The Role Of Corticothalamic Feedback On The Response Dynamics Of Thalamic Neurons
Funder
National Health and Medical Research Council
Funding Amount
$351,852.00
Summary
A fundamental question in neuroscience is how the brain selectively processes sensory information to generate a reliable representation of the world. Positioned in the centre of the brain, the thalamus plays a key role in sensory processing. This project investigates how the interaction between thalamus and cortex shapes the selection and gating of sensory information. This is a fundamental question in basic neuroscience with the potential to increase our knowledge about attentional deficits.
Does The Complement System Contribute To Neuropathic Pain?
Funder
National Health and Medical Research Council
Funding Amount
$262,958.00
Summary
Nerve injury often results in increased sensitivity to painful stimuli and the perception of innocuous stimuli as painful; it may also result in spontaneous pain. These disorders of pain sensation due to nerve injury are common, debilitating and difficult to treat. They are symptoms of neuropathic pain. Pain is normally signalled to the brain by sensory nerve cells called nociceptors. Following nerve injury, nociceptors are sensitised by chemicals released by inflammatory cells. This contributes ....Nerve injury often results in increased sensitivity to painful stimuli and the perception of innocuous stimuli as painful; it may also result in spontaneous pain. These disorders of pain sensation due to nerve injury are common, debilitating and difficult to treat. They are symptoms of neuropathic pain. Pain is normally signalled to the brain by sensory nerve cells called nociceptors. Following nerve injury, nociceptors are sensitised by chemicals released by inflammatory cells. This contributes to neuropathic pain. We have evidence that inflammatory responses play a key role in initiating neuropathic pain. Other evidence suggests that the immune system contributes to neurological diseases and accompanying pain (e.g. Guillain-Barr syndrome and multiple sclerosis). We plan to test the idea that a component of the immune system known as the complement pathway contributes to the development of neuropathic pain following peripheral nerve injury. The outcome of this work will be a better understanding of the way in which nerve injury leads to chronic disorders of pain, including increased sensitivity to painful stimuli. This will lead in turn to the development of more effective treatments for neuropathic pain.Read moreRead less
Integration Of Information By Cells In Mammalian Visual Cortices: Role Of Feedforward And Feedback Inputs.
Funder
National Health and Medical Research Council
Funding Amount
$294,098.00
Summary
In highly 'visual' mammals, such as humans or domestic cats information channels originating in the retina extract and process in parallel information about certain features of the visual world such as shape or motion. The extracted information is sent to the primary visual cortex in the brain. The primary visual cortex 'distributes' this information to different 'higher-order' cortical areas which process the information further. Nerve cells in visual cortices have clearly defined receptive fie ....In highly 'visual' mammals, such as humans or domestic cats information channels originating in the retina extract and process in parallel information about certain features of the visual world such as shape or motion. The extracted information is sent to the primary visual cortex in the brain. The primary visual cortex 'distributes' this information to different 'higher-order' cortical areas which process the information further. Nerve cells in visual cortices have clearly defined receptive fields (RFs), that is, regions of the visual space from which appropriate visual stimuli will activate the cell. Contrary to the previous assumptions however, many of the basic RF properties of cortical neurones are not static but appear to depend on constant dynamic interplay between different components of nerve network in which the neurones are embedded. We wish to study the dynamic changes in the spatial structure of RFs of single neurones in mammalian primary visual cortex. We will examine changes in the structure of RFs of shape processing neurones when low contrast, large visual stimuli are presented. Since the low contrast stimuli extending beyond the confines of RFs of cortical neurones are akin to those in the natural visual scenes we hope to gain insights concerning mechanisms underlying perceptual processing of shapes in natural scenes. We will also study the spatial organization of RFs of neurones in primary visual cortex during reversible inactivation of higher-order visual areas. This will allow us to gain insights concerning the role of 'feedback' projections from the higher-order areas. Furthermore, we will study the responses of cells in one of the higher-order motion processing cortical areas. Comparing the responses in this area to complex motions during normal conditions with those during reversible inactivation of one of the reciprocally connected areas will provide us with insights concerning the mechanisms underlying processing of complex motions.Read moreRead less
Generation Of Complex Responses In Retinal Ganglion Cells
Funder
National Health and Medical Research Council
Funding Amount
$490,500.00
Summary
The retinal ganglion cells, whose axons form the optic nerve, comprise numerous distinct types, which respond to visual stimuli in either a simple or complex manner. The project will investigate how the complex responses of the direction-selective ganglion cells (DSGCs) and the local-edge-detector ganglion cells (LEDs) are generated. It appears that the retinal neurons providing inhibitory input to DSGCs and LEDs use different neurotransmitters, and the project will investigate how this shapes t ....The retinal ganglion cells, whose axons form the optic nerve, comprise numerous distinct types, which respond to visual stimuli in either a simple or complex manner. The project will investigate how the complex responses of the direction-selective ganglion cells (DSGCs) and the local-edge-detector ganglion cells (LEDs) are generated. It appears that the retinal neurons providing inhibitory input to DSGCs and LEDs use different neurotransmitters, and the project will investigate how this shapes the response properties of the ganglion cells. This will be done both by recording the visually evoked responses of the ganglion cells in an isolated preparation of the retina and by using two-photon laser-scanning microscopy to functionally image the neuronal interactions between the neurons that inhibit the DSGCs.Read moreRead less
THE AUTONOMIC, SOMATIC AND CENTRAL NEURAL RESPONSES TO DEEP AND SUPERFICIAL PAIN IN HUMAN SUBJECTS
Funder
National Health and Medical Research Council
Funding Amount
$375,750.00
Summary
