scholarly journals Sleep and hippocampal function during an associative memory task are influenced by surgical menopause at midlife

2021 ◽  
Vol 17 (S5) ◽  
Author(s):  
Alana Brown ◽  
Nicole J. Gervais ◽  
Laura Gravelsins ◽  
Gina Nicoll ◽  
Jenny Rieck ◽  
...  
Keyword(s):  
Associative Memory ◽  
Memory Task ◽  
Hippocampal Function ◽  
Surgical Menopause

038 Sleep and Hippocampal Function during an Associative Memory Task are Influenced by Surgical Menopause at Midlife

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A16-A17
Author(s):  
Alana Brown ◽  
Nicole Gervais ◽  
Laura Gravelsins ◽  
Gina Nicoll ◽  
Jenny Rieck ◽  
...  
Keyword(s):  
Associative Memory ◽  
Total Sleep Time ◽  
Memory Task ◽  
Sleep Time ◽  
Sleep Efficiency ◽  
Hippocampal Function ◽  
Younger Women ◽  
Memory Accuracy ◽  
Surgical Menopause ◽  
17Β Estradiol

Abstract Introduction 17β-estradiol loss is related to Alzheimer’s disease (AD) risk factors, including disordered sleep and associative memory decrements. Women have higher risk for AD than men, and those with mid-life 17β-estradiol loss due to surgical menopause, including bilateral salpingo-oophorectomy (BSO) before age 48, have even higher risk. We wondered whether sleep and associative memory in women with BSO (mean age 44–46) would be comparable to those with spontaneous/natural menopause (SM; mean age 57), and whether 17β-estradiol-based hormone therapy (ET) might mitigate these effects. Methods We assessed sleep using the average of three nights of portable polysomnography (Temec) in women with BSO either taking ET (BSO+ET; n=16), or not (BSO; n=18), and in older spontaneously menopausal women (SM; n=14). Using EEG (Fp1-Fp2), we obtained sleep staging automatically (Neurobit Technologies). Participants also completed a face-name associative memory task during functional magnetic resonance imaging. Recognition accuracy and brain activation during encoding were measured. Results BSO exhibited reduced sleep efficiency compared to BSO+ET. For BSO, there was no relationship between percent of total sleep time in N3 and hippocampal activation during associative encoding, even though percent of total sleep time in N3 was negatively associated with hippocampal activation during associative encoding in BSO+ET. For all groups, including BSO, lower latency to consolidated N3 correlated with better associative memory accuracy. There were no group differences in associative memory accuracy. In contrast to BSO, SM showed significantly longer latency to consolidated N3 than BSO+ET. Conclusion Younger women with BSO have comparable sleep to older women in SM. In younger women with BSO, ET improves sleep efficiency. Further, while associative memory may be disrupted by increased latency to consolidated N3 in all women, BSO and BSO+ET showed similar associative memory accuracy and latency to consolidated N3. Only BSO+ET exhibited a significant correlation between hippocampal activity during associative encoding and time spent in N3, indicating that ET may support the negative relationship between N3 and hippocampal function. Overall, ET in younger women with BSO potentially ameliorates poor sleep and associative memory decrements. Support (if any) Alzheimer’s Association/Brain Canada Foundation: AARF-17-504715; Wilfred and Joyce Posluns Chair in Women’s Brain Health and Aging

scholarly journals Inter-Rater Reliability of Preprocessing EEG Data: Impact of Subjective Artifact Removal on Associative Memory Task ERP Results

2017 ◽  
Vol 11 ◽  
Author(s):  
Steven D. Shirk ◽  
Donald G. McLaren ◽  
Jessica S. Bloomfield ◽  
Alex Powers ◽  
Alec Duffy ◽  
...  
Keyword(s):  
Associative Memory ◽  
Memory Task ◽  
Artifact Removal ◽  
Rater Reliability ◽  
Eeg Data

scholarly journals Theta-gamma coupling binds visual perceptual features in an associative memory task

