, 2003; Nordahl et al., 2003; Salo et al., 2002; Valkow et al., 2001a; & Zickler, 2002). .
Researchers also identify possible relationships between specific neurocognitive impairments and the psychomotor functioning of methamphetamine abusers. Zickler (2002) and Kalechstein et al. (2003) were concerned with identifying the effects of cognitive and psychomotor impairments following short-term abstinence from methamphetamine. In contrast, Nordahl et al. (2003), Salo et al. (2002) and Volkow et al. (2001a) provide evidence of the long-term effects of methamphetamine abuse on dopamine transport systems, neurocognition, and psychomotor functioning.
Researchers use a variety of imaging techniques in order to determine the degree of neuronal damage in the brain of methamphetamine abusers. The most commonly used instrument for measuring dopamine transport activity in the brain is the positron emission tomography (PET) (Volkow et al., 2001a; Zickler et al., 2002). The PET involves an injection of chemical tracers into the bloodstream, where they then bind to dopamine transporters in the brain. The amount of dopamine in the brain is measured according to the strength of the signal detected from the tracers. Volkow et al. (2001b) used the PET to measure glucose metabolism in higher cortical and lower subcortical regions in the brain of methamphetamine abusers.
An additional imaging technique used to measure neuronal damage is the proton magnetic resonance spectroscopy (MRS) (Nordahl et al., 2003). It uses unique pulse sequences to identify areas of the brain containing certain types of neurotransmitters. It is a noninvasive technique very similar to an additional device used in neurotransmitter measurement known as magnetic resonance imaging (MRI). An enhanced version of the MRI, known as the perfusion MRI (pMRI), was used to confirm evidence of brain damage found using PET scans of methamphetamine abusers (Swan, 2003).