recording brain activity with electroencephalography (eeg) during the virtual spatial navigation task

Game-Based Exploration: Unlocking Human Spatial Navigation Abilities

Moving the body through time and space is critical for learning and remembering information about the environment. This ability is known as spatial navigation, and evolutionarily speaking, it is an essential survival tool for locating food, water, social counterparts, and other rewards in the environment1,2. Spatial navigation is dependent upon the hippocampus, a c-shaped limbic system structure in the medial temporal lobe. The hippocampus consists of the CA1, CA2, CA3, and dentate gyrus subregions. The hippocampus supports the encoding, consolidation, and retrieval of memories that help define the conscious experience. Specifically, spatial navigation supports episodic memory, a form of explicit memory that refers to the memory of personal experience, including aspects of time, place, and relevant details associated with the experience (e.g., sights, sounds, smells, emotions). As we spatially navigate through distinct environments, neurons known as place cells systematically fire, enabling us to understand where we are in both time and space. In fact, direct optical stimulation of these neurons has been shown to bias the behavior of rodents towards their physical location (i.e., place fields)3.
Assessing spatial navigation in rodents has traditionally been studied through such behavioral paradigms as the Morris Water Maze, Y maze, T maze, and radial arm maze4,5. Importantly, these behavioral tasks allow for the in vivo investigation of the neural correlates of spatial navigation using techniques such as electrophysiological depth recordings. However, assessing spatial navigation in humans has proven scientifically challenging because most scientific investigations happen in laboratories and not out in the real world. Previous studies in humans have assessed spatial abilities with traditional paper-based tasks such as bi-directional map learning tasks, mental rotation tasks, or spatial memory tasks6,7. Others have utilized computer-based tasks such as the Virtual Morris Water Task or other virtual maze tasks, which have been shown to be correlated with more traditional psychometric measures of spatial ability8,9. Additionally, with the accessibility of publicly available and free video game software packages, researchers have begun to develop 3-dimensional virtual environments that can either be presented on a computer screen or in virtual reality10,11,12,13,14,15. Scientific advances in mobile brain-body imaging (MoBI) have also allowed researchers to begin to explore spatial navigation in real-world settings16,17,18.
Importantly, spatial learning and memory is a cognitive ability that deteriorates with age, with elderly individuals being more likely to lose track of where they are or become lost when they try to return home. This deficit is most likely due to neurodegeneration that occurs at the level of the hippocampus - a highly plastic brain area that is one of the first to deteriorate with age19. Therefore, developing real-world methods to assess spatial navigational and episodic memory abilities is an important avenue of research. At the clinical level, these types of tasks may help determine the progression of memory decline or diagnose mild cognitive impairment, Alzheimer&#39;s disease, or other forms of dementia. Conversely, physical activity has been identified as one of the best mechanisms to improve spatial navigational abilities. Studies in rodents have shown that exercise enhances learning and memory on various spatial tasks, including the Morris Water Maze, Y maze, T maze, and radial arm maze20. Exercise-induced improvements in spatial abilities have also been demonstrated in humans, with this effect being significantly related to an increase in hippocampal volume7. However, this behavioral effect was demonstrated using a spatial memory task where participants were asked to remember the locations of dots on a screen - a task that may not hold much ecological validity to real-world spatial navigation. Little research has investigated the impact of exercise in humans on spatial navigational tasks presented in virtual environments.
Therefore, a cognitive task was designed to assess spatial learning and memory along with episodic memory using a virtual environment. Importantly, the task was designed using modern-day video game software to enable up-to-date graphic designs and realistic features (e.g., moving clouds in the sky). This task was tested in a group of healthy adults before and after they experienced long-term aerobic exercise practice. Results indicate that participants can encode and remember both spatial information as well as episodic memories regarding their virtual experience. Additionally, findings indicate that performance on this task is plastic, being affected by exercise.
Specifically, a virtual environment was developed through a cross-platform game engine21 that evaluated spatial navigation and episodic memory ability, unique cognitive skills supported by the hippocampus. The map used for this environment was derived from Miller et al. (2013)22. The game engine that was utilized allows developers to download assets to add unique features for the purposes of building virtual environments. An asset23 was utilized that allowed us to build a realistic city environment with roads and buildings through which participants could navigate. Additionally, an asset24 was used that allowed tracking of participants&#39; x, y, and z coordinates and rotation while they traveled through the virtual environment. The aforementioned asset allowed the recording of these features on a millisecond timescale (~33 ms). The virtual environment was then compiled and administered as a spatial navigation task that participants could complete at home on a laptop or desktop computer. The below protocol details how to administer and engage with this spatial navigation task.

Author Spotlight: Investigating the Effects of Mind-Body-Movement Practices on Brain Function

Assessing Human Spatial Navigation in a Virtual Space and its Sensitivity to Exercise

Our research at the Embodied Brain Lab examines the effects of mind-body movement practices like dance, yoga, and meditation on brain function and physiology. And specifically we're looking at the concept of brain plasticity, also known as neuroplasticity, which is really how the body and other things in the environment affect the brain. Our research has shown that exercise and other physical activity practices like dance affect mental health, increasing positive affect, decreasing negative affect, and also enhancing social connection.And we found this at the level of behavior, but we're also looking at how neural activity changes or neural oscillations change in the brain as well.

