scholarly journals Posterior Parietal Cortex Dysfunction Is Central to Working Memory Storage and Broad Cognitive Deficits in Schizophrenia

2018 ◽  
Vol 38 (39) ◽  
pp. 8378-8387 ◽  
Author(s):  
Britta Hahn ◽  
Benjamin M. Robinson ◽  
Carly J. Leonard ◽  
Steven J. Luck ◽  
James M. Gold
Keyword(s):  
Working Memory ◽  
Parietal Cortex ◽  
Cognitive Deficits ◽  
Posterior Parietal Cortex ◽  
Memory Storage ◽  
Posterior Parietal

17. Blunted Tuning of Posterior Parietal Cortex Activity is Central to Working Memory Storage Deficits in Schizophrenia

2019 ◽  
Vol 85 (10) ◽  
pp. S7
Author(s):  
Britta Hahn ◽  
Molly Erickson ◽  
Benjamin Robinson ◽  
Carly Leonard ◽  
Steven Luck ◽  
...  
Keyword(s):  
Working Memory ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Memory Storage ◽  
Posterior Parietal

Effects of High-Definition Transcranial Direct Current Stimulation and Theta Burst Stimulation for Modulating the Posterior Parietal Cortex

2019 ◽  
Vol 25 (09) ◽  
pp. 972-984
Author(s):  
Tian Gan ◽  
Stevan Nikolin ◽  
Colleen K. Loo ◽  
Donel M. Martin
Keyword(s):  
Working Memory ◽  
Parietal Cortex ◽  
Direct Current ◽  
Posterior Parietal Cortex ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
High Definition ◽  
Attention Task ◽  
Posterior Parietal ◽  
Theta Burst

AbstractObjectives:Noninvasive brain stimulation methods, including high-definition transcranial direct current stimulation (HD-tDCS) and theta burst stimulation (TBS) have emerged as novel tools to modulate and explore brain function. However, the relative efficacy of these newer stimulation approaches for modulating cognitive functioning remains unclear. This study investigated the cognitive effects of HD-tDCS, intermittent TBS (iTBS) and prolonged continuous TBS (ProcTBS) and explored the potential of these approaches for modulating hypothesized functions of the left posterior parietal cortex (PPC).Methods:Twenty-two healthy volunteers attended four experimental sessions in a cross-over experimental design. In each session, participants either received HD-tDCS, iTBS, ProcTBS or sham, and completed cognitive tasks, including a divided attention task, a working memory maintenance task and an attention task (emotional Stroop test).Results:The results showed that compared to sham, HD-tDCS, iTBS and ProcTBS caused significantly faster response times on the emotional Stroop task. The effect size (Cohen’sd) wasd= .32 for iTBS (p< .001), .21 for ProcTBS (p= .01) and .15 for HD-tDCS (p= .044). However, for the performance on the divided attention and working memory maintenance tasks, no significant effect of stimulation was found.Conclusions:The results suggest that repetitive transcranial magnetic stimulation techniques, including TBS, may have greater efficacy for modulating cognition compared with HD-tDCS, and extend existing knowledge about specific functions of the left PPC.

scholarly journals Neural correlates of visuospatial working memory in the ‘at-risk mental state’

2010 ◽  
Vol 40 (12) ◽  
pp. 1987-1999 ◽  
Author(s):  
M. R. Broome ◽  
P. Fusar-Poli ◽  
P. Matthiasson ◽  
J. B. Woolley ◽  
L. Valmaggia ◽  
...  
Keyword(s):  
At Risk ◽  
Working Memory ◽  
Frontal Cortex ◽  
Parietal Cortex ◽  
Mental State ◽  
Posterior Parietal Cortex ◽  
Group Differences ◽  
First Episode ◽  
Posterior Parietal ◽  
At Risk Mental State

BackgroundImpaired spatial working memory (SWM) is a robust feature of schizophrenia and has been linked to the risk of developing psychosis in people with an at-risk mental state (ARMS). We used functional magnetic resonance imaging (fMRI) to examine the neural substrate of SWM in the ARMS and in patients who had just developed schizophrenia.MethodfMRI was used to study 17 patients with an ARMS, 10 patients with a first episode of psychosis and 15 age-matched healthy comparison subjects. The blood oxygen level-dependent (BOLD) response was measured while subjects performed an object–location paired-associate memory task, with experimental manipulation of mnemonic load.ResultsIn all groups, increasing mnemonic load was associated with activation in the medial frontal and medial posterior parietal cortex. Significant between-group differences in activation were evident in a cluster spanning the medial frontal cortex and right precuneus, with the ARMS groups showing less activation than controls but greater activation than first-episode psychosis (FEP) patients. These group differences were more evident at the most demanding levels of the task than at the easy level. In all groups, task performance improved with repetition of the conditions. However, there was a significant group difference in the response of the right precuneus across repeated trials, with an attenuation of activation in controls but increased activation in FEP and little change in the ARMS.ConclusionsAbnormal neural activity in the medial frontal cortex and posterior parietal cortex during an SWM task may be a neural correlate of increased vulnerability to psychosis.

