John Douglas (Doug) Crawford is a Canadian neuroscientist and the Scientific Director of the Connected Minds program. He is a professor at York University where he holds the York Research Chair in Visuomotor Neuroscience and the title of Distinguished Research Professor in Neuroscience.
Crawford grew up in London Ontario, where he attended the University of Western Ontario. He completed his BSc in Physiology & Psychology in 1987, studying electrophysiology with Stanley Caveney and Gordon Mogenson. He then studied three-dimensional eye movements with Tutis Vilis at Western, where he held a Medical Research Council (MRC) Studentship (1989-1992) and earned his PhD in Physiology in 1993. Following that, he spent two years (1993-1994) studying head-unrestrained gaze control as an MRC post-doctoral fellow with Daniel Guitton at the Montreal Neurological Institute. in 1995 he joined York University's Department of Psychology and York Centre for Vision Research in Toronto as an assistant professor, later attaining cross appointments to the department of Biology, School of Kinesiology & Health Sciences, and the Neuroscience Graduate Diploma Program. During this period he held a MRC Faculty Scholarship (1996-2001), Tier II Canada Research Chair (2001-2007) and Tier I Canada Research Chair (2007-2021) [1] and Now York Research Chair. He became an Associate Professor in 1999, Full Professor in 2005, and Distinguished Research Professor in 2013. [2]
Crawford was the founding National Coordinator of the Canadian Action and Perception Network (CAPnet), [3] the founding Canadian director of the Brain in Action International Research Training Program, [4] and the founding coordinator of the York Neuroscience Graduate Diploma Program. [5] He founded York's neurophysiology laboratories, [6] was a founding member of Melvyn A. Goodale's CIHR Group for Action and Perception [7] and founding co-principal investigator for the CIHR Strategic Training Program in Vision Health Research. [7] He Founded the VSS Canadian Vision Social [8] and is a member of the Canadian Brain Research Strategy Neuroscience Leaders Group. [9] He has the distinction of being the principal investigator and founding Scientific Director of two Canada First Research Excellence Fund (CFREF)-funded programs: 'Vision: Science to Applications' (VISTA), [10] (2016-2023) and then 'Connected Minds: Neural and Machine Systems for a Healthy, Just Society' (2023-).
Crawford has supervised over 60 graduate students and post-doctorals, many graduating to successful careers in academia, medicine, and industry. [11] Among his noteworthy former trainees are Pieter Medendorp, Director of the Donders Centre for Cognition in Nijmegen, [12] Julio Martinez-Trujillo, Provincial Endowed Academic Chair in Autism at Western University, [13] Gunnar Blohm, Queens Professor and Founding Co-Director of the International Summer School in Computational Sensory-Motor Neuroscience [14] and Neuromatch Academy, [15] Aarlenne Khan, Canada Research Chair in Vision and Action at Université de Montréal, [16] and Denise Henriques, York Professor and principal investigator of York University's Sensorimotor Control Lab. [17] For these activities Crawford received York University's 2003 Faculty of Graduate Studies Teaching Award [18] and 2019 Post-Doctoral Supervisor of the Year Award. [19]
Crawford's research investigates the neural mechanisms of visuospatial memory and sensorimotor transformations for eye, head, and hand motion. [20] [21] Recurrent themes in his work include 1) the idea that early representations of movement goals are stored in visual coordinates, updated during self-motion, and then transformed into three-dimensional (3D) commands for different body parts, 2) the use of theory-driven, multimodal neuroscience techniques, and 3) the use of 3D measurements and analysis of eye and body orientation. [22] His specific contributions can be grouped into three areas:
Physiology of the Primate Gaze System Crawford and colleagues performed the first recordings of 3D Vestibulo–ocular reflex axes and Listing's law during head rotation, [23] and identified the midbrain neural integrators for holding vertical and torsional orientation of both the eye [24] and head. [25] They used brain stimulation neurophysiological recordings to investigate the role of the superior colliculus [26] and frontal cortex [27] in eye-head coordination and reference frame coding, and track their egocentric [28] and allocentric [29] coding mechanisms through time. They also showed that remembered visual stimuli are continuously updated across the superior colliculus during smooth pursuit eye movements. [30]
Human Vision and Eye Movements Crawford and colleagues showed that ocular dominance reverses for left and right visual stimuli, [31] how Listing's law of two eyes interacts with stereopsis [32] and that optimal integration theory can explain perisaccadic change blindness. [33] His lab has used TMS [34] and neuroimaging [35] to show the roles of occipital, parietal, and frontal cortex in Transsaccadic memory of visual features.
