A new study reveals a possible link between obesity and a lack of neuroplasticity in the brain. I interviewed Dr. Brenton Hordacre about this study conducted by Epi-Centre for Healthy Ageing, IMPACT Institute, School of Medicine, Deakin University.
Who is Dr. Brenton Hordacre?
Dr. Brenton Hordacre is a National Health and Medical Research Council Fellow at the University of South Australia. He leads the Plasticity Theme within IIMPACT and is a registered Physiotherapist. His research is focused on understanding and improving stroke recovery.
He has expertise in non-invasive brain stimulation and neuroimaging to help understand and investigate brain function. Dr. Hordacre has published over 40 peer-reviewed scientific papers.
by Sophia X. Sui, Michael C. Ridding, and Brenton Hordacre
1 Epi-Centre for Healthy Ageing, IMPACT Institute, School of Medicine, Deakin University
2 Innovation, Implementation and Clinical Translation (IIMPACT) in Health, Allied Health and Human Performance, University of South Australia, Adelaide SA 5001, Australia
Obesity is characterised by excessive body fat and is associated with several detrimental health conditions, including cardiovascular disease and diabetes. There is some evidence that people who are obese have structural and functional brain alterations and cognitive deficits. It may be that these neurophysiological and behavioural consequences are underpinned by altered plasticity. This study investigated the relationship between obesity and plasticity of the motor cortex in people who were considered obese (n = 14, nine males, aged 35.4 ± 14.3 years) or healthy weight (n = 16, seven males, aged 26.3 ± 8.5 years). A brain stimulation protocol known as continuous theta burst transcranial magnetic stimulation was applied to the motor cortex to induce a brief suppression of cortical excitability. The suppression of cortical excitability was quantified using single-pulse transcranial magnetic stimulation to record and measure the amplitude of the motor evoked potential in a peripheral hand muscle. Therefore, the magnitude of suppression of the motor evoked potential by continuous theta burst stimulation was used as a measure of the capacity for plasticity of the motor cortex. Our results demonstrate that the healthy-weight group had a significant suppression of cortical excitability following continuous theta burst stimulation (cTBS), but there was no change in excitability for the obese group. Comparing the response to cTBS between groups demonstrated that there was an impaired plasticity response for the obese group when compared to the healthy-weight group. This might suggest that the capacity for plasticity is reduced in people who are obese. Given the importance of plasticity for human behaviour, our results add further emphasis to the potentially detrimental health effects of obesity.