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Moritz Köster ◽  
Holger Finger ◽  
Sebastian Graetz ◽  
Maren Kater ◽  
Thomas Gruber
Keyword(s):  
Associative Memory ◽  
Memory Task ◽  
Perceptual Features

scholarly journals Conjunctive representation of what and when in monkey hippocampus and lateral prefrontal cortex during an associative memory task

2019 ◽  
Author(s):  
Nathanael A. Cruzado ◽  
Zoran Tiganj ◽  
Scott L. Brincat ◽  
Earl K. Miller ◽  
Marc W. Howard
Keyword(s):  
Prefrontal Cortex ◽  
Associative Memory ◽  
Memory Task ◽  
Neural Recording ◽  
Temporal Coding ◽  
Adaptive Memory ◽  
Lateral Prefrontal Cortex ◽  
The Past ◽  
Large Numbers

AbstractAdaptive memory requires the organism to form associations that bridge between events separated in time. Many studies show interactions between hippocampus (HPC) and prefrontal cortex (PFC) during formation of such associations. We analyze neural recording from monkey HPC and PFC during a memory task that requires the monkey to associate stimuli separated by about a second in time. After the first stimulus was presented, large numbers of units in both HPC and PFC fired in sequence. Many units fired only when a particular stimulus was presented at a particular time in the past. These results indicate that both HPC and PFC maintain a temporal record of events that could be used to form associations across time. This temporal record of the past is a key component of the temporal coding hypothesis, a hypothesis in psychology that memory not only encodes what happened, but when it happened.

Functional Connectivity Relationships Predict Similarities in Task Activation and Pattern Information during Associative Memory Encoding

2014 ◽  
Vol 26 (5) ◽  
pp. 1085-1099 ◽  
Author(s):  
Maureen Ritchey ◽  
Andrew P. Yonelinas ◽  
Charan Ranganath
Keyword(s):  
Functional Connectivity ◽  
Functional Properties ◽  
Associative Memory ◽  
Large Scale ◽  
Memory Task ◽  
Neural Systems ◽  
General Level ◽  
Specific Information ◽  
Memory Encoding ◽  
Cortical Regions

Neural systems may be characterized by measuring functional interactions in the healthy brain, but it is unclear whether components of systems defined in this way share functional properties. For instance, within the medial temporal lobes (MTL), different subregions show different patterns of cortical connectivity. It is unknown, however, whether these intrinsic connections predict similarities in how these regions respond during memory encoding. Here, we defined brain networks using resting state functional connectivity (RSFC) then quantified the functional similarity of regions within each network during an associative memory encoding task. Results showed that anterior MTL regions affiliated with a network of anterior temporal cortical regions, whereas posterior MTL regions affiliated with a network of posterior medial cortical regions. Importantly, these connectivity relationships also predicted similarities among regions during the associative memory task. Both in terms of task-evoked activation and trial-specific information carried in multivoxel patterns, regions within each network were more similar to one another than were regions in different networks. These findings suggest that functional heterogeneity among MTL subregions may be related to their participation in distinct large-scale cortical systems involved in memory. At a more general level, the results suggest that components of neural systems defined on the basis of RSFC share similar functional properties in terms of recruitment during cognitive tasks and information carried in voxel patterns.

scholarly journals Transitional Versus Surgical Menopause in a Rodent Model: Etiology of Ovarian Hormone Loss Impacts Memory and the Acetylcholine System

Endocrinology ◽  
2009 ◽  
Vol 150 (9) ◽  
pp. 4248-4259 ◽  
Author(s):  
Jazmin I. Acosta ◽  
Loretta Mayer ◽  
Joshua S. Talboom ◽  
Candy Wing S. Tsang ◽  
Constance J. Smith ◽  
...  
Keyword(s):  
Memory Task ◽  
Acetylcholinesterase Activity ◽  
Rodent Model ◽  
Surgical Removal ◽  
Ovarian Hormone ◽  
Vinylcyclohexene Diepoxide ◽  
Menopausal Women ◽  
Surgical Menopause ◽  
Negative Effect ◽  
Brain Acetylcholinesterase

