Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Psychology

Faculty/School

Faculty of Science

First Advisor

Philip Servos

Advisor Role

Thesis Supervisor

Abstract

We conducted three block-design experiments using functional magnetic resonance imaging (fMRI) to investigate the cortical areas involved in: 1) processing passively presented pneumatic stimulation, 2) the perception of tactile apparent motion (TAM), and 3) the perception of the cutaneous “rabbit.” In the first experiment (Arm Localizer), periods of random pneumatic stimulation delivered to the ventral right forearm were alternated with periods of rest. The results were consistent with previous research showing activation in the contralateral precentral and postcentral gyri, as well as higher parietal cortical areas. In the second experiment (Apparent Motion), periods of consecutive air puffs presented along the length of the forearm (apparent motion trials) were alternated with periods of random stimulation. The timing of the apparent motion trails was such that participants perceived a broad, continuous, unbroken sweep down the arm. Activation was observed in areas of the limbic occipital, and parietal lobes that are concerned with imagery. In the third experiment (Cutaneous “Rabbit”), periods in which five air puffs were delivered to a location proximal to the elbow, followed by five air puffs to a location proximal to the wrist (cutaneous “rabbit” trials), were alternated with periods of simultaneous air puffs to the same locations. The timing of the cutaneous “rabbit” trials was such that participants perceived a discretely localized train of air puffs between the two actual points of stimulation. Activation was observed primarily in areas of the parietal cortex concerned with tactile attention and the processing of somatosensory information. While it has been known for some time that TAM and the cutaneous “rabbit” are behaviourally distinct, the present study provides the first neuroimaging evidence that TAM and the cutaneous “rabbit” are represented in different areas of the human brain.

Convocation Year

2005

Convocation Season

Spring

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