scholarly journals The structure of hippocampal trisynaptic pathway relates to rapid category learning in humans

2021 ◽  
Author(s):  
Margaret L Schlichting ◽  
Melisa Gumus ◽  
Teresa Zhu ◽  
Michael L Mack

Prior work suggests that complementary white matter pathways within the hippocampus differentially support learning of specific versus general information. In particular, while the trisynaptic pathway (TSP) rapidly forms memories for specific experiences, the monosynaptic pathway (MSP) slowly learns generalities. However, despite the theorized significance of such circuitry, characterizing how information flows within hippocampus (HPC) to support learning in humans remains a challenge. We leveraged diffusion-weighted imaging as a proxy for individual differences in TSP and MSP white matter structure and related it to category learning ability. We hypothesized that learning to categorize the "exception" items that deviated from category rules would benefit from TSP-supported mnemonic specificity. Participant-level estimates of TSP and MSP integrity were constructed from HPC subfield connectomes of white matter streamline density. Consistent with theories of TSP-supported learning mechanisms, we found a specific association between TSP integrity and exception learning. These results highlight the significant role of HPC circuitry in complex human learning.

2017 ◽  
Author(s):  
Yaniv Assaf ◽  
Heidi Johansen-Berg ◽  
Michel Thiebaut de Schotten

AbstractDiffusion weighted imaging has further pushed the boundaries of neuroscience by allowing us to peer farther into the white matter microstructure of the living human brain. By doing so, it has provided answers to fundamental neuroscientific questions, launching a new field of research that had been largely inaccessible. We will briefly summarise key questions, that have historically been raised in neuroscience, concerning the brain’s white matter. We will then expand on the benefits of diffusion weighted imaging and its contribution to the fields of brain anatomy, functional models and plasticity. In doing so, this review will highlight the invaluable contribution of diffusion weighted imaging in neuroscience, present its limitations and put forth new challenges for the future generations who may wish to exploit this powerful technology to gain novel insights.


2001 ◽  
Author(s):  
William L. Kelemen ◽  
Catherine E. Creeley
Keyword(s):  

2018 ◽  
Vol 2 (2) ◽  
pp. 84
Author(s):  
Fahrurrrazi Fahrurrrazi

Penelitian ini dilatarbelakangi oleh fenomena minat baca siswa dan pengaruh minat baca terhadap pertumbuhan kemampuan belajar siswa pada jenjang-jenjang pendidikan selanjutnya. Kepala sekolah sebagai lokomotif perkembangan mutu pendidikan memiliki peran strategi bagi pengumbuhan dan pengembangan minat baca peserta didik. Penelitian ini bertujuan untuk mengetahui peran kepala madrasah sebagai edukator, manajer, dan innovator dalam pengembangan minat baca peserta didik di MIT Nurul Islam Kota Semarang. Penelitian ini merupakan penelitian kualitatif lapangan, data dikumpulkan melalui observasi, wawancara, dokumentasi dan triangulasi, serta dianalisis dengan teknik analisis deskriptif. Hasil penelitian ini menunjukkan bahwa: 1) Peran kepala madrasah sebagai edukator dalam pengembangan minat baca peserta didik meliputi meliputi tiga pembinaan, yakni pembinaan mental dan moral, serta pembinaan artistik. 2) Peran kepala madrasah sebagai manajer dalam pengembangan minat baca peserta didik di MIT Nurul Islam meliputi penerapan fungsi-fungsi manajemen dengan didasarkan pada pada kerjasama dengan USAID dan UIN Walisongo Semarang. 3) Peran kepala madrasah sebagai innovator dalam pengembangan minat baca peserta didik di MIT Nurul Islam Kota Semarang meliputi inovasi strategi, pola pikir (mindset) dan struktur. Abstract This research is motivated by the phenomenon of reading interest of students and the influence of reading interest on the growth of students' learning ability in the next level of education. The principal as a locomotive of the development of the quality of education has a strategic role for the growth and development of reading interest of learners. This study aims to determine the role of principal as an educator, manager, and innovator in the development of reading interest of learners in MIT Nurul Islam Semarang City. This research is a qualitative field research, data collected through observation, interview, documentation and triangulation, and analyzed by descriptive analysis technique. The results of this study indicate that: 1) The role of principal as an educator in the development of reading interest of learners includes three activities are coaching, namely mental and moral coaching, and artistic coaching. 2) The role of principal as manager in the development of reading interest of learners at MIT Nurul Islam covers the application of management functions based on cooperation with USAID and UIN Walisongo Semarang. 3) The role of principal as innovator in the development of reading interest of learners at MIT Nurul Islam Semarang City includes innovation strategy, mindset, and structure.


