scholarly journals The Role of Hierarchical Dynamical Functions in Coding for Episodic Memory and Cognition

2019 ◽  
Vol 31 (9) ◽  
pp. 1271-1289 ◽  
Author(s):  
Holger Dannenberg ◽  
Andrew S. Alexander ◽  
Jennifer C. Robinson ◽  
Michael E. Hasselmo
Keyword(s):  
Episodic Memory ◽  
Verbal Memory ◽  
Memory Function ◽  
Single Agent ◽  
Human Cognition ◽  
Space And Time ◽  
Neurophysiological Data ◽  
Spatio Temporal ◽  
Stimulus Features ◽  
Definition Of

Behavioral research in human verbal memory function led to the initial definition of episodic memory and semantic memory. A complete model of the neural mechanisms of episodic memory must include the capacity to encode and mentally reconstruct everything that humans can recall from their experience. This article proposes new model features necessary to address the complexity of episodic memory encoding and recall in the context of broader cognition and the functional properties of neurons that could contribute to this broader scope of memory. Many episodic memory models represent individual snapshots of the world with a sequence of vectors, but a full model must represent complex functions encoding and retrieving the relations between multiple stimulus features across space and time on multiple hierarchical scales. Episodic memory involves not only the space and time of an agent experiencing events within an episode but also features shown in neurophysiological data such as coding of speed, direction, boundaries, and objects. Episodic memory includes not only a spatio-temporal trajectory of a single agent but also segments of spatio-temporal trajectories for other agents and objects encountered in the environment consistent with data on encoding the position and angle of sensory features of objects and boundaries. We will discuss potential interactions of episodic memory circuits in the hippocampus and entorhinal cortex with distributed neocortical circuits that must represent all features of human cognition.

scholarly journals The effects of acute exercise on episodic memory function among young university students: moderation considerations by biological sex

2019 ◽  
Vol 9 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Lauren Johnson ◽  
Paul D. Loprinzi
Keyword(s):  
Episodic Memory ◽  
University Students ◽  
Verbal Memory ◽  
Acute Exercise ◽  
Memory Function ◽  
Verbal Learning ◽  
Memory Task ◽  
Moderate Intensity ◽  
Term Memory ◽  
Main Effect

Background: The objective of this study was to evaluate potential sex-specific differences on episodic memory function and determine whether sex moderates the effects of acute exercise on episodic memory.Methods: A randomized controlled intervention was employed. This experiment was conducted among young University students (mean age = 21 years). Both males (n=20) and females (n=20)completed two counterbalanced laboratory visits, with one visit involving a 15-minute bout of moderate-intensity exercise prior to the memory task. The control visit engaged in a time matched seated task. Memory function (including short-term memory, learning, and long-term memory) was assessed from the RAVLT (Rey Auditory Verbal Learning Test).Results: We observed a significant main effect for time (P<0.001, ƞ2p= 0.77) and a marginally significant main effect for sex (P=0.06, ƞ2p= 0.09), but no time by sex by condition interaction(P=0.91, ƞ2p= 0.01). We also observed some suggestive evidence of a more beneficial effect of acute exercise on memory for females. Conclusion: In conclusion, females outperformed males in verbal memory function. Additional research is needed to further evaluate whether sex moderates the effects of acute exercise on memory function.

scholarly journals The Self-Fulfilling Prophecy of Episodic Memory Impairment in Mild Cognitive Impairment: Do Episodic Memory Deficits Identified at Classification Remain Evident When Later Examined with Different Memory Tests?

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Shannon Zofia Klekociuk ◽  
Mathew James Summers
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Episodic Memory ◽  
Verbal Memory ◽  
Memory Function ◽  
Memory Deficits ◽  
Memory Tests ◽  
Amnestic Mci ◽  
Screening Assessment ◽  
Multiple Domain

Previous studies of mild cognitive impairment (MCI) have been criticised for using the same battery of neuropsychological tests during classification and longitudinal followup. The key concern is that there is a potential circularity when the same tests are used to identify MCI and then subsequently monitor change in function over time. The aim of the present study was to examine the evidence of this potential circularity problem. The present study assessed the memory function of 72 MCI participants and 50 healthy controls using an alternate battery of visual and verbal episodic memory tests 9 months following initial comprehensive screening assessment and MCI classification. Individuals who were classified as multiple-domain amnestic MCI (a-MCI+) at screening show a significantly reduced performance in visual and verbal memory function at followup using a completely different battery of valid and reliable tests. Consistent with their initial classification, those identified as nonamnestic MCI (na-MCI) or control at screening demonstrated the highest performance across the memory tasks. The results of the present study indicate that persistent memory deficits remain evident in amnestic MCI subgroups using alternate memory tests, suggesting that the concerns regarding potential circularity of logic may be overstated in MCI research.

