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Sample records for large supratentorial cortical

  1. Small supratentorial, extraaxial primitive neuroectodermal tumor causing large intracerebral hematoma.

    PubMed

    Burkhardt, Jan-Karl; Kockro, Ralf A; Dohmen-Scheufler, Hildegard; Woernle, Christoph M; Bellut, David; Kollias, Spyros; Bertalanffy, Helmut

    2011-01-01

    A 16-year-old boy presented with an unusual case of a supratentorial, extraaxial small round blue cell tumor of the central nervous system, which was most likely a primitive neuroectodermal tumor (PNET). Preoperative computed tomography and magnetic resonance imaging showed a large multistage hematoma in the left central region. Intraoperatively, a small, superficial tumorous lesion was found between the sagittal sinus and a large cortical vein hidden by the hematoma. The histological diagnosis was PNET. This tumor is one of the most aggressive intracerebral tumors, not only in children, so treatment strategies must be early, profound, and interdisciplinary. This case represents an important example of atypical extraaxial appearance of this lesion, which should be considered in the differential diagnosis of cortical or subcortical hemorrhage, since complete resection of this lesion is critical for the successful treatment and outcome.

  2. Supratentorial cortical ependymoma: case series and review of the literature.

    PubMed

    Liu, Zhiguo; Li, Jing; Liu, Zhiyan; Wang, Qian; Famer, Peter; Mehta, Ashesh; Chalif, David; Wang, Yunyan; Li, Jian Yi

    2014-06-01

    Supratentorial cortical ependymoma (CE), a rare type of ependymoma, is located in the superficial cortex. We reported 11 patients (six female and five male) with CE. The age of the patients ranged from 2 to 63 years old with a median age of 47 years at the time of diagnosis. On MRI, enhancement was noted in all cases with solid appearance in six cases, and solid and cystic appearance in five cases. The frontal and parietal regions were the most common locations for CE. On histology, two were low-grade (WHO grade II) and nine were WHO grade III anaplastic ependymomas. Some tumors exhibited clear cell, spindle (tanycytic) and giant cell morphologies, as well as the classic ependymoma morphology. Dura-based tumor nodules and even tumor dissemination along the dura can be seen in CEs. Low grade CEs have a higher likelihood to present with seizures, a lower likelihood to cause brain edema, tumor recurrence and lower mortality than anaplastic ependymomas. While difficult, anaplastic CEs may be distinguished from glioblastoma by a clear interface between tumor and adjacent brain tissue, relative uniformity of tumor cell nuclei and immunopositivity for epithelial membrane antigen and/or CD99. As is the case for ependymomas in general, gross total resection is still the treatment of choice for CEs.

  3. Effectiveness of Endoscopic Surgery for Comatose Patients with Large Supratentorial Intracerebral Hemorrhages

    PubMed Central

    YAMASHIRO, Shigeo; HITOSHI, Yasuyuki; YOSHIDA, Akimasa; KURATSU, Jun-ichi

    2015-01-01

    To evaluate the effectiveness of endoscopic surgery for life-threatening large brain hemorrhage, we reviewed our empirical cases of comatose patients with large supratentorial intracerebral hemorrhage. Among 35 patients with putaminal or subcortical hemorrhage that was evacuated endoscopically, 14 cases (40%) presented both findings of neurological grade IV for severity and hematoma volume exceeding 70 mL in the recent 3 years (endoscope group), whereas 8 cases with the same conditions were treated by conventional craniotomy for the preceding 3-year period (craniotomy group). Between these two groups, mean age was higher and duration of surgery was shorter in the endoscope group, but no significant differences in hematoma size or evacuation rate were recognized. In the 10 cases that presented with signs of cerebral herniation (neurological grade IVb) and required emergent decompression, the preparation time for surgery tended to be shorter in the endoscope group, although the difference was not significant. Additional ventricular drainage was performed in 7 cases and showed a supplemental effect of reducing intracranial pressure (ICP). Consequently, all patients in the endoscope group were rescued without decompressive large craniectomy, even with symptoms of cerebral herniation. In conclusion, endoscopic surgery has the potential to offer an effective therapeutic option for comatose patients with large supratentorial intracerebral hemorrhages, matching conventional craniotomy for emergent treatment in terms of mortality and management of ICP. PMID:26369719

  4. Giant Dural Supratentorial Chondroma Generating the Question of How Large Can a Tumor Become Without Revealing Itself.

    PubMed

    Doukas, Alexandros; Tallo, Annamarie; Parvin, Richard; Hans, Volkmar; Daemi, Pooya; Cheko, Azad; Scholz, Martin; Petridis, Athanasios K

    2015-11-05

    Chondromas usually affect the small bones of hand and feet and account for only 0.5% of all intracranial tumors. We present a case of a giant, supratentorial meningeal chondroma in a 19-year old male patient and discuss the preoperative diagnostic findings as well as the appropriate treatment options. A 19-old male presented with headache, new onset of focal seizures and paresis of left upper extremity. Magnetic resonance imaging revealed a large right parietal tumor in the precentral region with local mass effect. The patient underwent right parietal craniotomy and gross total resection of the tumor. The histopathological report revealed a chondroma. Intradural supratentorial chondromas are extremely rare. As with other slow growing intracranial masses, they often reach a relatively large size before generating symptoms. Maximal surgical resection is the treatment of choice and if this is achieved no adjuvant therapy is necessary.

  5. Giant Dural Supratentorial Chondroma Generating the Question of How Large Can a Tumor Become Without Revealing Itself

    PubMed Central

    Doukas, Alexandros; Tallo, Annamarie; Parvin, Richard; Hans, Volkmar; Daemi, Pooya; Cheko, Azad; Scholz, Martin

    2015-01-01

    Chondromas usually affect the small bones of hand and feet and account for only 0.5% of all intracranial tumors. We present a case of a giant, supratentorial meningeal chondroma in a 19-year old male patient and discuss the preoperative diagnostic findings as well as the appropriate treatment options. A 19-old male presented with headache, new onset of focal seizures and paresis of left upper extremity. Magnetic resonance imaging revealed a large right parietal tumor in the precentral region with local mass effect. The patient underwent right parietal craniotomy and gross total resection of the tumor. The histopathological report revealed a chondroma. Intradural supratentorial chondromas are extremely rare. As with other slow growing intracranial masses, they often reach a relatively large size before generating symptoms. Maximal surgical resection is the treatment of choice and if this is achieved no adjuvant therapy is necessary. PMID:26918096

  6. Predictors of good outcome in medium to large spontaneous supratentorial intracerebral haemorrhages

    PubMed Central

    Castellanos, M; Leira, R; Tejada, J; Gil-Peralta, A; Davalos, A; Castillo, J; t for

    2005-01-01

    Objective: To determine potential predictors of good outcome in primary medium to large intracerebral haemorrhages (ICH) which could be useful for selecting patients for surgical procedures. Methods: Subjects were 138 patients with spontaneous hemispheric ICH >20 ml. They were non-surgically treated and were admitted consecutively to 15 hospitals within the first 12 hours of symptom onset (mean (SD), 5.8 (3.1) hours). Haematoma volume was measured on computed tomography (CT) at admission. Stroke severity was assessed by the Canadian stroke scale (CSS). Good outcome was defined as modified Rankin score ⩽2 at three months. Results: At the end of the follow up period, 45 patients (32.6%) had good outcome. Baseline stroke severity, systolic and diastolic blood pressure, body temperature, and acute phase reaction biochemical markers (ESR, C-reactive protein, fibrinogen, neutrophil count) were significantly associated with good outcome in bivariate analyses. Of the initial CT scan variables, intraventricular contamination, deep location, mass effect, and greater ICH volume were related to poor outcome. On multiple logistic regression analysis, cortical location of bleeding (odds ratio 3.79 (95% confidence interval 1.2 to 12.01); p = 0.023), high CSS score (OR 2.3 (1.6 to 3.1); p<0.0001), and low fibrinogen concentrations (OR 0.92 (0.87 to 0.97); p = 0.001) were independent predictors of good outcome. These three factors correctly classified 85% of patients. Conclusions: Good outcome in medium to large ICH can be predicted on admission by three readily assessable factors (CSS score, ICH location, and fibrinogen levels). These predictors may be helpful in selecting patients for surgical treatment. PMID:15834028

  7. Large-scale cortical networks and cognition.

    PubMed

    Bressler, S L

    1995-03-01

    The well-known parcellation of the mammalian cerebral cortex into a large number of functionally distinct cytoarchitectonic areas presents a problem for understanding the complex cortical integrative functions that underlie cognition. How do cortical areas having unique individual functional properties cooperate to accomplish these complex operations? Do neurons distributed throughout the cerebral cortex act together in large-scale functional assemblages? This review examines the substantial body of evidence supporting the view that complex integrative functions are carried out by large-scale networks of cortical areas. Pathway tracing studies in non-human primates have revealed widely distributed networks of interconnected cortical areas, providing an anatomical substrate for large-scale parallel processing of information in the cerebral cortex. Functional coactivation of multiple cortical areas has been demonstrated by neurophysiological studies in non-human primates and several different cognitive functions have been shown to depend on multiple distributed areas by human neuropsychological studies. Electrophysiological studies on interareal synchronization have provided evidence that active neurons in different cortical areas may become not only coactive, but also functionally interdependent. The computational advantages of synchronization between cortical areas in large-scale networks have been elucidated by studies using artificial neural network models. Recent observations of time-varying multi-areal cortical synchronization suggest that the functional topology of a large-scale cortical network is dynamically reorganized during visuomotor behavior.

  8. Cortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve Mapping

    PubMed Central

    Qiu, Anqi; Miller, Michael I.

    2010-01-01

    We present large deformation diffeomorphic metric curve mapping (LDDMM-Curve) for registering cortical hemispheres. We showed global cortical hemisphere matching and evaluated the mapping accuracy in five subregions of the cortex in fourteen MRI scans. PMID:18051058

  9. [Infratentorial hemorrhage following supratentorial surgery].

    PubMed

    Tomii, M; Nakajima, M; Ikeuchi, S; Ogawa, T; Abe, T

    1999-10-01

    Hemorrhage in regions remote from the site of initial intracranial operations is rare, but does occur. We report three cases of cerebellar hemorrhage that developed after supratentorial surgery, all of which had similar clinical findings and CT images. The first case was a 37-year-old man with a craniopharyngioma in the suprasellar lesion. Partial removal of the tumor was performed through frontal craniotomy and the translaminaterminals approach. A large quantity of cerebospinal fluid (CSF) was suctioned from the third ventricle during the operation, resulting in marked brain shrinkage. The second and third cases were 34- and 51-year-old women with unruptured right middle cerebral aneurysms. Clipping of the aneurysms through the pterional approach was performed in both cases. In the second case, CSF was suctioned in large quantity from the carotid and prechiasmal cistern at the operation, resulting in marked brain shrinkage. In the third case, however, only a small volume of CSF was suctioned from the carotid and prechiasmal cistern during the operation, and no marked brain shrinkage was observed. CT scan showed that the hematomas were located mainly in the subdural or the subarachnoid spaces over the cerebellar hemisphere and partially extending into the cerebellar cortex. The mechanism of cerebellar hemorrhage in these series of patients was thought to be multifactorial. The possible etiology for cerebellar hemorrhage in the three cases presented was examined, including the role of CSF suction during surgery and disturbance of venous circulation in the posterior fossa. Suction of the CSF may cause intracranial hypotension. Further reduction of intracranial pressure leads to an increased transluminal venous pressure. There was no episode of hypertension or disturbed blood coagulation during or after the operation. The preoperative angiogram also revealed no abnormality at the region of the posterior fossa. Neuroimaging of infratentorial hemorrhage after

  10. [Supratentorial arachnoidal cysts].

    PubMed

    Vizioli, L; Cerillo, A; Falivene, R; Mottolese, C; Tedeschi, G

    1983-01-01

    The AA., after having examined the various hypothesis reported in literature about the etiopathogenesis and the contrasting anatomical and pathological data concerning the arachnoid supratentorial cysts, point out the remarkable frequency of they malformative and above-all post-traumatic genesis. On the formation mechanism of this last type, they agree upon the supposition expressed by Taveras and Ransohoff in 1953. The AA., therefore, after having analysed the principal morphological and topographical aspects, pay attention to the present diagnostic possibilities, above all in radiological range, where the TAC represents, by this time, the examination of election compared with traditional assurances with means of contrast. It follows the analysis of the personal casuistry, consisting in 6 arachnoid supratentorial cysts, two of which clearly post-traumatic and two, very probably, of malformative genesis (for the coexistence of data in favour of both suppositions). The AA. draw these conclusions: the CT Scan is the only diagnostic means which permits an exact pre-operating diagnosis on the nature of the lesion; the surgical and, above all, anatomo-pathological reports assume an essential rule for an exact etiopathogenetic interpretation of the lesion examined.

  11. Discovering Cortical Folding Patterns in Neonatal Cortical Surfaces Using Large-Scale Dataset

    PubMed Central

    Meng, Yu; Li, Gang; Wang, Li; Lin, Weili; Gilmore, John H.

    2017-01-01

    The cortical folding of the human brain is highly complex and variable across individuals. Mining the major patterns of cortical folding from modern large-scale neuroimaging datasets is of great importance in advancing techniques for neuroimaging analysis and understanding the inter-individual variations of cortical folding and its relationship with cognitive function and disorders. As the primary cortical folding is genetically influenced and has been established at term birth, neonates with the minimal exposure to the complicated postnatal environmental influence are the ideal candidates for understanding the major patterns of cortical folding. In this paper, for the first time, we propose a novel method for discovering the major patterns of cortical folding in a large-scale dataset of neonatal brain MR images (N = 677). In our method, first, cortical folding is characterized by the distribution of sulcal pits, which are the locally deepest points in cortical sulci. Because deep sulcal pits are genetically related, relatively consistent across individuals, and also stable during brain development, they are well suitable for representing and characterizing cortical folding. Then, the similarities between sulcal pit distributions of any two subjects are measured from spatial, geometrical, and topological points of view. Next, these different measurements are adaptively fused together using a similarity network fusion technique, to preserve their common information and also catch their complementary information. Finally, leveraging the fused similarity measurements, a hierarchical affinity propagation algorithm is used to group similar sulcal folding patterns together. The proposed method has been applied to 677 neonatal brains (the largest neonatal dataset to our knowledge) in the central sulcus, superior temporal sulcus, and cingulate sulcus, and revealed multiple distinct and meaningful folding patterns in each region. PMID:28229131

  12. Individualized diffeomorphic mapping of brains with large cortical infarcts.

    PubMed

    Soon, Hock Wei; Qiu, Anqi

    2015-01-01

    Whole brain mapping of stroke patients with large cortical infarcts is not trivial due to the complexity of infarcts' anatomical location and appearance in magnetic resonance image. In this study, we proposed an individualized diffeomorphic mapping framework for solving this problem. This framework is based on our recent work of large deformation diffeomorphic metric mapping (LDDMM) in Du et al. (2011) and incorporates anatomical features, such as sulcal/gyral curves, cortical surfaces, brain intensity image, and masks of infarcted regions, in order to align a normal brain to the brain of stroke patients. We applied this framework to synthetic data and data of stroke patients and validated the mapping accuracy in terms of the alignment of gyral/sulcal curves, sulcal regions, and brain segmentation. Our results revealed that this framework provided comparable mapping results for stroke patients and healthy controls, suggesting the importance of incorporating individualized anatomical features in whole brain mapping of brains with large cortical infarcts.

  13. Postoperative analgesia for supratentorial craniotomy.

    PubMed

    Dilmen, Ozlem Korkmaz; Akcil, Eren Fatma; Tunali, Yusuf; Karabulut, Esra Sultan; Bahar, Mois; Altindas, Fatis; Vehid, Hayriye; Yentur, Ercument

    2016-07-01

    The prevalence of moderate to severe pain is high in patients following craniotomy. Although optimal analgesic therapy is mandatory, there is no consensus regarding analgesic regimen for post-craniotomy pain exists. This study aimed to investigate the effects of morphine and non-opioid analgesics on postcraniotomy pain. This prospective, randomized, double blind, placebo controlled study included eighty three patients (ASA 1, II, and III) scheduled for elective supratentorial craniotomy. Intravenous dexketoprofen, paracetamol and metamizol were investigated for their effects on pain intensity, morphine consumption and morphine related side effects during the first 24h following supratentorial craniotomy. Patients were treated with morphine based patient controlled analgesia (PCA) for 24h following surgery and randomized to receive supplemental IV dexketoprofen 50mg, paracetamol 1g, metamizol 1g or placebo. The primary endpoint was pain intensity, secondary endpoint was the effects on morphine consumption and related side effects. When the whole study period was analyzed with repeated measures of ANOVA, the pain intensity, cumulative morphine consumption and related side effects were not different among the groups (p>0.05). This study showed that the use of morphine based PCA prevented moderate to severe postoperative pain without causing any life threatening side effects in patients undergoing supratentorial craniotomy with a vigilant follow up during postoperative 24h. Although we could not demonstrate statistically significant effect of supplemental analgesics on morphine consumption, it was lower in dexketoprofen and metamizol groups than control group. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Familial infantile cortical hyperostosis in a large Canadian family.

    PubMed Central

    Maclachlan, A. K.; Gerrard, J. W.; Houston, C. S.; Ives, E. J.

    1984-01-01

    Infantile cortical hyperostosis is a rare proliferative bone disease affecting infants under the age of 6 months. In 1961 a large family of French-Canadian origin in which 14 children in three generations were affected was described. Since then 20 new cases have been found in this family. This is the largest familial aggregation of this disease reported in the literature to date. On the basis of the findings in this pedigree, the familial form of the disease appears to be transmitted by a single autosomal dominant gene with incomplete penetrance and variable expressivity. Images Fig. 2 Fig. 3 PMID:6370402

  15. Analysis of supratentorial cystic abnormalities using in utero MR imaging

    PubMed Central

    Warner, Hannah M

    2016-01-01

    Objective: Our anecdotal experience from foetal neuroimaging studies suggests that there are often significant disagreements between the findings of ultrasonography (USS) and in utero MR (iuMR) imaging in cases of antenatally detected supratentorial extra-axial cysts. Although this is a relatively rare clinical situation, it warrants further investigation because of the high risk of other intracranial abnormalities that are likely to cause long-term neurodevelopmental problems. Methods: We reviewed 957 consecutive referrals for iuMR of the foetal brain over a 3.5-year period and studied all cases where the referral from USS described supratentorial extra-axial cysts in the foetus. The iuMR imaging was reviewed, and a comparison between the results of the two examinations was made. Results: Supratentorial extra-axial cysts were an unusual referral for iuMR occurring in only 13/957 (1.4%) of cases. The findings on USS and iuMR imaging were conflicting in all 13 cases with intracranial pathology being excluded on iuMR imaging in 4 cases and more significant pathology being shown in 9 cases. Abnormalities of the corpus callosum were recognized in association with a cyst in eight cases, and this was recognized in only two cases on USS. Six of those cases also had abnormalities of cortical formation. Conclusion: iuMR imaging should be used in the assessment of pregnancies in which a supratentorial extra-axial cyst has been detected on USS. This is based on the improved primary diagnosis and a high rate of associated brain abnormalities not detected on USS. Advances in knowledge: Our retrospective observational study examines a range of foetal intracranial abnormalities which are better defined using iuMRI. This is a previously described spectrum of neurodevelopmental anomalies which we suggest would benefit from MRI. PMID:26577541

  16. Hierarchical features of large-scale cortical connectivity

    NASA Astrophysics Data System (ADS)

    da F. Costa, L.; Sporns, O.

    2005-12-01

    The analysis of complex networks has revealed patterns of organization in a variety of natural and artificial systems, including neuronal networks of the brain at multiple scales. In this paper, we describe a novel analysis of the large-scale connectivity between regions of the mammalian cerebral cortex, utilizing a set of hierarchical measurements proposed recently. We examine previously identified functional clusters of brain regions in macaque visual cortex and cat cortex and find significant differences between such clusters in terms of several hierarchical measures, revealing differences in how these clusters are embedded in the overall cortical architecture. For example, the ventral cluster of visual cortex maintains structurally more segregated, less divergent connections than the dorsal cluster, which may point to functionally different roles of their constituent brain regions.

  17. Photodynamic therapy of supratentorial gliomas

    NASA Astrophysics Data System (ADS)

    Muller, Paul J.; Wilson, Brian C.

    1997-05-01

    We are reporting the results form intraoperative intracavitary PDT treatment in 56 patients with recurrent supratentorial gliomas who had failed previous surgery and radiotherapy. These patients received 2mg/kg Photofin iv. 12-36 hours prior to surgical resection of their tumor or tumor cyst drainage. The median survival times in weeks for glioblastoma (GBM), malignant astrocytoma (MA), malignant mixed astrocytoma-oligodendroglioma and ependymoma were 30, 40, >56 and >174 weeks, respectively. Eight patients with recurrent GBM who received >60 J/cm2 had a median survival of 58 weeks and 24 patients who received <60 J/cm2 survived 29 weeks. The survival of patients with recurrent glioblastoma who undergo surgical treatment alone is only 20 weeks. We are also reporting the results of PDT treatment in 20 patients with newly diagnosed MA or GBM treated with intracavitary Photofin-PDT at the time of their initial craniotomy. The median survival of the whole cohort was 44 weeks with a 1 and 2 year survival of 40 percent and 15 percent, respectively. The median survival of patients with GBM was 37 weeks with a 1 and 2 year actuarial survival of 35 percent and 0 percent, respectively. The median survival of patients with MA as 48 weeks with a 1 and 2 year actuarial survival of 44 percent and 33 percent, respectively. Six patients with a Karnofsky score of >70 who received a light dose of >1260J had a median survival of 92 weeks with a 1 and 2 year survival of 83 percent and 33 percent, respectively. The mortality rate in our total series of 93 PDT treatments or brain tumor is 3 percent. The combined serious mortality-morbidity rate is 8 percent.

  18. Dysphagia Post Subcortical and Supratentorial Stroke.

    PubMed

    Wan, Ping; Chen, Xuhui; Zhu, Lequn; Xu, Shuangjin; Huang, Li; Li, Xiangcui; Ye, Qing; Ding, Ruiying

    2016-01-01

    Studies have recognized that the damage in the subcortical and supratentorial regions may affect voluntary and involuntary aspects of the swallowing function. The current study attempted to explore the dysphagia characteristics in patients with subcortical and supratentorial stroke. Twelve post first or second subcortical and supratentorial stroke patients were included in the study. The location of the stroke was ascertained by computed tomography and magnetic resonance imaging. The characteristics of swallowing disorder were assessed by video fluoroscopic swallowing assessment/fiberoptic endoscopic evaluation of swallowing. The following main parameters were analyzed: oral transit time, pharyngeal delay time, presence of cricopharyngeal muscle achalasia (CMA), distance of laryngeal elevation, the amounts of vallecular residue and pyriform sinus residue (PSR), and the extent of pharyngeal contraction. Eighty-three percent of the 12 patients were found suffering from pharyngeal dysphagia, with 50% having 50%-100% PSRs, 50% having pharyngeal delay, and 41.6% cases demonstrating CMA. Simple regression analysis showed PSRs were most strongly associated with CMA. Pharyngeal delay in the study can be caused by infarcts of basal ganglia/thalamus, infarcts of sensory tract, infarcts of swallowing motor pathways in the centrum semiovale, or a combination of the three. Subcortical and supratentorial stroke may result in pharyngeal dysphagia such as PSR and pharyngeal delay. PSR was mainly caused by CMA. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  19. Surgery for Patients With Spontaneous Deep Supratentorial Intracerebral Hemorrhage

    PubMed Central

    Zheng, Jun; Li, Hao; Zhao, He-Xiang; Guo, Rui; Lin, Sen; Dong, Wei; Ma, Lu; Fang, Yuan; Tian, Meng; Liu, Ming; You, Chao

    2016-01-01

    .014). Surgery could reduce the short-term mortality as well as long-term mortality in patients with spontaneous deep supratentorial hemorrhage. Moreover, surgery might improve the functional outcome in patients with large hematoma or with IVH compared with conservative treatment. Surgery might be a beneficial choice for part of the patients with spontaneous deep supratentorial hemorrhage, but further detailed research is still needed. PMID:26986116

  20. Heritability analysis of surface-based cortical thickness estimation on a large twin cohort

    NASA Astrophysics Data System (ADS)

    Shen, Kaikai; Doré, Vincent; Rose, Stephen; Fripp, Jurgen; McMahon, Katie L.; de Zubicaray, Greig I.; Martin, Nicholas G.; Thompson, Paul M.; Wright, Margaret J.; Salvado, Olivier

    2015-03-01

    The aim of this paper is to assess the heritability of cerebral cortex, based on measurements of grey matter (GM) thickness derived from structural MR images (sMRI). With data acquired from a large twin cohort (328 subjects), an automated method was used to estimate the cortical thickness, and EM-ICP surface registration algorithm was used to establish the correspondence of cortex across the population. An ACE model was then employed to compute the heritability of cortical thickness. Heritable cortical thickness measures various cortical regions, especially in frontal and parietal lobes, such as bilateral postcentral gyri, superior occipital gyri, superior parietal gyri, precuneus, the orbital part of the right frontal gyrus, right medial superior frontal gyrus, right middle occipital gyrus, right paracentral lobule, left precentral gyrus, and left dorsolateral superior frontal gyrus.

  1. Oscillations and Synchrony in Large-scale Cortical Network Models

    DTIC Science & Technology

    2008-06-17

    Intrinsic neuronal and circuit properties control the responses of large ensembles of neurons by creating spatiotemporal patterns of ...map-based models) to simulate the intrinsic dynamics of biological neurons . These phenomenological models were designed to capture the main response...function of parameters that affect synaptic interactions and intrinsic states of the neurons . Keywords

  2. Dysembryoplastic Neuroepithelial Tumor of the Septum Pellucidum and the Supratentorial Midline: Histopathologic, Neuroradiologic, and Molecular Features of 7 Cases.

    PubMed

    Gessi, Marco; Hattingen, Elke; Dörner, Evelyn; Goschzik, Tobias; Dreschmann, Verena; Waha, Andreas; Pietsch, Torsten

    2016-06-01

    Dysembryoplastic neuroepithelial tumors (DNTs) are one of the most common epilepsy-associated low-grade glioneuronal tumors of the central nervous system. Although most DNTs occur in the cerebral cortex, DNT-like tumors with unusual intraventricular or periventricular localizations have been reported. Most of them involve the septum pellucidum and the foramen of Monro. In this study, we have described the neuroradiologic, histopathologic, and molecular features of 7 cases (4 female and 3 male; patient age range, 3 to 34 y; mean age, 16.7 y). The tumors, all localized near the supratentorial midline structures in proximity to the foramen of Monro and septum pellucidum, appeared in magnetic resonance imaging as well-delimited cystic lesions with cerebrospinal fluid-like signal on T1-weighted and T2-weighted images, some of them with typical fluid-attenuated inversion recovery ring sign. Histologically, they shared features with classic cortical DNTs but did not display aspects of multinodularity. From a molecular point of view the cases investigated did not show KIAA1549-BRAF fusions or FGFR1 mutations, alterations otherwise observed in pilocytic astrocytomas, or MYB and MYBL1 alterations that have been identified in a large group of pediatric low-grade gliomas. Moreover, BRAF mutations, which so far represent the most common molecular alteration found in cortical DNTs, were absent in this group of rare periventricular tumors.

  3. Influence of wiring cost on the large-scale architecture of human cortical connectivity.

    PubMed

    Samu, David; Seth, Anil K; Nowotny, Thomas

    2014-04-01

    In the past two decades some fundamental properties of cortical connectivity have been discovered: small-world structure, pronounced hierarchical and modular organisation, and strong core and rich-club structures. A common assumption when interpreting results of this kind is that the observed structural properties are present to enable the brain's function. However, the brain is also embedded into the limited space of the skull and its wiring has associated developmental and metabolic costs. These basic physical and economic aspects place separate, often conflicting, constraints on the brain's connectivity, which must be characterized in order to understand the true relationship between brain structure and function. To address this challenge, here we ask which, and to what extent, aspects of the structural organisation of the brain are conserved if we preserve specific spatial and topological properties of the brain but otherwise randomise its connectivity. We perform a comparative analysis of a connectivity map of the cortical connectome both on high- and low-resolutions utilising three different types of surrogate networks: spatially unconstrained ('random'), connection length preserving ('spatial'), and connection length optimised ('reduced') surrogates. We find that unconstrained randomisation markedly diminishes all investigated architectural properties of cortical connectivity. By contrast, spatial and reduced surrogates largely preserve most properties and, interestingly, often more so in the reduced surrogates. Specifically, our results suggest that the cortical network is less tightly integrated than its spatial constraints would allow, but more strongly segregated than its spatial constraints would necessitate. We additionally find that hierarchical organisation and rich-club structure of the cortical connectivity are largely preserved in spatial and reduced surrogates and hence may be partially attributable to cortical wiring constraints. In contrast

  4. Influence of Wiring Cost on the Large-Scale Architecture of Human Cortical Connectivity

    PubMed Central

    Samu, David; Seth, Anil K.; Nowotny, Thomas

    2014-01-01

    In the past two decades some fundamental properties of cortical connectivity have been discovered: small-world structure, pronounced hierarchical and modular organisation, and strong core and rich-club structures. A common assumption when interpreting results of this kind is that the observed structural properties are present to enable the brain's function. However, the brain is also embedded into the limited space of the skull and its wiring has associated developmental and metabolic costs. These basic physical and economic aspects place separate, often conflicting, constraints on the brain's connectivity, which must be characterized in order to understand the true relationship between brain structure and function. To address this challenge, here we ask which, and to what extent, aspects of the structural organisation of the brain are conserved if we preserve specific spatial and topological properties of the brain but otherwise randomise its connectivity. We perform a comparative analysis of a connectivity map of the cortical connectome both on high- and low-resolutions utilising three different types of surrogate networks: spatially unconstrained (‘random’), connection length preserving (‘spatial’), and connection length optimised (‘reduced’) surrogates. We find that unconstrained randomisation markedly diminishes all investigated architectural properties of cortical connectivity. By contrast, spatial and reduced surrogates largely preserve most properties and, interestingly, often more so in the reduced surrogates. Specifically, our results suggest that the cortical network is less tightly integrated than its spatial constraints would allow, but more strongly segregated than its spatial constraints would necessitate. We additionally find that hierarchical organisation and rich-club structure of the cortical connectivity are largely preserved in spatial and reduced surrogates and hence may be partially attributable to cortical wiring constraints. In

  5. Local Fibrinolysis in Spontaneous Supratentorial Hematomas: Comparison with Surgical and Medical Treatment

    PubMed Central

    Condrea, Eugeniu; Timirgaz, Valeriu; Groppa, Stanislav; Codreanu, Ion; Rotaru, Natalia

    2016-01-01

    Objective To evaluate the effectiveness of minimally invasive craniopuncture with local fibrinolysis in the management of supratentorial spontaneous intracerebral hemorrhage (SICH). Methods The study included 218 consecutive patients with supratentorial SICH who were assigned to one of three groups: treated with minimally invasive craniopuncture with local fibrinolysis, treated with craniotomy or other minimally invasive techniques without local fibrinolysis, or receiving conservative management alone. Results Minimally invasive craniopuncture with local fibrinolysis was associated with a lower rate of assisted ventilation, a shorter period of in-hospital stay, a more frequent initiation of early rehabilitation, and a lower mortality rate at all periods of assessment. The overall mortality at 12 months was 19.4% (vs. 50.0 and 33.3% in the two other therapy groups). Lobar (subcortical and cortical) SICHs treated with local fibrinolysis had an overall mortality of 4.8% (vs. 43.5 and 41.7% in the two other therapy groups). On the other hand, SICHs having mixed (basal ganglia and lobar) locations treated with medical therapy alone had an overall mortality of 28.6%, while associated surgery with or without local fibrinolysis increased the overall mortality to over 65%. Conclusions The study demonstrated the applicability of minimally invasive craniopuncture with local fibrinolysis for the management of supratentorial SICHs and the advantages it may have in certain categories of patients. The method proved particularly useful in lobar SICHs, being associated with the lowest mortality. Mixed SICHs do not represent a predilection for surgical interventions; however, the results related to mixed supratentorial locations need confirmation in larger cohorts. PMID:27781045

  6. Dual extradural cortical stimulation in chronic stroke patients with large infarcts: technical case report.

    PubMed

    Shin, Yong-Il; Kim, Hyoungihl; Moon, Seong-Keun; Kim, Hyojoon; Yun, Yong-Soon; Chung, Gyung-Ho

    2010-06-01

    Recent works on extradural cortical stimulation have been successful in improving neurological recovery in chronic stroke patients. On the other hand, single perirolandic stimulations are often associated with disappointing results. We report two cases of chronic stroke in which the magnitude of infarct was too large to be improved with single perirolandic stimulation. Patient 1 had severe hemiplegia associated with large cortical infarct in the right frontoparietal area. The patient could neither stand independently or walk. Patient 2 had hemiplegia and aphasia due to cortical infarct in the left middle cerebral artery territory. Both patients had intensive rehabilitative training for more than 6 months with no beneficial results. Two paddle electrodes covering frontal and parietal area were implanted, followed by dual cortical stimulation with concurrent rehabilitative training in patient 1. After 6 months of stimulation, the patient could walk with a good posture. Two paddle electrodes were implanted to cover pre-motor and motor cortex in patient 2. After similar treatment, the motor function was markedly improved. Dual cortex stimulation, which acts on more diffuse areas or functionally related areas, is beneficial to promote the motor recovery in chronic stroke patients with large infarcts.

  7. Large Deformation Multiresolution Diffeomorphic Metric Mapping for Multiresolution Cortical Surfaces: A Coarse-to-Fine Approach.

    PubMed

    Tan, Mingzhen; Qiu, Anqi

    2016-09-01

    Brain surface registration is an important tool for characterizing cortical anatomical variations and understanding their roles in normal cortical development and psychiatric diseases. However, surface registration remains challenging due to complicated cortical anatomy and its large differences across individuals. In this paper, we propose a fast coarse-to-fine algorithm for surface registration by adapting the large diffeomorphic deformation metric mapping (LDDMM) framework for surface mapping and show improvements in speed and accuracy via a multiresolution analysis of surface meshes and the construction of multiresolution diffeomorphic transformations. The proposed method constructs a family of multiresolution meshes that are used as natural sparse priors of the cortical morphology. At varying resolutions, these meshes act as anchor points where the parameterization of multiresolution deformation vector fields can be supported, allowing the construction of a bundle of multiresolution deformation fields, each originating from a different resolution. Using a coarse-to-fine approach, we show a potential reduction in computation cost along with improvements in sulcal alignment when compared with LDDMM surface mapping.

  8. Anatomical connectivity and the resting state activity of large cortical networks

    PubMed Central

    Pinotsis, D.A.; Hansen, E.; Friston, K.J.; Jirsa, V.K.

    2013-01-01

    This paper uses mathematical modelling and simulations to explore the dynamics that emerge in large scale cortical networks, with a particular focus on the topological properties of the structural connectivity and its relationship to functional connectivity. We exploit realistic anatomical connectivity matrices (from diffusion spectrum imaging) and investigate their capacity to generate various types of resting state activity. In particular, we study emergent patterns of activity for realistic connectivity configurations together with approximations formulated in terms of neural mass or field models. We find that homogenous connectivity matrices, of the sort of assumed in certain neural field models give rise to damped spatially periodic modes, while more localised modes reflect heterogeneous coupling topologies. When simulating resting state fluctuations under realistic connectivity, we find no evidence for a spectrum of spatially periodic patterns, even when grouping together cortical nodes into communities, using graph theory. We conclude that neural field models with translationally invariant connectivity may be best applied at the mesoscopic scale and that more general models of cortical networks that embed local neural fields, may provide appropriate models of macroscopic cortical dynamics over the whole brain. PMID:23085498

  9. An Efficient Simulation Environment for Modeling Large-Scale Cortical Processing

    PubMed Central

    Richert, Micah; Nageswaran, Jayram Moorkanikara; Dutt, Nikil; Krichmar, Jeffrey L.

    2011-01-01

    We have developed a spiking neural network simulator, which is both easy to use and computationally efficient, for the generation of large-scale computational neuroscience models. The simulator implements current or conductance based Izhikevich neuron networks, having spike-timing dependent plasticity and short-term plasticity. It uses a standard network construction interface. The simulator allows for execution on either GPUs or CPUs. The simulator, which is written in C/C++, allows for both fine grain and coarse grain specificity of a host of parameters. We demonstrate the ease of use and computational efficiency of this model by implementing a large-scale model of cortical areas V1, V4, and area MT. The complete model, which has 138,240 neurons and approximately 30 million synapses, runs in real-time on an off-the-shelf GPU. The simulator source code, as well as the source code for the cortical model examples is publicly available. PMID:22007166

  10. An efficient simulation environment for modeling large-scale cortical processing.

    PubMed

    Richert, Micah; Nageswaran, Jayram Moorkanikara; Dutt, Nikil; Krichmar, Jeffrey L

    2011-01-01

    We have developed a spiking neural network simulator, which is both easy to use and computationally efficient, for the generation of large-scale computational neuroscience models. The simulator implements current or conductance based Izhikevich neuron networks, having spike-timing dependent plasticity and short-term plasticity. It uses a standard network construction interface. The simulator allows for execution on either GPUs or CPUs. The simulator, which is written in C/C++, allows for both fine grain and coarse grain specificity of a host of parameters. We demonstrate the ease of use and computational efficiency of this model by implementing a large-scale model of cortical areas V1, V4, and area MT. The complete model, which has 138,240 neurons and approximately 30 million synapses, runs in real-time on an off-the-shelf GPU. The simulator source code, as well as the source code for the cortical model examples is publicly available.

  11. Supratentorial endodermal cysts - Report of two cases

    PubMed Central

    Rangarajan, Vithal; Mahore, Amit; Patil, Manoj Kashinath; Shendarkar, Ashwini Dnyandaevrao

    2016-01-01

    We describe two rare cases of frontal cystic lesions presenting with symptoms and signs of raised intracranial pressure. Both had a preoperative diagnosis of an arachnoid cyst and were subjected to a craniotomy with marsupialization of the cyst. However, the histology confirmed them to be an endodermal cyst (EC) on both occasions. Both the patients have been closely followed with no recurrence of symptoms. ECs of the central nervous system are usually reported in the spinal canal, mid-line posterior fossa, and the suprasellar regions. Supratentorial and non-midline ECs are rare, with only about 22 cases previously reported in literature. We discuss both the cases and review the relevant literature. PMID:27366267

  12. Patterns of Brain Infiltration And Secondary Structure Formation in Supratentorial Ependymal Tumors

    PubMed Central

    Lehman, Norman L.

    2009-01-01

    Ependymomas are generally considered to be non-infiltrative tumors that have discrete borders with adjacent brain tissue. Most occur in the posterior fossa or spinal cord. Supratentorial ependymal tumors arise near the ventricular system, or more rarely, within the cerebral white matter or cortex. Presented here are six supratentorial ependymal tumors, three that primarily involve the cerebral cortex and three that extend into the cortex from the underlying white matter. By microscopy, all of these tumors locally infiltrate the cortex and/or white matter along small blood vessels and axonal fiber tracts. They also form other glioma secondary structures including perineuronal tumor cell satellitosis and subpial tumor cell mounds. The three cortical ependymal tumors show a spectrum of features ranging from conventional and clear cell ependymoma-like patterns to more angiocentric glioma-like histology. Since ependymal tumors generally have a significantly better prognosis than other infiltrating gliomas, recognition of their capacity to infiltrate adjacent cortex and white matter is important to prevent the misdiagnosis of oligodendroglioma, astrocytoma, or infiltrating glioma, not otherwise specified. Cortical ependymomas and angiocentric gliomas may comprise a group of locally infiltrative ependymal tumors that are associated with an excellent prognosis following gross total surgical resection. PMID:18716554

  13. Patterns of brain infiltration and secondary structure formation in supratentorial ependymal tumors.

    PubMed

    Lehman, Norman L

    2008-09-01

    Ependymomas are generally considered to be noninfiltrative tumors that have discrete borders with adjacent brain tissue. Most occur in the posterior fossa or spinal cord. Supratentorial ependymal tumors arise near the ventricular system or, more rarely, within the cerebral white matter or cortex. Presented here are 6 supratentorial ependymal tumors, 3 that primarily involve the cerebral cortex and 3 that extend into the cortex from the underlying white matter. By microscopy, all of these tumors locally infiltrate the cortex and/or white matter along small blood vessels and axonal fiber tracts. They also form other glioma secondary structures including perineuronal tumor cell satellitosis and subpial tumor cell mounds. The 3 cortical ependymal tumors show a spectrum of features ranging from conventional and clear-cell ependymoma-like patterns to more angiocentric glioma-like histology. Because ependymal tumors generally have a significantly better prognosis than other infiltrating gliomas, recognition of their capacity to infiltrate adjacent cortex and white matter is important to prevent the misdiagnosis of oligodendroglioma, astrocytoma, or infiltrating glioma, not otherwise specified. Cortical ependymomas and angiocentric gliomas may comprise a group of locally infiltrative ependymal tumors that are associated with an excellent prognosis after gross total surgical resection.

  14. Specificities of Awake Craniotomy and Brain Mapping in Children for Resection of Supratentorial Tumors in the Language Area.

    PubMed

    Delion, Matthieu; Terminassian, Aram; Lehousse, Thierry; Aubin, Ghislaine; Malka, Jean; N'Guyen, Sylvie; Mercier, Philippe; Menei, Philippe

    2015-12-01

    In the pediatric population, awake craniotomy began to be used for the resection of brain tumor located close to eloquent areas. Some specificities must be taken into account to adapt this method to children. The aim of this clinical study is to not only confirm the feasibility of awake craniotomy and language brain mapping in the pediatric population but also identify the specificities and necessary adaptations of the procedure. Six children aged 11 to 16 were operated on while awake under local anesthesia with language brain mapping for supratentorial brain lesions (tumor and cavernoma). The preoperative planning comprised functional magnetic resonance imaging (MRI) and neuropsychologic and psychologic assessment. The specific preoperative preparation is clearly explained including hypnosis conditioning and psychiatric evaluation. The success of the procedure was based on the ability to perform the language brain mapping and the tumor removal without putting the patient to sleep. We investigated the pediatric specificities, psychological experience, and neuropsychologic follow-up. The children experienced little anxiety, probably in large part due to the use of hypnosis. We succeeded in doing the cortical-subcortical mapping and removing the tumor without putting the patient to sleep in all cases. The psychological experience was good, and the neuropsychologic follow-up showed a favorable evolution. Preoperative preparation and hypnosis in children seemed important for performing awake craniotomy and contributing language brain mapping with the best possible psychological experience. The pediatrics specificities are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Reward-related cortical inputs define a large striatal region in primates that interface with associative cortical connections, providing a substrate for incentive-based learning.

    PubMed

    Haber, Suzanne N; Kim, Ki-Sok; Mailly, Philippe; Calzavara, Roberta

    2006-08-09

    The anterior cingulate and orbital cortices and the ventral striatum process different aspects of reward evaluation, whereas the dorsolateral prefrontal cortex and the dorsal striatum are involved in cognitive function. Collectively, these areas are critical to decision making. We mapped the striatal area that receives information about reward evaluation. We also explored the extent to which terminals from reward-related cortical areas converge in the striatum with those from cognitive regions. Using three-dimensional-rendered reconstructions of corticostriatal projection fields along with two-dimensional chartings, we demonstrate the reward and cognitive territories in the primate striatum and show the convergence between these cortical inputs. The results show two labeling patterns: a focal projection field that consists of densely distributed terminal patches, and a diffuse projection consisting of clusters of fibers, extending throughout a wide area of the striatum. Together, these projection fields demonstrate a remarkably large, rostral, reward-related striatal territory that reaches into the dorsal striatum. Fibers from different reward-processing and cognitive cortical areas occupy both separate and converging territories. Furthermore, the diffuse projection may serve a separate integrative function by broadly disseminating general cortical activity. These findings show that the rostral striatum is in a unique position to mediate different aspects of incentive learning. Furthermore, areas of convergence may be particularly sensitive to dopamine modulation during decision making and habit formation.

  16. Reliability and statistical power analysis of cortical and subcortical FreeSurfer metrics in a large sample of healthy elderly.

    PubMed

    Liem, Franziskus; Mérillat, Susan; Bezzola, Ladina; Hirsiger, Sarah; Philipp, Michel; Madhyastha, Tara; Jäncke, Lutz

    2015-03-01

    FreeSurfer is a tool to quantify cortical and subcortical brain anatomy automatically and noninvasively. Previous studies have reported reliability and statistical power analyses in relatively small samples or only selected one aspect of brain anatomy. Here, we investigated reliability and statistical power of cortical thickness, surface area, volume, and the volume of subcortical structures in a large sample (N=189) of healthy elderly subjects (64+ years). Reliability (intraclass correlation coefficient) of cortical and subcortical parameters is generally high (cortical: ICCs>0.87, subcortical: ICCs>0.95). Surface-based smoothing increases reliability of cortical thickness maps, while it decreases reliability of cortical surface area and volume. Nevertheless, statistical power of all measures benefits from smoothing. When aiming to detect a 10% difference between groups, the number of subjects required to test effects with sufficient power over the entire cortex varies between cortical measures (cortical thickness: N=39, surface area: N=21, volume: N=81; 10mm smoothing, power=0.8, α=0.05). For subcortical regions this number is between 16 and 76 subjects, depending on the region. We also demonstrate the advantage of within-subject designs over between-subject designs. Furthermore, we publicly provide a tool that allows researchers to perform a priori power analysis and sensitivity analysis to help evaluate previously published studies and to design future studies with sufficient statistical power.

  17. Inferring cortical function in the mouse visual system through large-scale systems neuroscience.

    PubMed

    Hawrylycz, Michael; Anastassiou, Costas; Arkhipov, Anton; Berg, Jim; Buice, Michael; Cain, Nicholas; Gouwens, Nathan W; Gratiy, Sergey; Iyer, Ramakrishnan; Lee, Jung Hoon; Mihalas, Stefan; Mitelut, Catalin; Olsen, Shawn; Reid, R Clay; Teeter, Corinne; de Vries, Saskia; Waters, Jack; Zeng, Hongkui; Koch, Christof

    2016-07-05

    The scientific mission of the Project MindScope is to understand neocortex, the part of the mammalian brain that gives rise to perception, memory, intelligence, and consciousness. We seek to quantitatively evaluate the hypothesis that neocortex is a relatively homogeneous tissue, with smaller functional modules that perform a common computational function replicated across regions. We here focus on the mouse as a mammalian model organism with genetics, physiology, and behavior that can be readily studied and manipulated in the laboratory. We seek to describe the operation of cortical circuitry at the computational level by comprehensively cataloging and characterizing its cellular building blocks along with their dynamics and their cell type-specific connectivities. The project is also building large-scale experimental platforms (i.e., brain observatories) to record the activity of large populations of cortical neurons in behaving mice subject to visual stimuli. A primary goal is to understand the series of operations from visual input in the retina to behavior by observing and modeling the physical transformations of signals in the corticothalamic system. We here focus on the contribution that computer modeling and theory make to this long-term effort.

  18. Inferring cortical function in the mouse visual system through large-scale systems neuroscience

    PubMed Central

    Hawrylycz, Michael; Anastassiou, Costas; Arkhipov, Anton; Berg, Jim; Buice, Michael; Cain, Nicholas; Gouwens, Nathan W.; Gratiy, Sergey; Iyer, Ramakrishnan; Lee, Jung Hoon; Mihalas, Stefan; Mitelut, Catalin; Olsen, Shawn; Reid, R. Clay; Teeter, Corinne; de Vries, Saskia; Waters, Jack; Zeng, Hongkui; Koch, Christof

    2016-01-01

    The scientific mission of the Project MindScope is to understand neocortex, the part of the mammalian brain that gives rise to perception, memory, intelligence, and consciousness. We seek to quantitatively evaluate the hypothesis that neocortex is a relatively homogeneous tissue, with smaller functional modules that perform a common computational function replicated across regions. We here focus on the mouse as a mammalian model organism with genetics, physiology, and behavior that can be readily studied and manipulated in the laboratory. We seek to describe the operation of cortical circuitry at the computational level by comprehensively cataloging and characterizing its cellular building blocks along with their dynamics and their cell type-specific connectivities. The project is also building large-scale experimental platforms (i.e., brain observatories) to record the activity of large populations of cortical neurons in behaving mice subject to visual stimuli. A primary goal is to understand the series of operations from visual input in the retina to behavior by observing and modeling the physical transformations of signals in the corticothalamic system. We here focus on the contribution that computer modeling and theory make to this long-term effort. PMID:27382147

  19. Large-scale imaging of cortical dynamics during sensory perception and behavior.

    PubMed

    Wekselblatt, Joseph B; Flister, Erik D; Piscopo, Denise M; Niell, Cristopher M

    2016-06-01

    Sensory-driven behaviors engage a cascade of cortical regions to process sensory input and generate motor output. To investigate the temporal dynamics of neural activity at this global scale, we have improved and integrated tools to perform functional imaging across large areas of cortex using a transgenic mouse expressing the genetically encoded calcium sensor GCaMP6s, together with a head-fixed visual discrimination behavior. This technique allows imaging of activity across the dorsal surface of cortex, with spatial resolution adequate to detect differential activity in local regions at least as small as 100 μm. Imaging during an orientation discrimination task reveals a progression of activity in different cortical regions associated with different phases of the task. After cortex-wide patterns of activity are determined, we demonstrate the ability to select a region that displayed conspicuous responses for two-photon microscopy and find that activity in populations of individual neurons in that region correlates with locomotion in trained mice. We expect that this paradigm will be a useful probe of information flow and network processing in brain-wide circuits involved in many sensory and cognitive processes. Copyright © 2016 the American Physiological Society.

  20. Large-scale genomics unveil polygenic architecture of human cortical surface area

    PubMed Central

    Chen, Chi-Hua; Peng, Qian; Schork, Andrew J.; Lo, Min-Tzu; Fan, Chun-Chieh; Wang, Yunpeng; Desikan, Rahul S.; Bettella, Francesco; Hagler, Donald J.; McCabe, Connor; Chang, Linda; Akshoomoff, Natacha; Newman, Erik; Ernst, Thomas; Van Zijl, Peter; Kuperman, Joshua; Murray, Sarah; Bloss, Cinnamon; Appelbaum, Mark; Gamst, Anthony; Thompson, Wesley; Bartsch, Hauke; Weiner, Michael; Aisen, Paul; Petersen, Ronald; Jack Jr, Clifford R.; Jagust, William; Trojanowki, John Q.; Toga, Arthur W.; Beckett, Laurel; Green, Robert C.; Saykin, Andrew J.; Morris, John; Shaw, Leslie M.; Khachaturian, Zaven; Sorensen, Greg; Carrillo, Maria; Kuller, Lew; Raichle, Marc; Paul, Steven; Davies, Peter; Fillit, Howard; Hefti, Franz; Holtzman, Davie; Mesulman, M. Marcel; Potter, William; Snyder, Peter J.; Schwartz, Adam; Montine, Tom; Thomas, Ronald G.; Donohue, Michael; Walter, Sarah; Gessert, Devon; Sather, Tamie; Jiminez, Gus; Harvey, Danielle; Bernstein, Matthew; Fox, Nick; Thompson, Paul; Schuff, Norbert; DeCarli, Charles; Borowski, Bret; Gunter, Jeff; Senjem, Matt; Vemuri, Prashanthi; Jones, David; Kantarci, Kejal; Ward, Chad; Koeppe, Robert A.; Foster, Norm; Reiman, Eric M.; Chen, Kewei; Mathis, Chet; Landau, Susan; Cairns, Nigel J.; Householder, Erin; Taylor-Reinwald, Lisa; Lee, Virginia M.Y.; Korecka, Magdalena; Figurski, Michal; Crawford, Karen; Neu, Scott; Foroud, Tatiana M.; Potkin, Steven; Shen, Li; Faber, Kelley; Kim, Sungeun; Nho, Kwangsik; Thal, Leon; Frank, Richard; Buckholtz, Neil; Albert, Marilyn; Hsiao, John; Westlye, Lars T.; Kremen, William S.; Jernigan, Terry L.; Hellard, Stephanie Le; Steen, Vidar M.; Espeseth, Thomas; Huentelman, Matt; Håberg, Asta K.; Agartz, Ingrid; Djurovic, Srdjan; Andreassen, Ole A.; Schork, Nicholas; Dale, Anders M.

    2015-01-01

    Little is known about how genetic variation contributes to neuroanatomical variability, and whether particular genomic regions comprising genes or evolutionarily conserved elements are enriched for effects that influence brain morphology. Here, we examine brain imaging and single-nucleotide polymorphisms (SNPs) data from ∼2,700 individuals. We show that a substantial proportion of variation in cortical surface area is explained by additive effects of SNPs dispersed throughout the genome, with a larger heritable effect for visual and auditory sensory and insular cortices (h2∼0.45). Genome-wide SNPs collectively account for, on average, about half of twin heritability across cortical regions (N=466 twins). We find enriched genetic effects in or near genes. We also observe that SNPs in evolutionarily more conserved regions contributed significantly to the heritability of cortical surface area, particularly, for medial and temporal cortical regions. SNPs in less conserved regions contributed more to occipital and dorsolateral prefrontal cortices. PMID:26189703

  1. Large-scale genomics unveil polygenic architecture of human cortical surface area.

    PubMed

    Chen, Chi-Hua; Peng, Qian; Schork, Andrew J; Lo, Min-Tzu; Fan, Chun-Chieh; Wang, Yunpeng; Desikan, Rahul S; Bettella, Francesco; Hagler, Donald J; Westlye, Lars T; Kremen, William S; Jernigan, Terry L; Le Hellard, Stephanie; Steen, Vidar M; Espeseth, Thomas; Huentelman, Matt; Håberg, Asta K; Agartz, Ingrid; Djurovic, Srdjan; Andreassen, Ole A; Schork, Nicholas; Dale, Anders M

    2015-07-20

    Little is known about how genetic variation contributes to neuroanatomical variability, and whether particular genomic regions comprising genes or evolutionarily conserved elements are enriched for effects that influence brain morphology. Here, we examine brain imaging and single-nucleotide polymorphisms (SNPs) data from ∼2,700 individuals. We show that a substantial proportion of variation in cortical surface area is explained by additive effects of SNPs dispersed throughout the genome, with a larger heritable effect for visual and auditory sensory and insular cortices (h(2)∼0.45). Genome-wide SNPs collectively account for, on average, about half of twin heritability across cortical regions (N=466 twins). We find enriched genetic effects in or near genes. We also observe that SNPs in evolutionarily more conserved regions contributed significantly to the heritability of cortical surface area, particularly, for medial and temporal cortical regions. SNPs in less conserved regions contributed more to occipital and dorsolateral prefrontal cortices.

  2. Estimation of neural dynamics from MEG/EEG cortical current density maps: application to the reconstruction of large-scale cortical synchrony.

    PubMed

    David, Olivier; Garnero, Line; Cosmelli, Diego; Varela, Francisco J

    2002-09-01

    There is a growing interest in elucidating the role of specific patterns of neural dynamics--such as transient synchronization between distant cell assemblies--in brain functions. Magnetoencephalography (MEG)/electroencephalography (EEG) recordings consist in the spatial integration of the activity from large and multiple remotely located populations of neurons. Massive diffusive effects and poor signal-to-noise ratio (SNR) preclude the proper estimation of indices related to cortical dynamics from nonaveraged MEG/EEG surface recordings. Source localization from MEG/EEG surface recordings with its excellent time resolution could contribute to a better understanding of the working brain. We propose a robust and original approach to the MEG/EEG distributed inverse problem to better estimate neural dynamics of cortical sources. For this, the surrogate data method is introduced in the MEG/EEG inverse problem framework. We apply this approach on nonaveraged data with poor SNR using the minimum norm estimator and find source localization results weakly sensitive to noise. Surrogates allow the reduction of the source space in order to reconstruct MEG/EEG data with reduced biases in both source localization and time-series dynamics. Monte Carlo simulations and results obtained from real MEG data indicate it is possible to estimate non invasively an important part of cortical source locations and dynamic and, therefore, to reveal brain functional networks.

  3. Large Root Cortical Cell Size Improves Drought Tolerance in Maize1[C][W][OPEN

    PubMed Central

    Chimungu, Joseph G.; Brown, Kathleen M.

    2014-01-01

    The objective of this study was to test the hypothesis that large cortical cell size (CCS) would improve drought tolerance by reducing root metabolic costs. Maize (Zea mays) lines contrasting in root CCS measured as cross-sectional area were grown under well-watered and water-stressed conditions in greenhouse mesocosms and in the field in the United States and Malawi. CCS varied among genotypes, ranging from 101 to 533 µm2. In mesocosms, large CCS reduced respiration per unit of root length by 59%. Under water stress in mesocosms, lines with large CCS had between 21% and 27% deeper rooting (depth above which 95% of total root length is located in the soil profile), 50% greater stomatal conductance, 59% greater leaf CO2 assimilation, and between 34% and 44% greater shoot biomass than lines with small CCS. Under water stress in the field, lines with large CCS had between 32% and 41% deeper rooting (depth above which 95% of total root length is located in the soil profile), 32% lighter stem water isotopic ratio of 18O to 16O signature, signifying deeper water capture, between 22% and 30% greater leaf relative water content, between 51% and 100% greater shoot biomass at flowering, and between 99% and 145% greater yield than lines with small cells. Our results are consistent with the hypothesis that large CCS improves drought tolerance by reducing the metabolic cost of soil exploration, enabling deeper soil exploration, greater water acquisition, and improved growth and yield under water stress. These results, coupled with the substantial genetic variation for CCS in diverse maize germplasm, suggest that CCS merits attention as a potential breeding target to improve the drought tolerance of maize and possibly other cereal crops. PMID:25293960

  4. Supratentorial Ependymoma: Disease Control, Complications, and Functional Outcomes After Irradiation

    SciTech Connect

    Landau, Efrat; Boop, Frederick A.; Conklin, Heather M.; Wu, Shengjie; Xiong, Xiaoping; Merchant, Thomas E.

    2013-03-15

    Purpose: Ependymoma is less commonly found in the supratentorial brain and has known clinical and molecular features that are unique. Our single-institution series provides valuable information about disease control for supratentorial ependymoma and the complications of supratentorial irradiation in children. Methods and Materials: A total of 50 children with newly diagnosed supratentorial ependymoma were treated with adjuvant radiation therapy (RT); conformal methods were used in 36 after 1996. The median age at RT was 6.5 years (range, 1-18.9 years). The entire group was characterized according to sex (girls 27), race (white 43), extent of resection (gross-total 46), and tumor grade (anaplastic 28). The conformal RT group was prospectively evaluated for neurologic, endocrine, and cognitive effects. Results: With a median follow-up time of 9.1 years from the start of RT for survivors (range, 0.2-23.2 years), the 10-year progression-free and overall survival were 73% + 7% and 76% + 6%, respectively. None of the evaluated factors was prognostic for disease control. Local and distant failures were evenly divided among the 16 patients who experienced progression. Eleven patients died of disease, and 1 of central nervous system necrosis. Seizure disorders were present in 17 patients, and 4 were considered to be clinically disabled. Clinically significant cognitive effects were limited to children with difficult-to-control seizures. The average values for intelligence quotient and academic achievement (reading, spelling, and math) were within the range of normal through 10 years of follow-up. Central hypothyroidism was the most commonly treated endocrinopathy. Conclusion: RT may be administered with acceptable risks for complications in children with supratentorial ependymoma. These results suggest that outcomes for these children are improving and that complications may be limited by use of focal irradiation methods.

  5. Neuroendocrine changes in patients with spontaneous supratentorial intracerebral hemorrhage.

    PubMed

    Huttner, Hagen B; Kiphuth, Ines-Christine; Teuber, Linda; Lücking, Hannes; Kloska, Stephan P; Staykov, Dimitre; Kuramatsu, Joji B; Mauer, Christoph; Breuer, Lorenz; Doerfler, Arnd; Köhrmann, Martin

    2013-02-01

    Neuroendocrine changes have been reported after ischemic stroke, subarachnoid hemorrhage, and brain trauma. As there are no corresponding data in patients with intracerebral hemorrhage (ICH) we analyzed various neuroendocrine parameters to investigate possible alterations in hormone profiles of patients with ICH. Twenty patients with ICH were prospectively enrolled in the study. Patients were a priori parted into two groups: Ten non-ventilated patients treated on the stroke-unit (hemorrhage volumes <20 ml, "small ICH"), and 10 ventilated patients treated on the neurocritical care unit (hematoma volumes >20 ml with possible additional ventricular involvement ("large ICH"). Neuroendocrine parameters were compared between both groups referring to reference values. The following parameters were obtained over a period of 9 days in 20 patients with spontaneous supratentorial ICH: thyrotropin, free thiiodothyronine and thyroxine, human growth hormone, insulin-like growth factor 1, luteinizing hormone, follicle-stimulating hormone, testosterone, prolactin, adrenocorticotropic hormone, and cortisol. Small ICH patients were in a median 71 (54-88) years old and had a mean ICH volume of 9.5 ± 6.5 ml, whereas large ICH patients were 65 (47-80) years old and showed a mean volume of 56 ± 30.2 ml. None of the patients revealed pathological alterations for thyrotropin, free thiiodothyronine, thyroxine, human growth hormone, insulin-like growth factor 1, and testosterone. There was only a mild decrease of adrenocorticotropic hormone and cortisol on day 3 in large ICH patients. Small ICH patients showed pathologically elevated levels of luteinizing and follicle-stimulating hormone throughout the observation period. Large ICH patients showed a marked increase of prolactin that developed during the course. Overall, neuroendocrine changes in ICH patients are not as profound as reported for ischemic stroke or subarachnoid hemorrhage. The clinical significance of increased LH and FSH

  6. Effect of supratentorial space-occupying lesions on regional intracranial pressure and local cerebral blood flow: an experimental study in baboons 1

    PubMed Central

    Symon, L.; Pasztor, E.; Branston, N. M.; Dorsch, N. W. C.

    1974-01-01

    Cortical blood flow and epidural intracranial pressure have been measured in the two supratentorial compartments of the intracranial space in experimental baboons during the acute expansion of a parieto-occipital epidural balloon. Differential pressures between the two halves of the supratentorial space have been found, and these have been associated with evidence that flow has fallen more quickly in the hemisphere most compressed. The evidence points to a more rapid exhaustion of the autoregulatory capacity in the hemisphere subjected to greater compression, a fall in perfusion pressure to below critical autoregulatory levels occurring slightly before that in the opposite hemisphere, and the establishment of a differential flow pattern for a short time during a critical phase of compression. The displacements induced by inflation of the parieto-occipital balloon have been described. Images PMID:4210683

  7. Supratentorial extraventricular WHO grade III (anaplastic) ependymoma 17 years after total removal of WHO grade II ependymoma of the fourth ventricle.

    PubMed

    Takeda, Naoya; Nishihara, Masamitsu; Harada, Tomoaki; Kidoguchi, Keiji; Hashimoto, Kimio

    2017-04-01

    We report a WHO grade III ependymoma of the supratentorial interhemispheric fissure and grew to form a large mass with anaplastic transformation without local recurrence 17 years after the total removal of a fourth ventricular WHO grade II ependymoma. We emphasize the necessity of long-term follow-up, even in benign ependymomas.

  8. CNTF-Treated Astrocyte Conditioned Medium Enhances Large-Conductance Calcium-Activated Potassium Channel Activity in Rat Cortical Neurons.

    PubMed

    Sun, Meiqun; Liu, Hongli; Xu, Huanbai; Wang, Hongtao; Wang, Xiaojing

    2016-08-01

    Seizure activity is linked to astrocyte activation as well as dysfunctional cortical neuron excitability produced from changes in calcium-activated potassium (KCa) channel function. Ciliary neurotrophic factor-treated astrocyte conditioned medium (CNTF-ACM) can be used to investigate the peripheral effects of activated astrocytes upon cortical neurons. However, CNTF-ACM's effect upon KCa channel activity in cultured cortical neurons has not yet been investigated. Whole-cell patch clamp recordings were performed in rat cortical neurons to evaluate CNTF-ACM's effects upon charybdotoxin-sensitive large-conductance KCa (BK) channel currents and apamin-sensitive small-conductance KCa (SK) channel current. Biotinylation and RT-PCR were applied to assess CNTF-ACM's effects upon the protein and mRNA expression, respectively, of the SK channel subunits SK2 and SK3 and the BK channel subunits BKα1 and BKβ3. An anti-fibroblast growth factor-2 (FGF-2) monoclonal neutralizing antibody was used to assess the effects of the FGF-2 component of CNTF-ACM. CNTF-ACM significantly increased KCa channel current density, which was predominantly attributable to gains in BK channel activity (p < 0.05). CNTF-ACM produced a significant increase in BKα1 and BKβ3 expression (p < 0.05) but had no significant effect upon SK2 or SK3 expression (p > 0.05). Blocking FGF-2 produced significant reductions in KCa channel current density (p > 0.05) as well as BKα1 and BKβ3 expression in CNTF-ACM-treated neurons (p > 0.05). CNTF-ACM significantly enhances BK channel activity in rat cortical neurons and that FGF-2 is partially responsible for these effects. CNTF-induced astrocyte activation results in secretion of neuroactive factors which may affect neuronal excitability and resultant seizure activity in mammalian cortical neurons.

  9. [Changes in the cytokine profile in patients with supratentorial meningiomas].

    PubMed

    Kislitsyn, Iu V; Belko, N S

    2013-01-01

    To evaluate prospects of immunocorrection in the treatment of patients with supratentorial meningiomas, we studied blood serum levels of interleukins 2, 4, 6, 10, 17, interferons α, Β, γ, heat shock proteins HSP60, HSP70 using ELISA. A study included 32 patients with supratentorial meningiomas in the presurgical period and a control group of 38 patients with lumbar disc hernias. We found the multidirectional changes in the cytokine profile that demonstrated the existence of immune imbalance in patients with meningiomas. There was the increase in the levels of Β-interferon, HSP60, interleukin 6 with the simultaneous decrease in α- and γ-interferons levels. The imbalance of cytokines in patients with meningiomas can have a negative impact on a clinical picture of the disease and worsen results of surgical treatment of tumors. To prevent secondary infectious complications after surgery, we recommend to administer glucocorticoids to decrease levels of interleukin 6 and α-interferon in the presurgical period.

  10. Dianhydrogalactitol and radiation therapy. Treatment of supratentorial glioma.

    PubMed

    Eagan, R T; Childs, D S; Layton, D D; Laws, E R; Bisel, H F; Holbrook, M A; Fleming, T R

    1979-05-11

    Dianhydrogalactitol was the most active of 177 agents tested against a mouse ependymoblastoma tumor. We conducted a prospectively randomized trial comparing whole-brain irradiation alone vs identical irradiation plus dianhydrogalactitol in 42 patients with grade 3 and 4 supratentorial astrocytomas. Patients receiving dianhydrogalactitol in addition to irradiation had a significantly longer median survival time (67 vs 35 weeks) than did patients receiving only irradiation. The major toxic effect of dianhydrogalactitol is hematologic suppression of a cumulative nature. Dianhydrogalactitol may play an important role (in conjunction with radiation therapy) in the initial treatment of patients with supratentorial glioma. Our data may indicate that the mouse ependymoblastoma system is a useful screen for agents to be used in the treatment of human glioma.

  11. Microsurgical anatomy of the supratentorial arachnoidal trabecular membranes and cisterns.

    PubMed

    Vinas, F C; Fandino, R; Dujovny, M; Chavez, V

    1994-12-01

    We examined the microsurgical anatomy of the supratentorial subarachnoid cisterns with a surgical microscope in 20 brains prepared using the immersion technique. The adult brains were immersed in Ringer's solution and air was injected into the subarachnoid cisterns while the brains remained submerged in solution. We identified nine trabecular membranes that limit the 15 cisterns. We specifically looked at the anatomical relationship between the supratentorial trabecular membranes and cisterns to their corresponding vessels and cranial nerves. The cistern divisions and the dispositions of trabecular membranes were closely related to the vascular division patterns of the principal brain arteries. A clear and thorough understanding of the neuroanatomical structures of the subarachnoid cisterns is important because they provide natural pathways to neurovascular and cranial nerve structures. These pathways allow access to intracranial arteries, veins, and nerves during microvascular procedures without disturbing surrounding important brain structures.

  12. Management of supratentorial cavernous malformations: craniotomy versus gammaknife radiosurgery.

    PubMed

    Shih, Yang-Hsin; Pan, David Hung-Chi

    2005-02-01

    Although craniotomy is the preferred treatment for symptomatic solitary supratentorial cavernous malformation (CM), radiosurgery is also an option. Our aim was to see which of these strategies was the most effective and under what circumstances. Of the 46 patients with solitary supratentorial CM that we retrospectively studied, 24 presented with seizures, 16 with focal neurological deficits due to intracerebral hemorrhage, and 6 with both seizures and bleeding. Sixteen were treated with craniotomy and 30 with gammaknife radiosurgery (GKRS). The main outcome measures for comparing craniotomy with GKRS were the proportion of postoperative seizure-free patients and the proportion of patients in whom no rebleeding occurred. Of patients presenting with seizures with/without bleeding, a significantly higher proportion of the craniotomy group than the GKRS group became and remained seizure-free (11/14 [79%] versus 4/16 [25%]; P < 0.002), and of those presenting with bleeding with/without seizures, a somewhat (though nonsignificantly) higher proportion did not rebleed (4/4 [100%] versus 12/18 [67%]) after surgery. The remaining 2 of the 16 craniotomy patients did not rebleed and had no residual tumor at follow up. Twelve of the 30 GKRS patients had evidence of tumor regression at follow up. In the clinical management of solitary supratentorial CM, craniotomy for lesionectomy resulted in better seizure control and rebleeding avoidance than GKRS.

  13. Resveratrol attenuates cortical neuron activity: roles of large conductance calcium-activated potassium channels and voltage-gated sodium channels.

    PubMed

    Wang, Ya-Jean; Chan, Ming-Huan; Chen, Linyi; Wu, Sheng-Nan; Chen, Hwei-Hisen

    2016-05-21

    Resveratrol, a phytoalexin found in grapes and red wine, exhibits diverse pharmacological activities. However, relatively little is known about whether resveratrol modulates the ion channels in cortical neurons. The large-conductance calcium-activated potassium channels (BKCa) and voltage-gated sodium channels were expressed in cortical neurons and play important roles in regulation of neuronal excitability. The present study aimed to determine the effects of resveratrol on BKCa currents and voltage-gated sodium currents in cortical neurons. Resveratrol concentration-dependently increased the current amplitude and the opening activity of BKCa channels, but suppressed the amplitude of voltage-gated sodium currents. Similar to the BKCa channel opener NS1619, resveratrol decreased the firing rate of action potentials. In addition, the enhancing effects of BKCa channel blockers tetraethylammonium (TEA) and paxilline on action potential firing were sensitive to resveratrol. Our results indicated that the attenuation of action potential firing rate by resveratrol might be mediated through opening the BKCa channels and closing the voltage-gated sodium channels. As BKCa channels and sodium channels are critical molecular determinants for seizure generation, our findings suggest that regulation of these two channels in cortical neurons probably makes a considerable contribution to the antiseizure activity of resveratrol.

  14. A large scale simulation of excitation propagation in layer 2/3 of primary and secondary visual cortices of mice.

    PubMed

    Ohtsu, Shoya; Nomura, Taishin; Uno, Shota; Maeda, Kazuki; Hayashida, Yuki; Yagi, Tetsuya

    2015-01-01

    Analyzing network architecture and spatio-temporal dynamics of the visual cortical areas can facilitate understanding visual information processing in the brain. Recently, several physiological experiments utilizing the fast in-vivo imaging technique have demonstrated that the primary visual cortex (V1) and the secondary visual cortex (V2) in mice exhibit complex properties of the responses to visual and electrical stimuli. In order to provide a tool for quantitatively analyzing such a complex dynamics of the cortices at the level of neurons and circuits, here, we constructed a physiologically plausible large-scale network model of the layers 2/3 of V1 and V2, composed of 14,056 multi-compartment neuron models. The Message-Passing-Interface-based parallel simulations of our network model were able to reproduce, at least quantitatively, the neural responses experimentally observed in mouse V1 and V2 with the voltage-sensitive dye imaging.

  15. Functional Outcome at 6 Months in Surgical Treatment of Spontaneous Supratentorial Intracerebral Haemorrhage

    PubMed Central

    Ghani, Abdul Rahman Izaini; John, John Tharakan Kalappurakkal; Idris, Zamzuri; Ghazali, Mazira Mohamad; Murshid, Nur-Leem; Musa, Kamarul Imran

    2008-01-01

    A prospective cohort study was done to evaluate the role of surgery in patients with spontaneous supratentorial intracerebral haemorrhage (SICH) and to identify predictors of outcome including the use of invasive regional cortical cerebral blood flow (rCoBF) and microdialysis. Surgery consisted of craniotomy or decompressive craniectomy. The ventriculostomy for intracranial pressure (ICP) monitoring and drainage and regional cortical cerebral blood flow (rCoBF) and microdialysis were performed in all subjects. Pre and post operative information on subjects were collected. The study end points was functional outcome at 6 months based on a dichotomised Glasgow Outcome Scale (GOS).The selected clinical, radiological, biochemical and treatment factors that may influence the functional outcome were analysed for their significance. A total of 36 patients were recruited with 27(75%) patients had Glasgow Coma Score (GCS) between 5 to 8 on admission and 9(25%) were admitted with GCS of 9. At 6 months, 86 % had a poor or unfavourable outcome (GOS I–III) and 14% had good or favourable outcome (GOS IV–V). The mortality rate at 6 months was 55%. Univariate analysis for the functional outcome identified 2 significant variables, the midline shift (p=0.013) and mean lactate:pyruvate ratio (p=0.038). Multivariate analysis identified midline shift as the single significant independent predictor of functional outcome (p=0.013).Despite aggressive regional cortical cerebral blood flow (rCoBF) and microdialysis study for detection of early ischemia, surgical treatment for spontaneous intracerebral haemorrhage only benefited a small number of patients in terms of favourable outcome (14%) and in the majority of patients (86%), the outcome was unfavourable. Patients with midline shift > 5mm has almost 21 times higher chances (adj) OR 20.8 of being associated with poor outcome (GOS I–III). PMID:22589638

  16. The Contribution of the Left Mid-fusiform Cortical Thickness to Chinese and English Reading in a Large Chinese Sample

    PubMed Central

    Zhang, Mingxia; Li, Jin; Chen, Chuansheng; Mei, Leilei; Xue, Gui; Lu, Zhonglin; Chen, Chunhui; He, Qinghua; Wei, Miao; Dong, Qi

    2012-01-01

    Previous functional neuroimaging studies have shown that the left mid-fusiform cortex plays a critical role in reading. However, there is very limited research relating this region’s anatomical structure to reading performance either in native or second language. Using structural MRI and three reading tasks (Chinese characters, English words, and alphabetic pseudowords) and a non-reading task (visual-auditory learning), this study investigated the contributions of the left mid-fusiform cortical thickness to reading in a large sample of 226 Chinese subjects. Results showed that cortical thickness in the left mid-fusiform gyrus was positively correlated with performance on all three reading tasks but not with the performance on the non-reading task. Our findings provide structural evidence for the left mid-fusiform cortex as the “gateway” region for reading Chinese and English. The absence of the association between the left mid-fusiform cortical thickness and non-reading performance implied the specific role of this area in reading skills, not in general language skills. PMID:23022094

  17. Large Scale Cortical Functional Networks Associated with Slow-Wave and Spindle-Burst-Related Spontaneous Activity

    PubMed Central

    McVea, David A.; Murphy, Timothy H.; Mohajerani, Majid H.

