Considering Hemispheric Specialization in Emotional Face Processing: An Eye Tracking Study in Left- and Right-Lateralised Semantic Dementia.

Face processing relies on a network of occipito-temporal and frontal brain regions. Temporal regions are heavily involved in looking at and processing emotional faces; however, the contribution of each hemisphere to this process remains under debate. Semantic dementia (SD) is a rare neurodegenerative brain condition characterized by anterior temporal lobe atrophy, which is either predominantly left- (left-SD) or right-lateralised (right-SD). This syndrome therefore provides a unique lesion model to understand the role of laterality in emotional face processing. Here, we investigated facial scanning patterns in 10 left-SD and 6 right-SD patients, compared to 22 healthy controls. Eye tracking was recorded via a remote EyeLink 1000 system, while participants passively viewed fearful, happy, and neutral faces over 72 trials. Analyses revealed that right-SD patients had more fixations to the eyes than controls in the Fear (p = 0.04) condition only. Right-SD patients also showed more fixations to the eyes than left-SD patients in all conditions: Fear (p = 0.01), Happy (p = 0.008), and Neutral (p = 0.04). In contrast, no differences between controls and left-SD patients were observed for any emotion. No group differences were observed for fixations to the mouth, or the whole face. This study is the first to examine patterns of facial scanning in left- versus right- SD, demonstrating more of a focus on the eyes in right-SD. Neuroimaging analyses showed that degradation of the right superior temporal sulcus was associated with increased fixations to the eyes. Together these results suggest that right lateralised brain regions of the face processing network are involved in the ability to efficiently utilise changeable cues from the face.

Relational rule discovery in complex discrimination learning.

Failure to learn and generalize abstract relational rules has critical implications for education. In this study, we aimed to determine which training conditions facilitate relational transfer in a relatively simple (patterning) discrimination versus a relatively complex (biconditional) discrimination. The amount of training participants received had little influence on rates of relational transfer. Instead, trial-sequencing of the training contingencies influenced relational transfer in different ways depending on the complexity of the discrimination. Clustering instances of relational rules together during training improved transfer of both simpler patterning and more difficult biconditional rules, regardless of individual differences in cognitive reflection. However, blocking all trials of the same type together improved rule transfer only for biconditional discriminations. Individual differences in cognitive reflection were also more predictive of relational rule use under suboptimal training conditions. The results highlight the need for comprehensive accounts of relational learning to consider how learning conditions and individual differences affect the likelihood of engaging in learning relational structures. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Looking but not seeing: Increased eye fixations in behavioural-variant frontotemporal dementia.

Face processing plays a central role in human communication, with the eye region a particularly important cue for discriminating emotions. Indeed, reduced attention to the eyes has been argued to underlie social deficits in a number of clinical populations. Despite well-established impairments in facial affect recognition in behavioural-variant frontotemporal dementia, whether these patients also have perturbed facial scanning is yet to be investigated. The current study employed eye tracking to record visual scanning of faces in 20 behavioural-variant frontotemporal dementia patients and 21 controls. Remarkably, behavioural-variant frontotemporal dementia patients displayed more fixations to the eyes of emotional faces, compared to controls. Neural regions associated with fixations to the eyes included the left inferior frontal gyrus, right cerebellum and middle temporal gyrus. Our study is the first to show such compensatory functions in behavioural-variant frontotemporal dementia and suggest a feedback-style network, including anterior and posterior brain regions, is involved in early face processing.

Beyond the face: how context modulates emotion processing in frontotemporal dementia subtypes.

