C. Blakemore - Academia.edu (original) (raw)
Papers by C. Blakemore
Science China Life Sciences
Amblyopia resulting from early deprivation of vision or defocus in one eye reflects an imbalance ... more Amblyopia resulting from early deprivation of vision or defocus in one eye reflects an imbalance of input from the eyes to the visual cortex. We tested the hypothesis that asynchronous stimulation of the two eyes might induce synaptic plasticity and rebalance input. Experiments on normal adults showed that repetitive brief exposure of grating stimuli, with the onset of each stimulus delayed by 8.3 ms in one eye, results in a shift in perceptual eye dominance. Clinical studies (Clinical trial registration number: ChiCTR2100049130), using popular 3D movies with similar asynchrony between the two eyes (amblyopic eye stimulated first) to treat anisometropic amblyopia, established that just 10.5 h of conditioning over <3 weeks produced improvement that met criteria for successful treatment. The benefits of asynchronous conditioning accumulate over 20-30 45 min sessions, and are maintained for at least 2 years. Finally, we demonstrate that asynchronous binocular treatment alone is more effective than patching only. This novel treatment is popular with children and is some 50 times more efficient than patching alone.
The Journal of physiology, 1974
About half a century ago, the first micro–electrode recordings of sensory neurons in mammalian vi... more About half a century ago, the first micro–electrode recordings of sensory neurons in mammalian visual cortex transformed our thinking about how vision works. Since that time, the physiology of cognitive processes has developed into a mature and complete discipline. New techniques have been developed and the old techniques are being deployed in new ways. However, the most spectacular development has been the growth in the range of topics that are now addressed by this discipline.
Novartis Foundation Symposia
In advanced mammals the visual system consists of a number of parallel channels for the efficient... more In advanced mammals the visual system consists of a number of parallel channels for the efficient processing of different aspects of the visual scene. Much of the basic anatomical structure of the visual pathway is constructed before birth. A wave of maturation sweeps through the system, from the eye to the visual cortex, the correct formation of connections depending on precisely timed interactions between axons and their targets. Competition between growing axons (apparently dependent on spontaneous impulse activity in those axons), cell death (partly influenced by competition between those cells' axons), axon withdrawal, trophic interactions--these and other mechanisms play a part in constructing the visual pathway and laying down basic 'maps' of the visual field before birth. Disturbances in such processes might underlie disorders of the genesis of the nervous system. At the level of the visual cortex, synaptic plasticity continues after birth and may permit cortical neurons to refine their processing capacities on the basis of information provided by the visual environment. This makes the young animal vulnerable to disturbances of visual experience early in life, which can cause virtually irreversible deficits in stereoscopic vision, visual resolution and sensitivity to contrast (amblyopia) in adult life.
The Journal of Neuroscience
The Journal of Neuroscience
The Journal of Neuroscience
Nature Neuroscience
During development of the cerebral cortex, the invasion of thalamic axons and subsequent differen... more During development of the cerebral cortex, the invasion of thalamic axons and subsequent differentiation of cortical neurons are tightly coordinated. Here we provide evidence that glutamate neurotransmission triggers a critical signaling mechanism involving the activation of phospholipase C-β1 (PLC-β1) by metabotropic glutamate receptors (mGluRs). Homozygous null mutation of either PLC-β1 or mGluR5 dramatically disrupts the cytoarchitectural differentiation of 'barrels' in the mouse somatosensory cortex, despite segregation in the pattern of thalamic innervation. Furthermore, group 1 mGluR-stimulated phosphoinositide hydrolysis is dramatically reduced in PLC-β1-/mice during barrel development. Our data indicate that PLC-β1 activation via mGluR5 is critical for the coordinated development of the neocortex, and that presynaptic and postsynaptic components of cortical differentiation can be genetically dissociated.
The Journal of Physiology
The Journal of Physiology
S'UMMARY 1. Binocularly driven units were investigated in the cat's primary visual cortex.
