scholarly journals Rhythmic Accessibility to Sequential Working Memory in a Theta Phase-Dependent Manner

2021 ◽  
Author(s):  
Takuya Ideriha ◽  
Junichi Ushiyama

Working memory is active short-term memory storage that is easily accessible and underlies various activities, such as maintaining phone numbers in mind for a short period [1,2]. There is accumulating theoretical and physiological evidence that memorized items are represented rhythmically by neural oscillation in the theta range (4-7 Hz) [3,4]. However, the impact of this process on human behavior is yet to be examined. Here we show that simply memorizing sequential information affects a behavioral index (i.e., reaction time, RT) in a rhythmic manner. In the main experiment (Experiment 1), we measured RTs to a visual probe that appeared at one of two sequentially memorized locations after a random interval. Consequently, RTs to the first and second probes each fluctuated in the theta range as a function of the random interval, and the phases of the two theta fluctuations were not in phase or anti-phase, but shifted by approximately 270 degree. Interestingly, the 270 degree phase difference corresponded to the rhythm of "phase coding", where sequential information is represented on the specific phase of theta oscillation [5-7]. These relationships were not observed in tasks simply requiring attention (Experiment 2) or memorization (Experiment 3) of spatial locations without sequential order. In conclusion, the current results demonstrate that our behavior fluctuates when recalling memorized sequential items in the theta-range, suggesting that accessibility to sequential working memory is rhythmic rather than stable, possibly reflecting theta-phase coding.

2020 ◽  
Author(s):  
Xueying Fu ◽  
Chaoxiong Ye ◽  
huzhonghua ◽  
Tengfei Liang ◽  
Ziyuan Li ◽  
...  

Memory performance can be improved by retrospectively cueing an item maintained in visual working memory (VWM). Different hypotheses have been proposed to explain the mechanisms behind retro-cueing and VWM. Previous behavioral studies suggest that different retro-cue validities may lead individuals to implement retro-cues in different ways to obtain a retro-cue effect. However, there is still no clear electroencephalogram (EEG) evidence to support that the retro-cue effect under different validity conditions is triggered by different mechanisms. Herein, we investigated whether retro-cue validity modulated the mechanisms underlying the retro-cue effect in VWM by using EEGs. We manipulated retro-cue validity by using blocks in a color change detection task. Contralateral delay activity (CDA) and lateralized alpha power were used assess spatial attention and memory storage, respectively. Significant retro-cue effects were observed under both high- and low-validity conditions. More importantly, although the retro-cue could redirect spatial attention under both high- and low-validity conditions, we found that participants maintained the non-cued items during a measured time interval under the low-validity condition, but dropped them out of VWM under the high-validity condition. Our results resolve previous contradictory findings. The retro-cue effect in our study can be explained by the removal hypothesis, prioritization hypothesis, and protection-during-retrieval hypothesis. This work suggests that the mechanisms underlying the retro-cue effect are not mutually exclusive, but determined by the cue validity. Individuals can voluntarily choose different mechanisms based on the expected retro-cue validity.


2019 ◽  
Author(s):  
Karen M. Rodrigue ◽  
Ana M. Daugherty ◽  
Chris M. Foster ◽  
Kristen M. Kennedy

AbstractNon-heme iron accumulation contributes to age-related decline in brain structure and cognition via a cascade of oxidative stress and inflammation, although its effect on brain function is largely unexplored. Thus, we examine the impact of striatal iron on dynamic range of BOLD modulation to working memory load. N=166 healthy adults (age 20-94) underwent cognitive testing and an imaging session including n-back (0-, 2-, 3-, and 4-back fMRI), R2*-weighted imaging, and pcASL to measure cerebral blood flow. A statistical model was constructed to predict voxelwise BOLD modulation by age, striatal iron content and an age × iron interaction, controlling for cerebral blood flow, sex, and task response time. A significant interaction between age and striatal iron content on BOLD modulation was found selectively in the putamen, caudate, and inferior frontal gyrus. Greater iron was associated with reduced modulation to difficulty, particularly in middle-aged and younger adults with greater iron content. Further, iron-related decreases in modulation were associated with poorer executive function in an age-dependent manner. These results suggest that iron may contribute to differences in functional brain activation prior to older adulthood, highlighting the potential role of iron as an early factor contributing to trajectories of functional brain aging.


