Interactive effects of APOE and CHRNA4 on attention and white matter volume in healthy middle-aged and older adults

In the present study, we investigated age-related changes in interactions between efficiency of neuronal repair mechanisms and efficiency of cholinergic neurotransmission in the context of attentional orienting. In addition, we explored white matter volume changes as possible neuronal underpinnings. A sample of 230 healthy middle-aged (53–64 years) and older (65–75 years) adults was genotyped for polymorphisms of APOE and CHRNA4, a nicotinic receptor subunit gene. Participants were administered a visuospatial attention task involving letter discrimination with location cues of varying validity. Genotype effects on white matter volume were also investigated in a subset of participants who received MRI scans. APOE interacted with CHRNA4, such that APOE-ε4 carriers who were also CHRNA4 TT homozygotes showed disproportionately slowed reaction time (RT) following invalid location cues. The interaction was stronger in the middle-aged participants than in the older participants. There was also a trend for individuals with combined APOE-ε4/CHRNA4 TT genotypes to show both lower white matter volume and slower overall RT on the attention task. The interaction of a neurotransmission gene (CHRNA4) and a susceptibility gene (APOE) suggests that the efficiency of neuronal repair mechanisms may modulate the cholinergic system to influence attentional function.     

On-line brain stimulation: Measurement of threshold of reinforcement

This program and interface for a small computer (PDP8/e) performs the following operations: generates and delivers constant current stimulation to the brain of an animal, monitors electrical resistance at the stimulating electrode, and calculates the threshold of reinforcement based upon the frequency of characteristic pauses in the animal’s responding.     

Neuropsychological performance in older insomniacs

ABSTRACT

The purpose of this study was to examine daytime performance in older adults fulfilling the diagnostic criteria for DSM-IV Insomnia, using a comprehensive battery of neuropsychological tests, and to compare these objective findings with measures of self-reported cognitive functioning. A total of 121 participants (69% women) with a mean age of 64.0 were part of a thorough neuropsychological examination at a University-based neuropsychological clinic in Western Norway. Twenty-five percent of the participants fulfilled the diagnostic criteria for insomnia. In sum, the insomnia patients were not different from the good sleepers on any neuropsychological test measure, and none of the results on the performance measures were associated with the sleep-related daytime complaints. However, the insomniacs did rate their subjective memory performance as significantly worse than the good sleepers, and they also reported more depressive symptoms. We conclude that DSM-IV defined insomnia was not associated with any performance based measure; only with self-reported symptoms.     

SWIFT: a dynamical model of saccade generation during reading

Mathematical models have become an important tool for understanding the control of eye movements during reading. Main goals of the development of the SWIFT model (R. Engbert, A. Longtin, & R. Kliegl, 2002) were to investigate the possibility of spatially distributed processing and to implement a general mechanism for all types of eye movements observed in reading experiments. The authors present an advanced version of SWIFT that integrates properties of the oculomotor system and effects of word recognition to explain many of the experimental phenomena faced in reading research. They propose new procedures for the estimation of model parameters and for the test of the model's performance. They also present a mathematical analysis of the dynamics of the SWIFT model. Finally, within this framework, they present an analysis of the transition from parallel to serial processing.     

What do we learn in psychoanalytic training?

Can one define the aims of psychoanalytic training that most analysts would agree upon? For more than a decade the EPF Working Party ‘End of Training Evaluation Project (ETEP)’ has worked on this issue. Summarizing results of this work the author describes a set of basic elements every developing analyst should have learned or internalized during his training. His assertion is that most analysts notwithstanding their theoretical orientation could agree upon these necessary requirements for a successful ending of psychoanalytic training. These elements are demonstrated in the ability to understand the emotional demand of a patient in every session and the often ensuing emotional storm, to appreciate and deeply understand the value of free association, to preserve a neutral stance, to think in terms of transference and countertransference, and to think conceptually about what is happening and what one is doing in the session.     

A dichotic listening study of attention control in older adults

The influence of age on attentional control of bottom-up processing was investigated with a dichotic-listening paradigm. The typical right-ear-advantage (REA) without specific attentional instructions was used as a measure of bottom-up processing (non-forced condition). Top-down attentional control was evaluated by instructing subjects to report only the right or left ear stimulus of the dichotic pair (forced-right, forced-left conditions). Both young and old participants showed a REA in the non-forced condition and an increased REA in the forced-right condition. The old group failed, however, to use attention to modulate the REA to the same degree as the younger participants in the forced-left condition. Only the young group showed a significant left ear advantage (LEA). The results are discussed in relation to cognitive decline in normal aging and in early stages of dementia.