Reward and Addictive Behaviours Flashcards
Limbic System:
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Reward Flowchart:
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Drug Use vs Drug Misuse:
any psychoactive recreational substance use/experimental use
any unsanctioned recreational substance use
Problematic/Hazardous Drug Use:
use of a psychoactive substance at amounts or rates likely to lead to problems
Harmful use of substances must be dependent.
True or False?
False
Dependent Use:
persistent uncontrolled drug use repeatedly leading to multiple harmful consequences
Addicition
a state in which a person engages in a compulsive behaviour, even when aware of potentially negative consequences - behaviour is reinforcing (rewarding or pleasurable)
loss of control in limiting intake
Tolerance:
a state in which a person no longer responds to a drug or substance
a higher dose is required to achieve the same effect
also referred to as the hyposensitisation syndrome
Dependence:
a state in which a person functions normally only in the presence of a drug
manifested as a physical homeostatic disturbance when the drug is removed
Categories of Harm Associated with Substance Abuse Disorders:
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Life Cycle of Addiction:
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What are the series of structures contributing to incentive salience?
The mesocorticolimbic circuit
also implicated in associative learning eg; taking cocaine in a nightclub, nightclubs are associated with craving for cocaine
What structures are used in the mesocorticolimbic circuit?
- mesolimbic system
- mesocortical system
addiction also involves:
- PFC
- amygdala
- hippocampus
When will the mesocorticolimbic system be activated?
in response to many stimuli
dopaminergic response
central to motivation
Pathway for Reward and Reinforcement:
addictive drugs activate this system
Addictive drugs cause more powerful and reliable activation of ——– than natural rewards/
- behaviour activating system
Mesocorticolimbic Circuitry:
- initiates in the ventral tegmental
area - travels along the mesolimbic
pathway to the nucleus
accumbens (linked to emotional
processing) - mesocortical pathway originates
from the ventral tegmental area
and loops up into the prefrontal
cortex and cingulate gyrus - cingulate gyrus is also linked to
emotional processing - nucleus accumbens is the key
structure in secreting the extra-
cellular dopamine
Nucleus Accumbens
- inner core = linked to basal ganglia
and implicated in movement - shell = part of amygdoloid
complex and links into the limbic
system and hence the reward-
addiction pathway and responsible
for the secretion of dopamine
Dopaminergic processing in a normal reaction resulting in a
motivational state
Reward-addiction: More than just Dopamine:
Opiates, cannabinoids and alcohol can act directly act on the nucleus accumbens via non-dopaminergic mechanisms
Functions of the Reinforcement System:
- detect reinforcing stimulus to
recognise something positive has
occurred and learning from
experiences - strengthens neural connections
via synaptic plasticity leading to
long-term potentiation
Dependence:
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Why do craving persist for years?
due to the previous homeostatic changes
the synaptic remodelling
Cocaine and Amphetamines Effects:
- psychosis; evidence of
dopaminergic involvement in the
positive symptoms of psychosis - cellular and molecular changes
that promote dysregulation
can result in hypofrontality, in which there is decreased cerebral blood flow to the pre-frontal cortex
