Charting the acquisition of semantic knowledge in a case of developmental amnesia

Gardiner, John M.; Brandt, Karen R.; Baddeley, Alan; Vargha‐Khadem, Faraneh; Mishkin, Mortimer

doi:10.1016/j.neuropsychologia.2008.05.021

Cited by 54 publications

(48 citation statements)

References 14 publications

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“…It has been proposed that the learning of semantic associations can bypass the hippocampus entirely and, instead, rely on the ATL (63). Discrete hippocampal damage slows the learning rate of semantic associations but does not impair it completely (64). Indeed, individuals with hippocampal damage can learn new semantic associations through a type of incidental learning called "fast mapping," whereas patients with ATL lesions cannot (65).…”

Section: Discussionmentioning

confidence: 99%

Dynamic neural architecture for social knowledge retrieval

Wang

Collins

Koski

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Social behavior is often shaped by the rich storehouse of biographical information that we hold for other people. In our daily life, we rapidly and flexibly retrieve a host of biographical details about individuals in our social network, which often guide our decisions as we navigate complex social interactions. Even abstract traits associated with an individual, such as their political affiliation, can cue a rich cascade of person-specific knowledge. Here, we asked whether the anterior temporal lobe (ATL) serves as a hub for a distributed neural circuit that represents person knowledge. Fifty participants across two studies learned biographical information about fictitious people in a 2-d training paradigm. On day 3, they retrieved this biographical information while undergoing an fMRI scan. A series of multivariate and connectivity analyses suggest that the ATL stores abstract person identity representations. Moreover, this region coordinates interactions with a distributed network to support the flexible retrieval of person attributes. Together, our results suggest that the ATL is a central hub for representing and retrieving person knowledge.person knowledge | anterior temporal lobe | person identity node | semantic memory | social neuroscience A s social creatures, it is essential that we develop a rich storehouse of knowledge about other members of our social network, such as who they are, how they look and sound, where they live, and what they do for a living. However, little is known about how and where such "person knowledge" is represented, stored, and retrieved in the brain. This inquiry is challenging because person knowledge is highly multimodal and multifaceted, being linked to both abstract features such as personality and social status as well as more concrete features such as eye color; in addition, familiar individuals are associated with detailed episodic and semantic memories (e.g., memories of shared experiences and biographic information) (1, 2). The neural circuit for person knowledge must therefore have the ability to combine multiple sources of information into an abstract representation accessible from multiplicative cues.An influential theory by Burton and Bruce (3) proposes that person recognition is achieved through a hierarchical process that begins with the activation of modality-specific recognition units that selectively respond to the presence of a known face, name, or voice. This information is then sent to an amodal person identity node (PIN) that integrates information from the modality-specific recognition units into a multimodal representation for that individual. Excitation of the PIN ultimately allows the retrieval of personspecific semantic information independently of stimulus modality (4, 5). A similar design is embedded in the "hub-and-spoke" theory of semantic knowledge, which proposes that different features of a concept (such as its color or taste) are distributed throughout the brain (the "spokes") and that a centralized "hub" integrates these features into a cohe...

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Section: Discussionmentioning

confidence: 99%

Dynamic neural architecture for social knowledge retrieval

Wang

Collins

Koski

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Likewise, Vargha-Khadem, Gadian, Watkins, Connelly, Van Paesschen, W., et al (1997) demonstrated that patients with developmental amnesia can show a very good level of semantic knowledge, acquired in childhood and adolescence, despite significant impairment in episodic learning. A more recent study of one of these patients (Jon) showed that he can learn new facts, but that his inter-trial retention was impaired relative to controls (Gardiner, Brandt, Baddeley, Vargha-Khadem, & Mishkin, 2008). In Korsakoff patients, Pitel, Beaunieux, Guillery-Girard, Witkowski, de la Sayette, et al (2009) argued for a 2-route theory of new semantic learning (cf.…”

Section: Introductionmentioning

confidence: 99%

Amnesia in an actor: Learning and re-learning of play passages despite severe autobiographical amnesia

Kopelman

Morton

2015

Cortex

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We describe the case of an accomplished actor, whom we term AB, who suffered severe amnesia following a cardiac arrest and hypoxic brain damage, affecting medial temporal and thalamic structures. His performance on standard episodic memory tests, and on measures of retrograde amnesia, including autobiographical memory, was severely impaired. When presented with passages from plays he had not appeared in, AB showed a severe impairment at the first learning trial, but thereafter showed a 'normal' learning curve for this semantically and syntactically complex material. On being presented with passages from plays he had performed in the past, AB did not show any recognition of them whatsoever, as one might expect from his severe episodic memory impairment. However, AB showed a striking benefit (savings score) in relearning passages he had previously performed, compared with new passages, despite not having any autobiographical recall of having performed the relearned passages before. Moreover, although his initial recall performance in learning these passages was impaired compared with healthy control actors of similar age and experience, AB demonstrated the same incremental learning rate on subsequent learning trials of the passages as did the controls. We conclude that, although severely impaired at the first learning trial (on both 'new' and 'old' passages), AB was able to employ his long-established semantic and procedural skills to attempt the task, and that thereafter he showed a 'normal' rate of incremental learning from a lower baseline.

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“…The resulting, highly structured, information system is termed 'semantic memory' (Patterson et al, 2007;Tulving, 1985) and is thought to depend on networks comprising widespread cortical regions (Binder et al, 2009;Martin and Chao, 2001). Various observations suggest that the formation of semantic memories depends in large part on episodic memory (Moscovitch et al, 2005;Rosenbaum et al, 2001; but see Gardiner et al, 2008 for an opposite viewpoint) and an intact hippocampus (Bayley and Squire, 2005;Hayman et al, 1993;Manns et al, 2003). Episodic memory refers to memory for events and situations, organized in an autobiographical stream, and rich in contextual information (Tulving, 1983).…”

Section: Introductionmentioning

confidence: 99%

Neural mechanisms supporting the extraction of general knowledge across episodic memories

et al. 2014

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a b s t r a c t a r t i c l e i n f oGeneral knowledge acquisition entails the extraction of statistical regularities from the environment. At high levels of complexity, this may involve the extraction, and consolidation, of associative regularities across event memories. The underlying neural mechanisms would likely involve a hippocampo-neocortical dialog, as proposed previously for system-level consolidation. To test these hypotheses, we assessed possible differences in consolidation between associative memories containing cross-episodic regularities and unique associative memories. Subjects learned face-location associations, half of which responded to complex regularities regarding the combination of facial features and locations, whereas the other half did not. Importantly, regularities could only be extracted over hippocampus-encoded, associative aspects of the items. Memory was assessed both immediately after encoding and 48 h later, under fMRI acquisition. Our results suggest that processes related to system-level reorganization occur preferentially for regular associations across episodes. Moreover, the buildup of general knowledge regarding regular associations appears to involve the coordinated activity of the hippocampus and mediofrontal regions. The putative cross-talk between these two regions might support a mechanism for regularity extraction. These findings suggest that the consolidation of cross-episodic regularities may be a key mechanism underlying general knowledge acquisition.

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Charting the acquisition of semantic knowledge in a case of developmental amnesia

Cited by 54 publications

References 14 publications

Dynamic neural architecture for social knowledge retrieval

Dynamic neural architecture for social knowledge retrieval

Amnesia in an actor: Learning and re-learning of play passages despite severe autobiographical amnesia

Neural mechanisms supporting the extraction of general knowledge across episodic memories

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