Reducing signal loss of the parahippocampal gyrus improves imaging of the default-mode network in 3.0-T MRI: the effect of susceptibility-induced field gradients

2015 ◽  
Vol 28 (12) ◽  
pp. 1739-1746
Author(s):  
Yu-Sheng Tseng ◽  
Teng-Yi Huang ◽  
Shang-Yueh Tsai
Keyword(s):  
Default Mode Network ◽  
Parahippocampal Gyrus ◽  
Signal Loss ◽  
Default Mode ◽  
Field Gradients ◽  
Induced Field ◽  
3.0 T ◽  
3.0 T Mri

scholarly journals Medial prefrontal decoupling from the default mode network benefits memory

2019 ◽  
Author(s):  
N.C.J. Müller ◽  
M. Dresler ◽  
G. Janzen ◽  
C.F. Beckmann ◽  
G Fernández ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Default Mode Network ◽  
Memory Performance ◽  
Task Demands ◽  
Parahippocampal Gyrus ◽  
Developmental Study ◽  
Cross Sectional ◽  
Memory Processing ◽  
Default Mode ◽  
New Material

AbstractIn the last few years the involvement of the medial prefrontal cortex (mPFC) in memory processing has received increased attention. It is centrally involved when we use prior knowledge (schemas) to improve learning of new material. With the mPFC also being one of the core hubs of the default mode network (DMN) and the DMN’s role in memory retrieval, we decided to investigate whether the mPFC in a schema paradigm acts independently of the DMN. We tested this with data from a cross-sectional developmental study. During retrieval of schema items, the mPFC decoupled from the DMN with the degree of decoupling predicting memory performance. This finding suggests that a demand specific reconfiguration of the DMN supports schema memory. Additionally, we found that in the control condition, which relied on episodic memory, activity in the parahippocampal gyrus was positively related to memory performance. We interpret these results as a demand specific network reconfiguration of the DMN: a decoupling of the mPFC to support schema memory and a decoupling of the parahippocampal gyrus facilitating episodic memory. This supports the notion of dynamic reconfiguration of brain networks in response to task demands in the sense of process specific alliances.

scholarly journals Resting state functional coupling between the ascending synchronising system, limbic system and the default mode network via theta oscillations

2016 ◽  
Author(s):  
Parnesh Raniga ◽  
Bryan Paton ◽  
Gary F. Egan
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Default Mode Network ◽  
Resting State ◽  
Theta Oscillations ◽  
Parahippocampal Gyrus ◽  
Functional Coupling ◽  
Resonance Imaging ◽  
Default Mode

AbstractIn order to better understand dysfunction in dementia and psychiatric illnesses, the underlying neuronal systems that give rise to normal memory and cognitive processes need to be better understood. Based on electrophysiological recordings in animals, theta oscillations have been proposed as an intrinsic mechanism for the orchestration of memory functions, especially episodic and autobiographical memory. Theta oscillations are controlled by the ascending synchronising system, a set of nucleui in the pontine tegmentum and basal forebrain. At a network level, the default mode network has been shown to be responsible for episodic and autobiographical.Using resting state fMRI data, we show using an ICA approach, seed based connectivity and dynamic causal modelling that the ascending synchronising system is coupled to the medial temporal lobe nodes including the hippocampus and parahippocampal gyrus and with the default mode network. Our results provide thus support the role of theta oscillations in memory function and coordination at a network level.HighlightsResting state functional coupling between the DMN, MTL and ascending synchronising system.Theta oscillations may be the basis of this coupling given the role of these structures in control of theta.Theta oscillations have been implicated in memory, cognition and predictive coding.DMN, MTL and ASS are implicated in Alzheimer’s disease.AbbreviationsMRIMagnetic resonance imagingfMRIfunctional magnetic resonance imagingrs-fmriresting state functional magnetic resonance imagingPnOPontine nucleus oralisSuMSupra-mamillary nucleus.MSMedial septumDBDiagonal band of Broca.VTAventral tegmental areaPCCPosterior cingulate cortexHCHippocampusARASAscending reticular activating systemASSAscending synchronising systemDMNDefault Mode NetworkaMPFCAnterior Medial Prefrontal CortexpIPLPosterior inferior parietal lobuleNBMNucleus Basalis MynertDCMDynamic causal modellingPHGParahippocampal Gyrus

scholarly journals Diminished default mode network recruitment of the hippocampus and parahippocampus in temporal lobe epilepsy

2013 ◽  
Vol 119 (2) ◽  
pp. 288-300 ◽  
Author(s):  
G. Andrew James ◽  
Shanti Prakash Tripathi ◽  
Jeffrey G. Ojemann ◽  
Robert E. Gross ◽  
Daniel L. Drane
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Default Mode Network ◽  
Resting State ◽  
Functional Neuroimaging ◽  
Parahippocampal Gyrus ◽  
Epileptogenic Focus ◽  
Data Set ◽  
Default Mode

