scholarly journals The intrinsic neonatal hippocampal network: rsfMRI findings

2019 ◽  
Author(s):  
Athena L. Howell ◽  
David E. Osher ◽  
Jin Li ◽  
Zeynep M. Saygin
Keyword(s):  
Human Memory ◽  
Memory Systems ◽  
Cortical Networks ◽  
Animal Data ◽  
Human Connectome Project ◽  
Hippocampal Network ◽  
Hippocampal Networks ◽  
Insight Into ◽  
Differential Connectivity ◽  
Anterior Posterior

AbstractMany adults cannot voluntarily recall memories before the ages of 3-5, a phenomenon referred to as “infantile amnesia” The development of the hippocampal network likely plays a significant part in the emergence of the ability to form long-lasting memories. In adults, the hippocampus has specialized and privileged connections with certain cortical networks, which presumably facilitate its involvement in memory encoding, consolidation, and retrieval. Is the hippocampus already specialized in these cortical connections at birth? And are the topographical principles of connectivity (e.g. long-axis specialization) present at birth? We analyzed resting-state hippocampal connectivity in neonates scanned within one week of birth (Developmental Human Connectome Project) and compared them to adults (Human Connectome Project). We explored the connections of the whole hippocampus and its long-axis specialization to seven canonical cortical networks. We found that the neonatal hippocampal networks show clear immaturity at birth: adults showed hippocampal connectivity that was unique for each cortical network, whereas neonates showed no differentiation in hippocampal connectivity across these networks. Further, neonates lacked long-axis specialization (i.e., along anterior-posterior axis) of the hippocampus in its differential connectivity patterns to the cortical networks. This immaturity in connectivity may contribute to immaturity in memory formation in the first years of life.“New and Noteworthy”While animal data, and anatomical and behavioral human data from young children suggest that the hippocampus is immature at birth, to date, there are no direct assessments of human hippocampal functional connectivity (FC) very early in life. Our study explores the FC of the hippocampus to the cortex at birth, allowing insight into the development of human memory systems.

scholarly journals The intrinsic neonatal hippocampal network: rsfMRI findings

2020 ◽  
Vol 124 (5) ◽  
pp. 1458-1468
Author(s):  
Athena L. Howell ◽  
David E. Osher ◽  
Jin Li ◽  
Zeynep M. Saygin
Keyword(s):  
Functional Connectivity ◽  
Human Memory ◽  
Memory Systems ◽  
Human Data ◽  
Animal Data ◽  
Hippocampal Network ◽  
Insight Into

Although both animal data and human data suggest that the hippocampus is immature at birth, to date, there are no direct assessments of human hippocampal functional connectivity (FC) very early in life. Our study explores the FC of the hippocampus to the cortex at birth, allowing insight into the development of human memory systems. In particular, we find that adults and neonates exhibit vastly different hippocampal connectivity profiles—a finding that likely has large developmental implications.

scholarly journals Longitudinal Differences in Human Hippocampal Connectivity During Episodic Memory Processing

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Kyuwan Choi ◽  
Lisa Bagen ◽  
Linley Robinson ◽  
Gray Umbach ◽  
Michael Rugg ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Right Hemisphere ◽  
Human Subjects ◽  
Human Memory ◽  
Memory Systems ◽  
Memory Encoding ◽  
Hemispheric Differences ◽  
Data Set ◽  
Human Hippocampus ◽  
Hippocampal Networks

