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Grujic N, Polania R, Burdakov D. Neurobehavioral meaning of pupil size. Neuron 2024:S0896-6273(24)00406-9. [PMID: 38925124 DOI: 10.1016/j.neuron.2024.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 03/22/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024]
Abstract
Pupil size is a widely used metric of brain state. It is one of the few signals originating from the brain that can be readily monitored with low-cost devices in basic science, clinical, and home settings. It is, therefore, important to investigate and generate well-defined theories related to specific interpretations of this metric. What exactly does it tell us about the brain? Pupils constrict in response to light and dilate during darkness, but the brain also controls pupil size irrespective of luminosity. Pupil size fluctuations resulting from ongoing "brain states" are used as a metric of arousal, but what is pupil-linked arousal and how should it be interpreted in neural, cognitive, and computational terms? Here, we discuss some recent findings related to these issues. We identify open questions and propose how to answer them through a combination of well-defined tasks, neurocomputational models, and neurophysiological probing of the interconnected loops of causes and consequences of pupil size.
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Affiliation(s)
- Nikola Grujic
- Neurobehavioural Dynamics Lab, ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland.
| | - Rafael Polania
- Decision Neuroscience Lab, ETH Zürich, Department of Health Sciences and Technology, Winterthurstrasse 190, 8057 Zürich, Switzerland
| | - Denis Burdakov
- Neurobehavioural Dynamics Lab, ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland.
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2
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Su C, Mendes-Platt RF, Alonso JM, Swadlow HA, Bereshpolova Y. Visual Corticotectal Neurons in Awake Rabbits: Receptive Fields and Driving Monosynaptic Thalamocortical Inputs. J Neurosci 2024; 44:e1945232024. [PMID: 38485258 PMCID: PMC11079980 DOI: 10.1523/jneurosci.1945-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/26/2024] Open
Abstract
The superior colliculus receives powerful synaptic inputs from corticotectal neurons in the visual cortex. The function of these corticotectal neurons remains largely unknown due to a limited understanding of their response properties and connectivity. Here, we use antidromic methods to identify corticotectal neurons in awake male and female rabbits, and measure their axonal conduction times, thalamic inputs and receptive field properties. All corticotectal neurons responded to sinusoidal drifting gratings with a nonlinear (nonsinusoidal) increase in mean firing rate but showed pronounced differences in their ON-OFF receptive field structures that we classified into three groups, Cx, S2, and S1. Cx receptive fields had highly overlapping ON and OFF subfields as classical complex cells, S2 had largely separated ON and OFF subfields as classical simple cells, and S1 had a single ON or OFF subfield. Thus, all corticotectal neurons are homogeneous in their nonlinear spatial summation but very heterogeneous in their spatial integration of ON and OFF inputs. The Cx type had the fastest conducting axons, the highest spontaneous activity, and the strongest and fastest visual responses. The S2 type had the highest orientation selectivity, and the S1 type had the slowest conducting axons. Moreover, our cross-correlation analyses found that a subpopulation of corticotectal neurons with very fast conducting axons and high spontaneous firing rates (largely "Cx" type) receives monosynaptic input from retinotopically aligned thalamic neurons. This previously unrecognized fast-conducting thalamic-mediated corticotectal pathway may provide specialized information to superior colliculus and prime recipient neurons for subsequent corticotectal or retinal synaptic input.
