Space-time representation in the brain. The cerebellum as a predictive space-time metric tensor

Pellionisz, A.

doi:10.1016/0306-4522(82)90224-x

Cited by 387 publications

(46 citation statements)

References 16 publications

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“…In other words, the anatomo-functional architecture of the visual system leads to the situation where a visual event, even discrete (like a single static spot), undergoes a spatiotemporal blurring (Pellionisz and Llinás, 1982) while the activity it evokes on the retina propagates toward the motor centers and muscles. In fact, the snapshot likely corresponds to activities that are spatially and temporally distributed across several regions in the brain.…”

Section: Discussionmentioning

confidence: 99%

“…This performance is impressive when one considers the distributed nature of signals that encode an object in the brain. Indeed, before the target-evoked retinal activity leads to the recruitment of appropriate muscles, the diverging projections within the visual system and the transmissions of signals through multiple relays with diverse conduction velocities and integration times (Pellionisz and Llinás, 1982;Nowak and Bullier, 1997;Schmolesky et al, 1998) lead to neural signals that are spatially and temporally distributed across several brain regions. Yet the common observation that animals are able to intercept an object at the right place and time suggests that the brain can somehow estimate its current spatiotemporal coordinates (hic et nunc).…”

Section: Introductionmentioning

confidence: 99%

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Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Filippi¹,

Goffart²

2012

J. Neurosci.

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Animals can make saccadic eye movements to intercept a moving object at the right place and time. Such interceptive saccades indicate that, despite variable sensorimotor delays, the brain is able to estimate the current spatiotemporal (hic et nunc) coordinates of a target at saccade end. The present work further tests the robustness of this estimate in the monkey when a change in eye position and a delay are experimentally added before the onset of the saccade and in the absence of visual feedback. These perturbations are induced by brief microstimulation in the deep superior colliculus (dSC). When the microstimulation moves the eyes in the direction opposite to the target motion, a correction saccade brings gaze back on the target path or very near. When it moves the eye in the same direction, the performance is more variable and depends on the stimulated sites. Saccades fall ahead of the target with an error that increases when the stimulation is applied more caudally in the dSC. The numerous cases of compensation indicate that the brain is able to maintain an accurate and robust estimate of the location of the moving target. The inaccuracies observed when stimulating the dSC that encodes the visual field traversed by the target indicate that dSC microstimulation can interfere with signals encoding the target motion path. The results are discussed within the framework of the dual-drive and the remapping hypotheses.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Filippi¹,

Goffart²

2012

J. Neurosci.

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“…The neural architecture is highly interconnected. Neurons such as Purkinje cells may have upwards of 80,000 input connections, and neurons in cerebral cortex can have upwards of 10,000 output connections (Anderson and Hinton 1981, Pellionisz and Llinas 1982, Sejnowski 1986). …”

Section: Is Cognition Mainly Symbol Manipulation In the Language Of Tmentioning

confidence: 99%

Neural Representation and Neural Computation

Churchland¹,

Sejnowski²

1990

Philosophical Perspectives

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“…Although many studies have indicated that LTP is due to an increased effectiveness of monosynaptic connections [1, 11], the possibility that alterations in the activity of excitatory local circuit neurons can also underlie changes in synaptic efficacy has been raised [20]. Recent interest in neural networks as devices for information storage and retrieval [14,19] suggests that interactions between local mosaics of neurons may be important in learning and memory as well as changes in monosynaptic connections. This is especially relevant in the neocortex where 70% of fibers forming asymmetric synapses arise from intrinsic neurons involved in local excitatory circuits [15].…”

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confidence: 99%

Long-term potentiation in frontal cortex: Role of NMDA-modulated polysynaptic excitatory pathways

Sutor

Hablitz

1989

Neuroscience Letters

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The present study examined the role of N-methyl-l)-aspartic acid (NMDA) receptors in synaptic plasticity in regular-spiking cells of rat frontal cortex, lntracortical stimulation, at levels subthreshold for eliciration of action potentials, evoked a late excitatory postsynaptic potential (EPSP) in layer II II1 neurons that was sensitive to the selective NMDA antagonist D-2-amino-5-phosphonovaleric acid (APV). This late EPSP showed marked short-term frequency-dependent depression, suggesting that it is polysynaptic in origin. Polysynaptic late EPSPs were selectively enhanced following high-frequency stimulation. This sustained increase in synaptic efficacy, or long-term potentiation, was expressed in regular spiking cells and appeared to result from activation of NMDA receptors on excitatory interneurons. These data demonstrate the existence of an NMDA-modulated polysynaptic circuit in the neocortcx which displays several types of use-dependent plasticity, Neocortical neurons can display sustained increases in synaptic efficacy following conditioning stimulation [2, 3, 5]. The mechanisms underlying this long-term potentiation (LTP) are unclear. Although many studies have indicated that LTP is due to an increased effectiveness of monosynaptic connections [1, 11], the possibility that alterations in the activity of excitatory local circuit neurons can also underlie changes in synaptic efficacy has been raised [20]. Recent interest in neural networks as devices for information storage and retrieval [14,19] suggests that interactions between local mosaics of neurons may be important in learning and memory as well as changes in monosynaptic connections. This is especially relevant in the neocortex where 70% of fibers forming asymmetric synapses arise from intrinsic neurons involved in local excitatory circuits [15]. In examining synaptic plasticity in the neocortex, we have found a type of LTP that involves selective enhancement of polysynaptic EPSPs.

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Space-time representation in the brain. The cerebellum as a predictive space-time metric tensor

Cited by 387 publications

References 16 publications

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Neural Representation and Neural Computation

Long-term potentiation in frontal cortex: Role of NMDA-modulated polysynaptic excitatory pathways

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