Pain is a subjective experience, the intensity of which can be readily influenced by personal experience. Despite this, pain originating from a particular part of the body will usually be described by all individuals as having similar character. For example, pain arising from the skin is commonly described as being sharp or burning and is usually easy to localise, whereas pain arising from muscle is commonly dull, throbbing and diffuse. In addition to producing sensory changes, pain also evokes ....Pain is a subjective experience, the intensity of which can be readily influenced by personal experience. Despite this, pain originating from a particular part of the body will usually be described by all individuals as having similar character. For example, pain arising from the skin is commonly described as being sharp or burning and is usually easy to localise, whereas pain arising from muscle is commonly dull, throbbing and diffuse. In addition to producing sensory changes, pain also evokes changes in blood pressure, heart rate and motor activity (often in an attempt to remove the source of the pain). The proposed research aims to characterise the cardiovascular and motor patterns associated with pain originating in skin and in muscle and to examine the brain regions that produce these changes. More specifically, microelectrodes will be used to investigate changes in peripheral nerve activity during transient painful skin and muscle events in awake human subjects. In a separate investigation functional magnetic resonance imaging will be used to determine brain sites that are activated by skin or muscle pain.Read moreRead less
Operation of nerve cell networks in the neocortex. In humans, intellectual disabilities occur when nerve cells in the neocortex, the most complicated area of the brain, fail to function correctly. The goal of this project is to understand how neocortical areas communicate and how changes in the structure of neurons disturb their function; work that will lead to a better understanding of the operation of the neocortex.
Coding of olfactory information in the piriform cortex. This project aims to understand how electrical activity in the primary olfactory (piriform) cortex enables mice to recognise and remember odours. By using optical recording techniques together with genetic tools, the project expects to generate new knowledge about how the mammalian brain builds internal representations of the external world. Specific outcomes of the project include new insights into the functional architecture of the pirifo ....Coding of olfactory information in the piriform cortex. This project aims to understand how electrical activity in the primary olfactory (piriform) cortex enables mice to recognise and remember odours. By using optical recording techniques together with genetic tools, the project expects to generate new knowledge about how the mammalian brain builds internal representations of the external world. Specific outcomes of the project include new insights into the functional architecture of the piriform cortex and fresh understanding of how olfactory information is encoded and stored in neural circuits. More broadly, the project aims to advance our understanding of how the brain works, with benefits for future improvements in artificial intelligence and brain-machine interfaces.Read moreRead less
Functional imaging of colour pathways in the living eye. In order to repair or regenerate a diseased eye, we require knowledge of the normal pattern or nerve cell connections, and knowing how biology solves the problem of colour vision can be used to improve the design of artificial vision systems. The adaptive optics machine we will build in this project can be used to image nerve cells, fine blood vessels, and nerve fibre bundles in the normal and diseased eye. This will improve Australia's re ....Functional imaging of colour pathways in the living eye. In order to repair or regenerate a diseased eye, we require knowledge of the normal pattern or nerve cell connections, and knowing how biology solves the problem of colour vision can be used to improve the design of artificial vision systems. The adaptive optics machine we will build in this project can be used to image nerve cells, fine blood vessels, and nerve fibre bundles in the normal and diseased eye. This will improve Australia's research and development capacity in this new area of medical diagnostics. Our machine will be made available to other Australian laboratories and will improve the national capacity for making further scientific discoveries about how the visual system works.Read moreRead less
In the areas of the brain where visual information is processed, cells respond to the presentation of visual stimuli by changing their pattern of electrical activity. At the first level of analysis, the primary visual cortex (V1), individual cells become active only if line segments or borders of a particular orientation are present in their field of detection, which encompasses a small part of the visual scene. Cells in other visual cortical areas (the extrastriate cortex) perform more complex ....In the areas of the brain where visual information is processed, cells respond to the presentation of visual stimuli by changing their pattern of electrical activity. At the first level of analysis, the primary visual cortex (V1), individual cells become active only if line segments or borders of a particular orientation are present in their field of detection, which encompasses a small part of the visual scene. Cells in other visual cortical areas (the extrastriate cortex) perform more complex detection tasks in comparison with those in V1, which demand integration of information coming from much larger portions of the visual scene. One example of these more complex properties is the phenomenon of long-range contour integration, where our visual system groups individual line segments having similar orientations, so that they are perceived as part of the same contour. This property is reflected in the electrical responses of cells in the dorsomedial visual area (DM). How are properties such as orientation specificity and long-range contour integration created? To begin addressing this question, we will investigate correlations between the physiological properties of identified cells, the spatial distribution of their information collecting regions (dendrites), and the anatomical pathways by which they receive information from other parts of the brain. This is a basic science study aimed at determining the extent to which the anatomical structure of the brain helps define the function of individual cells and brain areas. Its primary benefit will be to increase our understanding of the mechanisms underlying all sensory processing in the brain. The knowledge obtained may also lead to developments in areas of applied research including medicine and cognitive science (for example, understanding how the brain learns to interpret visual information in early life, and how visual processing degrades with ageing).Read moreRead less