Drugs and Cognitive Performance
What are drugs?
• Natural or synthetic substances that produce physiological changes when taken into
the body.
• Not all substances that produce physiological changes are drugs
- Many drugs have psychoactive effects, i.e., produce changes in: Mood, Cognition
Experience
- They influence behaviour by altering activity at nervous system synapses.
Why do psychologists care about drugs?
- Introduce drugs to manipulate the activity of particular NTs.
- Note: NT =Neurotransmitter
- Examine effects on cognition
- Investigates biological basis of cognition.
- Many people use a drug of some type almost on a daily basis. E.g. Caffeine
How do drugs influence cognitive performance?
Why do people love drugs?
Types of Drugs (exam question)
1. Stimulants
Caffeine, Nicotine, Amphetamines, Ecstasy, Cocaine
2. Depressants
Alcohol, Barbiturates, Benzodiazepines
3. Hallucinogens
LSD, Cannabis, Magic mushrooms (psilocybin), ketamine,
phencyclidine (PCP)
4. Analgesics
Opiates (Heroin, opium, methadone, pethidine, morphine, codeine,
buprenorphine)
5. Anabolic steroids
Social VS illegal
Social drugs:
Caffeine
Alcohol
Nicotine
Cannabis
Illegal drugs include:
Heroin
Cocaine
,Amphetamines
Ecstasy
How drugs affect the nervous system: Action Potential
Drugs act on our synapses.
Synapses = A very narrow gap of about 20nm between neurons
NB
- NT made in presynaptic neuron stored in synaptic vesicles
- Post-synaptic neuron membrane Neuroreceptors.
- Agonist = Increases NT effect
- Antagonist = Reduces NT effect
Cholinergic Synapse
, Pre-synaptic neuron
Post-synaptic neuron
- Synapses with the NT acetylcholine = cholinergic synapses.
- Action potential arrives at presynaptic membrane.
- Voltage-gated calcium channels open calcium ions enter the presynaptic neuron.
Cholinergic Synapse
• Ions in synaptic vesicles fuse with the presynaptic membrane, releasing acetylcholine
into the synaptic cleft.
• Acetylcholine diffuses across the synaptic cleft and binds to specific neuroreceptor
sites in the post synaptic membrane.
• Sodium channels open.
• Sodium ions diffuse into the postsynaptic membrane causing depolarisation, which
may cause an action potential
• Acetylcholinesterase breaks down acetylcholine.
• The products diffuse back into the presynaptic neuron.
• Here, acetylcholine is resynthesised using adenosine -triphosphate (ATP) from the
mitochondria.
Drugs can alter:
Pre-synaptic events
E.g.
• Processes in axon
• NT synthesis
• NT storage
• NT release
Synaptic cleft or post-synaptic events
E.g.
• Inactivation/re-uptake mechanism
• Activation of receptor molecules
• Activity of second-messenger systems
The Dopaminergic Reward System
What are drugs?
• Natural or synthetic substances that produce physiological changes when taken into
the body.
• Not all substances that produce physiological changes are drugs
- Many drugs have psychoactive effects, i.e., produce changes in: Mood, Cognition
Experience
- They influence behaviour by altering activity at nervous system synapses.
Why do psychologists care about drugs?
- Introduce drugs to manipulate the activity of particular NTs.
- Note: NT =Neurotransmitter
- Examine effects on cognition
- Investigates biological basis of cognition.
- Many people use a drug of some type almost on a daily basis. E.g. Caffeine
How do drugs influence cognitive performance?
Why do people love drugs?
Types of Drugs (exam question)
1. Stimulants
Caffeine, Nicotine, Amphetamines, Ecstasy, Cocaine
2. Depressants
Alcohol, Barbiturates, Benzodiazepines
3. Hallucinogens
LSD, Cannabis, Magic mushrooms (psilocybin), ketamine,
phencyclidine (PCP)
4. Analgesics
Opiates (Heroin, opium, methadone, pethidine, morphine, codeine,
buprenorphine)
5. Anabolic steroids
Social VS illegal
Social drugs:
Caffeine
Alcohol
Nicotine
Cannabis
Illegal drugs include:
Heroin
Cocaine
,Amphetamines
Ecstasy
How drugs affect the nervous system: Action Potential
Drugs act on our synapses.
Synapses = A very narrow gap of about 20nm between neurons
NB
- NT made in presynaptic neuron stored in synaptic vesicles
- Post-synaptic neuron membrane Neuroreceptors.
- Agonist = Increases NT effect
- Antagonist = Reduces NT effect
Cholinergic Synapse
, Pre-synaptic neuron
Post-synaptic neuron
- Synapses with the NT acetylcholine = cholinergic synapses.
- Action potential arrives at presynaptic membrane.
- Voltage-gated calcium channels open calcium ions enter the presynaptic neuron.
Cholinergic Synapse
• Ions in synaptic vesicles fuse with the presynaptic membrane, releasing acetylcholine
into the synaptic cleft.
• Acetylcholine diffuses across the synaptic cleft and binds to specific neuroreceptor
sites in the post synaptic membrane.
• Sodium channels open.
• Sodium ions diffuse into the postsynaptic membrane causing depolarisation, which
may cause an action potential
• Acetylcholinesterase breaks down acetylcholine.
• The products diffuse back into the presynaptic neuron.
• Here, acetylcholine is resynthesised using adenosine -triphosphate (ATP) from the
mitochondria.
Drugs can alter:
Pre-synaptic events
E.g.
• Processes in axon
• NT synthesis
• NT storage
• NT release
Synaptic cleft or post-synaptic events
E.g.
• Inactivation/re-uptake mechanism
• Activation of receptor molecules
• Activity of second-messenger systems
The Dopaminergic Reward System
