Consciousness Flashcards
Try and define consciousness
Subject experience of the mind and the world around us
the 1st person perspective
Being aware and responsive to surroundings
What 2 axis do you use to differentiate (plot) states of conciousness?
X-axis -Vigilance, Wakefulness (open eyes, etc)-vegetative high on that (eyes open), coma very low
Y-axis - Awareness, content of conciousness -vegetative very low on that. Coma too. But locked in syndrome high. REM sleep pretty high
What are the mechanisms of conciousness? Define integration and differentiation
the RAS system is necessary but isnt it (just activates it)
No specific brain region-(no are). thalamo-cortical system important
What matters? Location of neurons? Number of neurons? probably their dynamics-the way their interact over time
Often defined with integration (activity over time is correlation-combine experiences-unification) and differentiation (If all neurons acts together-than no variance-need brain regions to be doing different things)
Some tests use the complexity (differentiation) to measure levels of conciousness after magnetic stimuli-non complex when conciousness is lost-more complex when concious (like Locked in syndrome)-PCI (perturbed complex index)
Describe Coma, Vegetative state and MCS
Coma-eyes closes, not concious, nothing
VS-eyes can be open etc but no awarness
MCV-arousal (eyes can open and stuff) but more awarness than VS
What is covert awarness?
Awarness but cant be seen by the bedside –in people with altered conciousness sometimes they cant show it-use fMRI and see that their brain can do (thinking of tennis for yes, thinking of moving for No) -some patients had no overt awarness, but no covert
What is neglect in terms of conciousness?
rare syndrome-removal from perception of certain systems, sensations, or concept
Like remove the concept of left side, or of your body
not blind but just inst aware of it
How does EEG vary in consciousness?
EEG just look like wiggly line Delta waves-up to 4Hz-sleep Theta-4-8Hz alpha-8-13Hz -healthy brain, closed eyes Beta-13-30Hz -awake, woke Higher frequency neural oscillations (gamma ~40Hz is very high) Slowing-by default bad Alpha rythm-healthy brain-loss is bad
Clinically useful in epilepsy.
Sleep gets EEG slower (except in REM-thats close to awake)
WHat is the GCS
Glasgow coma scale-
Dead people get 3
Mainly tests Eye open (open to not), Verbal response (from yes to no), Motor response (much more tricky-end points are flexion or extension of arm (extensor is 2, flexion 3)
What are the 2 categories of causes of coma?
metabolic-drug overdose, hypoglyceamia, etc
OR
Diffuse Intracranial-head injury (usually more heammorhagic strokes-compression), meningitis, SAH, encephelitis, epilepsy, hypoxic brain injury
Recall characteritics of extradural haemorghage? and subdural?
What is a diffuse axonal injury?
Extra-delayed-lose consiousness, then fine, then lose again
Subdural-banana shape, immediate happening
Diffuse axonal injury-damage of the axons connecting the lobes-the bleeding when moving can damage it -kills communication between parts of brain (like corpus collosum)
