Frequent lucid dreaming associated with increased functional connectivity between frontopolar cortex and temporoparietal association areas
Introduction
Definition of Lucid Dreaming
a special sort of dream in which you know that
you are dreaming while still in the dream
during lucid dreams
metacognitive awareness of one’s state of consciousness
regain episodic memory for waking life
variation in lucid dream frequency, ranging
the question of whether the frequency of lucid dreams is related to individual differences in anatomical or functional properties of the brain
Hypoactivity of The prefrontal cortex, parietal cortex and lateral middle temporal cortex
underlie the diminished self-awareness and volitional control during dreaming
increased BOLD signal during lucid dream
aPFC, IPL, precuneus and ITG/MTG
no group-level fMRI
evidence linking frontopolar and parietal regions to lucid dreaming is consistent with the role of these regions in metacognitive functions
further support of a connection between the metacognitive functions of aPFC and lucid dreaming
frontopolar cortex (BA9/10)
increased gray matter volume
increased BOLD activation
to test whether differences in brain structure and/or functional connectivity are associated with frequent lucid dreams while also controlling for dream recall frequency
participants
28 right-handed participants (18 females, age = 22.6 ± 5.4 (mean ± SD), range 18–34)
frequent lucid dream group
control
a minimum of 3–4 lucid dreams per week, or approximately one lucid dream every other night without engaging in training to have lucid dreams
the same age (date of birth <12 months apart), the same gender, a similar level of dream recall and lucid dream frequency of 1 per year or less
問卷
dream recall (0-15pt)
dream frequency (0-15pt)
口試
the number of lucid dreams they had in the last 6m
the most lucid dreams they had ever had in a six-month period
training or not
dream recall
3pt內
dream recall frequency 差異在1-2個夢
Behavioral and questionnaire assessment
association of lucid dreaming and PFC function
working memory capacity
trait mindfulness
prospective and retrospective memory
operation span task (OSpan)
rotation span task (RotSpan)
symmetry span task (SymSpan)
to-be-remembered stimuli are letters
unrelated task is verifying the accuracy of an equation
locations of red squares in a 4 × 4 grid
verifying the vertical symmetry of an image
arrows pointing in one of eight different directions
whether a rotated letter is presented correctly
Toronto Mindfulness Scale
Curiosity
Decentering
an attitude of wanting to learn more about one’s experiences
awareness of one’s experience with some distance and dis-identification rather than being carried away by one’s thoughts and feelings
Prospective and Retrospective Memory Questionnaire (PRMQ)
Mind-wandering frequency
Daydreaming Frequency subscale of the Imaginal Process Inventory (IPI)
experience daydreaming in their daily life with reference to a five-point Likert-scale, ranging from “A” to “E.”
measures self-report scores of the frequency of both prospective and retrospective memory errors in everyday life
均無顯著差異
Voxel-based morphometry
a voxel-wise comparison of local tissue volumes within a group or across groups
No significant differences in gray matter density were observed for ROIs
Voxel intensities represents the relative volume at that voxel
left & right prefrontal cortex
left or right hippocampus
total hippocampus
by reference
Seed-based whole-brain resting-state functional connectivity
To estimate connectivity
Based on the time series of a seed voxel (or ROI), connectivity is calculated as the correlation of time series for all other voxels in the brain.
brain areas with similar activity patterns are likely to be communicating and sharing information.
the frequent lucid dream group showed significantly increased functional connectivity between left aPFC and five clusters
the left and right inferior parietal lobule (IPL)
left and right middle temporal gyrus (MTG)
right inferior frontal gyrus (IFG)
reduced functional connectivity
bilateral insula
other regions identified in ref. 9 to increase BOLD signal during lucid REM sleep
frequent lucid dream group showed increased connectivity
left IPL and left MTG, right lingual gyrus
right IPL and left aPFC, right PCC
right MTG and left aPFC, left MFG
decreased connectivity
right IPL and right MFG, left insula
left precentral gyrus and left SMC
IPL/IPS subdivision analysis
to characterize the overlap between these clusters and anatomical subdivisions of the angular gyrus (PGa/ PGp) and intra-parietal sulcus (hlP1, hlP2 and hlP3)
The subdivisions of AG and IPS have been shown to have distinct structural and functional connectivity patterns
Frequent lucid dreamers showed significantly increased mean functional connectivity
left aPFC and left PGa
right PGa and right hlP1
PGa
PGp
hIP1
hIP2
hIP3
basal ganglia
ventral premotor areas
ventrolateral prefrontal cortex
ventromedial prefrontal cortex
posterior cingulate
hippocampus-regions comprising the default mode network.
ventral premotor
ventral premotor
middle frontal gyrus
middle frontal gyrus
insula
extrastriate visual areas
Large-scale networks (LSNs) analysis
compare whether connectivity within and between established large scale resting-state brain networks showed differences between groups
7 systems
default mode network
cingulo-opercular
frontoparietal control network
salience network
ventral attention network
dorsal attention network
visual system
evaluating the connectivity between all nodes within the frontoparietal control subsystem that showed the largest overlap with the functional connectivity results, based on a 400 node parcellation of the 17 functional network
within any LSN between groups
between-network connectivity between groups
no differences
no differences
connectivity within the FPCN subsystem between groups
no differences
Whole-brain graph-theoretic analysis
To evaluate whole-brain differences in network and topological properties
degree (k)
strength (s)
betweenness centrality (BC)
eigenvector centrality (EC)
total number of connections of a node
the sum of the weights of all connections to a node
the length between nodes
fraction of all shortest paths in the network that contain a given node
nodes connected to other densely connected nodes as having high centrality
connection density (δ)
the number of existing connections over the total number of possible connections
frequent lucid dream group is higher
frequent lucid dream group is higher
No differences
No differences
more closely linked to the semantic system than PGp
higher-order thinking that enables understanding, analysis, and control of one’s cognitive processes, especially when engaged in learning.
hIP2 and hIP1) may support more complex aspects of numerical and mathematical information processing
舉例
了解清醒夢的定義