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26 Cards in this Set
- Front
- Back
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In the cerebral cortex, what are the cortical columns?
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Basic independent computational units
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How are columns interconnected?
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They are interconnected to other columns throughout the entire brain!
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What are the two things that thalmic neurons stimulate?
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Cortical columns and reticular neurons
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What do cortical columns stimulate?
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reticular neurons
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What do reticular (thalmic) neurons do?
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Reciprocally inhibit each other and inhibit thalmic neurons
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What two "modes" are created by the feedback relationship?
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-Transmission mode (thalmus driven by specific sensory input)
-Burst mode ("reverberation" causes burst of activity in thalmic neurons and cortical columns) (sensory stimuli is minimal) |
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What switches these modes?
What happens if this system is disrupted? |
-The brain stem
-Loss of consciousness |
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What are the 3 methods of recording cortical activity?
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-EEG (general, look for seizures, noninvasive)
-fMRI (general, metabolic activity, noninvasive) -PET (general, invasive!!) |
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What does the EEG represent the activity of?
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Pyramidal cells and Post Synaptic Potentials!!
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If you see a down wave on an EEG, what is it going towards?
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The positive
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EEG Paterns: Low amplitude, High Frequency?
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-Desynchronized cortical activity
-Alertness -Transmission mode |
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EEG Patterns: High Amplitude, Low Frequency
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-Sychronized cortical activity
-Drowse or Asleep -Burst mode |
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What frequency EEG band would you have is you were Alert, Awake?
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Beta (13-30 Hz)
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What frequency EEG band would you have is you were Relaxed?
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Alpha (8-13 Hz)
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What frequency EEG band would you have is you were Sleeping?
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Theta (4-8 Hz)
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What frequency EEG band would you have is you were Exhibiting a pathology?
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Delta (0.5 - 4 Hz)
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What are three things you can use and EEG for?
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Diagnose sleeping disorders, epilepsy, cerebral death
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What must be present for the patient to be fully aware?
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-Alert, awake, and oriented
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What is the situation with the brain in a vegitative state?
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-The cortex is widely damaged
-But the brainstem is mostly functional |
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What is the state of the brain in a brain dead person?
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-Brainstem and cortex are mostly nonfunctional
-Cardiovascular and respiratory system may still be functional |
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Confusion-
Signs: Cause: Duration: |
-SLowed thinking, difficulty following commands, disoriented to TIME and PLACE, slow SPEECH
-Concussion, contusion, increased ICP -Temporary, A few minutes |
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Stupor-
Signs: Cause: Duration: |
-Minimal level of consciousness, need strong stim to arouse
-Early relapse after being aroused |
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Coma-
Signs: Cause: Duration: |
-CANT be aroused with strong stim, metabolic act. of brain reduced from normal, NO memory of time
-Drug induced, decreased plasma Na, hypoglycemic, altered plasma pH -Limit water intake (if Na issue), is fixable |
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Persistant vegitative state-
Signs: Cause: Duration: |
-May chew, swallow, smile, cry, fixate eyes, NO cognitive ability, no relationship to events surrounding patient
-incomplete loss of cortical funct., but insufficient masss of cortex available to sustain conscious state -Irreversable |
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How is cerebral death like/unlike PVS?
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-Like: unrousable by any means
-Unlike: apnea does not respond to pH drive |
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What (diagnostically ) do you see with cerebral death?
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-Flat EEG (watch out, REVERSABLE drug coma also produces a flat EEG)
-BAER usually reveals evidence of brinstem nonfunction |
