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Flashcards in Brain Arousal Systems Deck (30):
1

what are the 2 parts of consciousness

1) arousal (being awake)
2) awareness (conscious processing of inputs, etc...)

2

coma

neither awake or aware

3

persistent vegetative state

physciologically identifiable wake/sleep cycles
no evidence of awareness

4

minimally conscious stae

sleep/wake
reproducible evidence of awareness-ability to respond to simple commands

5

disruptions of consciousness result from smaller lesions in ___ ____ or ____

upper brain stem
midrain (diencephalon)
midbrain and hypothalamus

6

both arousal and awareness require activation of the ___

cortex

7

arousal systems using the EAA

RAS
parabrachial nuclei

8

where is the RAS

mid-ventral portion of medulla and midbrain

9

inputs to RAS system from what

all ascending sensory tracts
visual
auditory
trigeminal

10

ther is sufficient synaptic convergence of input to neurons of the RAS that what is lost

modal specificity
-brain knows something is happening, just not what has happened

11

2 pathways of RAS
1) ___ and nucleus

1) dorsal pathway
-neurons synapse on non specific nuclei of thalamus including intralaminar nucleus of the thalamus

from there they diffuse to cortex

2) ventral via basal forebrain and hypothalamus
-bypass thalamus and go to cortical neurons

12

the outputs of parabrachial nuclei are likely exclusively via the ____ _____

ventral pathway

13

within the RAS there is a substantial number of ____ that release ____
-RAS also has population that releases __

interneurons, GABA (regulation)
Ach

14

EAA system provides what for cortical activity

baseline excitation that is cruscial for cortical activity
-get at least to point of sleep/wake cycles

15

arousal system: PPT/LDT

similar to RAS in that receives all sorts of sensory info and has dorsal and ventral pathway
-major NT used is ACETYLCHOLINE

16

role of PPT/LDT

baseline excitation of cortical activity

17

what can damage to the PPN/LDT cause, how prevelant?

produce severe cognitive deficits associated with generalized slowing of cortical processes
-too specific, very rare

18

noradrenergic input from what area
-vital for what?

locus ceruleus
awareness

19

outputs from the locus ceruleus are both ___ and ____

ascending and descending

20

ascending output from LC
(to cortex)
-specific name of one

dorsal and ventral with RAS
-ascending fibers from this group become the dorsal noradrenergic bundle

21

the LC is ___ to the parabrachial nucleus

medial

22

functions of the LC Noradrenergic system

startle and alerting (responses on EEG, reflects norep going up and activating cortical neurons)

sleep-wake

behavioral vigilance

23

serotongeric nuclei?
outputs for what and what paths

raphe nuclei
arousal
both dorsal and ventral paths used

24

serotongeric function

quiet awareness
mood and affect
modulation of pain

25

dopaminergic nuclei and functions

Ventral tegmental area
input for:

cognitive functions
motor activity
emotion

26

thalamic arousal systems, neurons with EAA input interact with ____ that release ___ to create oscillations on EEG

intracortical neurons that release GABA
-thalmacortical neurons
-level of control

27

in persistent vegetative state rostral regions of pons/midbrain/thalamus show neuronal loss that exceeds that of cortex. Cortical neurons are ____-___ mV ____ relative to threshold

10-30 mV hyperpolarized

28

in alzheimer's disease which system is hard hit

cholinergic

29

in limited number of people in persistent vegetative state, treatment with ___ has produced dramatic increase in cognitive function

levodopa

30

during sleep the ____ neurons are hyperpolarized and show occasional bursts
what does this do

thalamocortical neurons
-cuts the cortex off from excitatory influence during deepestt levels of sleep