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Kristin K Baldwin - One of the best experts on this subject based on the ideXlab platform.
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Sensory Maps in the olfactory cortex defined by long range viral tracing of single neurons
Nature, 2011Co-Authors: Sulagna Ghosh, Stephen D Larson, Hooman Hefzi, Zachary Marnoy, Tyler Cutforth, Kartheek Dokka, Kristin K BaldwinAbstract:Sensory information may be represented in the brain by stereotyped mapping of axonal inputs or by patterning that varies between individuals. In olfaction, a stereotyped map is evident in the first Sensory processing centre, the olfactory bulb (OB), where different odours elicit activity in unique combinatorial patterns of spatially invariant glomeruli. Activation of each glomerulus is relayed to higher cortical processing centres by a set of ∼20-50 'homotypic' mitral and tufted (MT) neurons. In the cortex, target neurons integrate information from multiple glomeruli to detect distinct features of chemically diverse odours. How this is accomplished remains unclear, perhaps because the cortical mapping of glomerular information by individual MT neurons has not been described. Here we use new viral tracing and three-dimensional brain reconstruction methods to compare the cortical projections of defined sets of MT neurons. We show that the gross-scale organization of the OB is preserved in the patterns of axonal projections to one processing centre yet reordered in another, suggesting that distinct coding strategies may operate in different targets. However, at the level of individual neurons neither glomerular order nor stereotypy is preserved in either region. Rather, homotypic MT neurons from the same glomerulus innervate broad regions that differ between individuals. Strikingly, even in the same animal, MT neurons exhibit extensive diversity in wiring; axons of homotypic MT pairs diverge from each other, emit primary branches at distinct locations and 70-90% of branches of homotypic and heterotypic pairs are non-overlapping. This pronounced reorganization of Sensory Maps in the cortex offers an anatomic substrate for expanded combinatorial integration of information from spatially distinct glomeruli and predicts an unanticipated role for diversification of otherwise similar output neurons.
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Sensory Maps in the olfactory cortex defined by long range viral tracing of single neurons
Nature, 2011Co-Authors: Sulagna Ghosh, Stephen D Larson, Hooman Hefzi, Zachary Marnoy, Tyler Cutforth, Kartheek Dokka, Kristin K BaldwinAbstract:In the mouse, glomeruli in the olfactory bulb receive projections from single classes of olfactory neurons, thereby forming an odour map. Information from the glomeruli is then relayed to the cortex but the projection patterns from individual glomeruli are not known. Three papers now examine the details of this projection. Luo and colleagues use a combination of genetics and retrograde mono-trans-synaptic rabies virus labelling. They trace the presynaptic connections of individual cortical neurons and find no evidence of connections supporting a stereotyped odour map in the cortex, but see systematic topographical differences in amygdala connectivity. The lack of stereotypical cortical projection is corroborated, both at the level of bulk axonal patterning and in projections of individually labelled neurons, by two papers — one from the Axel laboratory, and one from the Baldwin laboratory — that examine the anterograde projections from individual glomeruli. Together, these findings provide anatomical evidence for combinatorial processing of information from diverse glomeruli by cortical neurons and may also reflect different functions of various areas in mediating innate or learned odour preferences. Sensory information may be represented in the brain by stereotyped mapping of axonal inputs or by patterning that varies between individuals. In olfaction, a stereotyped map is evident in the first Sensory processing centre, the olfactory bulb (OB), where different odours elicit activity in unique combinatorial patterns of spatially invariant glomeruli1,2. Activation of each glomerulus is relayed to higher cortical processing centres by a set of ∼20–50 ‘homotypic’ mitral and tufted (MT) neurons3. In the cortex, target neurons integrate information from multiple glomeruli to detect distinct features of chemically diverse odours4,5,6. How this is accomplished remains unclear, perhaps because the cortical mapping of glomerular information by individual MT neurons has not been described. Here we use new viral tracing and three-dimensional brain reconstruction methods to compare the cortical projections of defined sets of MT neurons. We show that the gross-scale organization of the OB is preserved in the patterns of axonal projections to one processing centre yet reordered in another, suggesting that distinct coding strategies may operate in different targets. However, at the level of individual neurons neither glomerular order nor stereotypy is preserved in either region. Rather, homotypic MT neurons from the same glomerulus innervate broad regions that differ between individuals. Strikingly, even in the same animal, MT neurons exhibit extensive diversity in wiring; axons of homotypic MT pairs diverge from each other, emit primary branches at distinct locations and 70–90% of branches of homotypic and heterotypic pairs are non-overlapping. This pronounced reorganization of Sensory Maps in the cortex offers an anatomic substrate for expanded combinatorial integration of information from spatially distinct glomeruli and predicts an unanticipated role for diversification of otherwise similar output neurons.