    2016-01-01

    Cortical sensory systems are active with rich patterns of activity during sleep and under light anesthesia. Remarkably, this activity shares many characteristics with those present when the awake brain responds to sensory stimuli. We review two specific forms of such activity: slow-wave activity (SWA) in the adult brain and spindle bursts in developing brain. SWA is composed of 0.5–4 Hz resting potential fluctuations. Although these fluctuations synchronize wide regions of cortex, recent large-scale imaging has shown spatial details of their distribution that reflect underlying cortical structural projections and networks. These networks are regulated, as prior awake experiences alter both the spatial and temporal features of SWA in subsequent sleep. Activity patterns of the immature brain, however, are very different from those of the adult. SWA is absent, and the dominant pattern is spindle bursts, intermittent high frequency oscillations superimposed on slower depolarizations within sensory cortices. These bursts are driven by intrinsic brain activity, which act to generate peripheral inputs, for example via limb twitches. They are present within developing sensory cortex before they are mature enough to exhibit directed movements and respond to external stimuli. Like in the adult, these patterns resemble those evoked by sensory stimulation when awake. It is suggested that spindle-burst activity is generated purposefully by the developing nervous system as a proxy for true external stimuli. While the sleep-related functions of both slow-wave and spindle-burst activity may not be entirely clear, they reflect robust regulated phenomena which can engage select wide-spread cortical circuits. These circuits are similar to those activated during sensory processing and volitional events. We highlight these two patterns of brain activity because both are prominent and well-studied forms of spontaneous activity that will yield valuable insights into brain function in

  18. Thalamic stimulation largely elicits orthodromic, rather than antidromic, cortical activation in an auditory thalamocortical slice.

    PubMed

    Rose, H J; Metherate, R

    2001-01-01

    Stimulation of the medial geniculate body in an auditory thalamocortical slice elicits a short-latency current sink in the middle cortical layers, as would be expected following activation of thalamocortical relay neurons. However, corticothalamic neurons can have axon collaterals that project to the middle layers, thus, a middle-layer current sink could also result from antidromic activation of corticothalamic neurons and their axon collaterals. The likelihood of thalamic stimulation activating corticothalamic neurons would be reduced substantially if the corticothalamic pathway was not well preserved in the slice, and/or if the threshold for antidromic activation was significantly higher than for orthodromic activation. To determine the prevalence and threshold of antidromic activation, we recorded intracellularly from day 14-17 mouse brain slices containing infragranular cortical neurons while stimulating the medial geniculate or thalamocortical pathway. Antidromic spikes were confirmed by spike collision and characterized according to spike latency "jitter" and the ability to follow a high-frequency (100 Hz) stimulus train. The ability to follow a 100-Hz tetanus was a reliable indicator of antidromic activation, but both antidromic and orthodromic spikes could have low jitter. Thalamic stimulation produced antidromic activation in two of 69 infragranular cortical neurons (<3%), indicating the presence of antidromic activity, but implying a limited corticothalamic connection in the slice. Antidromic spikes in 13 additional neurons were obtained by stimulating axons in the thalamocortical pathway. The antidromic threshold averaged 214+/-40.6 microA (range 6-475 microA), over seven times the orthodromic threshold for medial geniculate-evoked responses in layer IV extracellular (28+/-5.4 microA) or intracellular (27+/-5.6 microA) recordings. We conclude that medial geniculate stimulation activates relatively few corticothalamic neurons. Conversely, low

  19. Two-stage surgical resection of an atypical teratoid rhabdoid tumor occupying the infratentorial and supratentorial compartment in children under two years: Report of two cases

    PubMed Central

    Foreman, Paul M.; Madura, Casey J.; Johnston, James M.; Rocque, Brandon G.

    2016-01-01

    Introduction Atypical teratoid rhabdoid tumors are highly malignant neoplasms that present in young children and can grow to a large size. Maximal safe surgical resection is a mainstay of treatment. Presentation of cases Two cases of children under the age of two with large tumors involving the supratentorial and infratentorial compartments are presented. A two-staged operative approach combining a standard suboccipital approach to the fourth ventricle followed by an infratentorial, supracerebellar approach was utilized for resection. Discussion Maximal safe surgical resection of large tumors in young children is challenging. A staged approach is presented that affords maximal tumor resection while minimizing perioperative morbidity. Conclusion A staged operative approach appears safe and efficacious when resecting large tumors from both the infratentorial and supratentorial compartments in children less than two years of age. PMID:26812670

  20. Anesthetic actions of thiopental remain largely unaffected during cholinergic overstimulation in cultured cortical networks.

    PubMed

    Weimer, Isabel; Worek, Franz; Seeger, Thomas; Thiermann, Horst; Grasshoff, Christian; Antkowiak, Bernd; Balk, Monika

    2016-02-26

    In case of military or terrorist use of organophosphorus (OP) compounds victims are likely to suffer from not only intoxication but physical trauma as well. Appropriate emergency care may therefore include general anesthesia to allow life-saving surgical intervention. Since there is evidence that drug potency and efficacy of several anesthetics are attenuated by high concentrations of acetylcholine in the CNS, this study was designed to evaluate the anesthetic actions of thiopental during cholinergic overstimulation. Making use of organotypic slice cultures derived from the mouse neocortex, drug effects were assessed by extracellular voltage recordings of network activity at basal cholinergic tone and during simulated cholinergic crisis (high cholinergic tone). The latter was achieved by inhibition of acetylcholinesterases via soman and an ambient acetylcholine concentration of 10μM. The induction of cholinergic crisis in vitro increased the network activity of cortical neurons significantly. Surprisingly, differences in network activity between basal and high cholinergic tone became less pronounced with rising concentrations of thiopental and drug potency and efficacy were almost equivalent. These results clearly distinguish thiopental from previously tested general anesthetics and make it a promising candidate for in vivo studies to identify suitable anesthetics for victims of OP intoxication.

  1. Awake craniotomy for supratentorial gliomas: why, when and how?

    PubMed

    Ibrahim, George M; Bernstein, Mark

    2012-09-01

    Awake craniotomy has become an increasingly utilized procedure in the treatment of supratentorial intra-axial tumors. The popularity of this procedure is partially attributable to improvements in intraoperative technology and anesthetic techniques. The application of awake craniotomy to the field of neuro-oncology has decreased iatrogenic postoperative neurological deficits, allowed for safe maximal tumor resection and improved healthcare resource stewardship by permitting early patient discharge. In this article, we review recent evidence for the utility of awake craniotomy in the resection of gliomas and describe the senior author's experience in performing this procedure. Furthermore, we explore innovative applications of awake craniotomy to outpatient tumor resections and the conduct of neurosurgery in resource-poor settings. We conclude that awake craniotomy is an effective and versatile neurosurgical procedure with expanding applications in neuro-oncology.

  2. Supratentorial high convexity intradural extramedullary cavernous angioma: case report.

    PubMed

    Sakakibara, Yohtaro; Matsumori, Takashi; Taguchi, Yoshio; Koizumi, Hirotaka

    2010-01-01

    A 59-year-old man presented with a 2-month history of numbness in the lower left side of the face and upper left extremity. Axial T(1)-weighted magnetic resonance imaging showed a wedge-shaped mass measuring 3 x 2.5 cm in the right frontoparietal high convexity area that was heterogeneously enhanced after administration of gadolinium-diethylenetriaminepenta-acetic acid. Right frontoparietal craniotomy was performed and a bluish soft mass was found under the arachnoid membrane. The mass could be dissected free from the arachnoid membrane and the brain surface. Histological examination revealed the typical findings of cavernous angioma. Cavernous angioma should be considered in the differential diagnosis of supratentorial high convexity intradural extramedullary tumor, especially appearing as a heterogeneously enhanced mass adjacent to the brain parenchyma causing mass effect.

  3. Decompressive hemicraniectomy in supra-tentorial malignant infarcts

    PubMed Central

    Nizami, Furqan A.; Ramzan, Altaf U.; Wani, Abrar A.; Wani, Mushtaq A.; Malik, Nayil K.; Shah, Pervaiz A.; Asimi, Ravouf

    2012-01-01

    Background: Decompressive hemicraniectomy not only reduces the intracranial pressure but has been demonstrated to increase survival and decrease the morbidity in patients with supratentorial malignant brain infarcts (STMBI). The aim of this study was to assess the efficacy of surgical decompression to decrease the mortality and morbidity in patients with STMBI refractory to medical therapy and to compare the results with those of the medically managed patients. Methods: All the 24 consecutive patients with clinical and radiological diagnosis of STMBI, refractory to medical management in 2 years, were included. Option of surgical decompression after explaining the outcome, risk and benefits of the procedure was given to the attendants/relatives of all patients who were fulfilling the inclusion criteria. The patient group, whose attendants/relatives were not willing to undergo surgery, were subjected to the same medical therapy and they were taken as the “control group.” Results: Supratentorial malignant infarcts were more common in the age group of 41–60 years. Mean age of presentation was 42.16 ± 16.2 years and the mean GCS on admission was 7.83 ± 2.1. Mortality was 16.7% in the surgically and 25.0% in the medically managed group. Patients operated early (<48 h), age ≤60 years, midline shift <5 mm and size of infarct less than 2/3rd of the vascular territory involved showed good prognosis. The functional outcome revealed by modified Rankin Score (mRS) and Glasgow Outcome Score (GOS) was better in surgically managed patients. Results of the Zung Self-Rating Depression Score were better in surgically managed patients at 1 year. Barthal Index in the surgically managed group showed statistically significant results. Conclusions: Decompressive hemicraniectomy with duroplasty if performed early in STMBI not only decreases the mortality but also increases the functional outcome when compared with patients who were managed conservatively with medical therapy only

  4. Large-scale cortical networks estimated from scalp EEG signals during performance of goal-directed motor tasks.

    PubMed

    De Vico Fallani, F; Astolfi, L; Cincotti, F; Mattia, D; Maglione, A G; Vecchiato, G; Toppi, J; Della Penna, F; Salinari, S; Babiloni, F; Zouridakis, G

    2010-01-01

    The evaluation of the topological properties of brain networks is an emergent research topic, since the estimated cerebral connectivity patterns often have relatively large size and complex structure. Since a graph is a mathematical representation of a network, the use of a theoretical graph approach would describe concisely the topological features of the functional brain connectivity network estimated using neuroimaging techniques. In the present study, we analyze the changes in brain synchronization networks using high-resolution EEG signals obtained during performance of a complex goal-directed visuomotor task. Our results show that the cortical network is more stable when subjects reach the goal than when they fail by hitting an obstacle. These findings suggest the presence of a possible cerebral "marker" for motor actions that result in successful reaching of a target.

  5. Epileptogenicity of cavernomas depends on (archi-) cortical localization.

    PubMed

    Menzler, Katja; Chen, Xu; Thiel, Patricia; Iwinska-Zelder, Joanna; Miller, Dorothea; Reuss, Alexander; Hamer, Hajo M; Reis, Janine; Pagenstecher, Axel; Knake, Susanne; Bertalanffy, Helmut; Rosenow, Felix; Sure, Ulrich

    2010-10-01

    Patients with cerebral cavernomas have an estimated risk of the development of epilepsy of 1.5% to 2.4% per patient-year. To clarify the predictive value of different risk factors for epilepsy in patients with supratentorial cavernomas. We retrospectively analyzed data of 109 patients with supratentorial cavernomas. The correlation of epilepsy with the variables of single or multiple cavernomas, sex, age, side, cortical involvement, mesiotemporal archicortical vs neocortical involvement, lobar location of neocortical cavernomas, the presence of a hemosiderin rim and of edema, and the maximal diameters of cavernoma, hemosiderin rim, and edema, if present, were calculated using univariate and multivariate penalized likelihood logistic regression models. Cortical involvement was the most relevant risk factor for epilepsy (P < .0001). No patient with a subcortical cavernoma presented with epilepsy. Epilepsy was more common in patients with mesiotemporal archicortical cavernomas than in patients with neocortical cavernomas (P = .02), whereas the lobar location of neocortical cavernomas was not significantly associated with the risk of the development of epilepsy. In the multivariate analysis, a greater diameter of the cavernoma, the absence of edema, and localization in the left hemisphere were also associated with the occurrence of epilepsy (P < .05). The epileptogenicity of supratentorial cavernomas depends on cortical, especially mesiotemporal archicortical, involvement. Exclusively subcortical cavernomas are highly unlikely to cause epilepsy. This information is helpful in counseling patients with cavernomas regarding their risk of epileptic seizures and in patients with multiple cavernomas and epilepsy to generate a valid hypothesis of which cavernoma may cause epilepsy.

  6. Large-scale mapping of cortical synaptic projections with extracellular electrode arrays.

    PubMed

    Shein-Idelson, Mark; Pammer, Lorenz; Hemberger, Mike; Laurent, Gilles

    2017-09-01

    Understanding circuit computation in the nervous system requires sampling activity over large neural populations and maximizing the number of features that can be extracted. By combining planar arrays of extracellular electrodes with the three-layered cortex of turtles, we show that synaptic signals induced along individual axons as well as action potentials can be easily captured. Two types of information can be extracted from these signals, the neuronal subtype (inhibitory or excitatory)-whose identification is more reliable than with traditional measures such as action potential width-and a (partial) spatial map of functional axonal projections from individual neurons. Because our approach is algorithmic, it can be carried out in parallel on hundreds of simultaneously recorded neurons. Combining our approach with soma triangulation, we reveal an axonal projection bias among a population of pyramidal neurons in turtle cortex and confirm this bias through anatomical reconstructions.

  7. Large-Scale Mass Spectrometry Imaging Investigation of Consequences of Cortical Spreading Depression in a Transgenic Mouse Model of Migraine

    NASA Astrophysics Data System (ADS)

    Carreira, Ricardo J.; Shyti, Reinald; Balluff, Benjamin; Abdelmoula, Walid M.; van Heiningen, Sandra H.; van Zeijl, Rene J.; Dijkstra, Jouke; Ferrari, Michel D.; Tolner, Else A.; McDonnell, Liam A.; van den Maagdenberg, Arn M. J. M.

    2015-06-01

    Cortical spreading depression (CSD) is the electrophysiological correlate of migraine aura. Transgenic mice carrying the R192Q missense mutation in the Cacna1a gene, which in patients causes familial hemiplegic migraine type 1 (FHM1), exhibit increased propensity to CSD. Herein, mass spectrometry imaging (MSI) was applied for the first time to an animal cohort of transgenic and wild type mice to study the biomolecular changes following CSD in the brain. Ninety-six coronal brain sections from 32 mice were analyzed by MALDI-MSI. All MSI datasets were registered to the Allen Brain Atlas reference atlas of the mouse brain so that the molecular signatures of distinct brain regions could be compared. A number of metabolites and peptides showed substantial changes in the brain associated with CSD. Among those, different mass spectral features showed significant ( t-test, P < 0.05) changes in the cortex, 146 and 377 Da, and in the thalamus, 1820 and 1834 Da, of the CSD-affected hemisphere of FHM1 R192Q mice. Our findings reveal CSD- and genotype-specific molecular changes in the brain of FHM1 transgenic mice that may further our understanding about the role of CSD in migraine pathophysiology. The results also demonstrate the utility of aligning MSI datasets to a common reference atlas for large-scale MSI investigations.

  8. Exuberant cortical thymocyte proliferation mimicking T-lymphoblastic lymphoma within recurrent large inguinal lymph node masses of localized Castleman disease.

    PubMed

    Kansal, Rina; Nathwani, Bharat N; Yiakoumis, Xanthi; Moschogiannis, Maria; Sachanas, Sotirios; Stefanaki, Kalliopi; Pangalis, Gerassimos A

    2015-07-01

    We report a 13-year-old adolescent girl, the youngest thus far, with "an indolent T-lymphoblastic" proliferation (~10%) that uniquely presented within recurrent, large inguinal lymph node masses in a predominating (90%) background of Castleman disease. These nodal masses were resected thrice; the patient is well 5 years after diagnosis without further treatment. Histologically, the features of Castleman disease, hyaline vascular type, were present. Importantly, the interfollicular T-lymphoblastic component occurred as multiple clusters and islands of variable shapes and sizes composed of small "lymphoblasts" indistinguishable from normal cortical thymocytes but without thymic epithelial cells. Immunohistochemically, these lymphoblasts were consistent with the intermediate stage of T-cell differentiation (TdT(+)CD34(-)CD99(+)CD1a(+)CD2(+)CD3(+)CD4(+)CD8(+)CD5(+)CD7(+)CD10(+) [subset]), with 80% Ki-67. Molecularly, the T cells were nonclonal. Our case provides evidence for the benign nature of this highly unusual and poorly understood entity; because the current terminology can be readily misinterpreted as an indolent lymphoblastic lymphoma, we suggest a new term accurately reflecting this entity. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Cortical Thickness Abnormalities in Autism Spectrum Disorders Through Late Childhood, Adolescence, and Adulthood: A Large-Scale MRI Study.

    PubMed

    Khundrakpam, Budhachandra S; Lewis, John D; Kostopoulos, Penelope; Carbonell, Felix; Evans, Alan C

    2017-03-01

    Neuroimaging studies in autism spectrum disorders (ASDs) have provided inconsistent evidence of cortical abnormality. This is probably due to the small sample sizes used in most studies, and important differences in sample characteristics, particularly age, as well as to the heterogeneity of the disorder. To address these issues, we assessed abnormalities in ASD within the Autism Brain Imaging Data Exchange data set, which comprises data from approximately 1100 individuals (~6-55 years). A subset of these data that met stringent quality control and inclusion criteria (560 male subjects; 266 ASD; age = 6-35 years) were used to compute age-specific differences in cortical thickness in ASD and the relationship of any such differences to symptom severity of ASD. Our results show widespread increased cortical thickness in ASD, primarily left lateralized, from 6 years onwards, with differences diminishing during adulthood. The severity of symptoms related to social affect and communication correlated with these cortical abnormalities. These results are consistent with the conjecture that developmental patterns of cortical thickness abnormalities reflect delayed cortical maturation and highlight the dynamic nature of morphological abnormalities in ASD. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. Image-guided endoscopic surgery for spontaneous supratentorial intracerebral hematoma.

    PubMed

    Sun, Guo-Chen; Chen, Xiao-Lei; Hou, Yuan-Zheng; Yu, Xin-Guang; Ma, Xiao-Dong; Liu, Gang; Liu, Lei; Zhang, Jia-Shu; Tang, Hao; Zhu, Ru-Yuan; Zhou, Ding-Biao; Xu, Bai-Nan

    2017-09-01

    OBJECTIVE Endoscopic removal of intracerebral hematomas is becoming increasingly common, but there is no standard technique. The authors explored the use of a simple image-guided endoscopic method for removal of spontaneous supratentorial hematomas. METHODS Virtual reality technology based on a hospital picture archiving and communications systems (PACS) was used in 3D hematoma visualization and surgical planning. Augmented reality based on an Android smartphone app, Sina neurosurgical assist, allowed a projection of the hematoma to be seen on the patient's scalp to facilitate selection of the best trajectory to the center of the hematoma. A obturator and transparent sheath were used to establish a working channel, and an endoscope and a metal suction apparatus were used to remove the hematoma. RESULTS A total of 25 patients were included in the study, including 18 with putamen hemorrhages and 7 with lobar cerebral hemorrhages. Virtual reality combined with augmented reality helped in achieving the desired position with the obturator and sheath. The median time from the initial surgical incision to completion of closure was 50 minutes (range 40-70 minutes). The actual endoscopic operating time was 30 (range 15-50) minutes. The median blood loss was 80 (range 40-150) ml. No patient experienced postoperative rebleeding. The average hematoma evacuation rate was 97%. The mean (± SD) preoperative Glasgow Coma Scale (GCS) score was 6.7 ± 3.2; 1 week after hematoma evacuation the mean GCS score had improved to 11.9 ± 3.1 (p < 0.01). CONCLUSIONS Virtual reality using hospital PACS and augmented reality with a smartphone app helped precisely localize hematomas and plan the appropriate endoscopic approach. A transparent sheath helped establish a surgical channel, and an endoscope enabled observation of the hematoma's location to achieve satisfactory hematoma removal.

  11. Primary Posterior Fossa Lesions and Preserved Supratentorial Cerebral Blood Flow: Implications for Brain Death Determination.

    PubMed

    Varelas, Panayiotis N; Brady, Paul; Rehman, Mohammed; Afshinnik, Arash; Mehta, Chandan; Abdelhak, Tamer; Wijdicks, Eelco F

    2017-08-21

    Patients with primary posterior fossa catastrophic lesions may clinically meet brain death criteria, but may retain supratentorial brain function or blood flow. These patients could be declared brain-dead in the United Kingdom (UK), but not in the United States of America (USA). We report the outcome of adult patients with primary posterior fossa lesions without concurrent major supratentorial injury. Henry Ford Hospital database was reviewed over a period of 88 months in order to identify all adult patients with isolated brainstem or posterior fossa lesions. We excluded patients with concurrent significant supratentorial pathology potentially confounding the clinical brain death examination. One more patient from a different hospital meeting these criteria was also included. Three patients out of 161 met inclusion criteria (1.9% of all brain deaths during this period). With the addition of a fourth patient from another hospital, 4 patients were analyzed. All four patients had catastrophic brainstem and cerebellar injuries meeting the clinical criteria of brain death with positive apnea test in the UK. All had preserved supratentorial blood flow, which after a period of 2 h to 6 days disappeared on repeat testing, allowing declaration of brain death by US criteria in all four. One patient became an organ donor. Patients with primary posterior fossa catastrophic lesions, who clinically seem to be brain-dead, evolve from retaining to losing supratentorial blood flow. If absent cerebral blood flow is used as an additional criterion for the declaration of death by neurological criteria, these patients are not different than those who become brain death due to supratentorial lesions.

  12. [Factors significant for cerebral circulacion in patients with supratentorial brain tumors].

    PubMed

    Sboev, A Yu; Dolgih, V T; Larkin, V I

    2013-01-01

    Using the Doppler ultrasonography method the condition of brain blood circulation of 90 patients with supratentorial brain tumors (gliomas--43, meningiomas--34, metastasis--9) during pre-surgical period was studied. The factors changing brain blood circulation at patients with with supratentorial brain tumors were brain displacement, increase of intracranial pressure, histologic structure and the first symptoms duration of illness. Localization (for an exception of an occipital lobe) and the size of a tumor directly didn't render influence on blood circulation parameters.

  13. Adult supratentorial primitive neuroectodermal tumour presenting as intracranial haemorrhage: Case report.

    PubMed

    Black-Tiong, Sean P; Sandler, Simon J I; Otto, Sophia; Wells, Adam J

    2017-03-01

    Primitive neuroectodermal tumours (PNET) are highly malignant tumours with an aggressive clinical behaviour. Commonly seen in children, they are uncommon in the adult population, and rare in the supratentorial location. Adult supratentorial PNETs (ST-PNET) typically present with symptoms relating to raised intracranial pressure, seizures, or focal neurological deficits. Presentation with intracranial haemorrhage has been reported only twice before in the literature, one of which was fatal. We report the case of intracranial haemorrhage secondary to ST-PNET in a young adult and her immediate management.

  14. A comparison of two doses of mannitol on brain relaxation during supratentorial brain tumor craniotomy: a randomized trial.

    PubMed

    Quentin, Charlotte; Charbonneau, Sonia; Moumdjian, Robert; Lallo, Alexandre; Bouthilier, Alain; Fournier-Gosselin, Marie-Pierre; Bojanowski, Michel; Ruel, Monique; Sylvestre, Marie-Pierre; Girard, Francois

    2013-04-01

    Twenty percent mannitol is widely used to reduce brain bulk and facilitate the surgical approach in intracranial surgery. However, a dose-response relationship has not yet been established. In this study, we compared the effects of 0.7 and 1.4 g·kg(-1) mannitol on brain relaxation during elective supratentorial brain tumor surgery. In this prospective, randomized, double-blind study, we enrolled 80 patients undergoing supratentorial craniotomy for tumor resection. Patients were assigned to receive 0.7 g·kg(-1) (group L) or 1.4 g·kg(-1) (group H) of 20% mannitol at surgical incision. Brain relaxation was assessed immediately after opening of the dura on a scale ranging from 1 to 4 (1 = perfectly relaxed, 2 = satisfactorily relaxed, 3 = firm brain, 4 = bulging brain). There was no significant difference between the 2 groups regarding age, sex, body mass index, and brain tumor localization or size. In group L 52.5% of patients and in group H 77.5% of patients presented a midline shift (P = 0.03). The median scores of brain relaxation (interquantile range) were 2.0 (1.75-3) and 2.0 (1-3) (P = 0.16 for patients in group L and H, respectively). We then used a proportional odds model to adjust for this unbalanced distribution and to assess the group effect (low-dose versus high-dose mannitol) on brain relaxation scores. When adjusted for the presence of midline shift, the use of a higher dose of mannitol resulted in an odds ratio of 2.5 (P = 0.03). This indicates that, considering the effect of a midline shift, the odds of having a 1-level improvement in relaxation score in patients who received a higher dose of mannitol (group H) was 2.5 times as large as the odds for the low-dose group. The odds ratio of 0.29 (P = 0.007) for the midline shift indicates that its occurrence was associated with a higher probability of a lower relaxation score, on average. In this study, we show that 1.4 g·kg(-1) of 20% mannitol results in equivalent brain relaxation scores as 0.7 g

  15. Predictive value of median-SSEP in early phase of stroke: a comparison in supratentorial infarction and hemorrhage.

    PubMed

    Tzvetanov, Plamen; Rousseff, Rossen T

    2005-10-01

    To compare the prognostic value of median somatosensory evoked potentials (M-SSEP) changes in the early phase of supratentorial infarction and hemorrhage. This study includes 130 patients (mean age 62+/-11.4 years, 43 women, large middle cerebral artery territory infarction in 36 patients, restricted/lacunar in 55, massive supratentorial hemorrhage in 10, small/medium size hemorrhage in 31). M-SSEP were recorded early (0-7 days in ischemia, 0-21 days in hemorrhage) and patients stratified into groups with absent, abnormal, normal response. Clinical state was determined by the Medical Research Council (MRC) scale, Barthel Index and Rankin score and followed for at least 6 months. Moderate prognostic correlation was established between N20-P25 amplitudes (r=0.34, p<0.05) and N20-P25 amplitude ratio (r=0.45, p<0.01) and Barthel Index at 6 months in patients with ischemic stroke. Moderate relationship (r=-0.34, p<0.05) exists also between N20-P25 ratio and Rankin score at 6 months in patients with small/medium size hemorrhage. In large infarctions and small/medium size cerebral hemorrhages correlations with all clinical indices of outcome are weak. In massive hemorrhage, only a weak correlation (r=-0.19, p<0.05) between amplitude ratio and Rankin score was found. The combination of initial MRC and N20-P25 amplitude ratio has 10% (in hemorrhage) to 15% (in infarction) greater prognostic value (p<0.05) than initial alone. M-SSEP have independent predictive value regarding functional recovery in ischemic stroke and small/medium size cerebral hemorrhage. Combined assessment of initial MRC and M-SSEP substantially improves prognosis in acute stroke.

  16. Spontaneous supratentorial intracerebral hemorrhage: Does surgery benefit comatose patients?

    PubMed Central

    Yilmaz, Cem; Kabatas, Serdar; Gulsen, Salih; Cansever, Tufan; Gurkanlar, Doga; Caner, Hakan; Altinors, Nur

    2010-01-01

    Introduction: Treatment of spontaneous supratentorial intracerebral hemorrhage (SICH) is still controversial. We therefore analyzed the comatose patients diagnosed as having spontaneous SICH and treated by surgery. Materials and Methods: We retrospectively analyzed the collected data of 25 comatose patients with initial Glasgow Coma Scale (GCS) ≤ 8 diagnosed as having spontaneous SICH and they had been treated by surgical evacuation between 1996 and 2008. The outcome was assessed using Glasgow outcome scale (GOS). The side and location of the hematoma and ventricular extension of the hematoma were recorded. The hematoma volume was graded as mild (<30 cc), moderate (30–60 cc) and massive (>60 cc). Results: Age of the patients ranged from 25 to 78 years (mean: 59.6 ± 15.14 years). Among the 25 patients studied, 11 (44%) were females and 14 (56%) were males. GCS before surgery was <5 in 8 (32%) patients and between 5 and 8 in 17 (68%) patients. The hematoma volume was less than 30 cc in 2 patients, between 30 and 60 cc in 9 patients and more than 60 cc in 14 patients. Fourteen of the patients had no ventricular connection and 11 of the hematomas were connected to ventricle. All the 25 patients were treated with craniotomy and evacuation of the hematoma was done within an average of 2 hours on admission to the emergency department. Postoperatively, no rebleeding occurred in our patients. The most important complication was infection in 14 of the patients. The mortality of our surgical series was 56%. GCS before surgery was one of the strongest factors affecting outcome GCS (oGCS) (P = 0.017). Income GCS (iGCS), however, did not affect GOS (P = 0.64). The volume of the hematoma also affected the outcome (P = 0.037). Ventricular extension of the hematoma did affect the oGCS and GOS (P = 0.002), but not the iGCS of the patients (P = 0.139). Conclusion: Our data suggest that being surgically oriented is very important to achieve successful outcomes in a select group

  17. Subcortical and cortical gray matter atrophy in a large sample of patients with clinically isolated syndrome and early relapsing-remitting multiple sclerosis.

    PubMed

    Bergsland, N; Horakova, D; Dwyer, M G; Dolezal, O; Seidl, Z K; Vaneckova, M; Krasensky, J; Havrdova, E; Zivadinov, R

    2012-09-01

    Recent studies have shown that selective regional, but not global, GM atrophy occurs from clinical onset to conversion to clinically definite MS. Our aim was to investigate the difference in the extent of SDGM and cortical atrophy in a large sample of patients with CIS and early RRMS and to explore the relationship between SDGM and cortical atrophy and other MR imaging and clinical outcomes. Two hundred twelve patients with CIS recruited at the first clinical event (mean age, 29.3 years; median EDSS, 1.5; median disease duration, 3 months) and 177 patients with early RRMS (mean age, 30.7 years; median EDSS, 2.0; median disease duration, 47 months) were imaged on a 1.5T scanner by using a high-resolution 3D T1 spoiled gradient-recalled sequence. Volumetric data for SDGM structures were obtained by using FSL FIRST, while whole-brain, GM, white matter, cortical, and lateral ventricle volumes were estimated by using SIENAX software. Comparisons between the groups were adjusted for age and sex. Patients with early RRMS showed significantly lower SDGM but not cortical volumes compared with patients with CIS. The most apparent SDGM differences were evident in the caudate and thalamus (P < .0001), total SDGM (P = .0001), and globus pallidus (P = .01). Patients with CIS with a median T2 lesion volume >4.49 mL showed lower total SDGM, caudate, thalamus (P < .001), globus pallidus (P = .007), hippocampus (P = .004), and putamen (P = .01) volumes and higher lateral ventricle volume (P = .001) than those with a median T2 lesion volume <4.49 mL. Decreased thalamic volume showed the most consistent relationship with MR imaging outcomes (P < .0001) in patients with CIS. Significant SDGM, but not cortical, atrophy develops during the first 4 years of the RRMS. GM atrophy is relevant for disease progression from the earliest clinical stages.

  18. [Endoscopic fenestration of median supratentorial cerebrospinal fluid cysts].

    PubMed

    Melikian, A G; Ozerova, V I; Bragina, N N; Kolycheva, M V

    1999-01-01

    Mid-supratentorial liquor cysts are a relatively rare and generally congenital abnormality of the cerebral ventricles and subdural spaces. The data and views available in the literature on rational surgical policy is contradictory. The authors' experience in treating 16 patients was used to consider whether endoscopic techniques can be employed for invasive fenestration of the cysts. The goal of surgery was to remove the masses caused by cystic malformations and their local compression of the brain via fenestration of the walls of the cysts and via communication of their cavities with the ventricles and cisterns. There were solitary cysts in all cases (arachnoidal cysts of the interpedicular cistern and the third ventricle in 9; cysts of the ventricular septum in 4, ependicular cysts of the lateral ventricle in 2, and cysts of the celiac plexus of the third ventricle in other 2 cases, in 1 cases a liquor cyst was located in the midbrain thickness). The clinical picture was characterized by a combination of hypertensive, hydrocephalic and focal symptoms of damages to the hypothalamic and thalamic structures and the adjacent formations of the brain (pyramidal and extrapyramidal disorders, ataxia, chiasmal syndrome, metabolic and endocrine disorders, etc.). In 6 cases these symptoms were persistent despite preimplanted VP anastomosis. Rigid Storz endoscopes (Germany) with an external coat, 6 mm in diameter, and a Codman fibroendoscope (USA), 4 mm in diameter, were employed. Cystic ventriculostomy and cystic ventriculocisternostomies were made in 11 and 6 patients, respectively; one patient underwent endoscopic resection of the walls of an ependymal cyst. In one patient with signs of decreased liquor resorption, endoscopic fenestration was concurrently developed into a ventricle-peritoneal anastomosis. In other 4 anastomosis-dependent patients, the preimplanted mechanically consistent bypass system was left at its site. In 2 of these cases, cystic ventriculostomy was

  19. Minimally invasive surgery for spontaneous supratentorial intracerebral hemorrhage: a meta-analysis of randomized controlled trials.

    PubMed

    Zhou, Xinyu; Chen, Jianjun; Li, Qi; Ren, Gaoping; Yao, Guoen; Liu, Ming; Dong, Qiang; Guo, Jìng; Li, Leilei; Guo, Jing; Xie, Peng

    2012-11-01

    There has been a nonstandard surgical procedure and extensive international controversy in minimally invasive surgery (MIS) for the management of spontaneous supratentorial intracerebral hemorrhage. This meta-analysis assessed the effectiveness of MIS as compared with other treatment options, including conservative medical treatment and conventional craniotomy, in patients with supratentorial intracerebral hemorrhage. PubMed, Embase, Cochrane Controlled Trials Register (CCTR), Web of Science, European Association for Grey Literature Exploitation (EAGLE), National Technical Information Service (NTIS), Current Controlled Trials, Clinical Trials, International Clinical Trials Registry, Internet Stroke Center, Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI) (last searched December 2011) were searched. Randomized controlled trials on MIS in patients with computed tomography-confirmed supratentorial intracerebral hemorrhage were included. We excluded low-quality randomized controlled trials. The death or dependence at the end of follow-up was defined as the primary outcome, and the death at the end of follow-up was defined as the secondary outcome. The 313 randomized controlled trials met the included criteria. We only analyzed 12 high-quality randomized controlled trials involving 1955 patients. The quality of the included trials was consistently high. OR of the primary outcome and secondary outcome of MIS both showed significant reductions (OR, 0.54, P<0.00001; OR, 0.53, P<0.00001). Patients with supratentorial intracerebral hemorrhage may benefit more from MIS than other treatment options. The most likely candidates to benefit from MIS are both sexes, age of 30 to 80 years with superficial hematoma, Glasgow Coma Scale score of ≥9, hematoma volume between 25 and 40 mL, and within 72 hours after onset of symptoms. Our study could help select appropriate patients for MIS and guide clinicians to optimize treatment

  20. Laser speckle contrast imaging reveals large-scale synchronization of cortical autoregulation dynamics influenced by nitric oxide.

    PubMed

    Mitrou, Nicholas; Scully, Christopher G; Braam, Branko; Chon, Ki H; Cupples, William A

    2015-04-01

    Synchronization of tubuloglomerular feedback (TGF) dynamics in nephrons that share a cortical radial artery is well known. It is less clear whether synchronization extends beyond a single cortical radial artery or whether it extends to the myogenic response (MR). We used LSCI to examine cortical perfusion dynamics in isoflurane-anesthetized, male Long-Evans rats. Inhibition of nitric oxide synthases by N(ω)-nitro-l-arginine methyl ester (l-NAME) was used to alter perfusion dynamics. Phase coherence (PC) was determined between all possible pixel pairs in either the MR or TGF band (0.09-0.3 and 0.015-0.06 Hz, respectively). The field of view (≈4 × 5 mm) was segmented into synchronized clusters based on mutual PC. During the control period, the field of view was often contained within one cluster for both MR and TGF. PC was moderate for TGF and modest for MR, although significant in both. In both MR and TGF, PC exhibited little spatial variation. After l-NAME, the number of clusters increased in both MR and TGF. MR clusters became more strongly synchronized while TGF clusters showed small highly coupled, high-PC regions that were coupled with low PC to the remainder of the cluster. Graph theory analysis probed modularity of synchronization. It confirmed weak synchronization of MR during control that probably was not physiologically relevant. It confirmed extensive and long-distance synchronization of TGF during control and showed increased modularity, albeit with larger modules seen in MR than in TGF after l-NAME. The results show widespread synchronization of MR and TGF that is differentially affected by nitric oxide. Copyright © 2015 the American Physiological Society.

  1. Three-dimensional visualization with large data sets: a simulation of spreading cortical depression in human brain.

    PubMed

    Ertürk, Korhan Levent; Şengül, Gökhan

    2012-01-01

    We developed 3D simulation software of human organs/tissues; we developed a database to store the related data, a data management system to manage the created data, and a metadata system for the management of data. This approach provides two benefits: first of all the developed system does not require to keep the patient's/subject's medical images on the system, providing less memory usage. Besides the system also provides 3D simulation and modification options, which will help clinicians to use necessary tools for visualization and modification operations. The developed system is tested in a case study, in which a 3D human brain model is created and simulated from 2D MRI images of a human brain, and we extended the 3D model to include the spreading cortical depression (SCD) wave front, which is an electrical phoneme that is believed to cause the migraine.

  2. Predictors of seizure freedom in the surgical treatment of supratentorial cavernous malformations.

    PubMed

    Englot, Dario J; Han, Seunggu J; Lawton, Michael T; Chang, Edward F

    2011-12-01

    Seizures are the most common presenting symptom of supratentorial cerebral cavernous malformations (CCMs) and progress to medically refractory epilepsy in 40% of patients. Predictors of seizure freedom in the resection of CCMs are incompletely understood. The authors systematically reviewed the published literature on seizure freedom following the resection of supratentorial CCMs in patients presenting with seizures. Seizure outcomes were stratified across 12 potential prognostic variables. A total of 1226 patients with supratentorial CCMs causing seizures were identified across 31 predominantly retrospective studies; 361 patients had medically refractory epilepsy. Seventy-five percent of the patients were seizure free after microsurgical lesion removal, whereas 25% continued to have seizures. All patients had had preoperative seizures and > 6 months of postoperative follow-up. Modifiable predictors of postoperative seizure freedom included gross-total resection (OR 36.6, 95% CI 8.5-157.5) and surgery within 1 year of symptom onset (OR 1.83, 95% CI 1.30-2.58). Additional prognostic indicators of a favorable outcome were a CCM size < 1.5 cm (OR 15.4, 95% CI 5.2-45.4), the absence of multiple CCMs (OR 2.02, 95% CI 1.13-3.60), medically controlled seizures (OR 2.38, 95% CI 1.29-4.39), and the lack of secondarily generalized seizures (OR 3.33, 95% CI 2.09-5.30). Other factors, including extended resection of the hemosiderin ring, were not significantly predictive. In the surgical treatment of supratentorial CCMs, gross-total resection and early operative intervention may improve seizure outcome. While surgery should not be considered the first-line treatment for CCM-related epilepsy, it is important to understand the variables associated with seizure freedom in CCM resection given the considerable morbidity and diminished quality of life associated with epilepsy.

  3. Conventional and advanced MRI features of pediatric intracranial tumors: supratentorial tumors.

    PubMed

    Borja, Maria J; Plaza, Michael J; Altman, Nolan; Saigal, Gaurav

    2013-05-01

    OBJECTIVE. Our objective is to review the imaging characteristics and applications of conventional and advanced neuroimaging techniques of supratentorial intracranial masses in the pediatric population. Specifically, we review astrocytomas, oligodendrogliomas, primary neuroectodermal tumors, dysembryoplastic neuroepithelial tumors, gangliogliomas, arachnoid cysts, and choroid plexus and pineal region masses. CONCLUSION. Advanced imaging methods, such as MR spectroscopy, perfusion MRI, functional MRI, diffusion-tensor imaging, and tractography, help develop a more accurate differential diagnosis and aid in planning tumor treatment.

  4. Coexistent Supratentorial and Infratentorial Subdural Hygromas with Hydrocephalus After Chiari Decompression Surgery: Review of Literature.

    PubMed

    Prasad, G Lakshmi; Menon, Girish R

    2016-09-01

    Foramen magnum decompression (FMD) is the standard procedure for Chiari I malformation. Although seemingly a straightforward procedure, recent articles have reported an increase in various complications. We describe a rare complication of coexistent supratentorial and infratentorial subdural hygromas (SDHs) with hydrocephalus noted after FMD and provide a detailed review of the literature on this topic. A 34-year-old woman presented with strain-related suboccipital headache and myelopathy for 6 months. Imaging revealed tonsillar herniation up to C2 level and cervical syringomyelia. A standard FMD, C1 posterior arch removal, and tonsillar reduction was performed. After an initial uneventful postoperative course, she had 2 readmissions with headache, vomiting, and ataxia. Imaging showed a tense pseudomeningocele and concomitant supratentorial and infratentorial (initially right-sided, followed by left-sided) SDHs with ventriculomegaly. She was conservatively managed with antiedema measures and had excellent relief of symptoms. For the literature review, only cases with concomitant supratentorial and infratentorial SDHs with hydrocephalus were searched online and analyzed. Including ours, 10 cases have been reported. Mean age was 25.3 years. The male-to-female ratio was 1:2.3. Symptoms appeared an average of 12.6 days postoperatively. Treatment was with conservative management in 3 cases, and 3 cases required permanent cerebrospinal fluid diversions. Mean follow-up duration was 9.4 months (range, 1-27 months). Coexistent supratentorial and infratentorial SDHs with hydrocephalus after Chiari decompression is a very rare occurrence. Treatment needs to be individualized based on the predominant symptomatic lesion, and surgical options need to be judiciously considered. Good prognosis is the rule in most cases. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Brainstem injury associated with supratentorial lesions is revealed by electronystagmography of the cold caloric reflex test

    PubMed Central

    Fu, Qizhi; Qi, Zhiguo; Yang, Ruirui; Cheng, Ke; Yang, Yongtao; Xie, Peng

    2017-01-01

    To explore the brainstem injury associated with supratentorial lesions, we conducted analysis of ICP levels and detected ENG parameters by using the cold caloric reflex test and histopathological examinations of the brainstem. Rat model of intracerebral hemorrhage was well-established in the study of supratentorial lesions of varying severities (n=210). Intracerebral pressure monitoring and electronystagmography of the cold caloric reflex test were simultaneously performed in animals. Apoptotic, immunohistochemical, and histopathological changes in different segments of the brainstem were investigated at various time intervals. Electronystagmography parameters were analyzed by cold caloric reflex test. The result showed that the increase of intracerebral pressure was correlated with lesion severity including elevating levels and rostral-caudal progression of neuronal apoptosis, demyelination, N-methyl-D-aspartate cell receptor down-regulation (r=0.815), and histopathological changes. Mutiple discrimination analysis of electronystagmography parameters presented a diagnostic accuracy rate of 79.5% in localizing brainstem injury. In conclusion, our data demonstrated that electronystagmography monitoring along with the cold caloric reflex test performed a favorable effect on the estimation of brainstem injury in ICH rat model, which provided a potential bedside diagnostic tool to assess and predict the progress of supratentorial lesion patient in future. PMID:28559965

  6. Seizure outcome after resection of supratentorial cavernous malformations: a study of 168 patients.

    PubMed

    Baumann, Christian R; Acciarri, Nicola; Bertalanffy, Helmut; Devinsky, Orrin; Elger, Christian E; Lo Russo, Giorgio; Cossu, Massimo; Sure, Uli; Singh, Anuradha; Stefan, Hermann; Hammen, Tilo; Georgiadis, Dimitrios; Baumgartner, Ralf W; Andermann, Frederick; Siegel, Adrian M

    2007-03-01

    The optimal management of cerebral cavernous malformations (CCMs) with epileptic seizures is still a matter of debate. The aim of our study was to examine seizure outcome in the largest published series of surgically treated patients with epilepsy due to a supratentorial CCM, and to define predictors for good surgical outcome. We retrospectively studied 168 consecutive patients with a single supratentorial CCM and symptomatic epilepsy in a multicenter study. Pre- and postoperative clinical examinations, age at epilepsy onset, age at operation, type of symptoms due to the CCM (seizures, headache, hemorrhage, focal deficits), type and frequency of epileptic seizures, and the localization and size of the CCM were assessed. Seizure outcome was determined in the first, second, and third postoperative years. The CCM was completely resected in all patients. More than two thirds of the patients were classified as seizure free in the first 3 postoperative years. Predictors for good seizure outcome were age older than 30 years at the time of surgery, mesiotemporal CCM localization, CCM size <1.5 cm, and the absence of secondarily generalized seizures. No mortality occurred in our series, but only mild postoperative neurologic deficits in 12 (7%) patients. Considering the natural history of CCMs, the favorable neurologic and seizure outcome, surgical resection of CCMs should be considered in all patients with supratentorial CCMs and concomitant epilepsy, irrespective of the presence or absence of predictors for a favorable seizure outcome.

  7. A Smartphone App to Assist Scalp Localization of Superficial Supratentorial Lesions--Technical Note.

    PubMed

    Eftekhar, Behzad

    2016-01-01

    Neuronavigation is an established technology in neurosurgery. In parts of the world and certain circumstances in which neuronavigation is not easily available or affordable, alternative techniques may be considered. An app to assist scalp localization of superficial supratentorial lesions has been introduced, and its accuracy has been compared with established neuronavigation systems. Sina is a simple smartphone app that overlaps the transparent patients' computed tomography/magnetic resonance images on the background camera. How to use Sina intraoperatively is described. The app was used for scalp localization of the center of the lesions in 11 patients with supratentorial pathologies <3 cm in longest diameter and <2 cm from the cortex. After localization of the lesion using Sina, the center of the lesion was marked on the scalp using standard neuronavigation systems and the deviations were measured. Implementation of Sina for intraoperative scalp localization is simple and practical. The center of the lesions localized by Sina was 10.2 ± 2 mm different from localization done by standard neuronavigation systems. When neuronavigation is not easily available or affordable, Sina can be helpful for scalp localization and preoperative planning of the incision for selected supratentorial pathologies. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    PubMed Central

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1–10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications. PMID:26782020

  9. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects.

    PubMed

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-19

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  10. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    NASA Astrophysics Data System (ADS)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  11. Supratentorial ependymoma with glial component of two different histologies and neuropil-like islands: a case report.

    PubMed

    Ahn, Soomin; Kang, So Young; Suh, Yeon-Lim

    2014-01-01

    Glioneuronal tumors with neuropil-like islands (GTNIs) are a basically infiltrating astrocytoma or mixed oligoastrocytoma, containing large neuropil-like islands (NIs). Recently, we experienced a peculiar case of supratentorial ependymoma with NIs. A 29-month-old girl presented with seizure and a brain magnetic resonance image revealed a huge heterogeneous mass in the left lateral ventricle. Histologically, glial components of the tumor showed two different histologies: anaplastic ependymoma and myxopapillary ependymomatous features. The latter was admixed with numerous NIs. Immunohistochemically, the glial components expressed GFAP and a paranuclear dot pattern of EMA and CD99, whereas the NIs were positive for synaptophysin and MAP2. KI-67 was high in the anaplastic ependymoma, but very low in the fascicles of spindle cells and NIs. Quantitative PCR confirmed mRNA expression of five genes related to neuronal differentiation in both the glial and neuronal components of this tumor. Our case suggests that ependymoma with NIs may be in a spectrum of GTNIs.

  12. [Method of superimposing the angiographically located supratentorial lesion on the scalp prior to craniotomy].

    PubMed

    Miyazaki, Y

    1976-07-01

    One of the important points in operation of the intracranial supratentorial lesion is appropriate site and size of bony window made by craniotomy and this matter is also important first step in procedure of craniotomy. On the other hand, the site and size of bony window made in craniotomy for supratentorial lesion has relationship with perfectibility of operation. The detail intracranial situation and extent of supratentorial lesion is decided from the datas of various examinations and the findings in cerebral angiogram give a most important and valuable information to the neurosurgeon at present. The neurosurgeons used to decide the area of craniotomy from the findings of cerebral angiogram but there are some difficulty in transfer of findings related with situation of supratentorial lesion in angiogram to the patient's scalp, because the film of cerebral angiography is a projected picture of spheric head by X-ray to the plane. The author devised the planning method of site and size of bony window in craniotomy by transfer the location and extent of supratentorial lesion in cerebral angiogram to the patient's scalp and the author have been recognized for the past five years that this method is simple one and has clinical accuracy. The principle of the author's method are as follows. The film of cerebral angiography in lateral projection and the patient's scalp are divided into nine parts by same manner and the relation of the site and extent of lesion in cerebral angiogram with divided parts transfer to the division of the patient's scalp under special care to make minimize errors due to use the cerebral angiogram which is picture made by projection in a plane from spheric intracranial supratentorial space. Five points and seven lines are used to divide the film of cerebral angiography and the patient's scalp. Five divide points are most upper part of margin of external acoustic meatus, most posterior edge of auricle, upper, lower and lateral edge of orbit. The

  13. Large Amplitude Cortical Evoked Potentials in Nonepileptic Patients. Reviving an Old Neurophysiologic Tool to Help Detect CNS Pathology.

    PubMed

    Martín-Palomeque, Guillermo; Castro-Ortiz, Antonio; Pamplona-Valenzuela, Pilar; Saiz-Sepúlveda, Miguel Á; Cabañes-Martínez, Lidia; López, Jaime R

    2017-01-01

    Although large amplitude evoked potentials (EPs) are typically associated with progressive myoclonic epilepsy patients, giant EPs imply central nervous system (CNS) hyperexcitability and can be seen in various nonepileptic disorders. We performed a retrospective chart review including history, physical examination, imaging and diagnostic studies of nonepileptic patients with large amplitude somatosensory evoked potentials (SSEPs) and visual evoked potentials (VEPs) during 2007 to 2013. Large amplitude EPs were defined as follows: VEPs (N75-P100) >18 μV; and SSEPs (N20-P25) >6.4 μV. Recording montage for VEPs was Oz-Cz and SSEPs C3'/C4'-Fz. Fifty-two patients (33 females, 19 males; age range, 9-90 years) were identified. No CNS pathology was detected in 7 patients. All remaining patients were diagnosed with new CNS disorders including: vascular (37%); myelopathies (13%); demyelinating (11%); space occupying lesions (8.7%); syringomyelia (8.7%); hydrocephalus (6.5%); Vitamin B-12 deficiency (4.3%); multiple system atrophy (4.3%); and toxins (2.2%). This study supports the notion that large amplitude EP implies CNS hyperexcitability and CNS disease. These results confirm the utility of EP studies in patients with suspected CNS pathology.

  14. Seizures in supratentorial meningioma: a systematic review and meta-analysis.

    PubMed

    Englot, Dario J; Magill, Stephen T; Han, Seunggu J; Chang, Edward F; Berger, Mitchel S; McDermott, Michael W

    2016-06-01

    OBJECT Meningioma is the most common benign intracranial tumor, and patients with supratentorial meningioma frequently suffer from seizures. The rates and predictors of seizures in patients with meningioma have been significantly under-studied, even in comparison with other brain tumor types. Improved strategies for the prediction, treatment, and prevention of seizures in patients with meningioma is an important goal, because tumor-related epilepsy significantly impacts patient quality of life. METHODS The authors performed a systematic review of PubMed for manuscripts published between January 1980 and September 2014, examining rates of pre- and postoperative seizures in supratentorial meningioma, and evaluating potential predictors of seizures with separate meta-analyses. RESULTS The authors identified 39 observational case series for inclusion in the study, but no controlled trials. Preoperative seizures were observed in 29.2% of 4709 patients with supratentorial meningioma, and were significantly predicted by male sex (OR 1.74, 95% CI 1.30-2.34); an absence of headache (OR 1.77, 95% CI 1.04-3.25); peritumoral edema (OR 7.48, 95% CI 6.13-9.47); and non-skull base location (OR 1.77, 95% CI 1.04-3.25). After surgery, seizure freedom was achieved in 69.3% of 703 patients with preoperative epilepsy, and was more than twice as likely in those without peritumoral edema, although an insufficient number of studies were available for formal meta-analysis of this association. Of 1085 individuals without preoperative epilepsy who underwent resection, new postoperative seizures were seen in 12.3% of patients. No difference in the rate of new postoperative seizures was observed with or without perioperative prophylactic anticonvulsants. CONCLUSIONS Seizures are common in supratentorial meningioma, particularly in tumors associated with brain edema, and seizure freedom is a critical treatment goal. Favorable seizure control can be achieved with resection, but evidence does

  15. Effectiveness of endoscopic surgery for supratentorial hypertensive intracerebral hemorrhage: a comparison with craniotomy.

    PubMed

    Xu, Xinghua; Chen, Xiaolei; Li, Fangye; Zheng, Xuan; Wang, Qun; Sun, Guochen; Zhang, Jun; Xu, Bainan

    2017-04-07

    OBJECTIVE The goal of this study was to investigate the effectiveness and practicality of endoscopic surgery for treatment of supratentorial hypertensive intracerebral hemorrhage (HICH) compared with traditional craniotomy. METHODS The authors retrospectively analyzed 151 consecutive patients who were operated on for treatment of supratentorial HICH between January 2009 and June 2014 in the Department of Neurosurgery at Chinese PLA General Hospital. Patients were separated into an endoscopy group (82 cases) and a craniotomy group (69 cases), depending on the surgery they received. The hematoma evacuation rate was calculated using 3D Slicer software to measure the hematoma volume. Comparisons of operative time, intraoperative blood loss, Glasgow Coma Scale score 1 week after surgery, hospitalization time, and modified Rankin Scale score 6 months after surgery were also made between these groups. RESULTS There was no statistically significant difference in preoperative data between the endoscopy group and the craniotomy group (p > 0.05). The hematoma evacuation rate was 90.5% ± 6.5% in the endoscopy group and 82.3% ± 8.6% in the craniotomy group, which was statistically significant (p < 0.01). The operative time was 1.6 ± 0.7 hours in the endoscopy group and 5.2 ± 1.8 hours in the craniotomy group (p < 0.01). The intraoperative blood loss was 91.4 ± 93.1 ml in the endoscopy group and 605.6 ± 602.3 ml in the craniotomy group (p < 0.01). The 1-week postoperative Glasgow Coma Scale score was 11.5 ± 2.9 in the endoscopy group and 8.3 ± 3.8 in the craniotomy group (p < 0.01). The hospital stay was 11.6 ± 6.9 days in the endoscopy group and 13.2 ± 7.9 days in the craniotomy group (p < 0.05). The mean modified Rankin Scale score 6 months after surgery was 3.2 ± 1.5 in the endoscopy group and 4.1 ± 1.9 in the craniotomy group (p < 0.01). Patients had better recovery in the endoscopy group than in the craniotomy group. Data are expressed as the mean ± SD

  16. Seizures in supratentorial meningioma: a systematic review and meta-analysis

    PubMed Central

    Englot, Dario J.; Magill, Stephen T.; Han, Seunggu J.; Chang, Edward F.; Berger, Mitchel S.; McDermott, Michael W.

    2016-01-01

    Object Meningioma is the most common benign intracranial tumor, and patients with supratentorial meningioma frequently suffer from seizures. The rates and predictors of seizures in patients with meningioma have been significantly under-studied, even in comparison with other brain tumor types. Improved strategies for the prediction, treatment, and prevention of seizures in patients with meningioma is an important goal, because tumor-related epilepsy significantly impacts patient quality of life. Methods The authors performed a systematic review of PubMed for manuscripts published between January 1980 and September 2014, examining rates of pre- and postoperative seizures in supratentorial meningioma, and evaluating potential predictors of seizures with separate meta-analyses. Results The authors identified 39 observational case series for inclusion in the study, but no controlled trials. Preoperative seizures were observed in 29.2% of 4709 patients with supratentorial meningioma, and were significantly predicted by male sex (OR 1.74, 95% CI 1.30–2.34); an absence of headache (OR 1.77, 95% CI 1.04–3.25); peritumoral edema (OR 7.48, 95% CI 6.13–9.47); and non–skull base location (OR 1.77, 95% CI 1.04–3.25). After surgery, seizure freedom was achieved in 69.3% of 703 patients with preoperative epilepsy, and was more than twice as likely in those without peritumoral edema, although an insufficient number of studies were available for formal meta-analysis of this association. Of 1085 individuals without preoperative epilepsy who underwent resection, new postoperative seizures were seen in 12.3% of patients. No difference in the rate of new postoperative seizures was observed with or without perioperative prophylactic anticonvulsants. Conclusions Seizures are common in supratentorial meningioma, particularly in tumors associated with brain edema, and seizure freedom is a critical treatment goal. Favorable seizure control can be achieved with resection, but

  17. Neonatal L-glutamine modulates anxiety-like behavior, cortical spreading depression, and microglial immunoreactivity: analysis in developing rats suckled on normal size- and large size litters.

    PubMed

    de Lima, Denise Sandrelly Cavalcanti; Francisco, Elian da Silva; Lima, Cássia Borges; Guedes, Rubem Carlos Araújo

    2017-02-01

    In mammals, L-glutamine (Gln) can alter the glutamate-Gln cycle and consequently brain excitability. Here, we investigated in developing rats the effect of treatment with different doses of Gln on anxiety-like behavior, cortical spreading depression (CSD), and microglial activation expressed as Iba1-immunoreactivity. Wistar rats were suckled in litters with 9 and 15 pups (groups L 9 and L 15; respectively, normal size- and large size litters). From postnatal days (P) 7-27, the animals received Gln per gavage (250, 500 or 750 mg/kg/day), or vehicle (water), or no treatment (naive). At P28 and P30, we tested the animals, respectively, in the elevated plus maze and open field. At P30-35, we measured CSD parameters (velocity of propagation, amplitude, and duration). Fixative-perfused brains were processed for microglial immunolabeling with anti-IBA-1 antibodies to analyze cortical microglia. Rats treated with Gln presented an anxiolytic behavior and accelerated CSD propagation when compared to the water- and naive control groups. Furthermore, CSD velocity was higher (p < 0.001) in the L 15 compared to the L 9 condition. Gln treatment increased Iba1 immunolabeling both in the parietal cortex and CA1 hippocampus, indicating microglial activation. The Gln effect was dose-dependent for anxiety-like behavior and CSD in both litter sizes, and for microglial activation in the L 15 groups. Besides confirming previous electrophysiological findings (CSD acceleration after Gln), our data demonstrate for the first time a behavioral and microglial activation that is associated with early Gln treatment in developing animals, and that is possibly operated via changes in brain excitability.

  18. Traveling waves and trial averaging: the nature of single-trial and averaged brain responses in large-scale cortical signals.

    PubMed

    Alexander, David M; Jurica, Peter; Trengove, Chris; Nikolaev, Andrey R; Gepshtein, Sergei; Zvyagintsev, Mikhail; Mathiak, Klaus; Schulze-Bonhage, Andreas; Ruescher, Johanna; Ball, Tonio; van Leeuwen, Cees

    2013-06-01

    Analyzing single trial brain activity remains a challenging problem in the neurosciences. We gain purchase on this problem by focusing on globally synchronous fields in within-trial evoked brain activity, rather than on localized peaks in the trial-averaged evoked response (ER). We analyzed data from three measurement modalities, each with different spatial resolutions: magnetoencephalogram (MEG), electroencephalogram (EEG) and electrocorticogram (ECoG). We first characterized the ER in terms of summation of phase and amplitude components over trials. Both contributed to the ER, as expected, but the ER topography was dominated by the phase component. This means the observed topography of cross-trial phase will not necessarily reflect the phase topography within trials. To assess the organization of within-trial phase, traveling wave (TW) components were quantified by computing the phase gradient. TWs were intermittent but ubiquitous in the within-trial evoked brain activity. At most task-relevant times and frequencies, the within-trial phase topography was described better by a TW than by the trial-average of phase. The trial-average of the TW components also reproduced the topography of the ER; we suggest that the ER topography arises, in large part, as an average over TW behaviors. These findings were consistent across the three measurement modalities. We conclude that, while phase is critical to understanding the topography of event-related activity, the preliminary step of collating cortical signals across trials can obscure the TW components in brain activity and lead to an underestimation of the coherent motion of cortical fields. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Using large-scale neural models to interpret connectivity measures of cortico-cortical dynamics at millisecond temporal resolution

    PubMed Central

    Banerjee, Arpan; Pillai, Ajay S.; Horwitz, Barry

    2012-01-01

    Over the last two decades numerous functional imaging studies have shown that higher order cognitive functions are crucially dependent on the formation of distributed, large-scale neuronal assemblies (neurocognitive networks), often for very short durations. This has fueled the development of a vast number of functional connectivity measures that attempt to capture the spatiotemporal evolution of neurocognitive networks. Unfortunately, interpreting the neural basis of goal directed behavior using connectivity measures on neuroimaging data are highly dependent on the assumptions underlying the development of the measure, the nature of the task, and the modality of the neuroimaging technique that was used. This paper has two main purposes. The first is to provide an overview of some of the different measures of functional/effective connectivity that deal with high temporal resolution neuroimaging data. We will include some results that come from a recent approach that we have developed to identify the formation and extinction of task-specific, large-scale neuronal assemblies from electrophysiological recordings at a ms-by-ms temporal resolution. The second purpose of this paper is to indicate how to partially validate the interpretations drawn from this (or any other) connectivity technique by using simulated data from large-scale, neurobiologically realistic models. Specifically, we applied our recently developed method to realistic simulations of MEG data during a delayed match-to-sample (DMS) task condition and a passive viewing of stimuli condition using a large-scale neural model of the ventral visual processing pathway. Simulated MEG data using simple head models were generated from sources placed in V1, V4, IT, and prefrontal cortex (PFC) for the passive viewing condition. The results show how closely the conclusions obtained from the functional connectivity method match with what actually occurred at the neuronal network level. PMID:22291621

  20. Resting-state functional under-connectivity within and between large-scale cortical networks across three low-frequency bands in adolescents with autism.

    PubMed

    Duan, Xujun; Chen, Heng; He, Changchun; Long, Zhiliang; Guo, Xiaonan; Zhou, Yuanyue; Uddin, Lucina Q; Chen, Huafu

    2017-10-03

    Although evidence is accumulating that autism spectrum disorder (ASD) is associated with disruption of functional connections between and within brain networks, it remains largely unknown whether these abnormalities are related to specific frequency bands. To address this question, network contingency analysis was performed on brain functional connectomes obtained from 213 adolescent participants across nine sites in the Autism Brain Imaging Data Exchange (ABIDE) multisite sample, to determine the disrupted connections between and within seven major cortical networks in adolescents with ASD at Slow-5, Slow-4 and Slow-3 frequency bands and further assess whether the aberrant intra- and inter-network connectivity varied as a function of ASD symptoms. Overall under-connectivity within and between large-scale intrinsic networks in ASD was revealed across the three frequency bands. Specifically, decreased connectivity strength within the default mode network (DMN), between DMN and visual network (VN), ventral attention network (VAN), and between dorsal attention network (DAN) and VAN was observed in the lower frequency band (slow-5, slow-4), while decreased connectivity between limbic network (LN) and frontal-parietal network (FPN) was observed in the higher frequency band (slow-3). Furthermore, weaker connectivity within and between specific networks correlated with poorer communication and social interaction skills in the slow-5 band, uniquely. These results demonstrate intrinsic under-connectivity within and between multiple brain networks within predefined frequency bands in ASD, suggesting that frequency-related properties underlie abnormal brain network organization in the disorder. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Awake craniotomy vs surgery under general anesthesia for resection of supratentorial lesions.

    PubMed

    Sacko, Oumar; Lauwers-Cances, Valérie; Brauge, David; Sesay, Musa; Brenner, Adam; Roux, Franck-Emmanuel

    2011-05-01

    The use of an awake craniotomy in the treatment of supratentorial lesions is a challenge for both patients and staff in the operation theater. To assess the safety and effectiveness of an awake craniotomy with brain mapping in comparison with a craniotomy performed under general anesthesia. We prospectively compared 2 groups of patients who underwent surgery for supratentorial lesions: those in whom an awake craniotomy with intraoperative brain mapping was used (AC group, n = 214) and those in whom surgery was performed under general anesthesia (GA group, n = 361, including 72 patients with lesions in eloquent areas). The AC group included lesions in close proximity to the eloquent cortex that were surgically treated on an elective basis. Globally, the 2 groups were comparable in terms of sex, age, American Society of Anesthesiologists score, pathology, size of lesions, quality of resection, duration of surgery, and neurological outcome, and different in tumor location and preoperative neurological deficits (higher in the AC group). However, specific data analysis of patients with lesions in eloquent areas revealed a significantly better neurological outcome and quality of resection (P < .001) in the AC group than the subgroup of GA patients with lesions in eloquent areas. Surgery was uneventful in AC patients and they were discharged home sooner. AC with brain mapping is safe and allows maximal removal of lesions close to functional areas with low neurological complication rates. It provides an excellent alternative to craniotomy under GA.

  2. Associated Aneurysms in Infratentorial Arteriovenous Malformations: Role of Aneurysm Size and Comparison with Supratentorial Lesions.

    PubMed

    Stein, Klaus-Peter; Wanke, Isabel; Forsting, Michael; Oezkan, Neriman; Huetter, Bernd-Otto; Sandalcioglu, Ibrahim Erol; Sure, Ulrich

    2016-01-01

    The natural history and treatment of brain arteriovenous malformations (AVMs) is the object of ongoing debates and discussions. To capture the entirety of these complex lesions, associated vascular pathologies, such as associated aneurysms (AAs), have to be implemented in future risk stratification models, as they are believed to represent additional risk factors for intracranial hemorrhage. The present study aims to determine AA characteristics in posterior fossa AVMs and to compare with AAs accompanying supratentorial AVMs, with special focus on aneurysm size. Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Only patients with flow-related AAs of the feeding arteries were evaluated. Thus, patients harboring intranidal, venous or remote aneurysms were excluded. Of 485 patients with cerebral AVM, 76 patients harbored an AVM of the posterior fossa. Among those, 22 individuals exhibited a total of 35 AAs (n = 8 patients with multiple AAs). Most common location of AAs was the posterior inferior cerebellar artery (n = 20, 57%) and mean AA diameter was 7.9 mm (SD 5.5). In the subgroup of patients with a single AA, mean aneurysm size in posterior fossa AVMs was with 7.8 mm (SD 6.0; range 2-25 mm) significantly larger than the mean size of AAs with supratentorial AVMs (4.8 mm, SD 3.0; range 2-20 mm; p = 0.048). Intracranial hemorrhage was found in 18 of 22 patients (82%) with infratentorial AVMs, and of these, 11 patients suffered from aneurysm rupture. In 14 patients bearing a single AA, 8 (57%) had sustained hemorrhage from aneurysm rupture. The mean diameter of AAs was as supposed in the ruptured group with 9.8 mm (SD 6.9; range 4-25 mm) significantly larger than in the unruptured AA group exhibiting a mean of 5.0 mm (SD 3.3; range 2-10 mm; p = 0.038). Patients with posterior fossa AVMs and AAs were significantly older as compared to those patients with supratentorial lesions (57.1, SD 12.6 vs. 45.8 years, SD

  3. Properties of voltage-gated potassium currents in nucleated patches from large layer 5 cortical pyramidal neurons of the rat

    PubMed Central

    Bekkers, John M

    2000-01-01

    Voltage-gated potassium currents were studied in nucleated outside-out patches obtained from large layer 5 pyramidal neurons in acute slices of sensorimotor cortex from 13- to 15-day-old Wistar rats (22–25 °C).Two main types of current were found, an A-current (IA) and a delayed rectifier current (IK), which were blocked by 4-aminopyridine (5 mm) and tetraethylammonium (30 mm), respectively.Recovery from inactivation was mono-exponential (for IA) or bi-exponential (for IK) and strongly voltage dependent. Both IA and IK could be almost fully inactivated by depolarising prepulses of sufficient duration. Steady-state inactivation curves were well fitted by the Boltzmann equation with half-maximal voltage (V½) and slope factor (k) values of −81.6 mV and −6.7 mV for IA, and −66.6 mV and −9.2 mV for IK. Peak activation curves were described by the Boltzmann equation with V½ and k values of −18.8 mV and 16.6 mV for IA, and −9.6 mV and 13.2 mV for IK.IA inactivated mono-exponentially during a depolarising test pulse, with a time constant (∼7 ms) that was weakly dependent on membrane potential. IK inactivated bi-exponentially with time constants (∼460 ms, ∼4.2 s) that were also weakly voltage dependent. The time to peak of both IA and IK depended strongly on membrane potential. The kinetics of IA and IK were described by a Hodgkin-Huxley-style equation of the form mNh, where N was 3 for IA and 1 for IK.These results provide a basis for understanding the role of voltage-gated potassium currents in the firing properties of large layer 5 pyramidal neurons of the rat neocortex. PMID:10856115

  4. Large field-of-view and depth-specific cortical microvascular imaging underlies regional differences in ischemic brain

    NASA Astrophysics Data System (ADS)

    Qin, Jia; Shi, Lei; Dziennis, Suzan; Wang, Ruikang K.

    2014-02-01

    Ability to non-invasively monitor and quantify of blood flow, blood vessel morphology, oxygenation and tissue morphology is important for improved diagnosis, treatment and management of various neurovascular disorders, e.g., stroke. Currently, no imaging technique is available that can satisfactorily extract these parameters from in vivo microcirculatory tissue beds, with large field of view and sufficient resolution at defined depth without any harm to the tissue. In order for more effective therapeutics, we need to determine the area of brain that is damaged but not yet dead after focal ischemia. Here we develop an integrated multi-functional imaging system, in which SDW-LSCI (synchronized dual wavelength laser speckle imaging) is used as a guiding tool for OMAG (optical microangiography) to investigate the fine detail of tissue hemodynamics, such as vessel flow, profile, and flow direction. We determine the utility of the integrated system for serial monitoring afore mentioned parameters in experimental stroke, middle cerebral artery occlusion (MCAO) in mice. For 90 min MCAO, onsite and 24 hours following reperfusion, we use SDW-LSCI to determine distinct flow and oxygenation variations for differentiation of the infarction, peri-infarct, reduced flow and contralateral regions. The blood volumes are quantifiable and distinct in afore mentioned regions. We also demonstrate the behaviors of flow and flow direction in the arterials connected to MCA play important role in the time course of MCAO. These achievements may improve our understanding of vascular involvement under pathologic and physiological conditions, and ultimately facilitate clinical diagnosis, monitoring and therapeutic interventions of neurovascular diseases, such as ischemic stroke.

  5. Forelimb amputation-induced reorganization in the ventral posterior lateral nucleus (VPL) provides a substrate for large-scale cortical reorganization in rat forepaw barrel subfield (FBS).

