Anatomical Substrates For Primate Executive Cortical Function
Funder
National Health and Medical Research Council
Funding Amount
$362,820.00
Summary
When studying the brain, many have been tempted to look for similarities in organization of cells and circuitry in different regions involved in various processes. While, at a first approximation, this may be a reasonable approach to understand how the brain works, it also ignores what makes the brain so complex: the diversity in its structure. In the late 19th, and early 20th, centuries, pioneering anatomists seized on the diversity in structure of the human brain. The study of cortical circuit ....When studying the brain, many have been tempted to look for similarities in organization of cells and circuitry in different regions involved in various processes. While, at a first approximation, this may be a reasonable approach to understand how the brain works, it also ignores what makes the brain so complex: the diversity in its structure. In the late 19th, and early 20th, centuries, pioneering anatomists seized on the diversity in structure of the human brain. The study of cortical circuitry that underlies the diversity in cortical processing reached a zenith and there was a renaissance in understanding of brain function. These researchers were, however, limited by techniques available to them at the time. With the advent of new methodologies which allowed scientists to explore individual connections between cells (synapses), to probe structure and transmission across synapses, and to record from live neurones, new and exciting discoveries were made. However, these methodologies are highly time consuming and studies became necessarily more focussed. As a result, there was a tendency in the later half of the 20th century to extrapolate findings from one cortical area to cortex in general. Even more precarious, anatomical and functional findings in highly specialized sensory cortex of one species were projected to other distantly related species. Such thinking lead to a dark age in neuroscience. It became widely accepted that there exists a canonical circuit. Consequently, differences in function between different cortical areas were attributed solely to the source of their projections. The central thesis of this project is to study aspects of cell structure and cortical circuitry in the prefrontal lobe. We hope that the project will provide another step in the pathway that leads to understanding the mind.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.
Lesions of the primary visual area (V1) are sufficient to cause blindness, even though there are many other brain areas normally involved in vision. However, when V1 is lesioned very early in life people show some recovery, and may be able to see well enough to perform everyday activities. In order to understand what happens in the brain that allows this preservation of vision, we will study changes in the pathways linking the eyes to the brain, following lesions at different ages.
Combining input from vision and hearing greatly enhances perception when information from one of these senses is degraded or incomplete, such as when tracking objects in foggy, dark or noisy places. This enhancement is of considerable importance because degraded input is the daily situation faced by many people with hearing or vision impairment. We will study the neural processes underlying our ability to combine vision and hearing to create a more reliable and accurate perception of the world.
One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. We will address one particular aspect of this problem, namely the organisation of the cortical areas that provide visual control for skilled movement ....One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. We will address one particular aspect of this problem, namely the organisation of the cortical areas that provide visual control for skilled movements. It is proposed that there are two parallel brain circuits involved in the analysis of motion, one tracking the movement of objects, and the other analysing a person s self-motion. Consider, for example, the task of a tennis player who has to return a serve. In order to achieve this, the brain must precisely integrate information about the ball s motion, as well as information about the player s speed and direction. This requires precise control of eye movements (to keep the eyes on the ball), as well as the ability to control the limb and trunk muscles. The aim of this study will be to map the anatomical framework underlying our ability to process all the relevant visual motion information, and to coordinate the appropriate motor responses. Such work is fundamental for understanding the functional organisation of the brain. It also has the potential to lay the groundwork for developments in areas of applied research, including medicine (e.g. the design of better rehabilitation strategies for people with brain damage), robotics- artificial intelligence (e.g. the improvement of artificial systems capable of vision), and the cognitive sciences (e.g. a better understanding of factors that limit human responses to visual stimuli).Read moreRead less
One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. In this project, we will address the organization of a poorly known group of visual areas, which is located deep in a part of the brain called the in ....One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. In this project, we will address the organization of a poorly known group of visual areas, which is located deep in a part of the brain called the interhemispheric fissure (the medial complex of visual areas). Preliminary evidence suggests that these areas may provide anatomical shortcuts linking vision, behavioural reactions, and emotion. Suppose, for example, that you are sitting outside reading. Although deep in concentration, you are still able to detect the sudden movement of an approaching object in your peripheral field of vision. In many cases you can react (e.g., by ducking , or raising your arms to protect the face) long before you register what the object actually is. An adrenaline rush often accompanies these quick motor reactions, implying a parallel activation of the autonomic nervous system. While the mechanism by which the brain promotes these quick reactions remains poorly understood, we believe that the medial complex of visual areas holds the key. The aim of this study is to map the anatomical framework underlying our ability to react to sudden stimuli in our peripheral visual field. Such work is fundamental for understanding the functional organization of the brain. It also has the potential to lay the groundwork for developments in areas of applied research, including medicine (e.g. the design of better rehabilitation strategies for people with brain damage) and the cognitive sciences (e.g. a better understanding of the factors that limit human responses to visual stimuli).Read moreRead less
Over thirty different areas, comprising nearly half the primate cerebral cortex, are involved in processing visual information. From the anatomical viewpoint, each of these areas should be capable of receiving visual information independently, through parallel anatomical channels involving the brainstem. Yet, it has been observed that lesion of one particular area (the primary visual area, V1) results in loss of vision. This raises several questions. What type of visual information is carried by ....Over thirty different areas, comprising nearly half the primate cerebral cortex, are involved in processing visual information. From the anatomical viewpoint, each of these areas should be capable of receiving visual information independently, through parallel anatomical channels involving the brainstem. Yet, it has been observed that lesion of one particular area (the primary visual area, V1) results in loss of vision. This raises several questions. What type of visual information is carried by the parallel pathways to the other visual areas? Why aren t these other areas capable of sustaining vision without V1? Do V1 lesions trigger changes in the adult brain, which affect the other visual areas? As a step towards answering these questions, we will study the neural pathways that convey visual information directly to the middle temporal area (MT). MT is one of the best-characterised visual areas, and the anatomy of its neural inputs is well known, facilitating the interpretation of the results. We will investigate the type of visual information being sent to MT after lesions of V1, as well as the changes in the electrical responses of MT cells which result from this type of condition. This is a basic science study, the primary benefit of which will be advancement of knowledge on the mechanisms that underlie visual processing in normal and pathological situations. However, this type of work may also lay the groundwork for developments in areas of applied research. These may include medicine (e.g. the design of better rehabilitation strategies for people with brain damage), robotics- artificial intelligence (e.g. the development of more robust artificial systems capable of vision), and cognitive sciences (e.g. a better understanding of factors that limit human responses to visual stimuli).Read moreRead less