Brain Arousal Systems Flashcards
Brain arousal systems affect what?
Sleep disorders Major depression Medical procedures and anesthetics Autism spectrum Coma Fatigue Neuroactive drugs Antihistamines
____ is the degree to which the individual appears to be able to interact with their environment. What are two examples?
____ reflects the depth and content of the arousal state. It is dependent on _____.
____ describes that set of neural processes that allow an individual to perceive, comprehend, and act on the internal and external environments.
Arousal; sleep and wakefulness
Awareness; arousal
Consciousness
_____ is the reproducible evidence of awareness exists such as responding to simple commands but with limited or absent communication.
Pt’s eyes open and close and the pt appears to track objects about the room and may chew and swallow food placed in the mouth. Pt does not respond to auditory stimuli and does not sense pain, hunger. There is ___ but not ____.
Minimally conscious state
Persistent vegetative state; arousal; awareness
_____ is individuals who have suffered brain injury that leaves them in a deeply unconscious state defined by apparent unresponsiveness to noxious, sensory stimuli; may have some reflexes and/or posturing.
____ is no EEG activity.
Coma
Irreversible brain death
J
Default mode network
_____ is required for arousal and awareness.
The cortex has no intrinsic mechanism for activation of ____ and ____.
Disruptions in consciousness result from smaller, subcortical lesions in the ____, _____, _____.
Cortical fx
Arousal and awareness
Brainstem, midbrain, hypothalamus
What are five arousal systems?
Excitatory AA:
Cholinergic:
Noradrenergic:
Serotonergic:
Dopaminergic:
The ____ is a network of neurons located in the brainstem and project to _____.
It descends to the SC along the ____ tract.
RAS; hypothalamus, thalamus, cortex
Reticulospinal tract
What is the fx of RAS?
Regulation of arousal and level of consciousness
Relays all ascending sensory info
H
H
The _____ contains subgroups of neurons and plays a role in promoting wakefulness through cortical activation.
It is important in generating ____.
Amygdala activation of PBN causes what?
What is it classified as?
Parabrachial nuclei complex
Respiration patterns during the waking state
Hyperventilation during anxiety states
Glutamatergic
J
J
How is PBN similar to RAS?
Both use EAA glutamate as their neurotransmitter
_____receive so much input that modality-specific info is lost.
Outputs are via the _____ used by RAS.
Neurotransmitter is ____.
Pedunculopontine tegmental (PPT) and laterodorsal nuclei (LDT)
Dorsal and ventral pathways
ACh
____ is the primary cause of wakefulness and REM sleep.
Cholinergic nuclei
J
J
Damage to the _____ doesn’t cause a coma but does produce severe cognitive deficits that are associated with a generalized slowing of cortical processes.
PPT/LDT
_____ is embedded within the RAS.
What are its two outputs?
Locus coeruleus
Ascending: dorsal and ventral pathways along with the RAS -> become the dorsal noradrenergic bundle
Descending: sensory modulation
What are the fx of the locus coeruleus?
What neurotransmitter?
Startle and alerting responses
Sleep-wake cycle
Behavioral vigilance
Norepinephrine
What is the alerting response?
What other response is also associated with this system?
An early indicator that the cortex is looking for or expecting sensory input.
Startle response
J
J
Serotonergic
What are the fx of the Raphe nuclei?
J
The ____ is embedded within the RAS.
What is the fx?
Ventral tegmental nuclei
What are three characteristics of the dorsal pathway?
Ventral pathway?
Arousal systems send axons to the thalamus
Synapse
Axons from the thalamus to cortex
Arousal systems send axons straight to the cortex
Synapse directly onto cortical neurons
Dorsal pathway
J
Persistent vegetative state causes the rostral regions of the _____ to show neuronal loss that exceeds that of the cortex.
They are ____ relative to their threshold.
Treatment of ____ can produce increases in cognitive fx/
Pons/midbrain/thalamus
Hyperpolarized
Levodopa
J
J
