Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neur 1202 > Lec 12/13 > Flashcards

Lec 12/13 Flashcards

1
Q

What does the term reward refer to?

A

refers to stimuli that are in some way desirable or positive and can affect behavior.
Examples: food, money, drugs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why do humans find certain activities naturally rewarding?

A

Humans, like other animals, naturally find certain activities to be rewarding. This is with good reason, as rewarding activities are usually critical to survival.
Examples: eating, sleeping, sex, exercise, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why is the reward stimuli different for everybody?

A

Rewarding stimuli can be different depending on an individual’s personal experience. Therefore, we learn to value more than just what we’re born liking.
The ability to learn new rewards is also valuable, because it teaches us to repeat successful behaviors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How was the reward system discovered?

A
  • -Olds and Milner (1954) discovered the phenomenon of intracranial self-stimulation (ICSS) more or less by accident
  • -James Olds accidently implanted an electrode the wrong way. He was supposed to implant it right above the reticular formation, but he didn’t wait for the substance to harden around the implanted electrode and he took out the rat’s head from the halo structure that holds it in place. This caused the electrode to slightly move. He noticed that the rat liked the stimulation and would repeatedly press the lever that caused the stimulation. He then realized that something is up and he opened the brain up and realized it was because it was in another area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What did the discovery of the ICSS show about addiction?

A

–Rats would press the lever thousands of times an hour, ignoring everything else that the experimenters could offer. Rats would ignore food, water, access to a sexually receptive female, and whatever other rat treats the experimenters could think of
–To researchers, this sort of behavior closely resembled the behavior of human drug addiction
They reasoned that the brain areas targeted by the electrodes must therefore be involved in drug addiction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the official name for the reward circuit and what does it mean?

A
  • -mesocorticolimbic dopamine system
  • -meso=middle (midbrain where VTA is)
  • -cortico=cortex (where axons from VTA is projected)
  • -limbic=limbic system (where axons from VTA is projected)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What main neurotransmitter is used in the reward circuit?

A

–dopamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does the reward system work?

A
  • -It starts with the Ventral tegmental area (VTA) in the midbrain which contain neurons that produce dopamine
  • -axons from these neurons project to the hippocampus, nucleus accumbens (NAc), and prefrontal cortex (PFC)
  • -the VTA is tonically inhibited (GABA is coming from different regions to inhibit the VTA)
  • -however, when a rewarding stimulus is detected, the VTA is disinhibited and it fires (releases dopamine) in the hippocampus, NAc, and PFC
  • -Hippocampus: allows us to remember where in the environment we had the stimuli
  • -NAc: the expectation and experience of rewarding stimuli. Unexpected rewards lead to especially large dopamine release
  • -PFC: allows us to plan for it again in the future
  • -together with the PFC and Hippocampus, it allows for the experience of reward, as well as the need to go after it again
  • -in the case of natural, healthy, rewarding stimuli, this system is quite useful
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the reward system on drugs?

A

–addictive drugs lead to supraphysiological dopamine. In other words, a dopamine release that is much larger than what would normally be seen with naturally occurring rewards.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is addiction?

A
  • -Addiction is a state of uncontrolled drug use that persists in spite of negative consequences associated with taking or procuring that drug
  • -Negative consequences include: health effects, cost, family disruption, loss of (legal) employment, etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does addiction develop?

A
  • -Addiction develops over multiple exposures to addictive drugs. Users progress from least harmful (recreational) use to most harmful (daily/binge use)
  • -Addiction is not an inevitable consequence of trying a drug, but repeated drug use does raise the risk of addiction.
  • -only 4% of people who try drugs become addicted
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do we diagnose addiction?

A

–The definition of addiction remains controversial.
Addiction is not a diagnostic term
–DSM-5 now uses term “Substance Use Disorder”, and also includes behavioural addictions, diagnosed under “Addictive Disorders”.
–According to the DSM, patients must show 2 or more of 11 listed behavioural criteria (within the past year
–Like other disorders, individuals are scored on a spectrum, from mild, moderate to severe substance use disorder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is drug tolerance?

A
  • -Increased amount of a drug needed to achieve intoxication, or a diminished drug effect with continued drug use of the same amount of a drug
  • -Can become tolerant to some aspects of a drug, but not to others
    e. g., Alcohol: Tolerance to intoxicating effects achieved faster than tolerance to motor (cataleptic) effects and this is why you want to drink more even though you can walk or stand properly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Can have ___________ blood levels of drug and ____ appear intoxicated

A

–very high; not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is drug withdrawal?

A

Behavioural and physiological symptoms that occur upon cessation of drug use

  • —>Opposite to drug effects; compensation for drug effects on body
  • —>Severity may change with characteristics of the user, history of drug use
  • E.g., a hangover
  • Muscle aches and cramps, anxiety attacks, sweating, nausea, convulsions, death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why shouldn’t you take tylenol after drinking?

A

You shouldn’t take Tylenol (acetaminophen) because it is metabolized using the same group of enzymes that alcohol is. If you take acetaminophen in high doses regularly while drinking, the metabolic pathway will go to the alcohol and not the Tylenol so you could have dangerous levels of acetaminophen in your bloodstream
Advil is better

17
Q

What is the technical definition of an addiction?

A

“A syndrome at the centre of which is loss of control over a reward-seeking behaviour”

Robert West, Theory of Addiction

18
Q

What happens if a pregnant woman is a heroine addict?

