An alternate approach to imaging brain function in Alzheimer’s Disease uses activation imaging, in which subjects perform a cognitive task, such as a memory test, in comparison to a control or resting state, during scanning. These methods identify brain regions that show increased cerebral blood flow (CBF), which is tightly coupled to neural activity, during ongoing mental operations. In principle, brain regions with impaired neural activity will show less CBF when engaged in a task than those unaffected and have the potential for identifying deficits more sensitively. In practice, however, activation imaging is more complicated: first, PET ligands used in activation imaging, typically H 2 [15-O], have a short half life, necessary for experiments involving multiple conditions but producing images with significantly lower signal, (more…)

Positron Emission Tomography (PET) has proven to be a sensitive and specific tool for identifying functional brain changes in patients with AD as well as those in preclinical stages, including genetic risk and mild cognitive impairment (MCI). PET uses positron-emitting radionucleotides (commonly used isotopes include oxygen-15 [ 15 O], nitrogen-13 [ 13 N], carbon-11 [ 11 C], and fluorine-18 [ 18 F]) to monitor both glucose metabolism and blood flow after these molecules enter the central venous system and are detected by crystal scintillation detectors in the Positron Emission Tomography (PET) scanner. (more…)

Addiction is more than frequent drug use. Recent scientific research provides strong evidence that drugs not only interfere with normal brain functioning but also have long-term effects on brain metabolism and activity. Those addicted to drugs experience compulsive drug craving and cannot quit by themselves. Treatment of dementia is necessary to end this compulsive behavior. (more…)