Navigation Links
New clue to cocaine addicts' quirky behavior

Researchers working with rats have zeroed in on the brain circuitry mechanism whose disruption contributes to the impulsive behavior seen in users of cocaine as well as other psychostimulant drugs. The same circuitry has been implicated in such disorders as schizophrenia, depression, and post-traumatic stress disorder, wrote the researchers.

Yukiori Goto and Anthony A. Grace of the University of Pittsburgh described their findings in the July 21, 2005, issue of Neuron. In their studies, they sought to understand the effects of cocaine sensitization on the connections between two higher brain regions--the prefrontal cortex and the hippocampus--and the nucleus accumbens, which is the region in the limbic system involved in processing reward behavior. The prefrontal cortex is involved in processing information, and the hippocampus is involved in learning and memory.

The connections to the nucleus accumbens seem to be bidirectional, said the researchers, and the interactions with the prefrontal cortex and hippocampus could affect the "plasticity" of connections in the neurons of the nucleus accumbens. This means that disruptions to the normal connections could affect behavior.

The researchers' electrophysiological studies of the effects of cocaine on this circuitry demonstrated that the drug did disrupt this normal plasticity. They found that the cocaine induced abnormal enhancement of neuronal connections--a phenomenon called long-term potentiation (LTP).

The researchers also performed behavioral studies on the cocaine-sensitized rats, to explore the behavioral effects of this disruption. In these studies, they placed the rats in a plus-shaped maze. The rats were taught that in response to a visual cue they should turn left or right toward one arm or the other of the maze to obtain a piece of cereal.

Goto and Grace found that, while the cocaine-sensitized rats learned the correct response strategy faster than normal rats, they wer e significantly less able to change strategies when they were required to ignore the cue and always make a left or right turn to receive the reward.

"Thus, although abnormally induced LTP by psychostimulants at limbic inputs might not interfere with learning a response strategy, it may reduce the capacity of these animals to consider alternate response strategies," concluded Goto and Grace. "In this way, the disruption of synaptic plasticity by cocaine sensitization may contribute to the affective- and context-inappropriate impulsive behaviors that are characteristic of drug addiction."

This work was supported by USPHS and National Alliance for Research on Schizophrenia and Depression Young Investigator Award. Y.G. is NARSAD Essel Investigator.

Goto and Grace: "Dopamine-dependent Interactions between Limbic and Prefrontal Cortical Plasticity in the Nucleus Accumbens: Disruption by Cocaine Sensitization" Publishing in Neuron, Vol. 47, July 21, 2005, pages 255?66. DOI 10.1016/j.neuron.2005.06.017. www.neuron.org


'"/>

Source:Cell Press


Related biology news :

1. Portable cocaine sensor developed at UC Santa Barbara
2. High resolution snapshots detail dynamics of a cocaine antibody
3. Genetically altered mice no longer like cocaine
4. High-tech research shows cocaine changes proteins and brain function
5. Altered perception of reward in human cocaine addiction
6. Scientists design simple dipstick test for cocaine, other drugs
7. Prenatal cocaines lasting cellular effects
8. Rensselaer researchers develop approach that predicts protein separation behavior
9. Scientists uncover new clues about brain function in human behavior
10. Single gene is genetic switch for fly sexual behavior
11. Using the genomic shortcut to predict bacterial behavior
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:10/4/2017)... , Oct. 4, 2017  GCE Solutions, a global clinical research ... and document anonymization solution on October 4, 2017. Shadow is designed ... to comply with policy 0070 of the European Medicines Agency (EMA) ... ... Solutions ...
(Date:8/15/2017)... , Aug. 15 2017   ivWatch LLC , a ... intravenous (IV) therapy, today announced receipt of its ISO 13485 Certification, ... by the International Organization for Standardization (ISO®). ... ivWatch Model 400 Continuous Monitoring device for the early ... "This is an ...
(Date:6/30/2017)... , June 30, 2017 Today, American ... and supplier of face and eye tracking software, ... Product provider program. "Artificial intelligence ... way to monitor a driver,s attentiveness levels while ... being able to detect fatigue and prevent potential ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... ... it will be hosting a Webinar titled, “Pathology is going digital. Is your ... on digital pathology adoption best practices and how Proscia improves lab economics and ...
(Date:10/11/2017)... , ... October 11, 2017 , ... ... the implantation and pregnancy rates in frozen and fresh in vitro fertilization ... progesterone and maternal age to IVF success. , After comparing the results from ...
(Date:10/10/2017)... ... October 10, 2017 , ... ... program has won a US2020 STEM Mentoring Award. Representatives of the FirstHand program ... in Volunteer Experience from US2020. , US2020’s mission is to change the trajectory ...
(Date:10/10/2017)... ... October 10, 2017 , ... ... process optimization firm for the life sciences and healthcare industries, announces a presentation ... San Francisco. , The presentation, “Automating GxP Validation for Agile Cloud Platforms,” will ...
Breaking Biology Technology: