Roles of hippocampal subfields in verbal and visual episodic memory

• Published in: Behavioural brain research Vol. 317; pp. 157 - 162
• Main Authors: Zammit, Andrea R., Ezzati, Ali, Zimmerman, Molly E., Lipton, Richard B., Lipton, Michael L., Katz, Mindy J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.01.2017
• Subjects: Aged; Aged, 80 and over; Aging - psychology; CA1; Cross-Sectional Studies; Cues; Female; Hippocampal subfields; Hippocampus - diagnostic imaging; Hippocampus - physiology; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Memory, Episodic; Mental Recall - physiology; Neuropsychological Tests; Older adults; Oxygen - blood; Photic Stimulation; Residence Characteristics; Statistics as Topic; Subiculum; Verbal episodic memory; Verbal Learning - physiology; Visual episodic memory; Visual episodic memory; Hippocampal subfields; CA1; Subiculum; Verbal episodic memory; Older adults
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2016.09.038

•Neurocognitive tests tapping specific HC subfields can help target at-risk individuals.•Subiculum was associated with verbal and visual episodic memory.•CA1 was associated with verbal and visual episodic memory.•No other subfields were associated with verbal or visual episodic memory.•Our results suggest that CA1 and subiculum are responsible for retrieval. Selective hippocampal (HC) subfield atrophy has been reported in older adults with mild cognitive impairment and Alzheimer’s disease. The goal of this study was to investigate the associations between the volume of hippocampal subfields and visual and verbal episodic memory in cognitively normal older adults. This study was conducted on a subset of 133 participants from the Einstein Aging Study (EAS), a community-based study of non-demented older adults systematically recruited from the Bronx, N.Y. All participants completed comprehensive EAS neuropsychological assessment. Visual episodic memory was assessed using the Complex Figure Delayed Recall subtest from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Verbal episodic memory was assessed using Delayed Recall from the Free and Cued Selective Reminding Test (FCSRT). All participants underwent 3T MRI brain scanning with subsequent automatic measurement of the hemispheric hippocampal subfield volumes (CA1, CA2-CA3, CA4-dente gyrus, presubiculum, and subiculum). We used linear regressions to model the association between hippocampal subfield volumes and visual and verbal episodic memory tests while adjusting for age, sex, education, and total intracranial volume. Participants had a mean age of 78.9 (SD=5.1) and 60.2% were female. Total hippocampal volume was associated with Complex Figure Delayed Recall (β=0.31, p=0.001) and FCSRT Delayed Recall (β=0.27, p=0.007); subiculum volume was associated with Complex Figure Delayed Recall (β=0.27, p=0.002) and FCSRT Delayed Recall (β=0.24, p=0.010); CA1 was associated with Complex Figure Delayed Recall (β=0.26, p<0.002) and FCSRT Delayed Recall (β=0.20, p=0.025). Our findings confirm previous research on the specific roles of CA1 and subiculum in episodic memory. Our results suggest that hippocampal subfields have sensitive roles in the process of visual and verbal episodic memory.