Article

Cellular substrates and laminar profile of sleep K-complex

Laboratoire de Neurophysiologie, Faculté de Médecine, Université Laval, Quebec, Canada.
Neuroscience (Impact Factor: 3.36). 03/1998; 82(3):671-86. DOI: 10.1016/S0306-4522(97)00319-9
Source: PubMed

ABSTRACT

We describe the cellular mechanisms that underlie the generation of the K-complex, a major grapho-element of sleep electroencephalogram in humans. First we demonstrate the similarity between K-complexes recorded during natural sleep and under ketamine-xylazine anaesthesia in cats. Thereafter, we show by means of multi-site cellular and field potential recordings that K-complexes are rhythmic at frequencies of less than 1 Hz (mainly 0.5-0.9 Hz) and that they are synchronously distributed over the whole cortical surface as well as transferred to the thalamus. The surface K-complex reverses its polarity at a cortical depth of about 0.3 mm. At the cortical depth, the K-complex is made of a sharp and high-amplitude negative deflection that reflects cellular depolarization, often preceded by a smaller-amplitude, positive slow-wave reflecting cellular hyperpolarization. The sharp component of the K-complex may lead to a spindle sequence and/or to fast (mainly 20-50 Hz) oscillations. K-complexes appear spontaneously or triggered by cortical or thalamic stimulation, and they arise within cortical networks. We suggest that K-complexes, either in isolation or followed by a brief sequence of spindle waves, are the expression of the spontaneously occurring, cortically generated slow oscillation.

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Available from: Florin Amzica, Sep 23, 2014
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    • "An innovative method to enhance slow waves is to use acoustic stimulation. It is well established that auditory tones can influence EEG activity by producing K-complexes, which are similar in structure and are precursors to slow waves (Amzica and Steriade, 1998). Tononi et al. (2010) showed that auditory stimulation during sleep can enhance SWA in young adults. "
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    Full-text · Article · Nov 2015 · Journal of Neuroscience Methods
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    • "Slow waves are local field potential and EEG signatures of cortical network transitions between high and low activity states: a depolarized UP state associated with neuronal spiking and a low-activity DOWN state with little firing or synaptic drive (Steriade et al., 1993a,b). The membrane potentials of pyramidal cells therefore display a characteristic bimodal distribution during slow waves, with the origin of UP/DOWN state transitions focused in the deep layers of the cortex (Amzica & Steriade, 1997b; Sanchez-Vives & McCormick, 2000; Chauvette et al., 2010; Beltramo et al., 2013). "
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    Full-text · Article · Apr 2014 · European Journal of Neuroscience
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    • "In agreement with other experimental studies, our findings show that acoustic stimulation during SWS evokes a specific electrophysiological response, consisting of a strong hyperpolarization after about 500 ms followed by a depolarization, which is maximal at about 900 ms (Amzica and Steriade, 1998; Plihal et al., 1996; Riedner et al., 2011). A strong hyperpolarization followed by a depolarization is characteristic for the SOs that are detected as such by our algorithm. "
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