Adrian Rees - One of the best experts on this subject based on the ideXlab platform.
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Sensory Maps: Aligning Maps of visual and auditory space
Current biology : CB, 1996Co-Authors: Adrian ReesAbstract:Visual and auditory space are represented topographically in the superior colliculus in the midbrain. Recent experiments show that N-methyl-D-aspartate (NMDA) receptors play an important role in aligning auditory and visual Maps during development.
Stephanie M. Warder - One of the best experts on this subject based on the ideXlab platform.
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Sensory integration in the deep layers of superior colliculus.
Progress in brain research, 1993Co-Authors: Carol K. Peck, John A. Baro, Stephanie M. WarderAbstract:Publisher Summary The intermediate and deep layers of the superior colliculus appear to be critical parts of the neural circuits involved in the location of visual targets in extra personal space. Many neurons in these layers respond not only to visual input but also to input from other Sensory systems - in particular, t6 auditory and somatoSensory inputs, and also discharge prior to saccadic eye movements. Neuronal responses to auditory and visual targets, presented either together or separately, in alert, trained cats are studied. When the eyes are centered in the orbit, simultaneous visual and auditory stimulation at the same location in space produces substantial facilitation in the majority of intermediate and deep layer neurons. When the eyes are deviated in the orbit, the borders of some but not all, auditory receptive fields shift in the direction of the deviating eye movement. Among neurons responsive to both visual and auditory input, visual receptive fields shift more substantially than do auditory receptive fields. Deviation of the eyes does not affect the animal's ability to locate either visual or auditory targets. These results imply that Sensory Maps are actively transformed by the movements of organisms.
Sulagna Ghosh - One of the best experts on this subject based on the ideXlab platform.
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Sensory Maps in the olfactory cortex defined by long range viral tracing of single neurons
Nature, 2011Co-Authors: Sulagna Ghosh, Stephen D Larson, Hooman Hefzi, Zachary Marnoy, Tyler Cutforth, Kartheek Dokka, Kristin K BaldwinAbstract:Sensory information may be represented in the brain by stereotyped mapping of axonal inputs or by patterning that varies between individuals. In olfaction, a stereotyped map is evident in the first Sensory processing centre, the olfactory bulb (OB), where different odours elicit activity in unique combinatorial patterns of spatially invariant glomeruli. Activation of each glomerulus is relayed to higher cortical processing centres by a set of ∼20-50 'homotypic' mitral and tufted (MT) neurons. In the cortex, target neurons integrate information from multiple glomeruli to detect distinct features of chemically diverse odours. How this is accomplished remains unclear, perhaps because the cortical mapping of glomerular information by individual MT neurons has not been described. Here we use new viral tracing and three-dimensional brain reconstruction methods to compare the cortical projections of defined sets of MT neurons. We show that the gross-scale organization of the OB is preserved in the patterns of axonal projections to one processing centre yet reordered in another, suggesting that distinct coding strategies may operate in different targets. However, at the level of individual neurons neither glomerular order nor stereotypy is preserved in either region. Rather, homotypic MT neurons from the same glomerulus innervate broad regions that differ between individuals. Strikingly, even in the same animal, MT neurons exhibit extensive diversity in wiring; axons of homotypic MT pairs diverge from each other, emit primary branches at distinct locations and 70-90% of branches of homotypic and heterotypic pairs are non-overlapping. This pronounced reorganization of Sensory Maps in the cortex offers an anatomic substrate for expanded combinatorial integration of information from spatially distinct glomeruli and predicts an unanticipated role for diversification of otherwise similar output neurons.
