Fronto-parietal activity has been frequently observed in fMRI and PET studies of attention, working memory, and episodic memory retrieval. Several recent fMRI studies have also reported fronto-parietal activity during conscious visual perception. A major goal of this review was to assess the degree of anatomical overlap among activation patterns associated with these four functions. A second goal was to shed light on the possible cognitive relationship of processes that relate to common brain activity across functions. For all reviewed functions we (...) observed a consistent and overlapping pattern of brain activity. The overlap was most pronounced for the bilateral parietal cortex , and dorsolateral prefrontal cortex . The common fronto-parietal activity will be discussed in terms of processes related to integration of distributed representations in the brain. (shrink)

One important distinction in psychology is between inferences based on associative memory and inferences based on analysis and rules. Much previous empirical work conceive of associative and analytical processes as two exclusive ways of addressing a judgment task, where only one process is selected and engaged at a time, in an either-or fashion. However, related work indicate that the processes are better understood as being in interplay and simultaneously engaged. Based on computational modeling and brain imaging of spontaneously adopted judgment (...) strategies together with analyses of brain activity elicited in tasks where participants were explicitly instructed to perform similarity-based associative judgments or rule-based judgments (n = 74), we identified brain regions related to the two types of processes. We observed considerable overlap in activity patterns. The precuneus was activated for both types of judgments, and its activity predicted how well a similarity-based model fit the judgments. Activity in the superior frontal gyrus predicted the fit of a rule-based judgment model. The results suggest the precuneus as a key node for similarity-based judgments, engaged both when overt responses are guided by similarity-based and rule-based processes. These results are interpreted such that similarity-based processes are engaged in parallel to rule-based-processes, a finding with direct implications for cognitive theories of judgment. (shrink)

To investigate the possible dichotomy between the neurophysiological bases of perceptual transitions versus sustaining a particular percept over time, an fMRI study was conducted with subjects viewing fragmented pictures. Unlike most other perceptually unstable stimuli, fragmented pictures give rise to only one perceptual transition and a continuous period of sustained perception. Earlier research is inconclusive on the subject of which anatomical regions should be attributed to what temporal aspect of perception, and the aim of the present study was to shed (...) more light on the subject. In this study occipitotemporal and fronto-parietal regions were found to be activated for both aspects. However, regions in the medial-temporal lobe were activated specifically for transitions, whereas medial and dorsolateral prefrontal regions were activated specifically for sustained perception. These results provide further support for the theory that the initial creation of perceptual awareness and upholding perceptual awareness over time are separate processes involving different brain regions. (shrink)

A large body of evidence supports the idea that a common fronto-parietal network is activated across a range of diverse cognitive functions. Jung & Haier's (J&H's) review demonstrates a very similar pattern of activity, which correlates with individual differences in intelligence. We propose that these converging lines of evidence are best interpreted as a general role of the fronto-parietal network in integration and control.

A common way of analyzing the statistical relation between two tests of memory is to use contingency analyses. A potential problem with such analyses is known as Simpson’s paradox. The paradox is that collapsing two or more contingency tables may have the effect that the relationship expressed in the overall contingency table differs from the relationships expressed in the original tables. The paradox arises when covariates are correlated with each of the tests. It has been claimed that the paradox has (...) implications for the analysis of memory retrieval, and ways of solving the problem have been called for (Hintzman, 1980). In this paper, partial gamma (Davis, 1967) is suggested as one possible solution. This method can be used to compute a weighted average of the results in the original tables. The use of partial gamma is exemplified by applying it to hypothetical instances of Simpson’s paradox. (shrink)

The brain networks underlying human multiple-cue judgment, the judgment of a continuous criterion based on multiple cues, have been examined in a few recent studies, and the ventral precuneus has been found to be a key region. Specifically, activation differences in ventral precuneus (as measured with functional magnetic resonance imaging, fMRI) has been linked to an exemplar-based judgment process, where judgments are based on memory for previous similar cases. What aspects of exemplar-based judgment ventral precuneus supports is however poorly understood. (...) Ventral precuneus is a brain region important for various episodic memory processes, where increased engagement of this region together with the ventromedial prefrontal cortex (vmPFC) and the medial temporal lobes (MTL) during learning have been linked to retrieval success. Several alternatives are plausible, for example that reduced brain activity in ventral precuneus during learning to make exemplar-based judgments could reflect reduced needs for visuo-spatial attention as a function of learning to master the task. The present study used fMRI during a multiple-cue judgment task to gain novel neurocognitive evidence informative for the link between learning-related activity changes in ventral precuneus and exemplar-based judgment. Participants (N = 27) spontaneously learned to make judgments during fMRI, in a multiple-cue judgment task specifically designed to induce exemplar-based processing. Contrasting brain activity during late learning to early learning indeed revealed higher activity in ventral precuneus, the bilateral MTL and the vmPFC. Activity in the ventral precuneus and the vmPFC was found to parametrically increase between each judgment event, and activity levels in the ventral precuneus predicted performance after learning. These results are interpreted such that the ventral precuneus supports the aspects of exemplar-based processes that are related to episodic memory, tentatively by building and retrieving memory representations for judgment. (shrink)

There is an emerging consensus that retrieval practice is a powerful way to enhance long-term retention and to reduce achievement gaps in school settings. Less is known whether retrieval practice benefits performance in individuals with low intrinsic motivation to spend time and effort on a given task, as measured by self-reported need for cognition. Here, we examined retrieval practice in relation to individual differences in NFC by combining behavioral and functional magnetic resonance imaging data. Using a within-subject design, upper-secondary school (...) students learned a language-based material, with half of the items by means of retrieval practice with feedback and half by study only. One week later, the students were tested on the word-pairs either in the classroom, or in a fMRI scanner. In both settings, a retrieval practice effect was observed across different levels of NFC. Relatedly, comparable fMRI effects were seen in both NFC subgroups. Taken together, our findings provide behavioral and brain-imaging evidence that retrieval practice is effective also for individuals with lower levels of NFC, which is of direct relevance for educational practice. (shrink)