphere in chronic aphasia due to a left-hemispheric stroke.

scholarly journals The Role of the Right Hemisphere White Matter Tracts in Chronic Aphasic Patients After Damage of the Language Tracts in the Left Hemisphere

2021 ◽  
Vol 15 ◽  
Author(s):  
Evie Kourtidou ◽  
Dimitrios Kasselimis ◽  
Georgia Angelopoulou ◽  
Efstratios Karavasilis ◽  
Georgios Velonakis ◽  
...  
Keyword(s):  
White Matter ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Language Performance ◽  
White Matter Tracts ◽  
Post Stroke ◽  
Language Functions ◽  
The Right

The involvement of the right hemisphere (RH) in language, and especially after aphasia resulting from left hemisphere (LH) lesions, has been recently highlighted. The present study investigates white matter structure in the right hemisphere of 25 chronic post-stroke aphasic patients after LH lesions in comparison with 24 healthy controls, focusing on the four cortico-cortical tracts that link posterior parietal and temporal language-related areas with Broca’s region in the inferior frontal gyrus of the LH: the Superior Longitudinal Fasciculi II and III (SLF II and SLF III), the Arcuate Fasciculus (AF), and the Temporo-Frontal extreme capsule Fasciculus (TFexcF). Additionally, the relationship of these RH white matter tracts to language performance was examined. The patients with post-stroke aphasia in the chronic phase and the healthy control participants underwent diffusion tensor imaging (DTI) examination. The aphasic patients were assessed with standard aphasia tests. The results demonstrated increased axial diffusivity in the RH tracts of the aphasic patients. Patients were then divided according to the extent of the left hemisphere white matter loss. Correlations of language performance with radial diffusivity (RD) in the right hemisphere homologs of the tracts examined were demonstrated for the TFexcF, SLF III, and AF in the subgroup with limited damage to the LH language networks and only with the TFexcF in the subgroup with extensive damage. The results argue in favor of compensatory roles of the right hemisphere tracts in language functions when the LH networks are disrupted.

scholarly journals The Role of the Right Cerebral Hemisphere in Processing Novel Metaphoric Expressions: A Transcranial Magnetic Stimulation Study

2008 ◽  
Vol 20 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Gorana Pobric ◽  
Nira Mashal ◽  
Miriam Faust ◽  
Michal Lavidor
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Right Hemisphere ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Brain Activity ◽  
Inferior Frontal Gyrus ◽  
Judgment Task ◽  
Semantic Judgment ◽  
The Right

Previous research suggests that the right hemisphere (RH) may contribute uniquely to the processing of metaphoric language. However, causal relationships between local brain activity in the RH and metaphors comprehension were never established. In addition, most studies have focused on familiar metaphoric expressions which might be processed similarly to any conventional word combination. The present study was designed to overcome these two problems by employing repetitive transcranial magnetic stimulation (rTMS) to examine the role of the RH in processing novel metaphoric expressions taken from poetry. Right-handed participants were presented with four types of word pairs, literal, conventional metaphoric and novel metaphoric expressions, and unrelated word pairs, and were asked to perform a semantic judgment task. rTMS of the right posterior superior temporal sulcus disrupted processing of novel but not conventional metaphors, whereas rTMS over the left inferior frontal gyrus selectively impaired processing of literal word pairs and conventional but not novel metaphors (Experiment 1). In a further experiment, we showed that these effects were due to right-left asymmetries rather than posterior-anterior differences (Experiment 2). This is the first demonstration of TMS-induced impairment in processing novel metaphoric expressions, and as such, confirms the specialization of the RH in the activation of a broader range of related meanings than the left hemisphere, including novel, nonsalient meanings. The findings thus suggest that the RH may be critically involved in at least one important component of novel metaphor comprehension, the integration of the individual meanings of two seemingly unrelated concepts into a meaningful metaphoric expression.

scholarly journals The role of the uncinate fasciculus in the risk-architecture of bipolar disorders: A meta-analysis

2021 ◽  
Author(s):  
Ellie Xu ◽  
Lynn Nguyen ◽  
Rebecca Hu ◽  
Caitlin Stavish ◽  
Ellen Leibenluft ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Meta Analysis ◽  
Familial Risk ◽  
Region Of Interest ◽  
Bipolar Disorders ◽  
Uncinate Fasciculus ◽  
Increased Risk ◽  
The Right ◽  
Meta Analyses