    PubMed

    Li, Cheng X; Chappell, Tyson D; Ramshur, John T; Waters, Robert S

    2014-10-02

    In this study, we examined the role of the ventral posterior lateral nucleus (VPL) as a possible substrate for large-scale cortical reorganization in the forepaw barrel subfield (FBS) of primary somatosensory cortex (SI) that follows forelimb amputation. Previously, we reported that, 6 weeks after forelimb amputation in young adult rats, new input from the shoulder becomes expressed throughout the FBS that quite likely has a subcortical origin. Subsequent examination of the cuneate nucleus (CN) 1 to 30 weeks following forelimb amputation showed that CN played an insignificant role in cortical reorganization and led to the present investigation of VPL. As a first step, we used electrophysiological recordings in forelimb intact adult rats (n=8) to map the body representation in VPL with particular emphasis on the forepaw and shoulder representations and showed that VPL was somatotopically organized. We next used stimulation and recording techniques in forelimb intact rats (n=5) and examined the pattern of projection (a) from the forelimb and shoulder to SI, (b) from the forepaw and shoulder to VPL, and (c) from sites in the forepaw and shoulder representation in VPL to forelimb and shoulder sites in SI. The results showed that the projections were narrowly focused and homotopic. Electrophysiological recordings were then used to map the former forepaw representation in forelimb amputated young adult rats (n=5) at 7 to 24 weeks after amputation. At each time period, new input from the shoulder was observed in the deafferented forepaw region in VPL. To determine whether the new shoulder input in the deafferented forepaw VPL projected to a new shoulder site in the deafferented FBS, we examined the thalamocortical pathway in 2 forelimb-amputated rats. Stimulation of a new shoulder site in deafferented FBS antidromically-activated a cell in the former forepaw territory in VPL; however, similar stimulation from a site in the original shoulder representation, outside the

  6. Sound to Language: Different Cortical Processing for First and Second Languages in Elementary School Children as Revealed by a Large-Scale Study Using fNIRS

    PubMed Central

    Ojima, Shiro; Matsuba-Kurita, Hiroko; Dan, Ippeita; Tsuzuki, Daisuke; Katura, Takusige; Hagiwara, Hiroko

    2011-01-01

    A large-scale study of 484 elementary school children (6–10 years) performing word repetition tasks in their native language (L1-Japanese) and a second language (L2-English) was conducted using functional near-infrared spectroscopy. Three factors presumably associated with cortical activation, language (L1/L2), word frequency (high/low), and hemisphere (left/right), were investigated. L1 words elicited significantly greater brain activation than L2 words, regardless of semantic knowledge, particularly in the superior/middle temporal and inferior parietal regions (angular/supramarginal gyri). The greater L1-elicited activation in these regions suggests that they are phonological loci, reflecting processes tuned to the phonology of the native language, while phonologically unfamiliar L2 words were processed like nonword auditory stimuli. The activation was bilateral in the auditory and superior/middle temporal regions. Hemispheric asymmetry was observed in the inferior frontal region (right dominant), and in the inferior parietal region with interactions: low-frequency words elicited more right-hemispheric activation (particularly in the supramarginal gyrus), while high-frequency words elicited more left-hemispheric activation (particularly in the angular gyrus). The present results reveal the strong involvement of a bilateral language network in children’s brains depending more on right-hemispheric processing while acquiring unfamiliar/low-frequency words. A right-to-left shift in laterality should occur in the inferior parietal region, as lexical knowledge increases irrespective of language. PMID:21350046

  7. Cortical commands in active touch.

    PubMed

    Brecht, Michael

    2006-01-01

    The neocortex is an enormous network of extensively interconnected neurons. It has become clear that the computations performed by individual cortical neurons will critically depend on the quantitative composition of cortical activity. Here we discuss quantitative aspects of cortical activity and modes of cortical processing in the context of rodent active touch. Through in vivo whole-cell recordings one observes widespread subthreshold and very sparse evoked action potential (AP) activity in the somatosensory cortex both for passive whisker deflection in anaesthetized animals and during active whisker movements in awake animals. Neurons of the somatosensory cortex become either suppressed during whisking or activated by an efference copy of whisker movement signal that depolarize cells at certain phases of the whisking cycle. To probe the read out of cortical motor commands we applied intracellular stimulation in rat whisker motor cortex. We find that APs in individual cortical neurons can evoke long sequences of small whisker movements. The capacity of an individual neuron to evoke movements is most astonishing given the large number of neurons in whisker motor cortex. Thus, few cortical APs may suffice to control motor behaviour and such APs can be translated into action with the utmost precision. We conclude that there is very widespread subthreshold cortical activity and very sparse, highly specific cortical AP activity.

  8. Birth weight is positively related to bone size in adolescents but inversely related to cortical bone mineral density: findings from a large prospective cohort study.

    PubMed

    Steer, Colin D; Sayers, Adrian; Kemp, John; Fraser, William D; Tobias, Jon H

    2014-08-01

    To examine the influence of intrauterine environment on subsequent bone development, we investigated the relationship between birth weight and cortical bone parameters, and the role of puberty, bone resorption and insulin as possible mediators. Bone outcomes were obtained from mid-tibial pQCT scans performed at age 15.5 years in 1960 males and 2192 females from the ALSPAC birth cohort. Birth weight was positively related to periosteal circumference (PC) [beta=0.40 (0.34, 0.46)], which was largely but not completely attenuated after adjustment for height and weight [beta=0.07 (0.02, 0.12)] (SD change in outcome per 1 kg increase in birth weight with 95% CI). Based on our height and weight adjusted model, the association was stronger in females compared to males (P=0.02 for gender interaction), and persisted in 2842 participants with equivalent results at age 17.7 years. Conversely, birth weight was inversely related to cortical bone mineral density (BMDC) at age 15.5 years after adjusting for height and weight [beta=-0.18 (-0.23, -0.13)], with a stronger association in males compared to females (P=0.01 for gender interaction), but an equivalent association was not seen at 17.7 years. In further analyses performed on data from age 15.5 years, the association between birth weight and PC was unaffected by adjustment for puberty (Tanner stage at age 13.5 years), bone resorption (fasting beta-carboxyterminal cross linking telopeptide (βCTX) at age 15.5 years) or insulin (fasting insulin at age 15.5 years). In contrast, the association with BMDC was attenuated by approximately 30% after adjustment for puberty or bone resorption, and by 50% after adjustment for both factors combined. We conclude that the inverse relationship between birth weight and BMDC is in part mediated by effects of puberty and bone resorption, which may help to explain the transitory nature of this association, in contrast to the more persisting relationship with PC. Copyright © 2014 The Authors

  9. Hypertensive brainstem encephalopathy involving deep supratentorial regions: does only blood pressure matter?

    PubMed Central

    Park, Jong-Ho; Kim, Sung-Min; Shin, Hyung-Woo; An, Sang Joon

    2010-01-01

    We report on a 42-year-old female patient who presented with high arterial blood pressure of 245/150 mmHg and hypertensive brainstem encephalopathy that involved the brainstem and extensive supratentorial deep gray and white matter. The lesions were nearly completely resolved several days after stabilization of the arterial blood pressure. Normal diffusion-weighted imaging findings and high apparent diffusion coefficient values suggested that the main pathomechanism was vasogenic edema owing to severe hypertension. On the basis of a literature review, the absolute value of blood pressure or whether the patient can control his/her blood pressure seems not to be associated with the degree of the lesions evident on magnetic resonance imaging. It remains to be determined if the acceleration rate and the duration of elevated arterial blood pressure might play a key role in the development of the hypertensive encephalopathy pattern. PMID:21577345

  10. Fatal remote cerebellar hemorrhage after supratentorial unruptured aneurysm surgery in patient with previous cerebellar infarction

    PubMed Central

    Koh, Eun-Jeong; Park, Jung-Soo

    2017-01-01

    Abstract Rationale: Remote cerebellar hemorrhage (RCH) is a rare complication of supratentorial and spinal surgeries, seldom requiring intervention but occasionally causing significant morbidity or even mortality. Although a number of theories have been proposed, the exact pathophysiology of RCH remains incompletely understood. Patient concerns: We present a 62-year-old patient with RCH encountered following surgical clipping of an unruptured middle cerebral artery bifurcation aneurysm in a patient with previous cerebellar infarction. Lessons: It is extremely rare, but sometimes, RCH can be life-threatening. It is necessary to check the patient's general condition, underlying diseases and medical history. And controlled drainage of the CSF seems to be most important. Arachnoidplasty may be a consideration and the position of the drain string might have to be carefully determined. PMID:28121936

  11. Supratentorial extraventricular anaplastic ependymoma in an adult with repeated intratumoral hemorrhage.

    PubMed

    Iwamoto, Naotaka; Murai, Yasuo; Yamamoto, Yoichiro; Adachi, Koji; Teramoto, Akira

    2014-04-01

    We report the case of a 61-year-old man with supratentorial extraventricular anaplastic ependymoma who presented with repeated intratumoral hemorrhage. The patient was admitted with headache. Computed tomography and magnetic resonance imaging showed an enhancing mass with intratumoral hemorrhage in the right temporal lobe. Gross total resection was performed. The tumor was well demarcated from the brain tissue, and showed no continuity with the ventricular system. Histopathological examination revealed the features of anaplastic ependymoma. Therefore, additional radiation therapy and adjuvant chemotherapy were administered. Ten months later, the tumor recurred with hemorrhage in the spinal canal. This case showed rapid malignant progression and repeated intratumoral hemorrhage within a short period of time, both of which are characteristics of anaplastic ependymomas. Close observation of the central nervous system and adjuvant radiotherapy are mandatory, even if the ependymoma presents with repeated intratumoral hemorrhage.

  12. Decompressive surgery for malignant supratentorial infarction remains underutilized after guideline publication.

    PubMed

    Bar, Michal; Mikulik, Robert; Skoloudik, David; Czerny, Daniel; Lipina, Radim; Sames, Martin; Choc, Milan; Novak, Zdenek; Stary, Marian; Benes, Vladimir; Smrcka, Martin; Filip, Michal; Vondrackova, Denisa; Chlouba, Vladimir; Suchomel, Petr; Haninec, Pavel; Brzezny, Richard; Juran, Vilem

    2011-09-01

    Decompressive surgery <48 h from stroke onset reduces the prevalence of mortality and morbidity from malignant supratentorial infarction. We investigated if utilization of decompressive surgery changed in the Czech Republic (CZ) after the release of new guidelines regarding treatment of malignant brain infarction. The volume of decompressive surgery in 2009 in all centers in the CZ was assessed using the same methodology as in 2006. All neurosurgery departments in the CZ were asked to complete a questionnaire and asked to identify all cases of decompressive surgery for malignant brain infarction through a combination of discharge codes for "brain infarction" and "decompressive surgery" from electronic hospital charts. Data for 56 patients were obtained from 15 of the 16 neurosurgery departments in the CZ. The average age was 53 ± 13; number of males 20; median time to surgery was 48 h (range 24-62); median NIHSS score was 25 (IQR, 20-30); median infarct volume was 300 cm(3) [interquartile (IQR, 250-350)]; mean shift on CT was 10.6 ± 3.6 mm and size of hemicraniectomy was 125 cm(2) (IQR, 110-154). A favorable outcome was achieved in 45% of the patients. The number of procedures increased from 39 in 2,006 to 2,056 in 2009. Based on data from one stroke center, 10% suffered from malignant supratentorial infarction and 2.3% met the criteria for decompressive surgery. In 2009, as compared to 2006, the volume of decompressive surgery carried out moderately increased. However, procedures remained underutilized because only ~10% of those who needed decompressive surgery underwent surgery.

  13. Phase I/II Trial of Hyperfractionated Concomitant Boost Proton Radiotherapy for Supratentorial Glioblastoma Multiforme

    SciTech Connect

    Mizumoto, Masashi; Tsuboi, Koji; Igaki, Hiroshi; Yamamoto, Tetsuya; Takano, Shingo; Oshiro, Yoshiko; Hayashi, Yasutaka; Hashii, Haruko; Kanemoto, Ayae; Nakayama, Hidetsugu; Sugahara, Shinji; Sakurai, Hideyuki; Matsumura, Akira; Tokuuye, Koichi

    2010-05-01

    Purpose: To evaluate the safety and efficacy of postoperative hyperfractionated concomitant boost proton radiotherapy with nimustine hydrochloride for supratentorial glioblastoma multiforme (GBM). Methods and Materials: Twenty patients with histologically confirmed supratentorial GBM met the following criteria: (1) a Karnofsky performance status of >=60; (2) the diameter of the enhanced area before radiotherapy was <=40 cm; and (3) the enhanced area did not extend to the brain stem, hypothalamus, or thalamus. Magnetic resonance imaging (MRI) T{sub 2}-weighted high area (clinical tumor volume 3 [CTV3]) was treated by x-ray radiotherapy in the morning (50.4 Gy in 28 fractions). More than 6 hours later, 250 MeV proton beams were delivered to the enhanced area plus a 10-mm margin (CTV2) in the first half of the protocol (23.1 GyE in 14 fractions) and to the enhanced volume (CTV1) in the latter half (23.1 GyE in 14 fraction). The total dose to the CTV1 was 96.6 GyE. Nimustine hydrochloride (80 mg/m2) was administered during the first and fourth weeks. Results: Acute toxicity was mainly hematologic and was controllable. Late radiation necrosis and leukoencephalopathy were each seen in one patient. The overall survival rates after 1 and 2 years were 71.1% and 45.3%, respectively. The median survival period was 21.6 months. The 1- and 2-year progression-free survival rates were 45.0% and 15.5%, respectively. The median MRI change-free survival was 11.2 months. Conclusions: Hyperfractionated concomitant boost proton radiotherapy (96.6 GyE in 56 fractions) for GBM was tolerable and beneficial if the target size was well considered. Further studies are warranted to pursue the possibility of controlling border region recurrences.

  14. Electro-acupuncture decreases postoperative pain and improves recovery in patients undergoing a supratentorial craniotomy.

    PubMed

    An, Li-Xin; Chen, Xue; Ren, Xiu-Jun; Wu, Hai-Feng

    2014-01-01

    We performed this study to examine the effect of electro-acupuncture (EA) on postoperative pain, postoperative nausea and vomiting (PONV) and recovery in patients after a supratentorial tumor resection. Eighty-eight patients requiring a supratentorial tumor resection were anesthetized with sevoflurane and randomly allocated to a no treatment group (Group C) or an EA group (Group A). After anesthesia induction, the patients in Group A received EA at LI4 and SJ5, at BL63 and LR3 and at ST36 and GB40 on the same side as the craniotomy. The stimulation was continued until the end of the operation. Patient-controlled intravenous analgesia (PCIA) was used for the postoperative analgesia. The postoperative pain scores, PONV, the degree of dizziness and appetite were recorded. In the first 6 hours after the operation, the mean total bolus, the effective times of PCIA bolus administrations and the VAS scores were much lower in the EA group (p < 0.05). In the EA group, the incidence of PONV and degree of dizziness and feeling of fullness in the head within the first 24 hours after the operation was much lower than in the control group (p < 0.05). In the EA group, more patients had a better appetite than did the patients in group C (51.2% vs. 27.5%) (p < 0.05). The use of EA in neurosurgery patients improves the quality of postoperative analgesia, promotes appetite recovery and decreases some uncomfortable sensations, such as dizziness and feeling of fullness in the head.

  15. Cortico-cortical communication dynamics

    PubMed Central

    Roland, Per E.; Hilgetag, Claus C.; Deco, Gustavo

    2014-01-01

    In principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG), and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review. PMID:24847217

  16. Critical role of large-conductance calcium- and voltage-activated potassium channels in leptin-induced neuroprotection of N-methyl-d-aspartate-exposed cortical neurons.

    PubMed

    Mancini, Maria; Soldovieri, Maria Virginia; Gessner, Guido; Wissuwa, Bianka; Barrese, Vincenzo; Boscia, Francesca; Secondo, Agnese; Miceli, Francesco; Franco, Cristina; Ambrosino, Paolo; Canzoniero, Lorella Maria Teresa; Bauer, Michael; Hoshi, Toshinori; Heinemann, Stefan H; Taglialatela, Maurizio

    2014-09-01

    In the present study, the neuroprotective effects of the adipokine leptin, and the molecular mechanism involved, have been studied in rat and mice cortical neurons exposed to N-methyl-d-aspartate (NMDA) in vitro. In rat cortical neurons, leptin elicited neuroprotective effects against NMDA-induced cell death, which were concentration-dependent (10-100 ng/ml) and largest when the adipokine was preincubated for 2h before the neurotoxic stimulus. In both rat and mouse cortical neurons, leptin-induced neuroprotection was fully antagonized by paxilline (Pax, 0.01-1 μM) and iberiotoxin (Ibtx, 1-100 nM), with EC50s of 38 ± 10 nM and 5 ± 2 nM for Pax and Ibtx, respectively, close to those reported for Pax- and Ibtx-induced Ca(2+)- and voltage-activated K(+) channels (Slo1 BK channels) blockade; the BK channel opener NS1619 (1-30 μM) induced a concentration-dependent protection against NMDA-induced excitotoxicity. Moreover, cortical neurons from mice lacking one or both alleles coding for Slo1 BK channel pore-forming subunits were insensitive to leptin-induced neuroprotection. Finally, leptin exposure dose-dependently (10-100 ng/ml) increased intracellular Ca(2+) levels in rat cortical neurons. In conclusion, our results suggest that Slo1 BK channel activation following increases in intracellular Ca(2+) levels is a critical step for leptin-induced neuroprotection in NMDA-exposed cortical neurons in vitro, thus highlighting leptin-based intervention via BK channel activation as a potential strategy to counteract neurodegenerative diseases.

  17. CRITICAL ROLE OF LARGE CONDUCTANCE VOLTAGE- AND CALCIUM-ACTIVATED POTASSIUM CHANNELS IN LEPTIN-INDUCED NEUROPROTECTION OF N-METHYL-D-ASPARTATE-EXPOSED CORTICAL NEURONS

    PubMed Central

    Mancini, Maria; Soldovieri, Maria Virginia; Gessner, Guido; Wissuwa, Bianka; Barrese, Vincenzo; Boscia, Francesca; Secondo, Agnese; Miceli, Francesco; Franco, Cristina; Ambrosino, Paolo; Canzoniero, Lorella MariaTeresa; Bauer, Michael; Hoshi, Toshinori; Heinemann, Stefan H; Taglialatela, Maurizio

    2014-01-01

    In the present study, the neuroprotective effects of the adipokine leptin, and the molecular mechanism involved, have been studied in rat and mice cortical neurons exposed to N-methyl-D-Aspartate (NMDA) in vitro. In rat cortical neurons, leptin elicited neuroprotective effects against NMDA-induced cell death which were concentration-dependent (10–100 ng/ml) and largest when the adipokine was preincubated for 2 hours before the neurotoxic stimulus. In both rat and mouse cortical neurons, leptin-induced neuroprotection was fully antagonized by Paxilline (Pax, 0.01–1 μM) and Iberiotoxin (Ibtx, 1–100 nM), two blockers of Ca2+- and voltage-activated K+ channels (Slo1 BK channels), with EC50s (38±10 nM and 5±2 nM for Pax and Ibtx, respectively) close to those reported for Pax- and Ibtx-induced BK channel blockade; the BK channel opener NS1619 (1–30 μM) induced a concentration-dependent protection against NMDA-induced excitotoxicity. Moreover, cortical neurons from mice lacking one or both alleles coding for Slo1 BK channel pore-forming subunits were insensitive to leptin-induced neuroprotection. Finally, leptin exposure dose-dependently (10–100 ng/ml) increased intracellular Ca2+ levels in rat cortical neurons. In conclusion, our results suggest that Slo1 BK channel activation following increases in intracellular Ca2+ levels is a critical step for leptin-induced neuroprotection in NMDA-exposed cortical neurons in vitro, thus highlighting leptin-based intervention via BK channel activation as a potential strategy to counteract neurodegenerative diseases. PMID:24973659

  18. Remifentanil-propofol vs dexmedetomidine-propofol--anesthesia for supratentorial craniotomy.

    PubMed

    Turgut, Namigar; Turkmen, Aygen; Ali, Achmet; Altan, Aysel

    2009-02-01

    The aim of the present study was to compare the perioperative hemodynamics, propofol consumption and recovery profiles of remifentanil and dexmedetomidine when used with air-oxygen and propofol, in order to evaluate a postoperative analgesia strategy and explore undesirable side-effects (nausea, vomiting, shivering). In a prospective randomized double-blind study 50 ASAI-III patients scheduled for supratentorial craniotomy, were allocated into two equal Groups. Group D patients (n = 25), received i.v. dexmedetomidine 1 microg kg(-1) as preinduction over a 15-min period and 0.2-1 microg kg(-1) hr(-1) by continuous i.v. infusion during the operation period. Group R patients (n = 25), received remifentanil 1 microg kg(-1) as induction i.v. over a 15-min period and 0.05-1 microg kg(-1) min(-1) as maintenance. The propofol infusion was started at a rate of 10 mg kg(-1) h(-1) and titrated to maintain BIS in the range 40-50. Propofol doses for induction and maintenance of anesthesia was lower with dexmedetomidine (respectively p < 0.05, p < 0.01). The time for BIS to reach 50 was significantly shorter in Group D (p < 0.01). Comparison of the parameters of recovery revealed; extubation time (p < 0.01); response to verbal commands (p < 0.05) and time for orientation (p < 0.05) were longer with Group D. With respect to Post Anesthesia Care Unit (PACU) discharge time, dexmedetomidine patients required longer time when compared to remifentanil patients to achieve their first normal neurological score (33 min vs 31 min). The earliest opioid administration was at 38 min. in the dexmedetomidine group and 33 min. in the remifentanil group. Propofol-remifentanil and propofol-dexmedetomidine are both suitable for elective supratentorial craniotomy and provide similar intraoperative hemodynamic responses and postoperative adverse events. Propofol-remifentanil allows earlier cognitive recovery; however, it leads to earlier demand for postoperative analgesics. Undesirable side

  19. Cortical Visual Impairment

    MedlinePlus

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased ...

  20. The development of neural synchrony and large-scale cortical networks during adolescence: relevance for the pathophysiology of schizophrenia and neurodevelopmental hypothesis.

    PubMed

    Uhlhaas, Peter J; Singer, Wolf

    2011-05-01

    Recent data from developmental cognitive neuroscience highlight the profound changes in the organization and function of cortical networks during the transition from adolescence to adulthood. While previous studies have focused on the development of gray and white matter, recent evidence suggests that brain maturation during adolescence extends to fundamental changes in the properties of cortical circuits that in turn promote the precise temporal coding of neural activity. In the current article, we will highlight modifications in the amplitude and synchrony of neural oscillations during adolescence that may be crucial for the emergence of cognitive deficits and psychotic symptoms in schizophrenia. Specifically, we will suggest that schizophrenia is associated with impaired parameters of synchronous oscillations that undergo changes during late brain maturation, suggesting an important role of adolescent brain development for the understanding, treatment, and prevention of the disorder. © The Author 2011. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved.

  1. The Development of Neural Synchrony and Large-Scale Cortical Networks During Adolescence: Relevance for the Pathophysiology of Schizophrenia and Neurodevelopmental Hypothesis

    PubMed Central

    Uhlhaas, Peter J.; Singer, Wolf

    2011-01-01

    Recent data from developmental cognitive neuroscience highlight the profound changes in the organization and function of cortical networks during the transition from adolescence to adulthood. While previous studies have focused on the development of gray and white matter, recent evidence suggests that brain maturation during adolescence extends to fundamental changes in the properties of cortical circuits that in turn promote the precise temporal coding of neural activity. In the current article, we will highlight modifications in the amplitude and synchrony of neural oscillations during adolescence that may be crucial for the emergence of cognitive deficits and psychotic symptoms in schizophrenia. Specifically, we will suggest that schizophrenia is associated with impaired parameters of synchronous oscillations that undergo changes during late brain maturation, suggesting an important role of adolescent brain development for the understanding, treatment, and prevention of the disorder. PMID:21505118

  2. Phase II study of DTIC, ACNU, and vincristine combination chemotherapy for supratentorial malignant astrocytomas.

    PubMed

    Ikeda, J; Aida, T; Sawamura, Y; Abe, H; Kaneko, S; Kashiwaba, T; Kawamoto, T; Mitsumori, K; Saitoh, H

    1996-08-01

    This phase II clinical study evaluated the use of 5-(3-3'-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC) pretreatment to reduce cellular resistance and enhance the antitumor effects of chloroethyl nitrosoureas in 32 patients with supratentorial malignant gliomas, including 13 anaplastic astrocytoma and 19 glioblastoma multiforme. All patients received a total dose of 50-65 Gy radiation therapy after surgery. Chemotherapy consisted of DTIC (1 mg/kg) on days 1-5, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (2 mg/kg) on day 5, and vincristine (0.02 mg/kg) on days 1 and 15 every 5 weeks. One patient achieved complete response and 12 patients showed partial response. Median survival time was 18 months and median time-to-progression was 11 months. No significant toxicity was encountered. There was no significant benefit of this pretreatment to combination chemotherapy when compared with previous results. This study does not support a further role for DTIC as a depleter of O6-alkylguanine deoxyribonucleic acid alkyltransferase activity preceding chloroethyl nitrosourea-based chemotherapy.

  3. Long-term supratentorial brain structure and cognitive function following cerebellar tumour resections in childhood.

    PubMed

    Moberget, T; Andersson, S; Lundar, T; Due-Tønnessen, B J; Heldal, A; Endestad, T; Westlye, L T

    2015-03-01

    The cerebellum is connected to extensive regions of the cerebrum, and cognitive deficits following cerebellar lesions may thus be related to disrupted cerebello-cerebral connectivity. Moreover, early cerebellar lesions could affect distal brain development, effectively inducing long-term changes in brain structure and cognitive function. Here, we characterize supratentorial brain structure and cognitive function in 20 adult patients treated for cerebellar tumours in childhood (mean age at surgery: 7.1 years) and 26 matched controls. Relative to controls, patients showed reduced cognitive function and increased grey matter density in bilateral cingulum, left orbitofrontal cortex and the left hippocampus. Within the patient group, increased grey matter density in these regions was associated with decreased performance on tests of processing speed and executive function. Further, diffusion tensor imaging revealed widespread alterations in white matter microstructure in patients. While current ventricle volume (an index of previous hydrocephalus severity it patients) was associated with grey matter density and white matter microstructure in patients, this could only partially account for the observed group differences in brain structure and cognitive function. In conclusion, our results show distal effects of cerebellar lesions on cerebral integrity and wiring, likely caused by a combination of neurodegenerative processes and perturbed neurodevelopment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Supratentorial intracerebral epithelial (ependymal) cysts: review, case reports, and fine structure.

    PubMed Central

    Friede, R L; Yasargil, M G

    1977-01-01

    The paper concerns the rare supratentorial, intracerebral or convexity cysts in adults having a wall lined with an epithelium resembling ependyma. The clincopathological aspects of such cysts are reviewed from 15 published cases and two specimens of the authors which could be examined with the electronmicroscope. These cysts manifest at a median age of 46 years as progressive, space occupying lesions with a fairly rapid clinical course of about one to two years. Twelve of 17 cysts were located in the frontal lobes, most were unequivocally intracerebral and none communicated with the lateral ventricle. Microscopic examination of the cyst wall disclosed some variance in structure, the most common feature being a monolayer of ciliated cells sitting on a very thin collagen membrane. One of the present cases was unique in that the compression by the cyst had caused a shell of infarction in the encompassing tissue. The fine structure of the cysts is described and compared with that of potential host tissues from which such cysts may originate. It is concluded that the cysts arise from displaced segments of the wall of the neural tube which correspond to the sites from which the tela chorioidea forms. Images PMID:864476

  5. Supratentorial cavernous haemangiomas and epilepsy: a review of the literature and case series

    PubMed Central

    Moran, N; Fish, D; Kitchen, N; Shorvon, S; Kendall, B; Stevens, J

    1999-01-01

    OBJECTIVES—To characterise the clinical features and response to treatment of supratentorial cavernomas associated with epilepsy.
METHODS—A systematic review of the literature was carried out and a retrospective case series of patients with cavernoma diagnosed by MRI and/or histology was compiled. Patient selection biases in the literature review were reduced as far as possible by selection of unbiased publications.
RESULTS—In the literature, cavernomas were relatively less common in the frontal lobes. There were multiple cavernomas in 23% of cases. The main clinical manifestations were seizures (79%) and haemorrhage (16%). The annual haemorrhage rate was 0.7%. The outcome after excision was good with improvement in seizures in 92% of patients. In the case series the surgical outcome was less favourable, reflecting inclusion of a higher proportion of patients with intractable epilepsy. In both the literature review and the case series, outcome was poorer in cases with a longer duration of seizures at the time of surgery.
CONCLUSIONS—The good surgical results, particularly in cases treated earlier, and the significant cumulative haemorrhage rate, suggest that excision is the optimum treatment. However, these factors have not been examined prospectively and, despite the availability of several retrospective studies, the optimum treatment, particularly for non-intractable cases, will only be determined by a prospective study.

 PMID:10209164

  6. Effects of Anesthetic Management on Early Postoperative Recovery, Hemodynamics and Pain After Supratentorial Craniotomy

    PubMed Central

    Ayrian, Eugenia; Kaye, Alan David; Varner, Chelsia L.; Guerra, Carolina; Vadivelu, Nalini; Urman, Richard D.; Zelman, Vladimir; Lumb, Philip D.; Rosa, Giovanni; Bilotta, Federico

    2015-01-01

    Various clinical trials have assessed how intraoperative anesthetics can affect early recovery, hemodynamics and nociception after supratentorial craniotomy. Whether or not the difference in recovery pattern differs in a meaningful way with anesthetic choice is controversial. This review examines and compares different anesthetics with respect to wake-up time, hemodynamics, respiration, cognitive recovery, pain, nausea and vomiting, and shivering. When comparing inhalational anesthetics to intravenous anesthetics, either regimen produces similar recovery results. Newer shorter acting agents accelerate the process of emergence and extubation. A balanced inhalational/intravenous anesthetic could be desirable for patients with normal intracranial pressure, while total intravenous anesthesia could be beneficial for patients with elevated intracranial pressure. Comparison of inhalational anesthetics shows all appropriate for rapid emergence, decreasing time to extubation, and cognitive recovery. Comparison of opioids demonstrates similar awakening and extubation time if the infusion of longer acting opioids was ended at the appropriate time. Administration of local anesthetics into the skin, and addition of corticosteroids, NSAIDs, COX-2 inhibitors, and PCA therapy postoperatively provided superior analgesia. It is also important to emphasize the possibility of long-term effects of anesthetics on cognitive function. More research is warranted to develop best practices strategies for the future that are evidence-based. PMID:26345202

  7. Effects of Anesthetic Management on Early Postoperative Recovery, Hemodynamics and Pain After Supratentorial Craniotomy.

    PubMed

    Ayrian, Eugenia; Kaye, Alan David; Varner, Chelsia L; Guerra, Carolina; Vadivelu, Nalini; Urman, Richard D; Zelman, Vladimir; Lumb, Philip D; Rosa, Giovanni; Bilotta, Federico

    2015-10-01

    Various clinical trials have assessed how intraoperative anesthetics can affect early recovery, hemodynamics and nociception after supratentorial craniotomy. Whether or not the difference in recovery pattern differs in a meaningful way with anesthetic choice is controversial. This review examines and compares different anesthetics with respect to wake-up time, hemodynamics, respiration, cognitive recovery, pain, nausea and vomiting, and shivering. When comparing inhalational anesthetics to intravenous anesthetics, either regimen produces similar recovery results. Newer shorter acting agents accelerate the process of emergence and extubation. A balanced inhalational/intravenous anesthetic could be desirable for patients with normal intracranial pressure, while total intravenous anesthesia could be beneficial for patients with elevated intracranial pressure. Comparison of inhalational anesthetics shows all appropriate for rapid emergence, decreasing time to extubation, and cognitive recovery. Comparison of opioids demonstrates similar awakening and extubation time if the infusion of longer acting opioids was ended at the appropriate time. Administration of local anesthetics into the skin, and addition of corticosteroids, NSAIDs, COX-2 inhibitors, and PCA therapy postoperatively provided superior analgesia. It is also important to emphasize the possibility of long-term effects of anesthetics on cognitive function. More research is warranted to develop best practices strategies for the future that are evidence-based.

  8. Adult Supratentorial Low-Grade Glioma: Long-Term Experience at a Single Institution

    SciTech Connect

    Bauman, Glenn; Fisher, Barbara; Watling, Christopher; Cairncross, J. Gregory; Macdonald, David

    2009-12-01

    Purpose: To report the long-term follow-up of a cohort of adult patients with supratentorial low-grade glioma treated at a single institution. Methods and Materials: A cohort of 145 adult patients treated at the London Regional Cancer Program between 1979 and 1995 was reviewed. Results: With a median follow-up of 105 months, the median progression-free survival was 61 months (95% confidence interval, 53-77), and the median overall survival was 118 months (95% confidence interval, 93-129). The 10- and 20-year progression-free and overall survival rate was 18% and 0% and 48% and 22%, respectively. Cox regression analysis confirmed the importance of age, histologic type, presence of seizures, Karnofsky performance status, and initial extent of surgery as prognostic variables for overall and cause-specific survival. Function among long-term survivors without tumor progression was good to excellent for most patients. Conclusion: Low-grade glioma is a chronic disease, with most patients dying of their disease. However, long-term survival with good function is possible. Survival is determined primarily by the disease factors with selection and timing of adjuvant treatments having less influence on outcome.

  9. [Posterior cortical atrophy].

    PubMed

    Solyga, Volker Moræus; Western, Elin; Solheim, Hanne; Hassel, Bjørnar; Kerty, Emilia

    2015-06-02

    Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition. The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group. Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful. Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

  10. P06SUPRATENTORIAL PNET IN ADULTS: MRI CAN HELP DISTINGUISH FROM GLIOBLASTOMA - DWI IS KEY

    PubMed Central

    Eralil, George; Jones, Timothy L.; Howe, Franklyn A.; Barrick, Tom R.; MacKinnon, Andrew D.

    2014-01-01

    INTRODUCTION: Extra-pineal supratentorial primitive neuro-ectodermal tumours (sPNETs) are considered rare in adults and little is known about their radiological appearances. The most clinically relevant pre-surgical differential diagnosis is glioblastoma multiforme (GBM). We present a series of patients with sPNET over a 6 year period (2008-2014), and provide an imaging update with a review of the existing literature. METHOD: Retrospective review of CT and MRI characteristics of 7 patients with histologically proven sPNETs. Comparisons were made with similarly located and histopathologically confirmed WHO Grade 4 GBMs. RESULTS: 6 of the 7 sPNETs occurred de novo. One arose within the resection bed of a WHO Grade 1 pilocytic astrocytoma. There were 4 frontal and 3 temporal lobe incidences. Mean age was 42.8yrs (range 23 - 73 yrs, median 36 yrs). On CT the solid component of the tumour was usually hyperdense. Some of the small sPNETs contained central haemorrhage, confirmed on MRI. Larger tumours were solid/cystic. On MRI the solid component of all sPNETs was T2 hypointense, showed avid enhancement and marked restricted diffusion, typical of a high grade tumour. The degree of restricted diffusion was notably greater in the sPNET group when compared to the GBM cohort. CONCLUSION: The extreme rarity of sPNETs in adults makes for difficult interpretation of existing imaging modalities. In non-histopathologically confirmed cases, imaging could be misinterpreted as high grade glioma. However, greater restricted diffusion in sPNETs may help distinguish them from GBMs. Advanced MRI techniques and correlation with spectroscopy and molecular markers will also help in the future.

  11. Management of supratentorial recurrent low-grade glioma: A multidisciplinary experience in 35 adult patients.

    PubMed

    Spitaels, Julien; Devriendt, Daniel; Sadeghi, Niloufar; Luce, Sylvie; De Witte, Olivier; Goldman, Serge; Mélot, Christian; Lefranc, Florence

    2017-09-01

    The management of recurrent diffuse low-grade gliomas (LGGs) is controversial. In the present study, the multidisciplinary management of 35 patients with recurrent LGGs was retrospectively analyzed. Tumor progression or recurrence was defined by clinical, radiological and/or metabolic pejorative evolution. All patients were regularly followed up by a multidisciplinary neuro-oncological group at Hôpital Erasme. Patients with histologically confirmed supratentorial LGGs (7 astrocytoma, 22 oligodendrogliomas and 6 oligoastrocytomas) who had undergone surgery between August 2004 and November 2010 were included. A total of 3 patients exhibited no tumor progression (median follow-up (FU), 81 months; range, 68-108 months). Tumor recurrence occurred in the 32 remaining patients [progression-free survival (PFS), 26 months; range, 2-104 months]. In addition, 25/29 (86%) patients who received surgery alone underwent reoperation at the time of tumor recurrence, and high-grade transformation occurred in 6 of these patients (24%). Furthermore, 4/29 (14%) patients were treated with adjuvant therapy alone (3 chemotherapy and 1 radiotherapy). In the 19 patients with no high-grade transformation at reintervention, 3 received adjuvant therapy and 16 were regularly followed up through multimodal imaging. The PFS time of the patients who underwent reoperation with close FU (n=16) and for the patients receiving adjuvant therapy with or without surgery (n=7) at first recurrence was 10 and 24 months (P=0.005), respectively. However, no significant difference was observed for overall survival (P=0.403). At the time of this study, 22 of the 35 patients included were alive following a median FU time of 109 months (range, 55-136). The results of the present study could change the multidisciplinary approach used into a more aggressive approach with adjuvant therapy, with or without surgery, for the treatment of a select subpopulation of patients with LGGs at the first instance of tumor

  12. MR Spectroscopy to Distinguish between Supratentorial Intraventricular Subependymoma and Central Neurocytoma.

    PubMed

    Ueda, Fumiaki; Aburano, Hiroyuki; Ryu, Yasuji; Yoshie, Yuichi; Nakada, Mitsutoshi; Hayashi, Yutaka; Matsui, Osamu; Gabata, Toshifumi

    2017-07-10

    The purpose of this study was to discriminate supratentorial intraventricular subependymoma (SIS) from central neurocytoma (CNC) using magnetic resonance spectroscopy (MRS). Single-voxel proton MRS using a 1.5T or 3T MR scanner from five SISs, five CNCs, and normal controls were evaluated. They were examined using a point-resolved spectroscopy. Automatically calculated ratios comparing choline (Cho), N-acetylaspartate (NAA), myoinositol (MI), and/or glycine (Gly) to creatine (Cr) were determined. Evaluation of Cr to unsuppressed water (USW) was also performed. Mann-Whitney U test was carried out to test the significance of differences in the metabolite ratios. Detectability of lactate (Lac) and alanine (Ala) was evaluated. Although a statistically significant difference (P < 0.0001) was observed in Cho/Cr among SIS, control spectra, and CNC, no statistical difference was noted between SIS and control spectra (P = 0.11). Statistically significant differences were observed in NAA/Cr between SIS and CNC (P = 0.04) or control spectra (P < 0.0001). A statistically significant difference was observed in MI and/or Gly to Cr between SIS and control spectra (P = 0.03), and CNC and control spectra (P < 0.0006). There were no statistical differences between SIS and CNC for MI and/or Gly to Cr (P = 0.32). Significant statistical differences were found between SIS and control spectra (P < 0.0053), control spectra and CNC (P < 0.0016), and SIS and CNC (P < 0.0083) for Cr to USW. Lac inverted doublets were confirmed in two SISs. Triplets of Lac and Ala were detected in four spectra of CNC. The present study showed that MRS can be useful in discriminating SIS from CNC.

  13. Supratentorial hemispheric ependymomas: an analysis of 109 adults for survival and prognostic factors.

    PubMed

    Hollon, Todd; Nguyen, Vincent; Smith, Brandon W; Lewis, Spencer; Junck, Larry; Orringer, Daniel A

    2016-08-01

    OBJECTIVE Survival rates and prognostic factors for supratentorial hemispheric ependymomas have not been determined. The authors therefore designed a retrospective study to determine progression-free survival (PFS), overall survival (OS), and prognostic factors for hemispheric ependymomas. METHODS The study population consisted of 8 patients from our institution and 101 patients from the literature with disaggregated survival information (n = 109). Patient age, sex, tumor side, tumor location, extent of resection (EOR), tumor grade, postoperative chemotherapy, radiation, time to recurrence, and survival were recorded. Kaplan-Meier survival analyses and Cox proportional hazard models were completed to determine survival rates and prognostic factors. RESULTS Anaplastic histology/WHO Grade III tumors were identified in 62% of cases and correlated with older age. Three-, 5-, and 10-year PFS rates were 57%, 51%, and 42%, respectively. Three-, 5-, and 10-year OS rates were 77%, 71%, and 58%, respectively. EOR and tumor grade were identified on both Kaplan-Meier log-rank testing and univariate Cox proportional hazard models as prognostic for PFS and OS. Both EOR and tumor grade remained prognostic on multivariate analysis. Subtotal resection (STR) predicted a worse PFS (hazard ratio [HR] 4.764, p = 0.001) and OS (HR 4.216, p = 0.008). Subgroup survival analysis of patients with STR demonstrated a 5- and 10-year OS of 28% and 0%, respectively. WHO Grade III tumors also had worse PFS (HR 10.2, p = 0.004) and OS (HR 9.1, p = 0.035). Patients with WHO Grade III tumors demonstrated 5- and 10-year OS of 61% and 46%, respectively. Postoperative radiation was not prognostic for PFS or OS. CONCLUSIONS A high incidence of anaplastic histology was found in hemispheric ependymomas and was associated with older age. EOR and tumor grade were prognostic factors for PFS and OS on multivariate analysis. STR or WHO Grade III pathology, or both, predicted worse overall prognosis in patients

  14. Neuroimaging of focal cortical dysplasia: neuropathological correlations.

    PubMed

    Colombo, Nadia; Citterio, Alberto; Galli, Carlo; Tassi, Laura; Lo Russo, Giorgio; Scialfa, G; Spreafico, Roberto

    2003-09-01

    Focal cortical dysplasia is a well-known cause of intractable epilepsy with early onset of seizures, and is potentially amenable to surgical therapy. It was first described by Taylor in 1971 as a peculiar malformative disorganisation of the neocortex characterised at histology by loss of cortical lamination and accompanied by giant, dysmorphic neurones and, most frequently, by "balloon cells" littered throughout the cortex and sub-cortical white matter. While in the past decades the term "cortical dysplasia" has referred to various malformations of cortical development, such as agyria, pachygyria, polymicrogyria, heterotopia and hemimegalencephaly, it is now widely accepted that the entity identified by Taylor should be considered separately, from both histological and neuroimaging standpoints. More recently, the recognition of various histological subtypes of focal cortical dysplasia characterised by different degrees of cortical disruption with or without cytological abnormalities has generated several classifications that are still unsatisfactory. With better magnetic resonance capability, subtle and very small focal cortical dysplasias may now be visualised and the differential magnetic resonance aspects of the histological subgroups can be established. We will discuss the problem of histopathological classification and magnetic resonance imaging differentiation of the various subtypes of focal cortical dysplasia in the light of personal data collected from a large series of epileptic patients who underwent surgery and had a histological diagnosis of focal cortical dysplasia. Copyright John Libbey Eurotext 2003.

  15. Lidocaine Reduces Acute Postoperative Pain After Supratentorial Tumor Surgery in the PACU: A Secondary Finding From a Randomized, Controlled Trial.

    PubMed

    Peng, Yuming; Zhang, Wei; Kass, Ira S; Han, Ruquan

    2016-10-01

    Perioperative lidocaine infusion has been reported to reduce postoperative pain in patients after abdominal surgery; however, no study has examined lidocaine's effect on acute postoperative pain after supratentorial tumor surgery. A total of 94 patients scheduled for supratentorial craniotomy were enrolled. Patients received either lidocaine through an intravenous bolus (1.5 mg/kg) after induction followed by infusion at a rate of 2 mg/kg/h until the end of surgery or the same volume of normal saline. Mean arterial blood pressure, heart rate, and bispectral index were recorded at different intraoperative time points. Patients were assessed for pain in the postoperative anesthesia care unit (PACU) by the numeric rating scale (NRS). Other complications including hypertension, tachycardia, dysphoria, and postoperative nausea and vomiting (PONV) were reported. There was no significant difference between the normal saline and lidocaine group for mean arterial blood pressure, heart rate, and bispectral index at any time point (P>0.05). There was no significant difference in the incidence of hypertension, tachycardia, dysphoria, and PONV between groups (P>0.05). The incidence of mild pain (NRS between 1 and 3) after surgery in PACU was lower in lidocaine group than that in the normal saline group (P=0.014); the number of patients with an NRS pain score of 0 before leaving the PACU was significantly greater in the lidocaine group. No patient in either group had moderate or severe pain. Intraoperative infusion of lidocaine significantly decreases the proportion of patients with acute pain after supratentorial tumor surgery in the PACU.

  16. Levetiracetam compared with valproic acid for the prevention of postoperative seizures after supratentorial tumor surgery: a retrospective chart review.

    PubMed

    Lee, Young Jin; Kim, Tackeun; Bae, So Hyun; Kim, Young-Hoon; Han, Jung Ho; Yun, Chang-Ho; Kim, Chae-Yong

    2013-09-01

    Antiepileptic drugs are commonly given for perioperative prophylaxis after brain tumor surgery, and there has been growing interest in levetiracetam, a second-generation antiepileptic drug. This retrospective study compared the seizure outcomes, side effects and durability of levetiracetam with valproic acid after a craniotomy for supratentorial brain tumors. Between 2009 and 2012, 282 consecutive patients with a supratentorial brain tumor underwent a craniotomy at Seoul National University Bundang Hospital. Of these patients, 51 (18.1%) and 231 (81.9%) were pre-operatively administered levetiracetam and valproic acid, respectively. The postoperative seizure outcomes (within 1 month after surgery) and the long-term side effects of both drugs were evaluated. Of the 51 patients in the levetiracetam group, 4 (7.8%) experienced postoperative seizures after brain tumor surgery, and 15 (6.5%) of the 231 patients in the valproic acid group experienced postoperative seizures (p = 0.728). The long-term complication rate of the valproic acid group (26.8%; 62/231) was significantly higher than that of the levetiracetam group (9.8%; 5/51) [p = 0.010]. In the valproic acid group, 10 hepatotoxicities, 20 hyperammonemias and 10 hematologic abnormalities (6 thrombocytopenias, 3 pancytopenias, and 1 leucopenia) occurred. Moreover, 89 patients (38.5%) in the valproic acid group changed or added other anticonvulsants because of side effects or uncontrolled seizures, whereas only 9 patients (17.6%) in the levetiracetam group changed or added other anticonvulsants (p = 0.005). The postoperative seizure control rates of levetiracetam and valproic acid were not statistically significantly different; however, levetiracetam may be superior to valproic acid in terms of its safety and durability after supratentorial tumor surgery.

  17. Surgery for primary supratentorial brain tumors in the United States, 1988 to 2000: The effect of provider caseload and centralization of care

    PubMed Central

    Barker, Fred G.; Curry, William T.; Carter, Bob S.

    2005-01-01

    Contemporary reports of patient outcomes after biopsy or resection of primary brain tumors typically reflect results at specialized centers. Such reports may not be representative of practices in nonspecialized settings. This analysis uses a nationwide hospital discharge database to examine trends in mortality and outcome at hospital discharge in 38,028 admissions for biopsy or resection of supratentorial primary brain tumors in adults between 1988 and 2000, particularly in relation to provider caseload. Multivariate analyses showed that large-volume centers had lower in-hospital postoperative mortality rates than centers with lighter caseloads, both for craniotomies (odds ratio [OR] 0.75 for a tenfold larger caseload) and for needle (closed) biopsies (OR 0.54). Adverse discharge disposition was also less likely at high-volume hospitals, both for craniotomies (OR 0.77) and for needle biopsies (OR 0.67). The annual number of surgical admissions increased by 53% during the 12-year study period, and in-hospital mortality rates decreased during this period, from 4.8% to 1.8%. Mortality rates decreased over time, both for craniotomies and for needle biopsies. Subgroup analyses showed larger relative mortality rate reductions at large-volume centers than at small-volume centers (73% vs. 43%, respectively). The number of U.S. hospitals performing one or more craniotomies annually for primary brain tumors decreased slightly, and the number performing needle biopsies increased. There was little change in median hospital annual craniotomy caseloads, but the largest centers had disproportionate growth in volume. The 100 highest-caseload U.S. hospitals accounted for an estimated 30% of the total U.S. surgical primary brain tumor caseload in 1988 and 41% in 2000. Our findings do not establish minimum volume thresholds for acceptable surgical care of primary brain tumors. However, they do suggest a trend toward progressive centralization of craniotomies for primary brain tumor

  18. Prognostic value of molecular and imaging biomarkers in patients with supratentorial glioma.

    PubMed

    Lopci, Egesta; Riva, Marco; Olivari, Laura; Raneri, Fabio; Soffietti, Riccardo; Piccardo, Arnoldo; Bizzi, Alberto; Navarria, Pierina; Ascolese, Anna Maria; Rudà, Roberta; Fernandes, Bethania; Pessina, Federico; Grimaldi, Marco; Simonelli, Matteo; Rossi, Marco; Alfieri, Tommaso; Zucali, Paolo Andrea; Scorsetti, Marta; Bello, Lorenzo; Chiti, Arturo

    2017-07-01

    We evaluated the relationship between (11)C-methionine PET ((11)C-METH PET) findings and molecular biomarkers in patients with supratentorial glioma who underwent surgery. A consecutive series of 109 patients with pathologically proven glioma (64 men, 45 women; median age 43 years) referred to our Institution from March 2012 to January 2015 for tumour resection and who underwent preoperative (11)C-METH PET were analysed. Semiquantitative evaluation of the (11)C-METH PET images included SUVmax, region of interest-to-normal brain SUV ratio (SUVratio) and metabolic tumour volume (MTV). Imaging findings were correlated with disease outcome in terms of progression-free survival (PFS), and compared with other clinical biological data, including IDH1 mutation status, 1p/19q codeletion and MGMT promoter methylation. The patients were monitored for a mean period of 16.7 months (median 13 months). In all patients, the tumour was identified on (11)C-METH PET. Significant differences in SUVmax, SUVratio and MTV were observed in relation to tumour grade (p < 0.001). IDH1 mutation was found in 49 patients, 1p/19q codeletion in 58 patients and MGMT promoter methylation in 74 patients. SUVmax and SUVratio were significantly inversely correlated with the presence of IDH1 mutation (p < 0.001). Using the 2016 WHO classification, SUVmax and SUVratio were significantly higher in patients with primary glioblastoma (IDH1-negative) than in those with other diffuse gliomas (p < 0.001). Relapse or progression was documented in 48 patients (median PFS 8.7 months). Cox regression analysis showed that SUVmax and SUVratio, tumour grade, tumour type on 2016 WHO classification, IDH1 mutation status, 1p/19q codeletion and MGMT promoter methylation were significantly associated with PFS. None of these factors was found to be an independent prognostic factor in multivariate analysis. (11)C-METH PET parameters are significantly correlated with histological grade and IDH1 mutation status in

  19. Feasibility of Protective Ventilation During Elective Supratentorial Neurosurgery: A Randomized, Crossover, Clinical Trial.

    PubMed

    Ruggieri, Francesco; Beretta, Luigi; Corno, Laura; Testa, Valentina; Martino, Enrico A; Gemma, Marco

    2017-06-30

    Traditional ventilation approaches, providing high tidal volumes (Vt), produce excessive alveolar distention and lung injury. Protective ventilation, employing lower Vt and positive end-expiratory pressure (PEEP), is an attractive alternative also for neuroanesthesia, when prolonged mechanical ventilation is needed. Nevertheless, protective ventilation during intracranial surgery may exert dangerous effects on intracranial pressure (ICP). We tested the feasibility of a protective ventilation strategy in neurosurgery. Our monocentric, double-blind, 1:1 randomized, 2×2 crossover study aimed at studying the effect size and variability of ICP in patients undergoing elective supratentorial brain tumor removal and alternatively ventilated with Vt 9 mL/kg-PEEP 0 mm Hg and Vt 7 mL/kg-PEEP 5 mm Hg. Respiratory rate was adjusted to maintain comparable end-tidal carbon dioxide between ventilation modes. ICP was measured through a subdural catheter inserted before dural opening. Forty patients were enrolled; 8 (15%) were excluded after enrollment. ICP did not differ between traditional and protective ventilation (11.28±5.37, 11 [7 to 14.5] vs. 11.90±5.86, 11 [8 to 15] mm Hg; P=0.541). End-tidal carbon dioxide (28.91±2.28, 29 [28 to 30] vs. 28.00±2.17, 28 [27 to 29] mm Hg; P<0.001). Peak airway pressure (17.25±1.97, 17 [16 to 18.5] vs. 15.81±2.87, 15.5 [14 to 17] mm Hg; P<0.001) and plateau airway pressure (16.06±2.30, 16 [14.5 to 17] vs. 14.19±2.82, 14 [12.5 to 16] mm Hg; P<0.001) were higher during protective ventilation. Blood pressure, heart rate, and body temperature did not differ between ventilation modes. Dural tension was "acceptable for surgery" in all cases. ICP differences between ventilation modes were not affected by ICP values under traditional ventilation (coefficient=0.067; 95% confidence interval, -0.278 to 0.144; P=0.523). Protective ventilation is a feasible alternative to traditional ventilation during elective neurosurgery.

  20. Prediction of coma and anisocoria based on computerized tomography findings in patients with supratentorial intracerebral hemorrhage.

    PubMed

    Song, Zhi; Zheng, Wen; Zhu, Haixia; Chen, Yiwei; Fan, Xuejun; Hou, Deren; Deng, Hao

    2012-07-01

    Coma and anisocoria are the two common signs of a crucial state of neurological dysfunction. The ability to forecast the occurrence of these conditions would help clinicians make clinical risk assessments and decisions. From October 2006 to September 2008, 118 patients with supratentorial intracerebral hemorrhage (SICH) were enrolled in this retrospective investigation. Patients were distributed into 3 groups according to occurrence of the signs of coma and/or anisocoria in the observation unit during a 30-day period. Group 1 included 52 patients who had normal or impaired consciousness, group 2 included 27 patients who had coma with no anisocoria and group 3 consisted of 39 patients who had coma with anisocoria. The clinical characteristics and parameters on computerized tomography (CT) findings were compared using univariate analysis to determine the factors that were related to the level of consciousness. Logistic regression models established the predictive equations for coma and anisocoria. Univariate analysis revealed that hematoma volume, the score of intraventricular hemorrhage (IVH score) and the amplitude of midline shift were the factors related to coma and anisocoria. Mean hematoma volume was 24.0 ± 13.0 ml, 53.6 ± 12.6 ml and 80.5 ± 24.6 ml, the mean amplitudes of midline shift were 1.3 ± 2.0 mm, 5.9 ± 4.9 mm and 10.1 ± 5.5 mm, and the mean IVH score was 0.8 ± 1.3, 3.3 ± 3.3 and 5.9 ± 3.4 in groups 1, 2 and 3, respectively. Multivariate analysis showed that hematoma volume and IVH score were independent prognostic factors for coma and anisocoria. The predictive equations for coma and anisocoria were LogitP = 0.279X(HV) + 0.521X(IVH)-18.164 and LogitP = 0.125X(HV)+0.326X(IVH)-6.864, respectively. Hematoma volume and IVH score were the independent prognostic factors for coma and anisocoria. Logistic regression models established the fitted predictive equations, which could help clinicians make clinical risk assessments and decisions. Crown

  1. Predictors of Hematoma Volume in Deep and Lobar Supratentorial Intracerebral Hemorrhage

    PubMed Central

    Falcone, Guido J.; Biffi, Alessandro; Brouwers, H. Bart; Anderson, Christopher D.; Battey, Thomas W. K.; Ayres, Alison M.; Vashkevich, Anastasia; Schwab, Kristin; Rost, Natalia S.; Goldstein, Joshua N.; Viswanathan, Anand; Greenberg, Steven M.; Rosand, Jonathan

    2013-01-01

    Importance Hematoma volume is the strongest predictor of outcome in intracerebral hemorrhage (ICH). Despite known differences in the underlying biology between deep and lobar ICHs, limited data are available on location specificity of factors reported to affect hematoma volume. Objective To evaluate whether determinants of ICH volume differ by topography, we sought to estimate location-specific effects for potential predictors of this radiological outcome. Design Prospective cohort study. Setting Academic medical center. Participants A total of 744 supratentorial primary ICH patients (388 deep and 356 lobar) aged older than 18 years admitted between January 1, 2000, and December 31, 2010. Main Outcomes and Measures Intracerebral hemorrhage volume measured from the computed tomography scan obtained on presentation to the emergency department. Linear regression analysis, stratified by ICH location, was implemented to identify determinants of log-transformed ICH volume. Results Median ICH volume was larger in lobar hemorrhages (39 mL; interquartile range, 16-75 mL) than in deep hemorrhages (13 mL; interquartile range, 5-40 mL; P<.001). In multivariable linear regression, independent predictors of deep ICH volume were intensity of anticoagulation (β=0.32; standard error [SE]=0.08; P<.001; test for trend across 4 categories of the international normalized ratio), history of coronary artery disease (β=0.33; SE=0.17; P=.05), male sex (β=0.28; SE=0.14; P=.05), and age (β=−0.02; SE=0.01; P=.001). Independent predictors of lobar ICH volume were intensity of anticoagulation (β=0.14; SE=0.06; P=.02) and antiplatelet treatment (β=0.27; SE=0.13; P=.03). Conclusions and Relevance Predictors of hematoma volume only partially overlap between deep and lobar ICHs. These findings suggest that the mechanisms that determine the extent of bleeding differ for deep and lobar ICHs. Further studies are needed to characterize the specific biological pathways that underlie the observed

  2. Role of surgery in the management of patients with supratentorial spontaneous intracerebral hematoma: Critical appraisal of evidence.

    PubMed

    Akhigbe, Taiwo; Zolnourian, Ardalan

    2017-05-01

    Whether surgery improves the outcome more than medical management alone continues to be a subject of intense debate and controversy. However, there is optimism that the management of spontaneous supratentorial intracerebral haemorrhage will change in future based new insight and better understanding of the acute pathophysiology of hematomas and its dynamics. Craniotomy as a surgical approach has been the most studied intervention for spontaneous supratentorial intracerebral haemorrhage but with no significant benefit when compared to best medical management. A literature search was conducted using electronic data bases including the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane library, MEDLINE and EMBASE. In addition, critical appraisal of most current evidences was carried out. About 1387 articles identified through database search over 10-year period of which one systematic review and two randomised controlled trials most relevant to this review were critically appraised. The role of surgery in the management of spontaneous intracerebral haemorrhage still remains a matter of debate. There is insufficient evidence to justify a general policy of early surgery for patients with spontaneous intracerebral haemorrhage compared to initial medical management but STICH did demonstrate that patients with superficial hematoma might benefit from craniotomy. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  3. Cognitive function after radiotherapy for supratentorial low-grade glioma: A North Central Cancer Treatment Group prospective study

    SciTech Connect

    Laack, Nadia N.; Brown, Paul D. . E-mail: brown.paul@mayo.edu; Ivnik, Robert J.; Furth, Alfred F. M.S.; Ballman, Karla V.; Hammack, Julie E.; Arusell, Robert M.; Shaw, Edward G.; Buckner, Jan C.

    2005-11-15

    Purpose: To evaluate the effects of cranial radiotherapy (RT) on cognitive function in patients with supratentorial low-grade glioma. Methods and Materials: Twenty adult patients with supratentorial low-grade glioma were treated with 50.4 Gy (10 patients) or 64.8 Gy (10 patients) localized RT. The patients then were evaluated with an extensive battery of psychometric tests at baseline (before RT) and at approximately 18-month intervals for as long as 5 years after completing RT. To allow patients to serve as their own controls, cognitive performance was evaluated as change in scores over time. All patients underwent at least two evaluations. Results: Baseline test scores were below average compared with age-specific norms. At the second evaluation, the groups' mean test scores were higher than their initial performances on all psychometric measures, although the improvement was not statistically significant. No changes in cognitive performance were seen during the evaluation period when test scores were analyzed by age, treatment, tumor location, tumor type, or extent of resection. Conclusions: Cognitive function was stable after RT in these patients evaluated prospectively during 3 years of follow-up. Slight improvements in some cognitive areas are consistent with practice effects attributable to increased familiarity with test procedures and content.

  4. Early and late postoperative seizure outcome in 97 patients with supratentorial meningioma and preoperative seizures: a retrospective study.

    PubMed

    Zheng, Zhe; Chen, Peng; Fu, Weiming; Zhu, Junming; Zhang, Hong; Shi, Jian; Zhang, Jianmin

    2013-08-01

    We identified factors associated with early and late postoperative seizure control in patients with supratentorial meningioma plus preoperative seizures. In this retrospective study, univariate analysis and multivariate logistic regression analysis compared 24 clinical variables according to the occurrence of early (≤1 week) or late (>1 week) postoperative seizures. Sixty-two of 97 patients (63.9 %) were seizure free for the entire postoperative follow-up period (29.5 ± 11.8 months), while 13 patients (13.4 %) still had frequent seizures at the end of follow-up. Fourteen of 97 patients (14.4 %) experienced early postoperative seizures, and emergence of new postoperative neurological deficits was the only significant risk factor (odds ratio = 7.377). Thirty-three patients (34.0 %) experienced late postoperative seizures at some time during follow-up, including 12 of 14 patients with early postoperative seizures. Associated risk factors for late postoperative seizures included tumor progression (odds ratio = 7.012) and new permanent postoperative neurological deficits (odds ratio = 4.327). Occurrence of postoperative seizures in patients with supratentorial meningioma and preoperative seizure was associated with new postoperative neurological deficits. Reduced cerebral or vascular injury during surgery may lead to fewer postoperative neurological deficits and better seizure outcome.

  5. Cognitive function after radiotherapy for supratentorial low-grade glioma: a North Central Cancer Treatment Group prospective study.

    PubMed

    Laack, Nadia N; Brown, Paul D; Ivnik, Robert J; Furth, Alfred F; Ballman, Karla V; Hammack, Julie E; Arusell, Robert M; Shaw, Edward G; Buckner, Jan C

    2005-11-15

    To evaluate the effects of cranial radiotherapy (RT) on cognitive function in patients with supratentorial low-grade glioma. Twenty adult patients with supratentorial low-grade glioma were treated with 50.4 Gy (10 patients) or 64.8 Gy (10 patients) localized RT. The patients then were evaluated with an extensive battery of psychometric tests at baseline (before RT) and at approximately 18-month intervals for as long as 5 years after completing RT. To allow patients to serve as their own controls, cognitive performance was evaluated as change in scores over time. All patients underwent at least two evaluations. Baseline test scores were below average compared with age-specific norms. At the second evaluation, the groups' mean test scores were higher than their initial performances on all psychometric measures, although the improvement was not statistically significant. No changes in cognitive performance were seen during the evaluation period when test scores were analyzed by age, treatment, tumor location, tumor type, or extent of resection. Cognitive function was stable after RT in these patients evaluated prospectively during 3 years of follow-up. Slight improvements in some cognitive areas are consistent with practice effects attributable to increased familiarity with test procedures and content.

  6. Cortical Odor Processing in Health and Disease

    PubMed Central

    Wilson, Donald A.; Xu, Wenjin; Sadrian, Benjamin; Courtiol, Emmanuelle; Cohen, Yaniv; Barnes, Dylan C.

    2014-01-01

    The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer’s disease, Parkinson’s disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity? PMID:24767487

  7. Dynamics of large-scale cortical interactions at high gamma frequencies during word production: Event related causality (ERC) analysis of human electrocorticography (ECoG)

    PubMed Central

    Korzeniewska, Anna; Franaszczuk, Piotr J.; Crainiceanu, Ciprian M.; Kuś, Rafał; Crone, Nathan E.

    2011-01-01

    Intracranial EEG studies in humans have shown that functional brain activation in a variety of functional-anatomic domains of human cortex is associated with an increase in power at a broad range of high gamma (> 60 Hz) frequencies. Although these electrophysiological responses are highly specific for the location and timing of cortical processing and in animal recordings are highly correlated with increased population firing rates, there has been little direct empirical evidence for causal interactions between different recording sites at high gamma frequencies. Such causal interactions are hypothesized to occur during cognitive tasks that activate multiple brain regions. To determine whether such causal interactions occur at high gamma frequencies and to investigate their functional significance, we used event-related causality (ERC) analysis to estimate the dynamics, directionality, and magnitude of event-related causal interactions using subdural electrocorticography (ECoG) recorded during two word production tasks: picture naming and auditory word repetition. A clinical subject who had normal hearing but was skilled in American Signed Language (ASL) provided a unique opportunity to test our hypothesis with reference to a predictable pattern of causal interactions, i.e. that language cortex interacts with different areas of sensorimotor cortex during spoken vs. signed responses. Our ERC analyses confirmed this prediction. During word production with spoken responses, perisylvian language sites had prominent causal interactions with mouth/tongue areas of motor cortex, and when responses were gestured in sign language, the most prominent interactions involved hand and arm areas of motor cortex. Furthermore, we found that the sites from which the most numerous and prominent causal interactions originated, i.e. sites with a pattern of ERC “divergence”, were also sites where high gamma power increases were most prominent and where electrocortical stimulation

  8. Dynamics of large-scale cortical interactions at high gamma frequencies during word production: event related causality (ERC) analysis of human electrocorticography (ECoG).

    PubMed

    Korzeniewska, Anna; Franaszczuk, Piotr J; Crainiceanu, Ciprian M; Kuś, Rafał; Crone, Nathan E

    2011-06-15

    Intracranial EEG studies in humans have shown that functional brain activation in a variety of functional-anatomic domains of human cortex is associated with an increase in power at a broad range of high gamma (>60Hz) frequencies. Although these electrophysiological responses are highly specific for the location and timing of cortical processing and in animal recordings are highly correlated with increased population firing rates, there has been little direct empirical evidence for causal interactions between different recording sites at high gamma frequencies. Such causal interactions are hypothesized to occur during cognitive tasks that activate multiple brain regions. To determine whether such causal interactions occur at high gamma frequencies and to investigate their functional significance, we used event-related causality (ERC) analysis to estimate the dynamics, directionality, and magnitude of event-related causal interactions using subdural electrocorticography (ECoG) recorded during two word production tasks: picture naming and auditory word repetition. A clinical subject who had normal hearing but was skilled in American Signed Language (ASL) provided a unique opportunity to test our hypothesis with reference to a predictable pattern of causal interactions, i.e. that language cortex interacts with different areas of sensorimotor cortex during spoken vs. signed responses. Our ERC analyses confirmed this prediction. During word production with spoken responses, perisylvian language sites had prominent causal interactions with mouth/tongue areas of motor cortex, and when responses were gestured in sign language, the most prominent interactions involved hand and arm areas of motor cortex. Furthermore, we found that the sites from which the most numerous and prominent causal interactions originated, i.e. sites with a pattern of ERC "divergence", were also sites where high gamma power increases were most prominent and where electrocortical stimulation mapping

  9. The effect of the results of the STICH trial on the management of spontaneous supratentorial intracerebral haemorrhage in Newcastle.

    PubMed

    Kirkman, M A; Mahattanakul, W; Gregson, B A; Mendelow, A D

    2008-12-01

    Recently, the Surgical Trial in IntraCerebral Haemorrhage (STICH) was unable to show an overall benefit from 'early surgery' compared with a policy of 'initial conservative treatment'. Here, we evaluated the impact of the STICH results on the management of spontaneous supratentorial intracerebral haemorrhage (ICH) in the Newcastle upon Tyne Hospitals. The STICH results were released to the Neurosurgery Department at Newcastle General Hospital in November 2003; using ICD-10 data, we analysed ICH admissions before (2002) and after (2004, 2006, 2007) this. We assessed numbers of Neurosurgery and Stroke Unit admissions, numbers of clot evacuation procedures, and 30-day mortality rate (Neurosurgery vs. Stroke Unit admissions). Subarachnoid haemorrhage (SAH) admissions data were also collected to corroborate our findings. There were 478 spontaneous supratentorial ICH admissions in total; 156 in 2002, 120 in 2004, 106 in 2006 and 96 in 2007. SAH admissions remained remarkably constant over this period. Neurosurgery admissions decreased significantly across the four time periods, from 71% of total ICH admissions (n = 156) in 2002 to 55% (n = 96) in 2007, and Stroke Unit admissions increased significantly from 8% (n = 156) in 2002 to 30% (n = 96) in 2007 (chi(2) = 20.968, p < 0.001, df = 3). Clot evacuation procedures also decreased significantly from 32% (n = 111) of Neurosurgery admissions in 2002 to 17% (n = 53) in 2007 (chi(2) = 11.919, p = 0.008, df = 3). 30-day mortality increased in Neurosurgery from 14% of Neurosurgery admissions (n = 111) in 2002 to 26% (n = 53) in 2007, and decreased in the Stroke Unit, from 42% of Stroke Unit admissions (n = 12) in 2002 to 17% (n = 29) in 2007. The STICH results have significantly impacted ICH management in Newcastle, with a trend towards fewer Neurosurgery admissions and clot evacuations, and increased Stroke Unit admissions. The role of surgery for ICH remains controversial, and randomization continues in STICH II for patients

  10. Effect of malaria in pregnancy on foetal cortical brain development: a longitudinal observational study.

    PubMed

    Rijken, Marcus J; de Wit, Merel Charlotte; Mulder, Eduard J H; Kiricharoen, Suporn; Karunkonkowit, Noaeni; Paw, Tamalar; Visser, Gerard H A; McGready, Rose; Nosten, François H; Pistorius, Lourens R

    2012-07-02

    Malaria in pregnancy has a negative impact on foetal growth, but it is not known whether this also affects the foetal nervous system. The aim of this study was to examine the effects of malaria on foetal cortex development by three-dimensional ultrasound. Brain images were acquired using a portable ultrasound machine and a 3D ultrasound transducer. All recordings were analysed, blinded to clinical data, using the 4D view software package. The foetal supra-tentorial brain volume was determined and cortical development was qualitatively followed by scoring the appearance and development of six sulci. Multilevel analysis was used to study brain volume and cortical development in individual foetuses. Cortical grading was possible in 161 out of 223 (72%) serial foetal brain images in pregnant women living in a malaria endemic area. There was no difference between foetal cortical development or brain volumes at any time in pregnancy between women with immediately treated malaria infections and non-infected pregnancies. The percentage of images that could be graded was similar to other neuro-sonographic studies. Maternal malaria does not have a gross effect on foetal brain development, at least in this population, which had access to early detection and effective treatment of malaria.

  11. Biomechanics of Single Cortical Neurons

    PubMed Central

    Bernick, Kristin B.; Prevost, Thibault P.; Suresh, Subra; Socrate, Simona

    2011-01-01

    This study presents experimental results and computational analysis of the large strain dynamic behavior of single neurons in vitro with the objective of formulating a novel quantitative framework for the biomechanics of cortical neurons. Relying on the atomic force microscopy (AFM) technique, novel testing protocols are developed to enable the characterization of neural soma deformability over a range of indentation rates spanning three orders of magnitude – 10, 1, and 0.1 μm/s. Modified spherical AFM probes were utilized to compress the cell bodies of neonatal rat cortical neurons in load, unload, reload and relaxation conditions. The cell response showed marked hysteretic features, strong non-linearities, and substantial time/rate dependencies. The rheological data were complemented with geometrical measurements of cell body morphology, i.e. cross-diameter and height estimates. A constitutive model, validated by the present experiments, is proposed to quantify the mechanical behavior of cortical neurons. The model aimed to correlate empirical findings with measurable degrees of (hyper-) elastic resilience and viscosity at the cell level. The proposed formulation, predicated upon previous constitutive model developments undertaken at the cortical tissue level, was implemented into a three-dimensional finite element framework. The simulated cell response was calibrated to the experimental measurements under the selected test conditions, providing a novel single cell model that could form the basis for further refinements. PMID:20971217

  12. Measurable Supratentorial White Matter Volume Changes in Patients with Diffuse Intrinsic Pontine Glioma Treated with an Anti-Vascular Endothelial Growth Factor Agent, Steroids, and Radiation.

    PubMed

    Svolos, P; Reddick, W E; Edwards, A; Sykes, A; Li, Y; Glass, J O; Patay, Z

    2017-06-01

    Assessing the response to treatment in infiltrative brain tumors by using lesion volume-based response criteria is challenging. We hypothesized that in such tumors, volume measurements alone may not accurately capture changes in actual tumor burden during treatment. We longitudinally evaluated volume changes in both normal-appearing supratentorial white matter and the brain stem lesions in patients treated for diffuse intrinsic pontine glioma to determine to what extent adjuvant systemic therapies may skew the accuracy of tumor response assessments based on volumetric analysis. The anatomic MR imaging and diffusion tensor imaging data of 26 patients with diffuse intrinsic pontine glioma were retrospectively analyzed. Treatment included conformal radiation therapy in conjunction with vandetanib and dexamethasone. Volumetric and diffusion data were analyzed with time, and differences between time points were evaluated statistically. Normalized brain stem lesion volume decreased during combined treatment (slope = -0.222, P < .001) and increased shortly after completion of radiation therapy (slope = 0.422, P < .001). Supratentorial white matter volume steadily and significantly decreased with time (slope = -0.057, P < .001). Longitudinal changes in brain stem lesion volume are robust; less pronounced but measurable changes occur in the supratentorial white matter. Volume changes in nonirradiated supratentorial white matter during the disease course reflect the effects of systemic medication on the water homeostasis of normal parenchyma. Our data suggest that adjuvant nontumor-targeted therapies may have a more substantial effect on lesion volume changes than previously thought; hence, an apparent volume decrease in infiltrative tumors receiving combined therapies may lead to overestimation of the actual response and tumor control. © 2017 by American Journal of Neuroradiology.

  13. Intraoperative and postoperative anaesthetic and analgesic effect of multipoint transcutaneous electrical acupuncture stimulation combined with sufentanil anaesthesia in patients undergoing supratentorial craniotomy.

    PubMed

    Liu, Xing; Li, Shuqin; Wang, Baoguo; An, Lixin; Ren, Xiujun; Wu, Haifeng

    2015-08-01

    To investigate the anaesthetic and analgesic effect of multipoint transcutaneous electrical acupuncture stimulation (TEAS) during supratentorial tumour resection for postoperative recovery and side effects. In a blinded clinical trial, 92 patients scheduled for supratentorial craniotomy under general anaesthesia were randomly allocated into either a multipoint TEAS (n=46) or a sham TEAS group (n=46). All patients received total intravenous anaesthesia (TIVA) with propofol and sufentanil. The target concentration of sufentanil was adjusted and recorded according to mean arterial pressure (MAP), heart rate (HR) and bispectral index (BIS). Patients in the TEAS group received TEAS 30 min before anaesthesia induction and this was maintained throughout the operation at four pairs of acupuncture points. Postoperative pain, recovery and side effects were evaluated. Eighty-eight patients completed the study. Continuous monitoring of MAP, HR and BIS showed stable values with no significant differences between the two groups (p>0.05). Sufentanil target plasma concentration in TEAS patients was significantly lower at some time points during supratentorial craniotomy, and total sufentanil consumption was significantly higher in the sham group (p<0.05). Postoperative recovery and pain were significantly improved by TEAS (p<0.001), without the postoperative side effects. Multipoint TEAS at both proximal and distal points combined with TIVA can significantly decrease intraoperative sufentanil requirements, increase pain relief on postoperative day 1 and improve postoperative recovery of patients during supratentorial tumour resection, with no significant increase of side effects. These findings suggest that multipoint TEAS may be clinically effective as an adjunct to analgesia in intraoperative anaesthesia and postoperative pain treatment and may speed recovery. Chinese Clinical Trial Registry (registration number ChiCTR-TRC-10001078). Published by the BMJ Publishing Group Limited

  14. Multiresolution Diffeomorphic Mapping for Cortical Surfaces.

    PubMed

    Tan, Mingzhen; Qiu, Anqi

    2015-01-01

    Due to the convoluted folding pattern of the cerebral cortex, accurate alignment of cortical surfaces remains challenging. In this paper, we present a multiresolution diffeomorphic surface mapping algorithm under the framework of large deformation diffeomorphic metric mapping (LDDMM). Our algorithm takes advantage of multiresolution analysis (MRA) for surfaces and constructs cortical surfaces at multiresolution. This family of multiresolution surfaces are used as natural sparse priors of the cortical anatomy and provide the anchor points where the parametrization of deformation vector fields is supported. This naturally constructs tangent bundles of diffeomorphisms at different resolution levels and hence generates multiresolution diffeomorphic transformation. We show that our construction of multiresolution LDDMM surface mapping can potentially reduce computational cost and improves the mapping accuracy of cortical surfaces.

