Expectations impact short-term memory through changes in connectivity between attention- and task-related brain regions

Cortex ◽  
2016 ◽  
Vol 78 ◽  
pp. 1-14 ◽  
Author(s):  
Christopher Sinke ◽  
Katarina Forkmann ◽  
Katharina Schmidt ◽  
Katja Wiech ◽  
Ulrike Bingel
Keyword(s):  
Short Term Memory ◽  
Brain Regions ◽  
Short Term ◽  
Term Memory ◽  
And Task

scholarly journals Quantifying differences between passive and task-evoked intrinsic functional connectivity in a large-scale brain simulation

2018 ◽  
Author(s):  
Antonio Ulloa ◽  
Barry Horwitz
Keyword(s):  
Computational Model ◽  
Resting State ◽  
Short Term Memory ◽  
Brain Activity ◽  
Brain Regions ◽  
Intrinsic Activity ◽  
Task Execution ◽  
Short Term ◽  
Visual Short Term Memory ◽  
And Task

AbstractEstablishing a connection between intrinsic and task-evoked brain activity is critical because it would provide a way to map task-related brain regions in patients unable to comply with such tasks. A crucial question within this realm is to what extent the execution of a cognitive task affects the intrinsic activity of brain regions not involved in the task. Computational models can be useful to answer this question because they allow us to distinguish task from non-task neural elements while giving us the effects of task execution on non-task regions of interest at the neuroimaging level. The quantification of those effects in a computational model would represent a step towards elucidating the intrinsic versus task-evoked connection. Here we used computational modeling and graph theoretical metrics to quantify changes in intrinsic functional brain connectivity due to task execution. We used our Large-Scale Neural Modeling framework to embed a computational model of visual short-term memory into an empirically derived connectome. We simulated a neuroimaging study consisting of ten subjects performing passive fixation (PF), passive viewing (PV) and delay match-to-sample (DMS) tasks. We used the simulated BOLD fMRI time-series to calculate functional connectivity (FC) matrices and used those matrices to compute several graph theoretical measures. After determining that the simulated graph theoretical measures were largely consistent with experiments, we were able to quantify the differences between the graph metrics of the PF condition and those of the PV and DMS conditions. Thus, we show that we can use graph theoretical methods applied to simulated brain networks to aid in the quantification of changes in intrinsic brain functional connectivity during task execution. Our results represent a step towards establishing a connection between intrinsic and task-related brain activity.Author SummaryStudies of resting-state conditions are popular in neuroimaging. Participants in resting-state studies are instructed to fixate on a neutral image or to close their eyes. This type of study has advantages over traditional task-based studies, including its ability to allow participation of those with difficulties performing tasks. Further, a resting-state neuroimaging study reveals intrinsic activity of participants’ brains. However, task-related brain activity may change this intrinsic activity, much as a stone thrown in a lake causes ripples on the water’s surface. Can we measure those activity changes? To answer that question, we merged a computational model of visual short-term memory (task regions) with an anatomical model incorporating major connections between brain regions (non-task regions). In a computational model, unlike real data, we know how different regions are connected and which regions are doing the task. First, we simulated neuronal and neuroimaging activity of both task and non-task regions during three conditions: passive fixation (baseline), passive viewing, and visual short-term memory. Then, applying graph theory to the simulated neuroimaging of non-task regions, we computed differences between the baseline and the other conditions. Our results show that we can measure changes in non-task regions due to brain activity changes in task-related regions.