2016 ◽  
Vol 26 (1) ◽  
pp. 125-136 ◽  
Author(s):  
Susan Colmar ◽  
Nash Davis ◽  
Linda Sheldon

An exploratory applied study, using a set of attention and working memory strategies specifically developed for students and named Memory Mates, was completed with normally developing students attending a primary school. Students in one classroom received the intervention, while the other classroom functioned as a control group. The study was experimental, with quantitative measures. Additional qualitative data was collected to facilitate the ongoing development of Memory Mates. A working memory instrument was used to rank students initially, and as a post-intervention measure for children with low working memory, with some gains in working memory observed in the experimental classroom students. Data were collected on academic achievement in reading, spelling, and maths. Post-intervention data analysis of the impact of the Memory Mates intervention showed no differences between the experimental and control groups for standardised academic measures. Several reasons are postulated for the lack of significant quantifiable change, chiefly the short period of intervention.


2020 ◽  
Vol 63 (9) ◽  
pp. 3036-3050
Author(s):  
Elma Blom ◽  
Tessel Boerma

Purpose Many children with developmental language disorder (DLD) have weaknesses in executive functioning (EF), specifically in tasks testing interference control and working memory. It is unknown how EF develops in children with DLD, if EF abilities are related to DLD severity and persistence, and if EF weaknesses expand to selective attention. This study aimed to address these gaps. Method Data from 78 children with DLD and 39 typically developing (TD) children were collected at three times with 1-year intervals. At Time 1, the children were 5 or 6 years old. Flanker, Dot Matrix, and Sky Search tasks tested interference control, visuospatial working memory, and selective attention, respectively. DLD severity was based on children's language ability. DLD persistence was based on stability of the DLD diagnosis. Results Performance on all tasks improved in both groups. TD children outperformed children with DLD on interference control. No differences were found for visuospatial working memory and selective attention. An interference control gap between the DLD and TD groups emerged between Time 1 and Time 2. Severity and persistence of DLD were related to interference control and working memory; the impact on working memory was stronger. Selective attention was unrelated to DLD severity and persistence. Conclusions Age and DLD severity and persistence determine whether or not children with DLD show EF weaknesses. Interference control is most clearly impaired in children with DLD who are 6 years and older. Visuospatial working memory is impaired in children with severe and persistent DLD. Selective attention is spared.


2019 ◽  
Author(s):  
Ashley DiPuma ◽  
Kelly Rivera ◽  
Edward Ester

Working memory (WM) performance can be improved by an informative cue presented during storage. This effect, termed a retro-cue benefit, can be used to explore mechanisms of attentional prioritization in WM. Directing attention to a single item stored in memory is known to increase memory precision while decreasing the likelihood of incorrect item reports and random guesses, but it is unclear whether similar benefits manifest when participants direct attention to multiple items stored in memory. We tested this possibility by quantifying memory performance when participants were cued to prioritize one or two items stored in working memory. Consistent with prior work, cueing participants to prioritize a single memory item yielded higher recall precision, fewer swap errors, and fewer guesses relative to a neutral cue condition. Conversely, cueing participants to prioritize two memory items yielded fewer swap errors relative to a neutral condition, but no differences in recall precision or guess rates. Although swap rates were less likely during the cue-two vs. neutral conditions, planned comparisons revealed that when participants made swap errors during cue-two trials they were far more likely to confuse two prioritized stimuli than they were to confuse a prioritized stimulus vs. a non-prioritized stimulus. Our results suggest that it is possible to prioritize multiple items stored in memory, with the caveat that doing so may increase the probability of confusing prioritized items.


