6
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Cortical drive and thalamic feed-forward inhibition control thalamic output synchrony during absence seizures

      research-article
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Behaviorally and pathologically relevant cortico-thalamo-cortical oscillations are driven by diverse interacting cell-intrinsic and synaptic processes. However, the mechanism that gives rise to the paroxysmal oscillations of absence seizures (ASs) remains unknown. Here we report that during ASs in behaving animals, cortico-thalamic excitation drives thalamic firing by preferentially eliciting tonic rather than T-type Ca 2+ channels (T-channels)-dependent burst firing in thalamocortical (TC) neurons, and by temporally framing thalamic output via feed-forward reticular thalamic (NRT)-to-TC neuron inhibition. In TC neurons, overall ictal firing is markedly reduced and bursts rarely occur. Moreover, block of T-channels in cortical and NRT neurons suppresses ASs, but in TC neurons has no effect on seizures or on ictal thalamic output synchrony. These results demonstrate ictal bidirectional cortico-thalamic communications and provide the first mechanistic understanding of cortico-thalamo-cortical network firing dynamics during ASs in behaving animals.

          Related collections

          Most cited references65

          • Record: found
          • Abstract: found
          • Article: not found

          Accuracy of tetrode spike separation as determined by simultaneous intracellular and extracellular measurements.

          Simultaneous recording from large numbers of neurons is a prerequisite for understanding their cooperative behavior. Various recording techniques and spike separation methods are being used toward this goal. However, the error rates involved in spike separation have not yet been quantified. We studied the separation reliability of "tetrode" (4-wire electrode)-recorded spikes by monitoring simultaneously from the same cell intracellularly with a glass pipette and extracellularly with a tetrode. With manual spike sorting, we found a trade-off between Type I and Type II errors, with errors typically ranging from 0 to 30% depending on the amplitude and firing pattern of the cell, the similarity of the waveshapes of neighboring neurons, and the experience of the operator. Performance using only a single wire was markedly lower, indicating the advantages of multiple-site monitoring techniques over single-wire recordings. For tetrode recordings, error rates were increased by burst activity and during periods of cellular synchrony. The lowest possible separation error rates were estimated by a search for the best ellipsoidal cluster shape. Human operator performance was significantly below the estimated optimum. Investigation of error distributions indicated that suboptimal performance was caused by inability of the operators to mark cluster boundaries accurately in a high-dimensional feature space. We therefore hypothesized that automatic spike-sorting algorithms have the potential to significantly lower error rates. Implementation of a semi-automatic classification system confirms this suggestion, reducing errors close to the estimated optimum, in the range 0-8%.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Behavior-dependent short-term assembly dynamics in the medial prefrontal cortex.

            Although short-term plasticity is believed to play a fundamental role in cortical computation, empirical evidence bearing on its role during behavior is scarce. Here we looked for the signature of short-term plasticity in the fine-timescale spiking relationships of a simultaneously recorded population of physiologically identified pyramidal cells and interneurons, in the medial prefrontal cortex of the rat, in a working memory task. On broader timescales, sequentially organized and transiently active neurons reliably differentiated between different trajectories of the rat in the maze. On finer timescales, putative monosynaptic interactions reflected short-term plasticity in their dynamic and predictable modulation across various aspects of the task, beyond a statistical accounting for the effect of the neurons' co-varying firing rates. Seeking potential mechanisms for such effects, we found evidence for both firing pattern-dependent facilitation and depression, as well as for a supralinear effect of presynaptic coincidence on the firing of postsynaptic targets.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Thalamic amplification of cortical connectivity sustains attentional control

              While interactions between the thalamus and cortex are critical for cognitive function 1–3 , the exact contribution of the thalamus to these interactions is often unclear. Recent studies have shown diverse connectivity patterns across the thalamus 4,5 , but whether this diversity translates to thalamic functions beyond relaying information to or between cortical regions 6 is unknown. Here, by investigating prefrontal cortical (PFC) representation of two rules used to guide attention, we find that the mediodorsal thalamus (MD) sustains these representations without relaying categorical information. Specifically, MD input amplifies local PFC connectivity, enabling rule-specific neural sequences to emerge and thereby maintain rule representations. Consistent with this notion, broadly enhancing PFC excitability diminishes rule specificity and behavioral performance, while enhancing MD excitability improves both. Overall, our results define a previously unknown principle in neuroscience; thalamic control of functional cortical connectivity. This function indicates that the thalamus plays much more central roles in cognition than previously thought.
                Bookmark

                Author and article information

                Journal
                9809671
                21092
                Nat Neurosci
                Nat. Neurosci.
                Nature neuroscience
                1097-6256
                1546-1726
                29 November 2018
                16 April 2018
                May 2018
                04 December 2018
                : 21
                : 5
                : 744-756
                Affiliations
                [1 ]Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
                [2 ]Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
                [3 ]Team Waking, Lyon Neuroscience Research Center, CRNL, INSERM U1028, CNRS UMR5292, University of Lyon 1, Lyon, France
                [4 ]Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
                [5 ]Department of Physiology and Biochemistry, University of Malta, Msida, Malta
                [6 ]Sorbonne Université, CNRS, Inserm, Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), F-75005 Paris, France
                Author notes

                Authors’ contribution

                CMcC, F David, MLL, RCL, GD, NL and VC designed research and experiments; CMcC, F David, MV, MLL, GO, F Delicata, ZA, GR, GD and NL performed experiments and analysed data; CMcC, F David and VC wrote the manuscript with critical review by other authors.

                Article
                EMS80660
                10.1038/s41593-018-0130-4
                6278913
                29662216
                78744871-3b4b-4f69-96b1-01d48d54340a

                Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature.com/authors/editorial_policies/license.html#terms

                History
                Categories
                Article

                Neurosciences
                thalamic reticular nucleus,thalamic ventrobasal nucleus,neocortex,t-type ca2+ channels,feed-forward gaba-a inhibition,ensemble recordings,microdialysis

                Comments

                Comment on this article