scholarly journals Working Memory Retrieval: Contributions of the Left Prefrontal Cortex, the Left Posterior Parietal Cortex, and the Hippocampus

2009 ◽  
Vol 21 (3) ◽  
pp. 581-593 ◽  
Author(s):  
Ilke Öztekin ◽  
Brian McElree ◽  
Bernhard P. Staresina ◽  
Lila Davachi
Keyword(s):  
Working Memory ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Inferior Frontal Gyrus ◽  
Long Term Memory ◽  
Term Memory ◽  
Focal Attention ◽  
Left Posterior ◽  
Posterior Parietal

Functional magnetic resonance imaging was used to identify regions involved in working memory (WM) retrieval. Neural activation was examined in two WM tasks: an item recognition task, which can be mediated by a direct-access retrieval process, and a judgment of recency task that requires a serial search. Dissociations were found in the activation patterns in the hippocampus and in the left inferior frontal gyrus (LIFG) when the probe contained the most recently studied serial position (where a test probe can be matched to the contents of focal attention) compared to when it contained all other positions (where retrieval is required). The data implicate the hippocampus and the LIFG in retrieval from WM, complementing their established role in long-term memory. Results further suggest that the left posterior parietal cortex (LPPC) supports serial retrieval processes that are often required to recover temporal order information. Together, these data suggest that the LPPC, the LIFG, and the hippocampus collectively support WM retrieval. Critically, the reported findings support accounts that posit a distinction between representations maintained in and outside of focal attention, but are at odds with traditional dual-store models that assume distinct mechanisms for short- and long-term memory representations.

Neglecting the posterior parietal cortex: The role of higher-order perceptual memories for working-memory retention

2003 ◽  
Vol 26 (6) ◽  
pp. 749-749 ◽  
Author(s):  
Axel Mecklinger ◽  
Bertram Opitz
Keyword(s):  
Working Memory ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Higher Order ◽  
Fmri Data ◽  
Memory Retention ◽  
Memory Representations ◽  
Posterior Parietal ◽  
Dynamic Link

The view that posterior brain systems engaged in lower-order perceptual functions are activated during sustained retention is challenged by fMRI data, which show consistent retention-related activation of higher-order memory representations for a variety of working-memory materials. Sustained retention entails the dynamic link of these higher-order memories with schemata for goal-oriented action housed by the frontal lobes.

scholarly journals Neurons with inverted tuning during the delay periods of working memory tasks in the dorsal prefrontal and posterior parietal cortex

2012 ◽  
Vol 108 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Xin Zhou ◽  
Fumi Katsuki ◽  
Xue-Lian Qi ◽  
Christos Constantinidis
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Memory Task ◽  
Functional Difference ◽  
Initial Stimulus ◽  
Cortical Afferents ◽  
Dorsolateral Prefrontal ◽  
Posterior Parietal

The dorsolateral prefrontal and posterior parietal cortices are two interconnected brain areas that are coactivated in tasks involving functions such as spatial attention and working memory. The response properties of neurons in the two areas are in many respects indistinguishable, yet only prefrontal neurons are able to resist interference by distracting stimuli when subjects are required to remember an initial stimulus. Several mechanisms have been proposed that could account for this functional difference, including the existence of specialized interneuron types, specific to the prefrontal cortex. Although such neurons with inverted tuning during the delay period of a working memory task have been described in the prefrontal cortex, no comparative data exist from other cortical areas that would establish a unique prefrontal role. To test this hypothesis, we analyzed a large database of recordings obtained in the dorsolateral prefrontal and posterior parietal cortex of the same monkeys as they performed working memory tasks. We found that in the prefrontal cortex, neurons with inverted tuning were more numerous and manifested unique properties. Our results give credence to the idea that a division of labor exists between separate neuron types in the prefrontal cortex and that this represents a functional specialization that is not present in its cortical afferents.

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