Background: Bipolar disorder (BD) is a severe mental disorder, characterized by prominent mood swings and emotion regulation (ER) deficits. The uncinate fasciculus (UF), a white matter tract connecting the amygdala and the ventral prefrontal cortex, has been implicated in ER. Aberrancies in UF microstructure may be an endophenotype associated with increased risk for BD. However, findings in individuals with BD and at familial risk for BD (AR) have yielded inconsistent findings. This meta-analysis takes a region-of-interest approach to consolidate the available evidence and elucidate the role of the UF in the risk-architecture of BD. Methods: Using web-based search engines, we identified diffusion tensor imaging studies focusing on the left and right UF and conducted meta-analyses comparing fractional anisotropy (FA) and radial diffusivity (RD) between BD or AR to healthy volunteers (HV). Results: We included 32 studies (BD: n=1186, HV: n=2001; AR: n=289, HV-AR: n=314). Compared to HV, individuals with BD showed lower FA in the right (p<.0001) and left UF (p=.010), and higher RD in the right UF (p=.009). We found no significant differences between AR and HV. In the right but not the left UF, AR individuals showed higher FA than BD (p=.043). Conclusion: Comparable UF microstructure between AR and HV and higher FA in the right UF in AR compared to BD suggest that aberrancies in UF microstructure is not an endophenotype for BD. Longitudinal studies are needed to determine when UF abnormalities emerge in the context of BD.

Association fibers connecting the Broca center and the lateral superior frontal gyrus: a microsurgical and tractographic anatomy

2012 ◽  
Vol 116 (2) ◽  
pp. 323-330 ◽  
Author(s):  
Masashi Kinoshita ◽  
Harumichi Shinohara ◽  
Osamu Hori ◽  
Noriyuki Ozaki ◽  
Fumiaki Ueda ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Language Mapping ◽  
Cerebral Lesions ◽  
Superior Frontal Gyrus ◽  
Structural Connection ◽  
The Right ◽  
Association Fibers

Object Recently, intraoperative mapping has disclosed that, in addition to the classic language centers (that is, the Broca and Wernicke centers), other cortical regions may also play an important role in language organization. In the prefrontal cortex, although the lateral superior frontal gyrus (LSFG) could have language-related functions, there are no detailed reports that demonstrate the anatomical connection between the LSFG and other well-known language cortices, such as the Broca center. To show the existence of the structural connection, white matter association fibers between the inferior frontal gyrus (IFG) and the LSFG were examined using fiber dissection (FD) and diffusion tensor (DT) imaging–based tractography. Methods Eight cadaveric cerebral hemispheres were dissected to reveal the association fibers between the IFG and LSFG. The DT imaging–based tractography studies targeting the prefrontal cortex were obtained in 53 right-handed patients who had no organic cerebral lesions. Results The association fiber tract between Brodmann area 44/45 (the Broca center in the dominant hemisphere) and LSFG were detected in all specimens by FD. In the DT imaging–based tractography studies, the tract was identified in all patients bilaterally, except for the 4 in whom the tract was detected only in the left hemisphere. This tract was spread significantly wider in the left than in the right hemisphere, and left lateralization was evident in male patients. Conclusions Based on its character, this tract was named the Broca-LSFG pathway. These findings suggest a close relationship between this pathway and language organization. The structural anatomy of the Broca-LSFG pathway may explain speech disturbances induced by LSFG stimulation that are sometimes observed during intraoperative language mapping.

The role of the right inferior frontal gyrus following reversal of consistent stimulus-stop mappings

2013 ◽  
Author(s):  
Maisy Best ◽  
Tobias Stevens ◽  
Fraser Milton ◽  
Christopher D. Chambers ◽  
Ian P. McLaren ◽  
...  
Keyword(s):  
Inferior Frontal Gyrus ◽  
The Right

scholarly journals Structural and Functional Imaging in Glioma Management

Neurosurgery ◽  
2020 ◽  
Author(s):  
Bledi C Brahimaj ◽  
Ryan B Kochanski ◽  
John J Pearce ◽  
Melike Guryildirim ◽  
Carter S Gerard ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Imaging Modalities ◽  
Hemispheric Dominance ◽  
Tumor Control ◽  
Histopathological Diagnosis ◽  
Glioma Surgery ◽  
Multiple Modalities ◽  
Advantages And Disadvantages ◽  
Multiple Imaging