Abstract The question of longitudinal hippocampal functional specialization is critical to human episodic memory because an accurate understanding of this phenomenon would impact theories of mnemonic function and entail practical consequences for the clinical management of patients undergoing temporal lobe surgery. The implementation of the robotically assisted stereo electroencephalography technique for seizure mapping has provided our group with the opportunity to obtain recordings simultaneously from the anterior and posterior human hippocampus, allowing us to create an unparalleled data set of human subjects with simultaneous anterior and posterior hippocampal recordings along with several cortical regions. Using these data, we address several key questions governing functional hippocampal connectivity in human memory. First, we ask whether functional networks during episodic memory encoding and retrieval are significantly different for the anterior versus posterior hippocampus (PH). We also examine how connections differ across the 2–5 Hz versus 4–9 Hz theta frequency ranges, directly addressing the relative contribution of each of these separate bands in hippocampal–cortical interactions. While we report some overlapping connections, we observe evidence of distinct anterior versus posterior hippocampal networks during memory encoding related to frontal and parietal connectivity as well as hemispheric differences in aggregate connectivity. We frame these findings in light of the proposed AT/PM memory systems. We also observe distinct encoding versus retrieval connectivity patterns between anterior and posterior hippocampal networks, we find that overall connectivity is greater for the PH in the right hemisphere, and further that these networks significantly differ in terms of frontal and parietal connectivity. We place these findings in the context of existing theoretical treatments of human memory systems, especially the proposed AT/PM system. During memory retrieval, we observe significant differences between slow-theta (2–5 Hz) and fast-theta (4–9 Hz) connectivity between the cortex and hippocampus. Taken together, our findings describe mnemonically relevant functional connectivity differences along the longitudinal axis of the human hippocampus that will inform interpretation of models of hippocampal function that seek to integrate rodent and human data.

Human Memory Systems: A Framework for Understanding Dementia

ASHA Leader ◽  
2007 ◽  
Vol 12 (16) ◽  
pp. 8-11 ◽  
Author(s):  
Nidhi Mahendra ◽  
Allegra Apple
Keyword(s):  
Human Memory ◽  
Memory Systems

A Scene-Based Episodic Memory System for a Simulated Autonomous Creature

2013 ◽  
Vol 4 (1) ◽  
pp. 32-64 ◽  
Author(s):  
Elisa C. Castro ◽  
Ricardo R. Gudwin
Keyword(s):  
Episodic Memory ◽  
Navigation System ◽  
Cognitive Architecture ◽  
Human Memory ◽  
Memory Systems ◽  
Memory Module ◽  
The Past ◽  
3D Environment ◽  
Main Ideas

In this paper the authors present the development of a scene-based episodic memory module for the cognitive architecture controlling an autonomous virtual creature, in a simulated 3D environment. The scene-based episodic memory has the role of improving the creature’s navigation system, by evoking the objects to be considered in planning, according to episodic remembrance of earlier scenes testified by the creature where these objects were present in the past. They introduce the main background on human memory systems and episodic memory study, and provide the main ideas behind the experiment.

Factoren Die Het Onthouden Van Vreemdtalige Woorden Beinvloeden

1981 ◽  
Vol 11 ◽  
pp. 227-245
Author(s):  
Caroline Schouten-Van Parreren
Keyword(s):  
Foreign Language ◽  
Recent Literature ◽  
Memory Systems ◽  
Theoretical Background ◽  
Foreign Languages ◽  
New Words ◽  
Psychological Conditions ◽  
Unknown Words ◽  
Insight Into ◽  
Good Retention

In the recent literature on the methodology of foreign language teaching there is a growing consensus that new words should be presented in texts and not in vocabularies. The theoretical background of this assumption is explained through Van Parreren's theory of trace systems in memory. In particular it is argued that a good retention of new words requires that the traces of meaningfully related words be connected in many diffe-rent ways. Words in texts are already so connected (whereas words in vo-cabularies etc. are not). Moreover it is also possible to treat words in texts in a number of different ways. Although it is thus generally acknowledged that presenting words in texts is preferable, little is known about the nature of the psychological processes of comprehending and retaining new words when presented in texts. In order to gain insight into these processes a qualitative investigation was carried out. Texts in different foreign languages were read by adult subjects. These texts contained several words unknown to them. These words were tested twice: after a short and after a longer interval. While recalling the meaning of the words the subjects had to think aloud. These recall protocols were qualitatively analysed with respect to a number of questions. It was concluded that presenting words in texts offer many possibilities to ''embed" words in meaningful memory systems. However some linguistic and psychological conditions (concerning the text and the treatment of the text by the subjects) have to be taken into ac-count. In particular attention has to be paid only to a part of the unknown words, i.e. to the words in linguistically favourable positions. As a fa-vourable psychological condition for comprehension and retention diversity of treatment of the target words by the subjects seems to be required.