scholarly journals Lifespan trajectories and relationships to memory of the macro- and microstructure of the anterior and posterior hippocampus – a longitudinal multi-modal imaging study

2019 ◽  
Author(s):  
Espen Langnes ◽  
Markus H. Sneve ◽  
Donatas Sederevicius ◽  
Inge K. Amlien ◽  
Kristine B Walhovd ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Verbal Memory ◽  
Structural Changes ◽  
Diffusion Tensor ◽  
Hippocampal Formation ◽  
Memory Performance ◽  
Memory Function ◽  
Imaging Study ◽  
Future Research ◽  
Microstructural Development

AbstractThere is evidence for a hippocampal long axis anterior-posterior (AP) differentiation in memory processing, which may have implications for the changes in episodic memory performance typically seen across development and aging. The hippocampal formation shows substantial structural changes with age, but the lifespan trajectories of hippocampal sub-regions along the AP axis are not established. The aim of the present study was to test whether the micro- and macro-structural age-trajectories of the anterior (aHC) and posterior (pHC) hippocampus are different. In a single-center longitudinal study, 1790 cognitively healthy participants, 4.1-93.4 years of age, underwent a total of 3367 MRI examinations and 3033 memory tests sessions over 1-6 time points, spanning an interval up to 11.1 years. T1-weighted scans were used to estimate the volume of aHC and pHC, and diffusion tensor imaging to measure mean diffusion (MD) within each region. We found that the macro- and microstructural lifespan-trajectories of aHC and pHC were clearly distinguishable, with partly common and partly unique variance shared with age. aHC showed a protracted period of microstructural development, while pHC microstructural development as indexed by MD was more or less completed in early childhood. In contrast, pHC showed larger unique aging-related changes. A similar aHC – pHC difference was observed for volume, although not as evident as for microstructure. All sub-regions showed age-dependent relationships to episodic memory function. For aHC micro- and macrostructure, the relationships to verbal memory performance varied significantly with age, being stronger among the older participants. Future research should disentangle the relationship between these structural properties and different memory processes – encoding vs. retrieval in particular – across the lifespan.

scholarly journals RE-DEFINING THE SYSTEM BOUNDARIES OF HUMAN-CENTRED DESIGN

2021 ◽  
Vol 1 ◽  
pp. 2521-2530
Author(s):  
Tjark Gall ◽  
Flore Vallet ◽  
Sylvie Douzou ◽  
Bernard Yannou
Keyword(s):  
Urban Mobility ◽  
Design Practice ◽  
System Boundaries ◽  
Space And Time ◽  
Participatory Practices ◽  
Spatio Temporal ◽  
Social Environmental ◽  
Definition Of ◽  
Human Centred Design

AbstractMost services and products are designed in response to the needs, desires or expectations of humans. A variety of methodologies grouped by the term Human-Centred Design (HCD) have been deployed to formalise and improve this process, ranging from user-centred to participatory practices. However, the approaches’ consideration is primarily limited to individuals in their respective space and time.To examine these system boundaries in detail and address potentials for adaptation, this paper reviews dominant HCD methodologies, categorises them and highlights their respective characteristics. Further, concepts and methodologies from related fields are studied for potential contributions to HCD. This results in a proposed re-definition of the system boundaries of HCD by integrating spatio-temporal impacts on humans through an extended social, environmental and economic scope.The different studied approaches and varying impact assessments are exemplarily applied to the case study of urban mobility, in particular human-centred, scenario-based design approaches. However, the described methods and concepts are kept generic to ensure the applicability across various domains of design practice.

scholarly journals Neural basis of episodic memory in the intermediate term after medial temporal lobe resection

2019 ◽  
Vol 131 (3) ◽  
pp. 790-798 ◽  
Author(s):  
Woorim Jeong ◽  
Hyeongrae Lee ◽  
June Sic Kim ◽  
Chun Kee Chung
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe ◽  
Verbal Memory ◽  
Visual Memory ◽  
Medial Temporal Lobe ◽  
Memory Performance ◽  
Memory Function ◽  
Memory Encoding ◽  
Neural Basis ◽  
Surgery Group

