The prefrontal cortex

2020 ◽  
pp. 505-526
Author(s):  
Edmund T. Rolls

The prefrontal cortex receives perceptual information from the temporal and parietal cortices, and is in a position to perform ‘off-line’ processing, including holding items in a short-term memory when the items are no longer present in the input processing streams. This off-line capacity develops into a capability of manipulating and rearranging items in short-term memory, and this is called working memory, which is also implemented in the prefrontal cortex. This ability in humans develops into systems that can plan ahead, and then can control behaviour according to such plans, which is referred to as ‘executive function’. Attractor networks are fundamental to understanding the functions of the prefrontal cortex in short-term and working memory; and in providing the source of the top-down bias in top-down models of attention

2003 ◽  
Vol 26 (6) ◽  
pp. 709-728 ◽  
Author(s):  
Daniel S. Ruchkin ◽  
Jordan Grafman ◽  
Katherine Cameron ◽  
Rita S. Berndt

High temporal resolution event-related brain potential and electroencephalographic coherence studies of the neural substrate of short-term storage in working memory indicate that the sustained coactivation of both prefrontal cortex and the posterior cortical systems that participate in the initial perception and comprehension of the retained information are involved in its storage. These studies further show that short-term storage mechanisms involve an increase in neural synchrony between prefrontal cortex and posterior cortex and the enhanced activation of long-term memory representations of material held in short-term memory. This activation begins during the encoding/comprehension phase and evidently is prolonged into the retention phase by attentional drive from prefrontal cortex control systems. A parsimonious interpretation of these findings is that the long-term memory systems associated with the posterior cortical processors provide the necessary representational basis for working memory, with the property of short-term memory decay being primarily due to the posterior system. In this view, there is no reason to posit specialized neural systems whose functions are limited to those of short-term storage buffers. Prefrontal cortex provides the attentional pointer system for maintaining activation in the appropriate posterior processing systems. Short-term memory capacity and phenomena such as displacement of information in short-term memory are determined by limitations on the number of pointers that can be sustained by the prefrontal control systems.


2021 ◽  
Vol 12 ◽  
Author(s):  
Osvaldo M. Basmadjian ◽  
Victoria B. Occhieppo ◽  
Natalia A. Marchese ◽  
M. Jazmin Silvero C. ◽  
María Cecilia Becerra ◽  
...  

Background: Amphetamine (AMPH) alters neurons, glia and microvessels, which affects neurovascular unit coupling, leading to disruption in brain functions such as attention and working memory. Oxidative stress plays a crucial role in these alterations. The angiotensin type I receptors (AT1-R) mediate deleterious effects, such as oxidative/inflammatory responses, endothelial dysfunction, neuronal oxidative damage, alterations that overlap with those observed from AMPH exposure.Aims: The aim of this study was to evaluate the AT1-R role in AMPH-induced oxidative stress and glial and vascular alterations in the prefrontal cortex (PFC). Furthermore, we aimed to evaluate the involvement of AT1-R in the AMPH-induced short-term memory and working memory deficit.Methods: Male Wistar rats were repeatedly administered with the AT1-R blocker candesartan (CAND) and AMPH. Acute oxidative stress in the PFC was evaluated immediately after the last AMPH administration by determining lipid and protein peroxidation. After 21 off-drug days, long-lasting alterations in the glia, microvessel architecture and to cognitive tasks were evaluated by GFAP, CD11b and von Willebrand immunostaining and by short-term and working memory assessment.Results: AMPH induced acute oxidative stress, long-lasting glial reactivity in the PFC and a working memory deficit that were prevented by AT1-R blockade pretreatment. Moreover, AMPH induces transient angiogenesis in PFC via AT1-R. AMPH did not affect short-term memory.Conclusion: Our results support the protective role of AT1-R blockade in AMPH-induced oxidative stress, transient angiogenesis and long-lasting glial activation, preserving working memory performance.


2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.