Dysfunction of the human memory systems

2003 ◽  
Vol 16 ◽  
pp. S11-S16 ◽  
Author(s):  
Kathy Dujardin ◽  
Bernard Laurent
Keyword(s):  
Human Memory ◽  
Memory Systems

scholarly journals Human memory: insights into hippocampal networks in epilepsy

Brain ◽  
2014 ◽  
Vol 137 (7) ◽  
pp. 1856-1857 ◽  
Author(s):  
Thorsten Bartsch ◽  
Shahar Arzy
Keyword(s):  
Human Memory ◽  
Hippocampal Networks

scholarly journals Bicoid gradient formation mechanism and dynamics revealed by protein lifetime analysis

2018 ◽  
Author(s):  
Lucia Durrieu ◽  
Daniel Kirrmaier ◽  
Tatjana Schneidt ◽  
Ilia Kats ◽  
Sarada Raghavan ◽  
...  
Keyword(s):  
Developmental Biology ◽  
Quantitative Analysis ◽  
Formation Mechanism ◽  
Novel Approach ◽  
Gradient Formation ◽  
Lifetime Analysis ◽  
Abundance And Distribution ◽  
Insight Into ◽  
Anterior Posterior ◽  
Rule Out

AbstractEmbryogenesis relies on instructions provided by spatially organized signaling molecules known as morphogens. Understanding the principles behind morphogen distribution and how cells interpret locally this information remains a major challenge in developmental biology. Here we introduce morphogen-age measurements as a novel approach to retrieve key parameters in morphogen dynamics. Using a tandem fluorescent timer (tFT) as a protein-age sensor we find a gradient of increasing age of Bicoid (Bcd) along the anterior-posterior (AP) axis in the early Drosophila embryo. Quantitative analysis retrieves parameter that are most consistent with the synthesis-diffusion-degradation (SDD) model underlying Bcd-gradient formation, and rule out some other hypotheses for gradient formation. Moreover, we show that the timer can detect transitions in the dynamics associated with syncytial cellularization. Our results provide new insight into Bcd gradient formation, and demonstrate how morphogen age-information can complement knowledge about movement, abundance and distribution, which should be widely applicable for other systems.

scholarly journals Hox genes regulate asexual reproductive behavior and tissue segmentation in adult animals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christopher P. Arnold ◽  
Analí Migueles Lozano ◽  
Frederick G. Mann ◽  
Stephanie H. Nowotarski ◽  
Julianna O. Haug ◽  
...  
Keyword(s):  
Asexual Reproduction ◽  
Hox Genes ◽  
Adult Stage ◽  
Tissue Segmentation ◽  
Hox Gene ◽  
Downstream Effector ◽  
Effector Genes ◽  
And Behavior ◽  
Insight Into ◽  
Anterior Posterior

AbstractHox genes are highly conserved transcription factors renowned for their roles in the segmental patterning of the embryonic anterior-posterior (A/P) axis. We report functions for Hox genes in A/P tissue segmentation and transverse fission behavior underlying asexual reproduction in adult planarian flatworms, Schmidtea mediterranea. Silencing of each of the Hox family members identifies 5 Hox genes required for asexual reproduction. Among these, silencing of hox3 genes results in supernumerary fission segments, while silencing of post2b eliminates segmentation altogether. The opposing roles of hox3 and post2b in segmentation are paralleled in their respective regulation of fission behavior. Silencing of hox3 increases the frequency of fission behavior initiation while silencing of post2b eliminates fission behavior entirely. Furthermore, we identify a network of downstream effector genes mediating Hox gene functions, providing insight into their respective mechanisms of action. In particular, we resolve roles for post2b and effector genes in the functions of the marginal adhesive organ in fission behavior regulation. Collectively, our study establishes adult stage roles for Hox genes in the regulation of tissue segmentation and behavior associated with asexual reproduction.

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