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On the perturbational complexity index - Coggle Diagram
On the perturbational complexity index
Introduction
Objective measure
quantification of consciousness
Sensitivity to consciousness
consciousness meter
first steps, inspirtions, massemmini
Oweb Monti, command following, purposeful behavioutr
integrity of the neuromuscular system
bridging principles
large scale response dynamics
input-output relationships
uws, minimally conscious state
fully disconnected, input-output disconnection
low sensitivities for this techniques
cognitive task:
even verbally recovered: memor y, concentration, attention, motivation
bypassing
requires input - understand process sensory information
consciousness can be generated from within
lack of options, prevent brain death, what does it feel like
artifacts of modern medicine
theoretical foundation (grounded) + practical use
indepndent of sensory processing and motor behaviour
neural correlates and neural substrates
Discussion
Advantage: quantification on a continuum
Disadvantages: Variability between stimulation sites?
Availability
Sensitivity
Cost
Further Research
Psychedelic state?
posterior hotzone
vs alternatives: brain metabolism, cerebral perfusion
detecting vs communicating
ethical considerations
pain medication in minimally conscious states
low sensitivites
detached from input output
correlational measure
recovery of brain ativity not necessarily needed (also brain metabolsim)
dissociation: decrease in activity during seizures, not based on activity, or metabilic rate
synchrony dissocation - seizures
spectral features, entropy : paradoxes
do not work in all cases
not necisarrily on scalp
contrast with empirical findings
sensitivity and specificity
too many exceptions
adavantage: sensitivity to minimally conscious state
therapeutic potential - building up capapcity
different things at different times
circularity: no independent evidence to subjective reports
calibration of measure
no report, immediate report, delayed report
sensitivity and specificity 100%
detection rates - brain derived fmri active paradigm - 3, p300 erp - 30% - eeg - söow wave alpha delta - 60%, PCI - only 2 out of 38 missed - sensitivity - 94,7 % - perturbing is mroe than observing
retained capacity that has been missed by focusing on overt
input-output behaviour
appalic syndrome
assume there is a physical substrate that is cabable of consciousness until proven otherwise
resore functional external communication or restore complexity
cut-off values, benchmark poulation validation
corroborated by intracranial data
complexitiy recovery, local physiological mechnaisms, low complexity state - pharmacological interventions
cortical deafferentiation
coarse measurement, only a flavour of phi
relative changes not absolute
across subjects as well as within subjects
calibration - exhaustive measure, rel measure
confounding factors in ROC curves - forgot to have been cosncious - ground truth that you trust - best: own experience, subjective reports
Methods
EEG vs hdEEG
TMS
Algorithmic Compression
integration
differentiation
differences in what is exactly measured
algorithmic complexity
sensory stimulation: resting vs stim no diff -
adaptation
automatic processing vs conscious perception
risk of a purely stimulation based procedure
attention praradigms stronger, vs just passive stim, better to involve sub in task, boost cognitive
neural sign - sign for command following - cognitive task
global vs stereotypical - capture
causal interactions vs temporal correlation
intrinsically integrated information
knock on cortex, record the echo
approximates cortico-cortical interactions/potentials
escape the input output chain
source modelling
determinsitic activity
central gravity still there
determinisitc patterns, binarize
joint presence as an important criterium
benchmark to derive a cutoff
benchmark population
roc analysis
causal trace
different perturbations = different reposnes
Results
sleep
activity as high as in wakefullness
aneasthisia
propofol midazolam ketamine
disorders of consciousness + locked in syndrome
stimulate left over cortex islands with neuronavigation
set of altered states of consciousness
ketamine - hallucinations - model of full disconnection and conscousness
xenon
response in VS - sleep like (provided no complete death of neurons)
aphalic syndrome
IIT
start from phenomenology, then go to the brain
balance btw unity and diversity
modular vs full connection
optimization - functional differnetiation and integration
so far dimensions have not been combined , phase
difference: coherence - observing vs perturbing
Mechanims
why does complexity collapse
nobody is cutting the snapses - physiological state no one is cutting the synapses
functional change in how neurons are working
neuronal bistability
anatomical structure is the same
stochstical continuation of activity
content vs complexity
system property
make up and confabulate
step wise distillation
local global - bekenschtein - distraction