Complementary roles of medial temporal lobes and mid-dorsolateral prefrontal cortex for working memory for novel and familiar trial-unique visual stimuli

2012 ◽  
Vol 37 (4) ◽  
pp. 668-678 ◽  
Author(s):  
Karin Schon ◽  
Robert S. Ross ◽  
Michael E. Hasselmo ◽  
Chantal E. Stern
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Visual Stimuli ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Dorsolateral Prefrontal

scholarly journals Effects of β-Lactolin on Regional Cerebral Blood Flow within the Dorsolateral Prefrontal Cortex during Working Memory Task in Healthy Adults: A Randomized Controlled Trial

2021 ◽  
Vol 10 (3) ◽  
pp. 480
Author(s):  
Yasuhisa Ano ◽  
Masahiro Kita ◽  
Keiko Kobayashi ◽  
Takashi Koikeda ◽  
Ryuta Kawashima
Keyword(s):  
Working Memory ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Prefrontal Cortex ◽  
Regional Cerebral Blood Flow ◽  
Dorsolateral Prefrontal Cortex ◽  
Healthy Adults ◽  
Regional Cerebral Blood ◽  
Total Hemoglobin ◽  
Dorsolateral Prefrontal

Epidemiological studies have reported that consumption of dairy products rich in β-lactolin is beneficial for cognitive decline among elderly individuals. Although previous studies have shown that β-lactolin supplementation improves memory function and attention in healthy adults, the mechanism through which β-lactolin affects human brain function has yet to be elucidated. This placebo-controlled randomized double-blind study therefore examined the effects of β-lactolin on human regional cerebral blood flow (rCBF) using near-infrared spectroscopy (NIRS) according to the Consolidated Standards of Reporting Trials guidelines. A total of 114 healthy participants aged between 50 and 75 years with relatively low cognition were randomly allocated into the β-lactolin or placebo groups (n = 57 for both groups) and received supplementation for 6 weeks. After the 6 weeks of supplementation, total hemoglobin during cognitive tasks (Kraepelin and 2-back tasks) was measured using two-channel NIRS to determine rCBF. Accordingly, the β-lactolin group had significantly higher changes in total hemoglobin at the left dorsolateral prefrontal cortex (DLPFC) area measured using the left-side channel during the 2-back tasks (p = 0.027) compared to the placebo group. The present study suggests that β-lactolin supplementation increases rCBF and DLPFC activity during working memory tasks.

scholarly journals Prefrontal and Parietal Attractor Networks Mediate Working Memory Judgments

2020 ◽  
Author(s):  
Sihai Li ◽  
Christos Constantinidis ◽  
Xue-Lian Qi
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Critical Role ◽  
Memory Task ◽  
Delayed Response ◽  
Persistent Activity ◽  
Neural Basis ◽  
Brain Areas ◽  
Dorsolateral Prefrontal

ABSTRACTThe dorsolateral prefrontal cortex plays a critical role in spatial working memory and its activity predicts behavioral responses in delayed response tasks. Here we addressed whether this predictive ability extends to categorical judgments based on information retained in working memory, and is present in other brain areas. We trained monkeys in a novel, Match-Stay, Nonmatch-Go task, which required them to observe two stimuli presented in sequence with an intervening delay period between them. If the two stimuli were different, the monkeys had to saccade to the location of the second stimulus; if they were the same, they held fixation. Neurophysiological recordings were performed in areas 8a and 46 of the dlPFC and 7a and lateral intraparietal cortex (LIP) of the PPC. We hypothesized that random drifts causing the peak activity of the network to move away from the first stimulus location and towards the location of the second stimulus would result in categorical errors. Indeed, for both areas, when the first stimulus appeared in a neuron’s preferred location, the neuron showed significantly higher firing rates in correct than in error trials. When the first stimulus appeared at a nonpreferred location and the second stimulus at a preferred, activity in error trials was higher than in correct. The results indicate that the activity of both dlPFC and PPC neurons is predictive of categorical judgments of information maintained in working memory, and the magnitude of neuronal firing rate deviations is revealing of the contents of working memory as it determines performance.SIGNIFICANCE STATEMENTThe neural basis of working memory and the areas mediating this function is a topic of controversy. Persistent activity in the prefrontal cortex has traditionally been thought to be the neural correlate of working memory, however recent studies have proposed alternative mechanisms and brain areas. Here we show that persistent activity in both the dorsolateral prefrontal cortex and posterior parietal cortex predicts behavior in a working memory task that requires a categorical judgement. Our results offer support to the idea that a network of neurons in both areas act as an attractor network that maintains information in working memory, which informs behavior.

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