  15. Evolution of cortical neurogenesis.

    PubMed

    Abdel-Mannan, Omar; Cheung, Amanda F P; Molnár, Zoltán

    2008-03-18

    The neurons of the mammalian neocortex are organised into six layers. By contrast, the reptilian and avian dorsal cortices only have three layers which are thought to be equivalent to layers I, V and VI of mammals. Increased repertoire of mammalian higher cognitive functions is likely a result of an expanded cortical surface area. The majority of cortical cell proliferation in mammals occurs in the ventricular zone (VZ) and subventricular zone (SVZ), with a small number of scattered divisions outside the germinal zone. Comparative developmental studies suggest that the appearance of SVZ coincides with the laminar expansion of the cortex to six layers, as well as the tangential expansion of the cortical sheet seen within mammals. In spite of great variation and further compartmentalisation in the mitotic compartments, the number of neurons in an arbitrary cortical column appears to be remarkably constant within mammals. The current challenge is to understand how the emergence and elaboration of the SVZ has contributed to increased cortical cell diversity, tangential expansion and gyrus formation of the mammalian neocortex. This review discusses neurogenic processes that are believed to underlie these major changes in cortical dimensions in vertebrates.

  16. Spontaneous vertebral artery dissection with multiple supratentorial and infratentorial acute infarcts in the posterior circulation Case report.

    PubMed

    I, Cristea; C, Popa

    2016-01-01

    The article represents a case of a young patient with atypical clinical and paraclinical presentation of vertebral artery dissection by multiple cerebral infarcts, localized at the supratentorial and infratentorial levels in the posterior circulation. A case of a 21-year-old man, without a history of trauma in the cervical area or at the cranial level, without recent chiropractic maneuvers or practicing a sport, which required rapid, extreme, rotational movements of the neck, was examined. He presented to the emergency room with nausea, numbness of the left limbs, dysarthria, and incoordination of walking, with multiple objective signs at the neurological examination, which revealed right vertebral artery subacute dissection after the paraclinical investigations. The case was particular due to the atypical debut symptomatology, through the installation of the clinical picture in stages, during 4 hours and by multiple infarcts through the artery-to-artery embolic mechanism in the posterior cerebral territory. Abbreviations: PICA = posterior inferior cerebellar artery, CT = computed tomography, MRI = magnetic resonance imaging, angio MRI = mangnetic resonance angiography, FLAIR = fluid attenuated inversion recovery, FS = fat suppression, ADC = apparent diffusion coefficient, DWI = diffusion weighted imaging, T1/ T2 = T1/ T2 weighted image-basic pulse sequences in MRI, VA = vertebral artery, 3D-TOF = 3D Time of Flight.

  17. Extent of resection and survival in supratentorial infiltrative low-grade gliomas: analysis of and adjustment for treatment bias.

    PubMed

    Gousias, Konstantinos; Schramm, Johannes; Simon, Matthias

    2014-02-01

    Any correlation between the extent of resection and the prognosis of patients with supratentorial infiltrative low-grade gliomas may well be related to biased treatment allocation. Patients with an intrinsically better prognosis may undergo more aggressive resections, and better survival may then be falsely attributed to the surgery rather than the biology of the disease. The present study investigates the potential impact of this type of treatment bias on survival in a series of patients with low-grade gliomas treated at the authors' institution. We conducted a retrospective study of 148 patients with low-grade gliomas undergoing primary treatment at our institution from 1996-2011. Potential prognostic factors were studied in order to identify treatment bias and to adjust survival analyses accordingly. Eloquence of tumor location proved the most powerful predictor of the extent of resection, i.e., the principal source of treatment bias. Univariate as well as multivariate Cox regression analyses identified the extent of resection and the presence of a preoperative neurodeficit as the most important predictors of overall survival, tumor recurrence and malignant progression. After stratification for eloquence of tumor location in order to correct for treatment bias, Kaplan-Meier estimates showed a consistent association between the degree of resection and improved survival. Treatment bias was not responsible for the correlation between extent of resection and survival observed in the present series. Our data seem to provide further support for a strategy of maximum safe resections for low-grade gliomas.

  18. Spontaneous vertebral artery dissection with multiple supratentorial and infratentorial acute infarcts in the posterior circulation Case report

    PubMed Central

    Cristea, I; Popa, C

    2016-01-01

    The article represents a case of a young patient with atypical clinical and paraclinical presentation of vertebral artery dissection by multiple cerebral infarcts, localized at the supratentorial and infratentorial levels in the posterior circulation. A case of a 21-year-old man, without a history of trauma in the cervical area or at the cranial level, without recent chiropractic maneuvers or practicing a sport, which required rapid, extreme, rotational movements of the neck, was examined. He presented to the emergency room with nausea, numbness of the left limbs, dysarthria, and incoordination of walking, with multiple objective signs at the neurological examination, which revealed right vertebral artery subacute dissection after the paraclinical investigations. The case was particular due to the atypical debut symptomatology, through the installation of the clinical picture in stages, during 4 hours and by multiple infarcts through the artery-to-artery embolic mechanism in the posterior cerebral territory. Abbreviations: PICA = posterior inferior cerebellar artery, CT = computed tomography, MRI = magnetic resonance imaging, angio MRI = mangnetic resonance angiography, FLAIR = fluid attenuated inversion recovery, FS = fat suppression, ADC = apparent diffusion coefficient, DWI = diffusion weighted imaging, T1/ T2 = T1/ T2 weighted image-basic pulse sequences in MRI, VA = vertebral artery, 3D-TOF = 3D Time of Flight PMID:27974938

  19. Cortical pathways to the mammalian amygdala.

    PubMed

    McDonald, A J

    1998-06-01

    The amygdaloid nuclear complex is critical for producing appropriate emotional and behavioral responses to biologically relevant sensory stimuli. It constitutes an essential link between sensory and limbic areas of the cerebral cortex and subcortical brain regions, such as the hypothalamus, brainstem, and striatum, that are responsible for eliciting emotional and motivational responses. This review summarizes the anatomy and physiology of the cortical pathways to the amygdala in the rat, cat and monkey. Although the basic anatomy of these systems in the cat and monkey was largely delineated in studies conducted during the 1970s and 1980s, detailed information regarding the cortico-amygdalar pathways in the rat was only obtained in the past several years. The purpose of this review is to describe the results of recent studies in the rat and to compare the organization of cortico-amygdalar projections in this species with that seen in the cat and monkey. In all three species visual, auditory, and somatosensory information is transmitted to the amygdala by a series of modality-specific cortico-cortical pathways ("cascades") that originate in the primary sensory cortices and flow toward higher order association areas. The cortical areas in the more distal portions of these cascades have stronger and more extensive projections to the amygdala than the more proximal areas. In all three species olfactory and gustatory/visceral information has access to the amygdala at an earlier stage of cortical processing than visual, auditory and somatosensory information. There are also important polysensory cortical inputs to the mammalian amygdala from the prefrontal and hippocampal regions. Whereas the overall organization of cortical pathways is basically similar in all mammalian species, there is anatomical evidence which suggests that there are important differences in the extent of convergence of cortical projections in the primate versus the nonprimate amygdala.

  20. Cortical Neural Computation by Discrete Results Hypothesis.

    PubMed

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called "Discrete Results" (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of "Discrete Results" is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel "Discrete Results" concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast-spiking (FS

  1. Cortical Neural Computation by Discrete Results Hypothesis

    PubMed Central

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called “Discrete Results” (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of “Discrete Results” is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel “Discrete Results” concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast

  2. Potent stimulation of large-conductance Ca2+-activated K+ channels by rottlerin, an inhibitor of protein kinase C-delta, in pituitary tumor (GH3) cells and in cortical neuronal (HCN-1A) cells.

    PubMed

    Wu, Sheng-Nan; Wang, Ya-Jean; Lin, Ming-Wei

    2007-03-01

    The effects of rottlerin, a known inhibitor of protein kinase C-delta activation, on ion currents were investigated in pituitary tumor (GH3) cells. Rottlerin (0.3-100 microM) increased the amplitude of Ca2+-activated K+ current (I K(Ca)) in a concentration-dependent manner with an EC50 value of 1.7 microM. In intracellular perfusion with rottlerin (1 microM) or staurosporine (10 microM), phorbol 12-myristate 13-acetate-induced inhibition of I K(Ca) in these cells was abolished. In cell-attached mode, rottlerin applied on the extracellular side of the membrane caused activation of large-conductance Ca2+-activated K+ (BK(Ca)) channels, and a further application of BAPTA-AM (10 microM) to the bath had no effect on rottlerin-stimulated channel activity. When cells were exposed to rottlerin, the activation curve of these channels was shifted to less positive potential with no change in the slope factor. Rottlerin increased BK(Ca)-channel activity in outside-out patches. Its change in kinetic behavior of BK(Ca) channels is primarily due to an increase in mean open time. With the aid of minimal kinetic scheme, a quantitative description of rottlerin stimulation on BK(Ca) channels in GH3 cells was also provided. Under current-clamp configuration, rottlerin (1 microM) decreased the firing of action potentials. I K(Ca) elicited by simulated action potential waveforms was enhanced by this compound. In human cortical HCN-1A cells, rottlerin (1 microM) could also interact with the BK(Ca) channel to stimulate I K(Ca). Therefore, rottlerin may directly activate BK(Ca) channels in neurons or endocrine cells.

  3. Variation-based sparse cortical current density imaging in estimating cortical sources with MEG data.

    PubMed

    Ding, Lei; Zhu, Min; Zhang, Wenbo; Dickens, Deanna L

    2010-01-01

    We investigated the performance of a new sparse neuroimaging method, i.e., Variation-Based Sparse Cortical Current Density (VB-SCCD) using magnetoencephalography (MEG) data to reconstruct extended cortical sources and their spatial distributions on the cortical surface. We conducted Monte Carlo simulation studies to compare the performance of the VB-SCCD method with different number of cortical sources and different number of MEG sensors. Our simulation data suggests that the VB-SCCD method is able to reconstruct extended cortical sources with the overall accuracy, while it has significantly reduced performance when cortical sources are radially oriented to MEG sensors. It has higher accuracy when the number of sensors is large and the source configuration is simple. We further assess the performance of VB-SCCD in real MEG data from an epilepsy patient and reconstructed cortical sources behind interictal spikes from the patient which are consistent with the clinical evaluation outcomes. This data indicate its promising applications in clinical problems related to neurological disorders.

  4. Mechanisms of Hierarchical Cortical Maturation

    PubMed Central

    Chomiak, Taylor; Hu, Bin

    2017-01-01

    Cortical information processing is structurally and functionally organized into hierarchical pathways, with primary sensory cortical regions providing modality specific information and associative cortical regions playing a more integrative role. Historically, there has been debate as to whether primary cortical regions mature earlier than associative cortical regions, or whether both primary and associative cortical regions mature simultaneously. Identifying whether primary and associative cortical regions mature hierarchically or simultaneously will not only deepen our understanding of the mechanisms that regulate brain maturation, but it will also provide fundamental insight into aspects of adolescent behavior, learning, neurodevelopmental disorders and computational models of neural processing. This mini-review article summarizes the current evidence supporting the sequential and hierarchical nature of cortical maturation, and then proposes a new cellular model underlying this process. Finally, unresolved issues associated with hierarchical cortical maturation are also addressed. PMID:28959187

  5. Proton Radiation Therapy for Pediatric Medulloblastoma and Supratentorial Primitive Neuroectodermal Tumors: Outcomes for Very Young Children Treated With Upfront Chemotherapy

    SciTech Connect

    Jimenez, Rachel B.; Sethi, Roshan; Depauw, Nicolas; Pulsifer, Margaret B.; Adams, Judith; McBride, Sean M.; Ebb, David; Fullerton, Barbara C.; Tarbell, Nancy J.; Yock, Torunn I.; MacDonald, Shannon M.

    2013-09-01

    Purpose: To report the early outcomes for very young children with medulloblastoma or supratentorial primitive neuroectodermal tumor (SPNET) treated with upfront chemotherapy followed by 3-dimensional proton radiation therapy (3D-CPT). Methods and Materials: All patients aged <60 months with medulloblastoma or SPNET treated with chemotherapy before 3D-CPT from 2002 to 2010 at our institution were included. All patients underwent maximal surgical resection, chemotherapy, and adjuvant 3D-CPT with either craniospinal irradiation followed by involved-field radiation therapy or involved-field radiation therapy alone. Results: Fifteen patients (median age at diagnosis, 35 months) were treated with high-dose chemotherapy and 3D-CPT. Twelve of 15 patients had medulloblastoma; 3 of 15 patients had SPNET. Median time from surgery to initiation of radiation was 219 days. Median craniospinal irradiation dose was 21.6 Gy (relative biologic effectiveness); median boost dose was 54.0 Gy (relative biologic effectiveness). At a median of 39 months from completion of radiation, 1 of 15 was deceased after a local failure, 1 of 15 had died from a non-disease-related cause, and the remaining 13 of 15 patients were alive without evidence of disease recurrence. Ototoxicity and endocrinopathies were the most common long-term toxicities, with 2 of 15 children requiring hearing aids and 3 of 15 requiring exogenous hormones. Conclusions: Proton radiation after chemotherapy resulted in good disease outcomes for a small cohort of very young patients with medulloblastoma and SPNET. Longer follow-up and larger numbers of patients are needed to assess long-term outcomes and late toxicity.

  6. Identification of high versus lower risk clinical subgroups in a group of adult patients with supratentorial anaplastic astrocytomas.

    PubMed

    Decaestecker, C; Salmon, I; Camby, I; Dewitte, O; Pasteels, J L; Brotchi, J; Van Ham, P; Kiss, R

    1995-05-01

    The present work investigates whether computer-assisted techniques can contribute any significant information to the characterization of astrocytic tumor aggressiveness. Two complementary computer-assisted methods were used. The first method made use of the digital image analysis of Feulgen-stained nuclei, making it possible to compute 15 morphonuclear and 8 nuclear DNA content-related (ploidy level) parameters. The second method enabled the most discriminatory parameters to be determined. This second method is the Decision Tree technique, which forms part of the Supervised Learning Algorithms. These two techniques were applied to a series of 250 supratentorial astrocytic tumors of the adult. This series included 39 low-grade (astrocytomas, AST) and 211 high-grade (47 anaplastic astrocytomas, ANA, and 164 glioblastomas, GBM) astrocytic tumors. The results show that some AST, ANA and GBM did not fit within simple logical rules. These "complex" cases were labeled NC-AST, NC-ANA and NC-GBM because they were "non-classical" (NC) with respect to their cytological features. An analysis of survival data revealed that the patients with NC-GBM had the same survival period as patients with GBM. In sharp contrast, patients with ANA survived significantly longer than patients with NC-ANA. In fact, the patients with ANA had the same survival period as patients who died from AST, while the patients with NC-ANA had a survival period similar to those with GBM. All these data show that the computer-assisted techniques used in this study can actually provide the pathologist with significant information on the characterization of astrocytic tumor aggressiveness.

  7. Radiation Is an Important Component of Multimodality Therapy for Pediatric Non-Pineal Supratentorial Primitive Neuroectodermal Tumors

    SciTech Connect

    McBride, Sean M.; Daganzo, Sally M.; Banerjee, Anuradha; Gupta, Nalin; Lamborn, Kathleen R.; Prados, Michael D.; Berger, Mitchel S.; Wara, William M.; Haas-Kogan, Daphne A.

    2008-12-01

    Purpose: To review a historical cohort of pediatric patients with supratentorial primitive neuroectodermal tumors (sPNET), to clarify the role of radiation in the treatment of these tumors. Patients and Methods: Fifteen children aged <18 years with non-pineal sPNETs diagnosed between 1992 and 2006 were identified. Initial therapy consisted of surgical resection and chemotherapy in all patients and up-front radiotherapy (RT) in 5 patients. Five patients had RT at the time of progression, and 5 received no RT whatever. Kaplan-Meier estimates of overall survival were then calculated. Results: The median follow-up from diagnosis for all patients was 31 months (range, 0.5-165 months) and for surviving patients was 49 months (range, 10-165). Of the 5 patients who received up-front RT, all were alive without evidence of disease at a median follow-up of 50 months (range, 25-165 months). Only 5 of the 10 patients who did not receive up-front RT were alive at last follow-up. There was a statistically significant difference in overall survival between the patient group that received up-front RT and the group that did not (p = 0.048). In addition, we found a trend toward a statistically significant improvement in overall survival for those patients who received gross total resections (p = 0.10). Conclusions: Up-front RT and gross total resection may confer a survival benefit in patients with sPNET. Local failure was the dominant pattern of recurrence. Efforts should be made to determine patients most likely to have local failure exclusively or as a first recurrence, in order to delay or eliminate craniospinal irradiation.

  8. Supratentorial primitive neuroectodermal tumors (S-PNET) in children: A prospective experience with adjuvant intensive chemotherapy and hyperfractionated accelerated radiotherapy

    SciTech Connect

    Massimino, Maura . E-mail: maura.massimino@istitutotumori.mi.it; Gandola, Lorenza; Spreafico, Filippo; Luksch, Roberto; Collini, Paola; Giangaspero, Felice; Simonetti, Fabio; Casanova, Michela; Cefalo, Graziella; Pignoli, Emanuele; Ferrari, Andrea; Terenziani, Monica; Podda, Marta; Meazza, Cristina; Polastri, Daniela; Poggi, Geraldina; Ravagnani, Fernando; Fossati-Bellani, Franca

    2006-03-15

    Purpose: Supratentorial primitive neuroectodermal tumors (S-PNET) are rare and have a grim prognosis, frequently taking an aggressive course with local relapse and metastatic spread. We report the results of a mono-institutional therapeutic trial. Methods and Materials: We enrolled 15 consecutive patients to preradiation chemotherapy (CT) consisting of high-dose methotrexate, high-dose etoposide, high-dose cyclophosphamide, and high-dose carboplatin, craniospinal irradiation (CSI) with hyperfractionated accelerated radiotherapy (HART) plus focal boost, maintenance with vincristine/lomustine or consolidation with high-dose thiotepa followed by autologous stem-cell rescue. Results: Median age was 9 years; 7 were male, 8 female. Site of disease was pineal in 3, elsewhere in 12. Six patients were had no evidence of disease after surgery (NED). Of those with evidence of disease after surgery (ED), 2 had central nervous system spread. Of the 9 ED patients, 2 had complete response (CR) and 2 partial response (PR) after CT, 4 stable disease, and 1 progressive disease. Of the 7 ED patients before radiotherapy, 1 had CR, 4 PR, and 2 minor response, thus obtaining a 44% CR + PR after CT and 71% after HART. Because of rapid progression in 2 of the first 5 patients, high-dose thiotepa was systematically adopted after HART in the subsequent 10 patients. Six of 15 patients relapsed (4 locally, 1 locally with dissemination, 1 with dissemination) a mean of 6 months after starting CT, 2 developed second tumors; 5 of 6 relapsers died at a median of 13 months. Three-year progression-free survival, event-free survival, and overall survival were 54%, 34%, and 61%, respectively. Conclusion: Hyperfractionated accelerated RT was the main tool in obtaining responses in S-PNET; introducing the myeloablative phase improved the prognosis (3/10 vs. 3/5 relapses), though the outcome remained unsatisfactory despite the adoption of this intensive treatment.

  9. Application of high-definition fiber tractography in the management of supratentorial cavernous malformations: a combined qualitative and quantitative approach.

    PubMed

    Abhinav, Kumar; Pathak, Sudhir; Richardson, R Mark; Engh, Johnathan; Gardner, Paul; Yeh, Fang-Cheng; Friedlander, Robert M; Fernandez-Miranda, Juan C

    2014-06-01

    High-definition fiber tractography (HDFT), an advanced white matter (WM) imaging technique, was evaluated in the management of supratentorial cavernous malformations. To investigate the relationship of cavernous malformations to the relevant perilesional WM tracts with HDFT and to characterize associated changes first qualitatively and then quantitatively with our novel imaging measure, quantitative anisotropy (QA). Imaging analysis was carried out by researchers blinded to the clinical details. Contralateral WM tracts were used for comparison. Mean QA values were obtained for whole WM tracts. Qualitatively affected superior longitudinal fasciculus/arcuate fibers and corticospinal tracts were further analyzed with the use of mean QA values for the perilesional segments. Of 10 patients, HDFT assisted with the decision-making process and the offer of surgical resection in 2 patients, lesion approach and removal in 7 patients, and conservative management in 1 patient. Of 17 analyzed WM tracts, HDFT demonstrated partial disruption in 2 tracts, complete disruption in 2 tracts, a combination of displacement and partial disruption in 1 tract, displacement only in 7 tracts, and no change in 5 tracts. Qualitative changes correlated with clinical symptoms. Mean QA values for the whole WM tracts were similar, with the exception of 1 case demonstrating complete disruption of 2 WM tracts. QA-based perilesional segment analysis was consistent with qualitative data in 5 assessed WM tracts. HDFT illustrated the precise spatial relationship of cavernous malformations to multiple WM tracts in a 3-dimensional fashion, optimizing surgical planning, and demonstrated associated disruption and/or displacement, with both occurring perilesionally. These changes were supported by our quantitative marker, which needs further validation.

  10. Safety and Efficacy of a Novel, Self-Adhering Dural Substitute in a Canine Supratentorial Durotomy Model.

    PubMed

    Lewis, Kevin M; Sweet, Jenifer; Wilson, Scott T; Rousselle, Serge; Gulle, Heinz; Baumgartner, Bernhard

    2017-06-01

    Cerebrospinal fluid (CSF) leaks increase postoperative risk for complication, likelihood of reoperation, and costs. To investigate a novel, self-adhering polyethylene glycol-coated collagen pad (PCC) as a dural substitute relative to Duragen XS (DGX; Integra LifeSciences Corporation, Plainsboro, New Jersey) and as a dural sealant relative to Tachosil (Takeda Austria GmbH, Linz, Austria), a fibrinogen and thrombin-coated collagen pad (FTC). A canine supratentorial durotomy surgical model was used to investigate the safety and efficacy of PCC. For safety, 4 animals were bilaterally treated with DGX or PCC and recovered for 1, 8, or 16 wk; total 24 animals. Each animal underwent physical and neurological examinations weekly and 16-wk animals underwent a magnetic resonance imaging (MRI) examination at each time point. For efficacy, 9 animals were unilaterally treated with FTC or PCC and underwent a burst pressure test intraoperatively or 14 d postoperatively; total 36 animals. In the safety study, no abnormal clinical signs or changes were noted on physical and neurological examinations, or in clinical pathology, CSF analysis or histopathology of DGX or PCC-treated animals. No consistent signs of cerebral compression, CSF leak, hemorrhage, or hydrocephalus were noted on MRI. In the efficacy study, no significant difference was found between FTC and PCC at each time point or overall (13.9 vs 12.3 mm Hg, n = 18 per group, P = .46). PCC is safe for use as a dural substitute and effective as a dural sealant. The novel, self-adhering combination of a polyethylene glycol-based sealant and a collagen pad may offer unique benefits to the advancement of duraplasty.

  11. Epidural cortical stimulation and aphasia therapy

    PubMed Central

    Cherney, Leora R.; Harvey, Richard L.; Babbitt, Edna M.; Hurwitz, Rosalind; Kaye, Rosalind C.; Lee, Jaime B.; Small, Steven. L.

    2013-01-01

    Background There are several methods of delivering cortical brain stimulation to modulate cortical excitability and interest in their application as an adjuvant strategy in aphasia rehabilitation after stroke is growing. Epidural cortical stimulation, although more invasive than other methods, permits high frequency stimulation of high spatial specificity to targeted neuronal populations. Aims First, we review evidence supporting the use of epidural cortical stimulation for upper limb recovery after focal cortical injury in both animal models and human stroke survivors. These data provide the empirical and theoretical platform underlying the use of epidural cortical stimulation in aphasia. Second, we summarize evidence for the application of epidural cortical stimulation in aphasia. We describe the procedures and primary outcomes of a safety and feasibility study (Cherney, Erickson & Small, 2010), and provide previously unpublished data regarding secondary behavioral outcomes from that study. Main Contribution In a controlled study comparing epidural cortical stimulation plus language treatment (CS/LT) to language treatment alone (LT), eight stroke survivors with nonfluent aphasia received intensive language therapy for 6 weeks. Four of these participants also underwent surgical implantation of an epidural stimulation device which was activated only during therapy sessions. Behavioral data were collected before treatment, immediately after treatment, and at 6 and 12 weeks following the end of treatment. The effect size for the primary outcome measure, the Western Aphasia Battery Aphasia Quotient, was benchmarked as moderate from baseline to immediately post-treatment, and large from baseline to the 12-week follow-up. Similarly, effect sizes obtained at the 12-week follow-up for the Boston Naming Test, the Communicative Effectiveness Index, and for correct information units on a picture description task were greater than those obtained immediately post treatment

  12. Mapping cortical mesoscopic networks of single spiking cortical or sub-cortical neurons.

    PubMed

    Xiao, Dongsheng; Vanni, Matthieu P; Mitelut, Catalin C; Chan, Allen W; LeDue, Jeffrey M; Xie, Yicheng; Chen, Andrew Cn; Swindale, Nicholas V; Murphy, Timothy H

    2017-02-04

    Understanding the basis of brain function requires knowledge of cortical operations over wide-spatial scales, but also within the context of single neurons. In vivo, wide-field GCaMP imaging and sub-cortical/cortical cellular electrophysiology were used in mice to investigate relationships between spontaneous single neuron spiking and mesoscopic cortical activity. We make use of a rich set of cortical activity motifs that are present in spontaneous activity in anesthetized and awake animals. A mesoscale spike-triggered averaging procedure allowed the identification of motifs that are preferentially linked to individual spiking neurons by employing genetically targeted indicators of neuronal activity. Thalamic neurons predicted and reported specific cycles of wide-scale cortical inhibition/excitation. In contrast, spike-triggered maps derived from single cortical neurons yielded spatio-temporal maps expected for regional cortical consensus function. This approach can define network relationships between any point source of neuronal spiking and mesoscale cortical maps.

  13. Visualization of Cortical Dynamics

    NASA Astrophysics Data System (ADS)

    Grinvald, Amiram

    2003-03-01

    Recent progress in studies of cortical dynamics will be reviewed including the combination of real time optical imaging based on voltage sensitive dyes, single and multi- unit recordings, LFP, intracellular recordings and microstimulation. To image the flow of neuronal activity from one cortical site to the next, in real time, we have used optical imaging based on newly designed voltage sensitive dyes and a Fuji 128x 128 fast camera which we modified. A factor of 20-40 fold improvement in the signal to noise ratio was obtained with the new dye during in vivo imaging experiments. This improvements has facilitates the exploration of cortical dynamics without signal averaging in the millisecond time domain. We confirmed that the voltage sensitive dye signal indeed reflects membrane potential changes in populations of neurons by showing that the time course of the intracellular activity recorded intracellularly from a single neuron was highly correlated in many cases with the optical signal from a small patch of cortex recorded nearby. We showed that the firing of single cortical neurons is not a random process but occurs when the on-going pattern of million of neurons is similar to the functional architecture map which correspond to the tuning properties of that neuron. Chronic optical imaging, combined with electrical recordings and microstimulation, over a long period of times of more than a year, was successfully applied also to the study of higher brain functions in the behaving macaque monkey.

  14. The involvement of supratentorial white matter in multiple system atrophy: a diffusion tensor imaging tractography study.

    PubMed

    Wang, Po-Shan; Yeh, Chien-Li; Lu, Chia-Feng; Wu, Hsiu-Mei; Soong, Bing-Wen; Wu, Yu-Te

    2017-03-01

    It has been assumed that cognitive disorder and visual-spatial disturbance in multiple system atrophy of the predominantly cerebellar type (MSA-C) are attributable to degradation of cerebellar function. The purpose of this study was to use diffusion tensor imaging (DTI) tractography to determine if patients with MSA-C characterized in part by visual-spatial disorders and cognitive disorders have changes of the structural connectivity network of nerve fibers, and to further describe the structural connectivity network. The study included 20 patients with MSA-C and 30 age- and sex-matched healthy controls. A 1.5T magnetic resonance imaging (MRI) scanner was used to obtain images for DTI tractography. Image preprocessing was done by large deformation diffeomorphic metric mapping. Whole-brain connectivity analysis was carried out. The patients had decreased numbers of long association fibers connecting the right parietal lobe to the frontal lobe. The commissural fibers and short association fibers connecting the bilateral frontal and occipital lobes and the number of short association fibers at the bilateral frontal and occipital region were also decreased significantly. The patients had a significant decrease in fiber density in the cerebellum compared to the healthy subjects. Our results provide DTI evidence suggesting that frontal and occipital white matter is involved in patients with MSA-C. This finding may correlate with their clinical symptoms such as cognitive disturbance as well as visual-spatial impairment. Therefore, cognitive disturbance and visual-spatial deficits in MSA-C might not be due to cerebellar lesions only as is widely believed but also involve cerebral lesions.

  15. Gyrification from constrained cortical expansion

    PubMed Central

    Tallinen, Tuomas; Chung, Jun Young; Biggins, John S.; Mahadevan, L.

    2014-01-01

    The exterior of the mammalian brain—the cerebral cortex—has a conserved layered structure whose thickness varies little across species. However, selection pressures over evolutionary time scales have led to cortices that have a large surface area to volume ratio in some organisms, with the result that the brain is strongly convoluted into sulci and gyri. Here we show that the gyrification can arise as a nonlinear consequence of a simple mechanical instability driven by tangential expansion of the gray matter constrained by the white matter. A physical mimic of the process using a layered swelling gel captures the essence of the mechanism, and numerical simulations of the brain treated as a soft solid lead to the formation of cusped sulci and smooth gyri similar to those in the brain. The resulting gyrification patterns are a function of relative cortical expansion and relative thickness (compared with brain size), and are consistent with observations of a wide range of brains, ranging from smooth to highly convoluted. Furthermore, this dependence on two simple geometric parameters that characterize the brain also allows us to qualitatively explain how variations in these parameters lead to anatomical anomalies in such situations as polymicrogyria, pachygyria, and lissencephalia. PMID:25136099

  16. Quantitative radiology: radiogrammetry of cortical bone.

    PubMed

    Dequeker, J

    1976-11-01

    Based on personal experience and data in the literature, an overview is given of radiogrammetry of cortical bone of the second metacarpal. There is a within- and between-observer error which amounts respectively to 1.2 and 1.5% for the outer diameter and 4.8 and 6.4% for the inner diameter. The systematic + or-- trend between observers indicates that one observer working according to certain defined rules obtains the most reliable results. There is a large variability in amount of bone within one age and sex group which is partly due to skeletal size differences, are insufficient since skeletal size differences still exist. The variability is reduced when the data are divided into strata of skeletal size. Since cortical area shows the best correlation with outer diameter within each age group and since cortical area represents best the ash content of the bones the values of this index are most suited to be grouped according to outer diameter. In differentiating pathological from physiological bone loss this procedure is an improvement on the previously published indices of amount of bone. When comparing different populations this method has advantages since skeletal size differences are eliminated. Comparing seven populations it was found that populations living in the United States of America have more bone for a given skeletal size than populations in Europe or Nigeria. Bone loss with age is a general phenomenon but differences in rate of loss are observed between the sexes and between ethnic different populations. The decrease of bone mass is faster after the age of 50 years in woman than in men. Blacks living in the United States loose less bone with age than whites. Radiogrammetry of cortical bone in groups gives useful information on bond remodelling during ageing and in pathological conditions. At an individual level, however, it is difficult to evaluate changes on a short term basis with radiogrammetry. Radiogrammetry of cortical bone is a simple and

  17. Prolonged impairment of deglutition in supratentorial ischaemic stroke: the predictive value of Parramatta Hospitals' Assessment of Dysphagia.

    PubMed

    Kägi, Georg; Leisi, Natascha; Galovic, Marian; Müller-Baumberger, Marlise; Krammer, Werner; Weder, Bruno

    second assessment. In these patients, ROC analysis of PHAD recorded 8 to 10 days after the stroke showed excellent accuracy with an AUC of 0.971 (cut-off 71.5) predicting a BODS-2 score of ≥4 at final evaluation. The accuracy of ROC analysis of the PHAD score assessed within 48 hours of stroke onset to predict prolonged impairment of deglutition was poor (AUC 0.685). In a selected population at risk of aspiration, the PHAD with a threshold of 70 assessed in the second week after stroke onset may be a valuable tool to predict prolonged impairment of deglutition for another 4 weeks and to guide the decision about switching from NG to PEG tube feeding after supratentorial ischaemic stroke.

  18. Differences in supratentorial damage of white matter in pediatric survivors of posterior fossa tumors with and without adjuvant treatment as detected by magnetic resonance diffusion tensor imaging.

    PubMed

    Rueckriegel, Stefan Mark; Driever, Pablo Hernáiz; Blankenburg, Friederike; Lüdemann, Lutz; Henze, Günter; Bruhn, Harald

    2010-03-01

    To elucidate morphologic correlates of brain dysfunction in pediatric survivors of posterior fossa tumors by using magnetic resonance diffusion tensor imaging (DTI) to examine neuroaxonal integrity in white matter. Seventeen medulloblastoma (MB) patients who had received surgery and adjuvant treatment, 13 pilocytic astrocytoma (PA) patients who had been treated only with surgery, and age-matched healthy control subjects underwent magnetic resonance imaging on a 3-Tesla system. High-resolution conventional T1- and T2-weighted magnetic resonance imaging and DTI data sets were obtained. Fractional anisotropy (FA) maps were analyzed using tract-based spatial statistics, a part of the Functional MRI of the Brain Software Library. Compared with control subjects, FA values of MB patients were significantly decreased in the cerebellar midline structures, in the frontal lobes, and in the callosal body. Fractional anisotropy values of the PA patients were not only decreased in cerebellar hemispheric structures as expected, but also in supratentorial parts of the brain, with a distribution similar to that in MB patients. However, the amount of significantly decreased FA was greater in MB than in PA patients, underscoring the aggravating neurotoxic effect of the adjuvant treatment. Neurotoxic mechanisms that are present in PA patients (e.g., internal hydrocephalus and damaged cerebellar structures affecting neuronal circuits) contribute significantly to the alteration of supratentorial white matter in pediatric posterior fossa tumor patients. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  19. Differences in Supratentorial Damage of White Matter in Pediatric Survivors of Posterior Fossa Tumors With and Without Adjuvant Treatment as Detected by Magnetic Resonance Diffusion Tensor Imaging

    SciTech Connect

    Rueckriegel, Stefan Mark; Driever, Pablo Hernaiz; Blankenburg, Friederike; Luedemann, Lutz; Henze, Guenter; Bruhn, Harald

    2010-03-01

    Purpose: To elucidate morphologic correlates of brain dysfunction in pediatric survivors of posterior fossa tumors by using magnetic resonance diffusion tensor imaging (DTI) to examine neuroaxonal integrity in white matter. Patients and Methods: Seventeen medulloblastoma (MB) patients who had received surgery and adjuvant treatment, 13 pilocytic astrocytoma (PA) patients who had been treated only with surgery, and age-matched healthy control subjects underwent magnetic resonance imaging on a 3-Tesla system. High-resolution conventional T1- and T2-weighted magnetic resonance imaging and DTI data sets were obtained. Fractional anisotropy (FA) maps were analyzed using tract-based spatial statistics, a part of the Functional MRI of the Brain Software Library. Results: Compared with control subjects, FA values of MB patients were significantly decreased in the cerebellar midline structures, in the frontal lobes, and in the callosal body. Fractional anisotropy values of the PA patients were not only decreased in cerebellar hemispheric structures as expected, but also in supratentorial parts of the brain, with a distribution similar to that in MB patients. However, the amount of significantly decreased FA was greater in MB than in PA patients, underscoring the aggravating neurotoxic effect of the adjuvant treatment. Conclusions: Neurotoxic mechanisms that are present in PA patients (e.g., internal hydrocephalus and damaged cerebellar structures affecting neuronal circuits) contribute significantly to the alteration of supratentorial white matter in pediatric posterior fossa tumor patients.

  20. Whisker stimulation metabolically activates thalamus following cortical transplantation but not following cortical ablation.

    PubMed

    Ciricillo, S P; Hill, M P; Gonzalez, M F; Smalley, S; Morton, M T; Sharp, F R

    1994-04-01

    Local cerebral glucose utilization was assessed during whisker stimulation by 2-deoxyglucose autoradiography. Whisker stimulation increased local cerebral glucose utilization in brainstem, thalamus and whisker sensory cortex in normal rats. Whereas whisker stimulation increased glucose metabolism in brainstem, whisker stimulation failed to increase glucose metabolism in thalamus of rats that had whisker sensory cortex ablated 5 h to five weeks previously. The failure of whisker stimulation to activate thalamus after cortical ablations was probably not due to decreased cortical input to thalamus because whisker stimulation activated thalamus after large cortical tetrodotoxin injections. Failure of whisker stimulation to activate thalamus at early times (5 h and one day) after cortical ablations was not due to thalamic neuronal death, since it takes days to weeks for axotomized thalamic neurons to die. The failure of whisker stimulation to activate thalamus at early times after cortical ablations was likely due to the failure of trigeminal brainstem neurons that project to thalamus to activate axotomized thalamic neurons. This might occur because of synaptic retraction, glial stripping or inhibition of trigeminal brainstem synapses onto thalamic neurons. The thalamic neuronal death that occurs over the days and weeks following cortical ablations was associated with thalamic hypometabolism. This is consistent with the idea that the thalamic neurons die because of the absence of a cortically derived trophic factor, since the excitotoxic thalamic cell death that occurs following cortical kainate injections is associated with thalamic hypermetabolism. The glucose metabolism of parts of the host thalamus was higher and the glucose metabolism in surrounding nuclei lower than the normal side of thalamus in rats that sat quietly and had fetal cortex transplants placed into cavities in whisker sensory cortex five to 16 weeks previously. Whisker stimulation in these subjects

  1. Sparse and powerful cortical spikes.

    PubMed

    Wolfe, Jason; Houweling, Arthur R; Brecht, Michael

    2010-06-01

    Activity in cortical networks is heterogeneous, sparse and often precisely timed. The functional significance of sparseness and precise spike timing is debated, but our understanding of the developmental and synaptic mechanisms that shape neuronal discharge patterns has improved. Evidence for highly specialized, selective and abstract cortical response properties is accumulating. Singe-cell stimulation experiments demonstrate a high sensitivity of cortical networks to the action potentials of some, but not all, single neurons. It is unclear how this sensitivity of cortical networks to small perturbations comes about and whether it is a generic property of cortex. The unforeseen sensitivity to cortical spikes puts serious constraints on the nature of neural coding schemes.

  2. Locus coeruleus stimulation recruits a broad cortical neuronal network and increases cortical perfusion.

    PubMed

    Toussay, Xavier; Basu, Kaustuv; Lacoste, Baptiste; Hamel, Edith

    2013-02-20

    The locus coeruleus (LC), the main source of brain noradrenalin (NA), modulates cortical activity, cerebral blood flow (CBF), glucose metabolism, and blood-brain barrier permeability. However, the role of the LC-NA system in the regulation of cortical CBF has remained elusive. This rat study shows that similar proportions (∼20%) of cortical pyramidal cells and GABA interneurons are contacted by LC-NA afferents on their cell soma or proximal dendrites. LC stimulation induced ipsilateral activation (c-Fos upregulation) of pyramidal cells and of a larger proportion (>36%) of interneurons that colocalize parvalbumin, somatostatin, or nitric oxide synthase compared with pyramidal cells expressing cyclooxygenase-2 (22%, p < 0.05) or vasoactive intestinal polypeptide-containing interneurons (16%, p < 0.01). Concurrently, LC stimulation elicited larger ipsilateral compared with contralateral increases in cortical CBF (52 vs 31%, p < 0.01). These CBF responses were almost abolished (-70%, p < 0.001) by cortical NA denervation with DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride] and were significantly reduced by α- and β-adrenoceptor antagonists (-40%, p < 0.001 and -30%, p < 0.05, respectively). Blockade of glutamatergic or GABAergic neurotransmission with NMDA or GABA(A) receptor antagonists potently reduced the LC-induced hyperemic response (-56%, p < 0.001 or -47%, p < 0.05). Moreover, inhibition of astroglial metabolism (-35%, p < 0.01), vasoactive epoxyeicosatrienoic acids (EETs; -60%, p < 0.001) synthesis, large-conductance, calcium-operated (BK, -52%, p < 0.05), and inward-rectifier (Kir, -40%, p < 0.05) K+ channels primarily impaired the hyperemic response. The data demonstrate that LC stimulation recruits a broad network of cortical excitatory and inhibitory neurons resulting in increased cortical activity and that K+ fluxes and EET signaling mediate a large part of the hemodynamic response.

  3. Purely Cortical Anaplastic Ependymoma

    PubMed Central

    Romero, Flávio Ramalho; Zanini, Marco Antônio; Ducati, Luis Gustavo; Vital, Roberto Bezerra; de Lima Neto, Newton Moreira; Gabarra, Roberto Colichio

    2012-01-01

    Ependymomas are glial tumors derived from ependymal cells lining the ventricles and the central canal of the spinal cord. It may occur outside the ventricular structures, representing the extraventicular form, or without any relationship of ventricular system, called ectopic ependymona. Less than fifteen cases of ectopic ependymomas were reported and less than five were anaplastic. We report a rare case of pure cortical ectopic anaplastic ependymoma. PMID:23119204

  4. Lineage-specific laminar organization of cortical GABAergic interneurons.

    PubMed

    Ciceri, Gabriele; Dehorter, Nathalie; Sols, Ignasi; Huang, Z Josh; Maravall, Miguel; Marín, Oscar

    2013-09-01

    In the cerebral cortex, pyramidal cells and interneurons are generated in distant germinal zones, and so the mechanisms that control their precise assembly into specific microcircuits remain an enigma. Here we report that cortical interneurons labeled at the clonal level do not distribute randomly but rather have a strong tendency to cluster in the mouse neocortex. This behavior is common to different classes of interneurons, independently of their origin. Interneuron clusters are typically contained within one or two adjacent cortical layers, are largely formed by isochronically generated neurons and populate specific layers, as revealed by unbiased hierarchical clustering methods. Our results suggest that different progenitor cells give rise to interneurons populating infra- and supragranular cortical layers, which challenges current views of cortical neurogenesis. Thus, specific lineages of cortical interneurons seem to be produced to primarily mirror the laminar structure of the cerebral cortex, rather than its columnar organization.

  5. Posterior Cortical Atrophy

    PubMed Central

    Crutch, Sebastian J; Lehmann, Manja; Schott, Jonathan M; Rabinovici, Gil D; Rossor, Martin N; Fox, Nick C

    2013-01-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome that is characterized by a progressive decline in visuospatial, visuoperceptual, literacy and praxic skills. The progressive neurodegeneration affecting parietal, occipital and occipito-temporal cortices which underlies PCA is attributable to Alzheimer's disease (AD) in the majority of patients. However, alternative underlying aetiologies including Dementia with Lewy Bodies (DLB), corticobasal degeneration (CBD) and prion disease have also been identified, and not all PCA patients have atrophy on clinical imaging. This heterogeneity has led to diagnostic and terminological inconsistencies, caused difficulty comparing studies from different centres, and limited the generalizability of clinical trials and investigations of factors driving phenotypic variability. Significant challenges remain in identifying the factors associated with both the selective vulnerability of posterior cortical regions and the young age of onset seen in PCA. Greater awareness of the syndrome and agreement over the correspondence between syndrome-and disease-level classifications are required in order to improve diagnostic accuracy, research study design and clinical management. PMID:22265212

  6. Adult Visual Cortical Plasticity

    PubMed Central

    Gilbert, Charles D.; Li, Wu

    2012-01-01

    The visual cortex has the capacity for experience dependent change, or cortical plasticity, that is retained throughout life. Plasticity is invoked for encoding information during perceptual learning, by internally representing the regularities of the visual environment, which is useful for facilitating intermediate level vision - contour integration and surface segmentation. The same mechanisms have adaptive value for functional recovery after CNS damage, such as that associated with stroke or neurodegenerative disease. A common feature to plasticity in primary visual cortex (V1) is an association field that links contour elements across the visual field. The circuitry underlying the association field includes a plexus of long range horizontal connections formed by cortical pyramidal cells. These connections undergo rapid and exuberant sprouting and pruning in response to removal of sensory input, which can account for the topographic reorganization following retinal lesions. Similar alterations in cortical circuitry may be involved in perceptual learning, and the changes observed in V1 may be representative of how learned information is encoded throughout the cerebral cortex. PMID:22841310

  7. Reconstructing cortical current density by exploring sparseness in the transform domain.

    PubMed

    Ding, Lei

    2009-05-07

    In the present study, we have developed a novel electromagnetic source imaging approach to reconstruct extended cortical sources by means of cortical current density (CCD) modeling and a novel EEG imaging algorithm which explores sparseness in cortical source representations through the use of L1-norm in objective functions. The new sparse cortical current density (SCCD) imaging algorithm is unique since it reconstructs cortical sources by attaining sparseness in a transform domain (the variation map of cortical source distributions). While large variations are expected to occur along boundaries (sparseness) between active and inactive cortical regions, cortical sources can be reconstructed and their spatial extents can be estimated by locating these boundaries. We studied the SCCD algorithm using numerous simulations to investigate its capability in reconstructing cortical sources with different extents and in reconstructing multiple cortical sources with different extent contrasts. The SCCD algorithm was compared with two L2-norm solutions, i.e. weighted minimum norm estimate (wMNE) and cortical LORETA. Our simulation data from the comparison study show that the proposed sparse source imaging algorithm is able to accurately and efficiently recover extended cortical sources and is promising to provide high-accuracy estimation of cortical source extents.

  8. Cortical Clefts and Cortical Bumps: A Continuous Spectrum

    PubMed Central

    Furruqh, Farha; Thirunavukarasu, Suresh; Vivekandan, Ravichandran

    2016-01-01

    Cortical ‘clefts’ (schizencephaly) and cortical ‘bumps’ (polymicrogyria) are malformations arising due to defects in postmigrational development of neurons. They are frequently encountered together, with schizencephalic clefts being lined by polymicrogyria. We present the case of an eight-year-old boy who presented with seizures. Imaging revealed closed lip schizencephaly, polymicrogyria and a deep ‘incomplete’ cleft lined by polymicrogyria not communicating with the lateral ventricle. We speculate that hypoperfusion or ischaemic cortical injury during neuronal development may lead to a spectrum of malformations ranging from polymicrogyria to incomplete cortical clefts to schizencephaly. PMID:27630923

  9. Early development of synchrony in cortical activations in the human

    PubMed Central

    Koolen, N.; Dereymaeker, A.; Räsänen, O.; Jansen, K.; Vervisch, J.; Matic, V.; Naulaers, G.; De Vos, M.; Van Huffel, S.; Vanhatalo, S.

    2016-01-01

    Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 and 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant increase in ASI in all cortical areas. Second, there were significant spatial gradients in the synchrony in fronto-occipital and left-to-right directions. These findings provide evidence that early cortical activity is increasingly synchronized across the neocortex. The ASI-based metrics introduced in our work allow direct translational comparison to in vivo animal models, as well as hold promise for implementation as a functional developmental biomarker in future research on human neonates. PMID:26876605

  10. Massive cortical reorganization in sighted Braille readers.

    PubMed

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-03-15

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills.

  11. Cortical forces in cell shape changes and tissue morphogenesis.

    PubMed

    Rauzi, Matteo; Lenne, Pierre-François

    2011-01-01

    Cortical forces drive a variety of cell shape changes and cell movements during tissue morphogenesis. While the molecular components underlying these forces have been largely identified, how they assemble and spatially and temporally organize at cell surfaces to promote cell shape changes in developing tissues are open questions. We present here different key aspects of cortical forces: their physical nature, some rules governing their emergence, and how their deployment at cell surfaces drives important morphogenetic movements in epithelia. We review a wide range of literature combining genetic/molecular, biophysical and modeling approaches, which explore essential features of cortical force generation and transmission in tissues.

  12. Cortical spreading depression: An enigma

    NASA Astrophysics Data System (ADS)

    Miura, R. M.; Huang, H.; Wylie, J. J.

    2007-08-01

    The brain is a complex organ with active components composed largely of neurons, glial cells, and blood vessels. There exists an enormous experimental and theoretical literature on the mechanisms involved in the functioning of the brain, but we still do not have a good understanding of how it works on a gross mechanistic level. In general, the brain maintains a homeostatic state with relatively small ion concentration changes, the major ions being sodium, potassium, and chloride. Calcium ions are present in smaller quantities but still play an important role in many phenomena. Cortical spreading depression (CSD for short) was discovered over 60 years ago by A.A.P. Leão, a Brazilian physiologist doing his doctoral research on epilepsy at Harvard University, “Spreading depression of activity in the cerebral cortex," J. Neurophysiol., 7 (1944), pp. 359-390. Cortical spreading depression is characterized by massive changes in ionic concentrations and slow nonlinear chemical waves, with speeds on the order of mm/min, in the cortex of different brain structures in various experimental animals. In humans, CSD is associated with migraine with aura, where a light scintillation in the visual field propagates, then disappears, and is followed by a sustained headache. To date, CSD remains an enigma, and further detailed experimental and theoretical investigations are needed to develop a comprehensive picture of the diverse mechanisms involved in producing CSD. A number of mechanisms have been hypothesized to be important for CSD wave propagation. In this paper, we briefly describe several characteristics of CSD wave propagation, and examine some of the mechanisms that are believed to be important, including ion diffusion, membrane ionic currents, osmotic effects, spatial buffering, neurotransmitter substances, gap junctions, metabolic pumps, and synaptic connections. Continuum models of CSD, consisting of coupled nonlinear diffusion equations for the ion concentrations, and

  13. Cortical spreading depression occurs during elective neurosurgical procedures.

    PubMed

    Carlson, Andrew P; William Shuttleworth, C; Mead, Brittany; Burlbaw, Brittany; Krasberg, Mark; Yonas, Howard

    2017-01-01

    OBJECTIVE Cortical spreading depression (CSD) has been observed with relatively high frequency in the period following human brain injury, including traumatic brain injury and ischemic/hemorrhagic stroke. These events are characterized by loss of ionic gradients through massive cellular depolarization, neuronal dysfunction (depression of electrocorticographic [ECoG] activity) and slow spread (2-5 mm/min) across the cortical surface. Previous data obtained in animals have suggested that even in the absence of underlying injury, neurosurgical manipulation can induce CSD and could potentially be a modifiable factor in neurosurgical injury. The authors report their initial experience with direct intraoperative ECoG monitoring for CSD. METHODS The authors prospectively enrolled patients undergoing elective craniotomy for supratentorial lesions in cases in which the surgical procedure was expected to last > 2 hours. These patients were monitored for CSD from the time of dural opening through the time of dural closure, using a standard 1 × 6 platinum electrode coupled with an AC or full-spectrum DC amplifier. The data were processed using standard techniques to evaluate for slow potential changes coupled with suppression of high-frequency ECoG propagating across the electrodes. Data were compared with CSD validated in previous intensive care unit (ICU) studies, to evaluate recording conditions most likely to permit CSD detection, and identify likely events during the course of neurosurgical procedures using standard criteria. RESULTS Eleven patients underwent ECoG monitoring during elective neurosurgical procedures. During the periods of monitoring, 2 definite CSDs were observed to occur in 1 patient and 8 suspicious events were detected in 4 patients. In other patients, either no events were observed or artifact limited interpretation of the data. The DC-coupled amplifier system represented an improvement in stability of data compared with AC-coupled systems. Compared

  14. Cortical-Cortical Interactions And Sensory Information Processing in Autism

    DTIC Science & Technology

    2008-04-30

    Additionally, these cortical areas have been implicated from significantly elevated TOJ thresholds (worse performance) in subjects with dyslexia [5...of the fact that above-average TOJ thresholds occur in subjects with known damage to these same cortical areas ( dyslexia [5], dystonia [6-8], and

  15. Effects of avoiding neuromuscular blocking agents during maintenance of anaesthesia on recovery characteristics in patients undergoing craniotomy for supratentorial lesions: A randomised controlled study

    PubMed Central

    Jain, Ruchi A; Shetty, Anita N; Oak, Shrikanta P; Wajekar, Anjana S; Garasia, Madhu B

    2017-01-01

    Background and Aims: Neuromuscular blocking agents have been one of the cornerstones of anaesthesia. With the advent of newer surgical, anaesthetic and neurological monitoring techniques, their utility in neuroanaesthesia practice seems dispensable. The aim of this prospective, comparative, randomised study was to determine whether neuromuscular blocking agents are required in patients undergoing supratentorial surgery when balanced anaesthesia with desflurane, dexmedetomidine and scalp block is used. Methods: Sixty patients with the American Society of Anesthesiologists physical status I or II, aged between 18 and 60 years were included in the study. All patients received anaesthesia including desflurane, dexmedetomidine and scalp block. The patients were randomly allocated to receive no neuromuscular blocking agent (Group A) or atracurium infusion to keep train-of-four count 2 (Group B). The two groups were compared with respect to haemodynamic stability, brain relaxation scores and recovery characteristics. Haemodynamic parameters and time taken to achieve Aldrete score >9 and other secondary outcomes were analysed using Student's t-test. Non-parametric data were analysed using the Mann–Whitney test. Results: The mean arterial pressure was comparable between the groups. The intraoperative heart rate was comparable; however, in the post-operative period, it remained higher in Group B for 30 min after extubation (P = 0.02). The brain relaxation scores were comparable among the two groups (P = 0.27). Tracheal extubation time, time taken for orientation and time required to reach Aldrete score ≥9 were comparable among the two groups. Conclusion: The present study suggests that balanced anaesthesia using desflurane, dexmedetomidine and scalp block can preclude the use of neuromuscular blocking agents in patients undergoing supratentorial surgery under intense haemodynamic monitoring. PMID:28216703

  16. Effects of an alveolar recruitment maneuver on subdural pressure, brain swelling, and mean arterial pressure in patients undergoing supratentorial tumour resection: a randomized crossover study.

    PubMed

    Flexman, Alana M; Gooderham, Peter A; Griesdale, Donald E; Argue, Ruth; Toyota, Brian

    2017-06-01

    Although recruitment maneuvers have been advocated as part of a lung protective ventilation strategy, their effects on cerebral physiology during elective neurosurgery are unknown. Our objectives were to determine the effects of an alveolar recruitment maneuver on subdural pressure (SDP), brain relaxation score (BRS), and cerebral perfusion pressure among patients undergoing supratentorial tumour resection. In this prospective crossover study, patients scheduled for resection of a supratentorial brain tumour were randomized to undergo either a recruitment maneuver (30 cm of water for 30 sec) or a "sham" maneuver (5 cm of water for 30 sec), followed by the alternative intervention after a 90-sec equilibration period. Subdural pressure was measured through a dural perforation following opening of the cranium. Subdural pressure and mean arterial pressure (MAP) were recorded continuously. The blinded neurosurgeon provided a BRS at baseline and at the end of each intervention. During each treatment, the changes in SDP, BRS, and MAP were compared. Twenty-one patients underwent the study procedure. The increase in SDP was higher during the recruitment maneuver than during the sham maneuver (difference, 3.9 mmHg; 95% confidence interval [CI], 2.2 to 5.6; P < 0.001). Mean arterial pressure decreased further in the recruitment maneuver than in the sham maneuver (difference, -9.0 mmHg; 95% CI, -12.5 to -5.6; P < 0.001). Cerebral perfusion pressure decreased 14 mmHg (95% CI, 4 to 24) during the recruitment maneuver. The BRS did not change with either maneuver. Our results suggest that recruitment maneuvers increase subdural pressure and reduce cerebral perfusion pressure, although the clinical importance of these findings is thus far unknown. This trial was registered with ClinicalTrials.gov, NCT02093117.

  17. Cortical Control of Zona Incerta

    PubMed Central

    Barthó, Péter; Slézia, Andrea; Varga, Viktor; Bokor, Hajnalka; Pinault, Didier; Buzsáki, György; Acsády, László

    2009-01-01

    The zona incerta (ZI) is at the crossroad of almost all major ascending and descending fiber tracts and targets numerous brain centers from the thalamus to the spinal cord. Effective ascending drive of ZI cells has been described, but the role of descending cortical signals in patterning ZI activity is unknown. Cortical control over ZI function was examined during slow cortical waves (1-3 Hz), paroxysmal high-voltage spindles (HVSs), and 5-9 Hz oscillations in anesthetized rats. In all conditions, rhythmic cortical activity significantly altered the firing pattern of ZI neurons recorded extracellularly and labeled with the juxtacellular method. During slow oscillations, the majority of ZI neurons became synchronized to the depth-negative phase (“up state”) of the cortical waves to a degree comparable to thalamocortical neurons. During HVSs, ZI cells displayed highly rhythmic activity in tight synchrony with the cortical oscillations. ZI neurons responded to short epochs of cortical 5-9 Hz oscillations, with a change in the interspike interval distribution and with an increase in spectral density in the 5-9 Hz band as measured by wavelet analysis. Morphological reconstruction revealed that most ZI cells have mediolaterally extensive dendritic trees and very long dendritic segments. Cortical terminals established asymmetrical synapses on ZI cells with very long active zones. These data suggest efficient integration of widespread cortical signals by single ZI neurons and strong cortical drive. We propose that the efferent GABAergic signal of ZI neurons patterned by the cortical activity can play a critical role in synchronizing thalamocortical and brainstem rhythms. PMID:17301175

  18. Mapping cortical mesoscopic networks of single spiking cortical or sub-cortical neurons

    PubMed Central

    Xiao, Dongsheng; Vanni, Matthieu P; Mitelut, Catalin C; Chan, Allen W; LeDue, Jeffrey M; Xie, Yicheng; Chen, Andrew CN; Swindale, Nicholas V; Murphy, Timothy H

    2017-01-01

    Understanding the basis of brain function requires knowledge of cortical operations over wide-spatial scales, but also within the context of single neurons. In vivo, wide-field GCaMP imaging and sub-cortical/cortical cellular electrophysiology were used in mice to investigate relationships between spontaneous single neuron spiking and mesoscopic cortical activity. We make use of a rich set of cortical activity motifs that are present in spontaneous activity in anesthetized and awake animals. A mesoscale spike-triggered averaging procedure allowed the identification of motifs that are preferentially linked to individual spiking neurons by employing genetically targeted indicators of neuronal activity. Thalamic neurons predicted and reported specific cycles of wide-scale cortical inhibition/excitation. In contrast, spike-triggered maps derived from single cortical neurons yielded spatio-temporal maps expected for regional cortical consensus function. This approach can define network relationships between any point source of neuronal spiking and mesoscale cortical maps. DOI: http://dx.doi.org/10.7554/eLife.19976.001 PMID:28160463

  19. Evaluating mandibular cortical index quantitatively.

    PubMed

    Yasar, Fusun; Akgunlu, Faruk

    2008-10-01

    The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.

  20. Evaluating Mandibular Cortical Index Quantitatively

    PubMed Central

    Yasar, Fusun; Akgunlu, Faruk

    2008-01-01

    Objectives The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Methods Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718–0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. Results It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). Conclusions FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs. PMID:19212535

  1. Cortical Development and Neuroplasticity in Auditory Neuropathy Spectrum Disorder

    PubMed Central

    Sharma, Anu; Cardon, Garrett

    2015-01-01

    Cortical development is dependent to a large extent on stimulus-driven input. Auditory Neuropathy Spectrum Disorder (ANSD) is a recently described form of hearing impairment where neural dys-synchrony is the predominant characteristic. Children with ANSD provide a unique platform to examine the effects of asynchronous and degraded afferent stimulation on cortical auditory neuroplasticity and behavioral processing of sound. In this review, we describe patterns of auditory cortical maturation in children with ANSD. The disruption of cortical maturation that leads to these various patterns includes high levels of intra-individual cortical variability and deficits in cortical phase synchronization of oscillatory neural responses. These neurodevelopmental changes, which are constrained by sensitive periods for central auditory maturation, are correlated with behavioral outcomes for children with ANSD. Overall, we hypothesize that patterns of cortical development in children with ANSD appear to be markers of the severity of the underlying neural dys-synchrony, providing prognostic indicators of success of clinical intervention with amplification and/or electrical stimulation. PMID:26070426

  2. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy

    PubMed Central

    Kaski, Diego; Yong, Keir X. X.; Paterson, Ross W.; Slattery, Catherine F.; Ryan, Natalie S.; Schott, Jonathan M.; Crutch, Sebastian J.

    2015-01-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal ‘visual dementia’ and most common atypical Alzheimer’s disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients’ (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer’s disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer’s disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer’s disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with ‘sticky fixation’. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer’s disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large

  3. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    PubMed

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions

  4. Modeling cortical circuits.

    SciTech Connect

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  5. Paroxysmal kinesigenic dyskinesia: cortical or non-cortical origin.

    PubMed

    van Strien, Teun W; van Rootselaar, Anne-Fleur; Hilgevoord, Anthony A J; Linssen, Wim H J P; Groffen, Alexander J A; Tijssen, Marina A J

    2012-06-01

    Paroxysmal kinesigenic dyskinesia (PKD) is characterized by involuntary dystonia and/or chorea triggered by a sudden movement. Cases are usually familial with an autosomal dominant inheritance. Hypotheses regarding the pathogenesis of PKD focus on the controversy whether PKD has a cortical or non-cortical origin. A combined familial trait of PKD and benign familial infantile seizures has been reported as the infantile convulsions and paroxysmal choreoathetosis (ICCA) syndrome. Here, we report a family diagnosed with ICCA syndrome with an Arg217STOP mutation. The index patient showed interictal EEG focal changes compatible with paroxysmal dystonic movements of his contralateral leg. This might support cortical involvement in PKD.

  6. Developmental cortical thinning in fetal alcohol spectrum disorders.

    PubMed

    Zhou, Dongming; Lebel, Catherine; Lepage, Claude; Rasmussen, Carmen; Evans, Alan; Wyper, Katy; Pei, Jacqueline; Andrew, Gail; Massey, Ashleigh; Massey, Donald; Beaulieu, Christian

    2011-09-01

    Regional cortical thickness was evaluated using CIVET processing of 3D T1-weighted images (i) to compare the variation in cortical thickness between 33 participants with fetal alcohol spectrum disorders (FASD) aged 6-30 years (mean age 12.3 years) versus 33 age/sex/hand-matched controls, and (ii) to examine developmental changes in cortical thickness with age from children to young adults in both groups. Significant cortical thinning was found in the participants with FASD in large areas of the bilateral middle frontal lobe, pre- and post- central areas, lateral and inferior temporal and occipital lobes compared to controls. No significant cortical thickness increases were observed for the FASD group. Cortical thinning with age in a linear model was observed in both groups, but the locations were different for each group. FASD participants showed thinning with age in the left middle frontal, bilateral precentral, bilateral precuneus and paracingulate, left inferior occipital and bilateral fusiform gyri; while controls showed decreases with age in the bilateral middle frontal gyrus, right inferior frontal gyrus, bilateral precuneus gyrus, and bilateral occipital gyrus. A battery of cognitive assessments of memory, attention, motor, and verbal abilities was conducted with many of the FASD participants, but no significant correlations were found between these cognitive scores and regional cortical thickness. Non-invasive measurements of cortical thickness in children to young adults with FASD have identified both key regions of cortex that may be more deleteriously affected by prenatal alcohol exposure as well as cortical changes with age that differ from normal developmental thinning. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Cortical Magnification Plus Cortical Plasticity Equals Vision?

    PubMed Central

    Born, Richard T.; Trott, Alexander; Hartmann, Till

    2014-01-01

    Most approaches to visual prostheses have focused on the retina, and for good reasons. The earlier that one introduces signals into the visual system, the more one can take advantage of its prodigious computational abilities. For methods that make use of microelectrodes to introduce electrical signals, however, the limited density and volume occupying nature of the electrodes place severe limits on the image resolution that can be provided to the brain. In this regard, non-retinal areas in general, and the primary visual cortex in particular, possess one large advantage: “magnification factor” (MF)—a value that represents the distance across a sheet of neurons that represents a given angle of the visual field. In the foveal representation of primate primary visual cortex, the MF is enormous—on the order of 15–20 mm/deg in monkeys and humans, whereas on the retina, the MF is limited by the optical design of the eye to around 0.3 mm/deg. This means that, for an electrode array of a given density, a much higher- resolution image can be introduced into V1 than onto the retina (or any other visual structure). In addition to this tremendous advantage in resolution, visual cortex is plastic at many different levels ranging from a very local ability to learn to better detect electrical stimulation to higher levels of learning that permit human observers to adapt to radical changes to their visual inputs. We argue that the combination of the large magnification factor and the impressive ability of the cerebral cortex to learn to recognize arbitrary patterns, might outweigh the disadvantages of bypassing earlier processing stages and makes V1 a viable option for the restoration of vision. PMID:25449335

  8. Cholinergic Neurons Excite Cortically Projecting Basal Forebrain GABAergic Neurons

    PubMed Central

    Yang, Chun; McKenna, James T.; Zant, Janneke C.; Winston, Stuart; Basheer, Radhika

    2014-01-01

    The basal forebrain (BF) plays an important role in the control of cortical activation and attention. Understanding the modulation of BF neuronal activity is a prerequisite to treat disorders of cortical activation involving BF dysfunction, such as Alzheimer's disease. Here we reveal the interaction between cholinergic neurons and cortically projecting BF GABAergic neurons using immunohistochemistry and whole-cell recordings in vitro. In GAD67-GFP knock-in mice, BF cholinergic (choline acetyltransferase-positive) neurons were intermingled with GABAergic (GFP+) neurons. Immunohistochemistry for the vesicular acetylcholine transporter showed that cholinergic fibers apposed putative cortically projecting GABAergic neurons containing parvalbumin (PV). In coronal BF slices from GAD67-GFP knock-in or PV-tdTomato mice, pharmacological activation of cholinergic receptors with bath application of carbachol increased the firing rate of large (>20 μm diameter) BF GFP+ and PV (tdTomato+) neurons, which exhibited the intrinsic membrane properties of cortically projecting neurons. The excitatory effect of carbachol was blocked by antagonists of M1 and M3 muscarinic receptors in two subpopulations of BF GABAergic neurons [large hyperpolarization-activated cation current (Ih) and small Ih, respectively]. Ion substitution experiments and reversal potential measurements suggested that the carbachol-induced inward current was mediated mainly by sodium-permeable cation channels. Carbachol also increased the frequency of spontaneous excitatory and inhibitory synaptic currents. Furthermore, optogenetic stimulation of cholinergic neurons/fibers caused a mecamylamine- and atropine-sensitive inward current in putative GABAergic neurons. Thus, cortically projecting, BF GABAergic/PV neurons are excited by neighboring BF and/or brainstem cholinergic neurons. Loss of cholinergic neurons in Alzheimer's disease may impair cortical activation, in part, through disfacilitation of BF cortically

  9. Cognitive Plasticity and Cortical Modules.

    PubMed

    Mercado, Eduardo

    2009-06-01

    Some organisms learn to calculate, accumulate knowledge, and communicate in ways that others do not. What factors determine which intellectual abilities a particular species or individual can easily acquire? I propose that cognitive-skill learning capacity reflects (a) the availability of specialized cortical circuits, (b) the flexibility with which cortical activity is coordinated, and (c) the customizability of cortical networks. This framework can potentially account for differences in learning capacity across species, individuals, and developmental stages. Understanding the mechanisms that constrain cognitive plasticity is fundamental to developing new technologies and educational practices that maximize intellectual advancements.

  10. Cognitive Plasticity and Cortical Modules

    PubMed Central

    Mercado, Eduardo

    2009-01-01

    Some organisms learn to calculate, accumulate knowledge, and communicate in ways that others do not. What factors determine which intellectual abilities a particular species or individual can easily acquire? I propose that cognitive-skill learning capacity reflects (a) the availability of specialized cortical circuits, (b) the flexibility with which cortical activity is coordinated, and (c) the customizability of cortical networks. This framework can potentially account for differences in learning capacity across species, individuals, and developmental stages. Understanding the mechanisms that constrain cognitive plasticity is fundamental to developing new technologies and educational practices that maximize intellectual advancements. PMID:19750239

  11. Partial volume correction using cortical surfaces

    NASA Astrophysics Data System (ADS)

    Blaasvær, Kamille R.; Haubro, Camilla D.; Eskildsen, Simon F.; Borghammer, Per; Otzen, Daniel; Ostergaard, Lasse R.

    2010-03-01

    Partial volume effect (PVE) in positron emission tomography (PET) leads to inaccurate estimation of regional metabolic activities among neighbouring tissues with different tracer concentration. This may be one of the main limiting factors in the utilization of PET in clinical practice. Partial volume correction (PVC) methods have been widely studied to address this issue. MRI based PVC methods are well-established.1 Their performance depend on the quality of the co-registration of the MR and PET dataset, on the correctness of the estimated point-spread function (PSF) of the PET scanner and largely on the performance of the segmentation method that divide the brain into brain tissue compartments.1, 2 In the present study a method for PVC is suggested, that utilizes cortical surfaces, to obtain detailed anatomical information. The objectives are to improve the performance of PVC, facilitate a study of the relationship between metabolic activity in the cerebral cortex and cortical thicknesses, and to obtain an improved visualization of PET data. The gray matter metabolic activity after performing PVC was recovered by 99.7 - 99.8 % , in relation to the true activity when testing on simple simulated data with different PSFs and by 97.9 - 100 % when testing on simulated brain PET data at different cortical thicknesses. When studying the relationship between metabolic activities and anatomical structures it was shown on simulated brain PET data, that it is important to correct for PVE in order to get the true relationship.

  12. Demixing Population Activity in Higher Cortical Areas

    PubMed Central

    Machens, Christian K.

    2009-01-01

    Neural responses in higher cortical areas often display a baffling complexity. In animals performing behavioral tasks, single neurons will typically encode several parameters simultaneously, such as stimuli, rewards, decisions, etc. When dealing with this large heterogeneity of responses, cells are conventionally classified into separate response categories using various statistical tools. However, this classical approach usually fails to account for the distributed nature of representations in higher cortical areas. Alternatively, principal component analysis (PCA) or related techniques can be employed to reduce the complexity of a data set while retaining the distributional aspect of the population activity. These methods, however, fail to explicitly extract the task parameters from the neural responses. Here we suggest a coordinate transformation that seeks to ameliorate these problems by combining the advantages of both methods. Our basic insight is that variance in neural firing rates can have different origins (such as changes in a stimulus, a reward, or the passage of time), and that, instead of lumping them together, as PCA does, we need to treat these sources separately. We present a method that seeks an orthogonal coordinate transformation such that the variance captured from different sources falls into orthogonal subspaces and is maximized within these subspaces. Using simulated examples, we show how this approach can be used to demix heterogeneous neural responses. Our method may help to lift the fog of response heterogeneity in higher cortical areas. PMID:21031029

  13. Experience dependent plasticity alters cortical synchronization

    PubMed Central

    Kilgard, M.P.; Vazquez, J.L.; Engineer, N.D.; Pandya, P.K.

    2008-01-01

    Theories of temporal coding by cortical neurons are supported by observations that individual neurons can respond to sensory stimulation with millisecond precision and that activity in large populations is often highly correlated. Synchronization is highest between neurons with overlapping receptive fields and modulated by both sensory stimulation and behavioral state. It is not yet clear whether cortical synchronization is an epiphenomenon or a critical component of efficient information transmission. Experimental manipulations that generate receptive field plasticity can be used to test the relationship between synchronization and receptive fields. Here we demonstrate that increasing receptive field size in primary auditory cortex by repeatedly pairing a train of tones with nucleus basalis (NB) stimulation increases synchronization, and decreasing receptive field size by pairing different tone frequencies with NB stimulation decreases synchronization. These observations seem to support the conclusion that neural synchronization is simply an artifact caused by common inputs. However, pairing tone trains of different carrier frequencies with NB stimulation increases receptive field size without increasing synchronization, and environmental enrichment increases synchronization without increasing receptive field size. The observation that receptive fields and synchronization can be manipulated independently suggests that common inputs are only one of many factors shaping the strength and temporal precision of cortical synchronization and supports the hypothesis that precise neural synchronization contributes to sensory information processing. PMID:17317055

  14. Motor cortical organization in an adult with hemimegalencephaly and late onset epilepsy.

    PubMed

    Civardi, Carlo; Vicentini, Roberta; Collini, Alessandra; Boccagni, Cristina; Cantello, Roberto; Monaco, Francesco

    2009-08-28

    Hemimegalencephaly is a rare brain malformation whose physiology is largely obscure. In a single patient, we studied motor cortex using several transcranial magnetic stimulation variables testing cortical excitability, and mapping motor area. The megalencephalic hemisphere showed an enlargement of cortical motor map with abnormal axonal orientation and an excess spread of corticospinal excitation, associated with multiple defects of cortical inhibition. TMS gave new information on the anatomic/functional features and epileptogenesis in this complex and physiologically obscure syndrome.

