Amygdala oscillations and the consolidation of emotional memories

The amygdala receives multi-modal sensory inputs and projects to virtually all levels of the central nervous system. Via these widespread projections, the amygdala facilitates consolidation of emotionally arousing memories. How the amygdala promotes synaptic plasticity elsewhere in the brain remains unknown, however. Recent work indicates that amygdala neurons show theta activity during emotional arousal, and various types of oscillations during sleep. These synchronized neuronal events could promote synaptic plasticity by facilitating interactions between neocortical storage sites and temporal lobe structures involved in declarative memory.     

Models of habituation in infancy

Research on infant cognition using habituation methods has sparked considerable controversy in recent years. At the core of the debates is the issue of whether infants have early (and possibly innate) conceptual understandings. This article reviews a range of computational models of habituation that might provide insights into such discussions. The models are assessed against key behavioral and neural features of habituation: temporal unfolding, exponential decrease, familiarity-to-novelty shift, habituation to repeated testing, discriminability of habitual items, selective inhibition and cortical-subcortical interactions. The review suggests that current models fail to offer comprehensive explanations of the behavioral phenomena.     

A test of parafoveal‐on‐foveal effects with pairs of orthographically related words

One of the main controversies in the field of eye movements in reading concerns the question of whether the processing of two adjacent words in reading occurs in sequence, or in parallel. To distinguish between these views, the present experiment tested the presence of parafoveal‐on‐foveal effects with pairs of orthographically related words (or neighbours that differed by a single letter) in a controlled but reading‐like situation. Results revealed that fixation times on a foveal target word were shorter when the target was accompanied by an orthographically similar parafoveal word than when the parafoveal word was dissimilar. Furthermore, the size of the effect tended to vary with both the relative frequency of target and parafoveal words, and the position of the critical letter. These results were interpreted in the framework of a pure parallel processing hypothesis, where the processing of adjacent words is only limited by visual acuity, and the respective lexical properties of the foveal and parafoveal words.     

Neuroimaging of mental imagery: An introduction

Adaptive mechanisms to protect cognitive performance under stressors through compensation in energy investment have previously received much research attention. However, stressors have also often been found to substantially reduce both performance and investment. The mechanisms underlying this dual negative effect are still unclear. This study tested the hypothesis that stressors can immediately hamper performance, which in turn reduces energy investment in later phases. In an experiment (N=103), we compared control and stressor conditions (noise or time pressure), investigating the effects of stressors on performance and information-sampling investment (as behavioural measure of energy investment) in two phases of a judgement task. The results showed an instant negative effect of stressors on performance and a delayed negative effect on information-sampling investment. Furthermore, impaired initial performance predicted the decline in investment over time. Finally, the effects of stressors on investment decline were partially mediated through initial performance level. The present findings contribute to theories aiming to explain the relationship between hampered performance and motivational losses.     

Programming Precision in Repetitive Tapping

The present paper reports an experiment using the Fitts’ tapping paradigm. It is concerned with a comparison of movement times and accuracy during blind and visual repetitive tapping. A blind condition was used to investigate rapid aiming movements under motor program control, whilst visual aiming was used to assess the role of visual feedback for control purposes. Subjects in the blind conditions were able to replicate the amplitude specifications of the task, whereas effective target width was constant for a set amplitude and did not reflect specified target width. Subjects, furthermore, responded more rapidly when tapping blind. These results are discussed in terms of the magnitude of forces being attempted as a result of performing a set amplitude, and the role of visual feedback.     

The double step analysis of rapid manual aiming movements

The present paper examines the control principles underlying rapid manual tracking responses to horizontal double-step stimuli. The paper reports an experiment concerned with responses made to step-stimuli presented in quick succession. The amplitude of the second-step was varied between the initial step-position and the home-base. Double-step response parameters were analysed as a function of the determinant time interval (D) between the second step and the onset of the initial response. The initial response amplitude was observed to vary as a function of D. Amplitude transition functions were constructed representing the transition of the initial response amplitude between the two step positions; their slopes, furthermore, depended on the amplitude of the second target step. No delays in the initial reaction time with the interstimulus interval were observed. Minor delays to the onset of a corrective response were observed. These delays were in part related to a movement time constraint that is independent of any limitations in central processing capacity. The present findings for the manual control system are compared to double-step tracking analyses of the oculomotor control system.     

