The hippocampus and semantic memory over time

Klooster, Nathaniel; Tranel, Daniel; Duff, Melissa C.

doi:10.1016/j.bandl.2019.104711

Cited by 28 publications

(18 citation statements)

References 48 publications

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“…Thus, acquiring a new semantic representation and maintaining an existing representation are both forms of learning that may place similar demands on the hippocampus. The current study, taken together with Klooster and Duff (2015) and Klooster, Tranel, and Duff et al (2020), suggests that the well-documented deficits in learning new semantic information in amnesia may extend to the learning processes that are involved in maintaining and updating existing, or remote, semantic representations. What is noteworthy here is that a group of patients with hippocampal amnesia who have well documented deficits in new semantic learning of arbitrary relations (Duff et al, 2006;Warren & Duff, 2014) also show disruptions in naming objects, the labels for which they most likely acquired long before the onset of their amnesia.…”

Section: Discussionmentioning

confidence: 58%

“…The strongest version of this view suggests that individuals with hippocampal pathology may experience attrition of semantic and lexical knowledge over time and of knowledge acquired long before the onset of their amnesia. Longitudinal data from patients with hippocampal pathology, or the use of an age of onset comparison group (as was used in Klooster et al, 2020), however, are required to test of this view. Such studies are warranted as they may shed light on the mechanisms of language and knowledge loss in populations like Alzheimer's disease.…”

Section: Discussionmentioning

confidence: 99%

“…What is the mechanism underlying naming disruptions in patients with amnesia and how do these data inform our understanding of the role of hippocampus and declarative memory in semantic memory processing? It is our view that the hippocampal declarative memory system plays a critical role in the acquisition of new semantic memory and in the updating and maintenance of semantic memory representations over time (see Duff et al, 2020; Klooster et al, 2020; Klooster & Duff, 2015). Further, we propose that updating and maintaining semantic representations, the kind of representations necessary to successfully name objects, requires the same hippocampal dependent processes as new semantic learning.…”

Section: Discussionmentioning

confidence: 99%

“…In a follow-up study, Klooster, Tranel, and Duff et al (2020) tested whether the disruption in remote semantic knowledge in patients with amnesia was the result of a failure to update semantic representations since the onset of their amnesia. The authors compared the performance of the same hippocampal patients and their current age (CA) comparisons (M = 58.5 years) (reported in Klooster & Duff, 2015) to a new comparison group matched to the patients' age of onset (AoO) of hippocampal damage (M = 36.8).…”

Section: Introductionmentioning

confidence: 99%

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Evidence of impaired naming in patients with hippocampal amnesia

Hilverman

Duff

2021

Hippocampus

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Object naming involves accessing meaning and retrieving the associated word form from remote semantic memory. Historically, previously acquired semantic knowledge (i.e., remote semantic memory) was thought to be independent of the hippocampus via neocortical consolidation. This view is based on evidence demonstrating a dissociation in behavior in patients with hippocampal amnesia: amnesic patients are impaired in acquiring new vocabulary yet can name and define previously acquired words. More recently, the view that remote semantic memory is hippocampusindependent has been challenged by the documentation of disruptions in aspects of remote semantic memory in patients with hippocampal amnesia, particularly in language use and depth of semantic knowledge. Based on these findings, we hypothesized that the hippocampus plays a long-term role in remote semantic memory. We tested amnesic patients and demographically matched healthy comparison participants in an extensive naming task using photographic images of objects normalized for familiarity, object agreement, and visual complexity. Amnesic patients were less likely to correctly name objects than healthy comparison participants. Further, amnesic patients' performance worsened for words that were less familiar, more visually complex, and had less object agreement. These findings suggest that the hippocampus may play a long-term role in semantic memory processes, rather than a timelimited role in the initial acquisition of semantic information, and that hippocampal damage can disrupt object naming.

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Section: Discussionmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evidence of impaired naming in patients with hippocampal amnesia

Hilverman

Duff

2021

Hippocampus

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“…In addition, as a structure containing the human primary auditory cortex, the right HES is related to the processing of phonological information [ 83 , 84 ]. The bilateral hippocampus is mainly responsible for memory retrieval [ 79 , 85 ]. Therefore, we guessed that, compared with Mandarin MGs, Cantonese-Mandarin BGs were more dependent on the brain network of phonological and semantic processing and memory retrieval.…”

Section: Discussionmentioning

confidence: 99%

The Differences in the Whole-Brain Functional Network between Cantonese-Mandarin Bilinguals and Mandarin Monolinguals

Fan

et al. 2021

Brain Sciences

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Cantonese-Mandarin bilinguals are logographic-logographic bilinguals that provide a unique population for bilingual studies. Whole brain functional connectivity analysis makes up for the deficiencies of previous bilingual studies on the seed-based approach and helps give a complete picture of the brain connectivity profiles of logographic-logographic bilinguals. The current study is to explore the effect of the long-term logographic-logographic bilingual experience on the functional connectivity of the whole-brain network. Thirty Cantonese-Mandarin bilingual and 30 Mandarin monolingual college students were recruited in the study. Resting state functional magnetic resonance imaging (rs-fMRI) was performed to investigate the whole-brain functional connectivity differences by network-based statistics (NBS), and the differences in network efficiency were investigated by graph theory between the two groups (false discovery rate corrected for multiple comparisons, q = 0.05). Compared with the Mandarin monolingual group, Cantonese-Mandarin bilinguals increased functional connectivity between the bilateral frontoparietal and temporal regions and decreased functional connectivity in the bilateral occipital cortex and between the right sensorimotor region and bilateral prefrontal cortex. No significant differences in network efficiency were found between the two groups. Compared with the Mandarin monolinguals, Cantonese-Mandarin bilinguals had no significant discrepancies in network efficiency. However, the Cantonese-Mandarin bilinguals developed a more strongly connected subnetwork related to language control, inhibition, phonological and semantic processing, and memory retrieval, whereas a weaker connected subnetwork related to visual and phonology processing, and speech production also developed.

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