Coupled slow and delta oscillations between cuneothalamic and thalamocortical neurons in the chloralose anesthetized cat (original) (raw)
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Low-frequency oscillatory activities intrinsic to rat and cat thalamocortical cells
The Journal of physiology, 1991
1. Low-frequency membrane potential oscillations recorded intracellularly from thalamocortical (TC) cells of the rat and cat dorsal lateral geniculate nucleus (dLGN) and of the rat ventrobasal nucleus (VB) maintained in vitro were investigated. On the basis of their electrophysiological and pharmacological properties, four types of activity were distinguished and named: the pacemaker oscillations, the spindle-like oscillations, the 'very slow' oscillations and the 'N-methyl-D-aspartate' (NMDA) oscillations. 2. The pacemaker oscillations (95 out of 173 cells) consisted of rhythmic, large-amplitude (10-30 mV) depolarizations which occurred at a frequency of 1.8 +/- 0.3 Hz (range, 0.5-2.9 Hz) and could often give rise to single or a burst of action potentials. Pacemaker oscillations were observed when the membrane potential was moved negative to -55 and positive to -80 mV, but in a given cell the upper and lower limits of this voltage range were separated by only 13.1 +...
Synchronization of low-frequency rhythms in corticothalamic networks
1997
We have investigated the degree of synchronization between cortical, thalamic reticular and thalamocortical neurons of cats during low-frequency (<15 Hz) sleep-like oscillations, as they appear under anaesthesia. We have also studied the effects exerted by cortical stimulation on the synchronization among thalamic units. Parallel experiments [Steriade et al. (1996) J. Neurosci. 16, 392-417] in this laboratory have demonstrated the similarity between the slow oscillation (<1 Hz) under ketamine-xylazine anaesthesia and that occurring during the natural state of resting sleep. Spontaneous activity was recorded simultaneously, with independent microelectrodes, from groups of two to five physiologically identified neurons. The rhythmicity of spontaneous activity and the temporal relations between cellular discharges were statistically evaluated by auto-and crosscorrelation techniques. We have found no topography in the distribution of synchronization between thalamic reticular and thalamocortical cells. Only the slow, cortical-generated oscillation (<1 Hz) displayed a stable frequency and correlation among groups of cortical and thalamic cells. The other two sleep oscillations (thalamic-generated spindles at 7-14 Hz and clock-like delta at 1-4 Hz) fluctuated in frequency and the degree of correlation between neurons varied. Cortical volleys entrained and synchronized thalamic cells, and triggered synchronized spindling in the thalamus.
Brain Research, 1984
In behaving cats trained to press a bar for small aliquots of milk reward, single neuronal firing patterns were monitored from the nucleus reticularis (NR) thalami during bar bressing (BP), subsequent quiet wakefulness with EEG spindles (S-QW), grooming behavior (GR) and slow-wave sleep (SWS). The temporal patterns in the neuronal spike trains were analyzed using a non-parametric method based on relative relations between sequential spike intervals. The deviations of pattern occurrences from the random model were quantified. During BP, specific patterns occurred much more often while others occurred much less often than predicted by the random model. Patterns that were dominant during BP, were selectively suppressed or virtually eliminated during S-QW, GR and SWS, despite the increased firing rate; and, vice versa, patterns that were suppressed below chance level during BP, became dominant during S-QW, GR and SWS. The magnitudes of these inversions of the statistical distribution of patterns were not random but graded and positively correlated, thus indicating that they were homeostatically controlled. Since the inversions were already evident shortly after the satiated animal ceased bar pressing, they may be related to the 'need' for sleep. On the basis of the known mechanisms of pattern generation and changes in receptors for putative transmitters, it was postulated that the inversions of pattern distribution are related to the recuperative function of SWS, i.e. resensitization of receptors that had been desensitized during the animal's stereotypic BP performance. The NR and other neuronal ensembles seem to constitute an oscillatory system with two modes of reciprocal connectivities: one is supporting wakefulness and emission of specific firing patterns, and the other is incompatible with wakefulness and instead is associated with inversion of statistical distribution of firing patterns and recuperative function of SWS.
Model of thalamocortical slow-wave sleep oscillations and transitions to activated states
2002
During natural slow-wave sleep (SWS) in nonanesthetized cats, silent (down) states alternate with active (up) states; the down states are absent during rapid-eye-movement sleep and waking. Oscillations (Ͻ1 Hz) in SWS and transformation to an activated awake state were investigated with intracellular recordings in vivo and with computational models of the corticothalamic system. Occasional summation of the miniature EPSPs during the hyperpolarized (silent) phase of SWS oscillation activated the persistent sodium current and depolarized the membrane of cortical pyramidal (PY) cells sufficiently for spike generation. In the model, this triggered the active phase, which was maintained by lateral PY-PY excitation and persistent sodium current. Progressive depression of the excitatory interconnections and activation of Ca 2ϩ -dependent K ϩ current led to termination of the 20-25 Hz activity after 500-1000 msec. Including thalamocortical (TC) and thalamic reticular neurons in the model increased the du-ration of the active epochs up to 1-1.5 sec and introduced waning spindle sequences. An increase in acetylcholine activity, which is associated with activated states, was modeled by the reduction in the K ϩ leak current in PY and TC cells and by a decrease in intracortical PY-PY synaptic conductances. These changes eliminated the hyperpolarizing phases of network activity and transformed cortical neurons to tonic firing at 15-20 Hz. During the transition from SWS to the activated state, the input resistance of cortical neurons gradually increased and, in a fully activated state, reached the same or even higher values as during silent phases of SWS oscillations. The model describes many essential features of SWS and activated states in the thalamocortical system as well as the transition between them.
