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Short-term memory maintenance of object locations during active navigation: which working memory subsystem is essential?

Baumann O, Skilleter AJ, Mattingley JB - PLoS ONE (2011)

Bottom Line: We found that while navigation performance in participants with high navigational ability was impaired only by the spatial secondary task, navigation performance in participants with poor navigational ability was impaired equally by spatial and verbal secondary tasks.The visual secondary task had no effect on navigation performance.Our results extend current knowledge by showing that the differential engagement of working memory subsystems is determined by navigational ability.

View Article: PubMed Central - PubMed

Affiliation: Queensland Brain Institute and School of Psychology, The University of Queensland, St Lucia, Queensland, Australia. o.baumann@uq.edu.au

ABSTRACT
The goal of the present study was to examine the extent to which working memory supports the maintenance of object locations during active spatial navigation. Participants were required to navigate a virtual environment and to encode the location of a target object. In the subsequent maintenance period they performed one of three secondary tasks that were designed to selectively load visual, verbal or spatial working memory subsystems. Thereafter participants re-entered the environment and navigated back to the remembered location of the target. We found that while navigation performance in participants with high navigational ability was impaired only by the spatial secondary task, navigation performance in participants with poor navigational ability was impaired equally by spatial and verbal secondary tasks. The visual secondary task had no effect on navigation performance. Our results extend current knowledge by showing that the differential engagement of working memory subsystems is determined by navigational ability.

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Schematic of the virtual environment used in the navigation task.(a) Example display of the virtual environment during the encoding phase of an experimental trial. Landmarks are shown in red, green and blue. The target is shown in yellow, with a virtual light beacon projecting vertically from its apex. (b) Sequence of events in a typical experimental trial. Participants entered the environment and navigated to the target before pressing a button on the joystick to indicate when they reached its location. The encoding phase was followed by a delay period (11 seconds), in which participants were asked simply to remember the object's location (control task), or they were asked to perform one of three secondary tasks (visual, verbal or spatial). In the subsequent retrieval phase, participants re-entered the arena from a different location than in the encoding phase (shifted by 90°, 180° or 270°, with equal probability). They were required to navigate to the location of the target, which was now absent from the display, and to indicate via the joystick when they had arrived there. The next trial commenced after a further delay of 3 seconds.
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pone-0019707-g001: Schematic of the virtual environment used in the navigation task.(a) Example display of the virtual environment during the encoding phase of an experimental trial. Landmarks are shown in red, green and blue. The target is shown in yellow, with a virtual light beacon projecting vertically from its apex. (b) Sequence of events in a typical experimental trial. Participants entered the environment and navigated to the target before pressing a button on the joystick to indicate when they reached its location. The encoding phase was followed by a delay period (11 seconds), in which participants were asked simply to remember the object's location (control task), or they were asked to perform one of three secondary tasks (visual, verbal or spatial). In the subsequent retrieval phase, participants re-entered the arena from a different location than in the encoding phase (shifted by 90°, 180° or 270°, with equal probability). They were required to navigate to the location of the target, which was now absent from the display, and to indicate via the joystick when they had arrived there. The next trial commenced after a further delay of 3 seconds.

Mentions: We used the Blender open source 3D content creation suite (The Blender Foundation, Amsterdam, The Netherlands) to create a virtual environment and administer the navigation task. Participants viewed the environment at a distance of 70 cm from a Dell 2407WFP wide-screen (52 cm ×32 cm) liquid crystal display monitor (Dell Computer Corporation, Austin, TX, USA), and moved through the virtual arena by means of a joystick held in their right hand. The arena consisted of an infinite plain with a pebble-like texture covering the ground to enhance its 3D quality. It contained four visual objects: three landmarks and one target (Figure 1a). The landmarks were cylinders (red, green and blue) with a virtual height of 2.2 meters and a diameter of 1 meter. The target was a yellow pyramid with a virtual height and width of 0.5 meters. The pyramid had a virtual ‘light beacon’, which projected vertically from the apex, to allow its position to be determined when occluded by the landmarks.


