(1) Animals with medial prefrontal cortex or parietal cortex lesions and sham-operated and non-operated controls were tested for the acquisition of an adjacent arm task that accentuated the importance of egocentric spatial localization and a cheese board task that accentuated the importance of allocentric spatial localization.
(2) This error can be explained on the one hand in terms of response dependence or egocentrism, or on the other hand as due to a lack of adequate spatial cues to allocentric position.
(3) Examples of the presence of properties of ego- and allocentric systems in SMA are given.
(4) A second group of rats was trained on a right-left discrimination (egocentric) and a place-learning task (allocentric).
(5) Both groups were impaired on a spatial landmark test which used luminous stimuli presented in the dark, in positions that varied randomly with respect to the monkey so that only allocentric cues were available.
(6) The data suggest a double dissociation of function between medial prefrontal cortex and parietal cortex in terms of coding of egocentric versus allocentric spatial information.
(7) Three types of neurons were identified by rotating the animals: egocentric and allocentric, and indeterminate.
(8) Of these place related neurons, 21 were also directionally selective with responses described in egocentric or allocentric coordinates or both.
(9) Thus, when an animal is not able to navigate on the basis of an extrapersonal (allocentric) system as a result of drug treatment, it will revert to an egocentric system.
(10) The results indicate that whether an impairment occurs on a task that is thought to test the perception of egocentric space may depend on whether the animal has to notice and attend to a remote cue, and that an attentional disorder may also explain impairments reported on tests of allocentric perception where the critical cue is spatially remote from the response site.
(11) This is in contrast to allocentric localization, where an organism localizes on the basis of cues external to the organism.
(12) The results suggest that these hippocampal neurons may be involved in identification of relations among various kinds of stimuli in different spatial frameworks (egocentric or allocentric) and this identification may be developed from multiple sensory modalities.
(13) The high doses of both CGP compounds as well as dizocilpine produced impairments in the acquisition of an egocentric orientation task and an allocentric reversal task indicated by an increased number of arm entries and re-entries.
(14) The results of this study support the hypothesis that PC plays an important role in the processing of information about space that is allocentric or external to the body.
(15) Two hypotheses have been proposed to account for this goal-invariance property: either (i) the goal is reconstructed and memorized in the stable frame of reference linked to the environment ("allocentric, coordinates") or (ii) the goal is selected and memorized in the sensors-related maps ("egocentric coordinates") and is continuously updated by efferent copies of the motor commands.
(16) Eighty male rats receiving either a unilateral or bilateral lesion of AGm or PPC were examined on an egocentric (adjacent arm) or an allocentric (cheeseboard) maze task.
(17) To test this prediction, two groups of rats were trained on two different egocentric memory tasks and two different allocentric memory tasks.
(18) The results show close relations between the coding of environmental space cues in egocentric and allocentric coordinates, and place related activity in the primate hippocampus.
(19) In contrast, bilateral PPC operates demonstrated a severe deficit in allocentric processing.
(20) Animals were successively trained on navigation in the Morris water maze (allocentric) and delayed spatial alternation in a water T-maze (egocentric).