Eye-Hand Coordination During Reach. Crawford and colleagues used psychophysics and fMRI to show that human parietal lobe retains and updates saccade and reach goals in gaze-centered coordinates, [36] [37] fMRI and TMS to map saccade vs. reach function in human posterior parietal cortex, [38] fMRI and MEG [39] to track the visuomotor transformations forr reach, and psychophysics, [40] neuroimaging, [41] to determine how allocentric and egocentric representations are stored and integrated for goal-directed reaches.
Crawford has also collaborated with clinician scientists to investigate how these various sensorimotor mechanisms fail during disorders such as amblyopia, [42] cervical dystonia [43] and optic ataxia. [44]
Crawford has been listed amongst the world's top 2% researchers. [45] In addition to the research fellowships, research chairs and teaching awards cited above, Crawford has received various research awards. In 1993, he was awarded the Governor General's Academic Gold medal [46] for his PhD work with Tutis Vilis. Since then, he has won various research prizes, including the 1995 Polanyi Prize in Physiology/Medicine, [47] an Alfred P Sloan Fellowship, [48] the 2000 Ontario Premier's Research Excellence Award, the 2002 CIFAR Young Explorer Award (awarded to the "top 20 young investigators in Canada"), the 2004 Steacie Prize (awarded to "a scientist or engineer of 40 years of age or less for outstanding scientific research carried out in Canada."), [49] the 2016 Canadian Physiological Society Sarrazin Award, [50] and the 2018 York President's Research Excellence Award. [51]
The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and then reaches the visual cortex. The area of the visual cortex that receives the sensory input from the lateral geniculate nucleus is the primary visual cortex, also known as visual area 1 (V1), Brodmann area 17, or the striate cortex. The extrastriate areas consist of visual areas 2, 3, 4, and 5.
A saccade is a quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction. In contrast, in smooth-pursuit movements, the eyes move smoothly instead of in jumps. The phenomenon can be associated with a shift in frequency of an emitted signal or a movement of a body part or device. Controlled cortically by the frontal eye fields (FEF), or subcortically by the superior colliculus, saccades serve as a mechanism for fixation, rapid eye movement, and the fast phase of optokinetic nystagmus. The word appears to have been coined in the 1880s by French ophthalmologist Émile Javal, who used a mirror on one side of a page to observe eye movement in silent reading, and found that it involves a succession of discontinuous individual movements.
Saccadic masking, also known as (visual) saccadic suppression, is the phenomenon in visual perception where the brain selectively blocks visual processing during eye movements in such a way that neither the motion of the eye nor the gap in visual perception is noticeable to the viewer.
The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus.
The pulvinar nuclei or nuclei of the pulvinar are the nuclei located in the thalamus. As a group they make up the collection called the pulvinar of the thalamus, usually just called the pulvinar.
In neuroanatomy, the superior colliculus is a structure lying on the roof of the mammalian midbrain. In non-mammalian vertebrates, the homologous structure is known as the optic tectum or optic lobe. The adjective form tectal is commonly used for both structures.
Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms to fixate, inspect and track visual objects of interests. A special type of eye movement, rapid eye movement, occurs during REM sleep.
The pars reticulata (SNpr) is a portion of the substantia nigra and is located lateral to the pars compacta. Most of the neurons that project out of the pars reticulata are inhibitory GABAergic neurons.
In the scientific study of vision, smooth pursuit describes a type of eye movement in which the eyes remain fixated on a moving object. It is one of two ways that visual animals can voluntarily shift gaze, the other being saccadic eye movements. Pursuit differs from the vestibulo-ocular reflex, which only occurs during movements of the head and serves to stabilize gaze on a stationary object. Most people are unable to initiate pursuit without a moving visual signal. The pursuit of targets moving with velocities of greater than 30°/s tends to require catch-up saccades. Smooth pursuit is asymmetric: most humans and primates tend to be better at horizontal than vertical smooth pursuit, as defined by their ability to pursue smoothly without making catch-up saccades. Most humans are also better at downward than upward pursuit. Pursuit is modified by ongoing visual feedback.
The frontal eye fields (FEF) are a region located in the frontal cortex, more specifically in Brodmann area 8 or BA8, of the primate brain. In humans, it can be more accurately said to lie in a region around the intersection of the middle frontal gyrus with the precentral gyrus, consisting of a frontal and parietal portion. The FEF is responsible for saccadic eye movements for the purpose of visual field perception and awareness, as well as for voluntary eye movement. The FEF communicates with extraocular muscles indirectly via the paramedian pontine reticular formation. Destruction of the FEF causes deviation of the eyes to the ipsilateral side.