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Affiliation(s)
- Chuyi Su
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
| | | | - Jose-Manuel Alonso
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
- Department of Biological Sciences, SUNY-Optometry, New York, New York
| | - Harvey A Swadlow
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
- Department of Biological Sciences, SUNY-Optometry, New York, New York
| | - Yulia Bereshpolova
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
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3
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Crombie D, Spacek MA, Leibold C, Busse L. Spiking activity in the visual thalamus is coupled to pupil dynamics across temporal scales. PLoS Biol 2024; 22:e3002614. [PMID: 38743775 PMCID: PMC11093384 DOI: 10.1371/journal.pbio.3002614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 04/05/2024] [Indexed: 05/16/2024] Open
Abstract
The processing of sensory information, even at early stages, is influenced by the internal state of the animal. Internal states, such as arousal, are often characterized by relating neural activity to a single "level" of arousal, defined by a behavioral indicator such as pupil size. In this study, we expand the understanding of arousal-related modulations in sensory systems by uncovering multiple timescales of pupil dynamics and their relationship to neural activity. Specifically, we observed a robust coupling between spiking activity in the mouse dorsolateral geniculate nucleus (dLGN) of the thalamus and pupil dynamics across timescales spanning a few seconds to several minutes. Throughout all these timescales, 2 distinct spiking modes-individual tonic spikes and tightly clustered bursts of spikes-preferred opposite phases of pupil dynamics. This multi-scale coupling reveals modulations distinct from those captured by pupil size per se, locomotion, and eye movements. Furthermore, coupling persisted even during viewing of a naturalistic movie, where it contributed to differences in the encoding of visual information. We conclude that dLGN spiking activity is under the simultaneous influence of multiple arousal-related processes associated with pupil dynamics occurring over a broad range of timescales.
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Affiliation(s)
- Davide Crombie
- Division of Neuroscience, Faculty of Biology, LMU Munich, Munich, Germany
- Graduate School of Systemic Neurosciences, LMU Munich, Munich, Germany
| | - Martin A. Spacek
- Division of Neuroscience, Faculty of Biology, LMU Munich, Munich, Germany
| | - Christian Leibold
- Division of Neuroscience, Faculty of Biology, LMU Munich, Munich, Germany
- Fakultät für Biologie & Bernstein Center Freiburg, Albert-Ludwigs-Universität Freiburg, Freiburg im Breisgau, Germany
| | - Laura Busse
- Division of Neuroscience, Faculty of Biology, LMU Munich, Munich, Germany
- Bernstein Center for Computational Neuroscience, Munich, Germany
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Jung YJ, Sun SH, Almasi A, Yunzab M, Meffin H, Ibbotson MR. Characterization of extracellular spike waveforms recorded in wallaby primary visual cortex. Front Neurosci 2023; 17:1244952. [PMID: 37746137 PMCID: PMC10517629 DOI: 10.3389/fnins.2023.1244952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023] Open
Abstract
Extracellular recordings were made from 642 units in the primary visual cortex (V1) of a highly visual marsupial, the Tammar wallaby. The receptive field (RF) characteristics of the cells were objectively estimated using the non-linear input model (NIM), and these were correlated with spike shapes. We found that wallaby cortical units had 68% regular spiking (RS), 12% fast spiking (FS), 4% triphasic spiking (TS), 5% compound spiking (CS) and 11% positive spiking (PS). RS waveforms are most often associated with recordings from pyramidal or spiny stellate cell bodies, suggesting that recordings from these cell types dominate in the wallaby cortex. In wallaby, 70-80% of FS and RS cells had orientation selective RFs and had evenly distributed linear and nonlinear RFs. We found that 47% of wallaby PS units were non-orientation selective and they were dominated by linear RFs. Previous studies suggest that the PS units represent recordings from the axon terminals of non-orientation selective cells originating in the lateral geniculate nucleus (LGN). If this is also true in wallaby, as strongly suggested by their low response latencies and bursty spiking properties, the results suggest that significantly more neurons in wallaby LGN are already orientation selective. In wallaby, less than 10% of recorded spikes had triphasic (TS) or sluggish compound spiking (CS) waveforms. These units had a mixture of orientation selective and non-oriented properties, and their cellular origins remain difficult to classify.
