Effects of post-encoding wakeful rest and study time on long-term memory performance

Recent work shows that post-encoding wakeful rest, in contrast to a cognitive task delay period, supports memory performance. The present study aimed at investigating whether study time modulates the impact of post-encoding rest on delayed memory performance. Healthy young adults were allocated to one of two “study time” groups (fixed-paced vs. self-paced). Participants encoded two word lists. After immediate recall of one word list, participants wakefully rested for 8?min, after the other, they performed a visual problem solving task. A delayed recall took place at the end of the experimental session (Experiment 1) and again after 7 days (Experiment 1?+?2). We found that participants in the self-paced group outperformed those in the fixed-paced group. In Experiment 1, participants showed higher memory performances after 7 days in the resting condition independent of study time. No significant differences between post-encoding (rest vs. problem solving) and study time conditions were found in Experiment 2. Combined analyses of both experiments revealed that an additional recall (Experiment 1) supported memory retention in both post-encoding conditions. Our findings suggest that resting is beneficial over the long term, but only when the encoded information is repeatedly retrieved at the end of a learning session.     

Hippocampal PKA/CREB pathway is involved in the improvement of memory induced by spermidine in rats

Spermidine (SPD) is an endogenous polyamine that modulates N-methyl-D-aspartate (NMDA) receptor function, and has been reported to facilitate memory formation. In the current study we determined whether or not the PKA/CREB signaling pathway is involved in SPD-induced facilitation of memory of inhibitory avoidance task in adult rats. The post-training administration of the cAMP-dependent protein kinase (PKA) inhibitor, N-[2-bromocinnamylamino)ethyl]-5-isoquinoline sulfonamide [H-89, 0.5 ρmol intrahippocampal (ih)] or the antagonist of the NMDA receptor polyamine-binding site (arcaine, 0.02 nmol ih) with SPD (0.2 nmol ih) prevented memory improvement induced by SPD. Intrahippocampal administration of SPD (0.2 nmol) facilitated PKA and cAMP response element-binding protein (CREB) phosphorylation in the hippocampus 180 min, but not 30 min, after administration, and increased translocation of the catalytic subunit of PKA into the nucleus. Arcaine (0.02 nmol) and H-89 (0.5 ρmol) prevented the stimulatory effect of SPD on PKA and CREB phosphorylation. These results suggest that memory enhancement induced by the ih administration of SPD involves the PKA/CREB pathways in rats.     

The influence of rumination and defensiveness on negative affect in response to experimental stress

Previous experiments investigating the influence of rumination on negative affect have often manipulated the timing and content of rumination, which may be problematic as rumination is phenomenologically experienced as uncontrollable. In the present experiment, rumination was not manipulated, but measured as an individual tendency before the experiment. Furthermore, it was tested whether defensiveness would reduce the higher degree of negative affect often associated with rumination. Fifty-six participants completed questionnaires measuring rumination and defensiveness and participated in a phrase completion task, rating negative affect before and after the task. Correlational analyses showed that rumination was positively associated (p < 0.05) with affect responses (r range = 0.35-0.61), whereas defensiveness was negatively associated with affect responses (r range =-0.27-0.32). Four groups of high and low rumination and defensiveness scorers were created using median splits. An ANOVA showed that scoring high on defensiveness did not reduce the negative affect experienced by high ruminating participants.     

Repressive coping style and autonomic reactions to two experimental stressors in healthy men and women

Autonomic and affective responses to two different stress tasks were measured in 45 males and 74 females, categorized as repressive, true low-anxious, true high-anxious, and defensive high-anxious. Electrodermal activity (EDA) was used as a measure of sympathetic activity and the high frequency (HF) spectral component of heart rate variability as a measure of parasympathetic activity. Contrary to our predictions, reactivity of repressors did not differ from the reactivity of true low-anxious participants. The results draw attention to previous inconsistent findings within the literature on repressive coping style and autonomic nervous system dysregulation. It is suggested that future research could benefit from the use of more consistent operationalizations of the repressive coping construct and from comparing alternative measures of repressive coping within the same study.     

Categorical perception of face identity in noise isolates configural processing.

Neuropsychological evidence suggests that face recognition based on configural (holistic) information can occur in isolation from recognition based on local feature cues. The present study shows that configural processing can be isolated experimentally in normal subjects. A phenomenon is reported that exists only for upright whole faces, namely categorical perception (CP) of face identity in noise. Three discrimination tasks (ABX, better likeness, and similarity ratings) were used to test for perceptual distortion across the category boundary predicted from binary classification of face morphs. Noise was added such that any single local region provided unreliable cues to identity. Under these conditions, CP was found for upright faces but not for inverted faces or single features, even with more than 10,000 trials. The CP-in-noise signature phenomenon was then used to show that configural processing survives image plane rotations of 45 degrees-90 degrees.     

The factor structure of the Inventory of Parent and Peer Attachment (IPPA): A survey of Italian adolescents

Despite the intensive use of the Inventory of Parent and Peer Attachment (IPPA), a measure of attachment which centres on individual differences in adolescents and their ability to evaluate their relationships with parents and peers, the factor structure of the inventory requires further investigation. This study of 1059 Italian adolescents compared the three models which are discussed in the literature: the one-factor model (attachment security), the two-factor model (trust-communication and alienation) and the three-factor model (trust, communication and alienation), and examined the influences of age and gender on the IPPA’s scores. Our findings provide support for the reliability of the latest and longer version of the IPPA (75-item). Factor analysis showed that the three-factor model had the best fit, although the three dimensions are strongly interrelated. Sixteen year olds had lower attachment security to their fathers than the results of the other adolescent age groups. Males reported lower alienation scores than females in the paternal form, while females had higher attachment security, trust and communication scores than males in the peers form.     

Time of day affects episodic memory in older adults

The neuropsychological test scores of 2030 cognitively normal older adults were examined to evaluate performance patterns as they related to time of day (TOD) at which testing was initiated. Multiple regression analyses were used to examine the association of TOD with scores on seven neuropsychological tests used in the clinical evaluation of dementia. Episodic memory performance was significantly related to TOD, while memory span and verbal fluency were not. Best performance occurred during early morning hours and late afternoon; worst performance occurred mid-day (i.e., noon). These findings may have implications for clinical assessment, the design of research on dementia, and the daily functioning of older adults.     

EEG alpha reactivity and extraversion-introversion

Spectral characteristics of spontaneous EEG and characteristics of the alpha attenuation response (AAR) induced by acoustic stimulation, were analyzed for two groups of subjects selected on the basis of their scores on the extraversion-introversion scale of the Eysenck Personality Questionnaire. While no significant differences were found in basic alpha rhythm, significant differences were manifested in the AAR characteristics. Extraverted subjects habituated to the auditory stimulus while introverts did not. Introverts were generally more responsive to stimulation. The results are discussed in relation to the arousability model proposed by Eysenck and Gray, verifying the relationships with typological dimensions of Superior Nervous Activity, elaborated by the Soviet school.