by studies that show brain activity in the same location when a visual memory is encoded and retrieved, and lexical memory in a different location. Visual memory areas were mostly located within the bilateral extrastriate visual cortex. Mental disorders Levels-of-processing effects interact in various ways with mental disorders. In particular, levels-of-processing effects appear to be strengthened in patients with age-related memory degradation, selectively strengthened in panic disorder patients, unaffected in Alzheimer's disease patients, and reversed in autistic patients. Age-related memory degradation Memory encoding strength derived from higher levels-of-processing appears to be conserved despite other losses in memory function with age. Several studies show that, in older individuals, the ability to process semantically in contrast with non-semantically is improved by this disparity. Neural imaging studies show decreased left-prefrontal cortex activity when words and images are presented to older subjects than with younger subjects, but roughly equal activity when assessing semantic connections. Panic disorders Panic disorders appear to modify levels-of-processing by increasing ability to recall words with threatening meanings over positive and neutral words. In one study, both implicit (free recall) and explicit (memory of emotional aspects) memorization of word lists were enhanced by threatening meanings in such patients. Alzheimer's disease Modern studies show an increased effect of levels-of-processing in Alzheimer patients. Specifically, there is a significantly higher recall value for semantically encoded stimuli over physically encoded stimuli. In one such experiment, subjects maintained a higher recall value in words chosen by meaning over words selected by numerical order. Autism In autistic patients, levels-of-processing effects are reversed in that semantically presented stimuli have a lower recall value than physically presented stimuli. In one study, phonological and orthographic processing created higher recall value in word list-recall tests. Other studies have explicitly found non-semantically processed stimuli to be more accurately processed by autistic patients than in non-autistic patients. No clear conclusions have been drawn as to the cause of this oddity. References Memory Memory biases