Foveal processing and word skipping during reading

An eyetracking experiment is reported examining the assumption that a word is skipped during sentence reading because parafoveal processing during preceding fixations has reached an advanced level in recognizing that word. Word n was presented with reduced contrast, with case alternation, or normally. Reingold and Rayner (2006) reported that, in comparison to the normal condition, reduced contrast increased viewing times on word n but not on word n+1, whereas case alternation increased viewing times on both words. These patterns were reflected in the fixation times of the present experiment, but a striking dissociation was observed in the skipping of word n+1: The reduced contrast of word n decreased skipping of word n+1, whereas case alternation did not. Apart from the amount of parafoveal processing, the decision to skip word n+1 is also influenced by the ease of processing word n: Difficulties in processing word n lead to a more conservative strategy in the decision to skip word n+1.     

Life satisfaction shows terminal decline in old age: longitudinal evidence from the German Socio-Economic Panel Study (SOEP)

Longitudinal data spanning 22 years, obtained from deceased participants of the German Socio-Economic Panel Study (SOEP; N = 1,637; 70- to 100-year-olds), were used to examine if and how life satisfaction exhibits terminal decline at the end of life. Changes in life satisfaction were more strongly associated with distance to death than with distance from birth (chronological age). Multiphase growth models were used to identify a transition point about 4 years prior to death where the prototypical rate of decline in life satisfaction tripled from -0.64 to -1.94 T-score units per year. Further individual-level analyses suggest that individuals dying at older ages spend more years in the terminal periods of life satisfaction decline than individuals dying at earlier ages. Overall, the evidence suggests that late-life changes in aspects of well-being are driven by mortality-related mechanisms and characterized by terminal decline.     

Input monitoring and response selection as components of executive control in pro-saccades and anti-saccades

Several studies have shown that anti-saccades, more than pro-saccades, are executed under executive control. It is argued that executive control subsumes a variety of controlled processes. The present study tested whether some of these underlying processes are involved in the execution of anti-saccades. An experiment is reported in which two such processes were parametrically varied, namely input monitoring and response selection. This resulted in four selective interference conditions obtained by factorially combining the degree of input monitoring and the presence of response selection in the interference task. The four tasks were combined with a primary task which required the participants to perform either pro-saccades or anti-saccades. By comparison of performance in these dual-task conditions and performance in single-task conditions, it was shown that anti-saccades, but not pro-saccades, were delayed when the secondary task required input monitoring or response selection. The results are discussed with respect to theoretical attempts to deconstruct the concept of executive control.     

Mood in foreign exchange trading: Cognitive processes and performance

This paper examines the effects of mood on the behavior of traders or decision makers in financial markets. Based on a review of the psychological theories and empirical findings which relate mood to decision making and information processing, we derive hypotheses with respect to the impact of good, neutral, and bad moods on the behavior of traders. Two experiments (N=66 and 72) were conducted on an Internet platform which simulated foreign exchange trading based on historical market data. The first experiment manipulated mood using feedback and music whereas the second one asked subjects to read mood-laden statements. It was found that traders in a good mood had an inferior trading performance (losing money) compared to those in a neutral or bad mood (making profit). This is because traders in a good mood made less accurate decisions than those in neutral or bad moods. Those in a bad mood were the most accurate in their decisions but behaved conservatively in their trading. Subjects in a good mood tended to make less accurate decisions though they spent on average at least the same time as the other subjects on information processing and decision-making. They also were over-confident taking unwarranted risks. The studies concluded with insights concerning the effects of mood on choice of trading strategies.