Hippocampal morphology and cognitive functions in community-dwelling older people: the Lothian Birth Cohort 1936

Abstract

Structural measures of the hippocampus have been linked to a variety of memory processes and also to broader cognitive abilities. Gross volumetry has been widely used, yet the hippocampus has a complex formation, comprising distinct subfields which may be differentially sensitive to the deleterious effects of age, and to different aspects of cognitive performance. However, a comprehensive analysis of multidomain cognitive associations with hippocampal deformations among a large group of cognitively normal older adults is currently lacking. In 654 participants of the Lothian Birth Cohort 1936 (mean age = 72.5, SD = 0.71 years), we examined associations between the morphology of the hippocampus and a variety of memory tests (spatial span, letter-number sequencing, verbal recall, and digit backwards), as well as broader cognitive domains (latent measures of speed, fluid intelligence, and memory). Following correction for age, sex, and vascular risk factors, analysis of memory subtests revealed that only right hippocampal associations in relation to spatial memory survived type 1 error correction in subiculum and in CA1 at the head (β = 0.201, p = 5.843 × 10−4, outward), and in the ventral tail section of CA1 (β = −0.272, p = 1.347 × 10−5, inward). With respect to latent measures of cognitive domains, only deformations associated with processing speed survived type 1 error correction in bilateral subiculum (βabsolute ≤ 0.247, p < 1.369 × 10−4, outward), bilaterally in the ventral tail section of CA1 (βabsolute ≤ 0.242, p < 3.451 × 10−6, inward), and a cluster at the left anterior-to-dorsal region of the head (β = 0.199, p = 5.220 × 10−6, outward). Overall, our results indicate that a complex pattern of both inward and outward hippocampal deformations are associated with better processing speed and spatial memory in older age, suggesting that complex shape-based hippocampal analyses may provide valuable information beyond gross volumetry.

Brain imaging correlates of general intelligence in UK Biobank

“…Likewise, we hypothesised that thalamic and association fibres, plus forceps minor will show the statistically largest associations with general intelligence. The additional use of subcortical volumes was an addition to our preregistered plan; subcortical structure did not figure largely in the P-FIT (Jung & Haier., 2007), though more recent work has reported associations between intelligence and overall subcortical volume (Ritchie et al, 2015), caudate (Basten et al, 2015;Grazioplene et al, 2015;Rhein et al, 2014), hippocampal (Valdés Hernández et al, 2017) and thalamic volume (Bohlken et al, 2014).…”

Lifespan trajectories and relationships to memory of the macro- and microstructure of the anterior and posterior hippocampus – a longitudinal multi-modal imaging study

“…How do aHC and pHC changes relate to episodic memory performance? Volumetric studies have yielded mixed results (Van Petten, 2004), but there are indications in favor of longitudinal compared to cross-sectional relationships (Fjell, McEvoy, et al, 2013; Gorbach et al, 2017; Tamnes et al, 2014), and that correlations may be stronger in certain hippocampal regions (Carr et al, 2017; Daugherty et al, 2017; DeMaster et al, 2014; Hackert et al, 2002; Nordin, Herlitz, Larsson, & Soderlund, 2017; Valdes Hernandez et al, 2017), reflecting specific parts of the memory process (Nadel et al, 2012; Poppenk et al, 2013; Poppenk & Moscovitch, 2011). In addition, relationships may be different in development vs. adulthood and aging (DeMaster et al, 2014).…”

Hierarchical Complexity of the Adult Human Structural Connectome

“…Sex-related inter-hemispheric differences have also been reported 37,38 although a large study presented the idea of a "brain mosaic" of features, some more common in females compared with males and vice versa, after analysing MRI, personality traits, attitudes, interests, and behavioural data from more than 5,500 individuals 38 . In our own experience, for example, hippocampal shape deformations in relation to cognitive functioning exhibit also a high degree of asymmetry 39 . Hierarchical complexity may well provide a link to understand the mechanisms and targeting behind such asymmetric properties.…”