Thinking and reward areas change connections differently in the motivation system during return to cocaine use

Cocaine-induced reinstatement leads to potentiated synaptic strength and increased spine head diameter in the nucleus accumbens.

• Increased synaptic strength was measured as a higher AMPA/NMDA current amplitude ratio in medium spiny neurons of the nucleus accumbens core after cocaine extinguishment.
• The diameter of dendritic spine heads in these neurons was also found to be larger following cocaine-induced reinstatement.
• Glutamatergic inputs from the prelimbic prefrontal cortex and dopamine from the ventral tegmental area are involved in the reinstatement process.
• Pharmacological inhibition of either the prelimbic prefrontal cortex or the ventral tegmental area prevented reinstatement of cocaine seeking.
• Inhibition of the prelimbic prefrontal cortex resulted in further increases in synaptic strength and spine diameter, contrasting with the effects of ventral tegmental area inactivation.

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