An Exploration of the Own-Age Effect on Facial Emotion Recognition in Normal Elderly People and Individuals with the Preclinical and Demented Alzheimer's Disease

Neural correlates of impaired learning and recognition of novel faces in mild cognitive impairment

OBJECTIVE

Face memory impairment significantly affects social interactions and daily functioning in individuals with mild cognitive impairment (MCI). While deficits in recognizing familiar faces among individuals with MCI have been reported, their ability to learn and recognize unfamiliar faces remains unclear. This study examined the behavioral performance and event-related potentials (ERPs) of unfamiliar face memorization and recognition in MCI.

METHODS

Fifteen individuals with MCI and 15 healthy controls learned and recognized 90 unfamiliar neutral faces. Their performance accuracy and cortical ERPs were compared between the two groups across the learning and recognition phases.

RESULTS

Individuals with MCI had lower accuracy in identifying newly learned faces than healthy controls. Moreover, individuals with MCI had reduced occipitotemporal N170 and central vertex positive potential responses during both the learning and recognition phases, suggesting impaired initial face processing and attentional resources allocation. Also, individuals with MCI had reduced central N200 and frontal P300 responses during the recognition phase, suggesting impaired later-stage face recognition and attention engagement.

CONCLUSION

These findings provide neurobehavioral evidence for impaired learning and recognition of unfamiliar faces in individuals with MCI.

SIGNIFICANCE

Individuals with MCI may have face memory deficits in both early-stage face processing and later-stage recognition .

Emotion Processing Dysfunction in Alzheimer's Disease: An Overview of Behavioral Findings, Systems Neural Correlates, and Underlying Neural Biology

We described behavioral studies to highlight emotional processing deficits in Alzheimer's disease (AD). The findings suggest prominent deficit in recognizing negative emotions, pronounced effect of positive emotion on enhancing memory, and a critical role of cognitive deficits in manifesting emotional processing dysfunction in AD. We reviewed imaging studies to highlight morphometric and functional markers of hippocampal circuit dysfunction in emotional processing deficits. Despite amygdala reactivity to emotional stimuli, hippocampal dysfunction conduces to deficits in emotional memory. Finally, the reviewed studies implicating major neurotransmitter systems in anxiety and depression in AD supported altered cholinergic and noradrenergic signaling in AD emotional disorders. Overall, the studies showed altered emotions early in the course of illness and suggest the need of multimodal imaging for further investigations. Particularly, longitudinal studies with multiple behavioral paradigms translatable between preclinical and clinical models would provide data to elucidate the time course and underlying neurobiology of emotion processing dysfunction in AD.

Research on Emotion Recognition and Dementias: Foundations and Prospects

BACKGROUND

The study of emotion recognition could be crucial for detecting alterations in certain cognitive areas or as an early sign of neurological disorders.

OBJECTIVE

The main objective of the study is to characterize research development on emotion recognition, identifying the intellectual structure that supports this area of knowledge, and the main lines of research attracting investigators' interest.

METHODS

We identified publications on emotion recognition and dementia included in the Web of Science Core Collection, analyzing the scientific output and main disciplines involved in generating knowledge in the area. A co-citation analysis and an analysis of the bibliographic coupling between the retrieved documents elucidated the thematic orientations of the research and the reference works that constitute the foundation for development in the field.

RESULTS

A total of 345 documents, with 24,282 bibliographic references between them, were included. This is an emerging research area, attracting the interest of investigators in Neurosciences, Psychology, Clinical Neurology, and Psychiatry, among other disciplines. Four prominent topic areas were identified, linked to frontotemporal dementia, autism spectrum disorders, Alzheimer's disease, and Parkinson's and Huntington disease. Many recent papers focus on the detection of mild cognitive impairment.

CONCLUSION

Impaired emotion recognition may be a key sign facilitating the diagnosis and early treatment of different neurodegenerative diseases as well as for triggering the necessary provision of social and family support, explaining the growing research interest in this area.