Life ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Ilias Kalafatakis ◽  
Maria Savvaki ◽  
Theodora Velona ◽  
Domna Karagogeos

Demyelinating pathologies comprise of a variety of conditions where either central or peripheral myelin is attacked, resulting in white matter lesions and neurodegeneration. Myelinated axons are organized into molecularly distinct domains, and this segregation is crucial for their proper function. These defined domains are differentially affected at the different stages of demyelination as well as at the lesion and perilesion sites. Among the main players in myelinated axon organization are proteins of the contactin (CNTN) group of the immunoglobulin superfamily (IgSF) of cell adhesion molecules, namely Contactin-1 and Contactin-2 (CNTN1, CNTN2). The two contactins perform their functions through intermolecular interactions, which are crucial for myelinated axon integrity and functionality. In this review, we focus on the implication of these two molecules as well as their interactors in demyelinating pathologies in humans. At first, we describe the organization and function of myelinated axons in the central (CNS) and the peripheral (PNS) nervous system, further analyzing the role of CNTN1 and CNTN2 as well as their interactors in myelination. In the last section, studies showing the correlation of the two contactins with demyelinating pathologies are reviewed, highlighting the importance of these recognition molecules in shaping the function of the nervous system in multiple ways.


Author(s):  
Preeti Mundhada ◽  
Sudarshan Rawat ◽  
Ullas Acharya ◽  
Dhananjay Raje

Abstract Aim To determine the role of diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) values in differentiating benign and malignant orbital masses. Materials and Methods After obtaining institutional ethical board approval and informed consent from all patients, an observational study was done for a period of 24 months in the radiology department of a tertiary care hospital in South India. Conventional magnetic resonance imaging and DWI using a 3T scanner was done for all patients with suspected orbital mass lesion. ADC value and clinicohistopathological correlation were studied for every patient. Chi-square test was used to compare the signal characteristics of DWI and ADC maps between benign and malignant lesions. A comparison of mean ADC values for benign and malignant masses was performed using Student’s t-test for independent samples. The cut-off value for ADC was obtained using the receiver operating characteristic (ROC) curve. Results Of 44 patients with orbital lesions, 70% were benign and 30% were malignant. There was a significant difference in the mean ADC values of benign and malignant orbital masses. Using ROC curve analysis, an optimal ADC threshold of 1.26 × 10−3 mm2/s was calculated for the prediction of malignancy with 100% sensitivity, 80.65% specificity, and 86.36% accuracy (95% confidence interval: 0.872, 1.00, p < 0.0001). Two ADC thresholds were used to characterize the orbital masses with more than 90% confidence. Conclusion Quantitative assessment of ADC is a useful noninvasive diagnostic tool for differentiating benign and malignant orbital masses. Malignant orbital lesions demonstrate significantly lower ADC values as compared with benign lesions.


2021 ◽  
pp. 1-17
Author(s):  
Patrick T. Davies ◽  
Morgan J. Thompson ◽  
Jesse L. Coe ◽  
Melissa L. Sturge-Apple

Abstract This study examined children's duration of attention to negative emotions (i.e., anger, sadness, fear) as a mediator of associations among maternal and paternal unsupportive parenting and children's externalizing symptoms in a sample of 240 mothers, fathers, and their preschool children (Mage = 4.64 years). The multimethod, multi-informant design consisted of three annual measurement occasions. Analysis of maternal and paternal unsupportive parenting as predictors in latent difference changes in children's affect-biased attention and behavior problems indicated that children's attention to negative emotions mediated the specific association between maternal unsupportive parenting and children's subsequent increases in externalizing symptoms. Maternal unsupportive parenting at Wave 1 predicted decreases in children's attention to negative facial expressions of adults from Wave 1 to 2. Reductions in children's attention to negative emotion, in turn, predicted increases in their externalizing symptoms from Wave 1 to 3. Additional tests of children's fearful distress and hostile responses to parental conflict as explanatory mechanisms revealed that increases in children's fearful distress reactivity from Wave 1 to 2 accounted for the association between maternal unsupportive parenting and concomitant decreases in their attention to negative emotions. Results are discussed in the context of information processing models of family adversity and developmental psychopathology.


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