Neuroscience and Neurobiology Commons^™

Reaching For The Light: The Prioritization Of Conspicuous Visual Stimuli For Reflexive Target-Directed Reaching, Daniel K. Wood

Electronic Thesis and Dissertation Repository

The degree to which something stands out against the background of its environment communicates important information. The phenomenon of camouflage is a testament of the degree to which visual salience and probability of survival tend to overlap. Salient stimuli often elicit fast, reflexive movements in order to catch prey or avoid a predator. The overarching goal of the work presented in this thesis is to investigate how the physical salience of visual stimuli influence the programming and execution of reaching movements. I approached this question by recording kinematics and muscle responses during reaching movements. Broadly, this thesis investigates the effect …

Contribution Of Trpm2 To Memory Loss In An Alzheimer's Mouse Model, Megan M. Chen

Electronic Thesis and Dissertation Repository

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by the progressive deterioration of memory and other intellectual abilities. Accumulation of amyloid-β (Aβ) peptide, the major contributor to the senile plaques central to AD, is thought to mediate neurotoxicity by inducing oxidative stress and calcium dysregulation. Transient Receptor Potential Melastatin type 2 (TRPM2) is a calcium permeable, non-selective cation channel activated under oxidative stress and ultimately induces cell death. The APPSWE/PSEN1ΔE9 double transgenic mouse model carries the human APPswe (Swedish mutations K594N/M595L) and PS1 mutations with a deletion in exon 9 (PS1-dE9), and is one of the most commonly used AD …

Dopamine Modulation Of Emotional Learning In The Medial Prefrontal Cortex, Nicole M. Lauzon

Electronic Thesis and Dissertation Repository

Dopamine (DA) transmission plays a critical role in the processing of emotionally salient information and in associative learning and memory processes. Within the mammalian brain, neurons within the medial prefrontal cortex (mPFC) are involved critically in the encoding, expression, and extinction of emotionally salient learned information. Within the mPFC, DAergic transmission is involved importantly in controlling attention related and motivational processes, particularly within the context of emotionally salient sensory information. Considerable evidence suggests differential roles for DA D₁-like versus D₂-like receptors, including the D₄-receptor subtype, in the regulation of neuronal activity and emotional processing …

Exploring The Neural Basis Of Top-Down Guided Action In Macaque Monkeys, Jessica M. Phillips

Electronic Thesis and Dissertation Repository

To thoroughly characterize any brain mechanism requires an appropriate animal model for invasive studies. An invaluable model system used toward a comprehension of cognitive neurophysiology is the macaque monkey. It is important to delineate similarities and limitations for this model in relation to the human brain and cognition. In this thesis, we have thus conducted three experiments to investigate putative generalizations between monkeys and humans regarding the neural processes associated with top-down action control in monkeys.

Our daily behaviour is largely comprised of automatic routine actions. The frequent repetition of certain behaviours in response to particular contexts can give rise …

Circadian Rhythms In Reward And Underlying Neural Circuits, Ricardo M. Baltazar

Electronic Thesis and Dissertation Repository

Studies suggest that the circadian timing system exerts an important influence on responses to rewarding stimuli. Diurnal rhythms in the rewarding value of amphetamine and mating behavior were observed, but differed in the pattern of their timing. Daily fluctuations in reward were correlated with oscillations in mesolimbic dopaminergic activity in both the nucleus accumbens (NAc) and ventral tegmental area (VTA), with a peak in NAc coinciding with the peak of sex reward, while the peak in the VTA associated with the peak in amphetamine reward. Also, rhythmic expression of the marker of neural activation, cFos, was observed in NAc, medial …

Loss Of Dendritic Inhibition In The Hippocampus After Repeated Early-Life Hyperthermic Seizures In Rats., Richard Boyce, L Stan Leung

Physiology and Pharmacology Publications

Seizures are relatively common in children and are a risk factor for subsequent temporal lobe epilepsy. To investigate whether early-life seizures themselves are detrimental to the proper function of the adult brain, we studied whether dendritic excitation and inhibition in the hippocampus of adult rats were altered after hyperthermia-induced seizures in immature rats. In particular, we hypothesized that apical dendritic inhibition in hippocampal CA1 pyramidal cells would be disrupted following hyperthermia-induced seizures in early life. Seizure rats were given three hyperthermia-induced seizures per day for three days from postnatal day (PND) 13 to 15; control rats were handled similarly but …