scholarly journals The anterior temporal lobes are critically involved in acquiring new conceptual knowledge: Evidence for impaired feature integration in semantic dementia

Cortex ◽  
2014 ◽  
Vol 50 ◽  
pp. 19-31 ◽  
Author(s):  
Paul Hoffman ◽  
Gemma A.L. Evans ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Conceptual Knowledge ◽  
Semantic Dementia ◽  
Feature Integration ◽  
Temporal Lobes ◽  
Anterior Temporal Lobes

scholarly journals A tale of two hemispheres: Contrasting socioemotional dysfunction in right- versus left-lateralised semantic dementia

2013 ◽  
Vol 7 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Muireann Irish ◽  
Fiona Kumfor ◽  
John R. Hodges ◽  
Olivier Piguet
Keyword(s):  
Conceptual Knowledge ◽  
Semantic Processing ◽  
Empathic Concern ◽  
Semantic Dementia ◽  
Facial Emotions ◽  
Temporal Lobes ◽  
Progressive Degeneration ◽  
Left And Right ◽  
Anterior Temporal Lobes ◽  
The Right

ABSTRACT Objective: Semantic dementia, a subtype of frontotemporal lobar degeneration, is characterised by cross-modal loss of conceptual knowledge attributable to progressive degeneration of the left anterior temporal lobe. Much less is known regarding the clinical presentation of SD patients with predominantly right-lateralised atrophy. Recent reports emphasise marked socioemotional and behavioural disturbances in such cases. Given the importance of the right anterior temporal lobes in social cognition, we hypothesised that socioemotional functioning would be disproportionately affected in right versus left-lateralised SD cases. Methods: We assessed well-characterised cases of predominantly right (n=10) and left (n=12) SD and 20 matched healthy controls on tests of emotion processing and interpersonal functioning. Results: Right SD cases showed disproportionate difficulties in the recognition of positive and negative facial emotions, specifically happiness and anger, compared with left SD cases. Deficits in anger recognition persisted in right SD despite covarying for facial and semantic processing. On a contextually rich task of emotion recognition using multimodal videos, no subgroup differences were evident. Finally, empathic concern was rated as significantly lower by caregivers of right versus left SD cases. Overall, the extent of socioemotional disturbance was associated with the degree of behavioural changes in SD. Conclusion: Our results reveal considerable overlap in the extent to which socioemotional processes are disrupted in left and right-lateralised cases of SD. Notably, however, right SD cases show disproportionate deficits for recognition of facial emotions and the capacity for empathic concern, supporting a specialised role for the right anterior temporal lobes in mediating these cognitive functions.

scholarly journals At the Edge of Semantic Space: The Breakdown of Coherent Concepts in Semantic Dementia Is Constrained by Typicality and Severity but Not Modality

2011 ◽  
Vol 23 (9) ◽  
pp. 2240-2251 ◽  
Author(s):  
Emily J. Mayberry ◽  
Karen Sage ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Conceptual Knowledge ◽  
Information Sources ◽  
Semantic Representation ◽  
Semantic Space ◽  
Semantic Dementia ◽  
Feature Integration ◽  
Specific Information ◽  
Hub And Spoke ◽  
Invariant Representations ◽  
Multiple Modality

Hub-and-spoke models of semantic representation suggest that coherent concepts are formed from the integration of multiple, modality-specific information sources with additional modality-invariant representations—most likely stored in the ventrolateral anterior temporal lobe (vATL). As well as providing the necessary computational mechanisms for the complexities of feature integration, these modality-invariant representations also license a key aspect of semantic memory—semantic-based generalization. Semantic dementia allows us to investigate this aspect of conceptual knowledge because (a) the patients have a selective and progressive semantic degradation and (b) this is associated with profound ventrolateral ATL atrophy. Specifically, the boundaries between concepts become degraded in semantic dementia and, when tested using the appropriate materials, the patients make simultaneous under- and overgeneralization errors. We found that the rate of these errors were a function of typicality and psuedotypicality of the items as well as the severity of the patients' semantic impairment. Following the modality-invariant nature of the vATL hub representation, we also confirmed that the patients were impaired on both verbal- and picture-based versions of the same task.

