Brain Imaging and Neuroscience: The Good, The Bad, & The Ugly
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Brain Imaging and Neuroscience: The Good, The Bad, & The Ugly
Covering topics and controversies in Cognitive Neuroscience and Brain Imaging
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Rescooped by Donald J Bolger from Neuroscience_topics
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Functional maps within a single neuron

Functional maps within a single neuron | Brain Imaging and Neuroscience: The Good, The Bad, & The Ugly | Scoop.it

The presence and plasticity of dendritic ion channels are well established. However, the literature is divided on what specific roles these dendritic ion channels play in neuronal information processing, and there is no consensus on why neuronal dendrites should express diverse ion channels with different expression profiles. In this review, we present a case for viewing dendritic information processing through the lens of the sensory map literature, where functional gradients within neurons are considered as maps on the neuronal topograph. Under such a framework, drawing analogies from the sensory map literature, we postulate that the formation of intraneuronal functional maps is driven by the twin objectives of efficiently encoding inputs that impinge along different dendritic locations and of retaining homeostasis in the face of changes that are required in the coding process. In arriving at this postulate, we relate intraneuronal map physiology to the vast literature on sensory maps and argue that such a metaphorical association provides a fresh conceptual framework for analyzing and understanding single-neuron information encoding. We also describe instances where the metaphor presents specific directions for research on intraneuronal maps, derived from analogous pursuits in the sensory map literature. We suggest that this perspective offers a thesis for why neurons should express and alter ion channels in their dendrites and provides a framework under which active dendrites could be related to neural coding, learning theory, and homeostasis. by Narayanan R & Johnston D, Journal of Neurophysioly, November 1, 2012 vol. 108 no. 9 2343-2351


Via Julien Hering, PhD
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Rescooped by Donald J Bolger from Neuroscience and Psychology
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Sleep Oscillations in the Thalamocortical System Induce Long-Term Neuronal Plasticity

Sleep Oscillations in the Thalamocortical System Induce Long-Term Neuronal Plasticity | Brain Imaging and Neuroscience: The Good, The Bad, & The Ugly | Scoop.it

Highlights

Slow-wave sleep induces long-term potentiation of evoked responses In vitro, stimulation mimicking SWS replicated these results Potentiation of responses was postsynaptic, Ca2+, AMPA, and NMDA dependent The mechanism of potentiation was compatible with the classical LTP mechanism

Summary

Long-term plasticity contributes to memory formation and sleep plays a critical role in memory consolidation. However, it is unclear whether sleep slow oscillation by itself induces long-term plasticity that contributes to memory retention. Using in vivo prethalamic electrical stimulation at 1 Hz, which itself does not induce immediate potentiation of evoked responses, we investigated how the cortical evoked response was modulated by different states of vigilance. We found that somatosensory evoked potentials during wake were enhanced after a slow-wave sleep episode (with or without stimulation during sleep) as compared to a previous wake episode. In vitro, we determined that this enhancement has a postsynaptic mechanism that is calcium dependent, requires hyperpolarization periods (slow waves), and requires a coactivation of both AMPA and NMDA receptors. Our results suggest that long-term potentiation occurs during slow-wave sleep, supporting its contribution to memory.

Sylvain Chauvette, Josée Seigneur, Igor Timofeev, Neuron, Volume 75, Issue 6, 1105-1113, 20 September 2012


Via Julien Hering, PhD, Eudaimonia
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