Maintenance and Manipulation in Working Memory: Differential Ventral and Dorsal Frontal Cortex fMRI Activity

2009 ◽  
Vol 41 (11) ◽  
pp. 1054-1062 ◽  
Author(s):  
Pudas Sara ◽  
Persson Jonas ◽  
Nilsson L-G ◽  
Nyberg Lars
Author(s):  
Jinzhuang Huang ◽  
Lei Xie ◽  
Ruiwei Guo ◽  
Jinhong Wang ◽  
Jinquan Lin ◽  
...  

Abstract Hemodialysis (HD) is associated with cognitive impairment in patients with end-stage renal disease (ESRD). However, the neural mechanism of spatial working memory (SWM) impairment in HD-ESRD patients remains unclear. We investigated the abnormal alterations in SWM-associated brain activity patterns in HD-ESRD patients using blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) technique during n-back tasks. Twenty-two HD-ESRD patients and 22 well-matched controls underwent an fMRI scan while undergoing a three-load n-back tasks with different difficulty levels. Cognitive and mental states were assessed using a battery of neuropsychologic tests. The HD-ESRD patients exhibited worse memory abilities than controls. Compared with the control group, the HD-ESRD patient group showed lower accuracy and longer response time under the n-back tasks, especially in the 2-back task. The patterns of brain activation changed under different working memory loads in the HD-ESRD patients, showing decreased activity in the right medial frontal gyrus and inferior frontal gyrus under 0-back and 1-back task, while more decreased activation in the bilateral frontal cortex, parietal lobule, anterior/posterior cingulate cortex and insula cortex under 2-back task. With the increase of task difficulty, the activation degree of the frontal and parietal cortex decreased. More importantly, we found that lower activation in frontal cortex and parietal lobule was associated with worse cognitive function in the HD-ESRD patients. These results demonstrate that the abnormal brain activity patterns of frontal cortex and parietal lobule may reflect the neural mediation of SWM impairment.


NeuroImage ◽  
1998 ◽  
Vol 7 (4) ◽  
pp. S12 ◽  
Author(s):  
A. M Owen ◽  
A.C.H. Lee ◽  
E.J. Williams ◽  
I.V. Kendall ◽  
S.P.M.J. Downey ◽  
...  

2018 ◽  
Vol 115 (5) ◽  
pp. 1117-1122 ◽  
Author(s):  
André M. Bastos ◽  
Roman Loonis ◽  
Simon Kornblith ◽  
Mikael Lundqvist ◽  
Earl K. Miller

All of the cerebral cortex has some degree of laminar organization. These different layers are composed of neurons with distinct connectivity patterns, embryonic origins, and molecular profiles. There are little data on the laminar specificity of cognitive functions in the frontal cortex, however. We recorded neuronal spiking/local field potentials (LFPs) using laminar probes in the frontal cortex (PMd, 8A, 8B, SMA/ACC, DLPFC, and VLPFC) of monkeys performing working memory (WM) tasks. LFP power in the gamma band (50–250 Hz) was strongest in superficial layers, and LFP power in the alpha/beta band (4–22 Hz) was strongest in deep layers. Memory delay activity, including spiking and stimulus-specific gamma bursting, was predominately in superficial layers. LFPs from superficial and deep layers were synchronized in the alpha/beta bands. This was primarily unidirectional, with alpha/beta bands in deep layers driving superficial layer activity. The phase of deep layer alpha/beta modulated superficial gamma bursting associated with WM encoding. Thus, alpha/beta rhythms in deep layers may regulate the superficial layer gamma bands and hence maintenance of the contents of WM.


1998 ◽  
Vol 95 (13) ◽  
pp. 7721-7726 ◽  
Author(s):  
A. M. Owen ◽  
C. E. Stern ◽  
R. B. Look ◽  
I. Tracey ◽  
B. R. Rosen ◽  
...  

1997 ◽  
Vol 20 (4) ◽  
pp. 756-757
Author(s):  
Gary W. Strong

What is encoded in working memory may be a content-addressable pointer, but a critical portion of the information that is addressed includes the motor information to achieve deictic reference in the environment. Additionally, the same strategy that is used to access environment information just in time for its use may also be used to access long-term memory via the pre-frontal cortex.


2020 ◽  
Author(s):  
Thomas D Prevot ◽  
Akiko Sumitomo ◽  
Toshifumi Tomoda ◽  
Daniel E Knutson ◽  
Guanguan Li ◽  
...  

Abstract Aging is associated with reduced brain volume, altered neural activity, and neuronal atrophy in cortical-like structures, comprising the frontal cortex and hippocampus, together contributing to cognitive impairments. Therapeutic efforts aimed at reversing these deficits have focused on excitatory or neurotrophic mechanisms, although recent findings show that reduced dendritic inhibition mediated by α5-subunit containing GABA-A receptors (α5-GABAA-Rs) occurs during aging and contributes to cognitive impairment. Here, we aimed to confirm the beneficial effect on working memory of augmenting α5-GABAA-R activity in old mice and tested its potential at reversing age-related neuronal atrophy. We show that GL-II-73, a novel ligand with positive allosteric modulatory activity at α5-GABAA-R (α5-PAM), increases dendritic branching complexity and spine numbers of cortical neurons in vitro. Using old mice, we confirm that α5-PAM reverses age-related working memory deficits and show that chronic treatment (3 months) significantly reverses age-related dendritic shrinkage and spine loss in frontal cortex and hippocampus. A subsequent 1-week treatment cessation (separate cohort) resulted in loss of efficacy on working memory but maintained morphological neurotrophic effects. Together, the results demonstrate the beneficial effect on working memory and neurotrophic efficacy of augmenting α5-GABAA-R function in old mice, suggesting symptomatic and disease-modifying potential in age-related brain disorders.


2010 ◽  
Vol 40 (12) ◽  
pp. 1987-1999 ◽  
Author(s):  
M. R. Broome ◽  
P. Fusar-Poli ◽  
P. Matthiasson ◽  
J. B. Woolley ◽  
L. Valmaggia ◽  
...  

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.


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