A series of studies is described here which explore the functional organisation of face- and object-processing neurones in the adult vervet monkey brain. This fundamental issue in high-level vision is addressed by the use of a novel molecular mapping technique that was developed for this purpose. / In the first study, the temporal dynamics of c-fos and zif268 expression were delineated in detail in the rat visual cortex. Knowing the precise temporal parameters of up-regulation (after onset of sensory stimulation) and down-regulation (after offset of sensory stimulation) of these genes was integral to optimising the temporal aspects of the stimuli to be used for subsequent mapping experiments. This study provided the critical information for devising stimuli with corresponding temporal parameters to those of c-fos or zif268 so that one could take advantage of the disparity between the expression of their mRNA and protein products in order to visualise activated neurones. / In the second study, the newly developed molecular mapping technique was validated in the rat auditory, visual and multisensory systems. First, bimodal audiovisual stimuli were designed using the data obtained from the first study. Then, through the combined histological detection of the mRNA and protein products of zif268, discrete populations of neurones responsive to either component of the bimodal stimulus were visualised. It was also observed that a third population of neurones was found that responded to the stimulation through both sensory modalities. The combined results from these two studies set the stage for addressing the issue of the organisation of face- and object-selective neurones of the inferior temporal cortex in the vervet monkey brain. / In the third study, the functional organisation of face- and object-selective neurones was examined using the molecular mapping technique. Based on the data gathered from the first two studies, suitable stimuli containing two distinct object classes (conspecific faces and non-face familiar objects) were designed with appropriate temporal parameters. / Finally, the last study provided an opportunity to address the issue of hemispheric asymmetry of function in the context of face processing in the non-human primate brain. Results support the notion that there may indeed be phylogenetic explanations for the hemispheric asymmetry observed in the human brain.

Researchers in the field of social learning have suggested that certain biases may exist in whom animals learn from, creating a non-random flow of social information. A number of potential biases have been proposed based upon theoretical models, including biases to copy more dominant individuals or individuals who receive the best payoff from their behaviour, but empirical evidence for these biases is lacking. This thesis presents the first examination of dominance-based bias in a wild population of primates and of a payoff-based bias in captive capuchins. In two field experiments, dominant and low-ranking females from each of three wild groups of vervet monkeys (Chlorocebus aethiops pygerythrus) in KwaZulu-Natal, South Africa were trained to demonstrate contrasting behaviours to their group before observers were provided with a choice between the two modelled preferences. No evidence was found for a consistent bias to copy the behaviour of the dominant female in either experiment. Instead, in both experiments, a preference for one behaviour emerged, regardless of model rank. In the latter experiment, higher-ranking females were significantly more likely to match the dominant model's action than were low-ranking females. The low-ranking models were more likely than their high-ranking counterparts to switch behaviours, despite their trained behaviour continuing to be productive. An analyses of the observations revealed that observers were biased towards attending to kin, and observer age appeared to influence access to the dominant models, but no overall preference to attend to the dominant female was found. Together these findings indicate that kinship, sex, age and preferences for specific behaviours are more important factors than model rank in vervet monkey social learning. Finally, I examined whether captive tufted capuchins (Sapajus apella) utilized a payoff-based social learning bias in their foraging decisions. Subjects did not utilize public information when choosing between demonstrated resource-rich and resource-poor sites, suggesting that the social learning abilities of capuchins may not extend to determining the profitability of feeding sites, although limitations of the study are discussed.

No description available.

