Lecture 2

Question 1

4 issues in neurological assessment

Answer 1

• Reliability & Validity
• Premorbid functioning (tests usually tell us current functioning other than NART)
• Comorbid mental disorders, ie, depression commonly comorbid w brain injury, which reduces motivation, thus performance on tasks=invalid assessment resulting from depression not injury
• Compliance & malingering - client may not cooperate, motivated to perform well, or exaggerate or feign illness in order to escape duty or work (malingering)

Question 2

What are glial cells

Answer 2

• Supportive cells in CNS
  
  • surround neurons & hold them in place
  • supply nutrients & oxygen to neurons
  • insulate neurons from each other
  • play role in neurotransmission and synaptic connections by regulating clearance of neurotransmitters from the synaptic cleft
• Don’t conduct messages like neurons

Question 3

What is a neuron

Answer 3

Basic units of the nervous system.

most important part is the brain

Question 4

What are the parts of a neuron

Answer 4

• Cell body (soma)
• Dentrites
• Axon

Question 5

What is neurogenesis

Answer 5

growth of neurons

Question 6

What invertebrate was used to study the “axon”?

Why?

Answer 6

The giant squid.

The axon of the squid is 1000x larger than the mammalian axon, size of a pencil lead

• Showed the movement of ions in and out of the membrane allowing us to study the action potential

Question 7

4 structural types of neurons

Answer 7

Unipolar - only 1 neurite extending from the cell body

Bipolar - has 2 extensions (one axon and one dendrite). These are specialized sensory neurons for transmission of special senses (smell, sight, taste, etc)

Pseudounipolar - 1 process serving as an axon and a dendrite. Type of sensory neuron in PNS

Multipolar - single axon and many dendrites, allowing integration of info from other neurons

Question 8

3 types of neurons according to function

Answer 8

Afferent/sensory neurons

Efferent/motor neurons

Interneurons

Question 9

How does the neuron work?

Answer 9

• Neurons send messages electrochemically
• nerve cells are surrounded by a semi-permeable membrane, allowing some ions to pass through and blocks the passage of other ions
• Movement of ions is key to every electrical event that happens in neurons

Question 10

Anterograde amnesia

Answer 10

Inability to remember information learned after the injury (form new memories)

Question 11

What are ions

Answer 11

“electrically charged” chemicals

Question 12

What are the important ions in the nervous system?

Answer 12

Sodium and potassium (both have 1 positive charge, +)

Calcium (has 2 positive charges, ++)

Chloride (has 1 negative charge, -)

Question 13

Resting membrane potential

Answer 13

• neurons “at rest” when inside of neuron is negative relative to outside
• Resting membrane potential of a neuron is about -70mV (70mV less than outside)
• ion concentrations attempt to balance out on both sides of membrane but can’t because the cell membrane:
  
  • lets potassium ions (K+) cross easily, while chloride ions (CL-) and sodium ions (Na+) have difficult time. Protein molecules (A-) cannot cross. Therefore, there are more negative ions inside the neuron/more positive outside at rest
  • has pump using energy to move 3 sodium ions out for every 2 potassium ions it puts in

Question 14

Hyperpolarization

Answer 14

When the membrane potential becomes more negative at a particular spot on the neuron’s membrane

(hyper/depolarization occur when ion channels in the membrane open/close, altering the ability of different ions to enter or exit cell)

Question 15

Depolarization

Answer 15

when the membrane potential becomes less negative (more positive)

Question 16

What is an action potential?

Answer 16

• A large enough depolarization event can lead to production of an action potential
• (some event (a stimulus) causes the resting potential to move toward 0 mV
• When depolarization reaches -55 mV a neuron will fire an action potential. This is the threshold. If it’s not reached, no action potential will fire!
• An action potential in the neuron sends info down the axon
• For any given neuron, the size of the action potential is always the same (there are no big or small action potentials in one nerve cell) aka: All-or-none principle

Question 17

What is PET and what does it measure?

Answer 17

Positron Emission Tomography Measures brain function via the measurement of brain oxygen consumption, blood flow and glucose metabolism. Of these 3 measures, blood flow appears to be the most reliable

Question 18

Steps of an action potential

Answer 18

1. Resting potential: -70 mV, due to
2. Depolarization
3. Repolarization:
4. Hyperpolarization:

Question 19

“Synapse” = derived from “syn” and “haptein” meaning:

Answer 19

syn= together, haptein=to clasp

It is “THE GAP”

Question 20

most drugs affect the presynaptic ending w neurotransmitters, mitochondria and other cell organelles, synaptic cleft, or the postsynaptic ending?

