Synaptic Integration And Plasticity In The Rat Piriform Cortex
Funder
National Health and Medical Research Council
Funding Amount
$250,500.00
Summary
The human cerebral cortex is the pinnacle of evolution. It is the most complex structure known, responsible for all of those skills - like language and reasoning - that make our species so remarkable. It is also a major site of many brain diseases, like schizophrenia and epilepsy. An understanding of how the cerebral cortex works would be a remarkable achievement, of immeasurable benefit to human health. How can one go about studying such a complex structure? The strategy taken in this project i ....The human cerebral cortex is the pinnacle of evolution. It is the most complex structure known, responsible for all of those skills - like language and reasoning - that make our species so remarkable. It is also a major site of many brain diseases, like schizophrenia and epilepsy. An understanding of how the cerebral cortex works would be a remarkable achievement, of immeasurable benefit to human health. How can one go about studying such a complex structure? The strategy taken in this project is to begin by studying one of the simplest regions of the cerebral cortex, the olfactory (or piriform) cortex. The olfactory cortex is an evolutionarily ancient region of cortex, with a simpler architecture than other cortical regions. Its task is to process the sense of smell, a primitive sense that is more elaborated in lower animals than in humans. The broad goal of our research is to understand, by studying the olfactory cortex of rats, how olfactory processing occurs at the level of nerve cells (neurons). We will use a number of powerful techniques - including microelectrode recording and laser microscopy - to measure the electrical properties of individual neurons. We will also study the synaptic connections between neurons, and how these connections change following memory-inducing stimuli. It is hoped that this work will shed light on how the healthy cortex is able to process and store information, and how brain diseases cause these functions to deteriorate.Read moreRead less
A decade ago the adult brain was thought of as a structurally-fixed organ. Against this are well-documented cases of slow recovery after massive injuries or stroke. Simple models of brain injury using the tactile, visual and auditory systems of animals as models have now revealed multiple stages of recovery (plasticity). Some of these are inbuilt into the wiring of the neural systems such that functional plasticity can result without the need for any structural or cellular changes. A second grou ....A decade ago the adult brain was thought of as a structurally-fixed organ. Against this are well-documented cases of slow recovery after massive injuries or stroke. Simple models of brain injury using the tactile, visual and auditory systems of animals as models have now revealed multiple stages of recovery (plasticity). Some of these are inbuilt into the wiring of the neural systems such that functional plasticity can result without the need for any structural or cellular changes. A second group of plastic phenomena depend upon minute changes in the connections between neurons and these are invoked in the first few days following an injury (synaptic plasticity; changes in the pattern and strength of the connections between neurons). Aside from being model systems, there are also parallels of this plasticity with clinical situations such as losses in hearing and sight, and of the adaptations made by the brain in response to prosthetics (e.g. bionic ear) and resorative surgery but the degree of relevance for these situations is unclear. An intriguing aspect of the experiments on auditory and visual systems is that neurons with inputs from both ears, or both eyes, undergo the plastic changes when the relevant sense organ on only one side is damaged but the other is intact. In fact, on the basis of the limited available evidence, it appears that the changes are independent of there being a normal input from the other side. This is difficult to explain in terms of the modern understanding neuronal plasticity at a cellular level. It is thus proposed to study both auditory and visual models of this brain plasticity with stimuli which are systematically varied to extract the extent of bilateral interaction in the induced plasticity. This will enable prediction of how these plasticity mechanisms will be involved in adaptations made to prosthetics and surgical corrections.Read moreRead less
Learning And Network Plasticity In A Primitive Sensory Cortex
Funder
National Health and Medical Research Council
Funding Amount
$461,557.00
Summary
Our brain is a uniquely powerful supercomputer, in part because it is ‘plastic’ -- that is, it can change itself when we adapt or learn something new. An understanding of the causes of brain plasticity is an essential part of any quest to understand the brain in sickness and in health. This research uses a laser microscope to ‘read the minds’ of mice as they learn about odours. By observing plasticity in action, we will gain deeper insights into normal brain function.
Properties Of Dendritic Spines And Their Role In Synaptic Plasticity
Funder
National Health and Medical Research Council
Funding Amount
$336,767.00
Summary
Connections between nerve cells in the brain often occur onto enlarged protrusions called dendritic spines. This proposal will investigate the properties of dendritic spines, and relate differences in spine properties to synaptic plasticity. This information can be used to better understand and treat neurological disorders associated with spine malfunction, as occur in some forms of mental retardation, and may help with understanding the memory loss that occurs during ageing and dementia.
The research described in this Project Grant application should help to us understand how our brains make memories. Our brains contain billions of interconnected nerve cells forming unimaginable numbers of possible networks. Previous research indicates that repetitive activation of individual networks can lead to changes in the strength of connections between nerve cells. These changes in connection strength are thought to underlie learning and memory. The experiments described in this proposal ....The research described in this Project Grant application should help to us understand how our brains make memories. Our brains contain billions of interconnected nerve cells forming unimaginable numbers of possible networks. Previous research indicates that repetitive activation of individual networks can lead to changes in the strength of connections between nerve cells. These changes in connection strength are thought to underlie learning and memory. The experiments described in this proposal will address the mechanisms underlying changes in the strength of connections between nerve cells. As most of the inputs nerve cells receive from other nerve cells are made onto their dendrites (small branching processes that extend from the cell body), the main objective is to investigate the interactions at the dendritic level responsible for changes in connection strength. The results of this work will raise our understanding of how memories are formed, which will be essential if we are to understand the cellular processes disrupted during memory dysfunction in neurological disorders such as dementia.Read moreRead less
Plasticity Of Sensorimotor Representations In Adult Primate Cortex
Funder
National Health and Medical Research Council
Funding Amount
$554,656.00
Summary
Cells in some regions of the brain, collectively known as the sensorimotor cortex, control our capacity to purposefully move the arms and hands. Damage to these regions in adults causes severe deficits. However, rehabilitative training can restore some control over the muscles. To understand how the brain circuits change to compensate for injury, and what effect rehabilitation may have on these changes, I will study cellular alterations in the movement control pathways in the cerebral cortex.
Molecular And Cellular Changes Following A Cortical Injury: What Role Do They Play In Regeneration?
Funder
National Health and Medical Research Council
Funding Amount
$499,625.00
Summary
Damage to the visual areas of the brain is common after, for example stroke, neurotrauma or hypoxia. The injury often manifests in the form of a scar caused by a specific type of brain cell (astrocyte). This scar acts as a barrier to the cells which transmit information (neurones), preventing re-establishment of connectivity, thus functional recovery. We will see if we can reduce this scar and enhance re-connectivity after injury by blocking some of the molecules that brain cells express.