Sensorimotor cortical influences on cuneate nucleus rhythmic activity in the anesthetized cat
Neuroscience, 1999
This work aimed to study whether the sensorimotor cerebral cortex spreads down its rhythmic patterns of activity to the dorsal column nuclei. Extracellular and intracellular recordings were obtained from the cuneate nucleus of chloralose-anesthetized cats. From a total of 140 neurons tested (106 cuneolemniscal), 72 showed spontaneous rhythmic activity within the slow (Ͻ1 Hz), d (1-4 Hz), spindle (5-15 Hz) and higher frequencies, with seven cells having the d rhythm coupled to slow oscillations. The spindle activity recorded in the cuneate was tightly coupled to the thalamo-cortico-thalamic spindle rhythmicity. Bilateral or contralateral removal of the frontoparietal cortex abolished the cuneate slow and spindle oscillations. Oscillatory paroxysmal activity generated by fast electrical stimulation (50-100 Hz/1-2 s) of the sensorimotor cortex induced burst firing synchronized with the paroxysmal cortical "spike" on all the non-lemniscal neurons, and inhibitory responses also coincident with the cortical paroxysmal "spike" in the majority (71%) of the cuneolemniscal cells. The remaining lemniscal-projecting neurons showed bursting activity (11%) or sequences of excitation-inhibition (18%) also time-locked to the cortical paroxysmal "spike". Additionally, the cerebral cortex induced coherent oscillatory activity between thalamic ventroposterolateral and cuneate neurons. Electrolytic lesion of the pyramidal tract abolished the cortically induced effects on the contralateral cuneate nucleus, as well as on the ipsilateral medial lemniscus. The results demonstrate that the sensorimotor cortex imposes its rhythmic patterns on the cuneate nucleus through the pyramidal tract, and that the corticocuneate network can generate normal and abnormal patterns of synchronized activity, such as d waves, spindles and spike-and-wave complexes. The cuneate neurons, however, are able to generate oscillatory activity above 1 Hz in the absence of cortical input, which implies that the cerebral cortex probably imposes its rhythmicity on the cuneate by matching the intrinsic preferred oscillatory frequency of cuneate neurons.
Slow wave sleep is accompanied by release of certain amino acids in the thalamus of cats
NeuroReport, 1997
It is an old idea that sleep has a biochemical equivalent due to the altered metabolism in the brain. Recently, it was disclosed that generation of slow waves in the EEG is causally related to the calcium spike genesis in the thalamus. This enhanced calcium influx could result in changes in cellular metabolism in neurones and astrocytes. We assumed, that as in other tissues, an altered metabolic state of brain cells is reflected by amino acid release to the extracellular space. Using an in vivo microdialysis technique, we measured increase of neurotransmitter and non-transmitter amino acids in the thalamus of freely moving cats. Our findings advance the investigation of sleep related biochemical changes in the brain.
Slow and fast rhythms generated in the cerebral cortex of the anesthetized mouse
Journal of Neurophysiology, 2011
A characterization of the oscillatory activity in the cerebral cortex of the mouse was realized under ketamine anesthesia. Bilateral recordings were obtained from deep layers of primary visual, somatosensory, motor, and medial prefrontal cortex. A slow oscillatory activity consisting of up and down states was detected, the average frequency being 0.97 Hz in all areas. Different parameters of the oscillation were estimated across cortical areas, including duration of up and down states and their variability, speed of state transitions, and population firing rate. Similar values were obtained for all areas except for prefrontal cortex, which showed significant faster down-to-up state transitions, higher firing rate during up states, and more regular cycles. The wave propagation patterns in the anteroposterior axis in motor cortex and the mediolateral axis in visual cortex were studied with multielectrode recordings, yielding speed values between 8 and 93 mm/s. The firing of single units was analyzed with respect to the population activity. The most common pattern was that of neurons firing in Ͼ90% of the up states with 1-6 spikes. Finally, fast rhythms (beta, low gamma, and high gamma) were analyzed, all of them showing significantly larger power during up states than in down states. Prefrontal cortex exhibited significantly larger power in both beta and gamma bands (up to 1 order of magnitude larger in the case of high gamma) than the rest of the cortical areas. This study allows us to carry out interareal comparisons and provides a baseline to compare against cortical emerging activity from genetically altered animals. oscillations; in vivo recording; ketamine; up states; sleep; spontaneous activity SLOW OSCILLATIONS (Ͻ1 Hz) occurring during slow-wave sleep and ketamine anesthesia were originally characterized in the neocortex of the cat (Steriade et al. 1993). During this rhythmic activity, the cortical network switches between depolarized, active periods or up states and silent periods or down states. During up states, the recurrency within the network maintains persistent activity with a functional structure that often reproduces that occurring during the cortical processing in the awake state (