Abstract
Postural balance is a complex and essential function that enables individuals to maintain stability and interact safely with their environment. It relies on the integration of sensory information from the visual, vestibular, and somatosensory systems, coordinated through central nervous system (CNS) processing.Disruptions in any of these sensory pathways can impact balance control, making it a critical area of study in both clinical and performance contexts. The aim of this study has been to better understand the neural mechanisms that underlie postural control by examining how altered sensory feedback affects brain activity—particularly in the prefrontal cortex (PFC)—and postural sway.
This thesis has investigated how manipulations of visual, vestibular, and somatosensory input have influenced PFC activity and postural sway in healthy younger adults. Functional near-infrared spectroscopy (fNIRS) and inertial measurement units (IMUs) have been used to measure brain activity and balance performance across a range of standing conditions. A dual-task condition involving a working memory load has been introduced only in combination with somatosensory manipulation to examine cognitive-sensory interactions. In addition to traditional statistical analyses, a machine learning–based classification approach has been applied to identify patterns of PFC activation that distinguish between different sensory conditions and levels of postural challenge. This data-driven approach has enabled the identification of cortical features that are most predictive of changes in postural control strategies. The findings have shown that sensory manipulations and dual-task interference have significantly affected postural stability and have led to increased haemodynamic responses in the dorsomedial and dorsolateral PFC. While no significant changes have been observed in overall lateralisation indices, specific dorsolateral PFC channels have demonstrated sensitivity to condition changes. The machine learning analysis has further contributed to understanding the discriminative role of PFC regions in balance regulation under altered sensory input.
This study advances understanding of the PFC role in postural regulation by identifying specific areas involved in balance control under various sensory conditions. Through the integration of fNIRS, IMU data, statistical analysis and machine learning techniques, the study provides novel evidence that distinct PFC regions respond differently to single and dual sensory manipulations with and without a secondary task. It highlights the suitability of oxygenated and deoxygenated haemoglobin for different analytical purposes and establishes a detailed PFC activation map. These findings contribute valuable normative data and identify cortical targets for neurorehabilitation, neuromodulation, and neurofeedback interventions. Moreover, this is the first study to apply multivariate classification to characterise functional contributions of PFC areas to postural control, offering a data-driven foundation for future brain–body interaction research and clinical applications.
| Date of Award | 2025 |
|---|---|
| Original language | English |
| Supervisor | Maryam GHAHRAMANI (Supervisor), Raul Fernandez Rojas (Supervisor) & Roland GOECKE (Supervisor) |