  15. CENTS: Cortical Enhanced Neonatal Tissue Segmentation

    PubMed Central

    Shi, Feng; Shen, Dinggang; Yap, Pew-Thian; Fan, Yong; Cheng, Jie-Zhi; An, Hongyu; Wald, Lawrence L.; Gerig, Guido; Gilmore, John H.; Lin, Weili

    2010-01-01

    The acquisition of high-quality magnetic resonance (MR) images of neonatal brains is largely hampered by their characteristically small head size and insufficient tissue contrast. As a result, subsequent image processing and analysis, especially brain tissue segmentation, are often affected. To overcome this problem, a dedicated phased array neonatal head coil is utilized to improve MR image quality by augmenting signal-to-noise ratio and spatial resolution without lengthening data acquisition time. In addition, a specialized hybrid atlas-based tissue segmentation algorithm is developed for the delineation of fine structures in the acquired neonatal brain MR images. The proposed tissue segmentation method first enhances the sheet-like cortical gray matter (GM) structures in the to-be-segmented neonatal image with a Hessian filter for generation of a cortical GM confidence map. A neonatal population atlas is then generated by averaging the presegmented images of a population, weighted by their cortical GM similarity with respect to the to-be-segmented image. Finally, the neonatal population atlas is combined with the GM confidence map, and the resulting enhanced tissue probability maps for each tissue form a hybrid atlas that is used for atlas-based segmentation. Various experiments are conducted to compare the segmentations of the proposed method with manual segmentation (on both images acquired with a dedicated phased array coil and a conventional volume coil), as well as with the segmentations of two population-atlas-based methods. Results show the proposed method is capable of segmenting the neonatal brain with the best accuracy, and also preserving the most structural details in the cortical regions. PMID:20690143

  16. Analysis of Cortical Flow Models In Vivo

    PubMed Central

    Benink, Hélène A.; Mandato, Craig A.; Bement, William M.

    2000-01-01

    Cortical flow, the directed movement of cortical F-actin and cortical organelles, is a basic cellular motility process. Microtubules are thought to somehow direct cortical flow, but whether they do so by stimulating or inhibiting contraction of the cortical actin cytoskeleton is the subject of debate. Treatment of Xenopus oocytes with phorbol 12-myristate 13-acetate (PMA) triggers cortical flow toward the animal pole of the oocyte; this flow is suppressed by microtubules. To determine how this suppression occurs and whether it can control the direction of cortical flow, oocytes were subjected to localized manipulation of either the contractile stimulus (PMA) or microtubules. Localized PMA application resulted in redirection of cortical flow toward the site of application, as judged by movement of cortical pigment granules, cortical F-actin, and cortical myosin-2A. Such redirected flow was accelerated by microtubule depolymerization, showing that the suppression of cortical flow by microtubules is independent of the direction of flow. Direct observation of cortical F-actin by time-lapse confocal analysis in combination with photobleaching showed that cortical flow is driven by contraction of the cortical F-actin network and that microtubules suppress this contraction. The oocyte germinal vesicle serves as a microtubule organizing center in Xenopus oocytes; experimental displacement of the germinal vesicle toward the animal pole resulted in localized flow away from the animal pole. The results show that 1) cortical flow is directed toward areas of localized contraction of the cortical F-actin cytoskeleton; 2) microtubules suppress cortical flow by inhibiting contraction of the cortical F-actin cytoskeleton; and 3) localized, microtubule-dependent suppression of actomyosin-based contraction can control the direction of cortical flow. We discuss these findings in light of current models of cortical flow. PMID:10930453

  17. The brain relaxation and cerebral metabolism in stroke volume variation-directed fluid therapy during supratentorial tumors resection: crystalloid solution versus colloid solution.

    PubMed

    Xia, Juan; He, Zhiyong; Cao, Xiaoying; Che, Xuehua; Chen, Liang; Zhang, Jun; Liang, Weimin

    2014-10-01

    Compared with goal-directed crystalloid therapy, goal-directed colloid therapy during high-risk surgery may improve postoperative outcome. Whether intraoperative fluid therapy based on goal-directed protocol with different types of fluid has distinctive effects on brain relaxation and cerebral metabolism during craniotomy remains unclear. Forty patients with supratentorial brain tumors undergoing craniotomy were randomly assigned to either a Ringer's Lactate-based goal-directed group (LR group, n=20) or a 6% hydroxyethyl starch-based goal-directed group (HES group, n=20). The goal was achieved by maintaining a target stroke volume variation (SVV<13%) by volume loading with LR or HES throughout the procedure. The primary outcome is brain relaxation scales, an indirect evaluation of ICP; secondary endpoints include cerebral metabolism variables (jugular venous oxygen saturation [SjvO(2)], arterial-jugular venous differences in oxygen [CajvO(2)], glucose [A-JvGD], lactate [A-JvLD], and cerebral extraction ratio for oxygen [CERO(2)]) and fluid volumes. There is no significant difference between the LR and HES groups on brain relaxation scales (P=0.845), or measures of cerebral oxygenation and metabolism. Intragroup comparisons showed that CERO(2) increased by 14.3% (P=0.009, LR group) and 13.2% (P=0.032, HES group), respectively, and SjvO(2) was decreased by 8.8% (P=0.016, LR group) and 8.1% (P=0.026, HES group), respectively, after tumor removal, compared with baseline. During surgery, the LR group (3070±1138 mL) received more fluid than the HES group (2041±758 mL, P=0.002). In patients undergoing supratentorial tumor resection, goal-directed HES therapy was not superior to goal-directed LR therapy for brain relaxation or cerebral metabolism, although less fluid was needed to maintain the target SVV in the HES-based group than in the LR-based group.

  18. No difference in emergence time and early cognitive function between sevoflurane-fentanyl and propofol-remifentanil in patients undergoing craniotomy for supratentorial intracranial surgery.

    PubMed

    Magni, G; Baisi, F; La Rosa, I; Imperiale, C; Fabbrini, V; Pennacchiotti, M L; Rosa, G

    2005-07-01

    Balanced anesthesia with sevoflurane-fentanyl has been widely accepted as anesthetic management for neurosurgery. Propofol-remifentanil regimen has been successfully used in various surgical settings, but a comprehensive comparison of sevoflurane-fentanyl and propofol-remifentanil anesthesia in patients undergoing craniotomy for supratentorial intracranial surgery has not yet been done. The aim of this prospective, randomized, open-label clinical trial was to compare clinical properties of sevoflurane-fentanyl with propofol-remifentanil anesthesia in patients undergoing supratentorial intracranial surgery. The primary endpoint was to compare early postoperative recovery and cognitive functions within the two groups; we also evaluated hemodynamic events, vomiting, shivering, and pain. One hundred twenty patients (64 males; age 15-75 years) were randomized to either total intravenous anesthesia (group T) or sevoflurane anesthesia (group S). Emergence and extubation times and cognitive function (Short Orientation Memory Concentration Test [SOMCT]) were compared in the two groups. Brain swelling, incidence of hypotensive and hypertensive episodes, postoperative vomiting, shivering, and pain were also analyzed. The mean emergence time (12.2 +/- 4.9 minutes for group S versus 12.3 +/- 6.1 minutes for group T; P = 0.92) and extubation time (18.2 +/- 2.3 minutes for group S versus 18.3 +/- 2.1 minutes for group T; P = 0.80) were similar in the two groups. Average SOMCT scores, both 15 minutes after extubation (25.6 +/- 4.9 in group S versus 23.9 +/- 7.5 in group T; P = 0.14) and 45 minutes after extubation (27.3 +/- 2.2 in group S versus 26.0 +/- 5.1 in group T; P = 0.07) were also comparable. Brain swelling was present in seven and five patients in groups S and T, respectively (P = 0.76). Hypotension was present in 12% (group S) and 28% (group T) of patients (P = 0.02). Hypertension was present in 17% of patients in group S and 40% of patients in group T (P = 0

  19. Somatostatin-Expressing Inhibitory Interneurons in Cortical Circuits

    PubMed Central

    Yavorska, Iryna; Wehr, Michael

    2016-01-01

    Cortical inhibitory neurons exhibit remarkable diversity in their morphology, connectivity, and synaptic properties. Here, we review the function of somatostatin-expressing (SOM) inhibitory interneurons, focusing largely on sensory cortex. SOM neurons also comprise a number of subpopulations that can be distinguished by their morphology, input and output connectivity, laminar location, firing properties, and expression of molecular markers. Several of these classes of SOM neurons show unique dynamics and characteristics, such as facilitating synapses, specific axonal projections, intralaminar input, and top-down modulation, which suggest possible computational roles. SOM cells can be differentially modulated by behavioral state depending on their class, sensory system, and behavioral paradigm. The functional effects of such modulation have been studied with optogenetic manipulation of SOM cells, which produces effects on learning and memory, task performance, and the integration of cortical activity. Different classes of SOM cells participate in distinct disinhibitory circuits with different inhibitory partners and in different cortical layers. Through these disinhibitory circuits, SOM cells help encode the behavioral relevance of sensory stimuli by regulating the activity of cortical neurons based on subcortical and intracortical modulatory input. Associative learning leads to long-term changes in the strength of connectivity of SOM cells with other neurons, often influencing the strength of inhibitory input they receive. Thus despite their heterogeneity and variability across cortical areas, current evidence shows that SOM neurons perform unique neural computations, forming not only distinct molecular but also functional subclasses of cortical inhibitory interneurons. PMID:27746722

  20. Consistent cortical reconstruction and multi-atlas brain segmentation.

    PubMed

    Huo, Yuankai; Plassard, Andrew J; Carass, Aaron; Resnick, Susan M; Pham, Dzung L; Prince, Jerry L; Landman, Bennett A

    2016-09-01

    Whole brain segmentation and cortical surface reconstruction are two essential techniques for investigating the human brain. Spatial inconsistences, which can hinder further integrated analyses of brain structure, can result due to these two tasks typically being conducted independently of each other. FreeSurfer obtains self-consistent whole brain segmentations and cortical surfaces. It starts with subcortical segmentation, then carries out cortical surface reconstruction, and ends with cortical segmentation and labeling. However, this "segmentation to surface to parcellation" strategy has shown limitations in various cohorts such as older populations with large ventricles. In this work, we propose a novel "multi-atlas segmentation to surface" method called Multi-atlas CRUISE (MaCRUISE), which achieves self-consistent whole brain segmentations and cortical surfaces by combining multi-atlas segmentation with the cortical reconstruction method CRUISE. A modification called MaCRUISE(+) is designed to perform well when white matter lesions are present. Comparing to the benchmarks CRUISE and FreeSurfer, the surface accuracy of MaCRUISE and MaCRUISE(+) is validated using two independent datasets with expertly placed cortical landmarks. A third independent dataset with expertly delineated volumetric labels is employed to compare segmentation performance. Finally, 200MR volumetric images from an older adult sample are used to assess the robustness of MaCRUISE and FreeSurfer. The advantages of MaCRUISE are: (1) MaCRUISE constructs self-consistent voxelwise segmentations and cortical surfaces, while MaCRUISE(+) is robust to white matter pathology. (2) MaCRUISE achieves more accurate whole brain segmentations than independently conducting the multi-atlas segmentation. (3) MaCRUISE is comparable in accuracy to FreeSurfer (when FreeSurfer does not exhibit global failures) while achieving greater robustness across an older adult population. MaCRUISE has been made freely

  1. Reduced Synaptic Vesicle Recycling during Hypoxia in Cultured Cortical Neurons

    PubMed Central

    Fedorovich, Sergei; Hofmeijer, Jeannette; van Putten, Michel J. A. M.; le Feber, Joost

    2017-01-01

    Improvement of neuronal recovery in the ischemic penumbra, an area around the core of a brain infarct with some remaining perfusion, has a large potential for the development of therapy against acute ischemic stroke. However, mechanisms that lead to either recovery or secondary damage in the penumbra largely remain unclear. Recent studies in cultured networks of cortical neurons showed that failure of synaptic transmission (referred to as synaptic failure) is a critical factor in the penumbral area, but the mechanisms that lead to synaptic failure are still under investigation. Here we used a Styryl dye, FM1-43, to quantify endocytosis and exocytosis in cultures of rat cortical neurons under normoxic and hypoxic conditions. Hypoxia in cultured cortical networks rapidly depressed endocytosis and, to a lesser extent, exocytosis. These findings support electrophysiological findings that synaptic failure occurs quickly after the induction of hypoxia, and confirms that the failing processes are at least in part presynaptic. PMID:28261063

  2. Orderly cortical representation of vowel categories presented by multiple exemplars.

    PubMed

    Shestakova, Anna; Brattico, Elvira; Soloviev, Alexei; Klucharev, Vasily; Huotilainen, Minna

    2004-11-01

    This study aimed at determining how the human brain automatically processes phoneme categories irrespective of the large acoustic inter-speaker variability. Subjects were presented with 450 different speech stimuli, equally distributed across the [a], [i], and [u] vowel categories, and each uttered by a different male speaker. A 306-channel magnetoencephalogram (MEG) was used to record N1m, the magnetic counterpart of the N1 component of the auditory event-related potential (ERP). The N1m amplitude and source locations differed between vowel categories. We also found that the spectrum dissimilarities were reproduced in the cortical representations of the large set of the phonemes used in this study: vowels with similar spectral envelopes had closer cortical representations than those whose spectral differences were the largest. Our data further extend the notion of differential cortical representations in response to vowel categories, previously demonstrated by using only one or a few tokens representing each category.

  3. Effect of Intrinsic and Extrinsic Factors on Global and Regional Cortical Thickness

    PubMed Central

    Govindarajan, Koushik A.; Freeman, Leorah; Cai, Chunyan; Rahbar, Mohammad H.; Narayana, Ponnada A.

    2014-01-01

    Global and regional cortical thicknesses based on T1-weighted magnetic resonance images acquired at 1.5 T and 3 T were measured on a relatively large cohort of 295 subjects using FreeSurfer software. Multivariate regression analysis was performed using Pillai's trace test to determine significant differences in cortical thicknesses measured at these two field strengths. Our results indicate that global cortical thickness is not affected by the field strength or gender. In contrast, the regional cortical thickness was observed to be field dependent. Specifically, the cortical thickness in regions such as parahippocampal, superior temporal, precentral and posterior cingulate is thicker at 3 T than at 1.5 T. In contrast regions such as cuneus and pericalcarine showed higher cortical thickness at 1.5 T than at 3 T. These differences appear to be age-dependent. The differences in regional cortical thickness between field strengths were similar in both genders. Further, male vs. female differences in regional cortical thickness were observed only at 1.5 T and not at 3 T. Our results indicate that magnetic field strength has a significant effect on the estimation of regional, but not global, cortical thickness. In addition, the pulse sequence, scanner type, and spatial resolution do not appear to have significant effect on the measured cortical thickness. PMID:24789100

  4. Three-tesla functional MR language mapping: comparison with direct cortical stimulation in gliomas.

    PubMed

    Kuchcinski, Grégory; Mellerio, Charles; Pallud, Johan; Dezamis, Edouard; Turc, Guillaume; Rigaux-Viodé, Odile; Malherbe, Caroline; Roca, Pauline; Leclerc, Xavier; Varlet, Pascale; Chrétien, Fabrice; Devaux, Bertrand; Meder, Jean-Francois; Oppenheim, Catherine

    2015-02-10

    To evaluate the accuracy of functional MRI (fMRI) at 3T, as currently used in the preoperative mapping of language areas, compared with direct cortical stimulation (DCS) during awake surgery, in patients with supratentorial gliomas; and to identify clinical, histopathologic,and radiologic factors associated with fMRI/DCS discrepancies. Language mapping with fMRI and DCS of 40 consecutive patients with gliomas(24 low-grade, 16 high-grade) in functional areas were retrospectively analyzed. Three block designed tasks were performed during fMRI (letter word generation, category word generation,semantic association). During awake surgery, eloquent areas were mapped using DCS, blinded to fMRI. A site-by-site comparison of the 2 techniques was performed using a cortical grid. fMRI sensitivity and specificity were calculated using DCS as the reference. Associations of clinical,histopathologic, and radiologic features (including relative cerebral blood volume [rCBV] measured with dynamic susceptibility contrast MRI) with fMRI false-positive and false-negative occurrence were assessed using hierarchical logistic regressions. Of 2,114 stimulated cortical sites, 103 were positive for language during DCS. Sensitivity and specificity of language fMRI combining the 3 tasks reached 37.1% (95% confidence interval [CI] 20.7–57.2) and 83.4% (95% CI 77.1–88.3), respectively. Astrocytoma subtype(odds ratio [OR] 2.50 [1.32–4.76]; p 5 0.007), tumor rCBV ,1.5 (OR 2.17 [1.08–4.35]; p 50.03), higher cortical rCBV (OR 2.22 [1.15–4.17]; p 5 0.02), and distance to tumor .1 cm (OR2.46 [1.82–3.32]; p # 0.001) were independently associated with fMRI false-positive occurrence. There are pitfalls in preoperative fMRI as currently used in preoperative language mapping in glioma patients, made more complicated when high-grade and hyperperfused tumors are evaluated.

  5. Effects of combining electroacupuncture with general anesthesia induced by sevoflurane in patients undergoing supratentorial craniotomy and improvements in their clinical recovery profile & blood enkephalin.

    PubMed

    Yang, Caixia; An, Lixin; Han, Ruquan; Kang, Xixiong; Wang, Baoguo

    2012-01-01

    Drug-induced anesthesia combined with electroacupuncture (EA) in patients has been put into practice in recent years in China. In this study, we showed the effectiveness of EA on the speed of post-operative recovery of patients undergoing supratentorial craniotomy and the potential clinical mechanism of EA. Dual channel electrical stimulator made by HANS Beijing connected the following acupoints respectively: LI4 (Hegu), SJ5 (Waiguan), ST36 (Zusanli), BL63 (Jinmen), LR3 (Taichong), and GB40 (Qiuxu). Disperse-dense and symmetric biphasic pulse waves were selected, frequency of waves (pulse rates) were 2Hz/100Hz, altered/3sec; pulse duration was 0.6ms/0.2ms, 2Hz: 0.6ms, 100Hz: 0.2ms; symmetric biphasic pulse wave. We found that the EA-group required 9.62% less sevoflurane than the sham EA-group (P<0.05). During recovery from anesthesia, the autonomous respiration recovery time, tracheo-tube removal time, eye-opening time, voluntary motor recovery time, orientation force recovery time, and the operating-room departure time of the EA-group were all significantly shortened 35.86%, 27.07%, 38.38%, 30.11%, 34.95%, 28.80% than the corresponding sham EA-group, respectively (P<0.05). The serum enkephalin values were elevated in the EA group versus the sham EA-group.

  6. Naive coadaptive cortical control.

    PubMed

    Gage, Gregory J; Ludwig, Kip A; Otto, Kevin J; Ionides, Edward L; Kipke, Daryl R

    2005-06-01

    The ability to control a prosthetic device directly from the neocortex has been demonstrated in rats, monkeys and humans. Here we investigate whether neural control can be accomplished in situations where (1) subjects have not received prior motor training to control the device (naive user) and (2) the neural encoding of movement parameters in the cortex is unknown to the prosthetic device (naive controller). By adopting a decoding strategy that identifies and focuses on units whose firing rate properties are best suited for control, we show that naive subjects mutually adapt to learn control of a neural prosthetic system. Six untrained Long-Evans rats, implanted with silicon micro-electrodes in the motor cortex, learned cortical control of an auditory device without prior motor characterization of the recorded neural ensemble. Single- and multi-unit activities were decoded using a Kalman filter to represent an audio "cursor" (90 ms tone pips ranging from 250 Hz to 16 kHz) which subjects controlled to match a given target frequency. After each trial, a novel adaptive algorithm trained the decoding filter based on correlations of the firing patterns with expected cursor movement. Each behavioral session consisted of 100 trials and began with randomized decoding weights. Within 7 +/- 1.4 (mean +/- SD) sessions, all subjects were able to significantly score above chance (P < 0.05, randomization method) in a fixed target paradigm. Training lasted 24 sessions in which both the behavioral performance and signal to noise ratio of the peri-event histograms increased significantly (P < 0.01, ANOVA). Two rats continued training on a more complex task using a bilateral, two-target control paradigm. Both subjects were able to significantly discriminate the target tones (P < 0.05, Z-test), while one subject demonstrated control above chance (P < 0.05, Z-test) after 12 sessions and continued improvement with many sessions achieving over 90% correct targets. Dynamic analysis of

  7. Pulvinar regulates information transmission between cortical areas based on attention demands#+

    PubMed Central

    Saalmann, Yuri B.; Pinsk, Mark A.; Wang, Liang; Li, Xin; Kastner, Sabine

    2013-01-01

    Selective attention mechanisms route behaviorally relevant information through large-scale cortical networks. While evidence suggests that populations of cortical neurons synchronize their activity to preferentially transmit information about attentional priorities, it is unclear how cortical synchrony across a network is accomplished. Based on its anatomical connectivity with the cortex, we hypothesized that the pulvinar, a thalamic nucleus, regulates cortical synchrony. We mapped pulvino-cortical networks within the visual system using diffusion tensor imaging and simultaneously recorded spikes and field potentials from these interconnected network sites in monkeys performing a visuo-spatial attention task. The pulvinar synchronized activity between interconnected cortical areas according to attentional allocation, suggesting not only a critical role for the thalamus in attentional selection, but more generally in regulating information transmission across visual cortex. PMID:22879517

  8. The pulvinar regulates information transmission between cortical areas based on attention demands.

    PubMed

    Saalmann, Yuri B; Pinsk, Mark A; Wang, Liang; Li, Xin; Kastner, Sabine

    2012-08-10

    Selective attention mechanisms route behaviorally relevant information through large-scale cortical networks. Although evidence suggests that populations of cortical neurons synchronize their activity to preferentially transmit information about attentional priorities, it is unclear how cortical synchrony across a network is accomplished. Based on its anatomical connectivity with the cortex, we hypothesized that the pulvinar, a thalamic nucleus, regulates cortical synchrony. We mapped pulvino-cortical networks within the visual system, using diffusion tensor imaging, and simultaneously recorded spikes and field potentials from these interconnected network sites in monkeys performing a visuospatial attention task. The pulvinar synchronized activity between interconnected cortical areas according to attentional allocation, suggesting a critical role for the thalamus not only in attentional selection but more generally in regulating information transmission across the visual cortex.

  9. A circuit for motor cortical modulation of auditory cortical activity.

    PubMed

    Nelson, Anders; Schneider, David M; Takatoh, Jun; Sakurai, Katsuyasu; Wang, Fan; Mooney, Richard

    2013-09-04

    Normal hearing depends on the ability to distinguish self-generated sounds from other sounds, and this ability is thought to involve neural circuits that convey copies of motor command signals to various levels of the auditory system. Although such interactions at the cortical level are believed to facilitate auditory comprehension during movements and drive auditory hallucinations in pathological states, the synaptic organization and function of circuitry linking the motor and auditory cortices remain unclear. Here we describe experiments in the mouse that characterize circuitry well suited to transmit motor-related signals to the auditory cortex. Using retrograde viral tracing, we established that neurons in superficial and deep layers of the medial agranular motor cortex (M2) project directly to the auditory cortex and that the axons of some of these deep-layer cells also target brainstem motor regions. Using in vitro whole-cell physiology, optogenetics, and pharmacology, we determined that M2 axons make excitatory synapses in the auditory cortex but exert a primarily suppressive effect on auditory cortical neuron activity mediated in part by feedforward inhibition involving parvalbumin-positive interneurons. Using in vivo intracellular physiology, optogenetics, and sound playback, we also found that directly activating M2 axon terminals in the auditory cortex suppresses spontaneous and stimulus-evoked synaptic activity in auditory cortical neurons and that this effect depends on the relative timing of motor cortical activity and auditory stimulation. These experiments delineate the structural and functional properties of a corticocortical circuit that could enable movement-related suppression of auditory cortical activity.

  10. A Circuit for Motor Cortical Modulation of Auditory Cortical Activity

    PubMed Central

    Nelson, Anders; Schneider, David M.; Takatoh, Jun; Sakurai, Katsuyasu; Wang, Fan

    2013-01-01

    Normal hearing depends on the ability to distinguish self-generated sounds from other sounds, and this ability is thought to involve neural circuits that convey copies of motor command signals to various levels of the auditory system. Although such interactions at the cortical level are believed to facilitate auditory comprehension during movements and drive auditory hallucinations in pathological states, the synaptic organization and function of circuitry linking the motor and auditory cortices remain unclear. Here we describe experiments in the mouse that characterize circuitry well suited to transmit motor-related signals to the auditory cortex. Using retrograde viral tracing, we established that neurons in superficial and deep layers of the medial agranular motor cortex (M2) project directly to the auditory cortex and that the axons of some of these deep-layer cells also target brainstem motor regions. Using in vitro whole-cell physiology, optogenetics, and pharmacology, we determined that M2 axons make excitatory synapses in the auditory cortex but exert a primarily suppressive effect on auditory cortical neuron activity mediated in part by feedforward inhibition involving parvalbumin-positive interneurons. Using in vivo intracellular physiology, optogenetics, and sound playback, we also found that directly activating M2 axon terminals in the auditory cortex suppresses spontaneous and stimulus-evoked synaptic activity in auditory cortical neurons and that this effect depends on the relative timing of motor cortical activity and auditory stimulation. These experiments delineate the structural and functional properties of a corticocortical circuit that could enable movement-related suppression of auditory cortical activity. PMID:24005287

  11. Components of vestibular cortical function.

    PubMed

    Klingner, Carsten M; Volk, Gerd F; Flatz, Claudia; Brodoehl, Stefan; Dieterich, Marianne; Witte, Otto W; Guntinas-Lichius, Orlando

    2013-01-01

    It is known that the functional response (e.g., nystagmus) to caloric vestibular stimulation is delayed and prolonged compared with the stimulus-response timing of other sensory systems. Imaging studies have used different models to predict cortical responses and to determine the areas of the brain that are involved. These studies have revealed a widespread network of vestibular brain regions. However, there is some disagreement regarding the brain areas involved, which may partly be caused by differences in the models used. This disagreement indicates the possible existence of multiple cortical components with different temporal characteristics that underlie cortical vestibular processing. However, data-driven methods have yet to be used to analyze the underlying hemodynamic components during and after vestibular stimulation. We performed functional magnetic resonance imaging (fMRI) on 12 healthy subjects during caloric stimulation and analyzed these data using a model-free analysis method (ICA). We found seven independent stimulus-induced components that outline a robust pattern of cortical activation and deactivation. These independent components demonstrated significant differences in their time courses. No single-modeled response function was able to cover the entire range of these independent components. The response functions determined in the present study should improve model-based studies investigating vestibular cortical processing.

  12. Cortical transients preceding voluntary movement.

    PubMed

    Hartwell, J W

    2009-12-01

    The process of initiating a voluntary muscular movement evidently involves a focusing of diffuse brain activity onto a highly specific location in the primary motor cortex. Even the very simple stereotypic movements used to study the 'contingent negative variation' and the 'readiness potential' begin with EEG indicative of widely distributed brain activity. In natural settings the involvement of diffuse cortical networks is undoubtedly even more important. Eventually, however, activity must coalesce onto specific neurons for the intended movement to ensue. Here we examine that focusing process from a mathematical point of view. Using a digital simulation, we solve the global equations for cortical dynamics and model the flow from diffuse onset to localized spike. From this perspective the interplay between global and local effects is seen as a necessary consequence of a basic cortical architecture which supports wave propagation. Watching the process evolve over time allows us to estimate some characteristic amplitudes and delays.

  13. Cortical myoclonus in Huntington's disease.

    PubMed

    Thompson, P D; Bhatia, K P; Brown, P; Davis, M B; Pires, M; Quinn, N P; Luthert, P; Honovar, M; O'Brien, M D; Marsden, C D

    1994-11-01

    We describe three patients with Huntington's disease, from two families, in whom myoclonus was the predominant clinical feature. The diagnosis was confirmed at autopsy in two cases and by DNA analysis in all three. These patients all presented before the age of 30 years and were the offspring of affected fathers. Neurophysiological studies documented generalised and multifocal action myoclonus of cortical origin that was strikingly stimulus sensitive, without enlargement of the cortical somatosensory evoked potential. The myoclonus improved with piracetam therapy in one patient and a combination of sodium valproate and clonazepam in the other two. Cortical reflex myoclonus is a rare but disabling component of the complex movement disorder of Huntington's disease, which may lead to substantial diagnostic difficulties.

  14. Cortical cartography reveals political and physical maps.

    PubMed

    Loring, David W; Gaillard, William Davis; Bookheimer, Susan Y; Meador, Kimford J; Ojemann, Jeffrey G

    2014-05-01

    Advances in functional imaging have provided noninvasive techniques to probe brain organization of multiple constructs including language and memory. Because of high overall rates of agreements with older techniques, including Wada testing and cortical stimulation mapping (CSM), some have proposed that those approaches should be largely abandoned because of their invasiveness, and replaced with noninvasive functional imaging methods. High overall agreement, however, is based largely on concordant language lateralization in series dominated by cases of typical cerebral dominance. Advocating a universal switch from Wada testing and cortical stimulation mapping to functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG) ignores the differences in specific expertise across epilepsy centers, many of which often have greater skill with one approach rather than the other, and that Wada, CSM, fMRI, and MEG protocols vary across institutions resulting in different outcomes and reliability. Specific patient characteristics also affect whether Wada or CSM might influence surgical management, making it difficult to accept broad recommendations against currently useful clinical tools. Although the development of noninvasive techniques has diminished the frequency of more invasive approaches, advocating their use to replace Wada testing and CSM across all epilepsy surgery programs without consideration of the different skills, protocols, and expertise at any given center site is ill-advised. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  15. Massive cortical reorganization in sighted Braille readers

    PubMed Central

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-01-01

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills. DOI: http://dx.doi.org/10.7554/eLife.10762.001 PMID:26976813

  16. Inferring Cortical Variability from Local Field Potentials

    PubMed Central

    Cui, Yuwei; Liu, Liu D.; McFarland, James M.; Pack, Christopher C.

    2016-01-01

    The responses of sensory neurons can be quite different to repeated presentations of the same stimulus. Here, we demonstrate a direct link between the trial-to-trial variability of cortical neuron responses and network activity that is reflected in local field potentials (LFPs). Spikes and LFPs were recorded with a multielectrode array from the middle temporal (MT) area of the visual cortex of macaques during the presentation of continuous optic flow stimuli. A maximum likelihood-based modeling framework was used to predict single-neuron spiking responses using the stimulus, the LFPs, and the activity of other recorded neurons. MT neuron responses were strongly linked to gamma oscillations (maximum at 40 Hz) as well as to lower-frequency delta oscillations (1–4 Hz), with consistent phase preferences across neurons. The predicted modulation associated with the LFP was largely complementary to that driven by visual stimulation, as well as the activity of other neurons, and accounted for nearly half of the trial-to-trial variability in the spiking responses. Moreover, the LFP model predictions accurately captured the temporal structure of noise correlations between pairs of simultaneously recorded neurons, and explained the variation in correlation magnitudes observed across the population. These results therefore identify signatures of network activity related to the variability of cortical neuron responses, and suggest their central role in sensory cortical function. SIGNIFICANCE STATEMENT The function of sensory neurons is nearly always cast in terms of representing sensory stimuli. However, recordings from visual cortex in awake animals show that a large fraction of neural activity is not predictable from the stimulus. We show that this variability is predictable given the simultaneously recorded measures of network activity, local field potentials. A model that combines elements of these signals with the stimulus processing of the neuron can predict neural

  17. Inferring Cortical Variability from Local Field Potentials.

    PubMed

    Cui, Yuwei; Liu, Liu D; McFarland, James M; Pack, Christopher C; Butts, Daniel A

    2016-04-06

    The responses of sensory neurons can be quite different to repeated presentations of the same stimulus. Here, we demonstrate a direct link between the trial-to-trial variability of cortical neuron responses and network activity that is reflected in local field potentials (LFPs). Spikes and LFPs were recorded with a multielectrode array from the middle temporal (MT) area of the visual cortex of macaques during the presentation of continuous optic flow stimuli. A maximum likelihood-based modeling framework was used to predict single-neuron spiking responses using the stimulus, the LFPs, and the activity of other recorded neurons. MT neuron responses were strongly linked to gamma oscillations (maximum at 40 Hz) as well as to lower-frequency delta oscillations (1-4 Hz), with consistent phase preferences across neurons. The predicted modulation associated with the LFP was largely complementary to that driven by visual stimulation, as well as the activity of other neurons, and accounted for nearly half of the trial-to-trial variability in the spiking responses. Moreover, the LFP model predictions accurately captured the temporal structure of noise correlations between pairs of simultaneously recorded neurons, and explained the variation in correlation magnitudes observed across the population. These results therefore identify signatures of network activity related to the variability of cortical neuron responses, and suggest their central role in sensory cortical function. The function of sensory neurons is nearly always cast in terms of representing sensory stimuli. However, recordings from visual cortex in awake animals show that a large fraction of neural activity is not predictable from the stimulus. We show that this variability is predictable given the simultaneously recorded measures of network activity, local field potentials. A model that combines elements of these signals with the stimulus processing of the neuron can predict neural responses dramatically better

  18. Abnormalities of cortical structures in adolescent-onset conduct disorder.

    PubMed

    Jiang, Y; Guo, X; Zhang, J; Gao, J; Wang, X; Situ, W; Yi, J; Zhang, X; Zhu, X; Yao, S; Huang, B

    2015-12-01

    Converging evidence has revealed both functional and structural abnormalities in adolescents with early-onset conduct disorder (EO-CD). The neurological abnormalities underlying EO-CD may be different from that of adolescent-onset conduct disorder (AO-CD) patients. However, the cortical structure in AO-CD patients remains largely unknown. The aim of the present study was to investigate the cortical alterations in AO-CD patients. We investigated T1-weighted brain images from AO-CD patients and age-, gender- and intelligence quotient-matched controls. Cortical structures including thickness, folding and surface area were measured using the surface-based morphometric method. Furthermore, we assessed impulsivity and antisocial symptoms using the Barratt Impulsiveness Scale (BIS) and the Antisocial Process Screening Device (APSD). Compared with the controls, we found significant cortical thinning in the paralimbic system in AO-CD patients. For the first time, we observed cortical thinning in the precuneus/posterior cingulate cortex (PCC) in AO-CD patients which has not been reported in EO-CD patients. Prominent folding abnormalities were found in the paralimbic structures and frontal cortex while diminished surface areas were shown in the precentral and inferior temporal cortex. Furthermore, cortical thickness of the paralimbic structures was found to be negatively correlated with impulsivity and antisocial behaviors measured by the BIS and APSD, respectively. The present study indicates that AO-CD is characterized by cortical structural abnormalities in the paralimbic system, and, in particular, we highlight the potential role of deficient structures including the precuneus and PCC in the etiology of AO-CD.

  19. Reorganization of human cortical maps caused by inherited photoreceptor abnormalities.

    PubMed

    Baseler, Heidi A; Brewer, Alyssa A; Sharpe, Lindsay T; Morland, Antony B; Jägle, Herbert; Wandell, Brian A

    2002-04-01

    We describe a compelling demonstration of large-scale developmental reorganization in the human visual pathways. The developmental reorganization was observed in rod monochromats, a rare group of congenitally colorblind individuals who virtually lack cone photoreceptor function. Normal controls had a cortical region, spanning several square centimeters, that responded to signals initiated in the all-cone foveola but was inactive under rod viewing conditions; in rod monochromats this cortical region responded powerfully to rod-initiated signals. The measurements trace a causal pathway that begins with a genetic anomaly that directly influences sensory cells and ultimately results in a substantial central reorganization.

  20. Illusory movements prevent cortical disruption caused by immobilization.

    PubMed

    Roll, R; Kavounoudias, A; Albert, F; Legré, R; Gay, A; Fabre, B; Roll, J P

    2012-08-01

    Enforced limb disuse strongly disrupts the cortical networks that are involved in sensorimotor activities. This disruption causes a cortical reorganization that may be functionally maladaptive. In this study, we used functional magnetic resonance imaging (fMRI) to investigate whether it is possible to prevent this reorganization by compensating for the lack of actual kinesthetic perception with illusory movements induced by "neuromimetic" proprio-tactile feedback that is artificially delivered during immobilization. Sixteen healthy volunteers were equipped for five days with full-hand ortheses that prevented them from performing finger and hand movements but allowed for kinesthetic and tactile sensations. Eight participants received a twice-daily proprio-tactile treatment consisting of the perception of kinesthetic sensations resembling those felt during actual movements generated by miniature vibrators set in the ortheses at the finger and wrist levels. Eight untreated participants received no stimulation. The effects of hand immobilization and treatment were assessed by fMRI during a calibrated voluntary hand movement task and hand tactile stimulation before cast placement and immediately after cast removal. We found that the sensorimotor network was preserved in subjects who underwent this treatment during hand immobilization, while the sensorimotor network of untreated subjects was significantly altered. These findings suggest that sensory feedback and associated movement perception may counteract disuse-induced cortical plastic changes through recruitment of a large part of the cortical network used for actual performed movement. The possibility of guiding cortical plasticity with proprioceptive augmented feedback is potentially relevant for rehabilitation efforts.

  1. Phase II Radiation Therapy Oncology Group trial of conventional radiation therapy followed by treatment with recombinant interferon-{beta} for supratentorial glioblastoma: Results of RTOG 9710

    SciTech Connect

    Colman, Howard . E-mail: hcolman@mdanderson.org; Berkey, Brian A.; Maor, Moshe H.; Groves, Morris D.; Schultz, Christopher J.; Vermeulen, Sandra; Mehta, Minesh P.; Yung, W.K. Alfred

    2006-11-01

    Purpose: The aim of this study was to determine whether recombinant human interferon {beta}-1a (rhIFN-{beta}), when given after radiation therapy, improves survival in glioblastoma. Methods and Materials: After surgery, 109 patients with newly diagnosed supratentorial glioblastoma were enrolled and treated with radiation therapy (60 Gy). A total of 55 patients remained stable after radiation and were treated with rhIFN-{beta} (6 MU/day i.m., 3 times/week). Outcomes were compared with Radiation Therapy Oncology Group glioma historical database. Results: RhIFN-{beta} was well tolerated, with 1 Grade 4 toxicity and 8 other patients experiencing Grade 3 toxicity. Median survival time (MST) of the 55 rhIFN-{beta}-treated patients was 13.4 months. MST for the 34 rhIFN-{beta}-treated in RPA Classes III and IV was 16.9 vs. 12.4 months for historical controls (hazard ratio [HR] = 1.27, 95% confidence interval [CI] = 0.89-1.81). There was also a trend toward improved survival across all RPA Classes comparing the 55 rhIFN-{beta} treated patients and 1,658 historical controls (HR = 1.24, 95% CI = 0.94-1.63). The high rate of early failures (54/109) after radiation and before initiation of rhIFN-{beta} was likely caused by stricter interpretation of early radiographic changes in the current study. Matched-pair and intent-to-treat analyses performed to try to address this bias showed no difference in survival between study patients and controls. Conclusion: RhIFN-{beta} given after conventional radiation therapy was well tolerated, with a trend toward survival benefit in patients who remained stable after radiation therapy. These data suggest that rhIFN-{beta} warrants further evaluation in additional studies, possibly in combination with current temozolomide-based regimens.

  2. Non-pineal supratentorial primitive neuro-ectodermal tumors (sPNET) in teenagers and young adults: Time to reconsider cisplatin based chemotherapy after cranio-spinal irradiation?

    PubMed

    Biswas, Swethajit; Burke, Amos; Cherian, Sheen; Williams, Denise; Nicholson, James; Horan, Gail; Jefferies, Sarah; Williams, Michael; Earl, Helena M; Burnet, Neil G; Hatcher, Helen

    2009-07-01

    Supratentorial PNET (sPNET) are rare CNS tumors of embryonal origin arising in children and adults. The treatment of sPNET for all age groups at our cancer center has been based on the management of medulloblastoma (MB), involving neurosurgical debulking followed by cranio-spinal irradiation (CSI) and systemic chemotherapy. Medical records were reviewed to gather demographic and clinical data about all embryonal CNS tumors in children and adults from 2001 to 2007. Tumor pathology, clinical management and survival data were also assessed, particularly as regards those patients who received the Packer chemotherapy regimen for either sPNET or MB. Eleven patients (five children and six adults) were identified with non-pineal sPNET, three children with pineal sPNET, and 19 patients (18 children and 1 adult) with MB. There was no difference in overall survival (OS) rates between pediatric and adult sPNET. When all sPNET were compared to all MB, 5-year OS was 14% versus 73%, respectively, but was only 9% for non-pineal sPNET. When only considering those patients treated with the Packer chemotherapy regimen, the 5-year OS was 12% for sPNET versus 79% for MB. This retrospective study demonstrates that non-pineal sPNET are clinically distinct from MB and are resistant to the Packer chemotherapy regimen. We suggest that it is time to reconsider the use of this regimen in teenage and young adult non-pineal sPNET and to investigate the utility of alternative approaches. (c) 2009 Wiley-Liss, Inc.

  3. Randomized trial of radiation therapy plus procarbazine, lomustine, and vincristine chemotherapy for supratentorial adult low-grade glioma: initial results of RTOG 9802.

    PubMed

    Shaw, Edward G; Wang, Meihua; Coons, Stephen W; Brachman, David G; Buckner, Jan C; Stelzer, Keith J; Barger, Geoffrey R; Brown, Paul D; Gilbert, Mark R; Mehta, Minesh P

    2012-09-01

    A prior Radiation Therapy Oncology Group (RTOG) clinical trial in anaplastic oligodendroglioma suggested a progression-free survival benefit for procarbazine, lomustine, and vincristine (PCV) chemotherapy in addition to radiation therapy (RT), as have smaller trials in low-grade glioma (LGG). Eligibility criteria included supratentorial WHO grade 2 LGG, age 18 to 39 years with subtotal resection/biopsy, or age ≥ 40 years with any extent resection. Patients were randomly assigned to RT alone or RT followed by six cycles of PCV. Survival was compared by using the modified Wilcoxon and log-rank tests. In all, 251 patients were accrued from 1998 to 2002. Median overall survival (OS) time and 5-year OS rates for RT versus RT + PCV were 7.5 years versus not reached and 63% versus 72%, respectively (hazard ratio [HR]; 0.72; 95% CI, 0.47 to 1.10; P = .33; log-rank P = .13). Median progression-free survival (PFS) time and 5-year PFS rates for RT versus RT + PCV were 4.4 years versus not reached and 46% versus 63%, respectively (HR, 0.6; 95% CI, 0.41 to 0.86; P = .06; log-rank P = .005). OS and PFS were similar for all patients between years 0 and 2. After 2 years, OS and PFS curves separated significantly, favoring RT + PCV. For 2-year survivors (n = 211), the probability of OS for an additional 5 years was 74% with RT + PCV versus 59% with RT alone (HR, 0.52; 95% CI, 0.30 to 0.90; log-rank P = .02). PFS but not OS was improved for adult patients with LGG receiving RT + PCV versus RT alone. On post hoc analysis, for 2-year survivors, the addition of PCV to RT conferred a survival advantage, suggesting a delayed benefit for chemotherapy.

  4. Randomized Trial of Radiation Therapy Plus Procarbazine, Lomustine, and Vincristine Chemotherapy for Supratentorial Adult Low-Grade Glioma: Initial Results of RTOG 9802

    PubMed Central

    Shaw, Edward G.; Wang, Meihua; Coons, Stephen W.; Brachman, David G.; Buckner, Jan C.; Stelzer, Keith J.; Barger, Geoffrey R.; Brown, Paul D.; Gilbert, Mark R.; Mehta, Minesh P.

    2012-01-01

    Purpose A prior Radiation Therapy Oncology Group (RTOG) clinical trial in anaplastic oligodendroglioma suggested a progression-free survival benefit for procarbazine, lomustine, and vincristine (PCV) chemotherapy in addition to radiation therapy (RT), as have smaller trials in low-grade glioma (LGG). Patients and Methods Eligibility criteria included supratentorial WHO grade 2 LGG, age 18 to 39 years with subtotal resection/biopsy, or age ≥ 40 years with any extent resection. Patients were randomly assigned to RT alone or RT followed by six cycles of PCV. Survival was compared by using the modified Wilcoxon and log-rank tests. Results In all, 251 patients were accrued from 1998 to 2002. Median overall survival (OS) time and 5-year OS rates for RT versus RT + PCV were 7.5 years versus not reached and 63% versus 72%, respectively (hazard ratio [HR]; 0.72; 95% CI, 0.47 to 1.10; P = .33; log-rank P = .13). Median progression-free survival (PFS) time and 5-year PFS rates for RT versus RT + PCV were 4.4 years versus not reached and 46% versus 63%, respectively (HR, 0.6; 95% CI, 0.41 to 0.86; P = .06; log-rank P = .005). OS and PFS were similar for all patients between years 0 and 2. After 2 years, OS and PFS curves separated significantly, favoring RT + PCV. For 2-year survivors (n = 211), the probability of OS for an additional 5 years was 74% with RT + PCV versus 59% with RT alone (HR, 0.52; 95% CI, 0.30 to 0.90; log-rank P = .02). Conclusion PFS but not OS was improved for adult patients with LGG receiving RT + PCV versus RT alone. On post hoc analysis, for 2-year survivors, the addition of PCV to RT conferred a survival advantage, suggesting a delayed benefit for chemotherapy. PMID:22851558

  5. Functional imaging of cortical feedback projections to the olfactory bulb

    PubMed Central

    Rothermel, Markus; Wachowiak, Matt

    2014-01-01

    Processing of sensory information is substantially shaped by centrifugal, or feedback, projections from higher cortical areas, yet the functional properties of these projections are poorly characterized. Here, we used genetically-encoded calcium sensors (GCaMPs) to functionally image activation of centrifugal projections targeting the olfactory bulb (OB). The OB receives massive centrifugal input from cortical areas but there has been as yet no characterization of their activity in vivo. We focused on projections to the OB from the anterior olfactory nucleus (AON), a major source of cortical feedback to the OB. We expressed GCaMP selectively in AON projection neurons using a mouse line expressing Cre recombinase (Cre) in these neurons and Cre-dependent viral vectors injected into AON, allowing us to image GCaMP fluorescence signals from their axon terminals in the OB. Electrical stimulation of AON evoked large fluorescence signals that could be imaged from the dorsal OB surface in vivo. Surprisingly, odorants also evoked large signals that were transient and coupled to odorant inhalation both in the anesthetized and awake mouse, suggesting that feedback from AON to the OB is rapid and robust across different brain states. The strength of AON feedback signals increased during wakefulness, suggesting a state-dependent modulation of cortical feedback to the OB. Two-photon GCaMP imaging revealed that different odorants activated different subsets of centrifugal AON axons and could elicit both excitation and suppression in different axons, indicating a surprising richness in the representation of odor information by cortical feedback to the OB. Finally, we found that activating neuromodulatory centers such as basal forebrain drove AON inputs to the OB independent of odorant stimulation. Our results point to the AON as a multifunctional cortical area that provides ongoing feedback to the OB and also serves as a descending relay for other neuromodulatory systems. PMID

  6. Comparative aspects of cortical neurogenesis in vertebrates.

    PubMed

    Cheung, Amanda F P; Pollen, Alexander A; Tavare, Aniket; DeProto, Jamin; Molnár, Zoltán

    2007-08-01

    cortical column appears to be largely constant; nevertheless, there are considerable differences between the germinal zones in mammalian species. It is yet to be determined whether these elaborations of the subventricular zone may have contributed to cell diversity, tangential expansion or gyrus formation of the neocortex and whether it might have been the major driving force behind the evolution of the six-layered neocortex in mammals.

  7. Motor cortical thresholds and cortical silent periods in epilepsy.

    PubMed

    Tataroglu, Cengiz; Ozkiziltan, Safa; Baklan, Baris

    2004-10-01

    We studied motor cortical thresholds (TIs) and cortical silent periods (SPs) evoked by transcranial magnetic stimulation (TMS) in 110 epileptic patients. Sixty-two had primary generalised, 48 had partial type seizures. Fifteen out 110 patients were analysed both before and after anticonvulsant medication. Our aims were to evaluate the TI levels and the duration of SPs in patients with epilepsy and to determine the reliability of TMS in patients with epilepsy. There was no negative effect of TMS on the clinical status and EEG findings in patients with epilepsy. TIs obtained from patients with partial epilepsy were higher than those obtained from both controls and primary epileptics. The duration of SP in patients with primary epileptics was more prolonged than those obtained from controls. There was no correlation between EEG lateralisation and both SP duration and TI values. In de novo patient group, SP duration was significantly prolonged after anticonvulsant medication. We concluded that TMS is a reliable electrophysiological investigation in patients with epilepsy. The analysis of SP duration may be an appropriate investigation in monitoring the effect of anticonvulsant medication on the cortical inhibitory activity.

  8. Laminar cortical necrosis in mitochondrial disorders.

    PubMed

    Finsterer, Josef

    2009-10-01

    Laminar cortical necrosis, defined as focal or diffuse necrosis of one or more cortical lamina, represents an increasingly recognized neuropathological endpoint of vascular, endocrine, immunologic, metabolic, or toxic conditions, of which mitochondrial disorders (MIDs) are the third most frequent after cerebral ischemia and hypoxia. To investigate the prevalence of laminar cortical necrosis in MIDs, types of MIDs associated with laminar cortical necrosis, and the morphological characteristics on imaging and autopsy. Medline literature review for the terms "laminar cortical necrosis", "cortical signal change", "mitochondrial" and all acronyms of syndromatic MIDs. Among 139 hits for "laminar cortical necrosis", 10 articles fulfilled the inclusion criteria (7%). Among the ten hits five were case series and the other five single case reports. The syndromic MID most frequently associated with laminar cortical necrosis is the MELAS syndrome, but was also described in a single patient each with Leigh syndrome, mitochondrial depletion syndrome, and mitochondrial spinocerebellar ataxia. The morphological and pathohistological features of laminar cortical necrosis in MIDs were not at variance from those in non-mitochondrial disorders. In MIDs laminar cortical necrosis represents the histopathological and imaging endpoint of a stroke-like lesion. Though laminar cortical necrosis may have a wide pathophysiological background the histological and imaging characteristics do not vary between the different underlying conditions.

  9. Dynamic reconfiguration of cortical functional connectivity across brain states.

    PubMed

    Stitt, Iain; Hollensteiner, Karl J; Galindo-Leon, Edgar; Pieper, Florian; Fiedler, Eva; Stieglitz, Thomas; Engler, Gerhard; Nolte, Guido; Engel, Andreas K

    2017-08-18

    Throughout each day, the brain displays transient changes in state, as evidenced by shifts in behavior and vigilance. While the electrophysiological correlates of brain states have been studied for some time, it remains unclear how large-scale cortico-cortical functional connectivity systematically reconfigures across states. Here, we investigate state-dependent shifts in cortical functional connectivity by recording local field potentials (LFPs) during spontaneous behavioral transitions in the ferret using chronically implanted micro-electrocorticographic (µECoG) arrays positioned over occipital, parietal, and temporal cortical regions. To objectively classify brain state, we describe a data-driven approach that projects time-varying LFP spectral properties into brain state space. Distinct brain states displayed markedly different patterns of cross-frequency phase-amplitude coupling and inter-electrode phase synchronization across several LFP frequency bands. The largest across-state differences in functional connectivity were observed between periods of presumed slow-wave and rapid-eye-movement-sleep/active-state, which were characterized by the contrasting phenomena of cortical network fragmentation and global synchronization, respectively. Collectively, our data provide strong evidence that large-scale functional interactions in the brain dynamically reconfigure across behavioral states.

  10. Spontaneous cortical activity is transiently poised close to criticality

    PubMed Central

    Monier, Cyril; Kumar, Arvind; Deco, Gustavo; Frégnac, Yves

    2017-01-01

    Brain activity displays a large repertoire of dynamics across the sleep-wake cycle and even during anesthesia. It was suggested that criticality could serve as a unifying principle underlying the diversity of dynamics. This view has been supported by the observation of spontaneous bursts of cortical activity with scale-invariant sizes and durations, known as neuronal avalanches, in recordings of mesoscopic cortical signals. However, the existence of neuronal avalanches in spiking activity has been equivocal with studies reporting both its presence and absence. Here, we show that signs of criticality in spiking activity can change between synchronized and desynchronized cortical states. We analyzed the spontaneous activity in the primary visual cortex of the anesthetized cat and the awake monkey, and found that neuronal avalanches and thermodynamic indicators of criticality strongly depend on collective synchrony among neurons, LFP fluctuations, and behavioral state. We found that synchronized states are associated to criticality, large dynamical repertoire and prolonged epochs of eye closure, while desynchronized states are associated to sub-criticality, reduced dynamical repertoire, and eyes open conditions. Our results show that criticality in cortical dynamics is not stationary, but fluctuates during anesthesia and between different vigilance states. PMID:28542191

  11. Nonlinear mechanisms of cortical oscillations.

    PubMed

    Kowalik, Z J

    2000-01-01

    Not only theoretical consideration but also analyses of MEG or EEG recordings prove the nonlinear character of cortical dynamics. For instance, an averaged local Lyapunov Exponents (ILE) have positive value that is characteristic for chaotic dynamics. Also a test for nonlinearity (or determinism)--so called surrogate data test distinguishes between original- and randomized-phase time-series proving that recorded signals are nonlinear. These facts are a very strong experimental evidence to support the hypothesis that brain oscillators are governed by the deterministic, nonlinear, low-dimensional dynamics. The experimental manifestations of nonlinear cortical oscillations in the healthy and pathologically altered human brain and their deterministic character seems to be an important step in the understanding brain dynamics in the language of nonlinear systems theory. Clinical application may use nonlinear measures (especially ILE, and PD2i) for classification of pathologies and rough localization of the functional disturbance in the brain.

  12. Imprinting and recalling cortical ensembles.

    PubMed

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S; Yuste, Rafael

    2016-08-12

    Neuronal ensembles are coactive groups of neurons that may represent building blocks of cortical circuits. These ensembles could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations from ensembles in the visual cortex of awake mice builds neuronal ensembles that recur spontaneously after being imprinted and do not disrupt preexisting ones. Moreover, imprinted ensembles can be recalled by single- cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. Copyright © 2016, American Association for the Advancement of Science.

  13. Extrathalamic Modulation of Cortical Function

    DTIC Science & Technology

    1990-07-27

    and c7rtico-cortical systems. For example, we have shown that primate LC-NA neurons are more acti during waking than sleep and exhibit bursts of...infusion needle. Infusion of the alpha-adrenergic agonist clonidine (CLON), in concentrations ranging from 5-20 uM (67-270pg/50 nl injection...ind hippocampal EEG (HEEG) typically exhibit activity similar to that of a lightly sleeping animal. However, periods of "waking" EEG are sometimes

  14. [Infantile cortical hyperostosis: Case report].

    PubMed

    Rodríguez, Mónica; Martínez, Luz Elena; Cortés, José; de Uña, Armando; Vega, Valentina; Acosta, Mario

    Infantile Cortical Hyperostosis, or Caffey-Silverman disease, is a rare condition characterised by generalised bone proliferation mediated by an acute inflammatory process. Diagnosis can be made through clinical evaluation and X-ray studies. The course is generally self-limiting and prognosis is excellent. To present the case of a 4-month child with clinical and radiological symptoms compatible with Infantile Cortical Hyperostosis. A 4-month old male who presented with crying and irritability associated with swelling of the face, arms and legs was admitted to the Emergency Room of National Institute of Pediatrics. Bilateral mandibular swelling extending to periauricular region was observed, with no signs of inflammation. X-ray studies showed a periosteal reaction in the jaw, left femur and tibia, and radius bilateral. Clinical observation combined with analgesics and antipyretics was the only medical intervention. Four to six months after discharge from hospital, the symptoms disappeared, confirming the good prognosis of this condition. Infantile cortical hyperostosis is a collagenopathy, which must be considered as a differential diagnosis in acute bone inflammatory processes, irritability and fever. It is important to understand and identify this disease and clinical-radiological correlation is remarkable. Copyright © 2016 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. [Parietal Cortices and Body Information].

    PubMed

    Naito, Eiichi; Amemiya, Kaoru; Morita, Tomoyo

    2016-11-01

    Proprioceptive signals originating from skeletal muscles and joints contribute to the formation of both the human body schema and the body image. In this chapter, we introduce various types of bodily illusions that are elicited by proprioceptive inputs, and we discuss distinct functions implemented by different parietal cortices. First, we illustrate the primary importance of the motor network in the processing of proprioceptive (kinesthetic) signals originating from muscle spindles. Next, we argue that the right inferior parietal cortex, in concert with the inferior frontal cortex (both regions connected by the inferior branch of the superior longitudinal fasciculus-SLF III), may be involved in the conscious experience of body image. Further, we hypothesize other functions of distinct parietal regions: the association between internal hand motor representation with external object representation in the left inferior parietal cortex, visuo-kinesthetic processing in the bilateral posterior parietal cortices, and the integration of somatic signals from different body parts in the higher-order somatosensory parietal cortices. Our results indicate that a distinct parietal region, in concert with its anatomically and functionally connected frontal regions, probably plays specialized roles in the processing of body-related information.

  16. Cortical Interneurons Require Jnk1 to Enter and Navigate the Developing Cerebral Cortex

    PubMed Central

    Myers, Abigail K.; Meechan, Daniel W.; Adney, Danielle R.

    2014-01-01

    Proper assembly of cortical circuitry relies on the correct migration of cortical interneurons from their place of birth in the ganglionic eminences to their place of terminal differentiation in the cerebral cortex. Although molecular mechanisms mediating cortical interneuron migration have been well studied, intracellular signals directing their migration are largely unknown. Here we illustrate a novel and essential role for c-Jun N-terminal kinase (JNK) signaling in guiding the pioneering population of cortical interneurons into the mouse cerebral cortex. Migrating cortical interneurons express Jnk proteins at the entrance to the cortical rudiment and have enriched expression of Jnk1 relative to noninterneuronal cortical cells. Pharmacological blockade of JNK signaling in ex vivo slice cultures resulted in dose-dependent and highly specific disruption of interneuron migration into the nascent cortex. Time-lapse imaging revealed that JNK-inhibited cortical interneurons advanced slowly and assumed aberrant migratory trajectories while traversing the cortical entry zone. In vivo analyses of JNK-deficient embryos supported our ex vivo pharmacological data. Deficits in interneuron migration were observed in Jnk1 but not Jnk2 single nulls, and those migratory deficits were further exacerbated when homozygous loss of Jnk1 was combined with heterozygous reduction of Jnk2. Finally, genetic ablation of Jnk1 and Jnk2 from cortical interneurons significantly perturbed migration in vivo, but not in vitro, suggesting JNK activity functions to direct their guidance rather than enhance their motility. These data suggest JNK signaling, predominantly mediated by interneuron expressed Jnk1, is required for guiding migration of cortical interneurons into and within the developing cerebral cortex. PMID:24899703

  17. Extraversion and cortical activation during memory performance.

    PubMed

    Fink, A; Grabner, R H; Neuper, C; Neubauer, A C

    2005-05-01

    In this study we analyzed the influence of the personality dimension extraversion-introversion (E) on the level and topographical distribution of cortical activation. In 62 participants (32 introverts and 30 extraverts), we measured the extent of Event-Related Desynchronization (ERD) in the EEG during performance of a short-term memory (i.e., temporary maintenance of information) and a more complex working memory task (i.e., temporary maintenance and active manipulation of information). The results indicate that during performance of both tasks, introverts display a larger amount of ERD than extraverted individuals. Moreover, the present E effects largely match previous studies as to the restriction of these effects to lower EEG frequency ranges (approx. 4-8 Hz). Topographical analyses show that the E effects are primarily present over (right-hemispheric) frontal and parietal regions of the cerebral cortex.

  18. Hippocampal-cortical interaction in decision making

    PubMed Central

    Yu, Jai Y.; Frank, Loren M.

    2014-01-01

    When making a decision it is often necessary to consider the available alternatives in order to choose the most appropriate option. This deliberative process, where the pros and cons of each option are considered, relies on memories of past actions and outcomes. The hippocampus and prefrontal cortex are required for memory encoding, memory retrieval and decision making, but it is unclear how these areas support deliberation. Here we examine the potential neural substrates of these processes in the rat. The rat is a powerful model to investigate the network mechanisms underlying deliberation in the mammalian brain given the anatomical and functional conservation of its hippocampus and prefrontal cortex to other mammalian systems. Importantly, it is amenable to large scale neural recording while performing laboratory tasks that exploit its natural decisionmaking behavior. Focusing on findings in the rat, we discuss how hippocampal-cortical interactions could provide a neural substrate for deliberative decision making. PMID:24530374

  19. Hippocampal-cortical interaction in decision making.

    PubMed

    Yu, Jai Y; Frank, Loren M

    2015-01-01

    When making a decision it is often necessary to consider the available alternatives in order to choose the most appropriate option. This deliberative process, where the pros and cons of each option are considered, relies on memories of past actions and outcomes. The hippocampus and prefrontal cortex are required for memory encoding, memory retrieval and decision making, but it is unclear how these areas support deliberation. Here we examine the potential neural substrates of these processes in the rat. The rat is a powerful model to investigate the network mechanisms underlying deliberation in the mammalian brain given the anatomical and functional conservation of its hippocampus and prefrontal cortex to other mammalian systems. Importantly, it is amenable to large scale neural recording while performing laboratory tasks that exploit its natural decision-making behavior. Focusing on findings in the rat, we discuss how hippocampal-cortical interactions could provide a neural substrate for deliberative decision making.

  20. Geometric and functional organization of cortical circuits.

    PubMed

    Shepherd, Gordon M G; Stepanyants, Armen; Bureau, Ingrid; Chklovskii, Dmitri; Svoboda, Karel

    2005-06-01

    Can neuronal morphology predict functional synaptic circuits? In the rat barrel cortex, 'barrels' and 'septa' delineate an orderly matrix of cortical columns. Using quantitative laser scanning photostimulation we measured the strength of excitatory projections from layer 4 (L4) and L5A to L2/3 pyramidal cells in barrel- and septum-related columns. From morphological reconstructions of excitatory neurons we computed the geometric circuit predicted by axodendritic overlap. Within most individual projections, functional inputs were predicted by geometry and a single scale factor, the synaptic strength per potential synapse. This factor, however, varied between projections and, in one case, even within a projection, up to 20-fold. Relationships between geometric overlap and synaptic strength thus depend on the laminar and columnar locations of both the pre- and postsynaptic neurons, even for neurons of the same type. A large plasticity potential appears to be incorporated into these circuits, allowing for functional 'tuning' with fixed axonal and dendritic arbor geometry.

  1. Interhemispheric Connectivity Characterizes Cortical Reorganization in Motor-Related Networks After Cerebellar Lesions.

    PubMed

    De Vico Fallani, Fabrizio; Clausi, Silvia; Leggio, Maria; Chavez, Mario; Valencia, Miguel; Maglione, Anton Giulio; Babiloni, Fabio; Cincotti, Febo; Mattia, Donatella; Molinari, Marco

    2017-04-01

    Although cerebellar-cortical interactions have been studied extensively in animal models and humans using modern neuroimaging techniques, the effects of cerebellar stroke and focal lesions on cerebral cortical processing remain unknown. In the present study, we analyzed the large-scale functional connectivity at the cortical level by combining high-density electroencephalography (EEG) and source imaging techniques to evaluate and quantify the compensatory reorganization of brain networks after cerebellar damage. The experimental protocol comprised a repetitive finger extension task by 10 patients with unilateral focal cerebellar lesions and 10 matched healthy controls. A graph theoretical approach was used to investigate the functional reorganization of cortical networks. Our patients, compared with controls, exhibited significant differences at global and local topological level of their brain networks. An abnormal rise in small-world network efficiency was observed in the gamma band (30-40 Hz) during execution of the task, paralleled by increased long-range connectivity between cortical hemispheres. Our findings show that a pervasive reorganization of the brain network is associated with cerebellar focal damage and support the idea that the cerebellum boosts or refines cortical functions. Clinically, these results suggest that cortical changes after cerebellar damage are achieved through an increase in the interactions between remote cortical areas and that rehabilitation should aim to reshape functional activation patterns. Future studies should determine whether these hypotheses are limited to motor tasks or if they also apply to cerebro-cerebellar dysfunction in general.

  2. Growth and Age-Related Abnormalities in Cortical Structure and Fracture Risk

    PubMed Central

    2015-01-01

    Vertebral fractures and trabecular bone loss have dominated thinking and research into the pathogenesis and the structural basis of bone fragility during the last 70 years. However, 80% of all fractures are non-vertebral and occur at regions assembled using large amounts of cortical bone; only 20% of fractures are vertebral. Moreover, ~80% of the skeleton is cortical and ~70% of all bone loss is cortical even though trabecular bone is lost more rapidly than cortical bone. Bone is lost because remodelling becomes unbalanced after midlife. Most cortical bone loss occurs by intracortical, not endocortical remodelling. Each remodelling event removes more bone than deposited enlarging existing canals which eventually coalesce eroding and thinning the cortex from 'within.' Thus, there is a need to study the decay of cortical as well as trabecular bone, and to develop drugs that restore the strength of both types of bone. It is now possible to accurately quantify cortical porosity and trabecular decay in vivo. The challenges still to be met are to determine whether measurement of porosity identifies persons at risk for fracture, whether this approach is compliments information obtained using bone densitometry, and whether changes in cortical porosity and other microstructural traits have the sensitivity to serve as surrogates of treatment success or failure. PMID:26394727

  3. Phase 1/2 Trials of Temozolomide, Motexafin Gadolinium, and 60-Gy Fractionated Radiation for Newly Diagnosed Supratentorial Glioblastoma Multiforme: Final Results of RTOG 0513

    SciTech Connect

    Brachman, David G.; Pugh, Stephanie L.; Ashby, Lynn S.; Thomas, Theresa A.; Dunbar, Erin M.; Narayan, Samir; Robins, H. Ian; Bovi, Joseph A.; Rockhill, Jason K.; Won, Minhee; Curran, Walter P.

    2015-04-01

    Purpose: The purpose of phase 1 was to determine the maximum tolerated dose (MTD) of motexafin gadolinium (MGd) given concurrently with temozolomide (TMZ) and radiation therapy (RT) in patients with newly diagnosed supratentorial glioblastoma multiforme (GBM). Phase 2 determined whether this combination improved overall survival (OS) and progression-free survival (PFS) in GBM recursive partitioning analysis class III to V patients compared to therapies for recently published historical controls. Methods and Materials: Dose escalation in phase 1 progressed through 3 cohorts until 2 of 6 patients experienced dose-limiting toxicity or a dose of 5 mg/kg was reached. Once MTD was established, a 1-sided 1-sample log-rank test at significance level of .1 had 85% power to detect a median survival difference (13.69 vs 18.48 months) with 60 deaths over a 12-month accrual period and an additional 18 months of follow-up. OS and PFS were estimated using the Kaplan-Meier method. Results: In phase 1, 24 patients were enrolled. The MTD established was 5 mg/kg, given intravenously 5 days a week for the first 10 RT fractions, then 3 times a week for the duration of RT. The 7 patients enrolled in the third dose level and the 94 enrolled in phase 2 received this dose. Of these 101 patients, 87 were eligible and evaluable. Median survival time was 15.6 months (95% confidence interval [CI]: 12.9-17.6 months), not significantly different from that of the historical control (P=.36). Median PFS was 7.6 months (95% CI: 5.7-9.6 months). One patient (1%) experienced a grade 5 adverse event possibly related to therapy during the concurrent phase, and none experience toxicity during adjuvant TMZ therapy. Conclusions: Treatment was well tolerated, but median OS did not reach improvement specified by protocol compared to historical control, indicating that the combination of standard RT with TMZ and MGd did not achieve a significant survival advantage.

  4. Prognostic value of the extent of resection in supratentorial WHO grade II astrocytomas stratified for IDH1 mutation status: a single-center volumetric analysis.

    PubMed

    Jungk, Christine; Scherer, Moritz; Mock, Andreas; Capper, David; Radbruch, Alexander; von Deimling, Andreas; Bendszus, Martin; Herold-Mende, Christel; Unterberg, Andreas

    2016-09-01

    Current evidence supports a maximized extent of resection (EOR) in low-grade gliomas (LGG), regardless of different histological subtypes and molecular markers. We therefore evaluated the prognostic impact of extensive, mainly intraoperative (i)MRI-guided surgery in low-grade astrocytomas stratified for IDH1 mutation status. Retrospective assessment of 46 consecutive cases of newly diagnosed supratentorial WHO grade II astrocytomas treated during the last decade was performed. IDH1 mutation status was obtained for all patients. Volumetric analysis of tumor volumes was performed pre-, intra-, early postoperatively and at first follow-up. Survival analysis was conducted with uni-and multivariate regression models implementing clinical parameters and continuous volumetric variables. Median EOR was 90.4 % (range 17.5-100 %) and was increased to 94.9 % (range 34.8-100 %) in iMRI-guided resections (n = 33). A greater EOR was prognostic for increased progression-free survival (HR 0.23, p = 0.031) and time to re-intervention (TTR) (HR 0.23, p = 0.03). In IDH1 mutant patients, smaller residual tumor volumes were associated with increased TTR (HR 1.01, p = 0.03). IDH1 mutation (38/46 cases) was an independent positive prognosticator for overall survival (OS) in multivariate analysis (HR 0.09, p = 0.002), while extensive surgery had limited impact upon OS. In a subgroup of patients with ≥40 % EOR (n = 39), however, initial and residual tumor volumes were prognostic for OS (HR 1.03, p = 0.005 and HR 1.08, p = 0.007, respectively), persistent to adjustment for IDH1. No association between EOR and neurologic morbidity was found. In this analysis of low-grade astrocytomas stratified for IDH1, extensive tumor resections were prognostic for progression and TTR and, in patients with ≥40 % EOR, for OS.

  5. Rationale and Design of a Phase I Clinical Trial to Evaluate HSV G207 Alone or with a Single Radiation Dose in Children with Progressive or Recurrent Malignant Supratentorial Brain Tumors.

    PubMed

    Waters, Alicia M; Johnston, James M; Reddy, Alyssa T; Fiveash, John; Madan-Swain, Avi; Kachurak, Kara; Bag, Asim K; Gillespie, G Yancey; Markert, James M; Friedman, Gregory K

    2017-02-24

    Primary central nervous system tumors are the most common solid neoplasm of childhood and the leading cause of cancer related death in pediatric patients. Survival rates for children with malignant supratentorial brain tumors are poor despite aggressive treatment with combinations of surgery, radiation, and chemotherapy; and survivors often suffer from damaging lifelong sequelae from current therapies. Novel innovative treatments are greatly needed. One promising new approach is the use of a genetically engineered, conditionally replicating herpes simplex virus (HSV) that has shown tumor specific tropism and potential efficacy in the treatment of malignant brain tumors. G207 is a genetically engineered HSV-1 lacking genes essential for replication in normal brain cells. Safety has been established in preclinical investigations involving intracranial inoculation in the highly HSV-sensitive owl monkey (Aotus nancymai), and in three adult phase I trials in recurrent/progressive high-grade gliomas. No dose-limiting toxicities were seen in the adult studies and a maximum tolerated dose was not reached. Approximately half of the 35 treated adults had radiographic or neuropathologic evidence of response at a minimum of one time point. Preclinical studies in pediatric brain tumor models indicate that a variety of pediatric tumor types are highly sensitive to killing by G207. This clinical protocol outlines a first in human children study of intratumoral inoculation of an oncolytic virus via catheters placed directly into recurrent or progressive supratentorial malignant tumors.

  6. Rationale and Design of a Phase 1 Clinical Trial to Evaluate HSV G207 Alone or with a Single Radiation Dose in Children with Progressive or Recurrent Malignant Supratentorial Brain Tumors.

    PubMed

    Waters, Alicia M; Johnston, James M; Reddy, Alyssa T; Fiveash, John; Madan-Swain, Avi; Kachurak, Kara; Bag, Asim K; Gillespie, G Yancey; Markert, James M; Friedman, Gregory K

    2017-03-01

    Primary central nervous system tumors are the most common solid neoplasm of childhood and the leading cause of cancer-related death in pediatric patients. Survival rates for children with malignant supratentorial brain tumors are poor despite aggressive treatment with combinations of surgery, radiation, and chemotherapy, and survivors often suffer from damaging lifelong sequelae from current therapies. Novel innovative treatments are greatly needed. One promising new approach is the use of a genetically engineered, conditionally replicating herpes simplex virus (HSV) that has shown tumor-specific tropism and potential efficacy in the treatment of malignant brain tumors. G207 is a genetically engineered HSV-1 lacking genes essential for replication in normal brain cells. Safety has been established in preclinical investigations involving intracranial inoculation in the highly HSV-sensitive owl monkey (Aotus nancymai), and in three adult phase 1 trials in recurrent/progressive high-grade gliomas. No dose-limiting toxicities were seen in the adult studies and a maximum tolerated dose was not reached. Approximately half of the 35 treated adults had radiographic or neuropathologic evidence of response at a minimum of one time point. Preclinical studies in pediatric brain tumor models indicate that a variety of pediatric tumor types are highly sensitive to killing by G207. This clinical protocol outlines a first in human children study of intratumoral inoculation of an oncolytic virus via catheters placed directly into recurrent or progressive supratentorial malignant tumors.

