Neuronal effects following working memory training

AbstractThere is accumulating evidence that training working memory (WM) leads to beneficial effects in tasks that were not trained, but the mechanisms underlying this transfer remain elusive. Brain imaging can be a valuable method to gain insights into such mechanisms. Here, we discuss the impact of cognitive training on neural correlates with an emphasis on studies that implemented a WM intervention. We focus on changes in activation patterns, changes in resting state connectivity, changes in brain structure, and changes in the dopaminergic system. Our analysis of the existing literature reveals that there is currently no clear pattern of results that would single out a specific neural mechanism underlying training and transfer. We conclude that although brain imaging has provided us with information about the mechanisms of WM training, more research is needed to understand its neural impact

Do Social Network Sites Enhance or Undermine Subjective Well‐Being? A Critical Review

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136039/1/sipr12033.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136039/2/sipr12033_am.pd

Third-person self-talk facilitates emotion regulation without engaging cognitive control: Converging evidence from ERP and fMRI.

Does silently talking to yourself in the third-person constitute a relatively effortless form of self control? We hypothesized that it does under the premise that third-person self-talk leads people to think about the self similar to how they think about others, which provides them with the psychological distance needed to facilitate self control. We tested this prediction by asking participants to reflect on feelings elicited by viewing aversive images (Study 1) and recalling negative autobiographical memories (Study 2) using either I or their name while measuring neural activity via ERPs (Study 1) and fMRI (Study 2). Study 1 demonstrated that third-person self-talk reduced an ERP marker of self-referential emotional reactivity (i.e., late positive potential) within the first second of viewing aversive images without enhancing an ERP marker of cognitive control (i.e., stimulus preceding negativity). Conceptually replicating these results, Study 2 demonstrated that third-person self-talk was linked with reduced levels of activation in an a priori defined fMRI marker of self-referential processing (i.e., medial prefrontal cortex) when participants reflected on negative memories without eliciting increased levels of activity in a priori defined fMRI markers of cognitive control. Together, these results suggest that third-person self-talk may constitute a relatively effortless form of self-control

Assessing automaticity

We propose two principles that should be followed in the study of automaticity for cognitive processes. Both follow from the general rule that experimental research should be guided by a model of the task in question, frequently a process model. The first is that the concept of automaticity is best applied to component processes of complex behaviors rather than to behaviors as a whole. The second is that the criteria chosen for the identification of automaticity should be motivated by the processes in question. Examples are discussed of research programs that are relevant to each principle.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25469/1/0000009.pd

Cognitive load and maintenance rehearsal

In recent years there has been a good deal of debate about the role of rote, repetitive rehearsal (called Type I or maintenance rehearsal) on the establishment of memory traces that outlast the rehearsal process itself. One advance in the technology used to study this problem is the operational definition of maintenance rehearsal proposed by Glenberg and Adams (1978, Journal of Verbal Learning and Verbal Behavior, 17, 455-463). These authors argued that maintenance rehearsal should be defined as the continuous maintenance of information in memory using minimal cognitive capacity. Here this definition was adopted and extended in a paradigm in which the mental resources devoted to maintenance rehearsal could be systematically varied. The experiment revealed that there is, indeed, an effect of maintenance rehearsal on long-term recognition performance and that this effect depends on the mental resources devoted to the rehearsal process.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24749/1/0000171.pd

Age Differences in Behavior and PET Activation Reveal Differences in Interference Resolution in Verbal Working Memory

Older adults were tested on a verbal working memory task that used the item-recognition paradigm. On some trials of this task, response-conflict was created by presenting test-items that were familiar but were not members of a current set of items stored in memory. These items required a negative response, but their familiarity biased subjects toward a positive response. Younger subjects show an interference effect on such trials, and this interference is accompanied by activation of a region of left lateral prefrontal cortex. However, there has been no evidence that the activation in this region is causally related to the interference that the subjects exhibit. In the present study, we demonstrate that older adults show more behavioral interference than younger subjects on this task, and they also show no reliable activation at the same lateral prefrontal site. This leads to the conclusion that this prefrontal site is functionally involved in mediating resolution among conflicting responses or among conflicting representations in working memory

Recognition of the stimulus suffix

Recall of the final items in a spoken list is hindered by the presentation of a to-be-ignored item. The magnitude of this interference (the stimulus suffix effect) is reduced if the suffix is perceptually distinct from the other list items. Several experiments examine this effect of perceptual distinctiveness. The experiments involve later recognition of stimulus suffixes from lists presented for serial recall. Suffixes which differ from the list items tend to be recognized at least as well as list-similar suffixes. This supports the view that reduction of the suffix effect can be traced to decreased interitem interference in memory rather than to attentional selection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26029/1/0000102.pd

Inhibitory Selection Mechanisms in Clinically Healthy Older and Younger Adults

OBJECTIVE: Declines in working memory are a ubiquitous finding within the cognitive-aging literature. A unitary inhibitory selection mechanism that serves to guide attention toward task-relevant information and resolve interference from task-irrelevant information has been proposed to underlie such deficits. However, inhibition can occur at multiple time points in the memory-processing stream. Here, we tested whether the time point at which inhibition occurs in the memory-processing stream affects age-related memory decline. METHOD: Clinically healthy younger (n = 23) and older (n = 22) adults performed two similar item-recognition working memory tasks. In one task, participants received an instruction cue telling them which words to attend to followed by a memory set, promoting perceptual inhibition at the time of encoding. In the other task, participants received the instruction cue after they received the memory set, fostering inhibition of items already in memory. RESULTS: We found that older and younger adults differed in their ability to inhibit items both during encoding and when items had to be inhibited in memory but that these age differences were exaggerated when irrelevant information had to be inhibited from memory. These results provide insights into the mechanisms that support cognitive changes to memory processes in healthy aging

Memory for affectively valenced and neutral stimuli in depression: evidence from a novel matching task

Depressed persons have better memory for affectively negative than positive stimuli, a pattern generally not exhibited by non-depressed individuals. The mechanisms underlying this differential memory are not clear. In this study we examined memory for valenced and neutral stimuli in depressed and non-depressed individuals under conditions of relatively unconstrained encoding. AQ1 We developed a novel task based on the game, Concentration, in which participants tried to match pairs of positive and negative words, and pairs of neutral words, hidden under squares in as few turns as possible. Whereas non-depressed participants selected and turned over positive squares more frequently than they did negative squares, depressed participants selected and turned over positive and negative squares equally often. Depressed participants also matched fewer positive word pairs within the first five minutes of the task than did non-depressed participants, and they exhibited poorer learning of positive words. Depressed and non-depressed participants did not differ in their matching of neutral words. AQ2 These findings add to a growing literature indicating that depression is characterised by difficulties in the processing of positive stimuli