Abstract The goal of glioma surgery is maximal safe resection in order to provide optimal tumor control and survival benefit to the patient. There are multiple imaging modalities beyond traditional contrast-enhanced magnetic resonance imaging (MRI) that have been incorporated into the preoperative workup of patients presenting with gliomas. The aim of these imaging modalities is to identify cortical and subcortical areas of eloquence, and their relationship to the lesion. In this article, multiple modalities are described with an emphasis on the underlying technology, clinical utilization, advantages, and disadvantages of each. functional MRI and its role in identifying hemispheric dominance and areas of language and motor are discussed. The nuances of magnetoencephalography and transcranial magnetic stimulation in localization of eloquent cortex are examined, as well as the role of diffusion tensor imaging in defining normal white matter tracts in glioma surgery. Lastly, we highlight the role of stimulated Raman spectroscopy in intraoperative histopathological diagnosis of tissue to guide tumor resection. Tumors may shift the normal arrangement of functional anatomy in the brain; thus, utilization of multiple modalities may be helpful in operative planning and patient counseling for successful surgery.

scholarly journals Is Lateropulsion Really Related with a Specific Lesion of the Brain?

2021 ◽  
Vol 11 (3) ◽  
pp. 354
Author(s):  
Kyoung Lee ◽  
Sang Yoo ◽  
Eun Ji ◽  
Woo Hwang ◽  
Yeun Yoo ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Parietal Lobe ◽  
Inferior Frontal Gyrus ◽  
Brain Lesions ◽  
Vertical Posture ◽  
Lesion Volume ◽  
Precentral Gyrus ◽  
Stroke Patients ◽  
The Right ◽  
Right Hemisphere Stroke

Lateropulsion (pusher syndrome) is an important barrier to standing and gait after stroke. Although several studies have attempted to elucidate the relationship between brain lesions and lateropulsion, the effects of specific brain lesions on the development of lateropulsion remain unclear. Thus, the present study investigated the effects of stroke lesion location and size on lateropulsion in right hemisphere stroke patients. The present retrospective cross-sectional observational study assessed 50 right hemisphere stroke patients. Lateropulsion was diagnosed and evaluated using the Scale for Contraversive Pushing (SCP). Voxel-based lesion symptom mapping (VLSM) analysis with 3T-MRI was used to identify the culprit lesion for SCP. We also performed VLSM controlling for lesion volume as a nuisance covariate, in a multivariate model that also controlled for other factors contributing to pusher behavior. VLSM, combined with statistical non-parametric mapping (SnPM), identified the specific region with SCP. Lesion size was associated with lateropulsion. The precentral gyrus, postcentral gyrus, inferior frontal gyrus, insula and subgyral parietal lobe of the right hemisphere seemed to be associated with the lateropulsion; however, after adjusting for lesion volume as a nuisance covariate, no lesion areas were associated with the SCP scores. The size of the right hemisphere lesion was the only factor most strongly associated with lateropulsion in patients with stroke. These results may be useful for planning rehabilitation strategies of restoring vertical posture and understanding the pathophysiology of lateropulsion in stroke patients.

scholarly journals The Right Hemisphere Is Responsible for the Greatest Differences in Human Brain Response to High-Arousing Emotional versus Neutral Stimuli: A MEG Study

2021 ◽  
Vol 11 (8) ◽  
pp. 960
Author(s):  
Mina Kheirkhah ◽  
Philipp Baumbach ◽  
Lutz Leistritz ◽  
Otto W. Witte ◽  
Martin Walter ◽  
...  
Keyword(s):  
Human Brain ◽  
Right Hemisphere ◽  
Emotional Stimuli ◽  
Brain Response ◽  
Whole Brain ◽  
Brain Responses ◽  
Cortical Regions ◽  
The Right ◽  
Healthy Participants

Studies investigating human brain response to emotional stimuli—particularly high-arousing versus neutral stimuli—have obtained inconsistent results. The present study was the first to combine magnetoencephalography (MEG) with the bootstrapping method to examine the whole brain and identify the cortical regions involved in this differential response. Seventeen healthy participants (11 females, aged 19 to 33 years; mean age, 26.9 years) were presented with high-arousing emotional (pleasant and unpleasant) and neutral pictures, and their brain responses were measured using MEG. When random resampling bootstrapping was performed for each participant, the greatest differences between high-arousing emotional and neutral stimuli during M300 (270–320 ms) were found to occur in the right temporo-parietal region. This finding was observed in response to both pleasant and unpleasant stimuli. The results, which may be more robust than previous studies because of bootstrapping and examination of the whole brain, reinforce the essential role of the right hemisphere in emotion processing.

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