OBJECTIVEHow the brain supports intermediate-term preservation of memory in patients who have undergone unilateral medial temporal lobe resection (MTLR) has not yet been demonstrated. To understand the neural basis of episodic memory in the intermediate term after surgery for temporal lobe epilepsy (TLE), the authors investigated the relationship between the activation of the hippocampus (HIP) during successful memory encoding and individual memory capacity in patients who had undergone MTLR. They also compared hippocampal activation with other parameters, including structural volumes of the HIP, duration of illness, and age at seizure onset.METHODSThirty-five adult patients who had undergone unilateral MTLR at least 1 year before recruiting and who had a favorable seizure outcome were enrolled (17 left MTLR, 18 right MTLR; mean follow-up 6.31 ± 2.72 years). All patients underwent a standardized neuropsychological examination of memory function and functional MRI scanning with a memory-encoding paradigm of words and figures. Activations of the HIP during successful memory encoding were calculated and compared with standard neuropsychological memory scores, hippocampal volumes, and other clinical variables.RESULTSGreater activation in the HIP contralateral to the side of the resection was related to higher postoperative memory scores and greater postoperative memory improvement than the preoperative baseline in both patient groups. Specifically, postoperative verbal memory performance was positively correlated with contralateral right hippocampal activation during word encoding in the left-sided surgery group. In contrast, postoperative visual memory performance was positively correlated with contralateral left hippocampal activation during figure encoding in the right-sided surgery group. Activation of the ipsilateral remnant HIP was not correlated with any memory scores or volumes of the HIP; however, it had a negative correlation with the seizure-onset age and positive correlation with the duration of illness in both patient groups.CONCLUSIONSFor the first time, a neural basis that supports effective intermediate-term episodic memory after unilateral MTLR has been characterized. The results provide evidence that engagement of the HIP contralateral rather than ipsilateral to the side of resection is responsible for effective memory function in the intermediate term (> 1 year) after surgery in patients who have undergone left MTLR and right MTLR. Engagement of the material-specific contralesional HIP, verbal memory in the left-sided surgery group, and visual memory in the right-sided surgery group were observed.

scholarly journals An event map of memory space in the hippocampus

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Lorena Deuker ◽  
Jacob LS Bellmund ◽  
Tobias Navarro Schröder ◽  
Christian F Doeller
Keyword(s):  
Episodic Memory ◽  
Large Scale ◽  
De Novo ◽  
Common Mechanism ◽  
Memory Space ◽  
Common Coding ◽  
Space And Time ◽  
Temporal Aspects ◽  
Neural Event ◽  
Spatio Temporal

The hippocampus has long been implicated in both episodic and spatial memory, however these mnemonic functions have been traditionally investigated in separate research strands. Theoretical accounts and rodent data suggest a common mechanism for spatial and episodic memory in the hippocampus by providing an abstract and flexible representation of the external world. Here, we monitor the de novo formation of such a representation of space and time in humans using fMRI. After learning spatio-temporal trajectories in a large-scale virtual city, subject-specific neural similarity in the hippocampus scaled with the remembered proximity of events in space and time. Crucially, the structure of the entire spatio-temporal network was reflected in neural patterns. Our results provide evidence for a common coding mechanism underlying spatial and temporal aspects of episodic memory in the hippocampus and shed new light on its role in interleaving multiple episodes in a neural event map of memory space.

scholarly journals Internal representation of hippocampal neuronal population span a time-distance continuum

2018 ◽  
Author(s):  
Caroline Haimerl ◽  
David Angulo-Garcia ◽  
Vincent Villette ◽  
Susanne. Reichinnek ◽  
Alessandro Torcini ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Temporal Integration ◽  
Critical Role ◽  
Experimental Studies ◽  
Cell Activity ◽  
Network Activity ◽  
Time And Space ◽  
Distance Information ◽  
Space And Time ◽  
Spatio Temporal

AbstractThe hippocampus plays a critical role in episodic memory: the sequential representation of visited places and experienced events. This function is mirrored by hippocampal activity that self organizes into sequences of neuronal activation that integrate spatio-temporal information. What are the underlying mechanisms of such integration is still unknown. Single cell activity was recently shown to combine time and distance information; however, it remains unknown whether a degree of tuning between space and time can be defined at the network level. Here, combining daily calcium imaging of CA1 sequence dynamics in running head-fixed mice and network modeling, we show that CA1 network activity tends to represent a specific combination of space and time at any given moment, and that the degree of tuning can shift within a continuum from one day to the next. Our computational model shows that this shift in tuning can happen under the control of the external drive power. We propose that extrinsic global inputs shape the nature of spatio-temporal integration in the hippocampus at the population level depending on the task at hand, a hypothesis which may guide future experimental studies.Significance StatementThe hippocampus organizes experience in sequences of events that form episodic memory. How are time and space internally computed in the hippocampus in the absence of sequential external inputs? Here we show that time and space are integrated together within the hippocampal network with different degrees of tuning across days. This was found by recording the activity of hundreds of pyramidal cells for several days. We also propose a mechanism supporting such spatio-temporal integration based on a ring attractor network model: the degree of tuning between space and time can be adjusted by modulating the power of a non-sequential external excitatory drive. In this way, the hippocampus is able to generate a spatio-temporal representation tuned to the task at hand.

