[Bioundgrd] Physics colloquium tomorrow (May 6): Brain Imaging

[Stu Dietz]

>Imaging the Addicted Brain: From Molecules to Behavior
>Dr. Nora Volkow
>Director, National Institute on Drug Abuse
>
>Thursday, 5/6/2004
>Time: 4:15pm
>Place: Room 10-250
>
>
>ABSTRACT:
>Imaging technologies such as positron emission tomography (PET) and 
>magnetic resonance imaging (MRI) have provided tools and have 
>identified new challenges to study the effects of drugs of abuse on 
>the human brain.  Imaging studies have revealed neurochemical and 
>functional changes in the brains of drug-addicted subjects that 
>differentiate them from drug- intoxicated subjects and provide new 
>insights into the mechanisms underlying addiction. 
>
>Neurochemical studies have shown that the large and rapid 
>drug-induced increases in dopamine found in the brain during drug 
>intoxication are associated with the reinforcing effects of abused 
>psychoactive drugs.  By contrast, after chronic drug abuse and 
>during withdrawal, brain dopamine function is markedly decreased and 
>these decreases are associated with dysfunction of prefrontal brain 
>regions (including orbitofrontal cortex and cingulate gyrus).  Such 
>changes have been shown to result in decreased sensitivity to 
>natural reinforcers (dopamine also mediates the reinforcing effects 
>of natural reinforcers) and in disruption of frontal cortical 
>functions, such as inhibitory control (ability to control impulses 
>or desires) and salience attribution (ability to assign reinforcing 
>value to stimuli). 
>
>Functional imaging studies have shown that during drug intoxication 
>or during craving, these frontal regions get activated as part of a 
>complex pattern that includes brain circuits involved with reward 
>(nucleus accumbens), motivation (orbitofrontal cortex), memory 
>(amygdala and hippocampus), and cognitive control (prefrontal cortex 
>and cingulate gyrus). This presentation will focus on some recent 
>findings from neuroimaging studies that have broadened our 
>understanding of drug abuse and addiction in particular, and brain 
>science in general.
>
>Physics Colloquium Series
>Physics Headquarters, 6-113
>(617)253-6259 FAX (617)253-8554
><http://web.mit.edu/physics/>http://web.mit.edu/physics/


-- 
Stu Dietz
Biology Education Office, Rm. 68-120
Massachusetts Institute of Technology
77 Massachusetts Ave.
Cambridge, MA  02139

Phone (617) 252-1783
Fax (617) 258-9329
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