Supplementary eye field (SEF) is the name for the anatomical area of the dorsal medial frontal lobe of the primate cerebral cortex that is indirectly involved in the control of saccadic eye movements. Evidence for a supplementary eye field was first shown by Schlag, and Schlag-Rey. Current research strives to explore the SEF's contribution to visual search and its role in visual salience. The SEF constitutes together with the frontal eye fields (FEF), the intraparietal sulcus (IPS), and the superior colliculus (SC) one of the most important brain areas involved in the generation and control of eye movements, particularly in the direction contralateral to their location. Its precise function is not yet fully known. Neural recordings in the SEF show signals related to both vision and saccades somewhat like the frontal eye fields and superior colliculus, but currently most investigators think that the SEF has a special role in high level aspects of saccade control, like complex spatial transformations, learned transformations, and executive cognitive functions.
Fixation or visual fixation is the maintaining of the gaze on a single location. An animal can exhibit visual fixation if it possess a fovea in the anatomy of their eye. The fovea is typically located at the center of the retina and is the point of clearest vision. The species in which fixational eye movement has been verified thus far include humans, primates, cats, rabbits, turtles, salamanders, and owls. Regular eye movement alternates between saccades and visual fixations, the notable exception being in smooth pursuit, controlled by a different neural substrate that appears to have developed for hunting prey. The term "fixation" can either be used to refer to the point in time and space of focus or the act of fixating. Fixation, in the act of fixating, is the point between any two saccades, during which the eyes are relatively stationary and virtually all visual input occurs. In the absence of retinal jitter, a laboratory condition known as retinal stabilization, perceptions tend to rapidly fade away. To maintain visibility, the nervous system carries out a procedure called fixational eye movement, which continuously stimulates neurons in the early visual areas of the brain responding to transient stimuli. There are three categories of fixational eye movement: microsaccades, ocular drifts, and ocular microtremor. At small amplitudes the boundaries between categories become unclear, particularly between drift and tremor.
The posterior parietal cortex plays an important role in planned movements, spatial reasoning, and attention.
Eye–hand coordination is the coordinated motor control of eye movement with hand movement and the processing of visual input to guide reaching and grasping along with the use of proprioception of the hands to guide the eyes, a modality of multisensory integration. Eye–hand coordination has been studied in activities as diverse as the movement of solid objects such as wooden blocks, archery, sporting performance, music reading, computer gaming, copy-typing, and even tea-making. It is part of the mechanisms of performing everyday tasks; in its absence, most people would not be able to carry out even the simplest of actions such as picking up a book from a table.
Richard Alan Andersen is an American neuroscientist. He is the James G. Boswell Professor of Neuroscience at the California Institute of Technology in Pasadena, California. His research focuses on visual physiology with an emphasis on translational research to humans in the field of neuroprosthetics, brain-computer interfaces, and cortical repair.
Melvyn Alan Goodale FRSC, FRS is a Canadian neuroscientist. He was the founding Director of the Brain and Mind Institute at the University of Western Ontario where he holds the Canada Research Chair in Visual Neuroscience. He holds appointments in the Departments of Psychology, Physiology & Pharmacology, and Ophthalmology at Western. Goodale's research focuses on the neural substrates of visual perception and visuomotor control.
Gain field encoding is a hypothesis about the internal storage and processing of limb motion in the brain. In the motor areas of the brain, there are neurons which collectively have the ability to store information regarding both limb positioning and velocity in relation to both the body (intrinsic) and the individual's external environment (extrinsic). The input from these neurons is taken multiplicatively, forming what is referred to as a gain field. The gain field works as a collection of internal models off of which the body can base its movements. The process of encoding and recalling these models is the basis of muscle memory.
The tectopulvinar pathway and the geniculostriate pathway are the two visual pathways that travel from the retina to the early visual cortical areas. From the optic tract, the tectopulvinar pathway sends neuronal radiations to the superior colliculus in the tectum, then to the lateral posterior-pulvinar thalamic complex. Approximately 10% of retinal ganglion cells project onto the tectopulvinar pathway.
Michael E. Goldberg, also known as Mickey Goldberg, is an American neuroscientist and David Mahoney Professor at Columbia University. He is known for his work on the mechanisms of the mammalian eye in relation to brain activity. He served as president of the Society for Neuroscience from 2009 to 2010.
The corollary discharge theory (CD) of motion perception helps understand how the brain can detect motion through the visual system, even though the body is not moving. When a signal is sent from the motor cortex of the brain to the eye muscles, a copy of that signal is sent through the brain as well. The brain does this in order to distinguish real movements in the visual world from our own body and eye movement. The original signal and copy signal are then believed to be compared somewhere in the brain. Such a structure has not yet been identified, but it is believed to be the Medial Superior Temporal Area (MST). The original signal and copy need to be compared in order to determine if the change in vision was caused by eye movement or movement in the world. If the two signals cancel then no motion is perceived, but if they do not cancel then the residual signal is perceived as motion in the real world. Without a corollary discharge signal, the world would seem to spin around every time the eyes moved. It is important to note that corollary discharge and efference copy are sometimes used synonymously, they were originally coined for much different applications, with corollary discharge being used in a much broader sense.