The Journal of Physiology
The Journal of Physiology, 1986
Ciba Foundation symposium, 1979
The Journal of physiology, 1974
Zoltan Molnar, John Mitrofanis* and Colin Blakemore University Laboratory of Physiology, Parks Ro... more Zoltan Molnar, John Mitrofanis* and Colin Blakemore University Laboratory of Physiology, Parks Road, Oxford OXI 3PT and *Department of Human Anatomy, South Parks Road, Oxford OXI 3QX In view of the fact that the intercellular messenger nitric oxide (NO) activates intracellular pathways that could regulate neuronal growth and death, synaptogenesis and synaptic strength (Vincent & Hope, 1992), we studied the distribution of cells capable of producing NO in the developing rat cortex. Rat fetuses, removed under pentobarbitone anaesthesia (100 mg kg-' I.P. to the pregnant female) on post-conceptual day 14-21, and pups of various postnatal (P) ages (PO-P24 and adult), anaesthetized with an I.P. overdose of pentobarbitone, were transcardially perfused with 4 % paraformaldehyde in 0.1 M phosphate buffer (pH 7.4). The brains were removed, postfixed for 1-2 h, dehydrated in 30 % sucrose in phosphate-buffered saline, frozen and cut coronally or horizontally at 50-75 pm. Sections were processed histochemically (Mitrofanis, 1989) to reveal nicotinamide adenine dinucleotide phosphatediaphorase (NADPH-d), which is the synthase of NO. We used a camera lucida to plot the areal and laminar distribution of the characteristic blue-stained cells. Heavily stained (Golgi-like) polymorphous neurons first appear at the time of birth, scattered sparsely in the lowest part of the cortical plate and the adjacent subplate (but not in layer 1, even though its cells are generated at the same time as the subplate). During the first postnatal week, NADPH-d expression, in multiform and bipolar or bistellate neurons, moves up progressively through the cortical layers. By the end of the first week, the processes of NADPH-d cells form a dense fibre network throughout the cortex, extending from the white matter to the upper layers. During this period of early postnatal development (P0-P7), the emergence of NADPH-d reactivity is more advanced in rostrolateral than caudomedial cortex, reflecting the temporal gradient of maturation across the hemisphere. No pyramidal cells are labelled at any age. By P13 the overall density of stained polymorphous, bipolar and bistellate cells is somewhat reduced in all layers (compared to P7), but the dense fibre network increases in clarity. At P24 the adult distribution of NADPH-d-positive cells and processes is achieved. Through the elaborate fibre meshwork, present in all areas in all layers including the white matter, the population of NO cells is in a strategic position to influence the entire cortex during the major phase of dendritic maturation, synaptogenesis, cell death and synaptic plasticity.
Science China Life Sciences
Amblyopia resulting from early deprivation of vision or defocus in one eye reflects an imbalance ... more Amblyopia resulting from early deprivation of vision or defocus in one eye reflects an imbalance of input from the eyes to the visual cortex. We tested the hypothesis that asynchronous stimulation of the two eyes might induce synaptic plasticity and rebalance input. Experiments on normal adults showed that repetitive brief exposure of grating stimuli, with the onset of each stimulus delayed by 8.3 ms in one eye, results in a shift in perceptual eye dominance. Clinical studies (Clinical trial registration number: ChiCTR2100049130), using popular 3D movies with similar asynchrony between the two eyes (amblyopic eye stimulated first) to treat anisometropic amblyopia, established that just 10.5 h of conditioning over <3 weeks produced improvement that met criteria for successful treatment. The benefits of asynchronous conditioning accumulate over 20-30 45 min sessions, and are maintained for at least 2 years. Finally, we demonstrate that asynchronous binocular treatment alone is more effective than patching only. This novel treatment is popular with children and is some 50 times more efficient than patching alone.
The Journal of physiology, 1974
About half a century ago, the first micro–electrode recordings of sensory neurons in mammalian vi... more About half a century ago, the first micro–electrode recordings of sensory neurons in mammalian visual cortex transformed our thinking about how vision works. Since that time, the physiology of cognitive processes has developed into a mature and complete discipline. New techniques have been developed and the old techniques are being deployed in new ways. However, the most spectacular development has been the growth in the range of topics that are now addressed by this discipline.
Novartis Foundation Symposia
In advanced mammals the visual system consists of a number of parallel channels for the efficient... more In advanced mammals the visual system consists of a number of parallel channels for the efficient processing of different aspects of the visual scene. Much of the basic anatomical structure of the visual pathway is constructed before birth. A wave of maturation sweeps through the system, from the eye to the visual cortex, the correct formation of connections depending on precisely timed interactions between axons and their targets. Competition between growing axons (apparently dependent on spontaneous impulse activity in those axons), cell death (partly influenced by competition between those cells' axons), axon withdrawal, trophic interactions--these and other mechanisms play a part in constructing the visual pathway and laying down basic 'maps' of the visual field before birth. Disturbances in such processes might underlie disorders of the genesis of the nervous system. At the level of the visual cortex, synaptic plasticity continues after birth and may permit cortical neurons to refine their processing capacities on the basis of information provided by the visual environment. This makes the young animal vulnerable to disturbances of visual experience early in life, which can cause virtually irreversible deficits in stereoscopic vision, visual resolution and sensitivity to contrast (amblyopia) in adult life.