Short-term memory maintenance of object locations during active navigation: which working memory subsystem is essential?

Baumann O, Skilleter AJ, Mattingley JB - PLoS ONE (2011)

Schematic of the virtual environment used in the navigation task.(a) Example display of the virtual environment during the encoding phase of an experimental trial. Landmarks are shown in red, green and blue. The target is shown in yellow, with a virtual light beacon projecting vertically from its apex. (b) Sequence of events in a typical experimental trial. Participants entered the environment and navigated to the target before pressing a button on the joystick to indicate when they reached its location. The encoding phase was followed by a delay period (11 seconds), in which participants were asked simply to remember the object's location (control task), or they were asked to perform one of three secondary tasks (visual, verbal or spatial). In the subsequent retrieval phase, participants re-entered the arena from a different location than in the encoding phase (shifted by 90°, 180° or 270°, with equal probability). They were required to navigate to the location of the target, which was now absent from the display, and to indicate via the joystick when they had arrived there. The next trial commenced after a further delay of 3 seconds.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3101206&req=5

pone-0019707-g001: Schematic of the virtual environment used in the navigation task.(a) Example display of the virtual environment during the encoding phase of an experimental trial. Landmarks are shown in red, green and blue. The target is shown in yellow, with a virtual light beacon projecting vertically from its apex. (b) Sequence of events in a typical experimental trial. Participants entered the environment and navigated to the target before pressing a button on the joystick to indicate when they reached its location. The encoding phase was followed by a delay period (11 seconds), in which participants were asked simply to remember the object's location (control task), or they were asked to perform one of three secondary tasks (visual, verbal or spatial). In the subsequent retrieval phase, participants re-entered the arena from a different location than in the encoding phase (shifted by 90°, 180° or 270°, with equal probability). They were required to navigate to the location of the target, which was now absent from the display, and to indicate via the joystick when they had arrived there. The next trial commenced after a further delay of 3 seconds.
Mentions: We used the Blender open source 3D content creation suite (The Blender Foundation, Amsterdam, The Netherlands) to create a virtual environment and administer the navigation task. Participants viewed the environment at a distance of 70 cm from a Dell 2407WFP wide-screen (52 cm ×32 cm) liquid crystal display monitor (Dell Computer Corporation, Austin, TX, USA), and moved through the virtual arena by means of a joystick held in their right hand. The arena consisted of an infinite plain with a pebble-like texture covering the ground to enhance its 3D quality. It contained four visual objects: three landmarks and one target (Figure 1a). The landmarks were cylinders (red, green and blue) with a virtual height of 2.2 meters and a diameter of 1 meter. The target was a yellow pyramid with a virtual height and width of 0.5 meters. The pyramid had a virtual ‘light beacon’, which projected vertically from the apex, to allow its position to be determined when occluded by the landmarks.

Bottom Line: We found that while navigation performance in participants with high navigational ability was impaired only by the spatial secondary task, navigation performance in participants with poor navigational ability was impaired equally by spatial and verbal secondary tasks.The visual secondary task had no effect on navigation performance.Our results extend current knowledge by showing that the differential engagement of working memory subsystems is determined by navigational ability.

View Article: PubMed Central - PubMed

Affiliation: Queensland Brain Institute and School of Psychology, The University of Queensland, St Lucia, Queensland, Australia. o.baumann@uq.edu.au

ABSTRACT
The goal of the present study was to examine the extent to which working memory supports the maintenance of object locations during active spatial navigation. Participants were required to navigate a virtual environment and to encode the location of a target object. In the subsequent maintenance period they performed one of three secondary tasks that were designed to selectively load visual, verbal or spatial working memory subsystems. Thereafter participants re-entered the environment and navigated back to the remembered location of the target. We found that while navigation performance in participants with high navigational ability was impaired only by the spatial secondary task, navigation performance in participants with poor navigational ability was impaired equally by spatial and verbal secondary tasks. The visual secondary task had no effect on navigation performance. Our results extend current knowledge by showing that the differential engagement of working memory subsystems is determined by navigational ability.

Show MeSH