neurobiologia adictiei

Question 1

What do neurones do?

Answer 1

Neurones connect areas via pathways
Send and integrate information

Question 2

What is an example of how neurones work?

Answer 2

The thalamus receives information about pain from the body, and passes the information up to the cortex.

Question 3

When is the reward pathway activated?

Answer 3

When the individual receives or sees the possibility of positive reinforcement.

Question 4

how is information transmitted in the brain

Answer 4

an electrical impulse travels down the axon towards the terminal

the terminal makes a connection with the dendrite of neighbouring neurone where it transmits a neurochemical signal

Question 5

what happens as an electrical impulse arrives at the terminal

Answer 5

as an electrical impulse arrives at the terminal, it triggers vesicles containing a NT to move toward the terminal membrane

the vesicles fuse with the terminal membrane to release their contents

once inside the synaptic cleft, NT can bind to specific proteins called NT receptors on the membrane of a neighbouring neurone

Question 6

what are neuromodulators

Answer 6

Neighbouring neurones release compounds called neuromodulators which enhance or inhibit the effects of NT

Question 7

what is an example of neuromodulator

Answer 7

endorphin - binds to opiate receptors on the post-synaptic cell and thereby alters the effect of dopamine

Question 8

what is the link between dopamine and reward

Answer 8

Olds and Milner discovered that rats will increase lever presses when electric stimulation is delivered to septal areas of the brain

Question 9

what is the action of cocaine

Answer 9

powdered form is snorted
slow route:
nose -> heart -> lungs -> heart -> brain

freebase form (crack) can be smoked
rapid route:
lungs -> heart -> brain

the faster the brain effect, the more addictive the drug
if u experience the effects of the drug faster, it is more addictive

Question 10

what are the cocaine binding sites

Answer 10

cocaine reaches all areas of the brain but binds to:

VTA and nucleus accumbens (reward pathways)

caudate nucleus which may explain other effects such as increased repetitive beh (nail-biting)

Question 11

what is the action of cocaine

Answer 11

cocaine binds to brain sites such as the VTA and the nucleus accumbens that are rich in DA synapses

Question 12

what is the normal function of DA?

Answer 12

under normal circumstances, DA from inside the terminal is released into the synaptic space and binds to DA receptors

then it is taken up by uptake pumps back into the terminal

Question 13

what happens to DA function when cocaine is present

Answer 13

when cocaine is present, it binds to the uptake pumps and prevents them from transporting DA back into the terminal

more DA builds up in the synaptic space and causes a net increase in DA neurotransmission

Question 14

1. binge/intoxication

Answer 14

focused on the positive reinforcing effects of drugs - using drugs for its pleasurable effects

involved serotoning, opioid peptides and GABA

acute doses of drugs of abuse associated with decreased reward threshold = less stimulation required to experience pleasure, will need more of the drug to produce the same level of rewarding effects (tolerance)

Question 15

withdrawal/negative affect

Answer 15

chronic irritability, anxiety, depression, low motivation for natural reward

hypoactivation of dopaminergic pathways, increased brain reward threshold during acute withdrawal = greater stimulation needed to feel pleasure

Question 16

preoccupation/anticipation

Answer 16

bc of the withdrawal symptoms they are anticipating the next drug use

craving - thinking abt using the substance again

decrease self control and need to get rid of the withrawal symptoms