Neural Circuits For Active Vision In The Primate Cerebral Cortex
Funder
National Health and Medical Research Council
Funding Amount
$632,938.00
Summary
This project will try to understand how we use visual information to identify objects by their shape and motion, in natural situations in which the eyes are moving all the time. This will be accomplished by recording the electrical activity of brain cells while a trained animal is performing different types of tasks, such as tracking a moving object or exploring a scene with its eyes.
We are able to identify and discriminate objects in the world because of exquisitely detailed and rapid processing of sensory information by neurons in the cortex of the brain. In this project we will examine these operations in neurons in the cortex that receive input from the large face whiskers of the rat. These whiskers are used for fine-grain discrimination and for gauging distance. They are deflected by being actively moved, under muscle control, over objects (active touch) or by being pas ....We are able to identify and discriminate objects in the world because of exquisitely detailed and rapid processing of sensory information by neurons in the cortex of the brain. In this project we will examine these operations in neurons in the cortex that receive input from the large face whiskers of the rat. These whiskers are used for fine-grain discrimination and for gauging distance. They are deflected by being actively moved, under muscle control, over objects (active touch) or by being passively deflected by objects. Deflection results in inputs to the brain that are processed to form the neural basis for very finely detailed perceptual behaviour. In rats, with impoverished visual and auditory senses, the whiskers are the major sensory system for interacting with the world, and are used in navigating the environment and in finding and distinguishing foods. Thus they contribute strongly to the remarkable success of this species. This elegant sensory system has a number of advantages that make it a very good model for the study of brain mechanisms responsible for active fine-grain sensory function. We plan to take advantage of the unique features of this system to define the information processing that occurs in the cortex in this elegantly complex system. This will address an issue relevant to all sensory systems - namely the neural basis of complex fine grain perceptual behaviour. Understanding the mechanisms underlying active tactile perception also has relevance to clinical conditions involving deficits in active touch e.g., in diabetic polyneuropathy (which eventually affects ~50% of diabetics), in leprosy (in which an early sign is damage to active touch). Knowledge of the core brain processes in active touch gained in this study could eventually underpin the ameliorative technologies for such deficits.Read moreRead less
Position perception, attention, object motion, and action. The research will achieve a deeper understanding of the neural processing of the visual perception of position, and of the associated behavioural limits. This will provide a foundation for the development of a range of technologies to assist disabled and elderly people. The results will help reveal the link between the perception of moving objects and the capacity for visually guided movement. This link will benefit areas such as enginee ....Position perception, attention, object motion, and action. The research will achieve a deeper understanding of the neural processing of the visual perception of position, and of the associated behavioural limits. This will provide a foundation for the development of a range of technologies to assist disabled and elderly people. The results will help reveal the link between the perception of moving objects and the capacity for visually guided movement. This link will benefit areas such as engineering of vehicles and road systems, and the design of telepresence systems. The first applications are likely to be in the rehabilitation of brain injury and the decline of mental function with age.Read moreRead less
Sensory Coding Mechanisms in Rat Somatosensory System; A Combined Behavioural and Electrophysiological Approach. This inter-disciplinary project spans behavioural sciences, neurophysiology and computational neuroscience. It investigates fundamental questions such as how different aspects of stimuli are presented in sensory areas of the brain and how the animal interprets the neuronal activity in such areas to generate the relevant behaviour. A major problem with making prosthetic sensory devices ....Sensory Coding Mechanisms in Rat Somatosensory System; A Combined Behavioural and Electrophysiological Approach. This inter-disciplinary project spans behavioural sciences, neurophysiology and computational neuroscience. It investigates fundamental questions such as how different aspects of stimuli are presented in sensory areas of the brain and how the animal interprets the neuronal activity in such areas to generate the relevant behaviour. A major problem with making prosthetic sensory devices is the way by which these devices can communicate with the brain. Research into the coding of different features of simple stimuli will provide basic knowledge which can be implemented in prosthetic sensory devices. Read moreRead less
The advantage of being magnocellular: the role of the dorsal visual stream in object identification. The primary benefit of this project is to basic science and tertiary teaching globally. Visual processing and how it activates attention and operates to guide actions and cognitive behaviour is fundamental to our understanding of life and brain evolution. In particular this new knowledge will further understanding of many cognitive symptoms associated with neurodevelopmental disorders and in the ....The advantage of being magnocellular: the role of the dorsal visual stream in object identification. The primary benefit of this project is to basic science and tertiary teaching globally. Visual processing and how it activates attention and operates to guide actions and cognitive behaviour is fundamental to our understanding of life and brain evolution. In particular this new knowledge will further understanding of many cognitive symptoms associated with neurodevelopmental disorders and in the future should lead to design of better educational technologies for such children. Similarly understanding of temporal sequencing of vision has commercial implications for design of bionic eyes and robotic vision processing.Read moreRead less
