Occupation-related effects on motor cortex thickness among older, cognitive healthy individuals

Abstract

Both, decline of sensorimotor functions and cortical thickness are known processes in healthy aging. Physical activity has been suggested to enhance the execution of daily routine activities and to extend the time of functional independence in advanced age. We hypothesized that cortical thickness of motor areas in retired individuals could be related to physical demands of the profession carried out during working life. Depending on their former occupations, 69 cognitively healthy individuals (range 70–85 years) were divided into higher and lower physically complex occupations (HPCO n = 27 and LPCO n = 42) according to the international standard classification of occupations (ISCO-08). Participants underwent a high-resolution 3T T1-weighted MRI scan. Surface-based analysis revealed higher cortical thickness in the left precentral (P = 0.001) and postcentral gyrus (P < 0.001) and right postcentral gyrus (P = 0.001) for the HPCO relative to the LPCO group (corrected for multiple comparisons, sex, age and leisure activities in the past 20 years). Physical leisure activities associated with exertion were positively correlated with cortical thickness in the left pre- and postcentral gyrus (P = 0.037) of the LPCO group. Time since retirement was negatively associated with cortical thickness in the left postcentral gyrus (P = 0.004) of the HPCO group. Executing a higher physically complex occupation before retirement was related to relative higher cortical thickness in the primary motor and somatosensory cortex in later life, supporting the hypothesis that physical activity contributes to neural reserve in these regions. However, these benefits appear to vanish when physical activity is reduced due to retirement.

A resting-state functional magnetic resonance imaging study of altered functional brain activity in cardiac arrest survivors with good neurological outcome

“…The precentral and postcentral gyrus are key brain areas for motor and somatosensory functions, respectively ( 24 , 25 ). Atrophy and deficits in the precentral gyrus have been documented in a number of movement-damaged disorders, including amyotrophic lateral sclerosis, stroke, and spinal cord injury, indicating its leading role in controlling body movement ( 26–29 ).…”

Qualitative and Quantitative Comparison of Hippocampal Volumetric Software Applications: Do All Roads Lead to Rome?

“…FS has been additionally applied in our clinic for many years during diagnostic work up of patients with memory deficits. FS and SPM have been extensively used at our center in various studies, and therefore a profound knowledge of these programs is present in our team [ 23 , 24 , 43 , 44 , 45 , 46 ]). Quantib™ was chosen as an example of a commercially available software program and was provided to us during a trial period.…”

“…FS has been additionally applied in our clinic for many years during diagnostic work up of patients with memory deficits, and measurements derived from this method were therefore chosen as inclusion criteria. Based on hippocampal z-scores < −1.96, measured by FS, we retrospectively selected 10 cases and 10 gender- and age-adjusted healthy controls without hippocampal atrophy from a previously published cohort of Alzheimer’s dementia patients and normal ageing controls [ 23 , 24 ]. Z-scores were derived by individually age- and gender-matched control datasets, which were characterized by normal cognitive functions determined by neuropsychological tests and had no history of neurological or psychiatric disorders with an age range of 44 to 85 years.…”

Considering the response in addition to the challenge – a narrative review in appraisal of a motor reserve framework

“…Implicating current concepts in the field of cognitive reserve, the traditional separation of cR as the active (“software”) and brain reserve as the passive (anatomical, “hardware”) part of resilience has gradually been abandoned [ 7 , 39 ]. Since life experiences as well as exercise have been shown to support maintenance of brain integrity and to modulate regional brain volumes [ 40 ], the dichotomy might better be transferred into an integrative view, where brain regions, their projections and synaptic interactions are part of a motor network [ 41 ]. Within this framework, mR would be mirrored in the particular network’s capacity to process information efficiently [ 41 ].…”

“…Therefore, MRI-based morphometry is the method of choice to assess hyper- or hypotrophy of brain regions. For instance, cortical thickness of the motor cortex has been correlated with past physical activity or occupational history [ 40 ], and regional reduction of gray matter volume was associated with measures of physical frailty [ 93 ]. Diffusion tensor imaging (DTI), an estimate of structural connectivity, revealed shorter path length and higher global efficiency of brain networks in high-level basketball players as compared to controls [ 94 ].…”