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Affiliation(s)
- Young Jun Jung
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
- National Vision Research Institute, Australian College of Optometry Carlton, Carlton, VIC, Australia
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Shi H. Sun
- National Vision Research Institute, Australian College of Optometry Carlton, Carlton, VIC, Australia
| | - Ali Almasi
- National Vision Research Institute, Australian College of Optometry Carlton, Carlton, VIC, Australia
| | - Molis Yunzab
- National Vision Research Institute, Australian College of Optometry Carlton, Carlton, VIC, Australia
| | - Hamish Meffin
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
| | - Michael R. Ibbotson
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
- National Vision Research Institute, Australian College of Optometry Carlton, Carlton, VIC, Australia
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, VIC, Australia
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5
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Sanchez AN, Alitto HJ, Rathbun DL, Fisher TG, Usrey WM. Stimulus contrast modulates burst activity in the lateral geniculate nucleus. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 4:100096. [PMID: 37397805 PMCID: PMC10313900 DOI: 10.1016/j.crneur.2023.100096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 06/03/2023] [Accepted: 06/08/2023] [Indexed: 07/04/2023] Open
Abstract
Burst activity is a ubiquitous feature of thalamic neurons and is well documented for visual neurons in the lateral geniculate nucleus (LGN). Although bursts are often associated with states of drowsiness, they are also known to convey visual information to cortex and are particularly effective in evoking cortical responses. The occurrence of thalamic bursts depends on (1) the inactivation gate of T-type Ca2+ channels (T-channels), which become de-inactivated following periods of increased membrane hyperpolarization, and (2) the opening of the T-channel activation gate, which has voltage-threshold and rate-of-change (δv/δt) requirements. Given the time/voltage relationship for the generation of Ca2+ potentials that underlie burst events, it is reasonable to predict that geniculate bursts are influenced by the luminance contrast of drifting grating stimuli, with the null phase of higher contrast stimuli evoking greater hyperpolarization followed by a larger dv/dt than the null phase of lower contrast stimuli. To determine the relationship between stimulus contrast and burst activity, we recorded the spiking activity of cat LGN neurons while presenting drifting sine-wave gratings that varied in luminance contrast. Results show that burst rate, reliability, and timing precision are significantly greater with higher contrast stimuli compared with lower contrast stimuli. Additional analysis from simultaneous recordings of synaptically connected retinal ganglion cells and LGN neurons further reveals the time/voltage dynamics underlying burst activity. Together, these results support the hypothesis that stimulus contrast and the biophysical properties underlying the state of T-type Ca2+ channels interact to influence burst activity, presumably to facilitate thalamocortical communication and stimulus detection.
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Affiliation(s)
| | - Henry J. Alitto
- Center for Neuroscience, University of California Davis, 95618, USA
| | - Daniel L. Rathbun
- Dept. of Ophthalmology, Detroit Inst. of Ophthalmology, Henry Ford Health System, Detroit, MI, 48202, USA
| | | | - W. Martin Usrey
- Center for Neuroscience, University of California Davis, 95618, USA
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Reinhold K, Resulaj A, Scanziani M. Brain State-Dependent Modulation of Thalamic Visual Processing by Cortico-Thalamic Feedback. J Neurosci 2023; 43:1540-1554. [PMID: 36653192 PMCID: PMC10008059 DOI: 10.1523/jneurosci.2124-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/21/2022] [Accepted: 11/28/2022] [Indexed: 01/20/2023] Open
Abstract
The behavioral state of a mammal impacts how the brain responds to visual stimuli as early as in the dorsolateral geniculate nucleus of the thalamus (dLGN), the primary relay of visual information to the cortex. A clear example of this is the markedly stronger response of dLGN neurons to higher temporal frequencies of the visual stimulus in alert as compared with quiescent animals. The dLGN receives strong feedback from the visual cortex, yet whether this feedback contributes to these state-dependent responses to visual stimuli is poorly understood. Here, we show that in male and female mice, silencing cortico-thalamic feedback profoundly reduces state-dependent differences in the response of dLGN neurons to visual stimuli. This holds true for dLGN responses to both temporal and spatial features of the visual stimulus. These results reveal that the state-dependent shift of the response to visual stimuli in an early stage of visual processing depends on cortico-thalamic feedback.SIGNIFICANCE STATEMENT Brain state affects even the earliest stages of sensory processing. A clear example of this phenomenon is the change in thalamic responses to visual stimuli depending on whether the animal's brain is in an alert or quiescent state. Despite the radical impact that brain state has on sensory processing, the underlying circuits are still poorly understood. Here, we show that both the temporal and spatial response properties of thalamic neurons to visual stimuli depend on the state of the animal and, crucially, that this state-dependent shift relies on the feedback projection from visual cortex to thalamus.
