scholarly journals Selectively increasing GHS-R1a expression in dCA1 excitatory/inhibitory neurons have opposite effects on memory encoding

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nan Li ◽  
Na Li ◽  
Fenghua Xu ◽  
Ming Yu ◽  
Zichen Qiao ◽  
...  

Abstract Aim Growth hormone secretagogue receptor 1a (GHS-R1a) is widely distributed in brain including the hippocampus. Studies have demonstrated the critical role of hippocampal ghrelin/GHS-R1a signaling in synaptic physiology, memory and cognitive dysfunction associated with Alzheimer’s disease (AD). However, current reports are inconsistent, and the mechanism underlying memory modulation of GHS-R1a signaling is uncertain. In this study, we aim to investigate the direct impact of selective increase of GHS-R1a expression in dCA1 excitatory/inhibitory neurons on learning and memory. Methods Endogenous GHS-R1a distribution in dCA1 excitatory/inhibitory neurons was assessed by fluorescence in situ hybridization. Cre-dependent GHS-R1a overexpression in excitatory or inhibitory neurons was done by stereotaxic injection of aav-hSyn-DIO-hGhsr1a-2A-eGFP virus in dCA1 region of vGlut1-Cre or Dlx5/6-Cre mice respectively. Virus-mediated GHS-R1a upregulation in dCA1 neurons was confirmed by quantitative RT-PCR. Different behavioral paradigms were used to evaluate long-term memory performance. Results GHS-R1a is distributed both in dCA1 excitatory pyramidal neurons (αCaMKII+) and in inhibitory interneurons (GAD67+). Selective increase of GHS-R1a expression in dCA1 pyramidal neurons impaired spatial memory and object-place recognition memory. In contrast, selective increase of GHS-R1a expression in dCA1 interneurons enhanced long-term memory performance. Our findings reveal, for the first time, a neuronal type-specific role that hippocampal GHS-R1a signaling plays in regulating memory. Therefore, manipulating GHS-R1a expression/activity in different subpopulation of neurons may help to clarify current contradictory findings and to elucidate mechanism of memory control by ghrelin/GHS-R1a signaling, under both physiological and pathological conditions such as AD.

Author(s):  
Ian Neath ◽  
Jean Saint-Aubin ◽  
Tamra J. Bireta ◽  
Andrew J. Gabel ◽  
Chelsea G. Hudson ◽  
...  

2019 ◽  
Author(s):  
Hayden Schill ◽  
Jeremy Wolfe ◽  
Timothy F. Brady

Memory capacity depends on prior knowledge, both in working memory and in long-term memory. For example, radiologists have improved long-term memory for medical images compared to novices. Furthermore, people tend to remember abnormal or surprising items best. This is often claimed to arise primarily because such items attract additional attention at encoding. How do expertise and abnormality interact when experts are actively searching for abnormalities; e.g. radiologists looking at mammograms? In the current work, we investigate whether expert radiologists (N=32) show improved memory performance for abnormal images compared to novice participants (N=60). We consider two types of “abnormality.” A mammogram can have a focal abnormality that can be localized or it could simply be the mammogram of a woman known to have cancer (e.g. the image of the breast contralateral to the focal abnormality). Must an image have a focal abnormality for additional attentional processing to be engaged? We found that experts have better memory for mammograms than novice participants and enhanced memory for abnormal images relative to normal images. Overall, radiologists showed no memory benefit for the contralateral-abnormal images and did not discriminate them from normal images, but had enhanced memory for images with focal abnormalities. Our results suggest that focal abnormalities play an important role in enhancing memory of expert observers.


2018 ◽  
Author(s):  
Lea M. Bartsch ◽  
Vanessa M. Loaiza ◽  
Lutz Jäncke ◽  
Klaus Oberauer ◽  
Jarrod A. Lewis-Peacock

