Melvyn A. Goodale - Academia.edu (original) (raw)

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Papers by Melvyn A. Goodale

Brain Research, 2006

It has been suggested that there are two separate visual streams in the human cerebral cortex: a ... more It has been suggested that there are two separate visual streams in the human cerebral cortex: a ventral pathway that provides perceptual representations of the world and serves as a platform for cognitive operations, and a dorsal pathway that transforms visual information for the control of motor acts. Evidence for this distinction comes from neuropsychology, neuroimaging, and neurophysiology. There is also evidence from experimental psychology, with normal observers experiencing an illusion-where perception and action can be dissociated, although much of this evidence is controversial.

Journal of neurophysiology, 2014

We do not always perceive the sequence of events as they actually unfold. For example, when two e... more We do not always perceive the sequence of events as they actually unfold. For example, when two events occur before a rapid eye movement (saccade), the interval between them is often perceived as shorter than it really is and the order of those events can be sometimes reversed (Morrone MC, Ross J, Burr DC. Nat Neurosci 8: 950-954, 2005). In the present article we show that these misperceptions of the temporal order of events critically depend on whether the saccade is reflexive or voluntary. In the first experiment, participants judged the temporal order of two visual stimuli that were presented one after the other just before a reflexive or voluntary saccadic eye movement. In the reflexive saccade condition, participants moved their eyes to a target that suddenly appeared. In the voluntary saccade condition, participants moved their eyes to a target that was present already. Similarly to the above-cited study, we found that the temporal order of events was often misjudged just before a reflexive saccade to a suddenly appearing target. However, when people made a voluntary saccade to a target that was already present, there was a significant reduction in the probability of misjudging the temporal order of the same events. In the second experiment, the reduction was seen in a memory-delay task. It is likely that the nature of the motor command and its origin determine how time is perceived during the moments preceding the motor act.

Consciousness and Cognition

Some critics of the two-visual-systems hypothesis (TVSH) argue that it is incompatible with the f... more Some critics of the two-visual-systems hypothesis (TVSH) argue that it is incompatible with the fundamentally egocentric nature of visual experience (what we call the ‘perspectival account’). The TVSH proposes that the ventral stream, which delivers up our visual experience of the world, works in an allocentric frame of reference, whereas the dorsal stream, which mediates the visual control of action, uses egocentric frames of reference. Given that the TVSH is also committed to the claim that dorsal-stream processing does not contribute to the contents of visual experience, it has been argued that the TVSH cannot account for the egocentric features of our visual experience. This argument, however, rests on a misunderstanding about how the operations mediating action and the operations mediating perception are specified in the TVSH. In this article, we emphasize the importance of the ‘outputs’ of the two-systems to the specification of their respective operations. We argue that once this point is appreciated, it becomes evident that the TVSH is entirely compatible with a perspectival account of visual experience.

Journal of Vision, 2010

We recently reported bilateral face-preferential activation in the middle fusiform gyrus (mFG) an... more We recently reported bilateral face-preferential activation in the middle fusiform gyrus (mFG) and in the superior temporal sulcus (STS) of patient DF, who has severe acquired prosopagnosia and object agnosia but who is able to discriminate a face from an object (Steeves et al., ...

Experimental Brain Research, 2011

When we reach out to grasp objects, vision plays a major role in the control of our movements. Ne... more When we reach out to grasp objects, vision plays a major role in the control of our movements. Nevertheless, other sensory modalities contribute to the fine-tuning of our actions. Even olfaction has been shown to play a role in the scaling of movements directed at objects. Much less is known about how auditory information might be used to program grasping movements. The aim of our study was to investigate how the sound of a target object affects the planning of grasping movements in normal right-handed subjects. We performed an experiment in which auditory information could be used to infer size of targets when the availability of visual information was varied from trial to trial. Classical kinematic parameters (such as grip aperture) were measured to evaluate the influence of auditory information. In addition, an optimal inference modeling was applied to the data. The scaling of grip aperture indicated that the introduction of sound allowed subjects to infer the size of the object when vision was not available. Moreover, auditory information affected grip aperture even when vision was available. Our findings suggest that the differences in the natural impact sounds of objects of different sizes being placed on a surface can be used to plan grasping movements.

We recorded muscle activity from an upper limb muscle while human subjects reached towards periph... more We recorded muscle activity from an upper limb muscle while human subjects reached towards peripheral targets. We tested the hypothesis that the transient visual response sweeps not only through the central nervous system, but also through the peripheral nervous system. Like the transient visual response in the central nervous system, stimulus-locked muscle responses (< 100 ms) were sensitive to stimulus contrast, and were temporally and spatially dissociable from voluntary orienting activity. Also, the arrival of visual responses reduced the variability of muscle activity by resetting the phase of ongoing low-frequency oscillations. This lat- ter finding critically extends the emerging evidence that the feedforward visual sweep reduces neural variability via phase reset- ting. We conclude that, when sensory information is relevant to a particular effector, detailed information about the sensorimotor transformation, even from the earliest stages, is found in the peripheral nervous system.

Neuropsychologia, 2006