A

If the mom is a heroin addict, the baby is not one either. It may show tolerance and withdrawal, but that doesn’t define addiction. There’s no loss of control over reward-seeking behavior (babies don’t really have much control over anything). The DSM 5 states in the beginning that ”the individual has shown problematic pattern of use leading to significant psychological distress over the last 12 months” so the baby does not demonstrate that.

19
Q

Each drug has ___________

A

different brain targets

20
Q

What is cannabis?

A
  • -Most commonly used illegal drug in the world
  • -Most controversial
  • -Comes from the cannabis sativa and cannabis indica plant
  • -Over 80 cannabinoids known
  • —>Most common is Δ-9- tetrahydrocannabinol (Δ9-THC)
  • —>Also contains cannabidiol (CBD)
21
Q

Why don’t we use the term marijuana?

A

We don’t use the term marijuana anymore because it refers to a very specific product of the cannabis plant. We use cannabis instead because we can talk about all the cannabinoids, edibles, etc

22
Q

What does psychoactive mean?

A

Psychoactive means it affects your brain cells –neurons and glia

23
Q

What is the difference between THC and CBD?

A
  • -CBD IS psychoactive (it binds to receptors on brain cells), but it is not intoxicating (won’t give you high)
  • -THC is the main psychoactive ingredient; responsible for the “high” associated with use however pure CBD won’t
24
Q

What is the inhalation administration of cannabis?

A

– 50% enters lungs, almost all of that enters body
Reaches brain in about 30 sec, peaks ~ 30–60 min., lasts 3–4 hours; subjective state for 12 hours
–Vaping – peak concentrations occur 10 min after administration
Distributed everywhere; likes to stay in fatty tissue

25
Q

What is the oral administration of cannabis?

A
  • -Absorbed from gut slowly; absorption improved by adding oil (e.g., baking)
  • -Onset is 1h, peak 2-3 h
  • -Larger oral dose needed to have same effect as inhaled
26
Q

What are the cognitive effects of cannabis?

A

Decreased attention, concentration (easily distracted), learning
Short-term memory impaired
—->Temporal disintegration = loss of ability to retain and coordinate information for a purpose (related to distorted time sense)

27
Q

What are the behavioural effects of cannabis?

A

Decreased movement, increased talkativeness

28
Q

What are the perceptual effects of cannabis?

A
  • -Decreased visual perception, especially peripheral
  • -Decreased pain perception (analgesic)
  • -Decreased time perception (overestimate passage of time; i.e., 30 mins has passed and you feel like it’s been 3h)
29
Q

What are the subjective effects of cannabis?

A
  • -May have to learn to discriminate subjective effects

- -can be separated into four stages: the “buzz,” the “high,” the stage of being “stoned,” and the “come-down.”

30
Q

How is your mood affected by cannabis?

A

Sometimes mood swings to anxiety and/or panic, especially at higher doses
–Can sometimes produce transient psychotic symptoms such as depersonalization, derealization, agitation, and paranoia
More than any other known drug, effects are modulated by surroundings (if others around are high and happy, then so will you but if others are sick and tired then you’ll be affected similarly)

31
Q

What does pharmacodynamics mean?

A

–how the drug interacts with the body (how is cannabis working in the brain to produce these effects)

32
Q

What are the pharmacodynamics of cannabis?

A

endocannabinoid (eCB) system

  • -Endogenous ligands: anandamide (AEA) and 2-arachidonoylglycerol (2-AG) produced by cells and released on demand
  • -Two main receptors: CB1 (brain) and CB2 (immune system)
  • -Anandamide (AEA) and THC bind to CB1
  • -2-AG and CBD bind to both CB1 and CB2
33
Q

Where are the concentrations of CB1 receptors?

A 
Basal Ganglia
--movement
Cerebellum
--movement
Cerebral Cortex
--higher cognitive functions
Hypothalamus
--appetite
Hippocampus
--learning, memory, stress
Spinal cord
--peripheral sensation and pain
Medulla
--nausea/vomiting, chemoreceptor trigger zone (CTZ)
34
Q

How does THC work in the brain?

A

–CB1 receptors are located presynaptically on axon terminals
–AEA and 2-AG are retrograde messengers—carry information in the opposite direction from normal (i.e., postsynaptic to presynaptic)
–When the neurotransmitters are pumped out and binds to the receptors post-synaptically, It will promote the synthesis of endocannabinoids in the post-synaptic cell
It then produces another signal that causes an upregulation of anandamide
Anandamide goes back and binds to CB1 receptors located presynaptically and when it binds to these receptors, it serves to shut down the trafficking of the vesicles to the presynaptic membrane controlling the release (negative feedback loop)
–THC mimics the shape of anandamide and it will serve to bind to these CB1 receptors (that presynaptic cell may not even have to be activated when we get THC binding to the CB1 receptors and shutting down presynaptic cell firing)
the combined effects of THC is particularly when we’re acting on GABAergic inputs to the VTA, GABA which is normally inhibitory and inhibits dopamine, THC comes and binds to the CB1 receptors and prevents the release of GABA which causes dopamine to be released in the VTA

35
Q

What are the harms of chronic cannabis use?

A
  • -Development of paranoid disorders (anxiety, schizophrenia)
  • -Carcinogenic
  • -Depression/suicidality
36
Q

What are the red flags for use?

A
  • -Family history of psychiatric illness (particularly depression/anxiety)
  • -Current psychiatric illness
  • -Lifetime history of trauma
  • -Using alone, or to relieve anxiety/stress/depression/poor mood

Neur 1202 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions