Distinct and common cortical activations for multimodal semantic categories.

If semantic representations are based on particular types of perceptual features, then category knowledge that arises from multimodal sensory experiences should rely on distinct and common sensory brain regions depending on the features involved. Using a similarity-based generation-and-comparison task, we found that semantic categories activated cortical areas associated with taste and smell, biological motion, and visual processing. Fruit names specifically activated medial orbitofrontal regions associated with taste and smell. Labels for body parts and clothing activated lateral temporal occipitoparietal areas associated with perceiving the human body. More generally, visually biased categories activated ventral temporal regions typically ascribed to visual object recognition, whereas functional categories activated lateral frontotemporal areas previously associated with the representation of usage properties. These results indicate that semantic categories that are distinguished by particular perceptual properties rely on distinct cortical regions, whereas semantic categories that rely on similar types of features depend on common brain areas.

Perception of sports photographs: a multidimensional scaling analysis.

Some sports photographs are remarkable for how animate they appear, whereas others seem particularly static or frozen. To explore the aspects of still photographs that might produce a sense of action, 34 observers viewed all possible pairs of 14 previously published images depicting sports figures in action and were asked to judge their similarity under two conditions, image-focus (how similar are the images) or movement-focus (how similar is the type of movement). A separate group of observers also rated each image on eight scales. Multidimensional scaling analyses suggested that in the image-focus condition, subjects tended to organize their judgments around three general dimensions, e.g., on-ground versus off-ground, while in the movement-focus condition the subjects were more likely to cluster the images along the lines of the particular activity, throwing, running, or jumping. We discuss the problem of movement depiction in sports photographs and make suggestions for research on the effects of facial expressions, muscular strain, and amount of limb extension.

Myoclonus from selective dentate nucleus degeneration in type 3 Gaucher disease.

OBJECTIVE: To describe a case with a new genetic variant of type 3 Gaucher disease presenting with stimulus-sensitive and action myoclonus in the presence of selective dentate abnormalities. DESIGN: Clinical, pathologic, and molecular genetic studies. SETTING: Medical school departments. PATIENT: A 6-year-old girl with type 3 Gaucher disease experienced progressively crippling generalized stimulus-sensitive and action myoclonus. Repeated electroencephalographic examination did not show cortical activity associated with the myoclonus, suggesting its subcortical origin. Neuropathological examination revealed selective degeneration of the cerebellar dentate nucleus and dentatorubrothalamic pathway in the face of essentially complete lack of storage in the brain. Mutation analysis identified the following 2 mutant alleles: one with a V394L mutation and the other with the lesion RecTL (D409H + L444P + A456P + V460V), which resulted from a recombination event, with the pseudogene located 16 kilobases downstream from the structural gene. CONCLUSION: Given the restricted abnormalities, this genetically unique case provides insight into the pathogenesis of myoclonus and suggests a prominent role for the cerebellar dentate nucleus in its genesis.

Primary adrenal insufficiency manifesting as malignant lymphoma.

Primary adrenal insufficiency associated with a hematologic malignant neoplasm is a rare entity. Most malignant neoplasms with metastases to the adrenal gland are secondary to solid carcinomas of the lung and breast. A 55-year-old man was seen with clinical and biochemical evidence of primary adrenal insufficiency as the initial manifestation of his malignant lymphoma. At autopsy the architecture of both adrenal glands was completely effaced by malignant plasmacytoid cells. This case emphasizes that infiltrative lymphoma of the abdomen is a rare cause of primary adrenal insufficiency and may be the initial manifestation. Furthermore, it should be included in the differential diagnosis.