Impact of Comorbid Depression on Serial Position Effects in Alzheimer’s Disease

GeroPsych ◽  
2014 ◽  
Vol 27 (4) ◽  
pp. 161-169 ◽  
Author(s):  
Nienke A. Hofrichter ◽  
Sandra Dick ◽  
Thomas G. Riemer ◽  
Carsten Schleussner ◽  
Monique Goerke ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Serial Position ◽  
Episodic Memory ◽  
Memory Performance ◽  
Memory Function ◽  
Word List ◽  
Position Effects ◽  
Serial Position Effects ◽  
List Memory

Hippocampal dysfunction and deficits in episodic memory have been reported for both Alzheimer’s disease (AD) and major depressive disorder (MDD). Primacy performance has been associated with hippocampus-dependent episodic memory, while recency may reflect working memory performance. In this study, serial position profiles were examined in a total of 73 patients with MDD, AD, both AD and MDD, and healthy controls (HC) by means of CERAD-NP word list memory. Primacy performance was most impaired in AD with comorbid MDD, followed by AD, MDD, and HC. Recency performance, on the other hand, was comparable across groups. These findings indicate that primacy in AD is impaired in the presence of comorbid MDD, suggesting additive performance decrements in this specific episodic memory function.

Assessment of Memory in Multiple Sclerosis Patients Using the Memory Assessment Scale

1998 ◽  
Vol 86 (3) ◽  
pp. 987-998 ◽  
Author(s):  
Naomi D. Ling ◽  
Michael J. Selby
Keyword(s):  
Multiple Sclerosis ◽  
Verbal Memory ◽  
Memory Function ◽  
Reliability And Validity ◽  
Assessment Scale ◽  
Validity Data ◽  
Nonverbal Memory ◽  
Memory Assessment ◽  
Relapsing Remitting ◽  
Multiple Sclerosis Patients

Previous assessment of memory function In multiple sclerosis patients has yielded mixed findings regarding the type and severity of memory deficits, which may be due to (1) differential selection of scales for memory assessment; (2) limited, inconsistent or weak reliability and validity data for the memory scales employed; (3) poor standardization techniques; (4) lack of theoretical foundation for the measure; and (5) limited control of confounding variables, e.g., education, age and the use of nonverbal memory tests. The purpose of the present study was to assess memory function in multiple sclerosis subjects using the verbal subtests of the Memory Assessment Scale, a relatively new measure designed to overcome many of the aforementioned problems. Participants included 57 patients diagnosed as relapsing-remitting, 47 diagnosed as chronic progressive (two generally recognized types of multiple sclerosis), and 132 contra) participants. A multivariate analysis controlling for age and verbal IQ was significant (Wilks = 5.64, p<.001). One way follow-up tests showed both groups with multiple sclerosis had significantly diminished performance across all memory variables when compared with controls, with the exception of List Clustering Acquisition. This indicated that the patients used clustering (mentally grouping similar words together) as often as controls did. These findings provide support for the presence of significant and consistent verbal memory impairment in multiple sclerosis patients and the particular importance of using psychometrically sound measures in the assessment of this population.

scholarly journals Decline in verbal memory during preclinical Alzheimer's disease: Examination of the effect of APOE genotype

2002 ◽  
Vol 8 (7) ◽  
pp. 943-955 ◽  
Author(s):  
KELLY L. LANGE ◽  
MARK W. BONDI ◽  
DAVID P. SALMON ◽  
DOUGLAS GALASKO ◽  
DEAN C. DELIS ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Older Adults ◽  
Alzheimer's Disease ◽  
Episodic Memory ◽  
Verbal Memory ◽  
Verbal Learning ◽  
Apoe Genotype ◽  
Apoe Ε4 ◽  
Dementia Syndrome ◽  
Ε4 Allele

A subtle decline in episodic memory often occurs prior to the emergence of the full dementia syndrome in nondemented older adults who develop Alzheimer's disease (AD). The APOE-ε4 genotype may engender a more virulent form of AD that hastens this decline. To examine this possibility, we compared the rate of decline in episodic memory during the preclinical phase of AD in individuals with or without at least one APOE ε4 allele. Nondemented normal control (NC; n = 84) participants, nondemented older adults who subsequently developed dementia within 1 or 2 years (i.e., preclinical AD; n = 20), and patients with mild AD (n = 53) were examined with 2 commonly employed tests of episodic memory, the Logical Memory subtest of the Wechsler Memory Scale–Revised and the California Verbal Learning Test. Results revealed a precipitous decline in verbal memory abilities 1 to 2 years prior to the onset of the dementia syndrome, but there was little effect of APOE genotype on the rate of this memory decline. The presence of an APOE-ε4 allele, however, did have a differential effect on the sensitivity of the 2 types of memory tests for tracking progression and made an independent contribution to the prediction of conversion to AD. (JINS, 2002, 8, 943–955.)

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