The importance of assessing social cognition to characterize dementia syndromes is increasingly recognized, with lower social cognition capacity associated with reduced functional independence and greater carer burden. Emotion recognition is impaired in both behavioural-variant frontotemporal dementia and semantic dementia, yet the social and behavioural changes observed in these syndromes in everyday situations varies. To date, most studies have investigated isolated, context-free stimuli indexing recognition of facial emotions only. Here, we aimed to investigate how contextual information (i.e. emotional body language) influences emotion recognition, within the framework of the Social Context Network Model. Thirty-one patients with frontotemporal dementia (19 behavioural-variant frontotemporal dementia; 12 semantic dementia) and 20 healthy age- and education-matched controls were assessed on three tasks which varied contextual cues: (i) face alone; (ii) context alone; and (iii) face embedded in context. Voxel-based morphometry was used to identify neural correlates of task performance. Our results demonstrated that both behavioural-variant frontotemporal dementia and semantic dementia patients performed worse than controls in recognizing emotions from face alone and context alone. Importantly, performance differed when faces were presented in context. While both behavioural-variant frontotemporal dementia and semantic dementia patients performed similarly to controls on congruent items (i.e. face emotion and body emotion are the same) (P-values > 0.05), patients with behavioural-variant frontotemporal dementia performed worse than both controls (P < 0.001) and patients with semantic dementia (P = 0.044) for incongruent items (i.e. face emotion and body emotion are different). Neuroimaging analyses revealed that abnormal contextual influence was associated with lower integrity of the right parahippocampal gyrus/amygdala and left precentral gyrus. Together, these results indicate that patients with behavioural-variant frontotemporal dementia are over-reliant on external contextual information. Conversely, in semantic dementia and controls, contextual influence varies, with the degree of contextual influence appearing to be mediated, at least in part, by the facial expression depicted. The profile in behavioural-variant frontotemporal dementia is reminiscent of the 'environmental dependency syndrome' described in frontal lesion patients. It also converges with recent evidence of abnormal face perception in this group. From a theoretical perspective, our findings demonstrate that the capacity to incorporate contextual body language is dependent on the integrity of both contextual association brain regions (i.e. parahippocampal gyrus), as well as regions necessary for processing dynamic body movements. Clinically, these results open new avenues for rehabilitation of social impairments in dementia.

Disrupted Face Processing in Frontotemporal Dementia: A Review of the Clinical and Neuroanatomical Evidence.

Faces play an integral role in day-to-day functioning, particularly for social interactions where dynamic and rapid processing of information is vital. Analysis of faces allows an individual to ascertain a wide range of information including deciphering mood and identity, with these assessments directing an individual's subsequent response and behaviours. The prominent social and emotional deficits observed in frontotemporal dementia (FTD), a younger-onset dementia syndrome, may in part reflect a breakdown of the face processing network. Different subtypes of FTD present with divergent patterns of atrophy, although damage is predominantly confined to the frontal and temporal lobes. Specific predictions regarding the role of frontal and temporal regions in face processing have been proposed in the model outlined by Haxby et al. Trends in Cognitive Sciences, 4(6), 223-233 (2000). This model presents a parsimonious method by which to understand face processing in FTD while concurrently allowing assessment of the predictive value and applicability of such a model. By applying the Haxby model to the existing FTD literature, this review presents both direct and indirect evidence of a breakdown in key elements of the face processing network. The type and degree of breakdown appears to differ as a function of FTD subtype and associated brain atrophy. The evidence presented in this review and its relationship with predictions of the Haxby model provides impetus and direction for future research investigating face processing in FTD.

On the right side? A longitudinal study of left- versus right-lateralized semantic dementia.

The typical presentation of semantic dementia is associated with marked, left predominant anterior temporal lobe atrophy and with changes in language. About 30% of individuals, however, present with predominant right anterior temporal lobe atrophy, usually accompanied by behavioural changes and prosopagnosia. Here, we aimed to establish whether these initially distinct clinical presentations evolve into a similar syndrome at the neural and behavioural level. Thirty-one patients who presented with predominant anterior temporal lobe atrophy were included. Based on imaging, patients were categorized as either predominant left (n = 22) or right (n = 9) semantic dementia. Thirty-three Alzheimer's disease patients and 25 healthy controls were included for comparison. Participants completed the Addenbrooke's Cognitive Examination, a Face and Emotion Processing Battery and the Cambridge Behavioural Inventory, and underwent magnetic resonance imaging annually. Longitudinal neuroimaging analyses showed greater right temporal pole atrophy in left semantic dementia than Alzheimer's disease, whereas right semantic dementia showed greater orbitofrontal and left temporal lobe atrophy than Alzheimer's disease. Importantly, direct comparisons between semantic dementia groups revealed that over time, left semantic dementia showed progressive thinning in the right temporal pole, whereas right semantic dementia showed thinning in the orbitofrontal cortex and anterior cingulate. Behaviourally, longitudinal analyses revealed that general cognition declined in all patients. In contrast, patients with left and right semantic dementia showed greater emotion recognition decline than Alzheimer's disease. In addition, left semantic dementia showed greater motivation loss than Alzheimer's disease. Correlational analyses revealed that emotion recognition was associated with right temporal pole, right medial orbitofrontal and right fusiform integrity, while changes in motivation were associated with right temporal pole cortical thinning. While left and right semantic dementia show distinct profiles at presentation, both phenotypes develop deficits in emotion recognition and behaviour. These findings highlight the pervasive socio-emotional deficits in frontotemporal dementia, even in patients with an initial language presentation. These changes reflect right anterior temporal and orbitofrontal cortex degeneration, underscoring the role of these regions in social cognition and behaviour.

