Aging and memory for expected and unexpected objects in real-world settings.

Adult age differences in the consistency effect were examined in 3 experiments. The consistency effect refers to items inconsistent with expectations being better remembered than items consistent with expectations. Younger and older adults walked into an office room and viewed objects that varied in their consistency with expectation. Immediate and delayed recognition tests on item information (i.e., distractors were defined by their semantic identity) revealed that both age groups recognized unexpected items better than expected items. However, when recognition of token information was requested (i.e., distractors were defined by their physical appearance), younger adults, in contrast to older adults, exhibited consistency effects. Also, under divided attention, young adults revealed the same pattern of data as did elderly adults under full attention. The results are discussed in terms of capacity-related differences in distinctive encoding.     

Effects of Social Demand on Reports of Self-Monitored Blood Glucose in Adolescents with Type 1 Diabetes Mellitus

The purpose of this study was to test the hypothesis that social demand could substantially affect reports of self-monitored blood glucose (BG) in adolescents with insulin-dependent diabetes mellitus. Of 34 patients initially enrolled in the study, 10 were excluded because they did not bring any BG records with them to an outpatient clinic appointment. The remaining 24 patients were randomly assigned to either a low or high social demand condition that provided instructions for monitoring of BG for the week following the appointment. The subjects' BG records were quantified to provide frequency of measurement and mean reported BG for the week prior to and after the clinic visit. Five subjects did not return their BG records for the week following the intervention. The analyses were therefore based on the 19 subjects from whom complete records were obtained. The 12 subjects in the low social demand group and 7 subjects in the high social demand group were equivalent with regard to age, duration of diabetes, socioeconomic status, and glycosylated hemoglobin. Frequency of BG measurement was similar in both groups during both weeks. The mean BG value reported in the week prior to intervention was similar for the groups. However, analyses of the post-intervention BGs revealed that subjects in the low-demand group reported significantly higher BGs compared to pre-intervention and to subjects in the high-demand group. These findings suggest that self-monitoring and reporting of BG is a social behavior that is affected by the demand characteristics of the interpersonal patient-health provider relationship. Because optimal treatment planning for individuals with diabetes requires accurate BG records, care must be taken to interpret them in light of the social demand characteristics associated with clinical assessment.     

Age-related changes in working and reference memory performance and locomotor activity in the Wistar rat

Wistar rats of three age groups were tested in an automated tunnel-maze system of variable geometry to investigate whether changes in spontaneous locomotor activity and in learning and memory develop differentially or in a correlated fashion as a function of age. Senescent (30 months) as well as mature-adult (17 months) rats showed an age-correlated decline of locomotor activity as compared to the mature-young (5 months) group. Both working-memory (measured as within-trial arm discrimination performance) and reference-memory (measured as avoidance of "blind alley" visits) were severely affected in the senescent group, whereas the middle-aged animals suffered only from a working-memory deficit. The findings provide evidence that locomotor deficits do not necessarily interfere in the assessment of age-related changes in cognitive performance. Furthermore the results support the hypothesis that working and reference memory have different underlying physiological correlates and that these neuronal systems are differentially affected by the aging process.     

Listeriosis of the central nervous system in children beyond the neonatal period

Observations on three children with neurolisteriosis (one case of meningitis, two cases of meningoencephalitis, each Serovar 4 b), show that even after the neonatal period, listeriosis must not be ignored in the process of diagnosis and therapy. It is the bacteriological examination of the cerebrospinal fluid, together with the blood culture, and not clinical symptoms and serology that guarantee a timely diagnosis and therapy (ampicillin and gentamicin).     

Sleep in the dove Zenaida asiatica

Electrographic and behavioral observations were made in five adult birds of the genus Zenaida asiatica. Five different vigilance states were quantitated: (1) Active waking (Aw) was characterized by constant behavioral activity; the nuchal electromyogram was tonically active with bursts associated to movements. The electroencephalographic pattern was low voltage and high frequency. (2) Quiet waking (Qw) was characterized by diminished behavioral activity and the EEG pattern was similar to that of Aw. (3) Drowsiness (D) was characterized by behavioral calm. Frequency of cerebral activity diminished progressively, but there were short periods of desynchronization corresponding to brief awakenings. (4) Slow wave sleep (SWS); during this period there was behavioral rest and EEG pattern of continuous slow waves and the nuchal EMG was tonically reduced. Spindles of sleep were not observed. (5) Paradoxical sleep (SP), behaviorally characterized by phasic manifestations consisting of noddings originated by rapid falling down of head and bursts of rapid eye movements. EEG activity was like that of waking state. EMG activity was maintained at the same level as during SWS but sometimes it decreased lightly. Total atonie was not observed. Sleep percentages were higher when recordings were done during the nocturnal period.