The permanent coresidence of males within a troop is unusual but occurs in vervet monkeys. Several hypotheses have been projected to explain the coexistence of male vervets (predation risk, breeding season length) but these hypotheses fall short in explaining the multimale nature of vervet monkeys. In order to determine the explanation for coresiding males, I collected male behavioural data from two troops over the course of nine months. My dataset was divided into two categories, male-male interactions and female-male interactions. The male-male data indicate that breeding season is the most active time for migration, aggressions and wounds. Coalitions were described for the first time, and affiliative interactions between males highlighted coping tactics of males in regards to their coexistence. The female-male data indicate there was little indication for distinct male or female choice for mating. Specifically, olfactory information appears to lower successful copulations of males, and female resistance also decreased successful copulations. Grooming was not a commodity traded for mating access. Male dominance was not correlated with mating success, and females seem to express their preference for sexual partners. The large cohort of males of my troops appears to alter behaviours observed at other sites. The maintenance of male-female associations after breeding season suggests that males may be preparing for next breeding season, and males may co-reside for breeding purposes. / xiii, 123 leaves : ill. maps ; 29 cm

This study explored the organizing principles of female sociality in free-ranging vervet monkeys (Chlorocebus aethiops) inhabiting the Klein Karoo, South Africa. Females groomed more than males, grooming peaked at the end of the day and less grooming occurred during the mating season. Although females competed over food, they did not compete over grooming partners, rarely formed coalitions and did not trade grooming against other activities. Instead, they maintained grooming whilst trading between feeding and resting and feeding and moving. Despite seasonal shifts in food competition, grooming was not traded for tolerance and there was an upper limit to cohort size before clique size declined. Inter-population comparisons revealed no troop size effects on clique size, aggression and competition over high-ranking grooming partners. The rarity of coalitions suggests coalitions are unlikely to be a central component of female relationships. / xiii, 162 leaves : ill., maps ; 29 cm

No / The surface expression and regulated endocytosis of kainate (KA) receptors (KARs) plays a critical role in neuronal function. PKC can modulate KAR trafficking, but the sites of action and molecular consequences have not been fully characterized. Small ubiquitin-like modifier (SUMO) modification of the KAR subunit GluK2 mediates agonist-evoked internalization, but how KAR activation leads to GluK2 SUMOylation is unclear. Here we show that KA stimulation causes rapid phosphorylation of GluK2 by PKC, and that PKC activation increases GluK2 SUMOylation both in vitro and in neurons. The intracellular C-terminal domain of GluK2 contains two predicted PKC phosphorylation sites, S846 and S868, both of which are phosphorylated in response to KA. Phosphomimetic mutagenesis of S868 increased GluK2 SUMOylation, and mutation of S868 to a nonphosphorylatable alanine prevented KA-induced SUMOylation and endocytosis in neurons. Infusion of SUMO-1 dramatically reduced KAR-mediated currents in HEK293 cells expressing WT GluK2 or nonphosphorylatable S846A mutant, but had no effect on currents mediated by the S868A mutant. These data demonstrate that agonist activation of GluK2 promotes PKC-dependent phosphorylation of S846 and S868, but that only S868 phosphorylation is required to enhance GluK2 SUMOylation and promote endocytosis. Thus, direct phosphorylation by PKC and GluK2 SUMOylation are intimately linked in regulating the surface expression and function of GluK2-containing KARs.

No / Flavonoids are plant-derived polyphenolic compounds with neuroprotective properties. Recent work suggests that, in addition to acting as hydrogen donors, they activate protective signalling pathways. The anti-oxidant response element (ARE) promotes the expression of protective proteins including those required for glutathione synthesis (xCT cystine antiporter, gamma-glutamylcysteine synthetase and glutathione synthase). The use of a luciferase reporter (ARE-luc) assay showed that the dietary flavan-3-ol (-)epicatechin activates this pathway in primary cortical astrocytes but not neurones. We also examined the distribution of NF-E2-related factor-2 (Nrf2), a key transcription factor in ARE-mediated gene expression. We found, using immunocytochemistry, that Nrf2 accumulated in the nuclei of astrocytes following exposure to tert-butylhydroquinone (100 microM) and (-)epicatechin (100 nM). (-)Epicatechin signalling via Nrf2 was inhibited by wortmannin implicating a phosphatidylinositol 3-kinase-dependent pathway. Finally, (-)epicatechin increased glutathione levels in astrocytes consistent with an up-regulation of ARE-mediated gene expression. Together, this suggests that flavonoids may be cytoprotective by increasing anti-oxidant gene expression.