  7. Longitudinal changes in cortical thickness in autism and typical development.

    PubMed

    Zielinski, Brandon A; Prigge, Molly B D; Nielsen, Jared A; Froehlich, Alyson L; Abildskov, Tracy J; Anderson, Jeffrey S; Fletcher, P Thomas; Zygmunt, Kristen M; Travers, Brittany G; Lange, Nicholas; Alexander, Andrew L; Bigler, Erin D; Lainhart, Janet E

    2014-06-01

    The natural history of brain growth in autism spectrum disorders remains unclear. Cross-sectional studies have identified regional abnormalities in brain volume and cortical thickness in autism, although substantial discrepancies have been reported. Preliminary longitudinal studies using two time points and small samples have identified specific regional differences in cortical thickness in the disorder. To clarify age-related trajectories of cortical development, we examined longitudinal changes in cortical thickness within a large mixed cross-sectional and longitudinal sample of autistic subjects and age- and gender-matched typically developing controls. Three hundred and forty-five magnetic resonance imaging scans were examined from 97 males with autism (mean age = 16.8 years; range 3-36 years) and 60 males with typical development (mean age = 18 years; range 4-39 years), with an average interscan interval of 2.6 years. FreeSurfer image analysis software was used to parcellate the cortex into 34 regions of interest per hemisphere and to calculate mean cortical thickness for each region. Longitudinal linear mixed effects models were used to further characterize these findings and identify regions with between-group differences in longitudinal age-related trajectories. Using mean age at time of first scan as a reference (15 years), differences were observed in bilateral inferior frontal gyrus, pars opercularis and pars triangularis, right caudal middle frontal and left rostral middle frontal regions, and left frontal pole. However, group differences in cortical thickness varied by developmental stage, and were influenced by IQ. Differences in age-related trajectories emerged in bilateral parietal and occipital regions (postcentral gyrus, cuneus, lingual gyrus, pericalcarine cortex), left frontal regions (pars opercularis, rostral middle frontal and frontal pole), left supramarginal gyrus, and right transverse temporal gyrus, superior parietal lobule, and

  8. Organization of a Large-Scale Cortical Network

    DTIC Science & Technology

    1989-01-01

    potentiation of the dcntatc mossy fiber synapscs on hippocampal CA3 pyramidal cells, and interactions between this short-term potentiation and long-term...Larson, J., and Lynch, G. Mossy fiber potentiation involves different substrates than those mediating LTP. (submitted) 24. Jung, M.W., Larson, J., and...to be visible as a definable fiber tract. Theta burst stimulation to the LOT induced LTP in 16/48 slices examined, a proportion much lower than that

  9. Computer-aided system for measuring the mandibular cortical width on panoramic radiographs in osteoporosis diagnosis

    NASA Astrophysics Data System (ADS)

    Arifin, Agus Zainal; Asano, Akira; Taguchi, Akira; Nakamoto, Takashi; Ohtsuka, Masahiko; Tanimoto, Keiji

    2005-04-01

    Osteoporotic fractures are associated with substantial morbidity, increased medical cost and high mortality risk. Several equipments of bone assessment have been developed to identify individuals, especially postmenopausal women, with high risk of osteoporotic fracture; however, a large segment of women with low skeletal bone mineral density (BMD), namely women with high risk of osteoporotic fractures, cannot be identified sufficiently because osteoporosis is asymptomatic. Recent studies have been demonstrating that mandibular inferior cortical width manually measured on panoramic radiographs may be useful for the identification of women with low BMD. Automatic measurement of cortical width may enable us to identify a large number of asymptomatic women with low BMD. The purpose of this study was to develop a computer-aided system for measuring the mandibular cortical width on panoramic radiographs. Initially, oral radiologists determined the region of interest based on the position of mental foramen. Some enhancing image techniques were applied so as to measure the cortical width at the best point. Panoramic radiographs of 100 women who had BMD assessments of the lumbar spine and femoral neck were used to confirm the efficacy of our new system. Cortical width measured with our system was compared with skeletal BMD. There were significant correlation between cortical width measured with our system and skeletal BMD. These correlations were similar with those between cortical width manually measured by the dentist and skeletal BMD. Our results suggest that our new system may be useful for mass screening of osteoporosis.

  10. Convergence and divergence are mostly reciprocated properties of the connections in the network of cortical areas.

    PubMed

    Négyessy, László; Nepusz, Tamás; Zalányi, László; Bazsó, Fülöp

    2008-10-22

    Cognition is based on the integrated functioning of hierarchically organized cortical processing streams in a manner yet to be clarified. Because integration fundamentally depends on convergence and the complementary notion of divergence of the neuronal connections, we analysed integration by measuring the degree of convergence/divergence through the connections in the network of cortical areas. By introducing a new index, we explored the complementary convergent and divergent nature of connectional reciprocity and delineated the backward and forward cortical sub-networks for the first time. Integrative properties of the areas defined by the degree of convergence/divergence through their afferents and efferents exhibited distinctive characteristics at different levels of the cortical hierarchy. Areas previously identified as hubs exhibit information bottleneck properties. Cortical networks largely deviate from random graphs where convergence and divergence are balanced at low reciprocity level. In the cortex, which is dominated by reciprocal connections, balance appears only by further increasing the number of reciprocal connections. The results point to the decisive role of the optimal number and placement of reciprocal connections in large-scale cortical integration. Our findings also facilitate understanding of the functional interactions between the cortical areas and the information flow or its equivalents in highly recurrent natural and artificial networks.

  11. Cortical thickness and brain volumetric analysis in body dysmorphic disorder

    PubMed Central

    Madsen, Sarah K.; Zai, Alex; Pirnia, Tara; Arienzo, Donatello; Zhan, Liang; Moody, Teena D.; Thompson, Paul M.; Feusner, Jamie D.

    2015-01-01

    Individuals with body dysmorphic disorder (BDD) suffer from preoccupations with perceived defects in physical appearance, causing severe distress and disability. Although BDD affects 1-2% of the population, the neurobiology is not understood. Discrepant results in previous volumetric studies may be due to small sample sizes, and no study has investigated cortical thickness in BDD. The current study is the largest neuroimaging analysis of BDD. Participants included 49 medication-free, right-handed individuals with DSM-IV BDD and 44 healthy controls matched by age, sex, and education. Using high-resolution T1-weighted magnetic resonance imaging, we computed vertex-wise gray matter (GM) thickness on the cortical surface and GM volume using voxel-based morphometry. We also computed volumes in cortical and subcortical regions of interest. In addition to group comparisons, we investigated associations with symptom severity, insight, and anxiety within the BDD group. In BDD, greater anxiety was significantly associated with thinner GM in the left superior temporal cortex and greater GM volume in the right caudate nucleus. There were no significant differences in cortical thickness, GM volume, or volumes in regions of interest between BDD and control subjects. Subtle associations with clinical symptoms may characterize brain morphometric patterns in BDD, rather than large group differences in brain structure. PMID:25797401

  12. Cortical network architecture for context processing in primate brain

    PubMed Central

    Chao, Zenas C; Nagasaka, Yasuo; Fujii, Naotaka

    2015-01-01

    Context is information linked to a situation that can guide behavior. In the brain, context is encoded by sensory processing and can later be retrieved from memory. How context is communicated within the cortical network in sensory and mnemonic forms is unknown due to the lack of methods for high-resolution, brain-wide neuronal recording and analysis. Here, we report the comprehensive architecture of a cortical network for context processing. Using hemisphere-wide, high-density electrocorticography, we measured large-scale neuronal activity from monkeys observing videos of agents interacting in situations with different contexts. We extracted five context-related network structures including a bottom-up network during encoding and, seconds later, cue-dependent retrieval of the same network with the opposite top-down connectivity. These findings show that context is represented in the cortical network as distributed communication structures with dynamic information flows. This study provides a general methodology for recording and analyzing cortical network neuronal communication during cognition. DOI: http://dx.doi.org/10.7554/eLife.06121.001 PMID:26416139

  13. Cortical thickness and brain volumetric analysis in body dysmorphic disorder.

    PubMed

    Madsen, Sarah K; Zai, Alex; Pirnia, Tara; Arienzo, Donatello; Zhan, Liang; Moody, Teena D; Thompson, Paul M; Feusner, Jamie D

    2015-04-30

    Individuals with body dysmorphic disorder (BDD) suffer from preoccupations with perceived defects in physical appearance, causing severe distress and disability. Although BDD affects 1-2% of the population, the neurobiology is not understood. Discrepant results in previous volumetric studies may be due to small sample sizes, and no study has investigated cortical thickness in BDD. The current study is the largest neuroimaging analysis of BDD. Participants included 49 medication-free, right-handed individuals with DSM-IV BDD and 44 healthy controls matched by age, sex, and education. Using high-resolution T1-weighted magnetic resonance imaging, we computed vertex-wise gray matter (GM) thickness on the cortical surface and GM volume using voxel-based morphometry. We also computed volumes in cortical and subcortical regions of interest. In addition to group comparisons, we investigated associations with symptom severity, insight, and anxiety within the BDD group. In BDD, greater anxiety was significantly associated with thinner GM in the left superior temporal cortex and greater GM volume in the right caudate nucleus. There were no significant differences in cortical thickness, GM volume, or volumes in regions of interest between BDD and control subjects. Subtle associations with clinical symptoms may characterize brain morphometric patterns in BDD, rather than large group differences in brain structure. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Focal Cortical Dysplasia (FCD) lesion analysis with complex diffusion approach.

    PubMed

    Rajan, Jeny; Kannan, K; Kesavadas, C; Thomas, Bejoy

    2009-10-01

    Identification of Focal Cortical Dysplasia (FCD) can be difficult due to the subtle MRI changes. Though sequences like FLAIR (fluid attenuated inversion recovery) can detect a large majority of these lesions, there are smaller lesions without signal changes that can easily go unnoticed by the naked eye. The aim of this study is to improve the visibility of focal cortical dysplasia lesions in the T1 weighted brain MRI images. In the proposed method, we used a complex diffusion based approach for calculating the FCD affected areas. Based on the diffused image and thickness map, a complex map is created. From this complex map; FCD areas can be easily identified. MRI brains of 48 subjects selected by neuroradiologists were given to computer scientists who developed the complex map for identifying the cortical dysplasia. The scientists were blinded to the MRI interpretation result of the neuroradiologist. The FCD could be identified in all the patients in whom surgery was done, however three patients had false positive lesions. More lesions were identified in patients in whom surgery was not performed and lesions were seen in few of the controls. These were considered as false positive. This computer aided detection technique using complex diffusion approach can help detect focal cortical dysplasia in patients with epilepsy.

  15. Hamilton-Jacobi skeleton on cortical surfaces.

    PubMed

    Shi, Y; Thompson, P M; Dinov, I; Toga, A W

    2008-05-01

    In this paper, we propose a new method to construct graphical representations of cortical folding patterns by computing skeletons on triangulated cortical surfaces. In our approach, a cortical surface is first partitioned into sulcal and gyral regions via the solution of a variational problem using graph cuts, which can guarantee global optimality. After that, we extend the method of Hamilton-Jacobi skeleton [1] to subsets of triangulated surfaces, together with a geometrically intuitive pruning process that can trade off between skeleton complexity and the completeness of representing folding patterns. Compared with previous work that uses skeletons of 3-D volumes to represent sulcal patterns, the skeletons on cortical surfaces can be easily decomposed into branches and provide a simpler way to construct graphical representations of cortical morphometry. In our experiments, we demonstrate our method on two different cortical surface models, its ability of capturing major sulcal patterns and its application to compute skeletons of gyral regions.

  16. Circadian regulation of human cortical excitability

    PubMed Central

    Ly, Julien Q. M.; Gaggioni, Giulia; Chellappa, Sarah L.; Papachilleos, Soterios; Brzozowski, Alexandre; Borsu, Chloé; Rosanova, Mario; Sarasso, Simone; Middleton, Benita; Luxen, André; Archer, Simon N.; Phillips, Christophe; Dijk, Derk-Jan; Maquet, Pierre; Massimini, Marcello; Vandewalle, Gilles

    2016-01-01

    Prolonged wakefulness alters cortical excitability, which is essential for proper brain function and cognition. However, besides prior wakefulness, brain function and cognition are also affected by circadian rhythmicity. Whether the regulation of cognition involves a circadian impact on cortical excitability is unknown. Here, we assessed cortical excitability from scalp electroencephalography (EEG) responses to transcranial magnetic stimulation in 22 participants during 29 h of wakefulness under constant conditions. Data reveal robust circadian dynamics of cortical excitability that are strongest in those individuals with highest endocrine markers of circadian amplitude. In addition, the time course of cortical excitability correlates with changes in EEG synchronization and cognitive performance. These results demonstrate that the crucial factor for cortical excitability, and basic brain function in general, is the balance between circadian rhythmicity and sleep need, rather than sleep homoeostasis alone. These findings have implications for clinical applications such as non-invasive brain stimulation in neurorehabilitation. PMID:27339884

  17. Disorders of cortical formation: MR imaging features.

    PubMed

    Abdel Razek, A A K; Kandell, A Y; Elsorogy, L G; Elmongy, A; Basett, A A

    2009-01-01

    The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally describe the main MR imaging features of these disorders. Disorders of cortical formation are classified according to the embryologic stage of the cerebral cortex at which the abnormality occurred. MR imaging shows diminished cortical thickness and sulcation in microcephaly, enlarged dysplastic cortex in hemimegalencephaly, and ipsilateral focal cortical thickening with radial hyperintense bands in focal cortical dysplasia. MR imaging detects smooth brain in classic lissencephaly, the nodular cortex with cobblestone cortex with congenital muscular dystrophy, and the ectopic position of the gray matter with heterotopias. MR imaging can detect polymicrogyria and related syndromes as well as the types of schizencephaly. We concluded that MR imaging is essential to demonstrate the morphology, distribution, and extent of different disorders of cortical formation as well as the associated anomalies and related syndromes.

  18. Inhibitory Circuits in Cortical Layer 5

    PubMed Central

    Naka, Alexander; Adesnik, Hillel

    2016-01-01

    Inhibitory neurons play a fundamental role in cortical computation and behavior. Recent technological advances, such as two photon imaging, targeted in vivo recording, and molecular profiling, have improved our understanding of the function and diversity of cortical interneurons, but for technical reasons most work has been directed towards inhibitory neurons in the superficial cortical layers. Here we review current knowledge specifically on layer 5 (L5) inhibitory microcircuits, which play a critical role in controlling cortical output. We focus on recent work from the well-studied rodent barrel cortex, but also draw on evidence from studies in primary visual cortex and other cortical areas. The diversity of both deep inhibitory neurons and their pyramidal cell targets make this a challenging but essential area of study in cortical computation and sensory processing. PMID:27199675

  19. Cortical microtubule rearrangements and cell wall patterning

    PubMed Central

    Oda, Yoshihisa

    2015-01-01

    Plant cortical microtubules, which form a highly ordered array beneath the plasma membrane, play essential roles in determining cell shape and function by directing the arrangement of cellulosic and non-cellulosic compounds on the cell surface. Interphase transverse arrays of cortical microtubules self-organize through their dynamic instability and inter-microtubule interactions, and by branch-form microtubule nucleation and severing. Recent studies revealed that distinct spatial signals including ROP GTPase, cellular geometry, and mechanical stress regulate the behavior of cortical microtubules at the subcellular and supercellular levels, giving rise to dramatic rearrangements in the cortical microtubule array in response to internal and external cues. Increasing evidence indicates that negative regulators of microtubules also contribute to the rearrangement of the cortical microtubule array. In this review, I summarize recent insights into how the rearrangement of the cortical microtubule array leads to proper, flexible cell wall patterning. PMID:25904930

  20. MR appearance of distal femoral cortical irregularity (cortical desmoid)

    SciTech Connect

    Suh, Jin-Suck; Cho, Jae-Hyun; Shin, Kyoo-Ho

    1996-03-01

    Our goal was to describe the MR appearance of distal femoral cortical irregularity (DFCI). With plain radiographs and MR images of 100 knees, the presence of DFCIs was determined, and the shapes of DFCIs were classified into three subgroups: concave, convex, and divergent cortical shapes. Radiographic and MR shapes of DFCIs were compared. DFCIs were shown in various shapes on both the radiographs and the MR images. Forty-four DFCIs were found both on radiograph and by MR image. An additional 14 DFCIs were identifiable only on MR images. However, the majority of DFCIs showed an association between radiographic and MR shapes. MRI revealed that all 58 DFCIs were located at the attachment site of the media gastrocnemius muscle. DFCIs were enhanced in three of the four patients who underwent postcontrast MR study. A good understanding of radiographic and MR findings of the DFCI may be of great help in the differential diagnosis of distal femoral lesions. 16 refs., 6 figs., 1 tab.

  1. Posttraumatic cortical defect of femur.

    PubMed

    Nadarajah, Jeyaseelan; Srivastava, Deep N; Malhotra, Rajesh; Palaniswamy, Aravindh

    2013-01-01

    Posttraumatic cortical defect of bone is a rare entity which occurs in a maturing skeleton following green stick or torus fracture. Most of the cases are asymptomatic and they are detected incidentally on radiograph. These lesions usually require no treatment. However, the appearance of these lesions can mimic various pathological conditions affecting bone. Knowledge about this entity is important as it avoids unnecessary investigations. We present this case as the occurrence of this entity in femur is very rare and the child was symptomatic.

  2. Cortical rewiring and information storage

    NASA Astrophysics Data System (ADS)

    Chklovskii, D. B.; Mel, B. W.; Svoboda, K.

    2004-10-01

    Current thinking about long-term memory in the cortex is focused on changes in the strengths of connections between neurons. But ongoing structural plasticity in the adult brain, including synapse formation/elimination and remodelling of axons and dendrites, suggests that memory could also depend on learning-induced changes in the cortical `wiring diagram'. Given that the cortex is sparsely connected, wiring plasticity could provide a substantial boost in storage capacity, although at a cost of more elaborate biological machinery and slower learning.

  3. Imprinting and Recalling Cortical Ensembles

    PubMed Central

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S.; Yuste, Rafael

    2017-01-01

    Neuronal ensembles are coactive groups of neurons that may represent emergent building blocks of neural circuits. They could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations in visual cortex of awake mice generates artificially induced ensembles which recur spontaneously after being imprinted and do not disrupt preexistent ones. Moreover, imprinted ensembles can be recalled by single cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. PMID:27516599

  4. Communication and wiring in the cortical connectome

    PubMed Central

    Budd, Julian M. L.; Kisvárday, Zoltán F.

    2012-01-01

    In cerebral cortex, the huge mass of axonal wiring that carries information between near and distant neurons is thought to provide the neural substrate for cognitive and perceptual function. The goal of mapping the connectivity of cortical axons at different spatial scales, the cortical connectome, is to trace the paths of information flow in cerebral cortex. To appreciate the relationship between the connectome and cortical function, we need to discover the nature and purpose of the wiring principles underlying cortical connectivity. A popular explanation has been that axonal length is strictly minimized both within and between cortical regions. In contrast, we have hypothesized the existence of a multi-scale principle of cortical wiring where to optimize communication there is a trade-off between spatial (construction) and temporal (routing) costs. Here, using recent evidence concerning cortical spatial networks we critically evaluate this hypothesis at neuron, local circuit, and pathway scales. We report three main conclusions. First, the axonal and dendritic arbor morphology of single neocortical neurons may be governed by a similar wiring principle, one that balances the conservation of cellular material and conduction delay. Second, the same principle may be observed for fiber tracts connecting cortical regions. Third, the absence of sufficient local circuit data currently prohibits any meaningful assessment of the hypothesis at this scale of cortical organization. To avoid neglecting neuron and microcircuit levels of cortical organization, the connectome framework should incorporate more morphological description. In addition, structural analyses of temporal cost for cortical circuits should take account of both axonal conduction and neuronal integration delays, which appear mostly of the same order of magnitude. We conclude the hypothesized trade-off between spatial and temporal costs may potentially offer a powerful explanation for cortical wiring patterns

  5. [Posterior cortical atrophy (Benson-syndrome)].

    PubMed

    Rózsa, Anikó; Szilvássy, Ildikó; Kovács, Krisztina; Boór, Krisztina; Gács, Gyula

    2010-01-30

    We present the characteristics of posterior cortical atrophy--a very rare cortical dementia--in a 69 year old woman's case. Our patient's symptoms began with a visual problem which was initially explained by ophthalmological disorder. After neurological exam visual agnosia was diagnosed apart from other cognitive disorder (alexia without agraphia, acalculia, prosopagnosia, constructional disorder, clock-time recognition disorder, dressing apraxia, visuospatial disorientation). The brain MRI showed bilateral asymmetric parieto-occipital atrophy which is characteristic of posterior cortical atrophy.

  6. Cortical Tremor (CT) with coincident orthostatic movements.

    PubMed

    Termsarasab, Pichet; Frucht, Steven J

    2015-01-01

    Cortical tremor (CT) is a form of cortical reflex myoclonus that can mimic essential tremor (ET). Clinical features that are helpful in distinguishing CT from ET are the irregular and jerky appearance of the movements. We report two patients with CT with coexisting orthostatic movements, either orthostatic tremor (OT) or myoclonus, who experienced functional improvement in both cortical myoclonus and orthostatic movements when treated with levetiracetam.

  7. Cortical surface area and cortical thickness in the precuneus of adult humans.

    PubMed

    Bruner, E; Román, F J; de la Cuétara, J M; Martin-Loeches, M; Colom, R

    2015-02-12

    The precuneus has received considerable attention in the last decade, because of its cognitive functions, its role as a central node of the brain networks, and its involvement in neurodegenerative processes. Paleoneurological studies suggested that form changes in the deep parietal areas represent a major character associated with the origin of the modern human brain morphology. A recent neuroanatomical survey based on shape analysis suggests that the proportions of the precuneus are also a determinant source of overall brain geometrical differences among adult individuals, influencing the brain spatial organization. Here, we evaluate the variation of cortical thickness and cortical surface area of the precuneus in a sample of adult humans, and their relation with geometry and cognition. Precuneal thickness and surface area are not correlated. There is a marked individual variation. The right precuneus is thinner and larger than the left one, but there are relevant fluctuating asymmetries, with only a modest correlation between the hemispheres. Males have a thicker cortex but differences in cortical area are not significant between sexes. The surface area of the precuneus shows a positive allometry with the brain surface area, although the correlation is modest. The dilation/contraction of the precuneus, described as a major factor of variability within adult humans, is associated with absolute increase/decrease of its surface, but not with variation in thickness. Precuneal thickness, precuneal surface area and precuneal morphology are not correlated with psychological factors such as intelligence, working memory, attention control, and processing speed, stressing further possible roles of this area in supporting default mode functions. Beyond gross morphology, the processes underlying the large phenotypic variation of the precuneus must be further investigated through specific cellular analyses, aimed at considering differences in cellular size, density

  8. Chronic imaging of cortical sensory map dynamics using a genetically encoded calcium indicator.

    PubMed

    Minderer, Matthias; Liu, Wenrui; Sumanovski, Lazar T; Kügler, Sebastian; Helmchen, Fritjof; Margolis, David J

    2012-01-01

    In vivo optical imaging can reveal the dynamics of large-scale cortical activity, but methods for chronic recording are limited. Here we present a technique for long-term investigation of cortical map dynamics using wide-field ratiometric fluorescence imaging of the genetically encoded calcium indicator (GECI) Yellow Cameleon 3.60. We find that wide-field GECI signals report sensory-evoked activity in anaesthetized mouse somatosensory cortex with high sensitivity and spatiotemporal precision, and furthermore, can be measured repeatedly in separate imaging sessions over multiple weeks. This method opens new possibilities for the longitudinal study of stability and plasticity of cortical sensory representations.

  9. Cortical auditory disorders: clinical and psychoacoustic features.

    PubMed Central

    Mendez, M F; Geehan, G R

    1988-01-01

    The symptoms of two patients with bilateral cortical auditory lesions evolved from cortical deafness to other auditory syndromes: generalised auditory agnosia, amusia and/or pure word deafness, and a residual impairment of temporal sequencing. On investigation, both had dysacusis, absent middle latency evoked responses, acoustic errors in sound recognition and matching, inconsistent auditory behaviours, and similarly disturbed psychoacoustic discrimination tasks. These findings indicate that the different clinical syndromes caused by cortical auditory lesions form a spectrum of related auditory processing disorders. Differences between syndromes may depend on the degree of involvement of a primary cortical processing system, the more diffuse accessory system, and possibly the efferent auditory system. Images PMID:2450968

  10. Dual Cortical Plasticity After Spinal Cord Injury.

    PubMed

    Humanes-Valera, Desire; Foffani, Guglielmo; Alonso-Calviño, Elena; Fernández-López, Elena; Aguilar, Juan

    2017-05-01

    During cortical development, plasticity reflects the dynamic equilibrium between increasing and decreasing functional connectivity subserved by synaptic sprouting and pruning. After adult cortical deafferentation, plasticity seems to be dominated by increased functional connectivity, leading to the classical expansive reorganization from the intact to the deafferented cortex. In contrast, here we show a striking "decrease" in the fast cortical responses to high-intensity forepaw stimulation 1-3 months after complete thoracic spinal cord transection, as evident in both local field potentials and intracellular in vivo recordings. Importantly, this decrease in fast cortical responses co-exists with an "increase" in cortical activation over slower post-stimulus timescales, as measured by an increased forepaw-to-hindpaw propagation of stimulus-triggered cortical up-states, as well as by the enhanced slow sustained depolarization evoked by high-frequency forepaw stimuli in the deafferented hindpaw cortex. This coincidence of diminished fast cortical responses and enhanced slow cortical activation offers a dual perspective of adult cortical plasticity after spinal cord injury. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  11. Cortical organization in the Etruscan shrew (Suncus etruscus).

    PubMed

    Roth-Alpermann, Claudia; Anjum, Farzana; Naumann, Robert; Brecht, Michael

    2010-11-01

    Cortical organization in the Etruscan shrew is of comparative interest because of its small size and because the Etruscan shrew is an amazing tactile hunter. Here we investigated cortical organization in Etruscan shrews by electrophysiological mapping. We developed an anesthesia protocol for this very small mammal in which we combined massive application of local anesthesia, very slow induction of general anesthesia, and passive cooling. Under this anesthesia regime, we characterized auditory, visual, and somatosensory cortical responses. We found that large parts of shrew cortex respond to such stimuli. Of the responsive sites, a small fraction (∼14%) responded to visual stimuli in a caudally located region. Another small fraction of sites (∼11%) responded to auditory stimuli in a centrally located region. The majority of sites (∼75%) responded to tactile stimuli. We identified two topographically organized somatosensory areas with small receptive fields referred to as putative primary somatosensory cortex and putative secondary somatosensory cortex. In a posterior-lateral region that partially overlaps with piriform cortex, we observed large somatosensory receptive fields and often polysensory responses. In an anterior-lateral region that partially overlaps with piriform cortex, we observed large unimodal somatosensory receptive fields. Our findings demonstrate a remarkable degree of tactile specialization in Etruscan shrew cortex.

  12. Global Neuromagnetic Cortical Fields Have Non-Zero Velocity

    PubMed Central

    Alexander, David M.; Nikolaev, Andrey R.; Jurica, Peter; Zvyagintsev, Mikhail; Mathiak, Klaus; van Leeuwen, Cees

    2016-01-01

    Globally coherent patterns of phase can be obscured by analysis techniques that aggregate brain activity measures across-trials, whether prior to source localization or for estimating inter-areal coherence. We analyzed, at single-trial level, whole head MEG recorded during an observer-triggered apparent motion task. Episodes of globally coherent activity occurred in the delta, theta, alpha and beta bands of the signal in the form of large-scale waves, which propagated with a variety of velocities. Their mean speed at each frequency band was proportional to temporal frequency, giving a range of 0.06 to 4.0 m/s, from delta to beta. The wave peaks moved over the entire measurement array, during both ongoing activity and task-relevant intervals; direction of motion was more predictable during the latter. A large proportion of the cortical signal, measurable at the scalp, exists as large-scale coherent motion. We argue that the distribution of observable phase velocities in MEG is dominated by spatial filtering considerations in combination with group velocity of cortical activity. Traveling waves may index processes involved in global coordination of cortical activity. PMID:26953886

  13. Intracranial periventricular supratentorial intraparenchymal schwannoma

    PubMed Central

    Gupta, Anshul; Sharma, Divyam; Dhillon, Gurupal Singh; Chhabra, Satnam Singh

    2016-01-01

    Background: Intraparenchymal schwannomas in the central nervous system are very rare. Because most of these are benign, complete excision is the treatment of choice. Further, their radiological findings are difficult to differentiate from glioma. Because Schwann cells are not indigenous to cerebral parenchyma, a lot of speculation has been attached to their origin. Case Description: We report one such rare case of a 17-year-old male who presented to us with a history of headache and vomiting. Neuroradiological findings were suggestive of left temporoparietal solid cystic lesion with enhancement of solid component, suggestive of high grade glioma. Conclusion: Intraoperative impression was that of a low-grade glioma but histopathological features were represented as schwannoma. PMID:28144475

  14. Pusher syndrome: its cortical correlate.

    PubMed

    Baier, Bernhard; Janzen, Jelena; Müller-Forell, Wibke; Fechir, Marcel; Müller, Notger; Dieterich, Marianne

    2012-02-01

    Unilateral stroke can lead to a disorder of postural balance that manifests as a pushing away toward the contralesional side. It is called "pusher syndrome" (PS). The aims of this study were first to assess the anatomical cortical regions that induce PS and second to clarify whether tilt of the subjective visual vertical (SVV)--a sign of vestibular otolith dysfunction--is associated with PS. Sixty-six patients with acute unilateral strokes (28 left-sided lesions, 38 right-sided lesions) were tested for PS, for tilts of the SVV, for hemineglect and for the anatomical lesion site by magnetic resonance imaging (MRI)-based voxelwise lesion-behavior mapping analysis. Our data indicated no significant voxels; however, there was a trend towards an association between lesions of the posterior part of the insula, the operculum and the superior temporal gyrus--key areas of the multisensory vestibular cortical network--and the extent of pushing in patients with right-sided lesions, whereas the rather anterior part of the insula, the operculum as well as the internal capsule reaching to the lateral thalamus seemed to be involved in PS in left-sided lesion patients. These data might point toward a link between the systems responsible for postural control and for processing vestibular otolith information. These findings indicate that vestibular information might be fundamental in right-sided lesion patients for maintaining body posture in space.

  15. Cortical control of facial expression.

    PubMed

    Müri, René M

    2016-06-01

    The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system.

  16. Cortical Specializations Underlying Fast Computations.

    PubMed

    Volgushev, Maxim

    2016-04-01

    The time course of behaviorally relevant environmental events sets temporal constraints on neuronal processing. How does the mammalian brain make use of the increasingly complex networks of the neocortex, while making decisions and executing behavioral reactions within a reasonable time? The key parameter determining the speed of computations in neuronal networks is a time interval that neuronal ensembles need to process changes at their input and communicate results of this processing to downstream neurons. Theoretical analysis identified basic requirements for fast processing: use of neuronal populations for encoding, background activity, and fast onset dynamics of action potentials in neurons. Experimental evidence shows that populations of neocortical neurons fulfil these requirements. Indeed, they can change firing rate in response to input perturbations very quickly, within 1 to 3 ms, and encode high-frequency components of the input by phase-locking their spiking to frequencies up to 300 to 1000 Hz. This implies that time unit of computations by cortical ensembles is only few, 1 to 3 ms, which is considerably faster than the membrane time constant of individual neurons. The ability of cortical neuronal ensembles to communicate on a millisecond time scale allows for complex, multiple-step processing and precise coordination of neuronal activity in parallel processing streams, while keeping the speed of behavioral reactions within environmentally set temporal constraints.

  17. Cortical thickness in untreated transsexuals.

    PubMed

    Zubiaurre-Elorza, Leire; Junque, Carme; Gómez-Gil, Esther; Segovia, Santiago; Carrillo, Beatriz; Rametti, Giuseppina; Guillamon, Antonio

    2013-12-01

    Sex differences in cortical thickness (CTh) have been extensively investigated but as yet there are no reports on CTh in transsexuals. Our aim was to determine whether the CTh pattern in transsexuals before hormonal treatment follows their biological sex or their gender identity. We performed brain magnetic resonance imaging on 94 subjects: 24 untreated female-to-male transsexuals (FtMs), 18 untreated male-to-female transsexuals (MtFs), and 29 male and 23 female controls in a 3-T TIM-TRIO Siemens scanner. T1-weighted images were analyzed to obtain CTh and volumetric subcortical measurements with FreeSurfer software. CTh maps showed control females have thicker cortex than control males in the frontal and parietal regions. In contrast, males have greater right putamen volume. FtMs had a similar CTh to control females and greater CTh than males in the parietal and temporal cortices. FtMs had larger right putamen than females but did not differ from males. MtFs did not differ in CTh from female controls but had greater CTh than control males in the orbitofrontal, insular, and medial occipital regions. In conclusion, FtMs showed evidence of subcortical gray matter masculinization, while MtFs showed evidence of CTh feminization. In both types of transsexuals, the differences with respect to their biological sex are located in the right hemisphere.

  18. Brief anesthesia, but not voluntary locomotion, significantly alters cortical temperature

    PubMed Central

    Shirey, Michael J.; Kudlik, D'Anne E.; Huo, Bing-Xing; Greene, Stephanie E.; Drew, Patrick J.

    2015-01-01

    Changes in brain temperature can alter electrical properties of neurons and cause changes in behavior. However, it is not well understood how behaviors, like locomotion, or experimental manipulations, like anesthesia, alter brain temperature. We implanted thermocouples in sensorimotor cortex of mice to understand how cortical temperature was affected by locomotion, as well as by brief and prolonged anesthesia. Voluntary locomotion induced small (∼0.1°C) but reliable increases in cortical temperature that could be described using a linear convolution model. In contrast, brief (90-s) exposure to isoflurane anesthesia depressed cortical temperature by ∼2°C, which lasted for up to 30 min after the cessation of anesthesia. Cortical temperature decreases were not accompanied by a concomitant decrease in the γ-band local field potential power, multiunit firing rate, or locomotion behavior, which all returned to baseline within a few minutes after the cessation of anesthesia. In anesthetized animals where core body temperature was kept constant, cortical temperature was still >1°C lower than in the awake animal. Thermocouples implanted in the subcortex showed similar temperature changes under anesthesia, suggesting these responses occur throughout the brain. Two-photon microscopy of individual blood vessel dynamics following brief isoflurane exposure revealed a large increase in vessel diameter that ceased before the brain temperature significantly decreased, indicating cerebral heat loss was not due to increased cerebral blood vessel dilation. These data should be considered in experimental designs recording in anesthetized preparations, computational models relating temperature and neural activity, and awake-behaving methods that require brief anesthesia before experimental procedures. PMID:25972579

  19. Hierarchical Organization of Human Cortical Networks in Health and Schizophrenia

    PubMed Central

    Bassett, Danielle S.; Bullmore, Edward; Verchinski, Beth A.; Mattay, Venkata S.; Weinberger, Daniel R.; Meyer-Lindenberg, Andreas

    2009-01-01

    The complex organization of connectivity in the human brain is incompletely understood. Recently, topological measures based on graph theory have provided a new approach to quantify large-scale cortical networks. These methods have been applied to anatomical connectivity data on non-human species and cortical networks have been shown to have small-world topology, associated with high local and global efficiency of information transfer. Anatomical networks derived from cortical thickness measurements have shown the same organizational properties of the healthy human brain, consistent with similar results reported in functional networks derived from resting state functional MRI and MEG data. Here we show, using anatomical networks derived from analysis of inter-regional covariation of gray matter volume in magnetic resonance imaging (MRI) data on 259 healthy volunteers, that classical divisions of cortex (multimodal, unimodal and transmodal) have some distinct topological attributes. While all cortical divisions shared non-random properties of small-worldness and efficient wiring (short mean Euclidean distance between connected regions), the multimodal network had a hierarchical organization, dominated by frontal hubs with low clustering, whereas the transmodal network was assortative. Moreover, in a sample of 203 people with schizophrenia, multimodal network organization was abnormal, as indicated by reduced hierarchy, the loss of frontal and the emergence of non-frontal hubs, and increased connection distance. We propose that the topological differences between divisions of normal cortex may represent the outcome of different growth processes for multimodal and transmodal networks; and that neurodevelopmental abnormalities in schizophrenia specifically impact multimodal cortical organization. PMID:18784304

  20. Cortical Network Dynamics of Perceptual Decision-Making in the Human Brain

    PubMed Central

    Siegel, Markus; Engel, Andreas K.; Donner, Tobias H.

    2011-01-01

    Goal-directed behavior requires the flexible transformation of sensory evidence about our environment into motor actions. Studies of perceptual decision-making have shown that this transformation is distributed across several widely separated brain regions. Yet, little is known about how decision-making emerges from the dynamic interactions among these regions. Here, we review a series of studies, in which we characterized the cortical network interactions underlying a perceptual decision process in the human brain. We used magnetoencephalography to measure the large-scale cortical population dynamics underlying each of the sub-processes involved in this decision: the encoding of sensory evidence and action plan, the mapping between the two, and the attentional selection of task-relevant evidence. We found that these sub-processes are mediated by neuronal oscillations within specific frequency ranges. Localized gamma-band oscillations in sensory and motor cortices reflect the encoding of the sensory evidence and motor plan. Large-scale oscillations across widespread cortical networks mediate the integrative processes connecting these local networks: Gamma- and beta-band oscillations across frontal, parietal, and sensory cortices serve the selection of relevant sensory evidence and its flexible mapping onto action plans. In sum, our results suggest that perceptual decisions are mediated by oscillatory interactions within overlapping local and large-scale cortical networks. PMID:21427777

  1. Incidence and predictors of 30-day readmission for patients discharged home after craniotomy for malignant supratentorial tumors in California (1995-2010).

    PubMed

    Marcus, Logan P; McCutcheon, Brandon A; Noorbakhsh, Abraham; Parina, Ralitza P; Gonda, David D; Chen, Clark; Chang, David C; Carter, Bob S

    2014-05-01

    Hospital readmission within 30 days of discharge is a major contributor to the high cost of health care in the US and is also a major indicator of patient care quality. The purpose of this study was to investigate the incidence, causes, and predictors of 30-day readmission following craniotomy for malignant supratentorial tumor resection. The longitudinal California Office of Statewide Health Planning & Development inpatient-discharge administrative database is a data set that consists of 100% of all inpatient hospitalizations within the state of California and allows each patient to be followed throughout multiple inpatient hospital stays, across multiple institutions, and over multiple years (from 1995 to 2010). This database was used to identify patients who underwent a craniotomy for resection of primary malignant brain tumors. Causes for unplanned 30-day readmission were identified by principle ICD-9 diagnosis code and multivariate analysis was used to determine the independent effect of various patient factors on 30-day readmissions. A total of 18,506 patients received a craniotomy for the treatment of primary malignant brain tumors within the state of California between 1995 and 2010. Four hundred ten patients (2.2%) died during the index surgical admission, 13,586 patients (73.4%) were discharged home, and 4510 patients (24.4%) were transferred to another facility. Among patients discharged home, 1790 patients (13.2%) were readmitted at least once within 30 days of discharge, with 27% of readmissions occurring at a different hospital than the initial surgical institution. The most common reasons for readmission were new onset seizure and convulsive disorder (20.9%), surgical infection of the CNS (14.5%), and new onset of a motor deficit (12.8%). Medi-Cal beneficiaries were at increased odds for readmission relative to privately insured patients (OR 1.52, 95% CI 1.20-1.93). Patients with a history of prior myocardial infarction were at an increased risk of

  2. [Sepsis associated encephalopathy is an independently risk factor for nosocomial coma in patients with supratentorial intracerebral hemorrhage: a retrospective cohort study of 261 patients].

    PubMed

    Wang, Guangsheng; Wang, Shaodan; Zhou, Yeting; Chen, Xiaodong; Ma, Xiaobo; Tong, Daoming

    2016-08-01

    To investigate whether the presence of sepsis associated encephalopathy (SAE) would predict nosocomial coma (NC) and poor outcome in patients with supratentorial intracerebral hemorrhage (SICH). A retrospective cohort study was conducted. The adult acute SICH patients with or without coma admitted to intensive care unit (ICU) of Shuyang People' Hospital Affiliated to Xuzhou Medical University from December 2012 to December 2015 were enrolled. Brain computed tomography (CT) scans were analyzed and the patients were divided into pre-hospital coma (PC) and NC groups. The clinical data and the incidence of SAE of patients in two groups were compared, and the 30-day prognosis was followed up. Univariate and Cox regression analyses were performed to analyze whether SAE would predict NC and poor outcome in patients with SICH. A total of 330 patients with acute SICH and coma were enrolled, excluding 60 cases of infratentorial cerebral hemorrhage, 3 cases of primary intraventricular hemorrhage, and 6 cases of unknown volume hematoma. Finally, 261 patients were included, with 111 patients of NC events, and 150 patients of PC events. 69 (62.2%) SAE in SICH with NC and 33 (22.2%) SAE in SICH with PC was diagnosed, and the incidence of SAE between two groups was statistically significant (P < 0.01). Compared with PC group, SICH patients in the NC group had lower incidence of hypertension (81.1% vs. 96.0%), longer time from onset to NC [days: 2.3 (23.9) vs. 0 (0.5)] and length of ICU stay [days: 5.0 (34.0) vs. 3.0 (12.0)], higher initial Glasgow coma score (GCS, 10.2±1.5 vs. 6.6±1.6) and sequential organ failure assessment (SOFA) score [4.0 (6.0) vs. 3.0 (3.0)], lower initial National Institutes of Health Stroke Scale (NIHSS) score (19.4±6.6 vs. 30.2±6.8), as well as more frequent sepsis (78.4% vs. 38.0%), vegetative state (24.3% vs. 14.0%), acute respiratory failure (24.3% vs. 10.0%), pneumonia (37.8% vs. 24.0%), septic shock (8.1% vs. 0), acute liver failure (5.4% vs. 0

  3. Pathogenetic mechanisms of focal cortical dysplasia.

    PubMed

    Marin-Valencia, Isaac; Guerrini, Renzo; Gleeson, Joseph G

    2014-07-01

    Focal cortical dysplasias (FCDs) constitute a prevalent cause of intractable epilepsy in children, and is one of the leading conditions requiring epilepsy surgery. Despite recent advances in the cellular and molecular biology of these conditions, the pathogenetic mechanisms of FCDs remain largely unknown. The purpose if this work is to review the molecular underpinnings of FCDs and to highlight potential therapeutic targets. A systematic review of the literature regarding the histologic, molecular, and electrophysiologic aspects of FCDs was conducted. Disruption of the mammalian target of rapamycin (mTOR) signaling comprises a common pathway underlying the structural and electrical disturbances of some FCDs. Other mechanisms such as viral infections, prematurity, head trauma, and brain tumors are also posited. mTOR inhibitors (i.e., rapamycin) have shown positive results on seizure management in animal models and in a small cohort of patients with FCD. Encouraging progress has been achieved on the molecular and electrophysiologic basis of constitutive cells in the dysplastic tissue. Despite the promising results of mTOR inhibitors, large-scale randomized trials are in need to evaluate their efficacy and side effects, along with additional mechanistic studies for the development of novel, molecular-based diagnostic and therapeutic approaches. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  4. Cortical thickness gradients in structural hierarchies

    PubMed Central

    Wagstyl, Konrad; Ronan, Lisa; Goodyer, Ian M.; Fletcher, Paul C.

    2015-01-01

    MRI, enabling in vivo analysis of cortical morphology, offers a powerful tool in the assessment of brain development and pathology. One of the most ubiquitous measures used—the thickness of the cortex—shows abnormalities in a number of diseases and conditions, but the functional and biological correlates of such alterations are unclear. If the functional connotations of structural MRI measures are to be understood, we must strive to clarify the relationship between measures such as cortical thickness and their cytoarchitectural determinants. We therefore sought to determine whether patterns of cortical thickness mirror a key motif of the cortex, specifically its structural hierarchical organisation. We delineated three sensory hierarchies (visual, somatosensory and auditory) in two species—macaque and human—and explored whether cortical thickness was correlated with specific cytoarchitectural characteristics. Importantly, we controlled for cortical folding which impacts upon thickness and may obscure regional differences. Our results suggest that an easily measurable macroscopic brain parameter, namely, cortical thickness, is systematically related to cytoarchitecture and to the structural hierarchical organisation of the cortex. We argue that the measurement of cortical thickness gradients may become an important way to develop our understanding of brain structure–function relationships. The identification of alterations in such gradients may complement the observation of regionally localised cortical thickness changes in our understanding of normal development and neuropsychiatric illnesses. PMID:25725468

  5. Cortical silent period reveals differences between adductor spasmodic dysphonia and muscle tension dysphonia

    PubMed Central

    Samargia, Sharyl; Schmidt, Rebekah; Kimberley, Teresa Jacobson

    2015-01-01

    Background The pathophysiology of adductor spasmodic dysphonia (AdSD), like other focal dystonias, is largely unknown. Objective The purposes of this study were to determine 1) cortical excitability differences between AdSD, muscle tension dysphonia (MTD) and healthy controls 2) distribution of potential differences in cranial or skeletal muscle, and 3) if cortical excitability measures assist in the differential diagnosis of AdSD and MTD. Methods 10 participants with adductor spasmodic dysphonia, 8 with muscle tension dysphonia and 10 healthy controls received single and paired pulse transcranial magnetic stimulation (TMS) to the primary motor cortex contralateral to tested muscles, first dorsal interosseus (FDI) and masseter. We tested the hypothesis that cortical excitability measures in AdSD would be significantly different than in MTD and healthy. In addition, we hypothesized there would be a correlation between cortical excitability measures and clinical voice severity in AdSD. Results Cortical silent period (CSP) duration in masseter and FDI was significantly shorter in AdSD than MTD and healthy controls. Other measures failed to demonstrate differences. Conclusion There are differences in cortical excitability between AdSD, MTD and healthy controls. These differences in the cortical measure of both the FDI and masseter muscles in AdSD suggest widespread dysfunction of the GABAB mechanism may be a pathophysiologic feature of AdSD, similar to other forms of focal dystonia. Further exploration of the use of TMS to assist in the differential diagnosis of AdSD and MTD is warranted. PMID:26089309

  6. An essential role of SVZ progenitors in cortical folding in gyrencephalic mammals

    PubMed Central

    Toda, Tomohisa; Shinmyo, Yohei; Dinh Duong, Tung Anh; Masuda, Kosuke; Kawasaki, Hiroshi

    2016-01-01

    Because folding of the cerebral cortex in the mammalian brain is believed to be crucial for higher brain functions, the mechanisms underlying its formation during development and evolution are of great interest. Although it has been proposed that increased neural progenitors in the subventricular zone (SVZ) are responsible for making cortical folds, their roles in cortical folding are still largely unclear, mainly because genetic methods for gyrencephalic mammals had been poorly available. Here, by taking an advantage of our newly developed in utero electroporation technique for the gyrencephalic brain of ferrets, we investigated the role of SVZ progenitors in cortical folding. We found regional differences in the abundance of SVZ progenitors in the developing ferret brain even before cortical folds began to be formed. When Tbr2 transcription factor was inhibited, intermediate progenitor cells were markedly reduced in the ferret cerebral cortex. Interestingly, outer radial glial cells were also reduced by inhibiting Tbr2. We uncovered that reduced numbers of SVZ progenitors resulted in impaired cortical folding. When Tbr2 was inhibited, upper cortical layers were preferentially reduced in gyri compared to those in sulci. Our findings indicate the biological importance of SVZ progenitors in cortical folding in the gyrencephalic brain. PMID:27403992

  7. Cortical cartography and Caret software.

    PubMed

    Van Essen, David C

    2012-08-15

    Caret software is widely used for analyzing and visualizing many types of fMRI data, often in conjunction with experimental data from other modalities. This article places Caret's development in a historical context that spans three decades of brain mapping--from the early days of manually generated flat maps to the nascent field of human connectomics. It also highlights some of Caret's distinctive capabilities. This includes the ease of visualizing data on surfaces and/or volumes and on atlases as well as individual subjects. Caret can display many types of experimental data using various combinations of overlays (e.g., fMRI activation maps, cortical parcellations, areal boundaries), and it has other features that facilitate the analysis and visualization of complex neuroimaging datasets. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Gyrification from constrained cortical expansion

    NASA Astrophysics Data System (ADS)

    Tallinen, Tuomas

    The convolutions of the human brain are a symbol of its functional complexity. But how does the outer surface of the brain, the layered cortex of neuronal gray matter get its folds? In this talk, we ask to which extent folding of the brain can be explained as a purely mechanical consequence of unpatterned growth of the cortical layer relative to the sublayers. Modeling the growing brain as a soft layered solid leads to elastic instabilities and the formation of cusped sulci and smooth gyri consistent with observations across species in both normal and pathological situations. Furthermore, we apply initial geometries obtained from fetal brain MRI to address the question of how the brain geometry and folding patterns may be coupled via mechanics.

  9. Cortical Cartography and Caret Software

    PubMed Central

    Van Essen, David C.

    2011-01-01

    Caret software is widely used for analyzing and visualizing many types of fMRI data, often in conjunction with experimental data from other modalities. This article places Caret’s development in a historical context that spans three decades of brain mapping – from the early days of manually generated flat maps to the nascent field of human connectomics. It also highlights some of Caret’s distinctive capabilities. This includes the ease of visualizing data on surfaces and/or volumes and on atlases as well as individual subjects. Caret can display many types of experimental data using various combinations of overlays (e.g., fMRI activation maps, cortical parcellations, areal boundaries), and it has other features that facilitate the analysis and visualization of complex neuroimaging datasets. PMID:22062192

  10. From genes to folds: a review of cortical gyrification theory.

    PubMed

    Ronan, Lisa; Fletcher, Paul C

    2015-09-01

    Cortical gyrification is not a random process. Instead, the folds that develop are synonymous with the functional organization of the cortex, and form patterns that are remarkably consistent across individuals and even some species. How this happens is not well understood. Although many developmental features and evolutionary adaptations have been proposed as the primary cause of gyrencephaly, it is not evident that gyrification is reducible in this way. In recent years, we have greatly increased our understanding of the multiple factors that influence cortical folding, from the action of genes in health and disease to evolutionary adaptations that characterize distinctions between gyrencephalic and lissencephalic cortices. Nonetheless it is unclear how these factors which influence events at a small-scale synthesize to form the consistent and biologically meaningful large-scale features of sulci and gyri. In this article, we review the empirical evidence which suggests that gyrification is the product of a generalized mechanism, namely the differential expansion of the cortex. By considering the implications of this model, we demonstrate that it is possible to link the fundamental biological components of the cortex to its large-scale pattern-specific morphology and functional organization.

  11. Mapping human brain networks with cortico-cortical evoked potentials.

    PubMed

    Keller, Corey J; Honey, Christopher J; Mégevand, Pierre; Entz, Laszlo; Ulbert, Istvan; Mehta, Ashesh D

    2014-10-05

    The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex.

  12. Dense Neuron Clustering Explains Connectivity Statistics in Cortical Microcircuits

    PubMed Central

    Klinshov, Vladimir V.; Teramae, Jun-nosuke; Nekorkin, Vladimir I.; Fukai, Tomoki

    2014-01-01

    Local cortical circuits appear highly non-random, but the underlying connectivity rule remains elusive. Here, we analyze experimental data observed in layer 5 of rat neocortex and suggest a model for connectivity from which emerge essential observed non-random features of both wiring and weighting. These features include lognormal distributions of synaptic connection strength, anatomical clustering, and strong correlations between clustering and connection strength. Our model predicts that cortical microcircuits contain large groups of densely connected neurons which we call clusters. We show that such a cluster contains about one fifth of all excitatory neurons of a circuit which are very densely connected with stronger than average synapses. We demonstrate that such clustering plays an important role in the network dynamics, namely, it creates bistable neural spiking in small cortical circuits. Furthermore, introducing local clustering in large-scale networks leads to the emergence of various patterns of persistent local activity in an ongoing network activity. Thus, our results may bridge a gap between anatomical structure and persistent activity observed during working memory and other cognitive processes. PMID:24732632

  13. Mapping human brain networks with cortico-cortical evoked potentials

    PubMed Central

    Keller, Corey J.; Honey, Christopher J.; Mégevand, Pierre; Entz, Laszlo; Ulbert, Istvan; Mehta, Ashesh D.

    2014-01-01

    The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex. PMID:25180306

  14. Unsupervised fetal cortical surface parcellation

    PubMed Central

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-01-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features. PMID:27413248

  15. Unsupervised fetal cortical surface parcellation

    NASA Astrophysics Data System (ADS)

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-03-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features.

  16. Presymptomatic cortical thinning in familial Alzheimer disease

    PubMed Central

    Nicholas, Jennifer M.; Lehmann, Manja; Ryan, Natalie S.; Liang, Yuying; Macpherson, Kirsty; Modat, Marc; Rossor, Martin N.; Schott, Jonathan M.; Ourselin, Sebastien; Fox, Nick C.

    2016-01-01

    Objective: To identify a cortical signature pattern of cortical thinning in familial Alzheimer disease (FAD) and assess its utility in detecting and tracking presymptomatic neurodegeneration. Methods: We recruited 43 FAD mutation carriers—36 PSEN1, 7 APP (20 symptomatic, 23 presymptomatic)—and 42 healthy controls to a longitudinal clinical and MRI study. T1-weighted MRI scans were acquired at baseline in all participants; 55 individuals (33 mutation carriers; 22 controls) had multiple (mean 2.9) follow-up scans approximately annually. Cortical thickness was measured using FreeSurfer. A cortical thinning signature was identified from symptomatic FAD participants. We then examined cortical thickness changes in this signature region in presymptomatic carriers and assessed associations with cognitive performance. Results: The cortical signature included 6 regions: entorhinal cortex, inferior parietal cortex, precuneus, superior parietal cortex, superior frontal cortex, and supramarginal gyrus. There were significant differences in mean cortical signature thickness between mutation carriers and controls 3 years before predicted symptom onset. The earliest significant difference in a single region, detectable 4 years preonset, was in the precuneus. Rate of change in cortical thickness became significantly different in the cortical signature at 5 years before predicted onset, and in the precuneus at 8 years preonset. Baseline mean signature thickness predicted rate of subsequent thinning and correlated with presymptomatic cognitive change. Conclusions: The FAD cortical signature appears to be similar to that described for sporadic AD. All component regions showed significant presymptomatic thinning. A composite signature may provide more robust results than a single region and have utility as an outcome measure in presymptomatic trials. PMID:27733562

  17. Stereotypic wheel running decreases cortical activity in mice

    PubMed Central

    Fisher, Simon P.; Cui, Nanyi; McKillop, Laura E.; Gemignani, Jessica; Bannerman, David M.; Oliver, Peter L.; Peirson, Stuart N.; Vyazovskiy, Vladyslav V.

    2016-01-01

    Prolonged wakefulness is thought to gradually increase ‘sleep need' and influence subsequent sleep duration and intensity, but the role of specific waking behaviours remains unclear. Here we report the effect of voluntary wheel running during wakefulness on neuronal activity in the motor and somatosensory cortex in mice. We find that stereotypic wheel running is associated with a substantial reduction in firing rates among a large subpopulation of cortical neurons, especially at high speeds. Wheel running also has longer-term effects on spiking activity across periods of wakefulness. Specifically, cortical firing rates are significantly higher towards the end of a spontaneous prolonged waking period. However, this increase is abolished when wakefulness is dominated by running wheel activity. These findings indicate that wake-related changes in firing rates are determined not only by wake duration, but also by specific waking behaviours. PMID:27748455

  18. A cortical circuit for gain control by behavioral state.

    PubMed

    Fu, Yu; Tucciarone, Jason M; Espinosa, J Sebastian; Sheng, Nengyin; Darcy, Daniel P; Nicoll, Roger A; Huang, Z Josh; Stryker, Michael P

    2014-03-13

    The brain's response to sensory input is strikingly modulated by behavioral state. Notably, the visual response of mouse primary visual cortex (V1) is enhanced by locomotion, a tractable and accessible example of a time-locked change in cortical state. The neural circuits that transmit behavioral state to sensory cortex to produce this modulation are unknown. In vivo calcium imaging of behaving animals revealed that locomotion activates vasoactive intestinal peptide (VIP)-positive neurons in mouse V1 independent of visual stimulation and largely through nicotinic inputs from basal forebrain. Optogenetic activation of VIP neurons increased V1 visual responses in stationary awake mice, artificially mimicking the effect of locomotion, and photolytic damage of VIP neurons abolished the enhancement of V1 responses by locomotion. These findings establish a cortical circuit for the enhancement of visual response by locomotion and provide a potential common circuit for the modulation of sensory processing by behavioral state.

  19. Learning-Based Topological Correction for Infant Cortical Surfaces

    PubMed Central

    Hao, Shijie; Li, Gang; Wang, Li; Meng, Yu

    2017-01-01

    Reconstruction of topologically correct and accurate cortical surfaces from infant MR images is of great importance in neuroimaging mapping of early brain development. However, due to rapid growth and ongoing myelination, infant MR images exhibit extremely low tissue contrast and dynamic appearance patterns, thus leading to much more topological errors (holes and handles) in the cortical surfaces derived from tissue segmentation results, in comparison to adult MR images which typically have good tissue contrast. Existing methods for topological correction either rely on the minimal correction criteria, or ad hoc rules based on image intensity priori, thus often resulting in erroneous correction and large anatomical errors in reconstructed infant cortical surfaces. To address these issues, we propose to correct topological errors by learning information from the anatomical references, i.e., manually corrected images. Specifically, in our method, we first locate candidate voxels of topologically defected regions by using a topology-preserving level set method. Then, by leveraging rich information of the corresponding patches from reference images, we build region-specific dictionaries from the anatomical references and infer the correct labels of candidate voxels using sparse representation. Notably, we further integrate these two steps into an iterative framework to enable gradual correction of large topological errors, which are frequently occurred in infant images and cannot be completely corrected using one-shot sparse representation. Extensive experiments on infant cortical surfaces demonstrate that our method not only effectively corrects the topological defects, but also leads to better anatomical consistency, compared to the state-of-the-art methods.

  20. Decreased Regional Cortical Thickness and Thinning Rate Are Associated with Inattention Symptoms in Healthy Children

    PubMed Central

    Ducharme, Simon; Hudziak, James J.; Botteron, Kelly N.; Albaugh, Matthew D.; Nguyen, Tuong-Vi; Karama, Sherif; Evans, Alan C.

    2011-01-01

    Objective Children with attention-deficit/hyperactivity disorder (ADHD) have delayed cortical maturation, evidenced by regionally specific slower cortical thinning. However, the relationship between cortical maturation and attention capacities in typically developing children is unknown. This study examines cortical thickness correlates of inattention symptoms in a large sample of healthy children. Method Data from 357 healthy subjects (6.0–18.4 years of age) were obtained from the NIH MRI Study of Normal Brain Development. In cross-sectional analysis (first visit, n = 257), Child Behavior Checklist Attention Problems (AP) scores were linearly regressed against cortical thickness, controlling for age, gender, total brain volume, and site. For longitudinal data (up to three visits, n = 357/672 scans), similar analyses were performed using mixed-effects linear regressions. Interactions of AP with age and gender were tested. Results A cross-sectional “AP by age” interaction was found in bilateral orbito-frontal cortex, right inferior frontal cortex, bilateral ventromedial prefrontal cortex, bilateral dorsolateral prefrontal cortex, and several additional attention network regions. The interaction was due to negative associations between AP and thickness in younger subjects (6–10 years of age) that gradually disappeared over time secondary to slower cortical thinning. Similar trends were present in longitudinal analyses. Conclusions Higher AP scores were associated with thinner cortex at baseline and slower cortical thinning with aging in multiple areas involved in attention processes. Similar patterns have been identified in ADHD, suggesting a dimensional component to the link between attention and cortical maturation. The identified association between cortical maturation and attention in healthy development will help to inform studies of neuroimaging biomarkers of ADHD. PMID:22176936

  1. Sensory experience regulates cortical inhibition by inducing IGF1 in VIP neurons.

    PubMed

    Mardinly, A R; Spiegel, I; Patrizi, A; Centofante, E; Bazinet, J E; Tzeng, C P; Mandel-Brehm, C; Harmin, D A; Adesnik, H; Fagiolini, M; Greenberg, M E

    2016-03-17

    Inhibitory neurons regulate the adaptation of neural circuits to sensory experience, but the molecular mechanisms by which experience controls the connectivity between different types of inhibitory neuron to regulate cortical plasticity are largely unknown. Here we show that exposure of dark-housed mice to light induces a gene program in cortical vasoactive intestinal peptide (VIP)-expressing neurons that is markedly distinct from that induced in excitatory neurons and other subtypes of inhibitory neuron. We identify Igf1 as one of several activity-regulated genes that are specific to VIP neurons, and demonstrate that IGF1 functions cell-autonomously in VIP neurons to increase inhibitory synaptic input onto these neurons. Our findings further suggest that in cortical VIP neurons, experience-dependent gene transcription regulates visual acuity by activating the expression of IGF1, thus promoting the inhibition of disinhibitory neurons and affecting inhibition onto cortical pyramidal neurons.

  2. Cortical Feedback Control of Olfactory Bulb Circuits

    PubMed Central

    Boyd, Alison M.; Sturgill, James F.; Poo, Cindy; Isaacson, Jeffry S.

    2013-01-01

    SUMMARY Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition. PMID:23259951

  3. Cortical Alterations in Medication-Overuse Headache.

    PubMed

    Riederer, Franz; Schaer, Marie; Gantenbein, Andreas R; Luechinger, Roger; Michels, Lars; Kaya, Marihan; Kollias, Spyridon; Sándor, Peter S

    2017-02-01

    Using surface-based morphometry we aimed to provide a detailed examination of cortical alterations in medication-overuse headache (MOH), by disentangling between altered cortical thickness and gyrification (folding). In MOH, pain modulation is probably dysfunctional at the cortical and subcortical level, resulting in a disequilibrium between pain inhibition and facilitation. Both increased and decreased cortical volumes have been reported in individuals with MOH. There is however no detailed examination to date that distinguishes between altered cortical thickness and gyrification. Such distinction would help to identify the nature and timing of neurodevelopmental mechanisms at play in affected individuals. We investigated cortical thickness and gyrification in 29 patients with MOH according to International Headache Society criteria and 29 age- and gender-matched controls, using high-resolution structural MRIs of the brain analyzed with FreeSurfer. This is a secondary analysis of data from a previously published voxel-based morphometry study. In patients with MOH compared to controls, reduced cortical thickness was observed in the left prefrontal cortex. We also observed higher local gyrification in one cluster extending from the fusiform cortex to adjacent medial temporal regions, and in another cluster in the right occipital pole. Higher gyrification in the right occipital pole predicted poor response after detoxification. Corroborating previous volumetric results, our study adds information on the putative neurobiological mechanisms involved in MOH, suggesting neurodevelopmental changes in MOH. © 2016 American Headache Society.

  4. A Turing Reaction-Diffusion Model for Human Cortical Folding Patterns and Cortical Pattern Malformations

    NASA Astrophysics Data System (ADS)

    Hurdal, Monica K.; Striegel, Deborah A.

    2011-11-01

    Modeling and understanding cortical folding pattern formation is important for quantifying cortical development. We present a biomathematical model for cortical folding pattern formation in the human brain and apply this model to study diseases involving cortical pattern malformations associated with neural migration disorders. Polymicrogyria is a cortical malformation disease resulting in an excessive number of small gyri. Our mathematical model uses a Turing reaction-diffusion system to model cortical folding. The lateral ventricle (LV) and ventricular zone (VZ) of the brain are critical components in the formation of cortical patterning. In early cortical development the shape of the LV can be modeled with a prolate spheroid and the VZ with a prolate spheroid surface. We use our model to study how global cortex characteristics, such as size and shape of the LV, affect cortical pattern formation. We demonstrate increasing domain scale can increase the number of gyri and sulci formed. Changes in LV shape can account for sulcus directionality. By incorporating LV size and shape, our model is able to elucidate which parameters can lead to excessive cortical folding.

  5. T1 correlates age: A short-TE MR relaxometry study in vivo on human cortical bone free water at 1.5T.

    PubMed

    Akbari, Atena; Abbasi-Rad, Shahrokh; Rad, Hamidreza Saligheh

    2016-02-01

    Large pores of human cortical bone (>30μm) are filled with fluids, essentially consisting of water, suggesting that cortical bone free water can be considered as a reliable surrogate measure of cortical bone porosity and hence quality. Signal from such pores can be reliably captured using Short Echo Time (STE) pulse sequence with echo-time in the range of 1-1.5msec (which should be judiciously selected correspond to T2(⁎) value of free water molecules). Furthermore, it is well-known that cortical bone T1-relaxivity is a function of its geometry, suggesting that cortical bone free water increases with age. In this work, we quantified cortical bone free water longitudinal relaxation time (T1) by a Dual-TR technique using STE pulse sequence. In the sequel, we investigated relationship between STE-derived cortical bone free water T1-values and age in a group of healthy volunteers (thirty subjects covering the age range of 20-70years) at 1.5T. Preliminary results showed that cortical bone free water T1 highly correlates with age (r(2)=0.73, p<0.0001), representing cortical bone free water T1 as a reliable indicator of cortical bone porosity and age-related deterioration. It can be concluded that STE-MRI can be utilized as proper alternative in quantifying cortical bone porosity parameters in-vivo, with the advantages of widespread clinical availability and being cost-effective.

  6. Emergence of Metastable State Dynamics in Interconnected Cortical Networks with Propagation Delays

    PubMed Central

    Kutchko, Katrina M.; Fröhlich, Flavio

    2013-01-01

    The importance of the large number of thin-diameter and unmyelinated axons that connect different cortical areas is unknown. The pronounced propagation delays in these axons may prevent synchronization of cortical networks and therefore hinder efficient information integration and processing. Yet, such global information integration across cortical areas is vital for higher cognitive function. We hypothesized that delays in communication between cortical areas can disrupt synchronization and therefore enhance the set of activity trajectories and computations interconnected networks can perform. To evaluate this hypothesis, we studied the effect of long-range cortical projections with propagation delays in interconnected large-scale cortical networks that exhibited spontaneous rhythmic activity. Long-range connections with delays caused the emergence of metastable, spatio-temporally distinct activity states between which the networks spontaneously transitioned. Interestingly, the observed activity patterns correspond to macroscopic network dynamics such as globally synchronized activity, propagating wave fronts, and spiral waves that have been previously observed in neurophysiological recordings from humans and animal models. Transient perturbations with simulated transcranial alternating current stimulation (tACS) confirmed the multistability of the interconnected networks by switching the networks between these metastable states. Our model thus proposes that slower long-range connections enrich the landscape of activity states and represent a parsimonious mechanism for the emergence of multistability in cortical networks. These results further provide a mechanistic link between the known deficits in connectivity and cortical state dynamics in neuropsychiatric illnesses such as schizophrenia and autism, as well as suggest non-invasive brain stimulation as an effective treatment for these illnesses. PMID:24204238

  7. Inferring pathological states in cortical neuron microcircuits.

    PubMed

    Rydzewski, Jakub; Nowak, Wieslaw; Nicosia, Giuseppe

    2015-12-07

    The brain activity is to a large extent determined by states of neural cortex microcircuits. Unfortunately, accuracy of results from neural circuits׳ mathematical models is often biased by the presence of uncertainties in underlying experimental data. Moreover, due to problems with uncertainties identification in a multidimensional parameters space, it is almost impossible to classify states of the neural cortex, which correspond to a particular set of the parameters. Here, we develop a complete methodology for determining uncertainties and the novel protocol for classifying all states in any neuroinformatic model. Further, we test this protocol on the mathematical, nonlinear model of such a microcircuit developed by Giugliano et al. (2008) and applied in the experimental data analysis of Huntington׳s disease. Up to now, the link between parameter domains in the mathematical model of Huntington׳s disease and the pathological states in cortical microcircuits has remained unclear. In this paper we precisely identify all the uncertainties, the most crucial input parameters and domains that drive the system into an unhealthy state. The scheme proposed here is general and can be easily applied to other mathematical models of biological phenomena. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Cortical Integration of Audio-Visual Information

    PubMed Central

    Vander Wyk, Brent C.; Ramsay, Gordon J.; Hudac, Caitlin M.; Jones, Warren; Lin, David; Klin, Ami; Lee, Su Mei; Pelphrey, Kevin A.

    2013-01-01

    We investigated the neural basis of audio-visual processing in speech and non-speech stimuli. Physically identical auditory stimuli (speech and sinusoidal tones) and visual stimuli (animated circles and ellipses) were used in this fMRI experiment. Relative to unimodal stimuli, each of the multimodal conjunctions showed increased activation in largely non-overlapping areas. The conjunction of Ellipse and Speech, which most resembles naturalistic audiovisual speech, showed higher activation in the right inferior frontal gyrus, fusiform gyri, left posterior superior temporal sulcus, and lateral occipital cortex. The conjunction of Circle and Tone, an arbitrary audio-visual pairing with no speech association, activated middle temporal gyri and lateral occipital cortex. The conjunction of Circle and Speech showed activation in lateral occipital cortex, and the conjunction of Ellipse and Tone did not show increased activation relative to unimodal stimuli. Further analysis revealed that middle temporal regions, although identified as multimodal only in the Circle-Tone condition, were more strongly active to Ellipse-Speech or Circle-Speech, but regions that were identified as multimodal for Ellipse-Speech were always strongest for Ellipse-Speech. Our results suggest that combinations of auditory and visual stimuli may together be processed by different cortical networks, depending on the extent to which speech or non-speech percepts are evoked. PMID:20709442

  9. Movement, confusion, and orienting in frontal cortices.

    PubMed

    Brecht, Michael

    2011-10-20

    In this issue, two studies, by Ehrlich et al. and Hill et al., address the role of the frontal motor cortices in behavior of the rat and suggest a potential role for this structure in high-level control of diverse behaviors. Hill et al. show that motor cortical neurons predict whisker movements even without sensory feedback and that their activity reflects efferent control. Surprisingly, Ehrlich et al. report the participation of this same cortical region in the preparation and execution of orienting behaviors.

  10. Osmosis in Cortical Collecting Tubules

    PubMed Central

    Schafer, James A.; Patlak, Clifford S.; Andreoli, Thomas E.

