Drugs And The Brain (2)
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Transcript of Drugs And The Brain (2)
Drugs and the brainFrans Koopmans, MADe Hoop Foundation
Drugs and the brain
The Brain• The brain is highly organized into a
number of different regions with specialized functions
• Hindbrain (maintenance of life: breathing control, wakefulness)
• Midbrain (motivation, learning, reinforcing pleasurable behaviour)
• Forebrain (abstract thought, planning, associations of thoughts and memories)
Drugs and the brain
Drugs and the brain
The Brain
Drugs and the brain
The Brain – major regions
Drugs and the brain
The Brain – areas of the cerebral cortex
Drugs and the brain
The Brain – the reward system
Drugs and the brain
Neurons, Brain Chemistry and Neurotransmission
Drugs and the brain
Neurons, Brain Chemistry and Neurotransmission
Drugs and the brain
Neurons, Brain Chemistry and Neurotransmission
Drugs and the brain
Neurotransmitters• Communication in the brain through
chemical messengers (neurotransmitters)
• Neurotransmitters have specific structures and functions.
• Which chemical is released depends upon the type of neuron.
• Each specific neurotransmitter binds to a specific receptor (lock/key)
Drugs and the brain
Neurons, Brain Chemistry and Neurotransmission
Drugs and the brain
Neurons, Brain Chemistry and Neurotransmission
Drugs and the brain
Psychoactive substances• Psychoactive substances mimic the
effects of neurotransmitters or interfere or even block normal function
• PA substances that bind and enhance the function of receptors: agonists
• PA substances that block normal functioning: antagonists
Drugs and the brain
Drugs change the way Neurons communicate
Source: Science & Practice Perpectives (NIDA, april 2007)
Drugs and the brain
Drugs and the brain
Dependence• Dependence is the result of a
complex interaction of the physiological effects of substances on brain areas associated with motivation and emotion, combined with ‘learning’ about the relationship between substances and substance-related cues.
Drugs and the brain
Mesolimbic dopamine pathway• Many psychoactive substances
activate the mesolimbic dopamine pathway (located in the midbrain)
• Most strongly implicated in the dependence-producing potential of psychoactive substances
Drugs and the brain
Mesolimbic dopamine pathway (MDP)• MDP closely involved in motivational
processes• Motivation: allotment of attentional
and behavioral resources to stimuli in relation to their predicted consequences
• Incentives: stimuli that elicit a response on the basis of their predicted consequences
Drugs and the brain
Two important areas• Ventral Tegmental Area (VTA) – rich in
neurons containing dopamine (emotions, thoughts, memories, planning, executing behavior)
• Nucleus Accumbens (NAc) – related to motivation and learning, signalling the motivational value of stimuli
Drugs and the brain
Source: NIDA website http://www.drugabuse.gov/pubs/teaching
Mesolimbic dopamine pathway
Drugs and the brain
Major brain regions with roles in addiction
Source: Science & Practice Perpectives (NIDA, april 2007)
Drugs and the brain
Brain regions and function• The prefrontal cortex is the focal area for
cognition and planning. • The ventral tegmental area (VTA) and
nucleus accumbens (NAc) are key components of the brain’s reward system.
• The VTA, NAc, amygdala, and hippocampus are major components of the limbic system, which coordinates drives, emotions, and memories.
Drugs and the brain
Brain Imaging Techniques• Structural Magnetic Resonance
Imaging (MRI)• Functional MRI• Magnetic Resonance Spectroscopy
(MRS)• Positron Emission Tomography (PET)• Single Photon Emission Computed
Tomography (SPECT)
Drugs and the brain
Brain Imaging Techniques knowledge:
• Brain anatomy and tissue composition• Biochemical, physiological and
functional processes• Neurotransmitter activity• Energy utilization and blood flow• Drug distribution and kinetics
Drugs and the brain
Brain Imaging Techniques used in drug abuse research
Source: Science & Practice Perpectives (NIDA, april 2007)
Drugs and the brain
The Brain on cocaine
Drugs and the brain
The Brain on cocaine
Drugs and the brain
The Brain on opiates
Drugs and the brain
The Brain on THC
Drugs and the brain
Drugs of abuse all activate the reward system via increasing dopamine neurotransmission