Organization And Function Of Primate Auditory Cortex
Funder
National Health and Medical Research Council
Funding Amount
$271,671.00
Summary
The conscious perception of speech and other sounds depends on processing within a brain region known as the auditory cortex. Compared to other brain areas, relatively little is known about the organization and function of this structure. Recent studies have proposed that the auditory cortex may be anatomically subdivided into functional modules, each of which is specialized for processing different types of information. However, the evidence for multiple processing streams is fragmentary, and n ....The conscious perception of speech and other sounds depends on processing within a brain region known as the auditory cortex. Compared to other brain areas, relatively little is known about the organization and function of this structure. Recent studies have proposed that the auditory cortex may be anatomically subdivided into functional modules, each of which is specialized for processing different types of information. However, the evidence for multiple processing streams is fragmentary, and not entirely consistent. The proposed experiments will combine anatomical and physiological approaches to evaluate the functional organization of auditory cortex in the primate brain. We will map the electrical responses of single brain cells to various complex sounds across the brain surface, and inject dyes to label pathways linking brain areas to one another. The data will allow us to determine whether specific subdivisions of the auditory cortex are specialized for processing different types of infomation, and whether specific subdivisions are linked together to form processing streams specialized for sound recognition and space perception. The results will advance our understanding of the neuronal processing involved in the perception of sound, with possible implications for speech perception. This will help to understand the consequences of brain damage, and may inform the development of hearing aids and artificial voice recognition systems. In addition, this study will help to develop a primate model for studying brain mechanisms of sound recognition that should be useful in research on cochlear implants.Read moreRead less
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.
Object Recognition Processes For Motor Output Formation In Visual Agnosic Patients
Funder
National Health and Medical Research Council
Funding Amount
$199,260.00
Summary
Damage to the temporo-occipito-parietal areas of the brain leads to selective impairment in cognitive activities, including motor control and vision. Impaired higher visual processes necessary for object recognition, with intact primary visual functions, is defined as visual agnosia. Experimental work in this disorder has been confined largely to the perceptual aspects, neglecting the functional (motoric) consequences. In a series of kinematic and perceptual experiments, we will require patients ....Damage to the temporo-occipito-parietal areas of the brain leads to selective impairment in cognitive activities, including motor control and vision. Impaired higher visual processes necessary for object recognition, with intact primary visual functions, is defined as visual agnosia. Experimental work in this disorder has been confined largely to the perceptual aspects, neglecting the functional (motoric) consequences. In a series of kinematic and perceptual experiments, we will require patients with visual agnosia to grasp objects presented in unusual perspectives or variable illumination. The findings will enlarge our knowledge in three ways. First, they will clarify how distributed, but parallel object-recognition processes are coordinated for intended action towards a goal. Little is known about how we adapt our actions to object perception. A tool can be viewed from different angles, or as having different functional uses, but currently we are unable to explain how the mental representation influences the motor output to that tool. By studying a disrupted system, as in visual agnosia, we can speculate about the organisation of the intact system. Second, this project has important implications for new rehabilitative approaches for subjects affected by object recognition disorders. Only if we understand more fully the nature of the poor visuo-motor coordination, can we implement more efficient rehabilitative techniques. Finally, this project will also contribute to the classification of visual agnosia. Although it is commonly agreed that all agnosic patients are different, there is no standard taxonomy for the disorder. An instrument is necessary which represents the basic empirical phenomena, and which provides objective distinctions between different syndromes. Kinematic characterisation of the perceptual and motor control dysfunction in visual agnosia may be the key to open the file of this fascinating yet poorly understood disorder.Read moreRead less
Novel Approaches To Understanding Peripheral Vision In Patients With Central Vision Loss
Funder
National Health and Medical Research Council
Funding Amount
$367,101.00
Summary
The aim of my research is to develop novel interventions that enhance the peripheral vision of patients with central vision loss, and to investigate the neural correlates of visual perception in peripheral vision in typical adults. My research will inform rehabilitation strategies that optimise the visual function of patients with partial blindness, and provide a more thorough understanding of the underlying neural mechanisms that reduce the quality of peripheral vision.
Orientation-specific Contextual Modulation In Human Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$290,413.00
Summary
Context has a strong infuence on our visual perception. We will study patterns of activity in the normal human brain to identify the cortical signature of contextual modulation in vision. The correspondences between patterns of brain activity and visual perception in the normal human brain will provide data against which brain activity in disorders such as schizophrenia and bipolar disorder can be assessed.
The Role Of The Prefrontal Cortex In Working Memory For Visual Motion
Funder
National Health and Medical Research Council
Funding Amount
$359,796.00
Summary
As objects of interest may not always be in one's view, it is important to store information about their spatial locations for future reference. For example, you could reach for a beverage without taking your eyes from this application. While this may be effortless, such tasks are fundamentally complex, requiring spatial information to be coded, stored in memory and retrieved at appropriate times. This proposal examines how interactions between different brain areas allow this to happen.
Functional Interactions Between Primate Cortical Areas In Tasks Involving Attention And Short-term Memory
Funder
National Health and Medical Research Council
Funding Amount
$267,280.00
Summary
To navigate and operate in the cluttered and dynamic sensory world around us, our brains need to be able to attend to specific objects or features in the environment, identify them and also know where they exist at any one instant of time, prior to performing the appropriate action. The attention, memory, decision and motor components involved in this process possibly involve a variety of cortical areas and neuronal operations. The special primate preparation we have developed permits us to eluc ....To navigate and operate in the cluttered and dynamic sensory world around us, our brains need to be able to attend to specific objects or features in the environment, identify them and also know where they exist at any one instant of time, prior to performing the appropriate action. The attention, memory, decision and motor components involved in this process possibly involve a variety of cortical areas and neuronal operations. The special primate preparation we have developed permits us to elucidate at a neuronal level many of these brain mechanisms. By recording neuronal activities in two different cortical areas simultaneously as the monkey performs a memory task that he has been trained on, we will test the following ideas: (1) A cortical region in the dorsal, parietal stream directs spatial attention by gating other visual areas to process only a selected region of the visual world (2) A region in the ventral, temporal stream directs attention to specific features in the visual world by gating earlier cortical areas (3) The parietal cortical areas that mediate intention for action hold the relevant information in working memory till it is forwarded to the more anterior premotor areas. These experiments have the potential to reveal the basic neuronal scheme that underpins functions such as attention, visual recognition and memory, which are impaired in many neurological disorders.Read moreRead less
Functional Connectivity Between Visual Cortical Areas In The Non-human Primate
Funder
National Health and Medical Research Council
Funding Amount
$387,585.00
Summary
Visual information going from the eyes to the brain is processed in different parts of the brain to extract useful information. However, to be able to select what is important from among the vast number of objects in the scene, top-down signals from higher areas need to act on incoming signals in earlier areas. This project aims to identify what sort of neural pathways are involved in this and how it is done at the cellular level.
Neuronal Linking Of Attention, Perception And Action
Funder
National Health and Medical Research Council
Funding Amount
$586,469.00
Summary
We are able to perceive and interact with the environment around us primarily because a filter of attention selects just the objects or features of relevance in the world and helps to make appropriate motor responses. This project will study how attentional networks of the brain operate to link our perception and action. An understanding of this process is fundamental to revealing the underlying pathology in many neurological conditions where attention is impaired.