Reward Flashcards
What can aggression lead to if not inhibited?
Violence
Involved with cognition, memory, attention, emotional behavior, and learning
Mesocortical dopamine pathway
Positive effect an object or condition has on the user
Reward
What do antisocial, violent people show?
Abnormalities of hypothalamic function
Involves being against different species for food, few vocalizations, attack head or neck
Predatory aggression
4 parts of the mesolimbocortical dopamine system
- Ventral Tegmental Area (VTA)
- Medial forebrain bundle (MFB)
- Nucleus accumbens (NA)
- Prefrontal cortex (PFC)
Gene x environment interactions determining aggression
High and low activity versions of MAOA and child maltreatment and antisocial behavior
The target for the mesolimbic pathway in the mesolimbocortical dopamine system
Nucleus accumbens (NA)
Can brain damage cause aggression?
Possibly
Involved in pleasure and reward seeking behaviors, addiction, emotion, and perception
Mesolimbic dopamine pathway
Increases reactivity to threatening stimuli
Testosterone
How do impulsive brains lead to a higher risk of drug use/addiction?
Fewer or less functional D2 receptors leads to poorly regulated dopamine release which leads to high amounts of dopamine in response to natural rewards or drugs
Large white matter tract containing fibers from ventral tegmental area to nucleus accumbens, olfactory regions, peri-amymdalaloid regions, and septal area
medial forebrain bundle
The dopamine release center of the mesolimbocortical dopamine release system
Ventral tegmental area (VTA)
The major reward pathway
Mesolimbocortical Dopamine System
The fiber pathway that connects structures in the mesolimbocortical dopamine system
Medial forebrain bundle (MFB)
What does stimulation of the amygdala cause? Damage?
Stimulation = aggression Damage = tameness/calmness
Rhesus Monkeys and 5HT
Low in social hierarchy = low in 5HT. Attempt to increase status by initiating aggression
The subjective feeling of pleasure or satisfaction that occurs when one receives a reward
Liking
What do genotypes associated with violence increase?
Risk of alcoholism
What does lateral hypothalamus stimulation cause?
Predatory aggression
What does stimulation of the hypothalamus cause?
Rage
3 examples of places reward can come from
- Reinforce pleasurable activities
- Behaviors beneficial for survival
- Behaviors associated with drug highs
When are dopamine bursts in the ventral tegmental area highest?
Right after an unexpected reward or in anticipation of a reward
Carry a variety of functions, like inhibition of Ca channels and control of pacemaker activity
Postsynaptic D2 receptors
Connects the midbrain and limbic system
Mesolimbic pathway
Characterized by mouthing, hyper-sexuality, visual agnosia, loss of normal fear and anger, memory loss, distractibility, seizures, and dementia
Kluver-Bucy syndrome
How does delay in reward relate to dopamine release in the ventral tegmental area?
No or short delay = highest firing and dopamine release
Long delay = lower firing and dopamine release
What do the brains of impulsive people show?
Fewer or less functional D2 receptors
Affects processing of aversive stimuli by limbic system
5HT
Facilitates inhibitory activity of prefrontal cortex
5HT
Involved in movement and sensory stimuli
Nigrostriatial dopamine pathway
What does stimulation of the septal area cause?
Intense, pleasant sexual feelings
How does the ventral tegmental area connect to the nucleus accumbens in the mesolimbic pathway?
Medial forebrain bundle
What is the gene related to aggression?
MAOA
Bilateral loss of the amygdala
Kluver-Bucy syndrome
What does the cortex do to the hypothalamus?
Inhibits it
What does stimulation of the medial thalamus cause?
Unpleasant tactile irritation. Feels like bugs crawling on you
Attacks to kill aggression
Predatory aggression
Heritability and gens of aggression
Impulsive aggression heritability between 44-72 percent. Aggression can be selectively bred in animals
Sometimes ___ is better than ___
Looking forward to reward, the actual reward
Just for show aggression
Affective aggression
What can some seizures, like temporal lobe seizures, cause?
Agression
High levels of sympathetic nervous system activity in this aggression
Affective aggression
What does electrical self-stimulation of the medial forebrain bundle lead to?
Reward. In rats, the will do this over everything else bc it gives a reward
What does the MAOA gene do?
Produces monoamine oxidases
The effects that rewards have in promoting learning
Reinforcement
Wanting or craving leads to this whereas liking does not
Addiction
Increases in competitive situations
Testosterone
What is important to note about most people with the low MAOA gene?
They are normal, law-abiding people
The target for the mesocortical pathway in the mesolimbocortical dopamine system
Prefrontal cortex (PFC)
3 dopamine pathways in the brain
- mesocortical
- nigrostriatial
- mesolimbic
What NT is involved with wanting and addiction?
Dopamine
Ventral tegmental area to prefrontal cortex
Mesocortical dopamine pathway
Inhibits violence by influencing empathy
5HT
What is prenatal exposure to testosterone correlated with?
Higher aggressiveness
What happens to self-stimulation of the MFB if dopamine antagonists are infused into the nucleus accumbens?
Rewarding effect is blocked
How is aggression related within species?
It is related to dominance
Ventral tegmental area to nucleus accumbens
Mesolimbic dopamine pathway
Greatly valuing the reward now over a greater reward in the future
Temporal discounting
Important for regulating dopamine release
Presynaptic D2 receptors
Involves intimidation, not killing for food, vocalizations, threatening posture
Affective aggression
How do presynaptic D2 receptors work?
Sense high concentrations of dopamine floating around in the synapse and inhibit the cell which released the dopamine and reduce the amount of NT it will release next time
Low levels of this predict aggressiveness
5HT
Important role in cost-benefit analysis. Mesocortical pathway
Anterior cingulate cortex (ACC)
What does medial hypothalamus stimulation cause?
Affective aggression
No activity in sympathetic nervous system in this aggression. Calm heart rate
Predatory aggression
Manages delayed gratification. Mesocortical pathway
Orbitofrontal cortex
Reduces the inhibition of aggression normally managed by the cingulate and frontal cortices
Alcohol
What does removal of the cerebral cortex produce?
Sham rage
Rage without any cause
Sham rage
The desire to obtain a reward. Great when you get it, but don’t have it yet
Wanting