Brain

THC Hampers Spatial Memory Development in Young Monkeys

Adolescent monkeys that were exposed to THC fell progressively further behind THC-free monkeys in their ability to recall the location of an object after a brief delay.

Prefrontal Cortex Stimulation Stops Compulsive Drug Seeking in Rats

Researchers have shut down laboratory rats’ compulsive cocaine seeking by stimulating an area of the animals’ prefrontal cortex (PFC). The finding raises the possibility that stimulating neurons in this brain area may weaken or break cocaine’s grip on the behavior of people who are addicted to the drug. Dr. Billy Chen, Dr. Antonello Bonci, and colleagues at the NIDA Intramural Research Program (IRP) in Baltimore, Maryland, conducted experiments to better understand the significance of reduced PFC activity in drug abuse and addiction. Their findings demonstrate that cocaine dampens neuronal

Deep Brain Stimulation Attenuates Rats’ Responses to Heroin

High-frequency electrical stimulation of neurons deep in the brain can reduce rats’ relapse-like behavior and motivation to take heroin. The finding strengthens hope that deep brain stimulation might offer a new treatment alternative for opioid addiction, particularly for patients who have not benefited from other treatments.

Methamphetamine Evokes and Subverts Brain Protective Responses

NIDA-supported researchers have produced brain images demonstrating that structures in an area called the striatum expand in volume during early methamphetamine abuse, then regress toward normal. The investigators believe their findings likely are attributable to neuroprotective cells in the brain mounting an initial attempt to counteract the drug's toxic effects, which continued exposure subsequently overwhelms. In a related result, scientists working with mice have produced evidence that methamphetamine may prompt cells that normally serve neuroprotective functions to instead attack healthy

Narrative of Discovery: Can Magnets Treat Cocaine Addiction?

Two researchers share their reasons for researching transcranial magnetic stimulation (TMS) for treating cocaine addiction, and describe challenges to moving forward this potentially promising therapy.

Why Take a Drug That No Longer Gives Pleasure?

In mice, a cocaine-induced imbalance in the activity of two key populations of neurons in the reward system persists for a longer period after repeated exposure to the drug. For long-term users, this change could both weaken the cocaine “high” and strengthen the compulsion to seek the drug.

Animation: The Rise and Fall of the Cocaine High

View the animation Research indicates that the speed with which a drug of abuse enters and leaves the brain affects how “high” it makes users feel. “Highs” tend to be more intense when a drug abruptly floods the brain and then rapidly washes out. This observation is important because the intensity of the “high” influences how much users will want to repeat the experience—hence, how addictive the drug is. Accordingly, “fast-in, fast-out” drugs tend to be more addictive. Cocaine is a highly addictive drug. This animation shows the rapid passage of the drug through the brain. It demonstrates that

Dr. Antonello Bonci Q & A: Lighting Up the Brain To Shut Down Cocaine Seeking

Dr. Antonello Bonci, Scientific Director of NIDA’s Intramural Research Program (IRP), talks about switching off animals’ compulsive cocaine seeking by optogenetically activating the prefrontal cortex, and the implications of this work for people. His comments supplement a NIDA Notes article. NIDA Notes: What did your study show? Dr. Antonello Bonci, NIDA IRP Dr. Bonci: We found that we could turn rats into compulsive cocaine seekers by shutting down activity in the prefrontal cortex (PFC) and make them quit seeking cocaine by reactivating the PFC. This suggests that there is a switch-point in

Methamphetamine Alters Brain Structures, Impairs Mental Flexibility

A new study adds to the copious existing evidence that chronic exposure to addictive drugs alters the brain in ways that make quitting difficult. NIDA-supported researchers showed that, in monkeys, methamphetamine alters brain structures involved in decision-making and impairs the ability to suppress habitual behaviors that have become useless or counterproductive. The two effects were correlated, indicating that the structural change underlies the decline in mental flexibility. Human chronic methamphetamine users have been shown to differ from nonusers in the same ways that the post-exposure

Stimulants in “Bath Salts” Produce Effects Similar to MDMA

Mephedrone and methylone, two stimulants commonly found in designer drugs such as “bath salts,” act on the brain much like methylenedioxymethamphetamine (MDMA, Ecstasy). According to recent studies, the two may be addictive, but may not have the same propensity for causing toxicity as MDMA. Figure 1A and 1B. Mephedrone and Methylone Increase Extracellular Serotonin and Dopamine Direct measurements of neurochemical release in the nucleus accumbens of living rats show that the higher the dose of mephedrone and methylone, the greater the increase in extracellular dopamine and serotonin levels

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