Biology subjects

Lerner, Y.

Publications and source records attributed to Lerner, Y..

3 recordsLinked to original sources

bioRxiv2021

Physically active lifestyle is associated with attenuation of hippocampal dysfunction in healthy older adults

Alterations in hippocampal function have been shown in older adults, expressed as changes in hippocampal activity and connectivity. While hippocampal activation during memory demands have been demonstrated to decrease with age, some older individuals present increased activity, or hyperactivity, of the hippocampus which is associated with increased neuropathology and poorer memory function. In addition, lower functional coherence between the hippocampus and core hubs of the default mode network (DMN), namely the posteromedial and medial prefrontal cortices, as well as increased local intrahippocampal connectivity, were also demonstrated in cognitively intact older adults. Aerobic exercise has been shown to elicit neuroprotective effects on hippocampal structure and vasculature in aging, and improvements in maximal aerobic capacity (MAC) have been suggested to mediate these exercise-related effects. However, how these lifestyle factors relate to hippocampal function is not clear. Fifty-two cognitively intact older adults (age 65-80) have been recruited and divided into physically active (n=29) or non-active (n=23) groups based on their aerobic activity lifestyle habits. Participants underwent resting-state as well as task-based fMRI experiments which included an associative memory encoding paradigm followed by a post-scan memory recognition test. In addition, forty-four participants also performed cardiopulmonary exercise tests to evaluate MAC. While both groups demonstrated increased anterior hippocampal activation during memory encoding, physically active lifestyle was associated with significantly lower activity level and higher memory performance in the recognition task. In addition, the physically active group also demonstrated higher functional connectivity of the anterior and posterior hippocampi with the core hubs of the DMN, and lower local intra-hippocampal connectivity within and between hemispheres. MAC was negatively associated with hippocampal activation level and demonstrated positive correlation with hippocampal-DMN connectivity. According to these findings, aerobically active lifestyle may be associated with attenuation of hippocampal dysfunction in cognitively healthy older adults.

neuroscience↗

bioRxiv2020

Grey and White Matter Pathways Underlying the Relationship Between Aerobically Active Lifestyle, Cardiorespiratory Function, and Episodic Memory in the Aging Human Brain

Aging is associated with structural alterations of the hippocampus, a key region in episodic memory processes. Aerobic activity and maximal aerobic capacity (MAC), a key measure of cardiorespiratory function and a physiological adaptation of aerobic exercise, have been associated with biological and cognitive resilience of the brain. However, investigations of their relationship with the hippocampus in humans had resulted with inconsistent findings. This study aimed to investigate the relationship between lifestyles aerobic activity and MAC and hippocampal grey and white matter structure, as well as episodic memory performance in cognitively healthy older adults. In addition, we examined the relationship between aerobic activity and MAC, and cerebrovascular pathology expressed as white matter lesions (WML). Next, we used a regression-based mediation analysis to examine possible biological pathways which may underlie the relationship between MAC and hippocampal volume, which was demonstrated in previous works, and was confirmed in the current study. Fifty cognitively healthy older adults (70.92 {+/-} 3.9 years) were divided into aerobically active (n=27) and non-active (n=23) groups, and performed structural and diffusion MRI. Forty-two participants were also evaluated for MAC. Aerobically active lifestyle and higher MAC were associated with increased hippocampal volume and microstructural integrity, as well as increased fornix microstructural integrity, and lower WML burden (p<.05). In addition, both factors were correlated with increased episodic memory performance (p<.05). Mediation analysis revealed two pathways potentially mediating the relationship between MAC, hippocampal volume, and episodic memory - a white matter pathway consisted of WML and fornix microstructure, and grey matter pathway including hippocampal microstructure. These findings shed light on possible neurobiological mechanisms that could potentially underlie the neuroprotective effect of cardiorespiratory function and aerobic physical activity on hippocampal macrostructure and memory function in the aging human brain.

neuroscience↗

bioRxiv2019

Age-Related Changes in Neural Networks Supporting Complex Visual and Social Processing in Adolescence

Despite our differences, there is much about the natural visual world that almost all observers apparently perceive in common. This coherence across observers is evidenced by the finding that, across adults, approximately 30% of the brain is activated in a consistent fashion in response to viewing naturalistic input. The critical question addressed here is how does this consistency emerge and is this pattern of coherence apparent from early in development or does it evolve with time and/or experience? We focused our investigation at a key developmental juncture that might bridge the child and adult patterns, namely, the period of adolescence. We acquired fMRI BOLD data evoked by an 11-minute age-appropriate movie in younger (age 9-14 years) and older adolescents (age 15-19 years) and in adults. Using an intra-subject correlation approach, we characterized the consistency of the neural response within-individual (across two separate runs of the movie), and then, using an inter-subject correlation approach, evaluated the similarity of the response profile within individuals of the same age group and between age-groups. In primary sensory areas (A1+, V1) the response profiles in both groups of adolescents were highly similar to those of the adults, suggesting that these areas are functionally mature at earlier stages of the development. In contrast, some other regions exhibited higher within-age correlations in the adolescent groups than in the adult group. Last, we evaluated the brain responses across the whole cortex and identified the different patterns of maturation as reflected in different inter-subject correlations across the age groups. Together, these findings provide a fine-grained characterization of functional neural development. The approach offers the potential for careful tracking of the development of widespread cortical networks that support the emerging stereotypical responses to naturalistic visual and social stimuli and has important implications for future studies of cortical development.

neuroscience↗