Hierarchical Menu Design: Breadth, Depth, and Task Complexity

1996 ◽  
Vol 82 (3_suppl) ◽  
pp. 1187-1201 ◽  
Author(s):  
Julie A. Jacko ◽  
Gavriel Salvendy
Keyword(s):  
Short Term Memory ◽  
Memory Load ◽  
Task Complexity ◽  
Short Term ◽  
Term Memory ◽  
Independent Variables ◽  
Cognitive Component ◽  
Dependent Variables ◽  
Perceived Complexity ◽  
And Task

In this research a relationship between an hierarchical menu's depth and the perceived complexity of a task involving menu retrieval was proposed and validated. 12 subjects were asked to use six different hierarchical menus of varying breadth and depth. The dependent variables were response time and accuracy. The independent variables were depth and breadth of the hierarchy. Subsequent to experimentation, the subjects were asked to complete a questionnaire on users' perceptions of the complexity of the different menu structures. As depth increased, perceived complexity of the menus increased significantly. These phenomena are linked to an existing theory of task complexity. We suggest that the cognitive component influencing users' perceptions of task complexity was short-term memory load.

scholarly journals A shared representation of order between encoding and recognition in visual short-term memory

2016 ◽  
Author(s):  
Kristjan Kalm ◽  
Dennis Norris
Keyword(s):  
Short Term Memory ◽  
Activity Patterns ◽  
Positional Information ◽  
Brain Regions ◽  
Order Information ◽  
Short Term ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Recognition Phase ◽  
The Individual

AbstractMost complex tasks require people to bind individual stimuli into a sequence in short term memory (STM). For this purpose information about the order of the individual stimuli in the sequence needs to be in active and accessible form in STM over a period of few seconds. Here we investigated how the temporal order information is shared between the presentation and response phases of an STM task. We trained a classification algorithm on the fMRI activity patterns from the presentation phase of the STM task to predict the order of the items during the subsequent recognition phase. While voxels in a number of brain regions represented positional information during either presentation and recognition phases, only voxels in the lateral prefrontal cortex (PFC) and the anterior temporal lobe (ATL) represented position consistently across task phases. A shared positional code in the ATL might reflect verbal recoding of visual sequences to facilitate the maintenance of order information over several seconds.

scholarly journals Does sustained ERP activity in posterior lexico-semantic processing areas during short-term memory tasks only reflect activated long-term memory?

2003 ◽  
Vol 26 (6) ◽  
pp. 746-747 ◽  
Author(s):  
Steve Majerus ◽  
Martial Van der Linden ◽  
Fabienne Collette ◽  
Eric Salmon
Keyword(s):  
Semantic Processing ◽  
Short Term Memory ◽  
Brain Regions ◽  
Active Part ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Rule Out

We challenge Ruchkin et al.'s claim in reducing short-term memory (STM) to the active part of long-term memory (LTM), by showing that their data cannot rule out the possibility that activation of posterior brain regions could also reflect the contribution of a verbal STM buffer.

scholarly journals Tolerance to neurochemical and behavioral effects of the hallucinogen 25I-NBOMe

2021 ◽  
Author(s):  
Monika Herian ◽  
Mateusz Skawski ◽  
Adam Wojtas ◽  
Małgorzata K. Sobocińska ◽  
Karolina Noworyta ◽  
...  
Keyword(s):  
Short Term Memory ◽  
Day Treatment ◽  
Glutamate Release ◽  
Chronic Administration ◽  
Brain Regions ◽  
Acute Administration ◽  
Challenge Dose ◽  
Short Term ◽  
Term Memory ◽  
Acute Dose