Why Should I Care? Dimensions of Socio-Emotional Cognition in Younger-Onset Dementia.

BACKGROUND: Skills such as empathy and emotion recognition rely on a multi-dimensional socio-emotional system. Increasingly, evidence suggests that socio-emotional cognition is affected in frontotemporal dementia and Alzheimer's disease (AD), to varying degrees. However, the specific dimensions of socio-emotional behavior and their neuroanatomical correlates have been relatively unexplored. OBJECTIVE: The current study aimed to: (i) determine how different dimensions of socio-emotional cognition are affected in behavioral-variant frontotemporal dementia (bvFTD), semantic dementia (SD), and AD; (ii) investigate insight into socio-emotional cognition; (iii) identify the neural correlates subserving dimensions of socio-emotional cognition. METHODS: Sixteen bvFTD, 15 SD, 10 AD patients, and 17 controls were included. Each participant and a nominated 'informant' completed the socio-emotional questionnaire; a 30-item rating scale assessing five dimensions of socio-emotional cognition (empathy, emotion recognition, social conformity, antisocial behavior, sociability). RESULTS: SD and bvFTD participants were rated lower on measures of empathy and emotion recognition compared to AD participants and Controls, while other dimensions were relatively intact. In contrast, participants with AD were rated similarly to Controls across all dimensions. SD and bvFTD groups demonstrated reduced insight into socio-emotional dysfunction. Grey matter intensity in the temporal regions correlated with empathy and emotion recognition. Social conformity was associated with the orbitofrontal cortex and amygdala. CONCLUSION: Distinct profiles in typically presenting bvFTD, SD, and AD illustrate preliminary evidence of the utility of socio-emotional cognition in diagnostic clarification. This is an important starting point in understanding socio-emotional functioning in younger-onset dementia, paving the way for targeted management and interventions.

Do I know you? Examining face and object memory in frontotemporal dementia.

The ability to perceive, learn and recognise faces is a complex ability, which is key to successful social interactions. This ability is proposed to be coordinated by neural regions in the occipital and temporal lobes, specialised for face perception and memory. While previous studies have suggested that memory for faces is compromised in some dementia syndromes, it remains unclear whether this simply reflects more generalised memory deficits. Here, we examined basic face perception (Identity-Matching), face recognition (Cambridge Face Memory Task) and object recognition (Cambridge Car Memory Task) in 11 semantic dementia (SD) patients (8 left-lateralised, 3 right-lateralised) and 13 behavioural-variant frontotemporal dementia (bvFTD) patients, compared with 11 controls. On the Identity-Matching task, bvFTD were impaired compared to controls, with a similar trend observed in the SD group. Importantly, both bvFTD and SD also demonstrated impaired face recognition. In contrast, only bvFTD showed impaired object recognition, with SD performing within normal limits on this task. Voxel-based morphometry analyses revealed that Identity-Matching and face recognition were associated with partly dissociable regions including the fusiform cortex and anterior temporal lobe. Object-memory was associated with thalamic integrity in the bvFTD group only. These results reveal that face perception and face memory deficits are common in bvFTD and SD, and have been previously underestimated. These deficits are due to neurodegeneration of key regions within the 'core' and 'extended' face processing system, providing convergent evidence of the neural regions supporting face perception. From a clinical perspective, impaired ability to recognise faces is common in bvFTD and SD and therefore strategies to improve face perception and memory may be beneficial for these patients.