scholarly journals Differential Activity for Animals and Manipulable Objects in the Anterior Temporal Lobes

2011 ◽  
Vol 23 (8) ◽  
pp. 2059-2067 ◽  
Author(s):  
Stefano Anzellotti ◽  
Bradford Z. Mahon ◽  
Jens Schwarzbach ◽  
Alfonso Caramazza
Keyword(s):  
Conceptual Knowledge ◽  
Bold Signal ◽  
Object Processing ◽  
Susceptibility Artifacts ◽  
Temporal Lobes ◽  
Semantic Categories ◽  
Temporal Pole ◽  
Anterior Temporal Lobes ◽  
The Right ◽  
Neuropsychological Findings

Neuropsychological evidence has highlighted the role of the anterior temporal lobes in the processing of conceptual knowledge. That putative role is only beginning to be investigated with fMRI as methodological advances are able to compensate for well-known susceptibility artifacts that affect the quality of the BOLD signal. In this article, we described differential BOLD activation for pictures of animals and manipulable objects in the anterior temporal lobes, consistent with previous neuropsychological findings. Furthermore, we found that the pattern of BOLD signal in the anterior temporal lobes is qualitatively different from that in the fusiform gyri. The latter regions are activated to different extents but always above baseline by images of the preferred and of the nonpreferred categories, whereas the anterior temporal lobes tend to be activated by images of the preferred category and deactivated (BOLD below baseline) by images of the nonpreferred category. In our experimental design, we also manipulated the decision that participants made over stimuli from the different semantic categories. We found that in the right temporal pole, the BOLD signal shows some evidence of being modulated by the task that participants were asked to perform, whereas BOLD activity in more posterior regions (e.g., the fusiform gyri) is not modulated by the task. These results reconcile the fMRI literature with the neuropsychological findings of deficits for animals after damage to the right temporal pole and suggest that anterior and posterior regions within the temporal lobes involved in object processing perform qualitatively different computations.

scholarly journals The anterior temporal lobes and the functional architecture of semantic memory

2009 ◽  
Vol 15 (5) ◽  
pp. 645-649 ◽  
Author(s):  
W. KYLE SIMMONS ◽  
ALEX MARTIN
Keyword(s):  
Semantic Memory ◽  
Conceptual Knowledge ◽  
Future Research ◽  
Functional Architecture ◽  
Temporal Lobes ◽  
Anterior Temporal Lobes ◽  
General Semantic

AbstractRecently, three accounts have emerged on the role of the anterior temporal lobes (ATLs) in semantic memory. One account claims that the ATLs are domain-general semantic hubs, another claims that they underlie knowledge of unique entities specifically, and yet another account claims that they support social conceptual knowledge generally. Here, we review neuropsychological and neuroimaging studies that bear on these three accounts and offer suggestions for future research to elucidate the roles of the ATLs in semantic memory. (JINS, 2009, 15, 645–649.)

scholarly journals Correlation between Topographic N400 Anomalies and Reduced Cerebral Blood Flow in the Anterior Temporal Lobes of Patients with Dementia

2013 ◽  
Vol 36 (4) ◽  
pp. 711-731 ◽  
Author(s):  
Matthias Grieder ◽  
Raffaella M. Crinelli ◽  
Kay Jann ◽  
Andrea Federspiel ◽  
Miranka Wirth ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Temporal Lobes ◽  
Anterior Temporal Lobes

scholarly journals Graded specialization within and between the anterior temporal lobes

2015 ◽  
Vol 1359 (1) ◽  
pp. 84-97 ◽  
Author(s):  
Grace E. Rice ◽  
Paul Hoffman ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Temporal Lobes ◽  
Anterior Temporal Lobes
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