Cog Neuro Lec 2 - Fundamentals of neurotransmission, neuroanatomy

astrocytes

• BBB

• respond to brain injury

• neuro development (building the bridges for the neurons)

oligodendrocytes

• collect waste (dead and dying cells)

• important after brain injury

• only brain and spinal cord

schwann cells

found in arms, legs (periphery)

• insulate neuro signals

• development

• maintenance

• function

• regeneration of peripheral nerves.

• same as oligodendrocytes but for the peripheral nervous system

what are the three classes of neurons?

• motor neurons

• sensory neurons

• interneurons

  • overwhelming number of our neurons

  • complex types of information

  • integration across brain regions and within them

  • not just motor or sensory, more complex

what is the all-or-none principle

whether a neuron sends or does not send a signal based on threshold

does it matter how stimulated a neuron is for the action potential spikes to vary

no, the neuron will send the same action potential, however if there is more stimulation, it will send more signals

what does the axon hillock do?

it decides if there is enough action potential 

which glial cell speeds the signal of a neuron up through insulation/ where do myelin sheaths come from?

oligodendrocytes

what is saltatory conduction?

the jumping of the signal from each node of ranvier

which disease has different symptoms depending on the place of origin

Multiple Sclerosis (MS)

what causes the MS?

the immune system attacking the myelin in the brain

where is MS more common and what is it correlation?

north western areas (canada, england) correlated with vitamin D among other things

what is Amyotrophic Lateral Sclerosis (ALS)

• specific to motor neurons

• fast development of paralysis

• can cause you to stop breathing

what is excitotoxicity? and how did they find that this was what ALS was?

increased neural activity

• found due to the fact if you give someone with ALS reducing neural activity drugs, it slows the progression

Ischemia

when parts of the body do not get enough oxygen to perform tasks

what causes neural failure

when the neuron does not get enough oxygen to perform its task (neural ischemia)

what kind of stroke is most common?

ischemic stroke

• blood clot to an area of the brain

• associated with diet and overall health

if treatment for a ischemic stroke is performed in how x number of minutes, what can happen to the neurons?

if within 90 minutes, there is treatment, then the neuron can come back to life

what are the signs of a stroke

• facial drooping on one side

• muscle weakness of legs or arms on one side

• slurred speech

how much oxygen does the brain use up?

25% of our oxygen

what causes presynaptic neurons to release neurotransmitters into postsynaptic neurons

the influx of Ca2+ into the cell binds to the vesicles to release at the synapse

where is dopamine produced

1. in the brainstem in the substantia nigra 

2. ventral tegmental area (decision making)

what is dopamine good for?

• Higher-order cognition

  • moment-moment consciousness

  • used to not loose train of thought

• Voluntary movement

  • in other areas such as the basil ganglia

• Reward/reinforcement learning

  • operant conditioning

  • addiction

what happens to the substantia nigra when you have parkinson’s disease

90% of substantia nigra has died 

what are some diseases associated with dopamine

• Parkinson’s disease (decrease)

• psychotic thoughts/behaviours

• addiction

where is norepinephrine produced

locus coeruleus

what causes cognitive arousal/ attention

norepinepherine

what is norepinephrine used for?

• cognitive arousal/attention

• memory and mental flexibility

  • being open to changing how you think about something

• mood

Dysfunctional levels associated with norepinephrine

• Alzheimer’s disease

  • reduction in consciousness, loss of memory, mood changes

• Mood disorders

• Visuospatial neglect

where is serotonin produced?

raphe nucleus

what is serotonin used for?

mood

Dysfunctional levels associated with serotonin

• mood disorders

• psychotic thoughts/behaviours

where is acetylcholine (Ach) produced

basal forebrain

what is acetylcholine used for?

• Sensory processing/attention

• Learning and short-term memory

• Movement (peripheral nervous system - PNS)

Dysfunctional levels associated with

• Alzheimer’s disease

• Myasthenia gravis (PNS)

  • lack of muscle movement

what is the yerkes-dodson curve?

An individual’s baseline level of a neurotransmitter

what’s of challenge of psychopharmacology?

effecting one hormone may effect the yerkes-dodson curve of another hormone/neurotransmitter

what is the corticospinal tract/pyramidal tract for and where does it extent from

it is there for voluntary movement

path: motor cortex → midbrain → medulla → switch sides (medullary pyramids) → spinal cord

what does the medial lemniscal tract carry

carries touch information and proprioception information

what is proprioception?

knowing where your body is in space without vision

what does the lateral spinothalamic tract carry?

pain and temperature information

what two tracts terminate in the parietal lobe?

the medial lemniscal tract and the lateral spinothalamic tract

whats the difference between ventral and dorsal information?

dorsal is sensory (dorSal → SenSory)

ventral is motor

what is a dermatome map?

map of the human body where parts of the spinal cord control

what does the frontal lobe do?

• higher order cognition

• advanced thinking

• movement/motor control

• speeking/language production

where does broca’s aphasia take place

frontal lobe

parietal lobe fucntion

• crucial for attention

• somata sensation (spacial awareness on your body

occipital lobe function

visual processing

temporal lobe function

• hugely involved in memory

  • dementia is here

• hearing

• language comprehension

  • wernike’s area is here

where is the motor cortex?

frontal lobe

where is the somatosensory cortex?

parietal lobe

what is the brain mostly composed of in terms of cortex?

association cortex

what do primary, secondary, and association cortex’s do?

primary and secondary only focus on one or two input/output functions but most of the brain processes multiple functions at a time

what is the lymbic system involved in?

emotion and memory

amygdala

• processing of emotion

• almond-shaped structure

• end of hippocampus

what is the role of the hippocampus?

creation new conscious or declarative memories

thalamus

large nucleus that helps transmit sensory information

• important in consciousness

• every sense except for olfaction synapses in the thalamus

corpus collosum

white matter tract that connects the left and right hemispheres

what sense does not get relayed/synapsed in the thalamus?

olfaction

basil ganglia

• procedural learning (ex. shooting basketball, bike)

• routine/autopilot (ex. driving)

what are the three parts of the basil ganglia?

1. caudate nucleus

2. putamen

3. globus pallidus

cerebellum

• thought it was only for motor coordination (smooth, continuous, accurate movement)

• language and memory

• executive function

how can we detect meningitis or other neural ailments in the brain?

taking the fluid from the spine

what are the roles of the ventricular system

• to keep the brain stationary so that it doesn’t move around and bruise the brain (buoyancy) 

• eliminates waste from nervous system

what arteries bring blood to the brain and to where?

through the vertebral artery (back) and the common carotid artery (front) to the circle of willis

what are the three major arteries of the brain

anterior cerebral artery, middle cerebral artery, posterior cerebral artery

what is the middle cerebral artery distribution?

frontal, parietal, and temporal lobes (lateral surface of the cortex)

anterior cerebral artery distribution

the medial portions of the frontal and parietal lobes

posterior cerebral artery distribution

ventral part of the temporal lobe and all of the occipital lobe

neuropsychological conditions caused by stroke are caused by damage to what?

the middle cerebral artery distribution