Nature Vol. 16, 4/15, P214 Flashcards
Brain state
A reliable pattern of activity and/or connectivity in multiple large-scale brain networks
Sperduti, M. Et al. A neurocognitive model of meditation based on activation likelihood estimation meta-analysis. Consciousness and Cognition 21, 269-276 (2012)
Three areas showed clusters of activity:
The caudate - disengagement from irrelevant stimuli allowing meditative state
Parahippocampus - control stream of thought and maybe stop mind wandering
Medial PFC - support enhanced self awareness in meditation
- thought to be core cognitive network in experienced meditators
Three components of attention
Alerting - readiness in preparation of an impending task
Orienting- selecting specific information from multiple sensory inputs
Conflict monitoring- monitoring and resolving conflict between computation in different networks; executive attention
Attention Network Test ( ANT)
Test using an arrow pointing left or right and distractions. Quantified efficiency in the 3 components of attention.
Alerting
Component of attention involving noradrenergis system ( locus coeruleus)
Orienting
Component of attention involving frontal and parietal areas: frontal eye fields, inferior and superior parietal lobe
Conflict monitoring
Component of attention involving the executive network for attention which include the ACC, anterior insula and basal ganglia
Anterior Cingulate Cortex
vmPFC
Enables executive attention and control by detecting the presence of conflict emerging from incompatible streams of information processing.
Brain region to which the effects of mindfulness training on attention is most consistently linked in structural and fMRI studies.
ACC
(Also dlPFC) J Neuroscience 32 15601-10 (2012)
(also putamen) decreased grey matter loss, increased sustained attention
Neurobiology of Aging 28, 1623-27(2010)
Emotional regulation
Strategies that can influence which emotions arise and when, how long they occur and how these emotions are experienced and expressed
Mindfulness based emotional regulation may include:
Attention deployment: attending to mental processes, including emotions (present moment awareness)
Cognitive change: changing typical patterns of appraisal of one’s emotions
Response modulation: decreasing tonic levels of suppression (or over-expression?) (non-judgmental acceptance)
Brain regions activated in mindfulness meditation beginners
Lateral PFC and parietal cortex (attentional control and mental effort)
Brain regions active in experienced mindfulness meditation
PFC-parietal often gone.
ACC, striatum and insula remain (decreased need for effort?)
Down regulated connectivity with MB meditation
Emotional regulation
Two studies:
Executive-pain processing
Executive- craving related
Positive connectivity with executive function in MB meditation
Frontal-amygdaloid
Not suppression, but better Mobutu. Might be unique signature of mindful emotional regulation
Default mode network
Believed to be involved in self-referential processing.
mPFC, PCC, anterior precuneus, inferior parietal lobe
High activity during rest, mind-wandering and stimulus independent thought
Insula in meditation
Stronger activation in compassion meditation and after mindfulness training.
Greater cortical thickness in experienced meditators
May represent increased present moment awareness
Shift of self-referential processing to more self-detached
Uncoupling right insula from mPFC while strengthening connection to dlPFC (after mindfulness training)
Areas of the brain showing most consistent change on structural and fMRI (longitudinal randomized control studies and meta-analyses(
ACC PFC PCC insula Striatum- caudate and puts men Amygdala
Brain areas vulnerable to stress-induced brain plasticity
PFC
Hippocampus
Amygdala
Associated with fear-related memories and self-regulatory behavior
Chronic stress induces less flexibility of attention shifting in rats and adult humans
Reduced apical dendritic arborization in raT ACC and fewer feedforward PFC connections
Recovered when stressor removed
Effects on brain of moderate to severe stress
Increase amygdala volume
Decrease PFC and hippocampus volume
Mindfulness training enhance gray matter density in hippocampus and associated reduction in reported stress correlates with decreased amygdala gray matter density
(But is change related to M meditation or increased parasympathetic activity?)
Extinction via exposure
vmPFC (ACC) - recalls the extinction (also executive monitor of disparate info - settles discrepancy?)
Hippocampus- signals contextual safety
Amygdala- acquisition and expression of conditioned fear
Blood-oxygen-level-dependent contrasts (BOLD)
Signals that can be extracted with fMRI and that reflect the change on the amount of deoxyhemoglobin that is induced by changes in the activity of neurons and their synapses in a region of the brain. The signals reflect the activity in a local brain region.
Arterial Spin Labeling (ASL)
An MRI technique that is capable of measuring cerebral blood flow in vivo. It provides cerebral profusion maps without requiring the administration of a contrast agent or the use of ionizing radiation because it uses magnetically labeled endogenous blood water as a freely diffusible tracer.
Fractional anisotropic
A parameter in diffusion tensor imaging, which images brain structures by measuring the diffusion properties of water molecules. It provides information about the microstructural integrity of white matter.
Axial and radial diffusivity
Derived from the eigenvalues of the diffusion tensor, their underlying biophysical properties are associated with axonal density and myelination, respectively.
Activation likelihood estimation meta-analysis
A technique for coordinate-based meta-analysis of neuroimaging data. It determines the convergence of foci reported from different experiments, weighted by the number of participants in each study.
Brain regions noted by ALEMA to be altered in meditators (not while meditating)
1) fronto-polar cortex- meta-awareness?
2,3) sensory cortex and insula- body awareness
4) hippocampus- memory processes
5,6,7) ACC, mid-cingulate cortex, orbitofrontal cortex- self and emotional regulation
8) superior longitudinal fasciculus, corpus callosum- Intra and inter hemisphere communication
Stages of mindfulness meditation practice
Early- effortful doing
Middle/intermediate- effort to reduce mind wandering
Advanced - effortless being