Abstract Rationale 4-Iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (25I-NBOMe) is a potent serotonin 5-HT2A/2C receptor agonist with hallucinogenic activity. There is no data on the 25I-NBOMe effect on brain neurotransmission and animal performance after chronic administration. Objectives We examined the effect of a 7-day treatment with 25I-NBOMe (0.3 mg/kg/day) on neurotransmitters’ release and rats’ behavior in comparison to acute dose. Methods Changes in dopamine (DA), serotonin (5-HT), acetylcholine (ACh), and glutamate release were studied using microdialysis in freely moving rats. The hallucinogenic activity was measured in the wet dog shake (WDS) test. The animal locomotion was examined in the open field (OF) test, short-term memory in the novel object recognition (NOR) test. The anxiogenic/anxiolytic properties of the drug were tested using the light/dark box (LDB) test. Results Repeated administration of 25I-NBOMe decreased the response to a challenge dose of DA, 5-HT, and glutamatergic neurons in the frontal cortex as well as weakened the hallucinogenic activity in comparison to acute dose. In contrast, striatal and accumbal DA and 5-HT release and accumbal but not striatal glutamate release in response to the challenge dose of 25I-NBOMe was increased in comparison to acute treatment. The ACh release was increased in all brain regions. Behavioral tests showed a motor activity reduction and memory deficiency in comparison to a single dose and induction of anxiety after the drug’s chronic and acute administration. Conclusions Our findings suggest that multiple injections of 25I-NBOMe induce tolerance to hallucinogenic activity and produce alterations in neurotransmission. 25I-NBOMe effect on short-term memory, locomotor function, and anxiety seems to be the result of complex interactions between neurotransmitter pathways.

scholarly journals The neural basis of precise visual short-term memory for complex recognisable objects

2016 ◽  
Author(s):  
Michele Veldsman ◽  
Daniel J. Mitchell ◽  
Rhodri Cusack
Keyword(s):  
Short Term Memory ◽  
Brain Regions ◽  
Core Network ◽  
Neural Basis ◽  
Short Term ◽  
Term Memory ◽  
Photographic Images ◽  
Visual Short Term Memory ◽  
Stimulus Generation ◽  
The Impact

AbstractRecent evidence suggests that visual short-term memory (VSTM) capacity estimated using simple objects, such as colours and oriented bars, may not generalise well to more naturalistic stimuli. More visual detail can be stored in VSTM when complex, recognisable objects are maintained compared to simple objects. It is not yet known if it is recognisability that enhances memory precision, nor whether maintenance of recognisable objects is achieved with the same network of brain regions supporting maintenance of simple objects.We used a novel stimulus generation method to parametrically warp photographic images along a continuum, allowing separate estimation of the precision of memory representations and the number of items retained. The stimulus generation method was also designed to create unrecognisable, though perceptually matched, stimuli, to investigate the impact of recognisability on VSTM. We adapted the widely-used change detection and continuous report paradigms for use with complex, photographic images.Across three functional magnetic resonance imaging (fMRI) experiments, we demonstrated greater precision for recognisable objects in VSTM compared to unrecognisable objects. This clear behavioural advantage was not the result of recruitment of additional brain regions, or of stronger mean activity within the core network. Representational similarity analysis revealed greater variability across item repetitions in the representations of recognisable, compared to unrecognisable complex objects. We therefore propose that a richer range of neural representations support VSTM for complex recognisable objects.

scholarly journals Auditory hallucinations activate language and verbal short-term memory, but not auditory, brain regions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paola Fuentes-Claramonte ◽  
Joan Soler-Vidal ◽  
Pilar Salgado-Pineda ◽  
María Ángeles García-León ◽  
Nuria Ramiro ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Short Term Memory ◽  
Brain Regions ◽  
Short Term ◽  
Term Memory ◽  
Hearing Voices ◽  
Auditory Verbal Hallucinations ◽  
Cognitive Influences ◽  
Novel Variant ◽  
Capture Technique

AbstractAuditory verbal hallucinations (AVH, ‘hearing voices’) are an important symptom of schizophrenia but their biological basis is not well understood. One longstanding approach proposes that they are perceptual in nature, specifically that they reflect spontaneous abnormal neuronal activity in the auditory cortex, perhaps with additional ‘top down’ cognitive influences. Functional imaging studies employing the symptom capture technique—where activity when patients experience AVH is compared to times when they do not—have had mixed findings as to whether the auditory cortex is activated. Here, using a novel variant of the symptom capture technique, we show that the experience of AVH does not induce auditory cortex activation, even while real speech does, something that effectively rules out all theories that propose a perceptual component to AVH. Instead, we find that the experience of AVH activates language regions and/or regions that are engaged during verbal short-term memory.

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