Lecture I Flashcards
4 main aspects of neurons
Output, transfer, modulator, input
Neurons are different from normal cells (4):
Axons and dendrites are specialized structures to transmit information through APs.
They tend not to reproduce after birth.
Connections can alter.
Each cell type has its own specialized function.
Hemorrhagic stroke
Tear in vessel leaks blood into brain tissue.
Ischemic stroke
Blood clot in vessel blocks blood supply to certain brain tissue.
Measuring brain activity via (4):
APs or local field potentials (electrophysiology)
Electromagnetic fields at scalp (EEG/MEG)
Manipulating neural activity (TMS/tDCS)
Blood oxygenation (fMRI/PET/fNIRS)
Most important NTs (6):
Glutamate, GABA, dopamine, serotonin, acetylcholine, norepinephrine.
Whether a NT inhibits or excites depends on…
Target cell receptor types.
Acetylcholine (ACh) (5):
Both excitatory and inhibitory functions.
Maintain body states, muscle contraction, digestion, etc.
Skeletel muscle: nicotinic receptors.
Heart muscle: muscarinic receptors.
Brain, spinal cord (CNS): interneurons.
In AD, … levels are …
ACh levels are low.
Dopamine (3):
Both excitatory and inhibitory functions.
Reward system, mood, posture and movement, wakefulness.
Areas producing dopamine mostly in midbrain.
In PD, … levels are … - causing …
Dopamine levels are low - causing bradykinesia.
In schizophrenia, … levels are … - causing …
Dopamine levels are low - causing hallucinations.
Norepinephrine (5):
Both excitatory and inhibitory functions.
Released from adrenal medulla by fear and stress.
Increase heart rate, decrease digestion.
Main NT of sympathetic nervous system.
Related to epinephrine (fight or flight).
Serotonin (5-HT) (4):
Mainly inhibitory functions.
Brain’s key monoamine, modulatory NT.
Gut to brain, brain to gut.
Influences effects of other chemical messengers.
In depression, … levels are …
5-HT levels are low.
GABA (4):
Mainly inhibitory functions.
Main inhibitory NT, prevents excessive signaling.
Released from both axon terminals and dendrites.
Synthesized from glutamate.
Glutamate (5):
Mainly excitatory functions.
Most abundant free amino acid.
NMDA and AMPA are major receptors.
On postsynaptic neuron, glutamate binds to them.
Promotes learning by synaptic plasticity.
Oxytocin (4):
Both inhibitory and excitatory functions.
Loyalty and trust, mother-child bond, love, milk from mammary glands.
Modulates uterus contractions during birth.
Made and released from hypothalamus via pituitary gland.
When is EEG measurement good? (4)
Mass activity, synchronized activity, close to scalp, no noise sources.
EEG measures primarily …, not …, mostly in the …
Local field potentials, not APs, mostly in the cerebral cortex.
Advantages of EEG (2):
Relatively low costs.
High temporal resolution.
Disadvantages of EEG (2):
Only surface structures.
Low spatial resolution.
… electrodes are enough to measure P100, N200, P600, etc.
… electrodes are enough for localization.
32-64
128
2 types of EEG waves:
Aroused = low amplitude, high frequency = fast waves Relaxed = high amplitude, low frequency = slow waves
Aroused waves
Low amplitude, high frequency = fast
Relaxed waves
High amplitude, low frequency = slow
During arousal: During relaxation: During sleep: During deep sleep: Even less active:
Arousal: gamma (32+ Hz) and beta (16+ Hz) Relaxation: alpha (8+ Hz) Sleep: theta (4+ Hz) Deep sleep: delta (4- Hz) Less active: coma
Gamma waves
> 32 Hz, superlearning
Beta waves
16-31 Hz, analytical thinking and processing information
Alpha waves
8-15 Hz, eyes closed or very relaxed
Theta waves
4-7 Hz, sleep, REM, deep meditation, dreaming
Delta waves
< 4 Hz, deep dreamless sleep
Theta/beta ratio
Lower ratio = more arousal
Higher ratio = less arousal
High ratio = high theta = low Hz = low arousal
ADHD
Increased theta/beta ratio = less arousal (less control?)
Hyperactive due to less cortical arousal
Treatment: stimulantia
Low spatial frequency - cycles
0.6 cycles per degree
High spatial frequency - cycles
4.8 cycles per degree
ERP - temporal resolution
High