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Sensory Maps in the olfactory cortex defined by long range viral tracing of single neurons
Nature, 2011Co-Authors: Sulagna Ghosh, Stephen D Larson, Hooman Hefzi, Zachary Marnoy, Tyler Cutforth, Kartheek Dokka, Kristin K BaldwinAbstract:In the mouse, glomeruli in the olfactory bulb receive projections from single classes of olfactory neurons, thereby forming an odour map. Information from the glomeruli is then relayed to the cortex but the projection patterns from individual glomeruli are not known. Three papers now examine the details of this projection. Luo and colleagues use a combination of genetics and retrograde mono-trans-synaptic rabies virus labelling. They trace the presynaptic connections of individual cortical neurons and find no evidence of connections supporting a stereotyped odour map in the cortex, but see systematic topographical differences in amygdala connectivity. The lack of stereotypical cortical projection is corroborated, both at the level of bulk axonal patterning and in projections of individually labelled neurons, by two papers — one from the Axel laboratory, and one from the Baldwin laboratory — that examine the anterograde projections from individual glomeruli. Together, these findings provide anatomical evidence for combinatorial processing of information from diverse glomeruli by cortical neurons and may also reflect different functions of various areas in mediating innate or learned odour preferences. Sensory information may be represented in the brain by stereotyped mapping of axonal inputs or by patterning that varies between individuals. In olfaction, a stereotyped map is evident in the first Sensory processing centre, the olfactory bulb (OB), where different odours elicit activity in unique combinatorial patterns of spatially invariant glomeruli1,2. Activation of each glomerulus is relayed to higher cortical processing centres by a set of ∼20–50 ‘homotypic’ mitral and tufted (MT) neurons3. In the cortex, target neurons integrate information from multiple glomeruli to detect distinct features of chemically diverse odours4,5,6. How this is accomplished remains unclear, perhaps because the cortical mapping of glomerular information by individual MT neurons has not been described. Here we use new viral tracing and three-dimensional brain reconstruction methods to compare the cortical projections of defined sets of MT neurons. We show that the gross-scale organization of the OB is preserved in the patterns of axonal projections to one processing centre yet reordered in another, suggesting that distinct coding strategies may operate in different targets. However, at the level of individual neurons neither glomerular order nor stereotypy is preserved in either region. Rather, homotypic MT neurons from the same glomerulus innervate broad regions that differ between individuals. Strikingly, even in the same animal, MT neurons exhibit extensive diversity in wiring; axons of homotypic MT pairs diverge from each other, emit primary branches at distinct locations and 70–90% of branches of homotypic and heterotypic pairs are non-overlapping. This pronounced reorganization of Sensory Maps in the cortex offers an anatomic substrate for expanded combinatorial integration of information from spatially distinct glomeruli and predicts an unanticipated role for diversification of otherwise similar output neurons.
Timothy H Murphy - One of the best experts on this subject based on the ideXlab platform.
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displacement of Sensory Maps and disorganization of motor cortex after targeted stroke in mice
Stroke, 2013Co-Authors: Thomas C Harrison, Gergely Silasi, Jamie D Boyd, Timothy H MurphyAbstract:Background and Purpose—Recovery from stroke is hypothesized to involve the reorganization of surviving cortical areas. To study the functional organization of sensorimotor cortex at multiple time points before and after stroke, we performed longitudinal light-based motor mapping of transgenic mice expressing light-sensitive channelrhodopsin-2 in layer 5 cortical neurons. Methods—Pulses of light stimulation were targeted to an array of cortical points, whereas evoked forelimb motor activity was recorded using noninvasive motion sensors. Intrinsic optical signal imaging produced Maps of the forelimb somatoSensory cortex. The resulting motor and Sensory Maps were repeatedly generated for weeks before and after small (0.2 mm3) photothrombotic infarcts were targeted to forelimb motor or Sensory cortex. Results—Infarcts targeted to forelimb Sensory or motor areas caused decreased motor output in the infarct area and spatial displacement of Sensory and motor Maps. Strokes in Sensory cortex caused the Sensory map...