2020 ◽  
Vol 63 (12) ◽  
pp. 4162-4178
Author(s):  
Emily Jackson ◽  
Suze Leitão ◽  
Mary Claessen ◽  
Mark Boyes

Purpose Previous research into the working, declarative, and procedural memory systems in children with developmental language disorder (DLD) has yielded inconsistent results. The purpose of this research was to profile these memory systems in children with DLD and their typically developing peers. Method One hundred four 5- to 8-year-old children participated in the study. Fifty had DLD, and 54 were typically developing. Aspects of the working memory system (verbal short-term memory, verbal working memory, and visual–spatial short-term memory) were assessed using a nonword repetition test and subtests from the Working Memory Test Battery for Children. Verbal and visual–spatial declarative memory were measured using the Children's Memory Scale, and an audiovisual serial reaction time task was used to evaluate procedural memory. Results The children with DLD demonstrated significant impairments in verbal short-term and working memory, visual–spatial short-term memory, verbal declarative memory, and procedural memory. However, verbal declarative memory and procedural memory were no longer impaired after controlling for working memory and nonverbal IQ. Declarative memory for visual–spatial information was unimpaired. Conclusions These findings indicate that children with DLD have deficits in the working memory system. While verbal declarative memory and procedural memory also appear to be impaired, these deficits could largely be accounted for by working memory skills. The results have implications for our understanding of the cognitive processes underlying language impairment in the DLD population; however, further investigation of the relationships between the memory systems is required using tasks that measure learning over long-term intervals. Supplemental Material https://doi.org/10.23641/asha.13250180


1997 ◽  
Author(s):  
Randall W. Engle ◽  
Stephen Tuholski ◽  
James Laughlin ◽  
Andrew Conway

Author(s):  
Steven J Hardy ◽  
Sarah E Bills ◽  
Emily R Meier ◽  
Jeffrey C Schatz ◽  
Katie J Keridan ◽  
...  

Abstract Objective Youth with sickle cell disease (SCD) are at risk for neurocognitive deficits including problems with working memory (WM), but few interventions to improve functioning exist. This study sought to determine the feasibility and efficacy of home-based, digital WM training on short-term memory and WM, behavioral outcomes, and academic fluency using a parallel group randomized controlled trial design. Methods 47 children (7–16 years) with SCD and short-term memory or WM difficulties were randomized to Cogmed Working Memory Training at home on a tablet device (N = 24) or to a standard care Waitlist group (N = 23) that used Cogmed after the waiting period. Primary outcomes assessed in clinic included performance on verbal and nonverbal short-term memory and WM tasks. Secondary outcomes included parent-rated executive functioning and tests of math and reading fluency. Results In the evaluable sample, the Cogmed group (N = 21) showed greater improvement in visual WM compared with the Waitlist group (N = 22; p = .03, d = 0.70 [CI95 = 0.08, 1.31]). When examining a combined sample of participants, those who completed ≥10 training sessions exhibited significant improvements in verbal short-term memory, visual WM, and math fluency. Adherence to Cogmed was lower than expected (M = 9.07 sessions, SD = 7.77), with 19 participants (41%) completing at least 10 sessions. Conclusions: Visual WM, an ability commonly affected by SCD, is modifiable with cognitive training. Benefits extended to verbal short-term memory and math fluency when patients completed a sufficient training dose. Additional research is needed to identify ideal candidates for training and determine whether training gains are sustainable and generalize to real-world outcomes.


Author(s):  
Francesco Panico ◽  
Stefania De Marco ◽  
Laura Sagliano ◽  
Francesca D’Olimpio ◽  
Dario Grossi ◽  
...  

AbstractThe Corsi Block-Tapping test (CBT) is a measure of spatial working memory (WM) in clinical practice, requiring an examinee to reproduce sequences of cubes tapped by an examiner. CBT implies complementary behaviors in the examiners and the examinees, as they have to attend a precise turn taking. Previous studies demonstrated that the Prefrontal Cortex (PFC) is activated during CBT, but scarce evidence is available on the neural correlates of CBT in the real setting. We assessed PFC activity in dyads of examiner–examinee participants while completing the real version of CBT, during conditions of increasing and exceeding workload. This procedure allowed to investigate whether brain activity in the dyads is coordinated. Results in the examinees showed that PFC activity was higher when the workload approached or reached participants’ spatial WM span, and lower during workload conditions that were largely below or above their span. Interestingly, findings in the examiners paralleled the ones in the examinees, as examiners’ brain activity increased and decreased in a similar way as the examinees’ one. In the examiners, higher left-hemisphere activity was observed suggesting the likely activation of non-spatial WM processes. Data support a bell-shaped relationship between cognitive load and brain activity, and provide original insights on the cognitive processes activated in the examiner during CBT.


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