The Journal of Neuroscience
The Journal of Neuroscience
The Journal of Neuroscience
Nature Neuroscience
During development of the cerebral cortex, the invasion of thalamic axons and subsequent differen... more During development of the cerebral cortex, the invasion of thalamic axons and subsequent differentiation of cortical neurons are tightly coordinated. Here we provide evidence that glutamate neurotransmission triggers a critical signaling mechanism involving the activation of phospholipase C-β1 (PLC-β1) by metabotropic glutamate receptors (mGluRs). Homozygous null mutation of either PLC-β1 or mGluR5 dramatically disrupts the cytoarchitectural differentiation of 'barrels' in the mouse somatosensory cortex, despite segregation in the pattern of thalamic innervation. Furthermore, group 1 mGluR-stimulated phosphoinositide hydrolysis is dramatically reduced in PLC-β1-/mice during barrel development. Our data indicate that PLC-β1 activation via mGluR5 is critical for the coordinated development of the neocortex, and that presynaptic and postsynaptic components of cortical differentiation can be genetically dissociated.
The Journal of Physiology
The Journal of Physiology
S'UMMARY 1. Binocularly driven units were investigated in the cat's primary visual cortex.
The Journal of Physiology
The Journal of Physiology, 1986
Ciba Foundation symposium, 1979
The Journal of physiology, 1974
Zoltan Molnar, John Mitrofanis* and Colin Blakemore University Laboratory of Physiology, Parks Ro... more Zoltan Molnar, John Mitrofanis* and Colin Blakemore University Laboratory of Physiology, Parks Road, Oxford OXI 3PT and *Department of Human Anatomy, South Parks Road, Oxford OXI 3QX In view of the fact that the intercellular messenger nitric oxide (NO) activates intracellular pathways that could regulate neuronal growth and death, synaptogenesis and synaptic strength (Vincent & Hope, 1992), we studied the distribution of cells capable of producing NO in the developing rat cortex. Rat fetuses, removed under pentobarbitone anaesthesia (100 mg kg-' I.P. to the pregnant female) on post-conceptual day 14-21, and pups of various postnatal (P) ages (PO-P24 and adult), anaesthetized with an I.P. overdose of pentobarbitone, were transcardially perfused with 4 % paraformaldehyde in 0.1 M phosphate buffer (pH 7.4). The brains were removed, postfixed for 1-2 h, dehydrated in 30 % sucrose in phosphate-buffered saline, frozen and cut coronally or horizontally at 50-75 pm. Sections were processed histochemically (Mitrofanis, 1989) to reveal nicotinamide adenine dinucleotide phosphatediaphorase (NADPH-d), which is the synthase of NO. We used a camera lucida to plot the areal and laminar distribution of the characteristic blue-stained cells. Heavily stained (Golgi-like) polymorphous neurons first appear at the time of birth, scattered sparsely in the lowest part of the cortical plate and the adjacent subplate (but not in layer 1, even though its cells are generated at the same time as the subplate). During the first postnatal week, NADPH-d expression, in multiform and bipolar or bistellate neurons, moves up progressively through the cortical layers. By the end of the first week, the processes of NADPH-d cells form a dense fibre network throughout the cortex, extending from the white matter to the upper layers. During this period of early postnatal development (P0-P7), the emergence of NADPH-d reactivity is more advanced in rostrolateral than caudomedial cortex, reflecting the temporal gradient of maturation across the hemisphere. No pyramidal cells are labelled at any age. By P13 the overall density of stained polymorphous, bipolar and bistellate cells is somewhat reduced in all layers (compared to P7), but the dense fibre network increases in clarity. At P24 the adult distribution of NADPH-d-positive cells and processes is achieved. Through the elaborate fibre meshwork, present in all areas in all layers including the white matter, the population of NO cells is in a strategic position to influence the entire cortex during the major phase of dendritic maturation, synaptogenesis, cell death and synaptic plasticity.