AbstractMaintenance of information in working memory (WM) is assumed to rely on refreshing and elaboration, but clear mechanistic descriptions of these cognitive processes are lacking, and it is unclear whether they are simply two labels for the same process. This fMRI study investigated the extent to which refreshing, elaboration, and repeating of items in WM are distinct neural processes with dissociable behavioral outcomes in WM and long-term memory (LTM). Multivariate pattern analyses of fMRI data revealed differentiable neural signatures for these processes, which we also replicated in an independent sample of older adults. In some cases, the degree of neural separation within an individual predicted their memory performance. Elaboration improved LTM, but not WM, and this benefit increased as its neural signature became more distinct from repetition. Refreshing had no impact on LTM, but did improve WM, although the neural discrimination of this process was not predictive of the degree of improvement. These results demonstrate that refreshing and elaboration are separate processes that differently contribute to memory performance.HighlightsRepeated reading, refreshing, and elaboration are differentiable in brain activation patterns in both young and older adults.Elaboration selectively improved long-term memory for young adults, and the size of the benefit was related to the neural separability of elaboration from other processes.Older adults implemented a sub-optimal form of elaboration, and this may be a factor contributing to age-related deficits in long-term memory.Ethics statementThe study was approved by the ethical review board of the canton of Zurich (BASEC-No. 2017-00190) and all subjects gave informed written consent in accordance with the Declaration of Helsinki.Data and code availability statementAll behavioral data and analysis scripts can be assessed on the Open Science Framework (osf.io/p2h8b/). The fMRI data that support the findings of this study are available on request from the corresponding author, LMB. The fMRI data are not publicly available due to restrictions of the Swiss Ethics Committees on research involving humans regarding data containing information that could compromise the privacy of research participants.


2020 ◽  
Vol 16 ◽  
pp. 1-15
Author(s):  
Norwardatun Mohamed Razali

Colours are mentioned many times in the Holy Qur’an. Some are mentioned as colours in general, and some of them in specific; yellow, white, black, red, green and blue. Each colour has its special connotations in the Holy Qur’an and among these colours, yellow and red are considered as warm colours. This study aimed to find the significance of warm colours in the Holy Qur’an and its relationship to human psychology; focusing on memory performance. This research had used an inductive approach in terms of selecting Quranic verses; in which yellow and red colour were mentioned. These verses were then analysed by referring to the books of exegetical considerations in order to know the implications of these colours’ usage, as well as referring to psychology books and scientific articles. The research found that yellow and red colour in the Holy Qur’an mostly indicate attracting attention or pleasing viewers. Some examples included the yellow colour in resemblance to the colour of the cow, attention to decay and destruction such as yellow colour in the withering plants, and attention to resurrection like the red colour resembling scene of the Day of Resurrection. This indication in the Holy Qur’an is consistent with psychologists’ discovery; warm colours such as red and yellow are more effective and attractive in the process of transferring information from external to sensory memory, and thus to short-term and long-term memory.


2020 ◽  
Vol 32 (9) ◽  
pp. 1780-1795 ◽  
Author(s):  
Nicholas A. Ruiz ◽  
Michael R. Meager ◽  
Sachin Agarwal ◽  
Mariam Aly

The medial temporal lobe (MTL) is traditionally considered to be a system that is specialized for long-term memory. Recent work has challenged this notion by demonstrating that this region can contribute to many domains of cognition beyond long-term memory, including perception and attention. One potential reason why the MTL (and hippocampus specifically) contributes broadly to cognition is that it contains relational representations—representations of multidimensional features of experience and their unique relationship to one another—that are useful in many different cognitive domains. Here, we explore the hypothesis that the hippocampus/MTL plays a critical role in attention and perception via relational representations. We compared human participants with MTL damage to healthy age- and education-matched individuals on attention tasks that varied in relational processing demands. On each trial, participants viewed two images (rooms with paintings). On “similar room” trials, they judged whether the rooms had the same spatial layout from a different perspective. On “similar art” trials, they judged whether the paintings could have been painted by the same artist. On “identical” trials, participants simply had to detect identical paintings or rooms. MTL lesion patients were significantly and selectively impaired on the similar room task. This work provides further evidence that the hippocampus/MTL plays a ubiquitous role in cognition by virtue of its relational and spatial representations and highlights its important contributions to rapid perceptual processes that benefit from attention.


2016 ◽  
Vol 21 (4) ◽  
pp. 267-283 ◽  
Author(s):  
Timo Skodzik ◽  
Heinz Holling ◽  
Anya Pedersen

Objective: Memory problems are a frequently reported symptom in adult ADHD, and it is well-documented that adults with ADHD perform poorly on long-term memory tests. However, the cause of this effect is still controversial. The present meta-analysis examined underlying mechanisms that may lead to long-term memory impairments in adult ADHD. Method: We performed separate meta-analyses of measures of memory acquisition and long-term memory using both verbal and visual memory tests. In addition, the influence of potential moderator variables was examined. Results: Adults with ADHD performed significantly worse than controls on verbal but not on visual long-term memory and memory acquisition subtests. The long-term memory deficit was strongly statistically related to the memory acquisition deficit. In contrast, no retrieval problems were observable. Conclusion: Our results suggest that memory deficits in adult ADHD reflect a learning deficit induced at the stage of encoding. Implications for clinical and research settings are presented.


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