The posterior parietal cortex (PPC) is a cortical region receiving inputs from different
sensory modalities which has been shown to subserve a visuospatial function. The
potential contribution of PPC in audiospatial behaviours and recognition of amodal spatial
correspondences were postulated and assessed in the present study. Adult male Long-
Evans rats received PPC lesions by aspiration, and they were compared to sham operated
control rats on three behavioural tasks. In the Morris water maze, the rats had to learn to
use the distal visual cues to locate an escape platform hidden in the pool. In an open field
task, the rats were assessed on their reactions to a spatial relocation of a visual or an
auditory object. In a spatial cross-modal transfer (CMT) task (Tees & Buhrmann, 1989),
rats were trained to respond to light signals using spatial rules, and were then subjected to
transfer tests using comparable sound signals. Results from the Morris water maze, the
open field, and the initial training phase of the spatial CMT task confirmed a visuospatial
deficit in PPC lesioned rats. However, if given sufficient training, PPC lesioned rats could
learn the location of a hidden platform in the Morris water maze, and they could also
acquire spatial rules in the CMT task. Such results indicated that the visuospatial deficits
in PPC lesioned rats were less severe than previously thought. On the other hand, a
persistent navigational difficulty characterized by a looping pattern of movement was
observed in the PPC lesioned rats in the Morris water maze. Results from the open field
indicated that PPC was less involved in audiospatial behaviours. Moreover, results also
indicated that PPC was not necessary for spatial CMT. Hence, data from the present
study did not support the idea that PPC played an essential role in supramodal spatial
abilities in the rats. Instead, data from the spatial CMT task seemed to imply a role of
PPC in managing conflicting spatial information coming from different sensory modalities.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/5371 |
| Date | 11 1900 |
| Creators | Kwan, Teresa |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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