scholarly journals Development and Decline of the Hippocampal Long-Axis Specialization and Differentiation During Encoding and Retrieval of Episodic Memories

2018 ◽  
Vol 29 (8) ◽  
pp. 3398-3414 ◽  
Author(s):  
Espen Langnes ◽  
Didac Vidal-Piñeiro ◽  
Markus H Sneve ◽  
Inge K Amlien ◽  
Kristine B Walhovd ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Life Span ◽  
Task Engagement ◽  
Age Effects ◽  
Associative Memories ◽  
Related Activity ◽  
Younger Adults ◽  
Successful Retrieval ◽  
Development And Aging ◽  
Episodic Memories

Abstract Change in hippocampal function is a major factor in life span development and decline of episodic memory. Evidence indicates a long-axis specialization where anterior hippocampus is more engaged during encoding than during retrieval, and posterior more engaged during retrieval than during encoding. We tested the life span trajectory of hippocampal long-axis episodic memory-related activity and functional connectivity (FC) in 496 participants (6.8–80.8 years) encoding and retrieving associative memories. We found evidence for a long-axis encoding–retrieval specialization that declined linearly during development and aging, eventually vanishing in the older adults. This was mainly driven by age effects on retrieval, which was associated with gradually lower activity from childhood to adulthood, followed by positive age relationships until 70 years. This pattern of age effects characterized task engagement regardless of memory success or failure. Especially for retrieval, children engaged posterior hippocampus more than anterior, while anterior was relatively more activated already in teenagers. Significant intrahippocampal connectivity was found during task, which declined with age. The results suggest that hippocampal long-axis differentiation and communication during episodic memory tasks develop rapidly during childhood, are different in older compared with younger adults, and that the age effects are related to task engagement, not the successful retrieval of episodic memories specifically.

scholarly journals Development and decline of the hippocampal long-axis specialization and differentiation during encoding and retrieval of episodic memories

2018 ◽  
Author(s):  
Espen Langnes ◽  
Didac Vidal-Piñeiro ◽  
Markus H. Sneve ◽  
Inge K. Amlien ◽  
Kristine B Walhovd ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Task Engagement ◽  
Childhood And Adolescence ◽  
Associative Memories ◽  
Hippocampal Function ◽  
Successful Completion ◽  
Related Activity ◽  
Younger Adults ◽  
Development And Aging ◽  
Episodic Memories

AbstractChange in hippocampal function is a major factor in lifespan development and decline of episodic memory. Evidence indicates a long-axis specialization where anterior hippocampus is more engaged during encoding and posterior during retrieval. We tested the lifespan trajectory of hippocampal long-axis episodic memory-related activity and functional connectivity (FC). 496 participants (6.8-80.8 years) were scanned with functional MRI while encoding and retrieving associative memories. We found clear evidence for a long-axis encoding-retrieval specialization. These long-axis effects declined linearly during development and aging, eventually vanishing in the older adults. This was mainly driven by age effects on retrieval. Retrieval was associated with gradually lower activity from childhood to adulthood, followed by positive age-relationships until 70 years. Interestingly, this pattern characterized task engagement regardless of memory success or failure. Children engaged posterior hippocampus more than anterior, while anterior hippocampus was more activated relative to posterior already in teenagers. Intra-hippocampal connectivity increased during task, and this increase declined with age. In sum, the results suggest that hippocampal long-axis differentiation and communication during episodic memory tasks develop rapidly during childhood and adolescence, are markedly different in older compared to younger adults, and are related to task engagement, not the successful completion of the task.

scholarly journals Sensory–perceptual episodic memory and its context: autobiographical memory

2001 ◽  
Vol 356 (1413) ◽  
pp. 1375-1384 ◽  
Author(s):  
Martin A. Conway
Keyword(s):  
Episodic Memory ◽  
Life Span ◽  
Autobiographical Memory ◽  
Knowledge Base ◽  
Recent Experience ◽  
Perceptual Knowledge ◽  
Recollective Experience ◽  
Episodic Memories ◽  
Retention Intervals ◽  
Memory Knowledge

Episodic memory is reconceived as a memory system that retains highly detailed sensory perceptual knowledge of recent experience over retention intervals measured in minutes and hours. Episodic knowledge has yet to be integrated with the autobiographical memory knowledge base and so takes as its context or referent the immediate past of the experiencing self (or the ‘I’). When recalled it can be accessed independently of content and is recollectively experienced. Autobiographical memory, in contrast, retains knowledge over retention intervals measured in weeks, months, years, decades and across the life span. Autobiographical knowledge represents the experienced self (or the ‘me’), is always accessed by its content and, when accessed, does not necessarily give rise to recollective experience. Instead, recollective experience occurs when autobiographical knowledge retains access to associated episodic memories. In this reworking of the ‘episodic memory’ concept autobiographical memory provides the instantiating context for sensory–perceptual episodic memory.