Answer 20

Postsynaptic ending, containing receptor sites for neurotransmitters

Question 21

what is synaptic plasticity

Answer 21

Synaptic plasticity is the biological process by which specific patterns of synaptic activity result in changes in synaptic strength and is thought to contribute to learning and memory. Both pre-synaptic and post-synaptic mechanisms can contribute to the expression of synaptic plasticity.

Question 22

4 examples of synaptic plasticity

Answer 22

• Memory: loss of synapses in brain due to degenerative disease like Alzheimer’s or Parkinsons will cause a corresponding loss of function related to whatever those synapses did
• Neuropsychotherapy
• Gratefulness exercises
• Mindfulness

Question 23

What is Neuropsychotherapy?

Answer 23

changing the brain, not directly, but through focusing on life experiences encountered by the person. Life experiences are meaningful with regard to the needs that are embedded within the brain structures of each human.

Neuropsychotherapy strives to shift the brain into a state that enables these basic needs to be fully satisfied

Question 24

Excitatory neurotransmitters

Answer 24

• Increase the rate or likelihood of a neuron firing by depolarizing the neuron
• neurotransmitters bind to ion channels allowing Na+, sometimes Ca2+ (calcium) into the cell, exciting the neuron

Question 25

Main excitatory neurotransmitters:

Answer 25

Glutamate

Acetylcholine

Question 26

Inhibitory Neurotransmitters

Answer 26

• Decrease the likelihood or rate of a neuron firing by hyperpolarizing the neuron
• Inhibitory molecule binds to an ion channel that is permissive to negatively-charged ions Cl- (chloride) to flood into the cell, inhibitiing firing

Question 27

2 main inhibitory neurotransmitters

Answer 27

• GABA (gamma-aminobutyric acid)
• Glycine

Question 28

What is the most abundant neurotransmitter in the body

Answer 28

Acetylcholine.

• first neurotransmitter to be identified. The cehmical that motor neurons release in order to activate muscles
• Neurons that release it are called cholinergic
• because of its muscle-activating function, and also b/c of its functions in the autonomic nervous sytem and brain, many drugs exert their effects by altering cholinergic transmission
• many venoms/toxins produced by plants, animals, bacteria, and chemical nerve agents cause harm by inactivating or hyperactivating muscles via this neurotransmitter

Question 29

What is a Monoamine?

Answer 29

A class of neurotransmitter derived from a single amino acid

Question 30

main monamines (`5)

Answer 30

• dopamine (DA),
• norepinephrine (noradrenaline; NE, NA),
• epinephrine (adrenaline),
• histamine,
• serotonin (SER, 5-HT)

Question 31

2 amino acid-class neurotransmitters

Answer 31

Glutamate

GABA

Question 32

Serotonin

Answer 32

(Monoamine)

Relatively rare in nervous system

regulating sleep, eating, emotional behaviour

antidepressants used by reuptake

Question 33

Dopamine

Answer 33

(Monoamine)

Involved in movement and reward, thought to play role in addiction

Question 34

what does norepinephrine do?

Answer 34

• Increases blood pressure, triggers release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system
• More to do with blood vessels

Question 35

What is Epinephrine?

What does it do?

Answer 35

• Hormone to increase cardiac output and raise glucose levels in blood
• Numerous in nervous system
• more to do with the heart

Question 36

What does Glutamate do?

Answer 36

• Involved in learning and memory
• generally has excitatory actions
  
  • when it interacts w receptors on a neuron, neuron is more likely to fire and action potential
• one type of plasticity: long term potentiation (strengthening of synapses based on recent patterns of activity)
  
  • occurs at glutamate snapses in the hippocampus, neocortex, and other parts of brain
  • must be “reuptook” in the synapse otherwaise high levels can destroy neurons - excitotoxicity

Question 37

What is GABA?

Answer 37

• Gamma-aminobutyric Acid (an amino acid neurotransmitter)
• The primary mediator of inhibitory neurotransmission
• has role in modulating dopamine
• role in amygdala and hippocampus for memory and anxiety
• early anxiety treatment targets GABA receptors through sedating meds eg. benzos.
• although effective, these meds have adverse effects (dependence, sedation, ataxia, memory impairments, weakness