Neurobiology of Addiction Flashcards

Neuroimaging studies of individuals with addiction commonly show reduced glucose metabolism and blood flow in which brain region?

Answer: Prefrontal cortex

PET and fMRI studies consistently show hypofrontality (reduced prefrontal cortex activity) in addiction, correlating with impaired inhibitory control and decision-making.

Which stage of the addiction cycle is primarily associated with activation of the extended amygdala and CRF systems?

Answer: Withdrawal/negative affect

The withdrawal/negative affect stage involves extended amygdala and CRF system activation, producing anxiety, dysphoria, and negative emotional states that drive compulsive use.

The role of the hippocampus in addiction is best characterized as:

Answer: Encoding and contextual retrieval of drug-related memories that trigger craving

The hippocampus encodes episodic and contextual memories of drug use; these memories can be retrieved by environmental contexts, powerfully triggering craving and relapse.

Brain-derived neurotrophic factor (BDNF) in the context of addiction primarily:

Answer: Has complex, region-specific roles — promoting addiction in some circuits and resilience in others

BDNF has region-specific effects: in the VTA-NAc it promotes addictive behaviors, while in the medial prefrontal cortex it may confer resilience — making its role complex.

The concept of 'opponent process theory' as applied to addiction explains:

Answer: Why initial drug pleasure is followed by an opposing aversive state that grows with repeated use

Opponent process theory posits that the initial pleasurable 'A-process' is opposed by an aversive 'B-process' that strengthens over time, driving tolerance and withdrawal-motivated use.

Methamphetamine's neurotoxic effects on dopaminergic neurons are primarily mediated by:

Answer: Oxidative stress and excitotoxicity from massive dopamine and glutamate release

Methamphetamine causes massive dopamine release creating reactive oxygen species, combined with glutamate excitotoxicity, resulting in oxidative damage to dopaminergic axon terminals.

Epigenetic mechanisms in addiction, such as histone acetylation and DNA methylation, are clinically relevant because they:

Answer: Alter gene expression without changing DNA sequence, potentially transmissible across generations

Epigenetic changes alter gene expression patterns in addiction-related circuits without changing DNA sequence, can persist long-term, and may contribute to intergenerational transmission of addiction vulnerability.