scholarly journals Bi-Temporal Anodal Transcranial Direct Current Stimulation during Slow-Wave Sleep Boosts Slow-Wave Density but Not Memory Consolidation

2021 ◽  
Vol 11 (4) ◽  
pp. 410
Author(s):  
Simon Ruch ◽  
Kristoffer Fehér ◽  
Stephanie Homan ◽  
Yosuke Morishima ◽  
Sarah Maria Mueller ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Slow Wave ◽  
Direct Current ◽  
Memory Consolidation ◽  
Transcranial Direct Current Stimulation ◽  
Slow Wave Sleep ◽  
Memory Performance ◽  
Direct Current Stimulation ◽  
Sleep Parameters ◽  
Episodic Memories

Slow-wave sleep (SWS) has been shown to promote long-term consolidation of episodic memories in hippocampo–neocortical networks. Previous research has aimed to modulate cortical sleep slow-waves and spindles to facilitate episodic memory consolidation. Here, we instead aimed to modulate hippocampal activity during slow-wave sleep using transcranial direct current stimulation in 18 healthy humans. A pair-associate episodic memory task was used to evaluate sleep-dependent memory consolidation with face–occupation stimuli. Pre- and post-nap retrieval was assessed as a measure of memory performance. Anodal stimulation with 2 mA was applied bilaterally over the lateral temporal cortex, motivated by its particularly extensive connections to the hippocampus. The participants slept in a magnetic resonance (MR)-simulator during the recordings to test the feasibility for a future MR-study. We used a sham-controlled, double-blind, counterbalanced randomized, within-subject crossover design. We show that stimulation vs. sham significantly increased slow-wave density and the temporal coupling of fast spindles and slow-waves. While retention of episodic memories across sleep was not affected across the entire sample of participants, it was impaired in participants with below-average pre-sleep memory performance. Hence, bi-temporal anodal direct current stimulation applied during sleep enhanced sleep parameters that are typically involved in memory consolidation, but it failed to improve memory consolidation and even tended to impair consolidation in poor learners. These findings suggest that artificially enhancing memory-related sleep parameters to improve memory consolidation can actually backfire in those participants who are in most need of memory improvement.

scholarly journals Positive Emodiversity Buffers the Association Between Stress and Depressive Symptoms

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 653-653
Author(s):  
Lizbeth Benson ◽  
Anthony Ong
Keyword(s):  
Older Adults ◽  
Depressive Symptoms ◽  
Life Span ◽  
Daily Diary ◽  
National Study ◽  
Younger Adults ◽  
Shannon's Entropy ◽  
Daily Experiences ◽  
Age Related ◽  
Optimal Functioning

Abstract Intensive measurements of individuals’ experiences allow for identifying patterns of functioning that may be markers of resilience, and whether such patterns differ across the life span. Using 8 daily diary reports collected in the second burst of the National Study of Daily Experiences (NSDE, n=848, age 34-84; 55%female), we examined whether positive emodiversity (Shannon’s entropy) attenuated the association between cumulative stressor exposure and depressive symptoms, and age-related differences therein. Results indicated age moderated the extent to which positive emodiversity attenuated the association between stress and depressive symptoms (b=0.11, p < .05). The attenuated association was strongest for younger adults with higher positive emodiversity, compared to those with lower positive emodiversity. For older adults, the association between stress and depressive symptoms was relatively similar regardless of their positive emodiversity. Implications pertain to for whom and in what contexts specific types of dynamic emotion experiences may promote optimal functioning and resilience.

scholarly journals Influence of Dietary Nutrient Intake on Episodic Memory Across the Adult Life Span

2021 ◽  
Vol 13 ◽  
Author(s):  
Selene Cansino ◽  
Frine Torres-Trejo ◽  
Cinthya Estrada-Manilla ◽  
Adriana Flores-Mendoza ◽  
Gerardo Ramírez-Pérez ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Life Span ◽  
Memory Performance ◽  
Life Stage ◽  
Saturated Fatty Acids ◽  
Adult Life ◽  
Middle Aged ◽  
Negative Effects ◽  
Daily Consumption ◽  
Adult Life Span

