Neuro 18: part 2 Flashcards
Is sleep a consequence or cause of neurological disease
Could be either realy
Definiton of consciousness
the state of being aware of and responsive to one’s surroundings
Elements of conscioussness
Level, content, self
Classify following in terms of VIGILANCE (awake behaviour, eyes open) and AWARENESS (level/content of consciousness…. richness of experience): Coma General anaesthetic Locked in syndrome Veg state Dementia
Coma, very low for both General anaesthesia similar to coma but could have tiny bit more awareness Locked in high awareness and high vigilance (just under conscios) Veg state- high vigilance but very low awareness Dementia/minimally conscious state= fairly normal vigilance, but reduced awareness
Why does RF project to cortex
allowing that sensory signals to reach cortical sites of conscious awareness such frontoparietal cortex
Types of neurotransmitters in the RAS
RAS - RF projects to the hypothalamus, thalamus and the cortex Ventral tegmental Area (dopaminergic neurones)… this relates to reward pathway mesolimbic…. VTA in midbrain pons- Locus coeruleus (noradrenergic neurones)… this relates to pain
t/f consciousness arises from a partcular part of the brain
f.. it emerges as a result of cortico-thalamic transmission
What is important for consciousness
dynamics of neuronal activity– integrated and differentiated
How can consciousness be measured
Give TMS and then meausure activity after with EEG You can measure how well that induced TMS travels across to other brain regions. In an awake individual, this signal will spread across brain regions (high integration) but in asleep will not (low integration) Can also see if the different brain areas to which the signal spreads process the signal differently (i.e. high differentiateion, heterogenous) or in the same way (i.e. low differentiation) Can quantify this to give PCI…. pertubational complexity index (PCI)
What is ‘neural correlates of consciousness’ referring to
The minimum neuronal mechanisms jointly sufficient for any one specific conscious experience. Primarily localized to a posterior cortical hot zone that includes sensory areas (Koch et al., 2016) i.e. where is the brain region that corresponds to a particular experience of consciousness
3 disorders of consciousness
Coma- Absent wakefulness and absent awareness, Vegitative state- Wakefulness but absent awareness Minimally conscious state- wakefulness with minimal awareness
T/F brainstem death is a disorder of consciousness
F… neither is locked in syndrome
Feedforword processing vs top-down recurrent processing
feed forward=subliminal or non sonscious Top dorwn is conscious access We can have top-down and bottom-up processes – there are non-conscious processes that bubble up to conscious access.
State the components of a coma
-can’t be awakened -doesn’t respond norally to painful stimulu, light or sound -Lacks normal sleep wake cycle -Does not initiate voluntary actiond
Which area of brain might be affected in: vegetative state locked in syndrome brainstem death
vegetative state=cortex/hemispheres (intact RAS) locked in syndrome=damage e.g. to ventral pons (motor system)…. intact cortex and intact RAS brainstem death= irremediable damage to brainstem