Abstract Clinical research suggests that type of ovarian hormone loss at menopause influences cognition. Until recently ovariectomy (OVX) has been the primary rodent model to examine effects of ovarian hormone loss on cognition. This model limits evaluations to abrupt and complete ovarian hormone loss, modeling less than 13% of women who receive surgical menopause. The majority of women do not have their ovaries surgically removed and undergo transitional hormone loss via ovarian follicular depletion. 4-Vinylcyclohexene-diepoxide (VCD) produces gradual ovarian follicular depletion in the rodent, with hormone profiles more similar to naturally menopausal women vs. OVX. We directly compared VCD and OVX models to examine whether type of hormone loss (transitional vs. surgical) impacted cognition as assessed on a maze battery as well as the cholinergic system tested via scopolamine mnemonic challenge and brain acetylcholinesterase activity. Middle-aged rats received either sham surgery, OVX surgery, VCD, or VCD then OVX to assess effects of removal of residual ovarian output after transitional menopause and follicular depletion. VCD-induced transitional menopause impaired learning of a spatial recent memory task; surgical removal of residual ovarian hormones by OVX abolished this negative effect of transitional menopause. Furthermore, transitional menopause before OVX was better for memory than an abrupt loss of hormones via OVX only. Surgical ovarian hormone loss, regardless of menopause history, increased hippocampal acetylcholinesterase activity. Circulating gonadotropin and androstenedione levels were related to cognitive competence. Collectively, findings suggest that in the rat, initiation of transitional menopause before surgical ovary removal can benefit mnemonic function and could obviate some negative cognitive consequences of surgical menopause alone.

scholarly journals Effects of Δ9-Tetrahydrocannabinol Administration on Human Encoding and Recall Memory Function: A Pharmacological fMRI Study

2012 ◽  
Vol 24 (3) ◽  
pp. 588-599 ◽  
Author(s):  
Matthijs G. Bossong ◽  
Gerry Jager ◽  
Hendrika H. van Hell ◽  
Lineke Zuurman ◽  
J. Martijn Jansma ◽  
...  
Keyword(s):  
Task Performance ◽  
Associative Memory ◽  
Animal Studies ◽  
Inferior Frontal Gyrus ◽  
Memory Function ◽  
Memory Task ◽  
Convincing Evidence ◽  
Compensatory Mechanism ◽  
Novel Target ◽  
The Right

Deficits in memory function are an incapacitating aspect of various psychiatric and neurological disorders. Animal studies have recently provided strong evidence for involvement of the endocannabinoid (eCB) system in memory function. Neuropsychological studies in humans have shown less convincing evidence but suggest that administration of cannabinoid substances affects encoding rather than recall of information. In this study, we examined the effects of perturbation of the eCB system on memory function during both encoding and recall. We performed a pharmacological MRI study with a placebo-controlled, crossover design, investigating the effects of Δ9-tetrahydrocannabinol (THC) inhalation on associative memory-related brain function in 13 healthy volunteers. Performance and brain activation during associative memory were assessed using a pictorial memory task, consisting of separate encoding and recall conditions. Administration of THC caused reductions in activity during encoding in the right insula, the right inferior frontal gyrus, and the left middle occipital gyrus and a network-wide increase in activity during recall, which was most prominent in bilateral cuneus and precuneus. THC administration did not affect task performance, but while during placebo recall activity significantly explained variance in performance, this effect disappeared after THC. These findings suggest eCB involvement in encoding of pictorial information. Increased precuneus activity could reflect impaired recall function, but the absence of THC effects on task performance suggests a compensatory mechanism. These results further emphasize the eCB system as a potential novel target for treatment of memory disorders and a promising target for development of new therapies to reduce memory deficits in humans.

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