The aim of the study was to identify nutrients that have the ability to impact brain functioning and, as a consequence, influence episodic memory. In particular, we examined recollection, the ability to recall details of previous experiences, which is the episodic memory process most affected as age advances. A sample of 1,550 healthy participants between 21 and 80 years old participated in the study. Nutritional intake was examined through a food frequency questionnaire and software developed to determine the daily consumption of 64 nutrients based on food intake during the last year. Recollection was measured through a computerized source memory paradigm. First, we identified which nutrients influence recollection across the entire adult life span. Then, moderator analyses were conducted by dividing the sample into young (21–40 years old), middle-aged (41–60 years old) and older (61–80 years old) adults to establish in which life stage nutrients influence episodic memory. Across the adult life span, recollection accuracy was shown to benefit from the intake of sodium, heme, vitamin E, niacin, vitamin B6, cholesterol, alcohol, fat, protein, and palmitic, stearic, palmitoleic, oleic, gadoleic, alpha-linoleic and linoleic acid. The effects of energy, maltose, lactose, calcium and several saturated fatty acids on recollection were modulated by age; in older adults, the consumption of these nutrients negatively influenced episodic memory performance, and in middle-aged adults, only lactose had negative effects. Several brain mechanisms that support episodic memory were influenced by specific nutrients, demonstrating the ability of food to enhance or deteriorate episodic memory.

scholarly journals Autobiographically Significant Concepts: More Episodic than Semantic in Nature? An Electrophysiological Investigation of Overlapping Types of Memory

2015 ◽  
Vol 27 (1) ◽  
pp. 57-72 ◽  
Author(s):  
Louis Renoult ◽  
Patrick S. R. Davidson ◽  
Erika Schmitz ◽  
Lillian Park ◽  
Kenneth Campbell ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Semantic Memory ◽  
Recognition Task ◽  
Positive Component ◽  
Late Positive Component ◽  
Episodic Information ◽  
Semantic Concepts ◽  
N400 Component ◽  
Episodic Memories ◽  
Highly Correlated

A common assertion is that semantic memory emerges from episodic memory, shedding the distinctive contexts associated with episodes over time and/or repeated instances. Some semantic concepts, however, may retain their episodic origins or acquire episodic information during life experiences. The current study examined this hypothesis by investigating the ERP correlates of autobiographically significant (AS) concepts, that is, semantic concepts that are associated with vivid episodic memories. We inferred the contribution of semantic and episodic memory to AS concepts using the amplitudes of the N400 and late positive component, respectively. We compared famous names that easily brought to mind episodic memories (high AS names) against equally famous names that did not bring such recollections to mind (low AS names) on a semantic task (fame judgment) and an episodic task (recognition memory). Compared with low AS names, high AS names were associated with increased amplitude of the late positive component in both tasks. Moreover, in the recognition task, this effect of AS was highly correlated with recognition confidence. In contrast, the N400 component did not differentiate the high versus low AS names but, instead, was related to the amount of general knowledge participants had regarding each name. These results suggest that semantic concepts high in AS, such as famous names, have an episodic component and are associated with similar brain processes to those that are engaged by episodic memory. Studying AS concepts may provide unique insights into how episodic and semantic memory interact.

scholarly journals Mediators of episodic memory decay across the adult life span

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Selene Cansino ◽  
Frine Torres-Trejo ◽  
Cinthya Estrada-Manilla ◽  
Evelia Hernández-Ramos ◽  
Joyce Graciela Martínez-Galindo ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Life Span ◽  
Adult Life ◽  
Adult Life Span ◽  
Memory Decay

scholarly journals Coding of episodic memory in the human hippocampus

2018 ◽  
Vol 115 (5) ◽  
pp. 1093-1098 ◽  
Author(s):  
John T. Wixted ◽  
Stephen D. Goldinger ◽  
Larry R. Squire ◽  
Joel R. Kuhn ◽  
Megan H. Papesh ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Single Neuron ◽  
Large Fraction ◽  
Memory Task ◽  
Neuron Activity ◽  
Distributed Coding ◽  
Repeated Word ◽  
Human Hippocampus ◽  
Left Hippocampus ◽  
Episodic Memories

Neurocomputational models have long posited that episodic memories in the human hippocampus are represented by sparse, stimulus-specific neural codes. A concomitant proposal is that when sparse-distributed neural assemblies become active, they suppress the activity of competing neurons (neural sharpening). We investigated episodic memory coding in the hippocampus and amygdala by measuring single-neuron responses from 20 epilepsy patients (12 female) undergoing intracranial monitoring while they completed a continuous recognition memory task. In the left hippocampus, the distribution of single-neuron activity indicated that only a small fraction of neurons exhibited strong responding to a given repeated word and that each repeated word elicited strong responding in a different small fraction of neurons. This finding reflects sparse distributed coding. The remaining large fraction of neurons exhibited a concurrent reduction in firing rates relative to novel words. The observed pattern accords with longstanding predictions that have previously received scant support from single-cell recordings from human hippocampus.

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