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Flashcards in Phys - Brain Arousal Systems Deck (38)
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1

describe coma

neither awake or aware
- no sleep/wake cycles
- EEG waves normally abnormal

2

describe persistent vegetative state

physiologically identifiable sleep/wake cycles
- no evidence of awareness
- EEG may or may not be abnormal
(the "arousal/wakefulness" level of consciousness)

3

describe minimally conscious state

pt has sleep/wake cycles
- reproducible evidence of awareness; ability to respond to simple commands
- limited or absent communication

4

are disruptions of consciousness usually from damage to cerebral cortex?

it can be, but the damage would have to be massive and bilateral
- more often from smaller lesions in brainstem, midbrain, or hypothalamus

5

what is the reticular activation system (RAS)?
- what tracts use it?

a type of arousal system that uses EAA
- all ascending sensory tracts send info to the RAS

6

where is the RAS located

mid-ventral portion of medulla and midbrain

7

why does the RAS system lose modal specificity?

there is sufficient *synaptic convergence* of input to the neurons of RAS that it loses specificity

8

compare the two pathways of the RAS

dorsal: synapses in intralaminar nucleus of thalamus

ventral: goes through basal forebrain and hypothalamus but NOT the thalamus

9

where are the parabrachial nuclei located

in the pons

10

what inputs go to the parabrachial nuclei?

similar to RAS; all/most of the sensory inputs in the body

11

what pathway do the parabrachial nuclei use

ventral pathway (bypass the thalamus)

12

where in the cortex do the parabrachial nuclei innervate?

diffuse innervation of the entire cortex

13

what is the major NT utilized by both parabrachial nuclei and RAS

EAA/glutamate

14

what other NTs does the RAS release?

GABA
Ach

15

why do the PPT/LDT nuclei lose modal specificity?

they receive so much input that specificity is lost

16

major NT of the PPT/LDT?

Ach

17

outputs from the PPT/LDT use what pathway?

the dorsal (through thalamus) and ventral (bypasses thalamus) pathways

18

damage to the PPT/LDT causes what?

produces severe cognitive deficits that are associated with a generalized slowing of cortical processes
- not coma though

19

transmission of EAA and Ach will get you to what level of the consciousness hierarchy?

from coma --> arousal/wakefulness (persistent vegetative state)

20

what type of system is the locus ceruleus

noradrenergic (produces NE)

21

input from the paragigantocellular nerve in the rostral medulla goes to what brain arousal system, and what kind of info is it

locus ceruleus
- sensory input from all ascending tracts

22

input from the PAG goes to what brain arousal system

locus ceruleus

23

compare incoming information in the locus ceruleus to that in the EAA/Ach systems

info going to the locus ceruleus has undergone more neural processing than the sensory inputs received by EAA/Ach systems

24

describe the pathway of output information from the locus ceruleus

joins axons from RAS/parabrachial/PPT/LDT in the dorsal and ventral pathways to become the dorsal noradrenergic bundle

25

functions of the locus ceruleus noradrenergic system

startle and alerting responses on EEG
- sleep/wake
- behavioral vigilance

26

what is the input information to the raphi nucleus

- sensory from spinal cord
- trigeminal sensory nucleus
- PAG (proprioception)

27

what pathways does output information from raphi nucleus use

dorsal and ventral pathways
(mostly ventral)

28

what is the function of the serotonergic (raphi nucleus) brain arousal system

quiet awareness
- mood and affect
- modulation of pain

29

describe the pathway and NTs from coma to alertness

coma --(EAA/Ach)--> arousal/wakefulness --(NE/5HT)--> awareness --(dopaminergic)--> alertness

30

what arousal system will get you from awareness to full alertness

dopaminergic (ventral tegmental area)