Aerobic exercise increases hippocampal subfield volumes in younger adults and prevents volume decline in the elderly.

Exercise improves both physical and mental health and increases neurogenesis in the dendate gyrus (DG) of the hippocampus. The aim of this study was to examine whether exercising, as compared to no change in regular physical activity, would impact on hippocampal volume, and in particular the core hippocampal structures, DG and cornu ammonis (CA) subfields, and whether any changes would be moderated by age. Thirty nine previously sedentary healthy participants were randomized to either a standardized progressive aerobic exercise program or to "no change" for 16 weeks. Mental health including profile of mood states (POMS), was assessed before and every 4 weeks during the program. Magnetic resonance imaging to examine hippocampal subfields was carried out before and after the program. Aerobic exercise resulted in a significant improvement of the POMS item 'vigour' compared to those in the control group. Overall left hippocampal and left CA4-DG volumes increased significantly in the exercise group while no significant changes were seen in the control group. Older adults in the control group demonstrated significant reductions in CA4-DG subfields over the study, whereas older adults in the exercise group did not show volume decline. These findings reinforce the literature that exercise has a beneficial effect on mental health and can prevent age-related volume decline. Exercise to Improve Resilience, https://register.clinicaltrials.gov/prs/app/action/LoginUser?ts=1&cx=-jg9qo4 , NCT02541136, Rec Ref 2011/45/13.

Longitudinal functional connectivity changes correlate with mood improvement after regular exercise in a dose-dependent fashion.

Exercise increases wellbeing and improves mood. It is however unclear how these mood changes relate to brain function. We conducted a randomized controlled trial investigating resting-state modifications in healthy adults after an extended period of aerobic physical exercise and their relationship with mood improvements. We aimed to identify novel functional networks whose activity could provide a physiological counterpart to the mood-related benefits of exercise. Thirty-eight healthy sedentary volunteers were randomised to either the aerobic exercise group of the study or a control group. Participants in the exercise group attended aerobic sessions with a physiotherapist twice a week for 16 weeks. Resting-state modifications using magnetic resonance imaging were assessed before and after the programme and related to mood changes. An unbiased approach using graph metrics and network-based statistics was adopted. Exercise reduced mood disturbance and improved emotional wellbeing. It also induced a decrease in local efficiency in the parahippocampal lobe through strengthening of the functional connections from this structure to the supramarginal gyrus, precentral area, superior temporal gyrus and temporal pole. Changes in mood disturbance following exercise were correlated with those in connectivity between parahippocampal gyrus and superior temporal gyrus as well as with the amount of training. No changes were detected in the control group. In conclusion, connectivity from the parahippocampal gyrus to motor, sensory integration and mood regulation areas was strengthened through exercise. These functional changes might be related to the benefits of regular physical activity on mood.

Functional connectivity of emotional processing in depression.

OBJECTIVES: The aim of the study is to map a neural network of emotion processing and to identify differences in major depression compared to healthy controls. It is hypothesized that intentional perception of emotional faces activates connections between amygdala (Demir et al.), orbitofrontal cortex (OFC), anterior cingulate cortex (ACC) and prefrontal cortex (PFC) and that frontal-amygdala connections are altered in major depressive disorder (MDD). METHODS: Fifteen medication-free patients with MDD and fifteen healthy controls were enrolled. All subjects were assessed using the same face-matching functional Magnetic Resonance Imaging (fMRI) task, known to involve those areas. Brain activations were obtained using Statistical Parametric Mapping version 5 (SPM5) for data analysis and MARSBAR for extracting of fMRI time series. Then data was analyzed using structural equation modeling (SEM). RESULTS: A valid model was established for the left and the right hemispheres showing a circuit involving ACC, OFC, PFC and AMY. The left hemisphere shows significant lower connectivity strengths in patients than controls, for the pathway that goes from AMY to the OF11, and a trend of higher connectivity in patients for the path that goes from the PF9 to the OF11. In the right hemisphere, patients show lower connectivity coefficients in the paths from the AMY to OF11, from the AMY to ACC, and from the ACC to PF9. By the contrary, controls show lower connectivity strengths for the path that goes from ACC to AMY. CONCLUSIONS: Functional disconnection between limbic and frontal brain regions could be demonstrated using structural equation modeling. The interpretation of these findings could be that there is an emotional processing bias with disconnection bilaterally between amygdala to orbitofrontal cortices and in addition a right disconnection between amygdala and ACC as well as between ACC and prefrontal cortex possibly in line with a more prominent role for the right hemisphere in emotion processing.