Browsing by Subject "Working memory"

Now showing 1 - 7 of 7

Open Access
Analysis of differentially expressed genes in bipolar disorder: transcriptomic signature of adolescence and young adulthood in working memory-relared area
(2020-11) Şen, Rabia
Bipolar disorder (BD) is a heritable severe illness. One of the indications of BD is working memory (WM) impairment which is a heritable cognitive trait. The aim of the current study is to identify the transcriptomic level developmental biomarkers of BD in WM-related brain regions. We based our analysis on adolescence and young adulthood (AYA), the critical period for both BD and cognitive development. We have chosen 4 publicly available microarray datasets from Gene Omnibus database for which one is derived from healthy controls and three from bipolar disorder patients. We compared different developmental periods of the brains of normal subjects to determine healthy brain development at the transcriptomic level. After applying the same method to detect bipolar development to show differences between BD and healthy brains. We followed these comparisons in two steps; on gene-level analysis and geneset level analysis. Next, we identified common genes and pathways from the results of different analyses. As a result of this comparison, while six genes were identified differentially expressed, we observed 5 Gene Ontology (GO) genesets shown different regulation patterns in bipolar and healthy brains. The literature review has been shown that the significant biological pathways might be influenced by the treatment.
Open Access
Associations between psychosis endophenotypes across brain functional, structural, and cognitive domains
(Cambridge University Press, 2018) Blakey, R.; Ranlund, S.; Zartaloudi, E.; Cahn, W.; Calafato, S.; Colizzi, M.; Crespo-Facorro, B.; Daniel, C.; Díez-Revuelta, A.; Forti, M. D.; Iyegbe, C.; Jablensky, A.; Jones, R.; Hall, M. -H.; Kahn, R.; Kalaydjieva, L.; Kravariti, E.; Lin, K.; McDonald, C.; McIntosh, A. M.; Picchioni, M.; Powell, J.; Presman, A.; Rujescu, D.; Schulze, K.; Shaikh, M.; Thygesen, J. H.; Toulopoulou, Timothea; Haren, N. V.; Os, J. V.; Walshe, M.; Murray, R. M.; Bramon, E.
Background A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.Methods This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.Results The P300 amplitude and latency were not associated (regression coef.-0.06, 95% CI-0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10-0.28, p < 0.001). There was no evidence of associations between lateral ventricular volume and the other measures (all p > 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.Conclusions The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.
Open Access
Effect of Covid-19 infection on the developing brain: psychosis proneness and working memory activation
(2022-08) Sozan, Sara Sinem
Researchers have been investigating the effects of Covid-19 infection since late 2019. Symptoms caused by the SARS-Cov-2 virus varied from respiratory system failure to fatigue, brain fog and headaches. Studies showed that the infection leads to cognitive impairment and psychotic-like symptoms even after recovery. Literature has focused on hospitalized adult patients, and there is less information on how the developing brain exposed to the virus is affected. To address these gaps in the literature we investigated whether Covid-19 can be a risk factor for psychosis in adolescents and young adults. Forty individuals who were infected with Covid-19 and recovered at least two and at most four months before and 36 demographically matched controls were recruited in the study. Positive PCR test results confirmed the infection status of the participants. Subclinical psychosis was assessed using the Community Assessment of Psychic Experience (CAPE-42) questionnaire and the Structured Interview of Schizotypy - Revised (SIS-R) was used to assess psychotic-like symptoms. A functional magnetic resonance imaging was conducted during a well-known working memory task to investigate activation patterns. The working memory task involved seven tasks and a control motor task. Verbal fluency performance was assessed in both phonetic and semantic categories. In order to control for the confounding effects of additional environmental risk factors for psychosis, paternal age, years of urban upbringing, cannabis exposure, and ethnicity were also considered. The findings revealed that although the two groups did not differ across different dimensions of the CAPE-42, the infected group had higher restricted affect and referential thoughts of being watched. Individuals infected with SARS-Cov-2 performed worse in both categories of the verbal fluency task. fMRI analysis revealed that individuals infected with the SARS-Cov-2 virus showed activation differences in the prefrontal cortex, medial temporal gyrus, middle frontal gyrus, and inferior parietal gyrus. Higher performance in the verbal fluency task predicted greater activation during the working memory task. These results suggest that exposure to the Covid-19 infection during brain development can be an environmental risk factor for psychosis.
Open Access
Investigation of how task related programs affect activation of frontoparietal regions
(2023-01) Çiftçi, İpek
We prepare breakfast, take a shower, do grocery shopping. While completing these daily goals we don’t individually execute many components. For instance, while preparing instant coffee we sequentially execute subtask such as ’take the coffee, boil water, put coffee and water to a mug, take a spoon, mix it with spoon’ under the goal of preparing the coffee but we don’t individually execute them. We execute this whole temporally extended task as one entity which is called ’preparing instant coffee’ in this example. We execute a temporally extended, goal-directed behavior as one entity. The construction of this extended behavior in cognition is hierarchical since it consists of subtasks that complete the subgoals in different levels. For example, the step ’put coffee and water to a mug’ completes the subgoal of putting necessary ingredients together. Mixing them completes the actual goal. In terms of goal completion, former one is in a lower level than latter one. Execution of extended behavior that subsumes the entire task occurs via programs. Programs are related to the entire task. These programs are constructed in the beginning of episode. A program of a longer task requires larger programs than same but shorter task. Executing a longer task as one entity is more demanding than a shorter task. So, the program load of the longer task higher than the shorter one. it has been shown that the reaction time of the first item in a longer task is greater than the same but a shorter task [1]. A set of fronto-parietal regions (also known as Multiple Demands (MD) regions) activates in response to goal-directed tasks that require cognitive control and attention. Activation in MD regions higher for more demanding tasks. Demanding task here can be the tasks that have more working memory load or requires more cognitive control demands. In other words, a higher cognitive load is associated with higher activity in MD regions. Can it be a different cognitive load processing differently than the defined above? If the program loads differently than the typical cognitive load defined in the literature, the activity pattern in MD regions should be different than the typical effect of cognitive load in MD regions. In this study, we investigated this issue. In the experiment, participants executed 3-back task in 2 conditions. One condition had high working memory load (high cognitive control demands) and high program load. The other condition had low working memory load (low cognitive control demands) and low program load. Results showed that activity in low working memory load conditions in MD regions was higher than the activity in high working memory load condition. This indicates that the program load has different construction from working memory load because, it reflects different pattern of activity in MD regions.