Author(s):  
Ilma Robo

The treatment of periodontal diseases, mainly of their origin, with the most common clinical manifestation in form of gingival inflammation, is manifold and powerful, including: mechanical therapy, antibiotic, antiseptic and various approaches to treatment, which are recommended to be used within a short period of time. New therapeutic approaches have been proven as alternative treatment to conventional therapy, or in combination with conventional therapies, to reduce the number of periodontopathic pathogens in gingival sulcus. HBOT has a detrimental effect on periodontal microorganisms, as well as beneficial effects on the healing of periodontal tissue, increasing oxygen pressure in gingival pockets. Our study is aimed at reviewing the current published literature on hyperbaric oxygen therapy and focuses on role of HBOT as a therapeutic measure for the individual with periodontal disease in general and for the impact on the recovery of gingival inflammation. HBOT and periodontal treatment together, reduce up to 99% of the gram-negative anaerobic load of subgingival flora. HBOT, significantly reduces subgingival anaerobic flora. Clinical effects in 2-year follow-up of treated patients are sensitive. Reduction of gingival hemorrhage indexes, depth of peritoneum, plaque index, occurs in cases of combination of HBOT and detraction. Reduced load persists up to 2 months after therapy. The significant increase in connective tissue removal starts at the end of 2nd week, to achieve the maximum in week 3-6 of application. HBOT used for re-implantation, stimulates the healing of periodontal membrane, pulp, prevents root resorption, healing of periodontal lining tissues. HBOT, significantly reduces the hemorrhage index with 1.2 value difference, 0.7mm probe depth, reduces gingival fluid by 2. HGH exposure is increased by gingival blood flow, with a difference of 2 in measured value. The therapeutic effects of HBOT in the value of the evaluation index can be saved up to 1-year post treatment.


2018 ◽  
Vol 18 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Aikebaier Maimaiti ◽  
Amier Aili ◽  
Hureshitanmu Kuerban ◽  
Xuejun Li

Aims: Gallic acid (GA) is generally distributed in a variety of plants and foods, and possesses cell growth-inhibiting activities in cancer cell lines. In the present study, the impact of GA on cell viability, apoptosis induction and possible molecular mechanisms in cultured A549 lung carcinoma cells was investigated. Methods: In vitro experiments showed that treating A549 cells with various concentrations of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA inhibits cell viability, comparative proteomic analysis was applied. The changed proteins were identified by Western blot and siRNA methods. Results: Two-dimensional electrophoresis revealed changes that occurred to the cells when treated with or without GA. Four up-regulated protein spots were clearly identified as malate dehydrogenase (MDH), voltagedependent, anion-selective channel protein 1(VDAC1), calreticulin (CRT) and brain acid soluble protein 1(BASP1). VDAC1 in A549 cells was reconfirmed by western blot. Transfection with VDAC1 siRNA significantly increased cell viability after the treatment of GA. Further investigation showed that GA down regulated PI3K/Akt signaling pathways. These data strongly suggest that up-regulation of VDAC1 by GA may play an important role in GA-induced, inhibitory effects on A549 cell viability.


Author(s):  
Matthew L. Hall

Deaf and hard of hearing (DHH) children have been claimed to lag behind their hearing peers in various domains of cognitive development, especially in implicit learning, executive function, and working memory. Two major accounts of these deficits have been proposed: one based on a lack of auditory access, and one based on a lack of language access. This chapter reviews these theories in relation to the available evidence and concludes that there is little evidence of direct effects of diminished auditory access on cognitive development that could not also be explained by diminished language access. Specifically, reports of deficits in implicit learning are not broadly replicable. Some differences in executive function do stem from deafness itself but are not necessarily deficits. Where clinically relevant deficits in executive function are observed, they are inconsistent with the predictions of accounts based on auditory access, but consistent with accounts based on language access. Deaf–hearing differences on verbal working memory tasks may indicate problems with perception and/or language, rather than with working memory. Deaf–hearing differences on nonverbal tasks are more consistent with accounts based on language access, but much more study is needed in this area. The chapter concludes by considering the implications of these findings for psychological theory and for clinical/educational practice and by identifying high-priority targets for future research.


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