ISSN : 1226-9654
Late-life depression(LLD) is overshadowed by the general physical symptoms of the elderly, making it difficult to diagnose and treatment accurately. In the rs-fMRI study, salience network is a suitable network to describe emotional control and goal-directed behavior processes related to depression symptoms, and is known to be an important network for therapeutic effects, but studies for depressed elderly people are lacking. In this study, we compared the resting-state of 18 LLD group (GDS M=21.78 SD=3.30) and 18 randomized control group(GDS M=8.78 SD=4.42). We used a network based statistic (NBS) for searching network dynamics within the salience network(intra/inter). Thus, connectivity within salience network(caudate-amygdala) was significantly lower in the depressed group, and connectivity between networks(insula-prefrontal cortex-lateral parietal cortex) was found to be contrary to the prior study. In addition, we used a graph theory analysis for identifying inconsistent network topology between groups, LLD group was found to be significantly lower in the small-worldness and clustering coefficient(salience network, default mode network, temporal lobe) although there were no differences between the two groups in characteristic path length. Reduced intra-network connectivity seems to be related to difficulties in behavior and emotion regulation, while reduced inter-network connectivity seems to reflect a reduction in goal-directed behavior rather than a negative reflection on the past. The results of this study suggest that there is intended to help neuropsychological understanding of the symptoms of depressed elderly people, and also help with treatment using TMS(transcranial magnetic stimulation) by examining areas of poor network connectivity and efficiency.
Human errors can cause various accidents which accompany massive loss of lives. In an effort to prevent such errors, it is necessary to identify behavioral characteristics of errors. The present study was conducted to identify behavioral characteristics of slips and mistakes that are conceptually classified error types in ergonomics. To this end, we compared between reaction times of error-related trials in the color-word Stroop task requiring selective attention and word-shape switching task requiring rule retrieval. The results indicated that reaction times were faster for the error trials than for the correct trials in the Stroop task, whereas those were slower for the error trials than for the correct trials in the switching task. In the both tasks, reaction times were slower for the post-error trials than the correct trials. These findings indicate that slips and mistakes can have different behavioral characteristics.
Choice blindness, the failure to notice mismatches between an intended choice and presented outcome, has mostly been documented in decision-making tasks focusing on preferences, opinions, and facial recognition. To expand upon the existing choice blindness literature, we investigated whether the effect occurs in a non-ambiguous decision-making situation. To test this, we examined if conspicuous mismatches were detected when a simple single feature was manipulated using unidimensional stimuli. In Experiment 1, participants were presented with two bars of differing length and were told to choose the longer bar. Afterwards, their selection was presented on screen and participants had to enter how much longer their selection was than the other. In a few trials, however, the relationship between choice and outcome was manipulated and participants received the bar they did not choose. Consistent with previous experiments, only 20% of the manipulations were detected. To make sure participants actually interacted with the stimuli, in Experiment 2, participants had to adjust the length of the chosen bar themselves. While detection rates rose, choice blindness was still existent. Experiment 3 investigated the effect of task-relevancy on choice blindness. Participants were more susceptible to choice blindness when a task-irrelevant feature was swapped rather than a task-relevant feature. The principal finding was that, though all accurately remembered the difference, most were unaware of the mismatch even when the sole feature was manipulated. Also, both task-relevancy and stimulus similarity moderated the effect, hinting that both top-down and bottom-up attention plays a role.