Recording Brain Activity with Electroencephalography (EEG) During the Virtual Spatial Navigation Task

To begin, use a measuring tape to measure the participant's head from inion to nasion to ensure the proper fitting of the EEG cap. Place electrodes into the EEG cap and outfit the participant with the EEG cap ensuring proper fitting in placement. Now, start the EEG software.Fill each electrode with electrode gel to ensure that impedance measurements are below 25 kiloohms and start the recording. Recruit a member of the research team to watch the participant as the participant performs the spatial task. Send a trigger pulse to the EEG recording system at the start and end of the encoding, remembering an episodic memory phase.

recording-brain-activity-with-electroencephalography-eeg-during

Research

JoVE Journal

Behavior

326 ビュー. まず、測定テープを使用して参加者の頭をイオンからナシオンまで測定し、EEGキャップが適切に取り付けられていることを確認します。電極をEEGキャップに配置し、参加者にEEGキャップを装着して、配置に適切にフィットするようにします。次に、EEGソフトウェアを起動します。各電極に電極ゲルを充填して、インピーダンス測定値が25キロオーム未満であること?...

ビデオ: 仮想空間ナビゲーションタスク中の脳波計(EEG)による脳活動の記録

Spatial navigation (SN) is the ability to locomote through the environment, which requires an understanding of where one is located in time and space. This capacity is known to rely on the sequential firing of place cells within the hippocampus. SN is an important behavior to investigate as this process deteriorates with age, especially in neurodegenerative disorders. However, the investigation of SN is limited by the lack of sophisticated behavioral techniques to assess this hippocampal-dependent task. Therefore, the goal of this protocol was to develop a novel, real-world approach to studying SN in humans. Specifically, an active virtual SN task was developed using a cross-platform game engine. During the encoding phase, participants navigated their way through a virtual city to locate landmarks. During the remembering phase, participants remembered where these reward locations were and delivered items to these locations. Time to find each location was captured and episodic memory was assessed by a free recall phase, including aspects of place, order, item, and association. Movement behavior (x, y, and z coordinates) was assessed through an asset available in the game engine. Importantly, results from this task demonstrate that it accurately captures both spatial learning and memory abilities as well as episodic memory. Further, findings indicate that this task is sensitive to exercise, which improves hippocampal functioning. Overall, the findings suggest a novel way to track human hippocampal functioning over the course of time, with this behavior being sensitive to physical activity training paradigms.

Here, we present a novel, brief, and active spatial navigation task that assesses both spatial navigation and episodic memory ability. Importantly, spatial navigation and episodic memory were associated with one another, and this task demonstrated sensitivity to exercise.

Spatial navigation (SN) is the ability to locomote through the environment, which requires an understanding of where one is located in time and space. ...

Setting Up Gameplay to Perform a Virtual Spatial Navigation Task

Begin by downloading the necessary files for the Unity project. Download Unity Hub from the official website and install Unity version 5.3.1f1. Locate and open the downloaded files as a project within the Unity environment.After creating the project, navigate to the File tab and select the Build and Run option to proceed. Navigate and select Spatial Navigation/scenes/Big City B Lures and Scenes and LaFin. Choose the PC, Mac, and Linux Standalone options.Then click on the Build and Run button. Click the Graphics tab to adjust the screen resolution and the graphics quality. Then move to the Input tab to modify the game's control settings.Afterward, simply click on Play button to begin the spatial navigation task.

Performing a Virtual Spatial Navigation Task to Assess Spatial Learning and Memory

To begin, equip the participant with a mobile electroencephalography device. Ensure the participant is seated comfortably with their feet on the floor. Present on screen instructions, prompting participants to visit landmarks and recall paths in a cityscape.Then instruct the participant to use the mouse in left click to initiate the task. Confirm that the participant comprehends the requirement to navigate the environment using the W, A, S and D keys on their keyboard. Ensure the participant is aware that they can utilize the computer mouse to adjust the subject's point of view simulating head movement.Ask the participant to follow a green path with green arrows to visit the first landmarks. Then instruct the participant to walk through the green diamond at that location. After collecting the green diamond, ask the participant to follow the path to visit the next landmark.Once the participant arrives at the second landmark, instruct them to walk through the green diamond at that location. In the remembering phase, instruct the participant to revisit each landmark. Then, use the mouse and left click on top of Begin.Ask the participant to visit the first landmark that they visited during the encoding phase and deliver a unique item to the first landmark. Once the participant delivers the item, navigate to the second landmark and deliver the next unique item. Instruct the participant to use the mouse to left click on top of begin.Recall the landmarks they visited and the items they delivered in the exact order as instructed earlier in the remembering phase. Instruct the participant to read the final prompt to confirm the completion of the task and the submission of the data. Once the task is completed, locate the results.CSB file in the applications directory. Use the raw data to calculate the appropriate scores, including start time, end time, average seek duration, place score, item score, order score, association score, and episodic memory score. Initial pre-intervention tests revealed an average completion time of 318.69 seconds and an average seek time of 82.88 seconds for the five sites, reflecting spatial navigation ability.Furthermore, participants successfully encoded various aspects of the virtual experience indicative of their episodic memory capacity. Both total time and average seek time, displayed significant correlations with the episodic memory score suggesting a connection between spatial navigation and episodic memory. Preliminary findings showed a significant correlation between age and spatial navigation ability with older age correlating with decreased spatial navigation skills.A significant association was observed between the number of cycling classes, average seek duration, and total seek time.