Chromatic Inputs to Cortical Receptive Fields in Primates. The human eye contains three kinds of receptors for daytime vision, named blue, green and red cones for their sensitivity to different regions of the visible spectrum. It is known that blue cones contribute to brain pathways for colour vision, but recent data suggest there is also 'cross-talk' of blue cone signals to pathways for motion and high-acuity vision. This project comprises precise measurement of blue cone signals, and anatomica ....Chromatic Inputs to Cortical Receptive Fields in Primates. The human eye contains three kinds of receptors for daytime vision, named blue, green and red cones for their sensitivity to different regions of the visible spectrum. It is known that blue cones contribute to brain pathways for colour vision, but recent data suggest there is also 'cross-talk' of blue cone signals to pathways for motion and high-acuity vision. This project comprises precise measurement of blue cone signals, and anatomical tracing of blue cone pathways, in a primate model for human vision. The data will improve our basic knowledge of how the brain processes sensory signals.Read moreRead less
Neuronal Activity And Functional Magnetic Resonance Imaging (fMRI)
Funder
National Health and Medical Research Council
Funding Amount
$367,561.00
Summary
How does brain activity relate to perception and behaviour? How does functional magnetic resonance imaging (fMRI) of the brain, which measures changes in blood oxygen, relate to the activity of single cells? I will address these questions, comparing electrical measurements of single cells and functional images, and advance our understanding of the brain in health and disease.
Brain mechanisms for coordinating with others through sound. Distinguishing between sounds produced by self and others is critical for interpersonal coordination and communication through speech and music. This project employs a novel dual-brain electrophysiological technique with tagged audio signals to elucidate how the human brain achieves this distinction, and when and why it cannot. Expected outcomes include new knowledge on the neurophysiological mechanisms that support self-other processi ....Brain mechanisms for coordinating with others through sound. Distinguishing between sounds produced by self and others is critical for interpersonal coordination and communication through speech and music. This project employs a novel dual-brain electrophysiological technique with tagged audio signals to elucidate how the human brain achieves this distinction, and when and why it cannot. Expected outcomes include new knowledge on the neurophysiological mechanisms that support self-other processing, and the acoustic conditions and behavioural strategies that facilitate their operation. These outcomes should ultimately have applied benefits for improving interpersonal coordination and social interaction, especially in digital environments and clinical populations with atypical self-other processing.Read moreRead less
Imaging supra- versus sub-threshold perception: Towards a neural 'signature' of conscious experience. This is the first study to combine spatial and temporal brain measures to test the prediction that 'conscious' (versus 'unconscious') emotion perception is distinguished by responses in cortical brain regions, and by later peaks in integrative brain activity. Two additional innovative features include the simultaneous measurement of arousal (as an independent index of responses to emotion, regar ....Imaging supra- versus sub-threshold perception: Towards a neural 'signature' of conscious experience. This is the first study to combine spatial and temporal brain measures to test the prediction that 'conscious' (versus 'unconscious') emotion perception is distinguished by responses in cortical brain regions, and by later peaks in integrative brain activity. Two additional innovative features include the simultaneous measurement of arousal (as an independent index of responses to emotion, regardless of conscious awareness), and the use of psychophysical methods to establish objective thresholds for 'unconscious' and 'conscious' perception. Elucidating the neural basis of conscious emotion perception is important to understanding the mechanisms of unique human experience, and disorders of stress and anxiety.Read moreRead less
Presynaptic mechanisms of general anaesthesia in the fly brain. General anaesthesia is a routine procedure for both human and veterinary surgery and for any experimental paradigms requiring immobilization of animals. By abolishing consciousness, these drugs provide practitioners with an ideal way of manipulating subjects under conditions when responsiveness might be undesirable. Understanding how manipulating synaptic release mechanisms might modulate anaesthetic potency will be valuable for eve ....Presynaptic mechanisms of general anaesthesia in the fly brain. General anaesthesia is a routine procedure for both human and veterinary surgery and for any experimental paradigms requiring immobilization of animals. By abolishing consciousness, these drugs provide practitioners with an ideal way of manipulating subjects under conditions when responsiveness might be undesirable. Understanding how manipulating synaptic release mechanisms might modulate anaesthetic potency will be valuable for eventually being able to better control the anaesthetized state in human and animal subjects. By understanding general anaesthesia across multiple levels of brain function, we will at the same time be answering fundamental questions pertaining to mechanisms of perception and awareness. Read moreRead less