fMRI Hippocampal Activity During a VirtualRadial Arm Maze

Abstract

Numerous studies have shown that the hippocampus is critical for spatial memory. Within nonhuman research, a task often used to assess spatial memory is the radial arm maze. Because of the spatial nature of this task, this maze is often used to assess the function of the hippocampus. Our goal was to extrapolate this task to humans and examine whether healthy undergraduates utilize their hippocampus while performing a virtual reality version of the radial arm maze task. Thirteen undergraduates performed a virtual radial arm maze during functional magnetic resonance imaging. The brain maps of activity reveal bilateral hippocampal BOLD signal changes during the performance of this task. However, paradoxically, this BOLD signal change decreases during the spatial memory component of the task. Additionally, we note frontal cortex activity reflective of working memory circuits. These data reveal that, as predicted by the rodent literature, the hippocampus is involved in performing the virtual radial arm maze in humans. Hence, this virtual reality version may be used to assess the integrity of hippocampus so as to predict risk or severity in a variety of psychiatric disorders.

Hippocampal–Dorsolateral Prefrontal Coupling as a Species-Conserved Cognitive Mechanism: A Human Translational Imaging Study

“…Based on these findings, it has been proposed that uncoupling rather than coupling of HC and DLPFC is a signature of successful WM performance (Meyer-Lindenberg et al, 2005). While recruitment of both HC and DLPFC has been reported for imaging studies that examined maze-based navigation (Astur et al, 2005;Iaria et al, 2003;Iglói et al, 2010;Marsh et al, 2010), the role of HC-PFC interactions during maze performance has not been tested previously.…”

Brain Connectivity Related to Working Memory Performance

“…An inverse relationship between activation (as measured via functional imaging) and engagement appears to exist in other parts of the brain. For example, deactivation in the hippocampus (and adjacent regions) has been reported during a transverse patterning task (TPT) and during virtual navigation of a radial arm maze (RAM) (Astur and Constable, 2004;Astur et al, 2005). These task are believed to require engagement of the hippocampus, as the ability to perform TPT or to navigate RAMs is disrupted by hippocampal damage (Olton et al, 1979;Reed and Squire, 1999) (but see Bussey et al, 1998).…”

Common Issues of Virtual Reality in Neuro-Rehabilitation

“…This is supported by studies that training in virtual environment yielded equivalent training effect as training in real environment (Brooks et al, 1999). Moreover, modern functional imaging technology indicated the activation of hippocampus under functional imaging during virtual navigation (Astur et al, 2005). It means that virtual environment or tasks may produce a similar stimulation to corresponding neural structure just like the real environment does.…”