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Conflict is a ubiquitous feature of interpersonal relationships, yet many of these relationships preserve their value following conflict. Our ability to refrain from punishment despite the occurrence of conflict is a characteristic of human beings. Using a combination of behavioral and neuroimaging techniques, we show that prosocial decision-making is modulated by relationship closeness. In an iterated social exchange, participants were more likely to cooperate with their partner compared to an unknown person by accepting unfair exchanges. Importantly, this effect was not influenced by how resources were actually being shared with one’s partner. The medial prefrontal cortex (MPFC) was activated when the partner, rather than the unknown person, behaved unfairly and, in the same context, the MPFC demonstrated greater functional connectivity with the dorsal anterior cingulate cortex (DACC). MPFC–DACC connectivity was inversely associated with participants’ tendency to “forgive” their partner for unfairness as well as performance outside the scanner on a behavioral measure of forgiveness. We conclude that relationship closeness modulates a neural network comprising the MPFC/DACC during economic exchanges.
Normal aging is associated with a decline in different cognitive domains and local structural atrophy as well as decreases in dopamine concentration and receptor density. To date, it is largely unknown how these reductions in dopaminergic neurotransmission affect human brain regions responsible for reward-based decision making in older adults. Using a learning criterion in a probabilistic object reversal task, we found a learning stage by age interaction in the dorsolateral prefrontal cortex (dIPFC) during decision making. While young adults recruited the dlPFC in an early stage of learning reward associations, older adults recruited the dlPFC when reward associations had already been learned. Furthermore, we found a reduced change in ventral striatal BOLD signal in older as compared to younger adults in response to high probability rewards. Our data are in line with behavioral evidence that older adults show altered stimulus-reward learning and support the view of an altered fronto-striatal interaction during reward-based decision making in old age, which contributes to prolonged learning of reward associations.
There is increasing interest ill understanding the neural systems that mediate analogical thinking, which is essential for learning and fluid intelligence. The aim of the present study was to shed light on the cerebral correlates of geometric analogical processing and on training-induced changes at the behavioral and brain level. In healthy participants a bilateral fronto-parietal network was engaged in processing geometric analogies and showed greater blood oxygenation dependent (BOLD) signals as resource demands increased. This network, as well as fusiform and subcortical brain regions, additionally showed training-induced decreases in the BOLD signal over time. The general finding that brain regions were modulated by the amount of resources demanded by the task, and/or by the reduction of allocated resources due to short term training, reflects increased efficiency - in terms of more focal and more specialized brain activation - to more economically process the geometric analogies. Our data indicate a rapid adaptation of the cognitive system which is efficiently modulated by short term training based on a positive correlation of resource demands and brain activation.
Multitalker situations confront listeners with a plethora of competing auditory inputs, and hence require selective attention to relevant information, especially when the perceptual saliency of distracting inputs is high. This study augmented the classical forced-attention dichotic listening paradigm by adding an interaural intensity manipulation to investigate developmental differences in the interplay between perceptual saliency and attentional control during auditory processing between early and middle childhood. We found that older children were able to flexibly focus on instructed auditory inputs from either the right or the left ear, overcoming the effects of perceptual saliency. In contrast, younger children implemented their attentional focus less efficiently. Direct comparisons of the present data with data from a recently published study of younger and older adults from our group suggest that younger children and older adults show similar levels of performance. Critically, follow-up comparisons revealed that younger children's performance restrictions reflect difficulties in attentional control only, whereas older adults' performance deficits also reflect an exaggerated reliance on perceptual saliency. We conclude that auditory attentional control improves considerably from middle to late childhood and that auditory attention deficits in healthy aging cannot be reduced to a simple reversal of child developmental improvements.
The flexible learning of stimulus-reward associations when required by situational context is essential for everyday behavior. Older adults experience a progressive decline in several cognitive functions and show deficiencies in neuropsychological tasks requiring flexible adaptation to external feedback, which could be related to impairments in reward association learning. To study the effect of aging on stimulus-reward association learning 20 young and 20 older adults performed a probabilistic object reversal task (pORT) along with a battery of tests assessing executive functions and general intellectual abilities. The pORT requires learning and reversing associations between actions and their outcomes. Older participants collected fewer points, needed more trials to reach the learning criterion, and completed less blocks successfully compared to young adults. This difference remained statistically significant after correcting for the age effect of other tests assessing executive functions. This suggests that there is an age-related difference in reward association learning as measured using the pORT, which is not closely related to other executive functions with respect to the age effect. In human aging, structural alterations of reward detecting structures and functional changes of the dopaminergic as well as the serotonergic system might contribute to the deficit in reward association learning observed in this study. (C) 2004 Elsevier Ltd. All rights reserved
In addition to sensory decline, age-related losses in auditory perception also reflect impairments in attentional modulation of perceptual saliency. Using an attention and intensity-modulated dichotic listening paradigm, we investigated electrophysiological correlates of processing conflicts between attentional focus and perceptual saliency in 25 younger and 26 older adults. Participants were instructed to attend to the right or left ear, and perceptual saliency was manipulated by varying the intensities of both ears. Attentional control demand was higher in conditions when attentional focus and perceptual saliency favored opposing ears than in conditions without such conflicts. Relative to younger adults, older adults modulated their attention less flexibly and were more influenced by perceptual saliency. Our results show, for the first time, that in younger adults a late negativity in the event-related potential (ERP) at fronto-central and parietal electrodes was sensitive to perceptual-attentional conflicts during auditory processing (N450 modulation effect). Crucially, the magnitude of the N450 modulation effect correlated positively with task performance. In line with lower attentional flexibility, the ERP waveforms of older adults showed absence of the late negativity and the modulation effect. This suggests that aging compromises the activation of the frontoparietal attentional network when processing the competing and conflicting auditory information.