Belief inference for hierarchical hidden states in spatial navigation

Uncertainty abounds in the real world, and in environments with multiple layers of unobservable hidden states, decision-making requires resolving uncertainties based on mutual inference. Focusing on a spatial navigation problem, we develop a Tiger maze task that involved simultaneously inferring the local hidden state and the global hidden state from probabilistically uncertain observation. We adopt a Bayesian computational approach by proposing a hierarchical inference model. Applying this to human task behaviour, alongside functional magnetic resonance brain imaging, allows us to separate the neural correlates associated with reinforcement and reassessment of belief in hidden states. The imaging results also suggest that different layers of uncertainty differentially involve the basal ganglia and dorsomedial prefrontal cortex, and that the regions responsible are organised along the rostral axis of these areas according to the type of inference and the level of abstraction of the hidden state, i.e. higher-order state inference involves more anterior parts

Characteristics of Haptic Peripersonal Spatial Representation of Object Relations

Haptic perception of space is known to show characteristics that are different to actual space. The current study extends on this line of research, investigating whether systematic deviations are also observed in the formation of haptic spatial representations of object-to-object relations. We conducted a haptic spatial reproduction task analogous to the parallelity task with spatial layouts. Three magnets were positioned to form corners of an isosceles triangle and the task of the participant was to reproduce the right angle corner. Weobserved systematic deviations in the reproduction of the right angle triangle. The systematic deviations were not observed when the task was conducted on the mid-sagittal plane. Furthermore, the magnitude of the deviation was decreased when non-informative vision was introduced. These results suggest that there is a deformation in spatial representation of object-to-object relations formed using haptics. However, as no systematic deviation was observed when the task was conducted on the mid-saggital plane, we suggest that the perception of object-to-object relations use a different egocentric reference frame to the perception of orientation

Characteristics of Haptic Peripersonal Spatial Representation of Object Relations.

Haptic perception of space is known to show characteristics that are different to actual space. The current study extends on this line of research, investigating whether systematic deviations are also observed in the formation of haptic spatial representations of object-to-object relations. We conducted a haptic spatial reproduction task analogous to the parallelity task with spatial layouts. Three magnets were positioned to form corners of an isosceles triangle and the task of the participant was to reproduce the right angle corner. Weobserved systematic deviations in the reproduction of the right angle triangle. The systematic deviations were not observed when the task was conducted on the mid-sagittal plane. Furthermore, the magnitude of the deviation was decreased when non-informative vision was introduced. These results suggest that there is a deformation in spatial representation of object-to-object relations formed using haptics. However, as no systematic deviation was observed when the task was conducted on the mid-saggital plane, we suggest that the perception of object-to-object relations use a different egocentric reference frame to the perception of orientation

The frequency of mean trials reproduced in the four areas.

<p>The frequency of mean trials reproduced in the four areas.</p

Mean directional deviations for each axis in the front and upper spaces.

<p>Error bars show <i>SE</i>.</p

Mean directional deviations for each axis in each space for the table hidden group.

<p>Error bars show <i>SE</i>.</p

Scatter diagram of the mean positions of the reproduced magnet for each layout for each participant (crosses).

<p>White circles show the accurate positions of the magnets. 0 shows the position of the participant. a) Left hand group (<i>N</i> = 9) and b) Right hand group (<i>N</i> = 10).</p

Mean directional deviations for each axis in each space for the left hand and right hand.

<p>Error bars show <i>SE</i>.</p

A schematic diagram of the 8 layouts used in the experiment.

<p>For each layout, the right angle corner was the corner which the participant reproduced.</p