Object Functional neuroimaging has shown that the brain organizes into several independent networks of spontaneously coactivated regions during wakeful rest (resting state). Previous research has suggested that 1 such network, the default mode network (DMN), shows diminished recruitment of the hippocampus with temporal lobe epilepsy (TLE). This work seeks to elucidate how hippocampal recruitment into the DMN varies by hemisphere of epileptogenic focus. Methods The authors addressed this issue using functional MRI to assess resting-state DMN connectivity in 38 participants (23 control participants, 7 patients with TLE and left-sided epileptogenic foci, and 8 patients with TLE and right-sided foci). Independent component analysis was conducted to identify resting-state brain networks from control participants' data. The DMN was identified and deconstructed into its individual regions of interest (ROIs). The functional connectivity of these ROIs was analyzed both by hemisphere (left vs right) and by laterality to the epileptogenic focus (ipsilateral vs contralateral). Results This attempt to replicate previously published methods with this data set showed that patients with left-sided TLE had reduced connectivity between the posterior cingulate (PCC) and both the left (p = 0.012) and right (p < 0.002) hippocampus, while patients with right-sided TLE showed reduced connectivity between the PCC and right hippocampus (p < 0.004). After recoding ROIs by laterality, significantly diminished functional connectivity was observed between the PCC and hippocampus of both hemispheres (ipsilateral hippocampus, p < 0.001; contralateral hippocampus, p = 0.017) in patients with TLE compared with control participants. Regression analyses showed the reduced DMN recruitment of the ipsilateral hippocampus and parahippocampal gyrus (PHG) to be independent of clinical variables including hippocampal sclerosis, seizure frequency, and duration of illness. The graph theory metric of strength (or mean absolute correlation) showed significantly reduced connectivity of the ipsilateral hippocampus and ipsilateral PHG in patients with TLE compared with controls (hippocampus: p = 0.028; PHG: p = 0.021, after correction for false discovery rate). Finally, these hemispheric asymmetries in strength were observed in patients with TLE that corresponded to hemisphere of epileptogenic focus; 87% of patients with TLE had weaker ipsilateral hippocampus strength (compared with the contralateral hippocampus), and 80% of patients had weaker ipsilateral PHG strength. Conclusions This study demonstrated that recoding brain regions by the laterality to their epileptogenic focus increases the power of statistical approaches for finding interhemispheric differences in brain function. Using this approach, the authors showed TLE to selectively diminish connectivity of the hippocampus and parahippocampus in the hemisphere of the epileptogenic focus. This approach may prove to be a useful method for determining the seizure onset zone with TLE, and could be broadly applied to other neurological disorders with a lateralized onset.

Increased Default Mode Network Connectivity Following EEG Neurofeedback in PTSD

2012 ◽  
Author(s):  
Rosemarie Kluetsch ◽  
Tomas Ros ◽  
Jean Theberge ◽  
Paul Frewen ◽  
Christian Schmahl ◽  
...  
Keyword(s):  
Default Mode Network ◽  
Network Connectivity ◽  
Default Mode ◽  
Eeg Neurofeedback

Default mode network connections supporting intra-individual variability in typically developing primary school children: An EEG study.

2020 ◽  
Vol 34 (7) ◽  
pp. 811-823
Author(s):  
Evgeniya Yu. Privodnova ◽  
Helena R. Slobodskaya ◽  
Andrey V. Bocharov ◽  
Alexander E. Saprigyn ◽  
Gennady G. Knyazev
Keyword(s):  
Primary School ◽  
School Children ◽  
Default Mode Network ◽  
Individual Variability ◽  
Primary School Children ◽  
Typically Developing ◽  
Default Mode ◽  
Network Connections

The 1000Plus study protocol – a prospective observational study on the mismatch concept in a 3.0 T MRI

2009 ◽  
Vol 36 (S 02) ◽  
Author(s):  
B Hotter ◽  
S Pittl ◽  
M Ebinger ◽  
G Oepen ◽  
K Jegzentis ◽  
...  
Keyword(s):  
Observational Study ◽  
Study Protocol ◽  
Prospective Observational Study ◽  
3.0 T ◽  
3.0 T Mri

Frequency domains of resting state default mode network activity in schizophrenia

2014 ◽  
Vol 45 (01) ◽  
Author(s):  
G Mingoia ◽  
K Langbein ◽  
M Dietzek ◽  
G Wagner ◽  
S Smesny ◽  
...  
Keyword(s):  
Default Mode Network ◽  
Resting State ◽  
Network Activity ◽  
Default Mode ◽  
Frequency Domains

Endoscopic Endonasal Pituitary Adenoma Resection with Intraoperative 3.0 T MRI Scanning

Skull Base ◽  
2009 ◽  
Vol 19 (01) ◽  
Author(s):  
David Netuka ◽  
Vaclav Masopust ◽  
Tomas Belsan ◽  
Vladimir Beneš
Keyword(s):  
Pituitary Adenoma ◽  
Endoscopic Endonasal ◽  
3.0 T ◽  
3.0 T Mri
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