Open Access
Working memory capacity: concurrent subtasks need not interfere
(2022-10) Şengil, Gülsüm Özge
Any extended task episode is subsumed by goal-directed programs that hierar- chically control its execution. We investigated the relationship between working memory capacity and the control instantiated by such hierarchical task entities across four experiments. In a new extended task consisting of subtask A and subtask B, participants first memorized the orientation of subtask A lines (let’s call this event mA), then memorized subtask B lines (mB), then recalled these B lines (rB), and finally recalled A lines (rA). The task structure was: mA-mB-rB- rA. Subtask A lines were thus held in mind during the execution of subtask B. Even though participants had to remember the orientation of lines in both cases, increased WM load of lines A only affected performance on subtask A and did not affect the performance on subtask B. In Experiment 2, four trials of Exp1 were organized into a complex 4-part task with the added condition that A lines of a part be recalled not in that part but in the next part. The task structure was: mA1-mB1-rB1—mA2-mB2-rB2-rA1—mA3-mB3-rB3-rA2—mB3-rB3-rA3. Load of A lines again did not affect B lines. Crucially, load of A2 and A3 lines did not affect the recall of A1 and A2 lines, respectively. In Experiment 3, in a design similar to Exp1, time constraint on mA and mB increased the interference across concurrent subtasks. Experiment 4 showed that increasing the similarity between subtask A and subtask B of Exp1 may increase the across-subtask in terference. We show that WM information of different concurrent subtasks can be maintained separately, perhaps as part of their goal-directed programs. And, encoding to these non-interfering stores, as well as retrieval from them, might depend on attentional and time-based mechanisms.
Open Access
Working memory circuit as a function of increasing age in healthy adolescence: a systematic review and meta-analyses
(Elsevier Ltd, 2016-02) Andrea, J.; Picchionib, M.; Zhang, R.; Toulopoulou, T.
Working memoryability maturesthroughpubertyand early adulthood. Deficits inworkingmemoryare linkedtothe risk of onset of neurodevelopmental disorders such as schizophrenia, and there is a significant temporal over-lap between the peak offirst episodepsychosisrisk and working memorymaturation. Inorder to characterize thenormal working memory functional maturation process through this critical phase of cognitive development weconducted a systematic review and coordinate based meta-analyses of all the available primary functional mag-netic resonance imaging studies (n = 382) that mapped WM function in healthy adolescents (10–17 years) andyoung adults (18–30 years). Activation Likelihood Estimation analyses across all WMtasks revealed increased ac-tivation with increasing subject age in the middle frontal gyrus (BA6) bilaterally, the left middle frontal gyrus(BA10), the left precuneus and left inferior parietal gyri (BA7; 40). Decreased activation with increasing agewas found in the right superior frontal (BA8), left junction of postcentral and inferior parietal (BA3/40), andleft limbic cingulate gyrus (BA31). These results suggest that brain activation during adolescence increasedwith age principally in higher order cortices, part of the core working memory network, while reductions weredetected in more diffuse and potentially more immature neural networks. Understanding the process bywhich the brain and its cognitive functions mature through healthy adulthood may provide us with new cluesto understanding the vulnerability to neurodevelopmental disorders.
Open Access
Working memory related to different subtasks can be maintained in separate, non-interfering stores
(2024-07) Rezaei, Aida
How can WM maintain more information when its capacity is only around 4 items? Here, we explore the possibility that information related to separate subtasks do not count towards this limit, perhaps, because they are maintained in non-interfering stores. Across the two experiments, we investigated if increasing the WM load related to one subtask interfered with the execution of a concurrent but distinct second subtask. In Experiment 1, participants first saw pictures that were to be kept in mind and used for a later subtask B. They then executed subtask A, while keeping in mind these subtask B pictures. Although subtasks A and B involved maintaining and updating identical sets of pictures, increasing the number of subtask B pictures did not interfere with subtask A execution, which was only affected when the number of pictures relevant to it was increased, suggesting that subtask A and B pictures were maintained in separate non-interfering stores. An objection might be that in Experiment 1, subtask B pictures were passively and not goal-directedly maintained. In Experiment 2, participants executed a more complex subtask that forced participants to maintain and update two separate sets of subtask B pictures while executing subtask A and subtask A also involved WM maintenance and updating of identical pictures. We found that even here increased load of subtask B pictures did not affect subtask A performance. Thus, at least in some multitasking situations, information related to distinct subtasks can be maintained in separate non-interfering stores.