What do lucid dreams mean

During the resting-state scan, participants were instructed to stay awake and relax, to hold as still as possible, and to keep their eyes open. A diffeomorphic non-linear registration algorithm diffeomorphic anatomical registration through exponentiated lie algebra; DARTEL 81 was used to iteratively register the images to their average. The resulting flow fields were combined with an affine spatial transformation to generate Montreal Neurological Institute MNI template spatially normalized and smoothed Jacobian-scaled gray matter images.

We additionally evaluated average gray matter density between groups in the two regions of prefrontal cortex and bilateral hippocampus observed by ref. Total hippocampal volume was also extracted from an updated routine for automated segmentation of the hippocampal subfields implemented in FreeSurfer version 6.

Resting-state fMRI data were processed based on a workflow described previously To remove potential scanner instability effects, the first four volumes of each EPI sequence were removed. Brain mask, cerebrospinal fluid CSF mask and white matter WM mask were parcellated using FreeSurfer 87 , 88 , 89 , 90 and transformed into EPI space and eroded by 2 voxels in each direction to reduce partial volume effects.

Realigned timeseries were masked using the brain mask. Differences in global mean intensity between functional sessions were removed by normalizing the mean of all voxels across each run to This was followed by nuisance regression of motion-related artifacts using a GLM with six rigid-body motion registration parameters and outlier scans as regressors. Principal components of physiological noise were estimated using the CompCor method Timeseries were then denoised using a GLM model with 10 CompCor components as simultaneous nuisance regressors.

Note that global signal regression was not performed because this processing step can induce negative correlations in group-level results Although aPFC functional connectivity was the main target of the current investigation, we also performed supplementary seed-based functional connectivity analysis on other regions identified in ref.

Translated ROIs were restricted within the cortical ribbon mask. Full brain connectivity correlation maps were calculated using AFNI Voxelwise independent samples t -tests were performed between groups. Whole-brain analyses were conducted, correcting for multiple comparisons using topological FDR 93 at the cluster level. Cytoarchitectonic mapping studies have shown that AG can be divided into anterior PGa and posterior PGp subdivisions and IPS can be divided into three distinct subdivisions hlP1 on the posterior lateral bank, hlP2 which is anterior to hIP1, and hlP3 which is posterior and medial to both subdivisions 51 , The subdivisions of AG and IPS have been shown to have distinct structural and functional connectivity patterns We performed a follow-up analysis on the functional clusters identified in our seed based functional connectivity analysis in order to characterize the overlap between these clusters and the anatomical subdivisions of these regions.

MPMs create non-overlapping regions of interest from the inherently overlapping cytoarchitectonic probability maps 94 , The anatomical boundaries of these maps are described in detail in previous publications 51 , 52 , Mean connectivity values from each binarized mask were exacted using the MarsBar toolbox In order to compare whether connectivity within and between established large scale resting-state brain networks showed differences between groups, we extracted timecourses from a set of nodes from a meta-analysis by Power, et al.

For each network, we calculated the mean correlation between all nodes within the network within-network connectivity as well as the mean correlation between all nodes of a given network and all the nodes of each other network between-network connectivity. We also evaluated the overlap between our seed-based functional connectivity results and a network parcellation of human brain connectivity networks We followed up this network overlap analysis by evaluating the connectivity between all nodes within the frontoparietal control subsystem that showed the largest overlap with the functional connectivity results, based on a node parcellation of the 17 functional networks To construct functional networks for graph-theoretic analysis, anatomical scans were segmented using FreeSurfer and parcellated into regions according to the Lausanne atlas included in the connectome mapping toolkit 37 , Resting-state fMRI data pre-processing was identical to the procedures described above see Resting-state fMRI data processing with the exception that no spatial smoothing was applied, as spatial smoothing can distort network measures derived from average timeseries within parcellated regions e.

All network metrics were computed in Matlab v 9. For each node in the network we analyzed the degree k , strength s , betweenness centrality BC and eigenvector centrality EC. These metrics are described in detail elsewhere see refs 98 , 99 for reviews. In brief, k quantifies the total number of connections of a node, while s quantifies the sum of the weights of all connections to a node. BC and EC are different measures of centrality of nodes: BC is the fraction of all shortest paths in the network that contain a given node and EC quantifies nodes connected to other densely connected nodes as having high centrality.

In order to compare network and topological properties between groups it is important to ensure that graphs contain the same number of edges Following recommended practice 99 , rather than apply a single threshold to graphs, which would limit any findings to a single arbitrary connection density, we thresholded graphs over a range of connection densities 0. To test the null hypothesis of no difference in AUC between groups, we used a nonparametric bootstrapping procedure in which we randomly reassigned groups with replacement 10, times and computed a bootstrapped t -value for each node.

This statistical approach has been used in previous studies and allows for strong control over type I error , The data that support the findings of this study are available from the corresponding author on reasonable request. LaBerge, S. Lucid dreaming: The power of being awake and aware in your dreams Jeremy P. Tarcher, Kihlstrom, J. Lucid dreaming: Metaconsciousness during paradoxical sleep in Dream research: Contributions to clinical practice ed.

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Cortex 20 , — Binder, J. Where is the semantic system? A critical review and meta-analysis of functional neuroimaging studies. Cortex 19 , — Windt, J. One example of this is schizophrenia. This condition may cause people to have difficulty distinguishing between hallucinations and real-life events.

In some cases, Dr. Aspy told us, lucid dreaming may actually exacerbate the condition. Other scientists ask whether or not encouraging lucid dreaming might blur the line between sleep-wake psychological boundaries. They call for more research into how it might affect certain vulnerable people, including those who experience dissociation.

Lucid dreaming may be a fascinating, helpful, or pleasant experience, but you should consider why you are interested in achieving it and what you expect to get from it before trying to experiment.

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There is a range of affordable mattresses available to order online. Learn about the best options…. Learn more. Definition The experience Applications Techniques Concerns and risks Have you ever started dreaming and suddenly realized that you were in a dream?

Share on Pinterest What is lucid dreaming, and how can you achieve it? What is lucid dreaming? When does it happen, and what is it like? What are its applications? Share on Pinterest Lucid dreaming may help people get rid of their nightmares and resolve their fears. Techniques for lucid dreaming. Share on Pinterest Text shifts in dreams, so you may become aware that you are dreaming by trying to reread it.

Concerns and risks. Latest news Scientists identify new cause of vascular injury in type 2 diabetes. Adolescent depression: Could school screening help? Related Coverage. Linking sleep disturbance with depression, anxiety, bipolar disorder, schizophrenia Using wrist accelerometers to generate data about sleep, researchers identified associations between sleep properties and mental health conditions.

Two more studies suggest that people who have lucid dreams may be more creative. While these findings are preliminary and more research is needed before any concrete assertion can be made, Dr. Roth says. And dreaming is the process of your brain organizing and placing things. Nightmares, Dr. Roth notes, occur when your brain is trying to organize things in a detrimental way. And one way to help you break that pattern is a treatment called imagery rehearsal therapy.

The patient will then rehearse the dream, rereading the narrative and visualizing it. Some patients, she says, even choose to make their own movies of the rescripted version with their smartphone. But for people interrupting their sleep pattern to induce lucid dreaming, that can lead to sleep deprivation which can affect alertness, memory, stress and even lead to issues like high blood pressure and diabetes.

An expert explains what lucid dreaming is, how to experience them for yourself and if there are health benefits to having lucid dreams. Learn more about vaccine availability. Advertising Policy.