EEG Brain Oscillations

Animal studies have shown that 40 Hz auditory stimulation alone can improve spatial memory and reduce Aβ deposition. However, human studies using 40 Hz auditory stimulation alone remain limited. Therefore, this study will use a randomized, double-blind, placebo-controlled design to investigate the effects of 40 Hz auditory stimulation on cognitive function, EEG activity, sleep quality, and quality of life in older adults with mild cognitive impairment (MCI) or mild dementia.

The term equilibrium is related to Newton's first law and, as used in mechanics, describes the state where the effect of the forces acting on an object is zero. Equilibrium is divided into two types: static and dynamic. Static equilibrium is the ability to maintain posture without any external forces. This type of equilibrium requires the center of gravity to be kept within the support base. Dynamic equilibrium, on the other hand, is the equilibrium maintained during motion. It requires a controlled shift of the center of gravity. Equilibrium is controlled by the proprioceptive, visual, and vestibular systems. The perception of one's own motion and balance is encoded by proprioceptive and visual signals, along with the vestibular system's perception of inertial motion. Connections between the vestibular nuclei and the cerebellum, hippocampus, prefrontal and parietal cortices provide information for cognitive functions such as spatial functions, navigation, and memory. Adaptation to postural changes in complex environments is known to be achieved through the coordinated and seamless functioning of these structures. In addition to these main systems, spatial orientation has been shown to be a crucial component for balance and posture control. Information from these systems is integrated and processed depending on the task and environment. The interaction and processing of sensory components can also be influenced by ongoing body movements, anticipation, prediction, or instructions. This sensory processing process can depend on many factors. The integration process can also go through a process involving inhibition. For example, standing on the deck of a station, a moving train may cause a person to perceive their own movement. The visual inputs that produce this sensation need to be excluded or blocked from the integration process. Like reweighting, inhibition is a dynamic process. While sensory information continuously flows into the brain, incompatible sensory channel(s) must be identified and blocked from integration. Visual-spatial skills are of great importance for functional independence; they enable us to interact with our environment in 2 and 3 dimensions, perceive the shapes of objects in space, understand the location of objects in space, and understand the spatial orientation of our body. Visual-spatial abilities also include responses to scanning space, reaction speed, visualization, orientation, and sustained or focused attention. Visual stimuli provide individuals with information about the environment. Since visual-spatial codes are three-dimensional, the environment can be perceived in three dimensions. Visual-spatial attention, a component of visual-spatial components, selects relevant sensory information and supports the preparation of responses to this information. It is defined in the Lifelong Development Dictionary published by the APA as 'the way an individual distributes their attention to the visual field'. It selects relevant sensory information and supports the preparation of responses to this information. It allows for selective processing of visual information by prioritizing a specific visual field section. Visual-spatial attention can be directed from one direction to another voluntarily or involuntarily. It is known that cognitive and motor skills develop in a coordinated manner in both children and older adults and that there is a significant relationship between them. There are studies in the literature that address balance and visual-spatial skills and indicate a relationship between them. In their study investigating the relationship between these two functions in stroke patients, Embrechts et al. revealed that reduced visuospatial skills can cause balance and posture problems. It has been suggested that visuospatial input is essential for proactive planning and adjustments to maintain stability in dynamic and complex environments and allows for preventive regulation of movement patterns that provide safe movement and postural control.

Objectives and research hypothesis Physical inactivity is a major health concern that has been linked to a variety of chronic diseases, including obesity, diabetes, cancer, cardiovascular diseases, and mental disorders. Recent studies have shown that regular physical activity can decrease the risk of SARS-CoV-2 infection, and severe COVID-19 illnesses, as well as improve antibody response to vaccine. As such, the adoption of a physically active lifestyle carries potential health benefits and has even been referred to as a "miracle cure" by the Academy of Royal Medical Colleges. Despite the implementation of policies that aimed to encourage regular physical activity, the prevalence of insufficient physical activity in high-income countries has increased since 2001 (32% in 2001 vs. 37% in 2018). Given the limited impact of health policies on physical activity engagement, it is essential to explore other avenues of research that can contribute to understanding this high level of inactivity and driving innovative strategies for encouraging physical activity. In this context, the automatic attraction of individuals toward activities associated with low-effort exertion is thought to play a key role in physical inactivity. Physical activity involves exerting physical effort, i.e., intensifying physical energy to achieve certain goals, such as increasing the force to lift a heavy object. This physical intensification is associated with the phenomenological experience of energy exertion. Higher effort perception is thought to be aversively valued by inactive individuals, inhibiting their engagement in regular physical activity. However, there is a lack of knowledge regarding the neural correlates of effort perception and how they relate to physical inactivity. It is crucial to gain insights into these neural correlates, especially to enhance our comprehension of the significance of effort minimization in physical inactivity. This project aims to decrease effort perception and improve the valuation of effort, incentivize regular physical activity, and improve overall health outcomes. Objective 1. Despite ongoing research, there is a lack of agreement on the neural mechanisms underlying effort perception as well as the role of sensorial feedback. Tasks EEG and fMRI aim to address this issue with original experimental methods in order to identify this neural mechanism. Hypothesis 1. Following A) muscle vibration and B) Induced ischemic paralysis and anesthesia, we expect decreased effort perception associated with a lower cortical S1 activation, unchanged activation in premotor structures, and preserved functional connectivity between premotor regions and S1. Objective 2. To unravel the neural interaction between efference copy and reafferent muscle spindle signals that contribute to effort perception Hypothesis 2. The neural correlates of effort perception involve interactions between premotor and sensory brain structures. Neural activation patterns of the brain regions implicated in effort perception vary depending on an individual's inclination to engage in physical activity. Objective 3. Task 3 will examine the potential of non-invasive brain stimulation techniques (TMS) to reduce effort perception in turn increase its perceived value quantified with the CR100 scale, the outcome variable of this study. Hypothesis 3. Vibration-induced desensitization of muscle spindles and the SMA cTBS reduce effort perception and improve the subjective value of physical effort.

This study aims to evaluate the effects of endogenous gamma non-flickering light stimulation on resting-state EEG rhythms and cognitive function in cognitively healthy older adults. Specifically, it will assess the immediate and long-term effects of this stimulation on brainwave activity and cognitive performance. The study will explore the potential of gamma light stimulation as a non-pharmacological intervention for cognitive decline in aging populations.

In addition to ongoing drug treatments for Alzheimer Disease (AD), protective approaches that can halt the progression of the disease are of particular importance. This project aims to develop a digital application that can monitor cognitive impairment, using EEG findings proven effective at the clinical level in Alzheimer and various types of dementia, including sensory entrainment and digital cognitive games. To this end, a collaboration between Istanbul Medipol University and Güven Future Health Technologies Inc. will develop a device featuring audio-visual sensory entrainment and digital cognitive games. This device will be made available to Alzheimer patients, and the differences between patients who use the application for three months, patients who do not use the application, and healthy controls will be evaluated through neurological examinations, neuropsychological tests, and EEG recordings indicating cognitive functions by the neurologist, project coordinator, and bursars. Monthly assessments, including EEG recordings, will also continue at home, and an application will be created to evaluate changes in cognitive functions through EEG data. By the end of the project, an application that includes sensory entrainment and digital cognitive games, proven effective at the clinical level using EEG findings for Alzheimer dementia patients, will be developed. Additionally, a health kit capable of temporal monitoring of cognitive function changes through EEG data will have been developed.