Psychiatric disorders and cognitive impairment are increasingly being described in patients with vestibular pathology. Yet frameworks that describe the link between emotion, memory and the vestibular system have yet to reach maturity, partly because studies have not yet provided detailed accounts of behavioral changes in experimental animals, or in man. One of the goals of this thesis was to use experimental psychology to define changes in memory and emotional behaviour in rats given bilateral vestibular deafferentation (BVD, n=18) or sham surgery (Sham, n=17). In an elevated-plus maze task, BVD rats made up to 166% greater open arm entries and spent up to 42% more time in the open arms compared to Sham rats. In an elevated-T maze task, BVD rats failed to develop a normal learned inhibition response to open space. In an open field maze BVD rats consistently showed 50-60% greater movement velocity, spent on average 35% more time in the inner most aversive part of the arena, and failed to show the normal boundary-seeking behaviour (thigmotaxis) typical of untreated or Sham rats. In a social interaction test BVD rats spent up to 34% less time engaged in social contact compared to Sham rats. In a hyponeophagia test, BVD rats� latency to eat was 70% greater than Sham rats at 3-weeks post-op., however this difference disappeared at 3- and 5-months. These findings suggest that BVD treatment may in some cases disrupt normal behavioral inhibition. Memory performance was also affected. In a T-maze task BVD rats achieved 40-60% correct arm entries, compared to 90-100% for Sham controls. In a foraging task carried out in darkness, BVD rats� initial homing angle was random, homing paths were ~70% longer, and reference memory errors were ~56% greater compared to Sham rats. To elucidate possible neurochemical substrates for these behavioral changes, western blot assays on monoamine proteins were carried out on tissue from a naïve set of rats (BVD n=6; Sham n=6). In BVD rats, serotonin transporter protein expression was 39% lower in CA1 hippocampus and 27% lower in the forebrain region, despite forebrain tryptophan hydroxylase expression being 34% upregulated. Tyrosine hydroxylase expression in the forebrain region was 27% lower in BVD rats. Proteins related to synaptogenesis were also investigated. In the dentate gyrus SNAP-25 was 37% upregulated in BVD rats, while in area CA2/3 of the hippocampus neurofilament-L was 13% upregulated. Forebrain and entorhinal cortex drebrin expression was 28% and 38% downregulated in BVD rats. Neurofilament-L was also 31% downregulated in the forebrain region of BVD rats. To test whether any of these behavioral or biochemical changes may have been attributable to chronic physiological stress, a corticosterone assay was carried out at the conclusion of behavioral testing; however, the no significant between treatment differences were found. In conclusion, vestibular information appears to be needed for the acquisition of spatial and reference memory as well as the normal expression of emotional behaviour. The neurochemical changes described herein point toward possible substrates for these behaviors, however their full significance has yet to be determined.

Thesis (PhD) - Swinburne University of Technology, School of Biophysical Sciences and Electrical Engineering, 2004. / A thesis submitted for the degree of Doctor of Philosophy, School of Biophysical Sciences and Electrical Engineering, Swinburne University of Technology - 2004. Typescript. Includes bibliographical references (p. 259-287).

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The principal aim of this thesis was to test the conjecture of Schacter et al. (1995) that the false memory effect in the Deese-Roediger-McDermott (DRM) paradigm is generated by errors in source monitoring and is mediated by frontal lobe circuits. In support of their conjecture, Schacter et al. cited evidence from elderly populations with presumed frontal dysfunction, however this thesis studied children over an age range over which the frontal lobes are believed to be maturing. This thesis represents the first attempt to specifically test Schacter�s hypothesis based on the developmental trajectory of �frontal� functioning. Moreover, the use of a developmental trajectory in such a manner is relatively novel, and a key issue within this thesis is how to operationalise �frontal� functioning in the sense intended by Schacter et al. Extrapolating from Schacter�s conjecture, it was predicted that the strength of the false memory effect is directly proportional to the degree of frontal maturation, as estimated by both chronological age and by performance on a range of neuropsychological tests of �frontal� executive functioning. False memory and executive functioning were compared in children aged 8 to 12 years and in adults using a modified DRM paradigm with a source monitoring extension after Payne et al. (1996). The modified DRM elicited false memory effects comparable to those reported in adolescents by Newstead and Newstead (1998) and in adults by Roediger and McDermott (1995) and by Payne et al. (1996). Three experiments that demonstrate a strong developmental trajectory for false memory effect are reported, but the pattern of results is not consistent with all of the premises of the conjecture. Although false recognition rates increased significantly with age, source monitoring accuracy did not change across the age groups. Consistent with the principal assertion of the conjecture by Schacter et al., age and a general �frontal� factor were found to be significantly related to the size of the false memory effect. In addition, veridical memory performance was always a predictor of false memory performance. The IAR (Underwood, 1965) theory can best account for the significant covariation between veridical and false memory development, as well as being able to account for the dissociation between false memory and source monitoring.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 131-154).

Whereas some researchers claim that the holistic processing of the right hemisphere is essential for contextual integration in language pragmatics (Myers, 2001, Myers, 2005), results of other studies point to involvement of executive processes of the frontal lobes (McDonald & Pearce, 1998; Bernicot & Dardier, 2001). This study examined the role of frontal lobes in language pragmatics by testing performance of young adults and older adults on selected standardized pragmatic inferences called 'implicitures'. Implicitures were first presented free-standing and then embedded in contexts that either supported (enabling contexts) or cancelled (cancelling contexts) their preferred meaning. First, implicitures were examined using behavioral reaction time measures in young adults. The second part of the project addressed the question about involvement of frontal lobes in language pragmatics by testing older adults with varying degrees of frontal function on processing of implicitures. Finally, event-related potential responses to implicitures with and without context in young adults were explored. Results revealed a strong relationship between frontal lobes and performance on implicitures in canceling contexts in older adults. There was no significant effect for free-standing implicitures and implicitures presented in enabling contexts. In addition, an N400 was observed to free-standing implicitures, but implicitures in context elicited a negative component in the later 400 ms window at the anterior sites. These results indicate that frontal lobes are important for pragmatic processing requiring integration of linguistic context with an utterance for the correct interpretation. Consequences of our findings for models of impliciture processing and accounts of neural architecture underlying language pragmatics are considered.

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Memory for visual patterns was examined in 131 patients with unilateral temporal- or frontal-lobe excisions and 32 normal control subjects. A deficit in short-term memory for matrices of increasing complexity was exhibited by the right frontal-lobe group. Right temporal lobectomy impaired cued recall of visually homogeneous matrices at each of four serial positions. On the delayed recognition of complex visual scenes, right temporal lobectomy decreased identification of changes in figurative detail and spatial composition, whereas right hippocampectomy impaired identification of changes in spatial location. The interplay between verbal and pictorial codes in memory was also investigated using related word-design pairs. Right or left temporal lobectomy affected the number of designs recalled but only the right temporal-lobe group produced designs of poor quality. When cued with the words, the left temporal-lobe group produced fewer designs than the control subjects, demonstrating a reduced ability to retrieve pictorial information through verbal labels.