fMRI studies of associative encoding in young and elderly controls and mild Alzheimer's disease.

OBJECTIVE: To examine alterations in patterns of brain activation seen in normal aging and in mild Alzheimer's disease by functional magnetic resonance imaging (fMRI) during an associative encoding task. METHODS: 10 young controls, 10 elderly controls, and seven patients with mild Alzheimer's disease were studied using fMRI during a face-name association encoding task. The fMRI paradigm used a block design with three conditions: novel face-name pairs, repeated face-name pairs, and visual fixation. RESULTS: The young and elderly controls differed primarily in the pattern of activation seen in prefrontal and parietal cortices: elderly controls showed significantly less activation in both superior and inferior prefrontal cortices but greater activation in parietal regions than younger controls during the encoding of novel face-name pairs. Compared with elderly controls, the Alzheimer patients showed significantly less activation in the hippocampal formation but greater activation in the medial parietal and posterior cingulate regions. CONCLUSIONS: The pattern of fMRI activation during the encoding of novel associations is differentially altered in the early stages of Alzheimer's disease compared with normal aging.

Encoding novel face-name associations: a functional MRI study.

The process of forming new associations between previously unrelated items of information, such as a name and a face, likely requires the integration of activity within multiple brain regions. The hippocampus and related structures in the medial temporal lobe are thought to be particularly critical in binding together items of information. We studied eight healthy young subjects with functional magnetic resonance imaging (fMRI) during the encoding of novel face-name associations compared to viewing repeated face-name pairs. A consistent pattern of activation was observed in the hippocampus, pulvinar nucleus of the thalamus, fusiform and dorsolateral prefrontal cortices across individual subjects. The location of the activation within the hippocampus was more anterior than previously reported in studies using similar novel vs. repeated paradigms with stimuli that did not specifically require relational processing among unrelated items. These data suggest that the process of forming new face-name associations is supported by a distributed network of brain regions, and provide additional evidence for the essential role of the hippocampus in associative memory processes.

Juxtafacet cysts as a cause of low back pain.

A case of persistent low back pain occurring in association with facet joint synovial cysts is presented. A history of low back pain and negative plain radiographs illustrate the nonspecific nature of the problem these cysts cause. Magnetic resonance imaging (MRI) clearly demonstrates the presence of lumbar facet joint cysts. Our patient underwent a L5-S1 laminectomy prior to presenting with a new episode of low back pain. Workup, including computed tomography (CT) scan and MRI, confirmed the presence of bilateral synovial cysts at the L4-5 level. Our patient exhibited a partial clinical improvement after surgical excision of bilateral facet joint cysts.Intraspinal synovial or ganglion cysts of the facet joints are rarely diagnosed. They originate from the synovium of the facet articulation. They can be a source of low back pain1 and present an important diagnostic and therapeutic challenge. Their presence can be easily overlooked using standard radiological techniques2 which may only demonstrate nonspecific degenerative changes such as disc space narrowing and osteophytes. If the patient undergoes surgery and the cyst is not identified preoperatively, the patient may be left with persistent back pain. Computed tomography scan and myelogram have been shown to demonstrate cystic lesions with calcified walls typical of facet joint cysts.3,4 In our case MRI definitively identified what was suspected on the CT scan. It is proposed that MRI is also a valuable, if not better imaging technique of the identification of these cysts.