Effects of transient, mild mood states on semantic memory organization and use: an event-related potential investigation in humans.

The effects of transient mood states on semantic memory organization and use were investigated using event-related potentials. Participants read sentence pairs ending with (1) the most expected word, (2) an unexpected word from the expected semantic category, or (3) an unexpected word from a different (related) category; half the pairs were read under neutral mood and half under positive mood. Under neutral mood, N400 amplitudes were smallest for expected items and smaller for unexpected items when these came from the expected category. In contrast, under positive mood, N400 amplitudes to the two types of unexpected items did not differ. Positive mood seemed to specifically facilitate the processing of distantly-related, unexpected items. The results suggest that transient mood states are associated with dynamic changes in how semantic memory is used on-line.

Neuropsychological impairment in human immunodeficiency virus-infection: implications for employment. HNRC Group. HIV Neurobehavioral Research Center.

Individuals infected with the human immunodeficiency virus-Type 1 (HIV-1), are at increased risk for neurobehavioral impairment, particularly in later stages of the disease. Even patients in the medically asymptomatic or minimally symptomatic stages of infection may show mild deficits on comprehensive neuropsychological (NP) test batteries, although the clinical significance of such deficits remains uncertain. The present study used vocational difficulties as markers of clinical significance of NP impairment. In a sample of 289 HIV-infected, nondemented men, those who evidenced NP impairment had a higher unemployment rate (p < .001) than did their unimpaired counterparts. In HIV-positive subjects who remained employed, NP impairment was strongly associated with subjective decreases in job-related abilities. Neither depression nor medical symptoms could explain the relationship between the NP impairment and employment problems. These results are consistent with previous studies investigating other neuropsychiatric disorders, which suggest that even mild NP impairment can interfere with employment status. From this standpoint, such impairment in HIV-infected persons may be described as "clinically significant."