    1974-01-01

    This paper reports a theoretical analysis of osmotic transients and an experimental evaluation both of rapid time resolution of lumen to bath osmosis and of bidirectional steady-state osmosis in isolated rabbit cortical collecting tubules exposed to antidiuretic hormone (ADH). For the case of a membrane in series with unstirred layers, there may be considerable differences between initial and steady-state osmotic flows (i.e., the osmotic transient phenomenon), because the solute concentrations at the interfaces between membrane and unstirred layers may vary with time. A numerical solution of the equation of continuity provided a means for computing these time-dependent values, and, accordingly, the variation of osmotic flow with time for a given set of parameters including: Pf (cm s–1), the osmotic water permeability coefficient, the bulk phase solute concentrations, the unstirred layer thickness on either side of the membrane, and the fractional areas available for volume flow in the unstirred layers. The analyses provide a quantitative frame of reference for evaluating osmotic transients observed in epithelia in series with asymmetrical unstirred layers and indicate that, for such epithelia, Pf determinations from steady-state osmotic flows may result in gross underestimates of osmotic water permeability. In earlier studies, we suggested that the discrepancy between the ADH-dependent values of Pf and PDDw (cm s–1, diffusional water permeability coefficient) was the consequence of cellular constraints to diffusion. In the present experiments, no transients were detectable 20–30 s after initiating ADH-dependent lumen to bath osmosis; and steady-state ADH-dependent osmotic flows from bath to lumen and lumen to bath were linear and symmetrical. An evaluation of these data in terms of the analytical model indicates: First, cellular constraints to diffusion in cortical collecting tubules could be rationalized in terms of a 25-fold reduction in the area of the

  11. Measurement of cortical thickness asymmetry in carotid occlusive disease.

    PubMed

    Asllani, Iris; Slattery, Pamelia; Fafard, Alexander; Pavol, Marykay; Lazar, Ronald M; Marshall, Randolph S

    2016-01-01

    Despite being considered an important anatomical parameter directly related to neuronal density, cortical thickness is not routinely assessed in studies of the human brain in vivo. This paucity has been largely due to the size and convoluted shape of the human cortex, which has made it difficult to develop automated algorithms that can measure cortical thickness efficiently and reliably. Since the development of such an algorithm by Fischl and Dale in 2000, the number of studies investigating the relationship between cortical thickness and other physiological parameters in the brain has been on the rise. There have been no studies however that have validated cortical asymmetry against known vascular anatomy. To this aim, using high-resolution MRI, we measured cortical thickness and volume in the primary motor (M1) and primary visual (V1) cortex in patients with unilateral, high-grade carotid occlusive disease (n = 29, age = 74 ± 10 years). These regions were selected based on the hypothesis that there will be thinning of the cortical thickness of M1 in the territory supplied by the occluded carotid artery, whereas V1 will show no asymmetry since its blood supply is provided by unaffected posterior arteries. To test for an effect of handedness, cortical thickness and volume were also measured in healthy volunteers (n = 8, age = 37 ± 13 years). In patients, we found thinner cortex in M1 on the occluded side (mean = 2.07 ± 0.19 mm vs 2.15 ± 0.20 mm, p = 0.0008) but no hemispheric difference in V1 (1.80 ± 0.17 mm in occluded vs 1.78 ± 0.16 mm in unoccluded, p = 0.31). Although the mean cortical volume of M1 in the occluded hemisphere was also lower, the difference did not reach statistical significance (p = 0.09). Similarly, in healthy controls, the results showed no hemispheric asymmetry in either cortical thickness or volume in either region (p > 0.1). To test for an orientation bias in the method, the analysis was repeated

  12. Local cortical dynamics of burst suppression in the anaesthetized brain.

    PubMed

    Lewis, Laura D; Ching, Shinung; Weiner, Veronica S; Peterfreund, Robert A; Eskandar, Emad N; Cash, Sydney S; Brown, Emery N; Purdon, Patrick L

    2013-09-01

    Burst suppression is an electroencephalogram pattern that consists of a quasi-periodic alternation between isoelectric 'suppressions' lasting seconds or minutes, and high-voltage 'bursts'. It is characteristic of a profoundly inactivated brain, occurring in conditions including hypothermia, deep general anaesthesia, infant encephalopathy and coma. It is also used in neurology as an electrophysiological endpoint in pharmacologically induced coma for brain protection after traumatic injury and during status epilepticus. Classically, burst suppression has been regarded as a 'global' state with synchronous activity throughout cortex. This assumption has influenced the clinical use of burst suppression as a way to broadly reduce neural activity. However, the extent of spatial homogeneity has not been fully explored due to the challenges in recording from multiple cortical sites simultaneously. The neurophysiological dynamics of large-scale cortical circuits during burst suppression are therefore not well understood. To address this question, we recorded intracranial electrocorticograms from patients who entered burst suppression while receiving propofol general anaesthesia. The electrodes were broadly distributed across cortex, enabling us to examine both the dynamics of burst suppression within local cortical regions and larger-scale network interactions. We found that in contrast to previous characterizations, bursts could be substantially asynchronous across the cortex. Furthermore, the state of burst suppression itself could occur in a limited cortical region while other areas exhibited ongoing continuous activity. In addition, we found a complex temporal structure within bursts, which recapitulated the spectral dynamics of the state preceding burst suppression, and evolved throughout the course of a single burst. Our observations imply that local cortical dynamics are not homogeneous, even during significant brain inactivation. Instead, cortical and, implicitly

  13. Longitudinal changes of cortical microstructure in Parkinson's disease assessed with T1 relaxometry.

    PubMed

    Nürnberger, Lucas; Gracien, René-Maxime; Hok, Pavel; Hof, Stephanie-Michelle; Rüb, Udo; Steinmetz, Helmuth; Hilker, Rüdiger; Klein, Johannes C; Deichmann, Ralf; Baudrexel, Simon

    2017-01-01

    Histological evidence suggests that pathology in Parkinson's disease (PD) goes beyond nigrostriatal degeneration and also affects the cerebral cortex. Quantitative MRI (qMRI) techniques allow the assessment of changes in brain tissue composition. However, the development and pattern of disease-related cortical changes have not yet been demonstrated in PD with qMRI methods. The aim of this study was to investigate longitudinal cortical microstructural changes in PD with quantitative T1 relaxometry. 13 patients with mild to moderate PD and 20 matched healthy subjects underwent high resolution T1 mapping at two time points with an interval of 6.4 years (healthy subjects: 6.5 years). Data from two healthy subjects had to be excluded due to MRI artifacts. Surface-based analysis of cortical T1 values was performed with the FreeSurfer toolbox. In PD patients, a widespread decrease of cortical T1 was detected during follow-up which affected large parts of the temporo-parietal and occipital cortices and also frontal areas. In contrast, age-related T1 decrease in the healthy control group was much less pronounced and only found in lateral frontal, parietal and temporal areas. Average cortical T1 values did not differ between the groups at baseline (p = 0.17), but were reduced in patients at follow-up (p = 0.0004). Annualized relative changes of cortical T1 were higher in patients vs. healthy subjects (patients: - 0.72 ± 0.64%/year; healthy subjects: - 0.17 ± 0.41%/year, p = 0.007). In patients with PD, the development of widespread changes in cortical microstructure was observed as reflected by a reduction of cortical T1. The pattern of T1 decrease in PD patients exceeded the normal T1 decrease as found in physiological aging and showed considerable overlap with the pattern of cortical thinning demonstrated in previous PD studies. Therefore, cortical T1 might be a promising additional imaging marker for future longitudinal PD studies. The biological

  14. Subthalamic stimulation modulates cortical motor network activity and synchronization in Parkinson's disease.

    PubMed

    Weiss, Daniel; Klotz, Rosa; Govindan, Rathinaswamy B; Scholten, Marlieke; Naros, Georgios; Ramos-Murguialday, Ander; Bunjes, Friedemann; Meisner, Christoph; Plewnia, Christian; Krüger, Rejko; Gharabaghi, Alireza

    2015-03-01

    Dynamic modulations of large-scale network activity and synchronization are inherent to a broad spectrum of cognitive processes and are disturbed in neuropsychiatric conditions including Parkinson's disease. Here, we set out to address the motor network activity and synchronization in Parkinson's disease and its modulation with subthalamic stimulation. To this end, 20 patients with idiopathic Parkinson's disease with subthalamic nucleus stimulation were analysed on externally cued right hand finger movements with 1.5-s interstimulus interval. Simultaneous recordings were obtained from electromyography on antagonistic muscles (right flexor digitorum and extensor digitorum) together with 64-channel electroencephalography. Time-frequency event-related spectral perturbations were assessed to determine cortical and muscular activity. Next, cross-spectra in the time-frequency domain were analysed to explore the cortico-cortical synchronization. The time-frequency modulations enabled us to select a time-frequency range relevant for motor processing. On these time-frequency windows, we developed an extension of the phase synchronization index to quantify the global cortico-cortical synchronization and to obtain topographic differentiations of distinct electrode sites with respect to their contributions to the global phase synchronization index. The spectral measures were used to predict clinical and reaction time outcome using regression analysis. We found that movement-related desynchronization of cortical activity in the upper alpha and beta range was significantly facilitated with 'stimulation on' compared to 'stimulation off' on electrodes over the bilateral parietal, sensorimotor, premotor, supplementary-motor, and prefrontal areas, including the bilateral inferior prefrontal areas. These spectral modulations enabled us to predict both clinical and reaction time improvement from subthalamic stimulation. With 'stimulation on', interhemispheric cortico-cortical

  15. Adrenal cortical and medullary imaging.

    PubMed

    Freitas, J E

    1995-07-01

    Adrenal disease can be manifested by endocrine dysfunction or anatomic abnormalities detected by cross-sectional imaging modalities. With the advent of newer and more reliable in vitro assays and a better understanding of the spectrum of adrenal pathology, the physician can now adopt a more accurate and cost-effective approach to the diagnosis of adrenal disease. Both functional and anatomic imaging modalities can play an important role in the evaluation of the incidental adrenal mass, the early detection of adrenal metastases, differentiation of the various causes of Cushings's syndrome, selection of patients for potentially curative surgery in primary aldosteronism and adrenal hyperandrogenism, and localization of pheochromocytomas and neuroblastomas. The usefulness of the adrenal cortical radiopharmaceutical, 131I-6-beta-iodomethylnorcholesterol (NP-59), and the adrenal medullary radiopharmaceuticals, 131I and 123I-metaiodobenzylguanidine (MIBG), is detailed for these various clinical settings and the role of NP-59 and MIBG is contrasted to that of the cross-sectional modalities, computed tomography and magnetic resonance imaging (MRI). Incidental adrenal masses are common, but malignancies are few. Imaging studies select those patients who require a further evaluation by biopsy examination or adrenalectomy. In the hyperfunctioning endocrine states, such as Cushing's syndrome, primary aldosteronism, adrenal androgenism, and pheochromocytoma, correlation of biochemical findings with both functional and anatomic imaging is necessary to avoid inappropriate and ineffective surgical intervention, yet not miss an opportunity for curative resection. Lastly, MIBG and MRI are complementary in the detection and staging of neuroblastoma.

  16. Cultured Human Renal Cortical Cells

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the STS-90 shuttle flight in April 1998, cultured renal cortical cells revealed new information about genes. Timothy Hammond, an investigator in NASA's microgravity biotechnology program was interested in culturing kidney tissue to study the expression of proteins useful in the treatment of kidney diseases. Protein expression is linked to the level of differentiation of the kidney cells, and Hammond had difficulty maintaining differentiated cells in vitro. Intrigued by the improvement in cell differentiation that he observed in rat renal cells cultured in NASA's rotating wall vessel (a bioreactor that simulates some aspects of microgravity) and during an experiment performed on the Russian Space Station Mir, Hammond decided to sleuth out which genes were responsible for controlling differentiation of kidney cells. To do this, he compared the gene activity of human renal cells in a variety of gravitational environments, including the microgravity of the space shuttle and the high-gravity environment of a centrifuge. Hammond found that 1,632 genes out of 10,000 analyzed changed their activity level in microgravity, more than in any of the other environments. These results have important implications for kidney research as well as for understanding the basic mechanism for controlling cell differentiation.

  17. Cultured Human Renal Cortical Cells

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the STS-90 shuttle flight in April 1998, cultured renal cortical cells revealed new information about genes. Timothy Hammond, an investigator in NASA's microgravity biotechnology program was interested in culturing kidney tissue to study the expression of proteins useful in the treatment of kidney diseases. Protein expression is linked to the level of differentiation of the kidney cells, and Hammond had difficulty maintaining differentiated cells in vitro. Intrigued by the improvement in cell differentiation that he observed in rat renal cells cultured in NASA's rotating wall vessel (a bioreactor that simulates some aspects of microgravity) and during an experiment performed on the Russian Space Station Mir, Hammond decided to sleuth out which genes were responsible for controlling differentiation of kidney cells. To do this, he compared the gene activity of human renal cells in a variety of gravitational environments, including the microgravity of the space shuttle and the high-gravity environment of a centrifuge. Hammond found that 1,632 genes out of 10,000 analyzed changed their activity level in microgravity, more than in any of the other environments. These results have important implications for kidney research as well as for understanding the basic mechanism for controlling cell differentiation.

  18. Cortical circuits for perceptual inference.

    PubMed

    Friston, Karl; Kiebel, Stefan

    2009-10-01

    This paper assumes that cortical circuits have evolved to enable inference about the causes of sensory input received by the brain. This provides a principled specification of what neural circuits have to achieve. Here, we attempt to address how the brain makes inferences by casting inference as an optimisation problem. We look at how the ensuing recognition dynamics could be supported by directed connections and message-passing among neuronal populations, given our knowledge of intrinsic and extrinsic neuronal connections. We assume that the brain models the world as a dynamic system, which imposes causal structure on the sensorium. Perception is equated with the optimisation or inversion of this internal model, to explain sensory input. Given a model of how sensory data are generated, we use a generic variational approach to model inversion to furnish equations that prescribe recognition; i.e., the dynamics of neuronal activity that represents the causes of sensory input. Here, we focus on a model whose hierarchical and dynamical structure enables simulated brains to recognise and predict sequences of sensory states. We first review these models and their inversion under a variational free-energy formulation. We then show that the brain has the necessary infrastructure to implement this inversion and present stimulations using synthetic birds that generate and recognise birdsongs.

  19. Broadband cortical desynchronization underlies the human psychedelic state.

    PubMed

    Muthukumaraswamy, Suresh D; Carhart-Harris, Robin L; Moran, Rosalyn J; Brookes, Matthew J; Williams, Tim M; Errtizoe, David; Sessa, Ben; Papadopoulos, Andreas; Bolstridge, Mark; Singh, Krish D; Feilding, Amanda; Friston, Karl J; Nutt, David J

    2013-09-18

    Psychedelic drugs produce profound changes in consciousness, but the underlying neurobiological mechanisms for this remain unclear. Spontaneous and induced oscillatory activity was recorded in healthy human participants with magnetoencephalography after intravenous infusion of psilocybin--prodrug of the nonselective serotonin 2A receptor agonist and classic psychedelic psilocin. Psilocybin reduced spontaneous cortical oscillatory power from 1 to 50 Hz in posterior association cortices, and from 8 to 100 Hz in frontal association cortices. Large decreases in oscillatory power were seen in areas of the default-mode network. Independent component analysis was used to identify a number of resting-state networks, and activity in these was similarly decreased after psilocybin. Psilocybin had no effect on low-level visually induced and motor-induced gamma-band oscillations, suggesting that some basic elements of oscillatory brain activity are relatively preserved during the psychedelic experience. Dynamic causal modeling revealed that posterior cingulate cortex desynchronization can be explained by increased excitability of deep-layer pyramidal neurons, which are known to be rich in 5-HT2A receptors. These findings suggest that the subjective effects of psychedelics result from a desynchronization of ongoing oscillatory rhythms in the cortex, likely triggered by 5-HT2A receptor-mediated excitation of deep pyramidal cells.

  20. Plasticity of recurring spatiotemporal activity patterns in cortical networks

    NASA Astrophysics Data System (ADS)

    Madhavan, Radhika; Chao, Zenas C.; Potter, Steve M.

    2007-09-01

    How do neurons encode and store information for long periods of time? Recurring patterns of activity have been reported in various cortical structures and were suggested to play a role in information processing and memory. To study the potential role of bursts of action potentials in memory mechanisms, we investigated patterns of spontaneous multi-single-unit activity in dissociated rat cortical cultures in vitro. Spontaneous spikes were recorded from networks of approximately 50 000 neurons and glia cultured on a grid of 60 extracellular substrate- embedded electrodes (multi-electrode arrays). These networks expressed spontaneous culture- wide bursting from approximately one week in vitro. During bursts, a large portion of the active electrodes showed elevated levels of firing. Spatiotemporal activity patterns within spontaneous bursts were clustered using a correlation-based clustering algorithm, and the occurrences of these burst clusters were tracked over several hours. This analysis revealed spatiotemporally diverse bursts occurring in well-defined patterns, which remained stable for several hours. Activity evoked by strong local tetanic stimulation resulted in significant changes in the occurrences of spontaneous bursts belonging to different clusters, indicating that the dynamical flow of information in the neuronal network had been altered. The diversity of spatiotemporal structure and long-term stability of spontaneous bursts together with their plastic nature strongly suggests that such network patterns could be used as codes for information transfer and the expression of memories stored in cortical networks.

  1. Dendritic Excitability and Gain Control in Recurrent Cortical Microcircuits

    PubMed Central

    Hay, Etay; Segev, Idan

    2015-01-01

    Layer 5 thick tufted pyramidal cells (TTCs) in the neocortex are particularly electrically complex, owing to their highly excitable dendrites. The interplay between dendritic nonlinearities and recurrent cortical microcircuit activity in shaping network response is largely unknown. We simulated detailed conductance-based models of TTCs forming recurrent microcircuits that were interconnected as found experimentally; the network was embedded in a realistic background synaptic activity. TTCs microcircuits significantly amplified brief thalamocortical inputs; this cortical gain was mediated by back-propagation activated N-methyl-d-aspartate depolarizations and dendritic back-propagation-activated Ca2+ spike firing, ignited by the coincidence of thalamic-activated somatic spike and local dendritic synaptic inputs, originating from the cortical microcircuit. Surprisingly, dendritic nonlinearities in TTCs microcircuits linearly multiplied thalamic inputs—amplifying them while maintaining input selectivity. Our findings indicate that dendritic nonlinearities are pivotal in controlling the gain and the computational functions of TTCs microcircuits, which serve as a dominant output source for the neocortex. PMID:25205662

  2. [The development of adrenal cortical hormones into drugs].

    PubMed

    Hansen, Sven Erik

    2008-01-01

    The interplay of factors contributing to the development of adrenal cortical hormones into drugs is reviewed. Clinical research performed during long periods by the physicians T. Addison and P.S. Hench in a nearly obsessional way stimulated basic research in physiology and biochemistry of the adrenal glands. From about 1900 increasing public interest in the "new hormones"coincided with expansion in research and development in academic and industrial settings. Pharmaceutical companies developed skill by production of much demanded organ-extracts, both effective ones as insulin and preparations of questionable clinical value. In 1949 the powerful anti-inflammatory effect of the cortical hormone, cortisone was discovered. As the supply of that hormone was scanty, it had temporarily to be substituted by the adrenocorticotropic hormone (ACTH) from animal hypophyses. Thereafter development accelerated through the combined effect of many years' painstaking research on the adrenal cortical hormones, technological breakthroughs, a climate positive for bold clinical experimentation and vigorous competition among mainly American pharmaceutical companies. Within a decade prednisone, the successor of cortisone, was launched, its clinical use established and large-scale inexpensive production instituted.

  3. Root cortical burden influences drought tolerance in maize

    PubMed Central

    Jaramillo, Raúl E.; Nord, Eric A.; Chimungu, Joseph G.; Brown, Kathleen M.; Lynch, Jonathan P.

    2013-01-01

    Background and Aims Root cortical aerenchyma (RCA) increases water and nutrient acquisition by reducing the metabolic costs of soil exploration. In this study the hypothesis was tested that living cortical area (LCA; transversal root cortical area minus aerenchyma area and intercellular air space) is a better predictor of root respiration, soil exploration and, therefore, drought tolerance than RCA formation or root diameter. Methods RCA, LCA, root respiration, root length and biomass loss in response to drought were evaluated in maize (Zea mays) recombinant inbred lines grown with adequate and suboptimal irrigation in soil mesocosms. Key Results Root respiration was highly correlated with LCA. LCA was a better predictor of root respiration than either RCA or root diameter. RCA reduced respiration of large-diameter roots. Since RCA and LCA varied in different parts of the root system, the effects of RCA and LCA on root length were complex. Greater crown-root LCA was associated with reduced crown-root length relative to total root length. Reduced LCA was associated with improved drought tolerance. Conclusions The results are consistent with the hypothesis that LCA is a driver of root metabolic costs and may therefore have adaptive significance for water acquisition in drying soil. PMID:23618897

  4. Realignment of interaural cortical maps in asymmetric hearing loss.

    PubMed

    Cheung, Steven W; Bonham, Ben H; Schreiner, Christoph E; Godey, Benoit; Copenhaver, David A

    2009-05-27

    Misalignment of interaural cortical response maps in asymmetric hearing loss evolves from initial gross divergence to near convergence over a 6 month recovery period. The evolution of left primary auditory cortex (AI) interaural frequency map changes is chronicled in squirrel monkeys with asymmetric hearing loss induced by overstimulating the right ear with a 1 kHz tone at 136 dB for 3 h. AI frequency response areas (FRAs), derived from tone bursts presented to the poorer or better hearing ears, are compared at 6, 12, and 24 weeks after acoustic overstimulation. Characteristic frequency (CF) and minimum threshold parameters are extracted from FRAs, and they are used to quantify interaural response map differences. A large interaural CF map misalignment of DeltaCF approximately 1.27 octaves at 6 weeks after overstimulation decreases substantially to DeltaCF approximately 0.62 octave at 24 weeks. Interaural cortical threshold map misalignment faithfully reflects peripheral asymmetric hearing loss at 6 and 12 weeks. However, AI threshold map misalignment essentially disappears at 24 weeks, primarily because ipsilateral cortical thresholds have become unexpectedly elevated relative to peripheral thresholds. The findings document that plastic change in central processing of sound stimuli arriving from the nominally better hearing ear may account for progressive realignment of both interaural frequency and threshold maps.

  5. Cortical encoding of pitch: recent results and open questions.

    PubMed

    Walker, Kerry M M; Bizley, Jennifer K; King, Andrew J; Schnupp, Jan W H

    2011-01-01

    It is widely appreciated that the key predictor of the pitch of a sound is its periodicity. Neural structures which support pitch perception must therefore be able to reflect the repetition rate of a sound, but this alone is not sufficient. Since pitch is a psychoacoustic property, a putative cortical code for pitch must also be able to account for the relationship between the amount to which a sound is periodic (i.e. its temporal regularity) and the perceived pitch salience, as well as limits in our ability to detect pitch changes or to discriminate rising from falling pitch. Pitch codes must also be robust in the presence of nuisance variables such as loudness or timbre. Here, we review a large body of work on the cortical basis of pitch perception, which illustrates that the distribution of cortical processes that give rise to pitch perception is likely to depend on both the acoustical features and functional relevance of a sound. While previous studies have greatly advanced our understanding, we highlight several open questions regarding the neural basis of pitch perception. These questions can begin to be addressed through a cooperation of investigative efforts across species and experimental techniques, and, critically, by examining the responses of single neurons in behaving animals. © 2010 Elsevier B.V. All rights reserved.

  6. Cortical encoding of pitch: Recent results and open questions

    PubMed Central

    Walker, Kerry M.M.; Bizley, Jennifer K.; King, Andrew J.; Schnupp, Jan W.H.

    2011-01-01

    It is widely appreciated that the key predictor of the pitch of a sound is its periodicity. Neural structures which support pitch perception must therefore be able to reflect the repetition rate of a sound, but this alone is not sufficient. Since pitch is a psychoacoustic property, a putative cortical code for pitch must also be able to account for the relationship between the amount to which a sound is periodic (i.e. its temporal regularity) and the perceived pitch salience, as well as limits in our ability to detect pitch changes or to discriminate rising from falling pitch. Pitch codes must also be robust in the presence of nuisance variables such as loudness or timbre. Here, we review a large body of work on the cortical basis of pitch perception, which illustrates that the distribution of cortical processes that give rise to pitch perception is likely to depend on both the acoustical features and functional relevance of a sound. While previous studies have greatly advanced our understanding, we highlight several open questions regarding the neural basis of pitch perception. These questions can begin to be addressed through a cooperation of investigative efforts across species and experimental techniques, and, critically, by examining the responses of single neurons in behaving animals. PMID:20457240

  7. Cortical High-Density Counterstream Architectures

    PubMed Central

    Markov, Nikola T.; Ercsey-Ravasz, Mária; Van Essen, David C.

    2014-01-01

    Small-world networks provide an appealing description of cortical architecture owing to their capacity for integration and segregation combined with an economy of connectivity. Previous reports of low-density interareal graphs and apparent small-world properties are challenged by data that reveal high-density cortical graphs in which economy of connections is achieved by weight heterogeneity and distance-weight correlations. These properties define a model that predicts many binary and weighted features of the cortical network including a core-periphery, a typical feature of self-organizing information processing systems. Feedback and feedforward pathways between areas exhibit a dual counterstream organization, and their integration into local circuits constrains cortical computation. Here, we propose a bow-tie representation of interareal architecture derived from the hierarchical laminar weights of pathways between the high-efficiency dense core and periphery. PMID:24179228

  8. Cortical high-density counterstream architectures.

    PubMed

    Markov, Nikola T; Ercsey-Ravasz, Mária; Van Essen, David C; Knoblauch, Kenneth; Toroczkai, Zoltán; Kennedy, Henry

    2013-11-01

    Small-world networks provide an appealing description of cortical architecture owing to their capacity for integration and segregation combined with an economy of connectivity. Previous reports of low-density interareal graphs and apparent small-world properties are challenged by data that reveal high-density cortical graphs in which economy of connections is achieved by weight heterogeneity and distance-weight correlations. These properties define a model that predicts many binary and weighted features of the cortical network including a core-periphery, a typical feature of self-organizing information processing systems. Feedback and feedforward pathways between areas exhibit a dual counterstream organization, and their integration into local circuits constrains cortical computation. Here, we propose a bow-tie representation of interareal architecture derived from the hierarchical laminar weights of pathways between the high-efficiency dense core and periphery.

  9. High-Degree Neurons Feed Cortical Computations.

    PubMed

    Timme, Nicholas M; Ito, Shinya; Myroshnychenko, Maxym; Nigam, Sunny; Shimono, Masanori; Yeh, Fang-Chin; Hottowy, Pawel; Litke, Alan M; Beggs, John M

    2016-05-01

    Recent work has shown that functional connectivity among cortical neurons is highly varied, with a small percentage of neurons having many more connections than others. Also, recent theoretical developments now make it possible to quantify how neurons modify information from the connections they receive. Therefore, it is now possible to investigate how information modification, or computation, depends on the number of connections a neuron receives (in-degree) or sends out (out-degree). To do this, we recorded the simultaneous spiking activity of hundreds of neurons in cortico-hippocampal slice cultures using a high-density 512-electrode array. This preparation and recording method combination produced large numbers of neurons recorded at temporal and spatial resolutions that are not currently available in any in vivo recording system. We utilized transfer entropy (a well-established method for detecting linear and nonlinear interactions in time series) and the partial information decomposition (a powerful, recently developed tool for dissecting multivariate information processing into distinct parts) to quantify computation between neurons where information flows converged. We found that computations did not occur equally in all neurons throughout the networks. Surprisingly, neurons that computed large amounts of information tended to receive connections from high out-degree neurons. However, the in-degree of a neuron was not related to the amount of information it computed. To gain insight into these findings, we developed a simple feedforward network model. We found that a degree-modified Hebbian wiring rule best reproduced the pattern of computation and degree correlation results seen in the real data. Interestingly, this rule also maximized signal propagation in the presence of network-wide correlations, suggesting a mechanism by which cortex could deal with common random background input. These are the first results to show that the extent to which a neuron

  10. High-Degree Neurons Feed Cortical Computations

    PubMed Central

    Timme, Nicholas M.; Ito, Shinya; Shimono, Masanori; Yeh, Fang-Chin; Litke, Alan M.; Beggs, John M.

    2016-01-01

    Recent work has shown that functional connectivity among cortical neurons is highly varied, with a small percentage of neurons having many more connections than others. Also, recent theoretical developments now make it possible to quantify how neurons modify information from the connections they receive. Therefore, it is now possible to investigate how information modification, or computation, depends on the number of connections a neuron receives (in-degree) or sends out (out-degree). To do this, we recorded the simultaneous spiking activity of hundreds of neurons in cortico-hippocampal slice cultures using a high-density 512-electrode array. This preparation and recording method combination produced large numbers of neurons recorded at temporal and spatial resolutions that are not currently available in any in vivo recording system. We utilized transfer entropy (a well-established method for detecting linear and nonlinear interactions in time series) and the partial information decomposition (a powerful, recently developed tool for dissecting multivariate information processing into distinct parts) to quantify computation between neurons where information flows converged. We found that computations did not occur equally in all neurons throughout the networks. Surprisingly, neurons that computed large amounts of information tended to receive connections from high out-degree neurons. However, the in-degree of a neuron was not related to the amount of information it computed. To gain insight into these findings, we developed a simple feedforward network model. We found that a degree-modified Hebbian wiring rule best reproduced the pattern of computation and degree correlation results seen in the real data. Interestingly, this rule also maximized signal propagation in the presence of network-wide correlations, suggesting a mechanism by which cortex could deal with common random background input. These are the first results to show that the extent to which a neuron

  11. TDCS increases cortical excitability: direct evidence from TMS-EEG.

    PubMed

    Romero Lauro, Leonor J; Rosanova, Mario; Mattavelli, Giulia; Convento, Silvia; Pisoni, Alberto; Opitz, Alexander; Bolognini, Nadia; Vallar, Giuseppe

    2014-09-01

    Despite transcranial direct current stimulation (tDCS) is increasingly used in experimental and clinical settings, its precise mechanisms of action remain largely unknown. At a neuronal level, tDCS modulates the resting membrane potential in a polarity-dependent fashion: anodal stimulation increases cortical excitability in the stimulated region, while cathodal decreases it. So far, the neurophysiological underpinnings of the immediate and delayed effects of tDCS, and to what extent the stimulation of a given cerebral region may affect the activity of anatomically connected regions, remain unclear. In the present study, we used a combination of Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG) in order to explore local and global cortical excitability modulation during and after active and sham tDCS. Single pulse TMS was delivered over the left posterior parietal cortex (PPC), before, during, and after 15 min of tDCS over the right PPC, while EEG was recorded from 60 channels. For each session, indexes of global and local cerebral excitability were obtained, computed as global and local mean field power (Global Mean Field Power, GMFP and Local Mean Field Power, LMFP) on mean TMS-evoked potentials (TEPs) for three temporal windows: 0-50, 50-100, and 100-150 msec. The global index was computed on all 60 channels. The local indexes were computed in six clusters of electrodes: left and right in frontal, parietal and temporal regions. GMFP increased, compared to baseline, both during and after active tDCS in the 0-100 msec temporal window. LMFP increased after the end of stimulation in parietal and frontal clusters bilaterally, while no difference was found in the temporal clusters. In sum, a diffuse rise of cortical excitability occurred, both during and after active tDCS. This evidence highlights the spreading of the effects of anodal tDCS over remote cortical regions of stimulated and contralateral hemispheres.

  12. Mapping cortical change in Alzheimer's disease, brain development, and schizophrenia.

    PubMed

    Thompson, Paul M; Hayashi, Kiralee M; Sowell, Elizabeth R; Gogtay, Nitin; Giedd, Jay N; Rapoport, Judith L; de Zubicaray, Greig I; Janke, Andrew L; Rose, Stephen E; Semple, James; Doddrell, David M; Wang, Yalin; van Erp, Theo G M; Cannon, Tyrone D; Toga, Arthur W

    2004-01-01

    This paper describes algorithms that can identify patterns of brain structure and function associated with Alzheimer's disease, schizophrenia, normal aging, and abnormal brain development based on imaging data collected in large human populations. Extraordinary information can be discovered with these techniques: dynamic brain maps reveal how the brain grows in childhood, how it changes in disease, and how it responds to medication. Genetic brain maps can reveal genetic influences on brain structure, shedding light on the nature-nurture debate, and the mechanisms underlying inherited neurobehavioral disorders. Recently, we created time-lapse movies of brain structure for a variety of diseases. These identify complex, shifting patterns of brain structural deficits, revealing where, and at what rate, the path of brain deterioration in illness deviates from normal. Statistical criteria can then identify situations in which these changes are abnormally accelerated, or when medication or other interventions slow them. In this paper, we focus on describing our approaches to map structural changes in the cortex. These methods have already been used to reveal the profile of brain anomalies in studies of dementia, epilepsy, depression, childhood- and adult-onset schizophrenia, bipolar disorder, attention-deficit/hyperactivity disorder, fetal alcohol syndrome, Tourette syndrome, Williams syndrome, and in methamphetamine abusers. Specifically, we describe an image analysis pipeline known as cortical pattern matching that helps compare and pool cortical data over time and across subjects. Statistics are then defined to identify brain structural differences between groups, including localized alterations in cortical thickness, gray matter density (GMD), and asymmetries in cortical organization. Subtle features, not seen in individual brain scans, often emerge when population-based brain data are averaged in this way. Illustrative examples are presented to show the profound

  13. The possible role of spike patterns in cortical information processing.

    PubMed

    Tiesinga, Paul H E; Toups, J Vincent

    2005-06-01

    When the same visual stimulus is presented across many trials, neurons in the visual cortex receive stimulus-related synaptic inputs that are reproducible across trials (S) and inputs that are not (N). The variability of spike trains recorded in the visual cortex and their apparent lack of spike-to-spike correlations beyond that implied by firing rate fluctuations, has been taken as evidence for a low S/N ratio. A recent re-analysis of in vivo cortical data revealed evidence for spike-to-spike correlations in the form of spike patterns. We examine neural dynamics at a higher S/N in order to determine what possible role spike patterns could play in cortical information processing. In vivo-like spike patterns were obtained in model simulations. Superpositions of multiple sinusoidal driving currents were especially effective in producing stable long-lasting patterns. By applying current pulses that were either short and strong or long and weak, neurons could be made to switch from one pattern to another. Cortical neurons with similar stimulus preferences are located near each other, have similar biophysical properties and receive a large number of common synaptic inputs. Hence, recordings of a single neuron across multiple trials are usually interpreted as the response of an ensemble of these neurons during one trial. In the presence of distinct spike patterns across trials there is ambiguity in what would be the corresponding ensemble, it could consist of the same spike pattern for each neuron or a set of patterns across neurons. We found that the spiking response of a neuron receiving these ensemble inputs was determined by the spike-pattern composition, which, in turn, could be modulated dynamically as a means for cortical information processing.

  14. Sensorimotor modulation of human cortical swallowing pathways.

    PubMed

    Hamdy, S; Aziz, Q; Rothwell, J C; Hobson, A; Thompson, D G

    1998-02-01

    1. Transcranial magnetic stimulation over motor areas of cerebral cortex in man can activate short latency bilateral cortical projections to the pharynx and oesophagus. In the present paper we investigate the interaction between pathways from each hemisphere and explore how activity in these pathways is modulated by afferent feedback from the face, pharynx and oesophagus. 2. Comparison of unilateral and bilateral stimulation (using interstimulus intervals (ISIs) of 1, 5 or 10 ms between shocks) showed spatial summation of responses from each hemisphere at an ISI of 1 ms, indicating that cortical efferents project onto a shared population of target neurones. Such summation was not evident at ISIs of 5 or 10 ms. There was little evidence for transcallosal inhibition of responses from each hemisphere, as described for limb muscles. 3. Single stimuli applied to the vagus nerve in the neck or the supraorbital nerve, which alone produce intermediate (onset 20-30 ms) and long (50-70 ms) latency reflex responses in the pharynx and oesophagus, were used to condition the cortical responses. Compared with rest, responses evoked by cortical stimulation were facilitated when they were timed to coincide with the late part of the reflex. The onset latency was reduced during both parts of the reflex response. No facilitation was observed with subthreshold reflex stimuli. 4. Single electrical stimuli applied to the pharynx or oesophagus had no effect on the response to cortical stimulation. However, trains of stimuli at frequencies varying from 0.2 to 10 Hz decreased the latency of the cortically evoked responses without consistently influencing their amplitudes. The effect was site specific: pharyngeal stimulation shortened both pharyngeal and oesophageal response latencies, whereas oesophageal stimulation shortened only the oesophageal response latencies. 5. Cortical swallowing motor pathways from each hemisphere interact and their excitability is modulated in a site

  15. Sensorimotor modulation of human cortical swallowing pathways

    PubMed Central

    Hamdy, Shaheen; Aziz, Qasim; Rothwell, John C; Hobson, Anthony; Thompson, David G

    1998-01-01

    Transcranial magnetic stimulation over motor areas of cerebral cortex in man can activate short latency bilateral cortical projections to the pharynx and oesophagus. In the present paper we investigate the interaction between pathways from each hemisphere and explore how activity in these pathways is modulated by afferent feedback from the face, pharynx and oesophagus.Comparison of unilateral and bilateral stimulation (using interstimulus intervals (ISIs) of 1, 5 or 10 ms between shocks) showed spatial summation of responses from each hemisphere at an ISI of 1 ms, indicating that cortical efferents project onto a shared population of target neurones. Such summation was not evident at ISIs of 5 or 10 ms. There was little evidence for transcallosal inhibition of responses from each hemisphere, as described for limb muscles.Single stimuli applied to the vagus nerve in the neck or the supraorbital nerve, which alone produce intermediate (onset 20-30 ms) and long (50-70 ms) latency reflex responses in the pharynx and oesophagus, were used to condition the cortical responses. Compared with rest, responses evoked by cortical stimulation were facilitated when they were timed to coincide with the late part of the reflex. The onset latency was reduced during both parts of the reflex response. No facilitation was observed with subthreshold reflex stimuli.Single electrical stimuli applied to the pharynx or oesophagus had no effect on the response to cortical stimulation. However, trains of stimuli at frequencies varying from 0.2 to 10 Hz decreased the latency of the cortically evoked responses without consistently influencing their amplitudes. The effect was site specific: pharyngeal stimulation shortened both pharyngeal and oesophageal response latencies, whereas oesophageal stimulation shortened only the oesophageal response latencies.Cortical swallowing motor pathways from each hemisphere interact and their excitability is modulated in a site-specific manner by sensory

  16. CLADA: cortical longitudinal atrophy detection algorithm.

    PubMed

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2011-01-01

    Measurement of changes in brain cortical thickness is useful for the assessment of regional gray matter atrophy in neurodegenerative conditions. A new longitudinal method, called CLADA (cortical longitudinal atrophy detection algorithm), has been developed for the measurement of changes in cortical thickness in magnetic resonance images (MRI) acquired over time. CLADA creates a subject-specific cortical model which is longitudinally deformed to match images from individual time points. The algorithm was designed to work reliably for lower resolution images, such as the MRIs with 1×1×5 mm(3) voxels previously acquired for many clinical trials in multiple sclerosis (MS). CLADA was evaluated to determine reproducibility, accuracy, and sensitivity. Scan-rescan variability was 0.45% for images with 1mm(3) isotropic voxels and 0.77% for images with 1×1×5 mm(3) voxels. The mean absolute accuracy error was 0.43 mm, as determined by comparison of CLADA measurements to cortical thickness measured directly in post-mortem tissue. CLADA's sensitivity for correctly detecting at least 0.1mm change was 86% in a simulation study. A comparison to FreeSurfer showed good agreement (Pearson correlation=0.73 for global mean thickness). CLADA was also applied to MRIs acquired over 18 months in secondary progressive MS patients who were imaged at two different resolutions. Cortical thinning was detected in this group in both the lower and higher resolution images. CLADA detected a higher rate of cortical thinning in MS patients compared to healthy controls over 2 years. These results show that CLADA can be used for reliable measurement of cortical atrophy in longitudinal studies, even in lower resolution images.

  17. CLADA: Cortical Longitudinal Atrophy Detection Algorithm

    PubMed Central

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2010-01-01

    Measurement of changes in brain cortical thickness is useful for assessment of regional gray matter atrophy in neurodegenerative conditions. A new longitudinal method, called CLADA (cortical longitudinal atrophy detection algorithm), has been developed for measurement of changes in cortical thickness in magnetic resonance images (MRI) acquired over time. CLADA creates a subject-specific cortical model which is longitudinally deformed to match images from individual time points. The algorithm was designed to work reliably for lower-resolution images, such as the MRIs with 1×1×5mm3 voxels previously acquired for many clinical trials in multiple sclerosis (MS). CLADA was evaluated to determine reproducibility, accuracy, and sensitivity. Scan-rescan variability was 0.45% for images with 1mm3 isotropic voxels and 0.77% for images with 1×1×5 mm3 voxels. The mean absolute accuracy error was 0.43 mm, as determined by comparison of CLADA measurements to cortical thickness measured directly in post- mortem tissue. CLADA’s sensitivity for correctly detecting at least 0.1 mm change was 86% in a simulation study. A comparison to FreeSurfer showed good agreement (Pearson correlation = 0.73 for global mean thickness). CLADA was also applied to MRIs acquired over 18 months in secondary progressive MS patients who were imaged at two different resolutions. Cortical thinning was detected in this group in both the lower and higher resolution images. CLADA detected a higher rate of cortical thinning in MS patients compared to healthy controls over 2 years. These results show that CLADA can be used for reliable measurement of cortical atrophy in longitudinal studies, even in lower resolution images. PMID:20674750

  18. Cortical Depth Dependence of the Diffusion Anisotropy in the Human Cortical Gray Matter In Vivo

    PubMed Central

    Truong, Trong-Kha; Guidon, Arnaud; Song, Allen W.

    2014-01-01

    Diffusion tensor imaging (DTI) is typically used to study white matter fiber pathways, but may also be valuable to assess the microstructure of cortical gray matter. Although cortical diffusion anisotropy has previously been observed in vivo, its cortical depth dependence has mostly been examined in high-resolution ex vivo studies. This study thus aims to investigate the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo on a clinical 3 T scanner. Specifically, a novel multishot constant-density spiral DTI technique with inherent correction of motion-induced phase errors was used to achieve a high spatial resolution (0.625×0.625×3 mm) and high spatial fidelity with no scan time penalty. The results show: (i) a diffusion anisotropy in the cortical gray matter, with a primarily radial diffusion orientation, as observed in previous ex vivo and in vivo studies, and (ii) a cortical depth dependence of the fractional anisotropy, with consistently higher values in the middle cortical lamina than in the deep and superficial cortical laminae, as observed in previous ex vivo studies. These results, which are consistent across subjects, demonstrate the feasibility of this technique for investigating the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo. PMID:24608869

  19. Cortical depth dependence of the diffusion anisotropy in the human cortical gray matter in vivo.

    PubMed

    Truong, Trong-Kha; Guidon, Arnaud; Song, Allen W

    2014-01-01

    Diffusion tensor imaging (DTI) is typically used to study white matter fiber pathways, but may also be valuable to assess the microstructure of cortical gray matter. Although cortical diffusion anisotropy has previously been observed in vivo, its cortical depth dependence has mostly been examined in high-resolution ex vivo studies. This study thus aims to investigate the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo on a clinical 3 T scanner. Specifically, a novel multishot constant-density spiral DTI technique with inherent correction of motion-induced phase errors was used to achieve a high spatial resolution (0.625 × 0.625 × 3 mm) and high spatial fidelity with no scan time penalty. The results show: (i) a diffusion anisotropy in the cortical gray matter, with a primarily radial diffusion orientation, as observed in previous ex vivo and in vivo studies, and (ii) a cortical depth dependence of the fractional anisotropy, with consistently higher values in the middle cortical lamina than in the deep and superficial cortical laminae, as observed in previous ex vivo studies. These results, which are consistent across subjects, demonstrate the feasibility of this technique for investigating the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo.

  20. The cortical and sub-cortical network of sensory evoked response in healthy subjects.

    PubMed

    Muthuraman, M; Hellriegel, H; Groppa, S; Deuschl, G; Raethjen, J

    2013-01-01

    The aim of this study was to find the cortical and sub-cortical network responsible for the sensory evoked coherence in healthy subjects during electrical stimulation of right median nerve at wrist. The multitaper method was used to estimate the power and coherence spectrum followed by the source analysis method dynamic imaging of coherent sources (DICS) to find the highest coherent source for the basic frequency 3 Hz and the complete cortical and sub-cortical network responsible for the sensory evoked coherence in healthy subjects. The highest coherent source for the basic frequency was in the posterior parietal cortex for all the subjects. The cortical and sub-cortical network comprised of the primary sensory motor cortex (SI), secondary sensory motor cortex (SII), frontal cortex and medial pulvinar nucleus in the thalamus. The cortical and sub-cortical network responsible for the sensory evoked coherence was found successfully with a 64-channel EEG system. The sensory evoked coherence is involved with a thalamo-cortical network in healthy subjects.

  1. Rich-Club Organization in Effective Connectivity among Cortical Neurons

    PubMed Central

    Shimono, Masanori; Ito, Shinya; Yeh, Fang-Chin; Timme, Nicholas; Myroshnychenko, Maxym; Lapish, Christopher C.; Tosi, Zachary; Hottowy, Pawel; Smith, Wesley C.; Masmanidis, Sotiris C.; Litke, Alan M.; Sporns, Olaf; Beggs, John M.

    2016-01-01

    The performance of complex networks, like the brain, depends on how effectively their elements communicate. Despite the importance of communication, it is virtually unknown how information is transferred in local cortical networks, consisting of hundreds of closely spaced neurons. To address this, it is important to record simultaneously from hundreds of neurons at a spacing that matches typical axonal connection distances, and at a temporal resolution that matches synaptic delays. We used a 512-electrode array (60 μm spacing) to record spontaneous activity at 20 kHz from up to 500 neurons simultaneously in slice cultures of mouse somatosensory cortex for 1 h at a time. We applied a previously validated version of transfer entropy to quantify information transfer. Similar to in vivo reports, we found an approximately lognormal distribution of firing rates. Pairwise information transfer strengths also were nearly lognormally distributed, similar to reports of synaptic strengths. Some neurons transferred and received much more information than others, which is consistent with previous predictions. Neurons with the highest outgoing and incoming information transfer were more strongly connected to each other than chance, thus forming a “rich club.” We found similar results in networks recorded in vivo from rodent cortex, suggesting the generality of these findings. A rich-club structure has been found previously in large-scale human brain networks and is thought to facilitate communication between cortical regions. The discovery of a small, but information-rich, subset of neurons within cortical regions suggests that this population will play a vital role in communication, learning, and memory. SIGNIFICANCE STATEMENT Many studies have focused on communication networks between cortical brain regions. In contrast, very few studies have examined communication networks within a cortical region. This is the first study to combine such a large number of neurons (several

  2. Cortical thinning in former professional soccer players.

    PubMed

    Koerte, Inga K; Mayinger, Michael; Muehlmann, Marc; Kaufmann, David; Lin, Alexander P; Steffinger, Denise; Fisch, Barbara; Rauchmann, Boris-Stephan; Immler, Stefanie; Karch, Susanne; Heinen, Florian R; Ertl-Wagner, Birgit; Reiser, Maximilian; Stern, Robert A; Zafonte, Ross; Shenton, Martha E

    2016-09-01

    Soccer is the most popular sport in the world. Soccer players are at high risk for repetitive subconcussive head impact when heading the ball. Whether this leads to long-term alterations of the brain's structure associated with cognitive decline remains unknown. The aim of this study was to evaluate cortical thickness in former professional soccer players using high-resolution structural MR imaging. Fifteen former male professional soccer players (mean age 49.3 [SD 5.1] years) underwent high-resolution structural 3 T MR imaging, as well as cognitive testing. Fifteen male, age-matched former professional non-contact sport athletes (mean age 49.6 [SD 6.4] years) served as controls. Group analyses of cortical thickness were performed using voxel-based statistics. Soccer players demonstrated greater cortical thinning with increasing age compared to controls in the right inferolateral-parietal, temporal, and occipital cortex. Cortical thinning was associated with lower cognitive performance as well as with estimated exposure to repetitive subconcussive head impact. Neurocognitive evaluation revealed decreased memory performance in the soccer players compared to controls. The association of cortical thinning and decreased cognitive performance, as well as exposure to repetitive subconcussive head impact, further supports the hypothesis that repetitive subconcussive head impact may play a role in early cognitive decline in soccer players. Future studies are needed to elucidate the time course of changes in cortical thickness as well as their association with impaired cognitive function and possible underlying neurodegenerative process.

  3. Development and evolution of cortical fields.

    PubMed

    Arai, Yoko; Pierani, Alessandra

    2014-09-01

    The neocortex is the brain structure that has been subjected to a major size expansion, in its relative size, during mammalian evolution. It arises from the cortical primordium through coordinated growth of neural progenitor cells along both the tangential and radial axes and their patterning providing spatial coordinates. Functional neocortical areas are ultimately consolidated by environmental influences such as peripheral sensory inputs. Throughout neocortical evolution, cortical areas have become more sophisticated and numerous. This increase in number is possibly involved in the complexification of neocortical function in primates. Whereas extensive divergence of functional cortical fields is observed during evolution, the fundamental mechanisms supporting the allocation of cortical areas and their wiring are conserved, suggesting the presence of core genetic mechanisms operating in different species. We will discuss some of the basic molecular mechanisms including morphogen-dependent ones involved in the precise orchestration of neurogenesis in different cortical areas, elucidated from studies in rodents. Attention will be paid to the role of Cajal-Retzius neurons, which were recently proposed to be migrating signaling units also involved in arealization, will be addressed. We will further review recent works on molecular mechanisms of cortical patterning resulting from comparative analyses between different species during evolution. Copyright © 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  4. Elastic Properties of Chimpanzee Craniofacial Cortical Bone.

    PubMed

    Gharpure, Poorva; Kontogiorgos, Elias D; Opperman, Lynne A; Ross, Callum F; Strait, David S; Smith, Amanda; Pryor, Leslie C; Wang, Qian; Dechow, Paul C

    2016-12-01

    Relatively few assessments of cranial biomechanics formally take into account variation in the material properties of cranial cortical bone. Our aim was to characterize the elastic properties of chimpanzee craniofacial cortical bone and compare these to the elastic properties of dentate human craniofacial cortical bone. From seven cranial regions, 27 cylindrical samples were harvested from each of five chimpanzee crania. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived using modified equations of Hooke's law in a Mathcad program. Consistent orientations among individuals were observed in the zygomatic arch and alveolus. The density of cortical bone showed significant regional variation (P < 0.001). The elastic moduli demonstrated significant differences between sites, and a distinct pattern where E3  > E2  > E1 . Shear moduli were significantly different among regions (P < 0.001). The pattern by which chimpanzee cranial cortical bone varies in elastic properties resembled that seen in humans, perhaps suggesting that the elastic properties of craniofacial bone in fossil hominins can be estimated with at least some degree of confidence. Anat Rec, 299:1718-1733, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Reduced Cortical Thickness in Mental Retardation

    PubMed Central

    Wang, Chao; Wang, Jiaojian; Zhang, Yun; Yu, Chunshui; Jiang, Tianzi

    2011-01-01

    Mental retardation is a developmental disorder associated with impaired cognitive functioning and deficits in adaptive behaviors. Many studies have addressed white matter abnormalities in patients with mental retardation, while the changes of the cerebral cortex have been studied to a lesser extent. Quantitative analysis of cortical integrity using cortical thickness measurement may provide new insights into the gray matter pathology. In this study, cortical thickness was compared between 13 patients with mental retardation and 26 demographically matched healthy controls. We found that patients with mental retardation had significantly reduced cortical thickness in multiple brain regions compared with healthy controls. These regions include the bilateral lingual gyrus, the bilateral fusiform gyrus, the bilateral parahippocampal gyrus, the bilateral temporal pole, the left inferior temporal gyrus, the right lateral orbitofrontal cortex and the right precentral gyrus. The observed cortical thickness reductions might be the anatomical substrates for the impaired cognitive functioning and deficits in adaptive behaviors in patients with mental retardation. Cortical thickness measurement might provide a sensitive prospective surrogate marker for clinical trials of neuroprotective medications. PMID:22216343

  6. Functional Connectivity in Multiple Cortical Networks Is Associated with Performance Across Cognitive Domains in Older Adults

    PubMed Central

    Shaw, Emily E.; Schultz, Aaron P.; Sperling, Reisa A.

    2015-01-01

    Abstract Intrinsic functional connectivity MRI has become a widely used tool for measuring integrity in large-scale cortical networks. This study examined multiple cortical networks using Template-Based Rotation (TBR), a method that applies a priori network and nuisance component templates defined from an independent dataset to test datasets of interest. A priori templates were applied to a test dataset of 276 older adults (ages 65–90) from the Harvard Aging Brain Study to examine the relationship between multiple large-scale cortical networks and cognition. Factor scores derived from neuropsychological tests represented processing speed, executive function, and episodic memory. Resting-state BOLD data were acquired in two 6-min acquisitions on a 3-Tesla scanner and processed with TBR to extract individual-level metrics of network connectivity in multiple cortical networks. All results controlled for data quality metrics, including motion. Connectivity in multiple large-scale cortical networks was positively related to all cognitive domains, with a composite measure of general connectivity positively associated with general cognitive performance. Controlling for the correlations between networks, the frontoparietal control network (FPCN) and executive function demonstrated the only significant association, suggesting specificity in this relationship. Further analyses found that the FPCN mediated the relationships of the other networks with cognition, suggesting that this network may play a central role in understanding individual variation in cognition during aging. PMID:25827242

  7. LRP12 silencing during brain development results in cortical dyslamination and seizure sensitization.

    PubMed

    Grote, Alexander; Robens, Barbara K; Blümcke, Ingmar; Becker, Albert J; Schoch, Susanne; Gembé, Eva

    2016-02-01

    Correct positioning and differentiation of neurons during brain development is a key precondition for proper function. Focal cortical dysplasias (FCDs) are increasingly recognized as causes of therapy refractory epilepsies. Neuropathological analyses of respective surgical specimens from neurosurgery for seizure control often reveal aberrant cortical architecture and/or aberrantly shaped neurons in FCDs. However, the molecular pathogenesis particularly of FCDs with aberrant lamination (so-called FCD type I) is largely unresolved. Lipoproteins and particularly low-density lipoprotein receptor-related protein 12 (LRP12) are involved in brain development. Here, we have examined a potential role of LRP12 in the pathogenesis of FCDs. In vitro knockdown of LRP12 in primary neurons results in impaired neuronal arborization. In vivo ablation of LRP12 by intraventricularly in utero electroporated shRNAs elicits cortical maldevelopment, i.e. aberrant lamination by malpositioning of upper cortical layer neurons. Subsequent epilepsy phenotyping revealed pentylenetetrazol (PTZ)-induced seizures to be aggravated in cortical LRP12-silenced mice. Our data demonstrates IUE mediated cortical gene silencing as an excellent approach to study the role of distinct molecules for epilepsy associated focal brain lesions and suggests LRP12 and lipoprotein homeostasis as potential molecular target structures for the emergence of epilepsy-associated FCDs. Copyright © 2015. Published by Elsevier Inc.

  8. EEG sleep slow-wave activity as a mirror of cortical maturation.

    PubMed

    Buchmann, Andreas; Ringli, Maya; Kurth, Salomé; Schaerer, Margot; Geiger, Anja; Jenni, Oskar G; Huber, Reto

    2011-03-01

    Deep (slow wave) sleep shows extensive maturational changes from childhood through adolescence, which is reflected in a decrease of sleep depth measured as the activity of electroencephalographic (EEG) slow waves. This decrease in sleep depth is paralleled by massive synaptic remodeling during adolescence as observed in anatomical studies, which supports the notion that adolescence represents a sensitive period for cortical maturation. To assess the relationship between slow-wave activity (SWA) and cortical maturation, we acquired sleep EEG and magnetic resonance imaging data in children and adolescents between 8 and 19 years. We observed a tight relationship between sleep SWA and a variety of indexes of cortical maturation derived from magnetic resonance (MR) images. Specifically, gray matter volumes in regions correlating positively with the activity of slow waves largely overlapped with brain areas exhibiting an age-dependent decrease in gray matter. The positive relationship between SWA and cortical gray matter was present also for power in other frequency ranges (theta, alpha, sigma, and beta) and other vigilance states (theta during rapid eye movement sleep). Our findings indicate a strong relationship between sleep EEG activity and cortical maturation. We propose that in particular, sleep SWA represents a good marker for structural changes in neuronal networks reflecting cortical maturation during adolescence.

  9. Reassessing cortical reorganization in the primary sensorimotor cortex following arm amputation.

    PubMed

    Makin, Tamar R; Scholz, Jan; Henderson Slater, David; Johansen-Berg, Heidi; Tracey, Irene

    2015-08-01

    The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, despite its growing popularity, the evidence to support the maladaptive plasticity theory is largely based on correlations between pain ratings and oftentimes crude measurements of cortical reorganization, with little consideration of potential contributions of other clinical factors, such as adaptive behaviour, in driving the identified brain plasticity. Here, we used a physiologically meaningful measurement of cortical reorganization to reassess its relationship to phantom pain in upper limb amputees. We identified small yet consistent shifts in lip representation contralateral to the missing hand towards, but not invading, the hand area. However, we were unable to identify any statistical relationship between cortical reorganization and phantom sensations or pain either with this measurement or with the traditional Euclidian distance measurement. Instead, we demonstrate that other factors may contribute to the observed remapping. Further research that reassesses more broadly the relationship between cortical reorganization and chronic pain is warranted.

  10. Coronary artery calcium is associated with cortical thinning in cognitively normal individuals

    PubMed Central

    Lee, Jin San; Kang, Danbee; Jang, Young Kyoung; Kim, Hee Jin; Na, Duk L.; Shin, Hee Young; Kang, Mira; Yang, Jin-Ju; Lee, Jong-Min; Lee, Juyoun; Kim, Yeo Jin; Park, Key-Chung; Guallar, Eliseo; Seo, Sang Won; Cho, Juhee

    2016-01-01

    To evaluate the association between coronary artery calcium (CAC) and cortical thickness in a large sample of cognitively normal individuals, with special emphasis in determining if the association thickness has regional brain specificity and if it is mediated by white matter hyperintensities (WMH). A total of 512 participants were included in this study. CAC scores were assessed by multi-detector computed tomography. Cortical thickness was measured using a surface-based method. Linear mixed models were used to assess the association between CAC scores and cortical thickness. In fully adjusted models, increased CAC scores were associated with cortical thinning across several brain regions, which generally overlapped with the distribution of default mode network. The association between CAC scores and cortical thickness was significantly stronger in participants with moderate or severe WMH compared to those with none or mild WMH, even though CAC scores were not associated with WMH. In cognitively normal adults, CAC was associated with cortical thinning in areas related to cognitive function. This association was evident after adjusting for multiple coronary artery disease risk factors and for WMH, suggesting that CAC may be more closely related to Alzheimer’s Disease-type disease rather than to cerebral small vessel disease. PMID:27694965

  11. Neuron numbers in sensory cortices of five delphinids compared to a physeterid, the pygmy sperm whale.

    PubMed

    Poth, C; Fung, C; Güntürkün, O; Ridgway, S H; Oelschläger, H H A

    2005-09-15

    With its large mass and enormous gyrification, the neocortex of whales and dolphins has always been a challenge to neurobiologists. Here we analyse the relationship between neuron number per cortical unit in three different sensory areas and brain mass in six different toothed whale species, five delphinids and one physeterid. Cortex samples, including primary cortical areas of the auditory, visual, and somatosensory systems were taken from both hemispheres of brains fixed in 10% buffered formalin. The samples were embedded in paraffin, sectioned at 25 microm thickness and stained with cresyl violet. Because cortical thickness varies among toothed whale species, cell counts were done in cortical units measuring 150mum in width, 25 microm in thickness, and extending from the pial surface to the white matter. By arranging the delphinid brains according to their total mass, 834-6052 g, we found decreasing neuron numbers in the investigated areas with increasing brain mass. The pigmy sperm whale (Kogia breviceps), a physeterid with an adult brain weight of 1000 g had a distinctly lower neuron number per cortical unit. As had been expected, an increase in adult brain weight in delphinid cetaceans (family Delphinidae) is not correlated with an increase in neuron number per cortical unit.

  12. A general framework for dynamic cortical function: the function-through-biased-oscillations (FBO) hypothesis

    PubMed Central

    Schalk, Gerwin

    2015-01-01

    A central goal of neuroscience is to determine how the brain's relatively static anatomy can support dynamic cortical function, i.e., cortical function that varies according to task demands. In pursuit of this goal, scientists have produced a large number of experimental results and established influential conceptual frameworks, in particular communication-through-coherence (CTC) and gating-by-inhibition (GBI), but these data and frameworks have not provided a parsimonious view of the principles that underlie cortical function. Here I synthesize these existing experimental results and the CTC and GBI frameworks, and propose the function-through-biased-oscillations (FBO) hypothesis as a model to understand dynamic cortical function. The FBO hypothesis suggests that oscillatory voltage amplitude is the principal measurement that directly reflects cortical excitability, that asymmetries in voltage amplitude explain a range of brain signal phenomena, and that predictive variations in such asymmetric oscillations provide a simple and general model for information routing that can help to explain dynamic cortical function. PMID:26136676

  13. Reassessing cortical reorganization in the primary sensorimotor cortex following arm amputation

    PubMed Central

    Scholz, Jan; Henderson Slater, David; Johansen-Berg, Heidi; Tracey, Irene

    2015-01-01

    The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, despite its growing popularity, the evidence to support the maladaptive plasticity theory is largely based on correlations between pain ratings and oftentimes crude measurements of cortical reorganization, with little consideration of potential contributions of other clinical factors, such as adaptive behaviour, in driving the identified brain plasticity. Here, we used a physiologically meaningful measurement of cortical reorganization to reassess its relationship to phantom pain in upper limb amputees. We identified small yet consistent shifts in lip representation contralateral to the missing hand towards, but not invading, the hand area. However, we were unable to identify any statistical relationship between cortical reorganization and phantom sensations or pain either with this measurement or with the traditional Euclidian distance measurement. Instead, we demonstrate that other factors may contribute to the observed remapping. Further research that reassesses more broadly the relationship between cortical reorganization and chronic pain is warranted. PMID:26072517

  14. Adolescent brain maturation and cortical folding: evidence for reductions in gyrification.

    PubMed

    Klein, Daniel; Rotarska-Jagiela, Anna; Genc, Erhan; Sritharan, Sharmili; Mohr, Harald; Roux, Frederic; Han, Cheol E; Kaiser, Marcus; Singer, Wolf; Uhlhaas, Peter J

    2014-01-01

    Evidence from anatomical and functional imaging studies have highlighted major modifications of cortical circuits during adolescence. These include reductions of gray matter (GM), increases in the myelination of cortico-cortical connections and changes in the architecture of large-scale cortical networks. It is currently unclear, however, how the ongoing developmental processes impact upon the folding of the cerebral cortex and how changes in gyrification relate to maturation of GM/WM-volume, thickness and surface area. In the current study, we acquired high-resolution (3 Tesla) magnetic resonance imaging (MRI) data from 79 healthy subjects (34 males and 45 females) between the ages of 12 and 23 years and performed whole brain analysis of cortical folding patterns with the gyrification index (GI). In addition to GI-values, we obtained estimates of cortical thickness, surface area, GM and white matter (WM) volume which permitted correlations with changes in gyrification. Our data show pronounced and widespread reductions in GI-values during adolescence in several cortical regions which include precentral, temporal and frontal areas. Decreases in gyrification overlap only partially with changes in the thickness, volume and surface of GM and were characterized overall by a linear developmental trajectory. Our data suggest that the observed reductions in GI-values represent an additional, important modification of the cerebral cortex during late brain maturation which may be related to cognitive development.

  15. Cortical bone development under the growth plate is regulated by mechanical load transfer.

    PubMed

    Tanck, E; Hannink, G; Ruimerman, R; Buma, P; Burger, E H; Huiskes, R

    2006-01-01

    Longitudinal growth of long bones takes place at the growth plates. The growth plate produces new bone trabeculae, which are later resorbed or merged into the cortical shell. This process implies transition of trabecular metaphyseal sections into diaphyseal sections. We hypothesize that the development of cortical bone is governed by mechanical stimuli. We also hypothesize that trabecular and cortical bone share the same regulatory mechanisms for adaptation to mechanical loads. To test these hypotheses, we monitored the development of the tibial cortex in growing pigs, using micro-computer tomography and histology. We then tested the concept that regulatory mechanisms for trabecular bone adaptation can also explain cortical bone development using our mechanical stimulation theory, which could explain trabecular bone (re)modelling. The main results showed that, from the growth plate towards the diaphysis, the pores of the trabecular structure were gradually filled in with bone, which resulted in increased density and cortical bone. The computer model largely predicted this morphological development. We conclude that merging of metaphyseal trabeculae into cortex is likely to be governed by mechanical stimuli. Furthermore, cortex development of growing long bones can be explained as a form of trabecular bone adaptation, without the need for different regulatory mechanisms for cortical and trabecular bone.

  16. Dosage effects of BDNF Val66Met polymorphism on cortical surface area and functional connectivity.

    PubMed

    Wang, Chao; Zhang, Yuanchao; Liu, Bing; Long, Haixia; Yu, Chunshui; Jiang, Tianzi

    2014-02-12

    The single nucleotide polymorphism (SNP) that leads to a valine-to-methionine substitution at codon 66 (Val66Met) in BDNF is correlated with differences in cognitive and memory functions, as well as with several neurological and psychiatric disorders. MRI studies have already shown that this genetic variant contributes to changes in cortical thickness and volume, but whether the Val66Met polymorphism affects the cortical surface area of healthy subjects remains unclear. Here, we used multimodal MRI to study whether this polymorphism would affect the cortical morphology and resting-state functional connectivity of a large sample of healthy Han Chinese human subjects. An SNP-wise general linear model analysis revealed a "dosage effect" of the Met allele, specifically a stepwise increase in cortical surface area of the right anterior insular cortex with increasing numbers of the Met allele. Moreover, we found enhanced functional connectivity between the anterior insular and the dorsolateral prefrontal cortices that was linked with the dosage of the Met allele. In conclusion, these data demonstrated a "dosage effect" of BDNF Val66Met on normal cortical structure and function, suggesting a new path for exploring the mechanisms underlying the effects of genotype on cognition.

  17. Multimodal analysis of cortical chemoarchitecture and macroscale fMRI resting‐state functional connectivity

    PubMed Central

    Scholtens, Lianne H.; Turk, Elise; Mantini, Dante; Vanduffel, Wim; Feldman Barrett, Lisa

    2016-01-01

    Abstract The cerebral cortex is well known to display a large variation in excitatory and inhibitory chemoarchitecture, but the effect of this variation on global scale functional neural communication and synchronization patterns remains less well understood. Here, we provide evidence of the chemoarchitecture of cortical regions to be associated with large‐scale region‐to‐region resting‐state functional connectivity. We assessed the excitatory versus inhibitory chemoarchitecture of cortical areas as an ExIn ratio between receptor density mappings of excitatory (AMPA, M1) and inhibitory (GABAA, M2) receptors, computed on the basis of data collated from pioneering studies of autoradiography mappings as present in literature of the human (2 datasets) and macaque (1 dataset) cortex. Cortical variation in ExIn ratio significantly correlated with total level of functional connectivity as derived from resting‐state functional connectivity recordings of cortical areas across all three datasets (human I: P = 0.0004; human II: P = 0.0008; macaque: P = 0.0007), suggesting cortical areas with an overall more excitatory character to show higher levels of intrinsic functional connectivity during resting‐state. Our findings are indicative of the microscale chemoarchitecture of cortical regions to be related to resting‐state fMRI connectivity patterns at the global system's level of connectome organization. Hum Brain Mapp 37:3103–3113, 2016. © 2016 Wiley Periodicals, Inc. PMID:27207489

  18. Comparative characterization of the basic forebrain cortical zones in Emys orbicularis (Linnaeus) and Testudo horsfieldi (Gray).

    PubMed

    Davydova, T V; Goncharova, N V

    1979-01-01

    The neuronal and synaptic organization of forebrain basic cortical zones in Testudo horsfieldi and Emys orbicularis and their dendritic spines have been studied using Nissle, Golgi and electron microscopic methods. It has been shown by comparison of the results that the two spicies have marked differences in the structural organization of the forebrain cortical zones. The cortical formation in Testudo horsfieldi is different from that of Emys orbicularis in a greater diversity of neuronal types, smaller size of neurons, smaller cell density in each cortical zones, the presence of horizontal dendritic terminals in dorsomedial dorsal cortex, the absence of the large neurons in dorsomedial medial cortex, ect. Moreover, in both species the dorsomedial dorsal cortex in comparison with medial and lateral cortex is characterized by a marked complexity of the structural organization (diverse neuronal composition, the presence of the stellate cells, the highest cell density, the smallest neuronal size). The investigation of spines in the different dendritic levels (proximal, middle and distal) of neurons in three cortical basic zones has been shown that in both species it has been observed the tendency to increasing of the spine density from proximal to distal part of dendrite. at all dendritic levels noninvaginated forms of spines predominated. Invaginated spines were recorded at the proximal and middle levels of dendrites and contain more organelles and inclusions than noninvaginated spines. In Testudo horsfieldi and Emys orbicularis differences of spine thin structure and spine density in the cortical basic zones were revealed. Moreover, in both species the spines of dorsomedial dorsal cortex were more numerous, more variable in shape, more abundant in organelles. It was there that a bush-like distribution of spines was found which in evidently a special form of synaptic organization of cortical neurons. The above features of this cortical zone indicates a higher degree

  19. Sparse cortical current density imaging in motor potentials induced by finger movement

    NASA Astrophysics Data System (ADS)

    Ding, Lei; Ni, Ying; Sweeney, John; He, Bin

    2011-06-01

    Predominant components in electro- or magneto-encephalography (EEG/MEG) are scalp projections of synchronized neuronal electrical activity distributed over cortical structures. Reconstruction of cortical sources underlying EEG/MEG can thus be achieved with the use of the cortical current density (CCD) model. We have developed a sparse electromagnetic source imaging method based on the CCD model, named as the variation-based cortical current density (VB-SCCD) algorithm, and have shown that it has much enhanced performance in reconstructing extended cortical sources in simulations (Ding 2009 Phys. Med. Biol. 54 2683-97). The present study aims to evaluate the performance of VB-SCCD, for the first time, using experimental data obtained from six participants. The results indicate that the VB-SCCD algorithm is able to successfully reveal spatially distributed cortical sources behind motor potentials induced by visually cued repetitive finger movements, and their dynamic patterns, with millisecond resolution. These findings of motor sources and cortical systems are supported by the physiological knowledge of motor control and evidence from various neuroimaging studies with similar experiments. Furthermore, our present results indicate the improvement of cortical source resolvability of VB-SCCD, as compared with two other classical algorithms. The proposed solver embedded in VB-SCCD is able to handle large-scale computational problems, which makes the use of high-density CCD models possible and, thus, reduces model misspecifications. The present results suggest that VB-SCCD provides high resolution source reconstruction capability and is a promising tool for studying complicated dynamic systems of brain activity for basic neuroscience and clinical neuropsychiatric research.

  20. Increased Testosterone Decreases Medial Cortical Volume and Neurogenesis in Territorial Side-Blotched Lizards (Uta stansburiana).

    PubMed

    LaDage, Lara D; Roth, Timothy C; Downs, Cynthia J; Sinervo, Barry; Pravosudov, Vladimir V

    2017-01-01

    Variation in an animal's spatial environment can induce variation in the hippocampus, an area of the brain involved in spatial cognitive processing. Specifically, increased spatial area use is correlated with increased hippocampal attributes, such as volume and neurogenesis. In the side-blotched lizard (Uta stansburiana), males demonstrate alternative reproductive tactics and are either territorial-defending large, clearly defined spatial boundaries-or non-territorial-traversing home ranges that are smaller than the territorial males' territories. Our previous work demonstrated cortical volume (reptilian hippocampal homolog) correlates with these spatial niches. We found that territorial holders have larger medial cortices than non-territory holders, yet these differences in the neural architecture demonstrated some degree of plasticity as well. Although we have demonstrated a link among territoriality, spatial use, and brain plasticity, the mechanisms that underlie this relationship are unclear. Previous studies found that higher testosterone levels can induce increased use of the spatial area and can cause an upregulation in hippocampal attributes. Thus, testosterone may be the mechanistic link between spatial area use and the brain. What remains unclear, however, is if testosterone can affect the cortices independent of spatial experiences and whether testosterone differentially interacts with territorial status to produce the resultant cortical phenotype. In this study, we compared neurogenesis as measured by the total number of doublecortin-positive cells and cortical volume between territorial and non-territorial males supplemented with testosterone. We found no significant differences in the number of doublecortin-positive cells or cortical volume among control territorial, control non-territorial, and testosterone-supplemented non-territorial males, while testosterone-supplemented territorial males had smaller medial cortices containing fewer doublecortin

  1. Increased Testosterone Decreases Medial Cortical Volume and Neurogenesis in Territorial Side-Blotched Lizards (Uta stansburiana)

    PubMed Central

    LaDage, Lara D.; Roth, Timothy C.; Downs, Cynthia J.; Sinervo, Barry; Pravosudov, Vladimir V.

    2017-01-01

    Variation in an animal's spatial environment can induce variation in the hippocampus, an area of the brain involved in spatial cognitive processing. Specifically, increased spatial area use is correlated with increased hippocampal attributes, such as volume and neurogenesis. In the side-blotched lizard (Uta stansburiana), males demonstrate alternative reproductive tactics and are either territorial—defending large, clearly defined spatial boundaries—or non-territorial—traversing home ranges that are smaller than the territorial males' territories. Our previous work demonstrated cortical volume (reptilian hippocampal homolog) correlates with these spatial niches. We found that territorial holders have larger medial cortices than non-territory holders, yet these differences in the neural architecture demonstrated some degree of plasticity as well. Although we have demonstrated a link among territoriality, spatial use, and brain plasticity, the mechanisms that underlie this relationship are unclear. Previous studies found that higher testosterone levels can induce increased use of the spatial area and can cause an upregulation in hippocampal attributes. Thus, testosterone may be the mechanistic link between spatial area use and the brain. What remains unclear, however, is if testosterone can affect the cortices independent of spatial experiences and whether testosterone differentially interacts with territorial status to produce the resultant cortical phenotype. In this study, we compared neurogenesis as measured by the total number of doublecortin-positive cells and cortical volume between territorial and non-territorial males supplemented with testosterone. We found no significant differences in the number of doublecortin-positive cells or cortical volume among control territorial, control non-territorial, and testosterone-supplemented non-territorial males, while testosterone-supplemented territorial males had smaller medial cortices containing fewer

  2. Dynamic cortical lateralization during olfactory discrimination learning

    PubMed Central

    Cohen, Yaniv; Putrino, David; Wilson, Donald A

    2015-01-01

    Key points Odour discrimination and memory involve changes in the primary olfactory (piriform) cortex. The results obtained in the present study suggest that there is an asymmetry in piriform cortical change, with learning-related changes in cortical oscillations emerging with different time courses over the course of multiday training in the left and right piriform cortices in rats. There is an initial decrease in coherence between the left and right piriform cortices during the early stages of the odour discrimination task, which recovers as the animals approach criterion performance. This decreased coherence is expressed when the animals are performing the task relative to when they are in their home cage. The results suggest a transient cortical asymmetry during learning and raise new questions about the functions and mechanisms of cerebral lateralization. Abstract Bilateral cortical circuits are not necessarily symmetrical. Asymmetry, or cerebral lateralization, allows functional specialization of bilateral brain regions and has been described in humans for such diverse functions as perception, memory and emotion. There is also evidence for asymmetry in the human olfactory system, although evidence in non-human animal models is lacking. In the present study, we took advantage of the known changes in olfactory cortical local field potentials that occur over the course of odour discrimination training to test for functional asymmetry in piriform cortical activity during learning. Both right and left piriform cortex local field potential activities were recorded. The results obtained demonstrate a robust interhemispheric asymmetry in anterior piriform cortex activity that emerges during specific stages of odour discrimination learning, with a transient bias toward the left hemisphere. This asymmetry is not apparent during error trials. Furthermore, functional connectivity (coherence) between the bilateral anterior piriform cortices is learning- and context

  3. Cavitary osteomyelitis treated by fragmentary cortical bone transportation.

    PubMed

    Aronson, J

    1992-07-01

    Fragmentary cortical bone transportation can be used to fill large gaps in chronic cavitary osteomyelitis when standard techniques have failed. A low-energy corticotomy can create a loose fragment of cortex with periosteal attachments and surface blood supply still intact. This "vital" fragment can be gradually pulled across a defect within a bone to restore the integrity of the bone segment by distraction osteogenesis. The biologic principles for successful distraction osteogenesis by this innovative technique are illustrated in a 41-year-old man with chronic cavitary (150 cc) (four years) osteomyelitis refractory to multiple debridements, Papineau grafting, gentamicin beads, and tricalcium phosphate.

  4. Coherent delta-band oscillations between cortical areas correlate with decision making

    PubMed Central

    Nácher, Verónica; Ledberg, Anders; Deco, Gustavo; Romo, Ranulfo

    2013-01-01

    Coherent oscillations in the theta-to-gamma frequency range have been proposed as a mechanism that coordinates neural activity in large-scale cortical networks in sensory, motor, and cognitive tasks. Whether this mechanism also involves coherent oscillations at delta frequencies (1–4 Hz) is not known. Rather, delta oscillations have been associated with slow-wave sleep. Here, we show coherent oscillations in the delta frequency band between parietal and frontal cortices during the decision-making component of a somatosensory discrimination task. Importantly, the magnitude of this delta-band coherence is modulated by the different decision alternatives. Furthermore, during control conditions not requiring decision making, delta-band coherences are typically much reduced. Our work indicates an important role for synchronous activity in the delta frequency band when large-scale, distant cortical networks coordinate their neural activity during decision making. PMID:23980180

  5. Spatial Patterns, Longitudinal Development, and Hemispheric Asymmetries of Cortical Thickness in Infants from Birth to 2 Years of Age.

    PubMed

    Li, Gang; Lin, Weili; Gilmore, John H; Shen, Dinggang

    2015-06-17

    Cortical thickness (CT) is related to normal development and neurodevelopmental disorders. It remains largely unclear how the characteristic patterns of CT evolve in the first 2 years. In this paper, we systematically characterized for the first time the detailed vertex-wise patterns of spatial distribution, longitudinal development, and hemispheric asymmetries of CT at 0, 1, and 2 years of age, via surface-based analysis of 219 longitudinal magnetic resonance images from 73 infants. Despite the dynamic increase of CT in the first year and the little change of CT in the second year, we found that the overall spatial distribution of thin and thick cortices was largely present at birth, and evolved only modestly during the first 2 years. Specifically, the precentral gyrus, postcentral gyrus, occipital cortex, and superior parietal region had thin cortices, whereas the prefrontal, lateral temporal, insula, and inferior parietal regions had thick cortices. We revealed that in the first year thin cortices exhibited low growth rates of CT, whereas thick cortices exhibited high growth rates. We also found that gyri were thicker than sulci, and that the anterior bank of the central sulcus was thicker than the posterior bank. Moreover, we showed rightward hemispheric asymmetries of CT in the lateral temporal and posterior insula regions at birth, which shrank gradually in the first 2 years, and also leftward asymmetries in the medial prefrontal, paracentral, and anterior cingulate cortices, which expanded substantially during this period. This study provides the first comprehensive picture of early patterns and evolution of CT during infancy.

  6. Osmosis in Cortical Collecting Tubules

    PubMed Central

    Schafer, James A.; Troutman, Susan L.; Andreoli, Thomas E.

    1974-01-01

    The present experiments were designed to evaluate the effects of varying the osmolality of luminal solutions on the antidiuretic hormone (ADH)-independent water and solute permeability properties of isolated rabbit cortical collecting tubules. In the absence of ADH, the osmotic water permeability coefficient (cm s–1) Pfl→b, computed from volume flows from hypotonic lumen to isotonic bath, was 20 ± 4 x 10–4 (SEM); the value of Pfb→l in the absence of ADH, computed from volume flows from isotonic bath to hypertonic lumen, was 88 ± 15 x 10–4 cm s–1. We also measured apparent urea permeability coefficients (cm s–1) from 14C-urea fluxes from lumen to bath (PDDureal→b) and from bath to lumen (PDDureab→l). For hypotonic luminal solutions and isotonic bathing solutions, PDDureal→b was 0.045 ± 0.004 x 10–4 and was unaffected by ADH. The ADH-independent values of PDDureal→b and Pureab→l were, respectively, 0.216 ± 0.022 x 10–4 cm s–1 and 0.033 ± 0.002 x 10–4 cm s–1 for isotonic bathing solutions and luminal solutions made hypertonic with urea, i.e., there was an absolute increase in urea permeability and asymmetry of urea fluxes. Significantly, PDDureal→b did not rise when luminal hypertonicity was produced by sucrose; and, bathing fluid hypertonicity did not alter tubular permeability to water or to urea. We interpret these data to indicate that luminal hypertonicity increased the leakiness of tight junctions to water and urea but not sucrose. Since the value of Pfb→l in the absence of ADH, when tight junctions were open to urea, was approximately half of the value of Pfl→b in the presence of ADH, when tight junctions were closed to urea, we conclude that tight junctions are negligible paracellular shunts for lumen to bath osmosis with ADH. These findings, together with those in the preceding paper, are discussed in terms of a solubility-diffusion model for water permeation in which ADH increases water solubility in luminal

  7. RGMa regulates cortical interneuron migration and differentiation.

    PubMed

    O'Leary, Conor; Cole, Stacey J; Langford, Michael; Hewage, Jayani; White, Amanda; Cooper, Helen M

    2013-01-01

    The etiology of neuropsychiatric disorders, including schizophrenia and autism, has been linked to a failure to establish the intricate neural network comprising excitatory pyramidal and inhibitory interneurons during neocortex development. A large proportion of cortical inhibitory interneurons originate in the medial ganglionic eminence (MGE) of the ventral telencephalon and then migrate through the ventral subventricular zone, across the corticostriatal junction, into the embryonic cortex. Successful navigation of newborn interneurons through the complex environment of the ventral telencephalon is governed by spatiotemporally restricted deployment of both chemorepulsive and chemoattractive guidance cues which work in concert to create a migratory corridor. Despite the expanding list of interneuron guidance cues, cues responsible for preventing interneurons from re-entering the ventricular zone of the ganglionic eminences have not been well characterized. Here we provide evidence that the chemorepulsive axon guidance cue, RGMa (Repulsive Guidance Molecule a), may fulfill this function. The ventricular zone restricted expression of RGMa in the ganglionic eminences and the presence of its receptor, Neogenin, in the ventricular zone and on newborn and maturing MGE-derived interneurons implicates RGMa-Neogenin interactions in interneuron differentiation and migration. Using an in vitro approach, we show that RGMa promotes interneuron differentiation by potentiating neurite outgrowth. In addition, using in vitro explant and migration assays, we provide evidence that RGMa is a repulsive guidance cue for newborn interneurons migrating out of the ganglionic eminence ventricular zone. Intriguingly, the alternative Neogenin ligand, Netrin-1, had no effect on migration. However, we observed complete abrogation of RGMa-induced chemorepulsion when newborn interneurons were simultaneously exposed to RGMa and Netrin-1 gradients, suggesting a novel mechanism for the tight

  8. Simulating Cortical Feedback Modulation as Changes in Excitation and Inhibition in a Cortical Circuit Model

    PubMed Central

    Murray, John D.; McCormick, David A.

    2016-01-01

    Abstract Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced sensory representations. However, the cellular mechanisms underlying these effects are currently unknown. In this study we use a simplified neural circuit model, which includes two recurrent excitatory populations and global inhibition, to simulate cortical modulation. First, we demonstrate how changes in the strengths of excitation and inhibition alter the input–output processing responses of our model. Second, we compare these responses with experimental findings from cortical feedback stimulation. Our analyses predict that enhanced inhibition underlies the changes in spontaneous and sensory evoked activity observed experimentally. More generally, these analyses provide a framework for relating cellular and synaptic properties to emergent circuit function and dynamic modulation. PMID:27595137

  9. Intralaminar and medial thalamic influence on cortical synchrony, information transmission and cognition

    PubMed Central

    Saalmann, Yuri B.

    2014-01-01

    The intralaminar and medial thalamic nuclei are part of the higher-order thalamus, which receives little sensory input, and instead forms extensive cortico-thalamo-cortical pathways. The large mediodorsal thalamic nucleus predominantly connects with the prefrontal cortex, the adjacent intralaminar nuclei connect with fronto-parietal cortex, and the midline thalamic nuclei connect with medial prefrontal cortex and medial temporal lobe. Taking into account this connectivity pattern, it is not surprising that the intralaminar and medial thalamus has been implicated in a variety of cognitive functions, including memory processing, attention and orienting, as well as reward-based behavior. This review addresses how the intralaminar and medial thalamus may regulate information transmission in cortical circuits. A key neural mechanism may involve intralaminar and medial thalamic neurons modulating the degree of synchrony between different groups of cortical neurons according to behavioral demands. Such a thalamic-mediated synchronization mechanism may give rise to large-scale integration of information across multiple cortical circuits, consequently influencing the level of arousal and consciousness. Overall, the growing evidence supports a general role for the higher-order thalamus in the control of cortical information transmission and cognitive processing. PMID:24847225

  10. Generation and Evaluation of a Cortical Area Parcellation from Resting-State Correlations

    PubMed Central

    Gordon, Evan M.; Laumann, Timothy O.; Adeyemo, Babatunde; Huckins, Jeremy F.; Kelley, William M.; Petersen, Steven E.

    2016-01-01

    The cortical surface is organized into a large number of cortical areas; however, these areas have not been comprehensively mapped in the human. Abrupt transitions in resting-state functional connectivity (RSFC) patterns can noninvasively identify locations of putative borders between cortical areas (RSFC-boundary mapping; Cohen et al. 2008). Here we describe a technique for using RSFC-boundary maps to define parcels that represent putative cortical areas. These parcels had highly homogenous RSFC patterns, indicating that they contained one unique RSFC signal; furthermore, the parcels were much more homogenous than a null model matched for parcel size when tested in two separate datasets. Several alternative parcellation schemes were tested this way, and no other parcellation was as homogenous as or had as large a difference compared with its null model. The boundary map-derived parcellation contained parcels that overlapped with architectonic mapping of areas 17, 2, 3, and 4. These parcels had a network structure similar to the known network structure of the brain, and their connectivity patterns were reliable across individual subjects. These observations suggest that RSFC-boundary map-derived parcels provide information about the location and extent of human cortical areas. A parcellation generated using this method is available at http://www.nil.wustl.edu/labs/petersen/Resources.html. PMID:25316338

  11. Generation and Evaluation of a Cortical Area Parcellation from Resting-State Correlations.

    PubMed

    Gordon, Evan M; Laumann, Timothy O; Adeyemo, Babatunde; Huckins, Jeremy F; Kelley, William M; Petersen, Steven E

    2016-01-01

    The cortical surface is organized into a large number of cortical areas; however, these areas have not been comprehensively mapped in the human. Abrupt transitions in resting-state functional connectivity (RSFC) patterns can noninvasively identify locations of putative borders between cortical areas (RSFC-boundary mapping; Cohen et al. 2008). Here we describe a technique for using RSFC-boundary maps to define parcels that represent putative cortical areas. These parcels had highly homogenous RSFC patterns, indicating that they contained one unique RSFC signal; furthermore, the parcels were much more homogenous than a null model matched for parcel size when tested in two separate datasets. Several alternative parcellation schemes were tested this way, and no other parcellation was as homogenous as or had as large a difference compared with its null model. The boundary map-derived parcellation contained parcels that overlapped with architectonic mapping of areas 17, 2, 3, and 4. These parcels had a network structure similar to the known network structure of the brain, and their connectivity patterns were reliable across individual subjects. These observations suggest that RSFC-boundary map-derived parcels provide information about the location and extent of human cortical areas. A parcellation generated using this method is available at http://www.nil.wustl.edu/labs/petersen/Resources.html.

  12. Surround suppression and sparse coding in visual and barrel cortices

    PubMed Central

    Sachdev, Robert N. S.; Krause, Matthew R.; Mazer, James A.

    2012-01-01

    During natural vision the entire retina is stimulated. Likewise, during natural tactile behaviors, spatially extensive regions of the somatosensory surface are co-activated. The large spatial extent of naturalistic stimulation means that surround suppression, a phenomenon whose neural mechanisms remain a matter of debate, must arise during natural behavior. To identify common neural motifs that might instantiate surround suppression across modalities, we review models of surround suppression and compare the evidence supporting the competing ideas that surround suppression has either cortical or sub-cortical origins in visual and barrel cortex. In the visual system there is general agreement lateral inhibitory mechanisms contribute to surround suppression, but little direct experimental evidence that intracortical inhibition plays a major role. Two intracellular recording studies of V1, one using naturalistic stimuli (Haider et al., 2010), the other sinusoidal gratings (Ozeki et al., 2009), sought to identify the causes of reduced activity in V1 with increasing stimulus size, a hallmark of surround suppression. The former attributed this effect to increased inhibition, the latter to largely balanced withdrawal of excitation and inhibition. In rodent primary somatosensory barrel cortex, multi-whisker responses are generally weaker than single whisker responses, suggesting multi-whisker stimulation engages similar surround suppressive mechanisms. The origins of suppression in S1 remain elusive: studies have implicated brainstem lateral/internuclear interactions and both thalamic and cortical inhibition. Although the anatomical organization and instantiation of surround suppression in the visual and somatosensory systems differ, we consider the idea that one common function of surround suppression, in both modalities, is to remove the statistical redundancies associated with natural stimuli by increasing the sparseness or selectivity of sensory responses. PMID:22783169

  13. Cortical hierarchy governs rat claustrocortical circuit organization.

    PubMed

    White, Michael G; Cody, Patrick A; Bubser, Michael; Wang, Hui-Dong; Deutch, Ariel Y; Mathur, Brian N

    2017-04-15

    The claustrum is a telencephalic gray matter structure with various proposed functions, including sensory integration and attentional allocation. Underlying these concepts is the reciprocal connectivity of the claustrum with most, if not all, areas of the cortex. What remains to be elucidated to inform functional hypotheses further is whether a pattern exists in the strength of connectivity between a given cortical area and the claustrum. To this end, we performed a series of retrograde neuronal tract tracer injections into rat cortical areas along the cortical processing hierarchy, from primary sensory and motor to frontal cortices. We observed that the number of claustrocortical projections increased as a function of processing hierarchy; claustrum neurons projecting to primary sensory cortices were scant and restricted in distribution across the claustrum, whereas neurons projecting to the cingulate cortex were densely packed and more evenly distributed throughout the claustrum. This connectivity pattern suggests that the claustrum may preferentially subserve executive functions orchestrated by the cingulate cortex. J. Comp. Neurol. 525:1347-1362, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. Cortical Gyrification Patterns Associated with Trait Anxiety

    PubMed Central

    Miskovich, Tara A.; Pedersen, Walker S.; Belleau, Emily L.; Shollenbarger, Skyler; Lisdahl, Krista M.; Larson, Christine L.

    2016-01-01

    Dispositional anxiety is a stable personality trait that is a key risk factor for internalizing disorders, and understanding the neural correlates of trait anxiety may help us better understand the development of these disorders. Abnormal cortical folding is thought to reflect differences in cortical connectivity occurring during brain development. Therefore, assessing gyrification may advance understanding of cortical development and organization associated with trait anxiety. Previous literature has revealed structural abnormalities in trait anxiety and related disorders, but no study to our knowledge has examined gyrification in trait anxiety. We utilized a relatively novel measure, the local gyrification index (LGI), to explore differences in gyrification as a function of trait anxiety. We obtained structural MRI scans using a 3T magnetic resonance scanner on 113 young adults. Results indicated a negative correlation between trait anxiety and LGI in the left superior parietal cortex, specifically the precuneus, reflecting less cortical complexity among those high on trait anxiety. Our findings suggest that aberrations in cortical gyrification in a key region of the default mode network is a correlate of trait anxiety and may reflect disrupted local parietal connectivity. PMID:26872350

  15. Automatic parcellation of longitudinal cortical surfaces

    NASA Astrophysics Data System (ADS)

    Alassaf, Manal H.; Hahn, James K.

    2015-03-01

    We present a novel automatic method to parcellate the cortical surfaces of the neonatal brain longitudinal atlas at different stages of development. A labeled brain atlas of newborn at 41 weeks gestational age (GA) is used to propagate labels of anatomical regions of interest to an unlabeled spatio-temporal atlas, which provides a dynamic model of brain development at each week between 28-44 GA weeks. First, labels from the cortical volume of the labeled newborn brain are propagated to an age-matched cortical surface from the spatio-temporal atlas. Then, labels are propagated across the cortical surfaces of each week of the spatio-temporal atlas by registering successive cortical surfaces using a novel approach and an energy optimization function. This procedure incorporates local and global, spatial and temporal information when assigning the labels to each surface. The result is a complete parcellation of 17 neonatal brain surfaces of the spatio-temporal atlas with similar points per labels distributions across weeks.

  16. Micromechanics of osteonal cortical bone fracture.

    PubMed

    Guo, X E; Liang, L C; Goldstein, S A

    1998-02-01

    Microcracks have been associated with age-related bone tissue fragility and fractures. The objective of this study was to develop a simple osteonal cortical bone model and apply linear elastic fracture mechanics theory to understand the micromechanics of the fracture process in osteonal cortical bone and its dependence on material properties. The linear fracture mechanics of our composite model of cortical bone, consisting of an osteon and interstitial bone tissue, was characterized in terms of a stress intensity factor (SIF) near the tip of a microcrack. The interaction between a microcrack and an osteon was studied for different types of osteons and various spacing between the crack and the osteon. The results of the analysis indicate that the fracture mechanics of osteonal cortical bone is dominated by the modulus ratio between the osteon and interstitial bone tissue: A soft osteon promotes microcrack propagation toward the osteon (and cement line) while a stiff one repels the microcrack from the osteon (and cement line). These findings suggest that newly formed, low-stiffness osteons may toughen cortical bone tissue by promoting crack propagation toward osteons. A relatively accurate empirical formula also was obtained to provide an easy estimation of the influence of osteons on the stress intensity factor.

  17. Symmetry breaking in reconstituted actin cortices

    PubMed Central

    Abu Shah, Enas; Keren, Kinneret

    2014-01-01

    The actin cortex plays a pivotal role in cell division, in generating and maintaining cell polarity and in motility. In all these contexts, the cortical network has to break symmetry to generate polar cytoskeletal dynamics. Despite extensive research, the mechanisms responsible for regulating cortical dynamics in vivo and inducing symmetry breaking are still unclear. Here we introduce a reconstituted system that self-organizes into dynamic actin cortices at the inner interface of water-in-oil emulsions. This artificial system undergoes spontaneous symmetry breaking, driven by myosin-induced cortical actin flows, which appears remarkably similar to the initial polarization of the embryo in many species. Our in vitro model system recapitulates the rich dynamics of actin cortices in vivo, revealing the basic biophysical and biochemical requirements for cortex formation and symmetry breaking. Moreover, this synthetic system paves the way for further exploration of artificial cells towards the realization of minimal model systems that can move and divide. DOI: http://dx.doi.org/10.7554/eLife.01433.001 PMID:24843007

  18. Role of cortical bone in hip fracture.

    PubMed

    Reeve, Jonathan

    2017-01-01

    In this review, I consider the varied mechanisms in cortical bone that help preserve its integrity and how they deteriorate with aging. Aging affects cortical bone in two ways: extrinsically through its effects on the individual that modify its mechanical loading experience and 'milieu interieur'; and intrinsically through the prolonged cycle of remodelling and renewal extending to an estimated 20 years in the proximal femur. Healthy femoral cortex incorporates multiple mechanisms that help prevent fracture. These have been described at multiple length scales from the individual bone mineral crystal to the scale of the femur itself and appear to operate hierarchically. Each cortical bone fracture begins as a sub-microscopic crack that enlarges under mechanical load, for example, that imposed by a fall. In these conditions, a crack will enlarge explosively unless the cortical bone is intrinsically tough (the opposite of brittle). Toughness leads to microscopic crack deflection and bridging and may be increased by adequate regulation of both mineral crystal size and the heterogeneity of mineral and matrix phases. The role of osteocytes in optimising toughness is beginning to be worked out; but many osteocytes die in situ without triggering bone renewal over a 20-year cycle, with potential for increasing brittleness. Furthermore, the superolateral cortex of the proximal femur thins progressively during life, so increasing the risk of buckling during a fall. Besides preserving or increasing hip BMD, pharmaceutical treatments have class-specific effects on the toughness of cortical bone, although dietary and exercise-based interventions show early promise.

  19. Decreased prefrontal cortical dopamine transmission in alcoholism.

    PubMed

    Narendran, Rajesh; Mason, Neale Scott; Paris, Jennifer; Himes, Michael L; Douaihy, Antoine B; Frankle, W Gordon

    2014-08-01

    Basic studies have demonstrated that optimal levels of prefrontal cortical dopamine are critical to various executive functions such as working memory, attention, inhibitory control, and risk/reward decisions, all of which are impaired in addictive disorders such as alcoholism. Based on this and imaging studies of alcoholism that have demonstrated less dopamine in the striatum, the authors hypothesized decreased dopamine transmission in the prefrontal cortex in persons with alcohol dependence. To test this hypothesis, amphetamine and [11C]FLB 457 positron emission tomography were used to measure cortical dopamine transmission in 21 recently abstinent persons with alcohol dependence and 21 matched healthy comparison subjects. [11C]FLB 457 binding potential, specific compared to nondisplaceable uptake (BPND), was measured in subjects with kinetic analysis using the arterial input function both before and after 0.5 mg kg-1 of d-amphetamine. Amphetamine-induced displacement of [11C]FLB 457 binding potential (ΔBPND) was significantly smaller in the cortical regions in the alcohol-dependent group compared with the healthy comparison group. Cortical regions that demonstrated lower dopamine transmission in the alcohol-dependent group included the dorsolateral prefrontal cortex, medial prefrontal cortex, orbital frontal cortex, temporal cortex, and medial temporal lobe. The results of this study, for the first time, unambiguously demonstrate decreased dopamine transmission in the cortex in alcoholism. Further research is necessary to understand the clinical relevance of decreased cortical dopamine as to whether it is related to impaired executive function, relapse, and outcome in alcoholism.

  20. Altered cortical excitability in anorexia nervosa.

    PubMed

    Khedr, E M; El Fetoh, N A; El Bieh, E; Ali, A M; Karim, A A

    2014-09-01

    Recent EEG and positron emission tomography (PET) studies have reported hyperactivation of the right hemisphere in anorexia nervosa (AN). The aim of the present study was to test this notion by examining cortical excitability in subjects with AN using transcranial magnetic stimulation (TMS). We investigated thirteen patients meeting the DSM IV diagnostic criteria for AN and 14 controls age and sex matched. Each subject was assessed clinically using the Eating Disorder Inventory (EDI), the Eating Attitude Test (EAT) and Beck's Depression Inventory (BDI-II). TMS measures involved resting and active motor thresholds (RMT, AMT) as well as motor evoked potentials (MEP), cortical silent period duration (CSP), transcallosal inhibition (TCI), and short latency intracortical inhibition (SICI) of the first dorsal interosseous muscle (FDI) were assessed. Cortical esophageal MEP latencies (CL) were also recorded. The RMT and MEP onset latency of the FDI and the esophagus as well as duration of the TCI were significantly reduced in anorexic patients compared to the control group. There were no significant differences neither in AMT nor CSP between patients and controls. Moreover, we found significant negative correlations between the EAT scores and RMT, and TCI duration. Although anorexic patients had significantly higher BDI score, there was no correlation between it and cortical excitability. Anorexic individuals are characterized by pathologically increased motor and esophageal cortical excitability that significantly correlates with clinical symptoms of anorexia nervosa. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  1. Neurodynamics of somatosensory cortices studied by magnetoencephelography.

    PubMed

    Kishida, Kuniharu

    2013-09-01

    From the viewpoint of statistical inverse problems, identification of transfer functions in feedback models is applied for neurodynamics of somatosensory cortices, and brain communication among active regions can be expressed in terms of transfer functions. However, brain activities have been investigated mainly by averaged waveforms in the conventional magnetoencephalography analysis, and thus brain communication among active regions has not yet been identified. It is shown that brain communication among two more than three brain regions is determined, when fluctuations related to concatenate averaged waveforms can be obtained by using a suitable blind source separation method. In blind identification of feedback model, some transfer functions or their impulse responses between output variables of current dipoles corresponding to active regions are identified from reconstructed time series data of fluctuations by the method of inverse problem. Neurodynamics of somatosensory cortices in 5 Hz median nerve stimuli can be shown by cerebral communication among active regions of somatosensory cortices in terms of impulse responses of feedback model.

  2. Decision by division: making cortical maps

    PubMed Central

    Rakic, Pasko; Ayoub, Albert E.; Breunig, Joshua J.; Dominguez, Martin H.

    2013-01-01

    In the past three decades, mounting evidence has revealed that specification of the basic cortical neuronal classes starts at the time of their final mitotic divisions in the embryonic proliferative zones. This early cell determination continues during the migration of the newborn neurons across the widening cerebral wall, and it is in the cortical plate that they attain their final positions and establish species-specific cytoarchitectonic areas. Here, the development and evolutionary expansion of the neocortex is viewed in the context of the radial unit and protomap hypotheses. A broad spectrum of findings gave insight into the pathogenesis of cortical malformations and the biological bases for the evolution of the modern human neocortex. We examine the history and evidence behind the concept of early specification of neurons and provide the latest compendium of genes and signaling molecules involved in neuronal fate determination and specification. PMID:19380167

  3. Focal cortical dysplasias in autism spectrum disorders

    PubMed Central

    2013-01-01

    Background Previous reports indicate the presence of histological abnormalities in the brains of individuals with autism spectrum disorders (ASD) suggestive of a dysplastic process. In this study we identified areas of abnormal cortical thinning within the cerebral cortex of ASD individuals and examined the same for neuronal morphometric abnormalities by using computerized image analysis. Results The study analyzed celloidin-embedded and Nissl-stained serial full coronal brain sections of 7 autistic (ADI-R diagnosed) and 7 age/sex-matched neurotypicals. Sections were scanned and manually segmented before implementing an algorithm using Laplace’s equation to measure cortical width. Identified areas were then subjected to analysis for neuronal morphometry. Results of our study indicate the presence within our ASD population of circumscribed foci of diminished cortical width that varied among affected individuals both in terms of location and overall size with the frontal lobes being particularly involved. Spatial statistic indicated a reduction in size of neurons within affected areas. Granulometry confirmed the presence of smaller pyramidal cells and suggested a concomitant reduction in the total number of interneurons. Conclusions The neuropathology is consistent with a diagnosis of focal cortical dysplasia (FCD). Results from the medical literature (e.g., heterotopias) and our own study suggest that the genesis of this cortical malformation seemingly resides in the heterochronic divisions of periventricular germinal cells. The end result is that during corticogenesis radially migrating neuroblasts (future pyramidal cells) are desynchronized in their development from those that follow a tangential route (interneurons). The possible presence of a pathological mechanism in common among different conditions expressing an autism-like phenotype argue in favor of considering ASD a “sequence” rather than a syndrome. Focal cortical dysplasias in ASD may serve to

  4. The Computational Properties of a Simplified Cortical Column Model.

    PubMed

    Cain, Nicholas; Iyer, Ramakrishnan; Koch, Christof; Mihalas, Stefan

    2016-09-01

    The mammalian neocortex has a repetitious, laminar structure and performs functions integral to higher cognitive processes, including sensory perception, memory, and coordinated motor output. What computations does this circuitry subserve that link these unique structural elements to their function? Potjans and Diesmann (2014) parameterized a four-layer, two cell type (i.e. excitatory and inhibitory) model of a cortical column with homogeneous populations and cell type dependent connection probabilities. We implement a version of their model using a displacement integro-partial differential equation (DiPDE) population density model. This approach, exact in the limit of large homogeneous populations, provides a fast numerical method to solve equations describing the full probability density distribution of neuronal membrane potentials. It lends itself to quickly analyzing the mean response properties of population-scale firing rate dynamics. We use this strategy to examine the input-output relationship of the Potjans and Diesmann cortical column model to understand its computational properties. When inputs are constrained to jointly and equally target excitatory and inhibitory neurons, we find a large linear regime where the effect of a multi-layer input signal can be reduced to a linear combination of component signals. One of these, a simple subtractive operation, can act as an error signal passed between hierarchical processing stages.

  5. The Computational Properties of a Simplified Cortical Column Model

    PubMed Central

    Iyer, Ramakrishnan; Koch, Christof; Mihalas, Stefan

    2016-01-01

    The mammalian neocortex has a repetitious, laminar structure and performs functions integral to higher cognitive processes, including sensory perception, memory, and coordinated motor output. What computations does this circuitry subserve that link these unique structural elements to their function? Potjans and Diesmann (2014) parameterized a four-layer, two cell type (i.e. excitatory and inhibitory) model of a cortical column with homogeneous populations and cell type dependent connection probabilities. We implement a version of their model using a displacement integro-partial differential equation (DiPDE) population density model. This approach, exact in the limit of large homogeneous populations, provides a fast numerical method to solve equations describing the full probability density distribution of neuronal membrane potentials. It lends itself to quickly analyzing the mean response properties of population-scale firing rate dynamics. We use this strategy to examine the input-output relationship of the Potjans and Diesmann cortical column model to understand its computational properties. When inputs are constrained to jointly and equally target excitatory and inhibitory neurons, we find a large linear regime where the effect of a multi-layer input signal can be reduced to a linear combination of component signals. One of these, a simple subtractive operation, can act as an error signal passed between hierarchical processing stages. PMID:27617444

  6. Abnormalities in Structural Covariance of Cortical Gyrification in Parkinson's Disease

    PubMed Central

    Xu, Jinping; Zhang, Jiuquan; Zhang, Jinlei; Wang, Yue; Zhang, Yanling; Wang, Jian; Li, Guanglin; Hu, Qingmao; Zhang, Yuanchao

    2017-01-01

    Although abnormal cortical morphology and connectivity between brain regions (structural covariance) have been reported in Parkinson's disease (PD), the topological organizations of large-scale structural brain networks are still poorly understood. In this study, we investigated large-scale structural brain networks in a sample of 37 PD patients and 34 healthy controls (HC) by assessing the structural covariance of cortical gyrification with local gyrification index (lGI). We demonstrated prominent small-world properties of the structural brain networks for both groups. Compared with the HC group, PD patients showed significantly increased integrated characteristic path length and integrated clustering coefficient, as well as decreased integrated global efficiency in structural brain networks. Distinct distributions of hub regions were identified between the two groups, showing more hub regions in the frontal cortex in PD patients. Moreover, the modular analyses revealed significantly decreased integrated regional efficiency in lateral Fronto-Insula-Temporal module, and increased integrated regional efficiency in Parieto-Temporal module in the PD group as compared to the HC group. In summary, our study demonstrated altered topological properties of structural networks at a global, regional and modular level in PD patients. These findings suggests that the structural networks of PD patients have a suboptimal topological organization, resulting in less effective integration of information between brain regions. PMID:28326021

  7. Abnormalities in Structural Covariance of Cortical Gyrification in Parkinson's Disease.

    PubMed

    Xu, Jinping; Zhang, Jiuquan; Zhang, Jinlei; Wang, Yue; Zhang, Yanling; Wang, Jian; Li, Guanglin; Hu, Qingmao; Zhang, Yuanchao

    2017-01-01

    Although abnormal cortical morphology and connectivity between brain regions (structural covariance) have been reported in Parkinson's disease (PD), the topological organizations of large-scale structural brain networks are still poorly understood. In this study, we investigated large-scale structural brain networks in a sample of 37 PD patients and 34 healthy controls (HC) by assessing the structural covariance of cortical gyrification with local gyrification index (lGI). We demonstrated prominent small-world properties of the structural brain networks for both groups. Compared with the HC group, PD patients showed significantly increased integrated characteristic path length and integrated clustering coefficient, as well as decreased integrated global efficiency in structural brain networks. Distinct distributions of hub regions were identified between the two groups, showing more hub regions in the frontal cortex in PD patients. Moreover, the modular analyses revealed significantly decreased integrated regional efficiency in lateral Fronto-Insula-Temporal module, and increased integrated regional efficiency in Parieto-Temporal module in the PD group as compared to the HC group. In summary, our study demonstrated altered topological properties of structural networks at a global, regional and modular level in PD patients. These findings suggests that the structural networks of PD patients have a suboptimal topological organization, resulting in less effective integration of information between brain regions.

  8. Variability in Subcortical Aphasia Is Due to Variable Sites of Cortical Hypoperfusion

    ERIC Educational Resources Information Center

    Hillis, Argye E.; Barker, Peter B.; Wityk, Robert J.; Aldrich, Eric M.; Restrepo, Lucas; Breese, Elisabeth L.; Work, Melissa

    2004-01-01

    A variety of fluent and nonfluent aphasias have been reported after left basal ganglia stroke. It has been speculated that this heterogeneity may reflect variations in cortical hypoperfusion resulting from large vessel stenosis. To test this hypothesis, a consecutive series of 24 patients with left caudate infarct identified with…

  9. Variability in Subcortical Aphasia Is Due to Variable Sites of Cortical Hypoperfusion

    ERIC Educational Resources Information Center

    Hillis, Argye E.; Barker, Peter B.; Wityk, Robert J.; Aldrich, Eric M.; Restrepo, Lucas; Breese, Elisabeth L.; Work, Melissa

    2004-01-01

    A variety of fluent and nonfluent aphasias have been reported after left basal ganglia stroke. It has been speculated that this heterogeneity may reflect variations in cortical hypoperfusion resulting from large vessel stenosis. To test this hypothesis, a consecutive series of 24 patients with left caudate infarct identified with…

  10. Organizing Principles of Cortical Layer 6

    PubMed Central

    Briggs, Farran

    2009-01-01

    Neurons in the deepest layer of mammalian cerebral cortex are morphologically and physiological diverse and are situated in a strategic position to modulate neuronal activity locally and in other structures. The variety of neuronal circuits within which layer 6 neurons participate differs across species and cortical regions. However even amidst this diversity, common organizational features emerge. Examination of the anatomical and physiological characteristics of different classes of layer 6 neuron, each specialized to participate in distinct circuits, provides insight into the functional contributions of layer 6 neurons toward cortical information processing. PMID:20179784

  11. Elemental mercury poisoning probably causes cortical myoclonus.

    PubMed

    Ragothaman, Mona; Kulkarni, Girish; Ashraf, Valappil V; Pal, Pramod K; Chickabasavaiah, Yasha; Shankar, Susarla K; Govindappa, Srikanth S; Satishchandra, Parthasarthy; Muthane, Uday B

    2007-10-15

    Mercury toxicity causes postural tremors, commonly referred to as "mercurial tremors," and cerebellar dysfunction. A 23-year woman, 2 years after injecting herself with elemental mercury developed disabling generalized myoclonus and ataxia. Electrophysiological studies confirmed the myoclonus was probably of cortical origin. Her deficits progressed over 2 years and improved after subcutaneous mercury deposits at the injection site were surgically cleared. Myoclonus of cortical origin has never been described in mercury poisoning. It is important to ask patients presenting with jerks about exposure to elemental mercury even if they have a progressive illness, as it is a potentially reversible condition as in our patient.

  12. Posterior cortical atrophy: a brief review.

    PubMed

    Kirshner, Howard S; Lavin, Patrick J M

    2006-11-01

    Posterior cortical atrophy is a striking clinical syndrome in which a dementing illness begins with visual symptoms. Initially, the problem may seem to be loss of elementary vision, but over time the patient develops features of visual agnosia, topographical difficulty, optic ataxia, simultanagnosia, ocular apraxia (Balint's syndrome), alexia, acalculia, right-left confusion, and agraphia (Gerstmann's syndrome), and later a more generalized dementia. Occasional patients have visual hallucinations and signs of Parkinson's disease or Lewy body dementia. A number of different neuropathologic disorders are associated with posterior cortical atrophy.

  13. Cortical Networks for Visual Self-Recognition

    NASA Astrophysics Data System (ADS)

    Sugiura, Motoaki

    This paper briefly reviews recent developments regarding the brain mechanisms of visual self-recognition. A special cognitive mechanism for visual self-recognition has been postulated based on behavioral and neuropsychological evidence, but its neural substrate remains controversial. Recent functional imaging studies suggest that multiple cortical mechanisms play self-specific roles during visual self-recognition, reconciling the existing controversy. Respective roles for the left occipitotemporal, right parietal, and frontal cortices in symbolic, visuospatial, and conceptual aspects of self-representation have been proposed.

  14. The warning-sign hierarchy between quantitative subcortical motor mapping and continuous motor evoked potential monitoring during resection of supratentorial brain tumors.

    PubMed

    Seidel, Kathleen; Beck, Jürgen; Stieglitz, Lennart; Schucht, Philippe; Raabe, Andreas

    2013-02-01

    Mapping and monitoring are believed to provide an early warning sign to determine when to stop tumor removal to avoid mechanical damage to the corticospinal tract (CST). The objective of this study was to systematically compare subcortical monopolar stimulation thresholds (1-20 mA) with direct cortical stimulation (DCS)-motor evoked potential (MEP) monitoring signal abnormalities and to correlate both with new postoperative motor deficits. The authors sought to define a mapping threshold and DCS-MEP monitoring signal changes indicating a minimal safe distance from the CST. A consecutive cohort of 100 patients underwent tumor surgery adjacent to the CST while simultaneous subcortical motor mapping and DCS-MEP monitoring was used. Evaluation was done regarding the lowest subcortical mapping threshold (monopolar stimulation, train of 5 stimuli, interstimulus interval 4.0 msec, pulse duration 500 μsec) and signal changes in DCS-MEPs (same parameters, 4 contact strip electrode). Motor function was assessed 1 day after surgery, at discharge, and at 3 months postoperatively. The lowest individual motor thresholds (MTs) were as follows (MT in mA, number of patients): > 20 mA, n = 12; 11-20 mA, n = 13; 6-10 mA, n = 20; 4-5 mA, n = 30; and 1-3 mA, n = 25. Direct cortical stimulation showed stable signals in 70 patients, unspecific changes in 18, irreversible alterations in 8, and irreversible loss in 4 patients. At 3 months, 5 patients had a postoperative new or worsened motor deficit (lowest mapping MT 20 mA, 13 mA, 6 mA, 3 mA, and 1 mA). In all 5 patients DCS-MEP monitoring alterations were documented (2 sudden irreversible threshold increases and 3 sudden irreversible MEP losses). Of these 5 patients, 2 had vascular ischemic lesions (MT 20 mA, 13 mA) and 3 had mechanical CST damage (MT 1 mA, 3 mA, and 6 mA; in the latter 2 cases the resection continued after mapping and severe DCS-MEP alterations occurred thereafter). In 80% of patients with a mapping MT of 1-3 mA and in

  15. Cortically projecting basal forebrain parvalbumin neurons regulate cortical gamma band oscillations.

    PubMed

    Kim, Tae; Thankachan, Stephen; McKenna, James T; McNally, James M; Yang, Chun; Choi, Jee Hyun; Chen, Lichao; Kocsis, Bernat; Deisseroth, Karl; Strecker, Robert E; Basheer, Radhika; Brown, Ritchie E; McCarley, Robert W

    2015-03-17

    Cortical gamma band oscillations (GBO, 30-80 Hz, typically ∼40 Hz) are involved in higher cognitive functions such as feature binding, attention, and working memory. GBO abnormalities are a feature of several neuropsychiatric disorders associated with dysfunction of cortical fast-spiking interneurons containing the calcium-binding protein parvalbumin (PV). GBO vary according to the state of arousal, are modulated by attention, and are correlated with conscious awareness. However, the subcortical cell types underlying the state-dependent control of GBO are not well understood. Here we tested the role of one cell type in the wakefulness-promoting basal forebrain (BF) region, cortically projecting GABAergic neurons containing PV, whose virally transduced fibers we found apposed cortical PV interneurons involved in generating GBO. Optogenetic stimulation of BF PV neurons in mice preferentially increased cortical GBO power by entraining a cortical oscillator with a resonant frequency of ∼40 Hz, as revealed by analysis of both rhythmic and nonrhythmic BF PV stimulation. Selective saporin lesions of BF cholinergic neurons did not alter the enhancement of cortical GBO power induced by BF PV stimulation. Importantly, bilateral optogenetic inhibition of BF PV neurons decreased the power of the 40-Hz auditory steady-state response, a read-out of the ability of the cortex to generate GBO used in clinical studies. Our results are surprising and novel in indicating that this presumptively inhibitory BF PV input controls cortical GBO, likely by synchronizing the activity of cortical PV interneurons. BF PV neurons may represent a previously unidentified therapeutic target to treat disorders involving abnormal GBO, such as schizophrenia.

  16. Cortical Amyloid β Deposition and Current Depressive Symptoms in Alzheimer Disease and Mild Cognitive Impairment.

    PubMed

    Chung, Jun Ku; Plitman, Eric; Nakajima, Shinichiro; Chakravarty, M Mallar; Caravaggio, Fernando; Gerretsen, Philip; Iwata, Yusuke; Graff-Guerrero, Ariel

    2016-05-01

    Depressive symptoms are frequently seen in patients with dementia and mild cognitive impairment (MCI). Evidence suggests that there may be a link between current depressive symptoms and Alzheimer disease (AD)-associated pathological changes, such as an increase in cortical amyloid-β (Aβ). However, limited in vivo studies have explored the relationship between current depressive symptoms and cortical Aβ in patients with MCI and AD. Our study, using a large sample of 455 patients with MCI and 153 patients with AD from the Alzheimer's disease Neuroimaging Initiatives, investigated whether current depressive symptoms are related to cortical Aβ deposition. Depressive symptoms were assessed using the Geriatric Depression Scale and Neuropsychiatric Inventory-depression/dysphoria. Cortical Aβ was quantified using positron emission tomography with the Aβ probe(18)F-florbetapir (AV-45).(18)F-florbetapir standardized uptake value ratio (AV-45 SUVR) from the frontal, cingulate, parietal, and temporal regions was estimated. A global AV-45 SUVR, defined as the average of frontal, cingulate, precuneus, and parietal cortex, was also used. We observed that current depressive symptoms were not related to cortical Aβ, after controlling for potential confounds, including history of major depression. We also observed that there was no difference in cortical Aβ between matched participants with high and low depressive symptoms, as well as no difference between matched participants with the presence and absence of depressive symptoms. The association between depression and cortical Aβ deposition does not exist, but the relationship is highly influenced by stressful events in the past, such as previous depressive episodes, and complex interactions of different pathways underlying both depression and dementia. © The Author(s) 2015.

  17. Layer- and area-specific actions of norepinephrine on cortical synaptic transmission.

    PubMed

    Salgado, Humberto; Treviño, Mario; Atzori, Marco

    2016-06-15

    The cerebral cortex is a critical target of the central noradrenergic system. The importance of norepinephrine (NE) in the regulation of cortical activity is underscored by clinical findings that involve this catecholamine and its receptor subtypes in the regulation of a large number of emotional and cognitive functions and illnesses. In this review, we highlight diverse effects of the LC/NE system in the mammalian cortex. Indeed, electrophysiological, pharmacological, and behavioral studies in the last few decades reveal that NE elicits a mixed repertoire of excitatory, inhibitory, and biphasic effects on the firing activity and transmitter release of cortical neurons. At the intrinsic cellular level, NE can produce a series of effects similar to those elicited by other monoamines or acetylcholine, associated with systemic arousal. At the synaptic level, NE induces numerous acute changes in synaptic function, and ׳gates' the induction of long-term plasticity of glutamatergic synapses, consisting in an enhancement of engaged and relevant cortical synapses and/or depression of unengaged synapses. Equally important in shaping cortical function, in many cortical areas NE promotes a characteristic, most often reversible, increase in the gain of local inhibitory synapses, whose extent and temporal properties vary between different areas and sometimes even between cortical layers of the same area. While we are still a long way from a comprehensive theory of the function of the LC/NE system, its cellular, synaptic, and plastic effects are consistent with the hypothesis that noradrenergic modulation is critical in coordinating the activity of cortical and subcortical circuits for the integration of sensory activity and working memory. This article is part of a Special Issue entitled SI: Noradrenergic System.

  18. Cortical Drive to Breathe during Wakefulness in Patients with Obstructive Sleep Apnea Syndrome

    PubMed Central

    Launois, Claire; Attali, Valérie; Georges, Marjolaine; Raux, Mathieu; Morawiec, Elise; Rivals, Isabelle; Arnulf, Isabelle; Similowski, Thomas

    2015-01-01

    Study Objectives: The obstructive sleep apnea syndrome (OSAS) involves recurrent sleep-related upper airways (UA) collapse. UA mechanical properties and neural control are altered, imposing a mechanical load on inspiration. UA collapse does not occur during wakefulness, hence arousal-dependent compensation. Experimental inspiratory loading in normal subjects elicits respiratory-related cortical activity. The objective of this study was to test whether awake OSAS patients would exhibit a similar cortical activity. Design: Descriptive physiology study. Setting: Sleep laboratory in a large university affiliated tertiary hospital. Patients: 26 patients with moderate OSAS according to polysomnography (5 < apnea-hypopnea index [AHI] ≤ 30, n = 14) or severe OSAS (AHI > 30, n = 12); 13 non-OSAS patients for comparison. Interventions: None. Measurements: Respiratory time-locked electroencephalographic segments ensemble averaged and analyzed for slow premotor potentials preceding inspiration (“pre-inspiratory potentials” [PIPs]). Results: PIPs were present in 1/13 controls and 11/26 patients (P = 0.0336; 4/14 “moderate” and 7/12 “severe” patients). Awake OSAS patients therefore exhibit respiratory-related cortical activity during quiet breathing significantly more frequently than non-OSAS individuals. The corresponding PIPs resemble those observed during prepared voluntary inspirations and in response to experimental inspiratory loads in normal subjects, which involve a cortical network comprising the supplementary motor area. Conclusions: A respiratory-related cortical activity could contribute to the increased neural drive to upper airway and to inspiratory muscles that has previously been described in obstructive sleep apnea, and could therefore contribute to the arousal-dependent compensation of upper airway abnormalities. Whether or not such cortical compensatory mechanisms have cognitive consequences remains to be determined. Citation: Launois C, Attali V

  19. A mathematical model of dysfunction of the thalamo-cortical loop in schizophrenia.

    PubMed

    Rosjat, Nils; Popovych, Svitlana; Daun-Gruhn, Silvia

    2014-10-18

    Recent experimental results suggest that impairment of auditory information processing in the thalamo-cortical loop is crucially related to schizophrenia. Large differences between schizophrenia patients and healthy controls were found in the cortical EEG signals. We derive a phenomenological mathematical model, based on coupled phase oscillators with continuously distributed frequencies to describe the neural activity of the thalamo-cortical loop. We examine the influence of the bidirectional coupling strengths between the thalamic and the cortical area with regard to the phase-locking effects observed in the experiments. We extend this approach to a model consisting of a thalamic area coupled to two cortical areas, each comprising a set of nonidentical phase oscillators. In the investigations of our model, we applied the Ott-Antonsen theory and the Pikovsky-Rosenblum reduction methods to the original system. The results derived from our mathematical model satisfactorily reproduce the experimental data obtained by EEG measurements. Furthermore, they show that modifying the coupling strength from the thalamic region to a cortical region affects the duration of phase synchronization, while a change in the feedback to the thalamus affects the strength of synchronization in the cortex. In addition, our model provides an explanation in terms of nonlinear dynamics as to why brain waves desynchronize after a given phase reset. Our model can explain functional differences seen between EEG records of healthy subjects and schizophrenia patients on a system theoretic basis. Because of this and its predictive character, the model may be considered to pave the way towards an early and reliable clinical detection of schizophrenia that is dependent on the interconnections between the thalamic and cortical regions. In particular, the model parameter that describes the strength of this connection can be used for a diagnostic classification of schizophrenia patients.

  20. Cortical Amyloid β Deposition and Current Depressive Symptoms in Alzheimer Disease and Mild Cognitive Impairment

    PubMed Central

    Chung, Jun Ku; Plitman, Eric; Nakajima, Shinichiro; Chakravarty, M. Mallar; Caravaggio, Fernando; Gerretsen, Philip; Iwata, Yusuke; Graff-Guerrero, Ariel

    2016-01-01

    Depressive symptoms are frequently seen in patients with dementia and mild cognitive impairment (MCI). Evidence suggests that there may be a link between current depressive symptoms and Alzheimer disease (AD)-associated pathological changes, such as an increase in cortical amyloid-β (Aβ). However, limited in vivo studies have explored the relationship between current depressive symptoms and cortical Aβ in patients with MCI and AD. Our study, using a large sample of 455 patients with MCI and 153 patients with AD from the Alzheimer’s disease Neuroimaging Initiatives, investigated whether current depressive symptoms are related to cortical Aβ deposition. Depressive symptoms were assessed using the Geriatric Depression Scale and Neuropsychiatric Inventory-depression/dysphoria. Cortical Aβ was quantified using positron emission tomography with the Aβ probe 18F-florbetapir (AV-45). 18F-florbetapir standardized uptake value ratio (AV-45 SUVR) from the frontal, cingulate, parietal, and temporal regions was estimated. A global AV-45 SUVR, defined as the average of frontal, cingulate, precuneus, and parietal cortex, was also used. We observed that current depressive symptoms were not related to cortical Aβ, after controlling for potential confounds, including history of major depression. We also observed that there was no difference in cortical Aβ between matched participants with high and low depressive symptoms, as well as no difference between matched participants with the presence and absence of depressive symptoms. The association between depression and cortical Aβ deposition does not exist, but the relationship is highly influenced by stressful events in the past, such as previous depressive episodes, and complex interactions of different pathways underlying both depression and dementia. PMID:26400248

  1. Cortical thickness, volume and surface area in patients with bipolar disorder types I and II

    PubMed Central

    Abé, Christoph; Ekman, Carl-Johan; Sellgren, Carl; Petrovic, Predrag; Ingvar, Martin; Landén, Mikael

    2016-01-01

    Background Bipolar disorder (BD) is a common chronic psychiatric disorder mainly characterized by episodes of mania, hypomania and depression. The disorder is associated with cognitive impairments and structural brain abnormalities, such as lower cortical volumes in primarily frontal brain regions than healthy controls. Although bipolar disorder types I (BDI) and II (BDII) exhibit different symptoms and severity, previous studies have focused on BDI. Furthermore, the most frequently investigated measure in this population is cortical volume. The aim of our study was to investigate abnormalities in patients with BDI and BDII by simultaneously analyzing cortical volume, thickness and surface area, which yields more information about disease- and symptom-related neurobiology. Methods We used MRI to measure cortical volume, thickness and area in patients with BDI and BDII as well as in healthy controls. The large study cohort enabled us to adjust for important confounding factors. Results We included 81 patients with BDI, 59 with BDII and 85 controls in our analyses. Cortical volume, thickness and surface area abnormalities were present in frontal, temporal and medial occipital regions in patients with BD. Lithium and antiepileptic drug use had an effect on the observed differences in medial occipital regions. Patients with the subtypes BDI and BDII displayed common cortical abnormalities, such as lower volume, thickness and surface area than healthy controls in frontal brain regions but differed in temporal and medial prefrontal regions, where only those with BDI had abnormally low cortical volume and thickness. Limitations The group differences can be explained by progressive changes, but also by premorbid conditions. They could also have been influenced by unknown factors, such as social, environmental or genetic factors. Conclusion Our findings suggest diagnosis-related neurobiological differences between the BD subtypes, which could explain distinct symptoms and

  2. Visualization of an actively bleeding cortical vessel into the subdural space by CT angiography.

    PubMed

    Dalfino, John C; Boulos, Alan S

    2010-10-01

    Spontaneous subdural hematomas of arterial origin are rare with only a few published case reports in the literature. In the CT era, vessel imaging of extra-axial hematomas is not commonly performed. In this case report we present a patient with a large, spontaneous acute subdural hematoma that demonstrated active contrast extravasation from a small cortical vessel on CT angiography. During surgical evacuation the vessel was confirmed to be a small cortical artery that was bulging through the arachnoid membrane and bleeding into the subdural space. The historical, radiographic, and clinical aspects of this unusual cause of subdural hematoma are discussed.

  3. Low-frequency hippocampal–cortical activity drives brain-wide resting-state functional MRI connectivity

    PubMed Central

    Chan, Russell W.; Leong, Alex T. L.; Ho, Leon C.; Gao, Patrick P.; Wong, Eddie C.; Dong, Celia M.; Wang, Xunda; He, Jufang; Chan, Ying-Shing; Lim, Lee Wei; Wu, Ed X.

    2017-01-01

    The hippocampus, including the dorsal dentate gyrus (dDG), and cortex engage in bidirectional communication. We propose that low-frequency activity in hippocampal–cortical pathways contributes to brain-wide resting-state connectivity to integrate sensory information. Using optogenetic stimulation and brain-wide fMRI and resting-state fMRI (rsfMRI), we determined the large-scale effects of spatiotemporal-specific downstream propagation of hippocampal activity. Low-frequency (1 Hz), but not high-frequency (40 Hz), stimulation of dDG excitatory neurons evoked robust cortical and subcortical brain-wide fMRI responses. More importantly, it enhanced interhemispheric rsfMRI connectivity in various cortices and hippocampus. Subsequent local field potential recordings revealed an increase in slow oscillations in dorsal hippocampus and visual cortex, interhemispheric visual cortical connectivity, and hippocampal–cortical connectivity. Meanwhile, pharmacological inactivation of dDG neurons decreased interhemispheric rsfMRI connectivity. Functionally, visually evoked fMRI responses in visual regions also increased during and after low-frequency dDG stimulation. Together, our results indicate that low-frequency activity robustly propagates in the dorsal hippocampal–cortical pathway, drives interhemispheric cortical rsfMRI connectivity, and mediates visual processing. PMID:28760982

  4. Asymmetry of prefrontal cortical convolution complexity in males with attention-deficit/hyperactivity disorder using fractal information dimension.

    PubMed

    Li, Xiaobo; Jiang, Jiefeng; Zhu, Wanlin; Yu, Chunshui; Sui, Manqiu; Wang, Yufeng; Jiang, Tianzi

    2007-11-01

    Prefrontal cortex, known to be a crucial region for the function of attention, is generally thought to be largely associated with the pathogenesis of attention-deficit hyperactivity disorder (ADHD). Most previous structural imaging studies of ADHD reported abnormality of grey matter volume in prefrontal region. However, volume measure is affected by the size of the interrogated brain, which may cause the inconsistence of the volume based findings. The purpose of the current paper is to use a scale-free measure, fractal information dimension (FID), to assess the prefrontal cortical convolution complexity and asymmetry in ADHD patients. MRI scans from 12 boys with ADHD and 11 controls were carefully processed. Prefrontal cortex was outlined manually. FIDs of bilateral prefrontal cortical surface were examined in each case. Group differences of the bilateral prefrontal cortical convolution complexities and the asymmetry pattern were statistically tested. We found a left-greater-than-right prefrontal cortical convolution complexity pattern in both groups. However, compared with healthy controls, the left prefrontal cortical convolution complexities of ADHD patients were significantly reduced, resulting in significant reduction of the normal left-greater-than-right cortical convolution complexity asymmetry pattern. This study confirms and extends the existing anatomical knowledge about the brains of people with ADHD. The cortical convolution analysis method may also be applied to quantitatively assess changes in other neuropsychiatric syndromes as well.

  5. Cortical Stimulation Concurrent With Skilled Motor Training Improves Forelimb Function and Enhances Motor Cortical Reorganization Following Controlled Cortical Impact.

    PubMed

    Jefferson, Stephanie C; Clayton, Elyse Renee; Donlan, Nicole A; Kozlowski, Dorothy Annette; Jones, Theresa A; Adkins, DeAnna Lynn

    2016-02-01

    Electrical and magnetic brain stimulation can improve motor function following stroke in humans, rats, and nonhuman primates, especially when paired with rehabilitative training (RT). Previously, we found in rodent stroke models that epidural electrical cortical stimulation (CS) of the ipsilesional motor cortex (MC) combined with motor RT enhances motor function and motor cortical plasticity. It was unknown whether CS following experimental traumatic brain injury (TBI) would have similar effects. To test the effects of CS combined with motor training after moderate/severe TBI on behavioral outcome and motor cortical organization. Following unilateral controlled cortical impact (CCI) over the caudal forelimb area of the MC in adult male rats, forelimb reach training was administered daily for 9 weeks concurrently with subthreshold, 100-Hz monopolar CS or no-stimulation control procedures. The rate and magnitude of behavioral improvements and changes in forelimb movement representations in the injured MC as revealed by intracortical microstimulation were measured. CCI resulted in severe motor impairments persisting throughout the 9 weeks of training in both groups, but CS-treated animals had significantly greater behavioral improvements. CS also increased wrist motor cortical representation, one of the main movements used in the training task, when compared with RT alone. However, the overall recovery level was modest, leaving animals still extremely impaired. These data suggest that CS may be useful for improving rehabilitation efficacy after TBI but also raise the possibility that the CS parameters that are highly effective following stroke are suboptimal after moderate/severe TBI. © The Author(s) 2015.

  6. Deep brain and cortical stimulation for epilepsy.

    PubMed

    Sprengers, Mathieu; Vonck, Kristl; Carrette, Evelien; Marson, Anthony G; Boon, Paul

    2017-07-18

    Despite optimal medical treatment, including epilepsy surgery, many epilepsy patients have uncontrolled seizures. Since the 1970s interest has grown in invasive intracranial neurostimulation as a treatment for these patients. Intracranial stimulation includes both deep brain stimulation (DBS) (stimulation through depth electrodes) and cortical stimulation (subdural electrodes). This is an updated version of a previous Cochrane review published in 2014. To assess the efficacy, safety and tolerability of DBS and cortical stimulation for refractory epilepsy based on randomized controlled trials (RCTs). We searched the Cochrane Epilepsy Group Specialized Register on 29 September 2015, but it was not necessary to update this search, because records in the Specialized Register are included in CENTRAL. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 11, 5 November 2016), PubMed (5 November 2016), ClinicalTrials.gov (5 November 2016), the WHO International Clinical Trials Registry Platform ICTRP (5 November 2016) and reference lists of retrieved articles. We also contacted device manufacturers and other researchers in the field. No language restrictions were imposed. RCTs comparing deep brain or cortical stimulation versus sham stimulation, resective surgery, further treatment with antiepileptic drugs or other neurostimulation treatments (including vagus nerve stimulation). Four review authors independently selected trials for inclusion. Two review authors independently extracted the relevant data and assessed trial quality and overall quality of evidence. The outcomes investigated were seizure freedom, responder rate, percentage seizure frequency reduction, adverse events, neuropsychological outcome and quality of life. If additional data were needed, the study investigators were contacted. Results were analysed and reported separately for different intracranial targets for reasons of clinical heterogeneity

  7. Deep brain and cortical stimulation for epilepsy.

    PubMed

    Sprengers, Mathieu; Vonck, Kristl; Carrette, Evelien; Marson, Anthony G; Boon, Paul

    2014-06-17

    Despite optimal medical treatment, including epilepsy surgery, many epilepsy patients have uncontrolled seizures. In the last decades, interest has grown in invasive intracranial neurostimulation as a treatment for these patients. Intracranial stimulation includes both deep brain stimulation (DBS) (stimulation through depth electrodes) and cortical stimulation (subdural electrodes). To assess the efficacy, safety and tolerability of deep brain and cortical stimulation for refractory epilepsy based on randomized controlled trials. We searched PubMed (6 August 2013), the Cochrane Epilepsy Group Specialized Register (31 August 2013), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 7 of 12) and reference lists of retrieved articles. We also contacted device manufacturers and other researchers in the field. No language restrictions were imposed. Randomized controlled trials (RCTs) comparing deep brain or cortical stimulation to sham stimulation, resective surgery or further treatment with antiepileptic drugs. Four review authors independently selected trials for inclusion. Two review authors independently extracted the relevant data and assessed trial quality and overall quality of evidence. The outcomes investigated were seizure freedom, responder rate, percentage seizure frequency reduction, adverse events, neuropsychological outcome and quality of life. If additional data were needed, the study investigators were contacted. Results were analysed and reported separately for different intracranial targets for reasons of clinical heterogeneity. Ten RCTs comparing one to three months of intracranial neurostimulation to sham stimulation were identified. One trial was on anterior thalamic DBS (n = 109; 109 treatment periods); two trials on centromedian thalamic DBS (n = 20; 40 treatment periods), but only one of the trials (n = 7; 14 treatment periods) reported sufficient information for inclusion in the quantitative meta

  8. Cortical activity in the null space: permitting preparation without movement.

    PubMed

    Kaufman, Matthew T; Churchland, Mark M; Ryu, Stephen I; Shenoy, Krishna V

    2014-03-01

    Neural circuits must perform computations and then selectively output the results to other circuits. Yet synapses do not change radically at millisecond timescales. A key question then is: how is communication between neural circuits controlled? In motor control, brain areas directly involved in driving movement are active well before movement begins. Muscle activity is some readout of neural activity, yet it remains largely unchanged during preparation. Here we find that during preparation, while the monkey holds still, changes in motor cortical activity cancel out at the level of these population readouts. Motor cortex can thereby prepare the movement without prematurely causing it. Further, we found evidence that this mechanism also operates in dorsal premotor cortex, largely accounting for how preparatory activity is attenuated in primary motor cortex. Selective use of 'output-null' vs. 'output-potent' patterns of activity may thus help control communication to the muscles and between these brain areas.

  9. Cortical activity in the null space: permitting preparation without movement

    PubMed Central

    Kaufman, Matthew T.; Churchland, Mark M.; Ryu, Stephen I.; Shenoy, Krishna V.

    2014-01-01

    Neural circuits must perform computations and then selectively output the results to other circuits. Yet synapses do not change radically at millisecond timescales. A key question then is: how is communication between neural circuits controlled? In motor control, brain areas directly involved in driving movement are active well before movement begins. Muscle activity is some readout of neural activity, yet remains largely unchanged during preparation. Here we find that during preparation, while the monkey holds still, changes in motor cortical activity cancel out at the level of these population readouts. Motor cortex can thereby prepare the movement without prematurely causing it. Further, we found evidence that this mechanism also operates in dorsal premotor cortex (PMd), largely accounting for how preparatory activity is attenuated in primary motor cortex (M1). Selective use of “output-null” vs. “output-potent” patterns of activity may thus help control communication to the muscles and between these brain areas. PMID:24487233

  10. Acute Cortical Transhemispheric Diaschisis after Unilateral Traumatic Brain Injury.

    PubMed

    Le Prieult, Florie; Thal, Serge C; Engelhard, Kristin; Imbrosci, Barbara; Mittmann, Thomas

    2017-03-01

    Focal neocortical brain injuries lead to functional alterations, which can spread beyond lesion-neighboring brain areas. The undamaged hemisphere and its associated disturbances after a unilateral lesion, so-called transhemispheric diaschisis, have been progressively disclosed over the last decades; they are strongly involved in the pathophysiology and, potentially, recovery of brain injuries. Understanding the temporal dynamics of these transhemispheric functional changes is crucial to decipher the role of the undamaged cortex in the processes of functional reorganization at different stages post-lesion. In this regard, little is known about the acute-subacute processes after 24-48 h in the brain hemisphere contralateral to injury. In the present study, we performed a controlled cortical impact to produce a unilateral traumatic brain injury (TBI) in the motor and somatosensory cortex of mice. In vitro extracellular multi-unit recordings from large neuronal populations, together with single-cell patch-clamp recordings in the cortical network contralateral to the lesion, revealed a strong, but transient, neuronal hyperactivity as early as 24-48 h post-TBI. This abnormal excitable state in the intact hemisphere was not accompanied by alterations in neuronal intrinsic properties, but it was associated with an impairment of the phasic gamma aminobutyric acid (GABA)ergic transmission and an increased expression of GABAA receptor subunits related to tonic inhibition exclusively in the contralateral hemisphere. These data unravel a series of early transhemispheric functional alterations after diffuse unilateral cortical injury, which may compensate and stabilize the disrupted brain functions. Therefore, our findings support the hypothesis that the undamaged hemisphere could play a significant role in early functional reorganization processes after a TBI.

  11. Variations in mineralization affect the stress and strain distributions in cortical and trabecular bone.

    PubMed

    van Ruijven, L J; Mulder, L; van Eijden, T M G J

    2007-01-01

    The mechanical properties of bone depend largely on its degree and distribution of mineralization. The present study analyzes the effect of an inhomogeneous distribution of mineralization on the stress and strain distributions in the human mandibular condyle during static clenching. A condyle was scanned with a micro-CT scanner to create a finite element model. For every voxel the degree of mineralization (DMB) was determined from the micro-CT scan. The Young's moduli of the elements were calculated from the DMB using constant, linear, and cubic relations, respectively. Stresses, strains, and displacements in cortical and trabecular bone, as well as the condylar deformation (extension along the antero-posterion axis) and compliance were compared. Over 90% of the bone mineral was located in the cortical bone. The DMB showed large variations in both cortical bone (mean: 884, SD: 111 mg/cm(3)) and trabecular bone (mean: 738, SD: 101 mg/cm(3)). Variations of the stresses and the strains were small in cortical bone, but large in trabecular bone. In the cortical bone an inhomogeneous mineral distribution increased the stresses and the strains. In the trabecular bone, however, it decreased the stresses and increased the strains. Furthermore, the condylar compliance remained relatively constant, but the condylar deformation doubled. It was concluded that neglect of the inhomogeneity of the mineral distribution results in a large underestimation of the stresses and strains of possibly more than 50%. The stiffness of trabecular bone strongly influences the condylar deformation. Vice versa, the condylar deformation largely determines the magnitude of the strains in the trabecular bone.

  12. Current dipole orientation and distribution of epileptiform activity correlates with cortical thinning in left mesiotemporal epilepsy

    PubMed Central

    Reinsberger, Claus; Tanaka, Naoaki; Cole, Andrew J.; Woo Lee, Jong; Dworetzky, Barbara A.; Bromfield, Edward B.; Hamiwka, Lorie; Bourgeois, Blaise F.; Golby, Alexandra J.; Madsen, Joseph R.; Stufflebeam, Steven M.

    2011-01-01

    To evaluate cortical architecture in mesial temporal lobe epilepsy (MTLE) with respect to electrophysiology, we analyze both magnetic resonance imaging (MRI) and magnetoencephalography (MEG) in 19 patients with left MTLE. We divide the patients into two groups: 9 patients (Group A) had vertically oriented antero-medial equivalent current dipoles (ECDs). 10 patients (Group B) had ECDs that were diversely oriented and widely distributed. Group analysis of MRI data showed widespread cortical thinning in Group B compared with Group A, in the left hemisphere involving the cingulate, supramarginal, occipito-temporal and parahippocampal gyri, precuneus and parietal lobule, and in the right hemisphere involving the fronto-medial, -central and -basal gyri and the precuneus. These results suggest that regardless of the presence of hippocampal sclerosis, in a subgroup of patients with MTLE a large cortical network is affected. This finding may, in part, explain the unfavorable outcome in some MTLE patients after epilepsy surgery. PMID:20472073

  13. Current dipole orientation and distribution of epileptiform activity correlates with cortical thinning in left mesiotemporal epilepsy.

    PubMed

    Reinsberger, Claus; Tanaka, Naoaki; Cole, Andrew J; Lee, Jong Woo; Dworetzky, Barbara A; Bromfield, Edward B; Hamiwka, Lorie; Bourgeois, Blaise F; Golby, Alexandra J; Madsen, Joseph R; Stufflebeam, Steven M

    2010-10-01

    To evaluate cortical architecture in mesial temporal lobe epilepsy (MTLE) with respect to electrophysiology, we analyze both magnetic resonance imaging (MRI) and magnetoencephalography (MEG) in 19 patients with left MTLE. We divide the patients into two groups: 9 patients (Group A) have vertically oriented antero-medial equivalent current dipoles (ECDs). 10 patients (Group B) have ECDs that are diversely oriented and widely distributed. Group analysis of MRI data shows widespread cortical thinning in Group B compared with Group A, in the left hemisphere involving the cingulate, supramarginal, occipitotemporal and parahippocampal gyri, precuneus and parietal lobule, and in the right hemisphere involving the fronto-medial, -central and -basal gyri and the precuneus. These results suggest that regardless of the presence of hippocampal sclerosis, in a subgroup of patients with MTLE a large cortical network is affected. This finding may, in part, explain the unfavorable outcome in some MTLE patients after epilepsy surgery.

  14. Three-Dimensional Balance of Cortical Tension and Axial Contractility Enables Fast Amoeboid Migration

    PubMed Central

    Álvarez-González, Begoña; Meili, Ruedi; Bastounis, Effie; Firtel, Richard A.; Lasheras, Juan C.; del Álamo, Juan C.

    2015-01-01

    Fast amoeboid migration requires cells to apply mechanical forces on their surroundings via transient adhesions. However, the role these forces play in controlling cell migration speed remains largely unknown. We used three-dimensional force microscopy to measure the three-dimensional forces exerted by chemotaxing Dictyostelium cells, and examined wild-type cells as well as mutants with defects in contractility, internal F-actin crosslinking, and cortical integrity. We showed that cells pull on their substrate adhesions using two distinct, yet interconnected mechanisms: axial actomyosin contractility and cortical tension. We found that the migration speed increases when axial contractility overcomes cortical tension to produce the cell shape changes needed for locomotion. We demonstrated that the three-dimensional pulling forces generated by both mechanisms are internally balanced by an increase in cytoplasmic pressure that allows cells to push on their substrate without adhering to it, and which may be relevant for amoeboid migration in complex three-dimensional environments. PMID:25692587

  15. Potentiation of the depression by adenosine of rat cerebral cortical neurones by progestational agents.

    PubMed Central

    Phillis, J. W.

    1986-01-01

    The effects of four progestational agents pregnenolone sulphate, cyproterone acetate, norethindrone acetate and progesterone, on adenosine-evoked depression of the firing of rat cerebral cortical neurones have been studied. When applied iontophoretically, pregnenolone sulphate, cyproterone, and norethindrone enhanced the actions of iontophoretically applied adenosine and failed to potentiate the depressant effects of adenosine 5'-N-ethylcarboxamide and gamma-aminobutyric acid. Cyproterone acetate (50 micrograms kg-1) and progesterone (200 micrograms kg-1) administered intravenously enhanced the depressant actions of iontophoretically applied adenosine. When applied by large currents, cyproterone, and less frequently norethindrone, depressed the firing of cerebral cortical neurones. The depressant effects of cyproterone were antagonized by caffeine. Pregnenolone sulphate tended to excite cortical neurones but neither this action, nor its potentiation of adenosine were reproduced by application of sulphate ions. It is hypothesized that some of the psychotropic actions of progestational agents may involve an enhancement of 'purinergic' tone in the central nervous system. PMID:3814905

  16. Bilateral Symmetrical Cortical Osteolytic Lesions in Two Patients with Gaucher Disease

    PubMed Central

    Oppenheim, IM; Medina Canon, A; Barcenas, W; Groden, C; Goker-Alpan, O; Resnik, C; Sidransky, E

    2012-01-01

    Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder characterized by the reduced or absent activity of glucocerebrosidase. The disease is split into three types. Type 3, or chronic neuronopathic GD, manifests with heterogeneous clinical presentations. Skeletal manifestations of GD can include abnormal bone remodeling resulting in the characteristic Erlenmeyer flask deformities, painful bone crises, osteopenia, and an increased frequency of fractures. Osteolytic lesions can also occur, but are rare, and tend to be large expanding intramedullary lesions with cortical thinning. We present two adolescent patients with type 3 GD who developed bilateral symmetrical cortical osteolytic lesions. The lesions in both cases demonstrate predominant cortical scalloping with fairly indolent growth. Neither patient manifests some of the more common bony manifestations of GD; the Erlenmeyer flask deformity, bone crises, or osteonecrosis. These atypical and unique skeletal findings in two unrelated probands with type 3 GD further expands the extent of phenotypic variation encountered in this single gene disorder. PMID:21935720

  17. Cortico-Cortical Interactions during Acquisition and Use of a Neuroprosthetic Skill

    PubMed Central

    Wander, Jeremiah D.; Sarma, Devapratim; Johnson, Lise A.; Fetz, Eberhard E.; Rao, Rajesh P. N.; Ojemann, Jeffrey G.; Darvas, Felix

    2016-01-01

    A motor cortex-based brain-computer interface (BCI) creates a novel real world output directly from cortical activity. Use of a BCI has been demonstrated to be a learned skill that involves recruitment of neural populations that are directly linked to BCI control as well as those that are not. The nature of interactions between these populations, however, remains largely unknown. Here, we employed a data-driven approach to assess the interaction between both local and remote cortical areas during the use of an electrocorticographic BCI, a method which allows direct sampling of cortical surface potentials. Comparing the area controlling the BCI with remote areas, we evaluated relationships between the amplitude envelopes of band limited powers as well as non-linear phase-phase interactions. We found amplitude-amplitude interactions in the high gamma (HG, 70–150 Hz) range that were primarily located in the posterior portion of the frontal lobe, near the controlling site, and non-linear phase-phase interactions involving multiple frequencies (cross-frequency coupling between 8–11 Hz and 70–90 Hz) taking place over larger cortical distances. Further, strength of the amplitude-amplitude interactions decreased with time, whereas the phase-phase interactions did not. These findings suggest multiple modes of cortical communication taking place during BCI use that are specialized for function and depend on interaction distance. PMID:27541829

  18. Real-time prediction of hand trajectory by ensembles of cortical neurons in primates

    NASA Astrophysics Data System (ADS)

    Wessberg, Johan; Stambaugh, Christopher R.; Kralik, Jerald D.; Beck, Pamela D.; Laubach, Mark; Chapin, John K.; Kim, Jung; Biggs, S. James; Srinivasan, Mandayam A.; Nicolelis, Miguel A. L.

    2000-11-01

    Signals derived from the rat motor cortex can be used for controlling one-dimensional movements of a robot arm. It remains unknown, however, whether real-time processing of cortical signals can be employed to reproduce, in a robotic device, the kind of complex arm movements used by primates to reach objects in space. Here we recorded the simultaneous activity of large populations of neurons, distributed in the premotor, primary motor and posterior parietal cortical areas, as non-human primates performed two distinct motor tasks. Accurate real-time predictions of one- and three-dimensional arm movement trajectories were obtained by applying both linear and nonlinear algorithms to cortical neuronal ensemble activity recorded from each animal. In addition, cortically derived signals were successfully used for real-time control of robotic devices, both locally and through the Internet. These results suggest that long-term control of complex prosthetic robot arm movements can be achieved by simple real-time transformations of neuronal population signals derived from multiple cortical areas in primates.

  19. Distinct activated cortical areas and volumes in Uygur-Chinese bilinguals

    PubMed Central

    Jiang, Mei; Yang, Li-Xia; Jia, Lin; Shi, Xin; Wang, Hong; Wang, Lin-yun; Abaydulla, Yari; Zhu, Li-Na; Jia, Wen-Xiao

    2015-01-01

    Objective The aim of this study is to evaluate variations in cortical activation in early and late Uygur-Chinese bilinguals from the Xinjiang Uygur Autonomous Region of China. Methodology: During a semantic judgment task with visual stimulation by a single Chinese or Uygur word, functional magnetic resonance imaging (fMRI) was performed. The fMRI data regarding activated cortical areas and volumes by both languages were analyzed. Results The first language (L1) and second language (L2) activated language-related hemispheric regions, including the left inferior frontal and parietal cortices, and L1 specifically activated the left middle temporal gyrus. For both L1 and L2, cortical activation was greater in the left hemisphere, and there was no significant difference in the lateralization index (LI) between the two languages (p > 0.05). Although the total activated cortical areas were larger in early than late bilinguals, the activation volumes were not significantly different. Conclusion Activated brains areas in early and late fluent bilinguals largely overlapped. However, these areas were more scattered upon presentation of L2 than L1, and L1 had a more specific pattern of activation than L2. For both languages, the left hemisphere was dominant. We found that L2 proficiency level rather than age of acquisition had a greater influence on which brain areas were activated with semantic processing. PMID:28123807

  20. Parallel prefrontal pathways reach distinct excitatory and inhibitory systems in memory-related rhinal cortices

    PubMed Central

    Bunce, Jamie G.; Zikopoulos, Basilis; Feinberg, Marcia; Barbas, Helen

    2013-01-01

    To investigate how prefrontal cortices impinge on medial temporal cortices we labeled pathways from the anterior cingulate cortex (ACC) and posterior orbitofrontal cortex (pOFC) in rhesus monkeys to compare their relationship with excitatory and inhibitory sys