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Affiliation(s)
- Kimberly Reinhold
- Neurosciences Graduate Program, University of California San Diego, La Jolla, 92093, California
- Center for Neural Circuits and Behavior, Neurobiology Section and Department of Neuroscience, University of California San Diego, La Jolla, 92093, California
- Department of Physiology, University of California San Francisco, San Francisco, 94143, California
| | - Arbora Resulaj
- Center for Neural Circuits and Behavior, Neurobiology Section and Department of Neuroscience, University of California San Diego, La Jolla, 92093, California
- Department of Physiology, University of California San Francisco, San Francisco, 94143, California
- Howard Hughes Medical Institute, University of California San Francisco, San Francisco, 94143, California
| | - Massimo Scanziani
- Center for Neural Circuits and Behavior, Neurobiology Section and Department of Neuroscience, University of California San Diego, La Jolla, 92093, California
- Department of Physiology, University of California San Francisco, San Francisco, 94143, California
- Howard Hughes Medical Institute, University of California San Francisco, San Francisco, 94143, California
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7
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Franke K, Willeke KF, Ponder K, Galdamez M, Zhou N, Muhammad T, Patel S, Froudarakis E, Reimer J, Sinz FH, Tolias AS. State-dependent pupil dilation rapidly shifts visual feature selectivity. Nature 2022; 610:128-134. [PMID: 36171291 PMCID: PMC10635574 DOI: 10.1038/s41586-022-05270-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 08/23/2022] [Indexed: 11/09/2022]
Abstract
To increase computational flexibility, the processing of sensory inputs changes with behavioural context. In the visual system, active behavioural states characterized by motor activity and pupil dilation1,2 enhance sensory responses, but typically leave the preferred stimuli of neurons unchanged2-9. Here we find that behavioural state also modulates stimulus selectivity in the mouse visual cortex in the context of coloured natural scenes. Using population imaging in behaving mice, pharmacology and deep neural network modelling, we identified a rapid shift in colour selectivity towards ultraviolet stimuli during an active behavioural state. This was exclusively caused by state-dependent pupil dilation, which resulted in a dynamic switch from rod to cone photoreceptors, thereby extending their role beyond night and day vision. The change in tuning facilitated the decoding of ethological stimuli, such as aerial predators against the twilight sky10. For decades, studies in neuroscience and cognitive science have used pupil dilation as an indirect measure of brain state. Our data suggest that, in addition, state-dependent pupil dilation itself tunes visual representations to behavioural demands by differentially recruiting rods and cones on fast timescales.
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Affiliation(s)
- Katrin Franke
- Institute for Ophthalmic Research, Tübingen University, Tübingen, Germany.
- Center for Integrative Neuroscience, Tübingen University, Tübingen, Germany.
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA.
| | - Konstantin F Willeke
- Institute for Bioinformatics and Medical Informatics, Tübingen University, Tübingen, Germany
- Department of Computer Science, Göttingen University, Göttingen, Germany
| | - Kayla Ponder
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Mario Galdamez
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Na Zhou
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Taliah Muhammad
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Saumil Patel
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Emmanouil Froudarakis
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Greece
| | - Jacob Reimer
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Fabian H Sinz
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Institute for Bioinformatics and Medical Informatics, Tübingen University, Tübingen, Germany
- Department of Computer Science, Göttingen University, Göttingen, Germany
| | - Andreas S Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
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Histed MH, O’Rawe JF. From choices to internal states. Nat Neurosci 2022; 25:138-139. [DOI: 10.1038/s41593-021-01008-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Objective neuromodulation basis for intrafascicular artificial somatosensation through carbon nanotube yarn electrodes. J Neurosci Methods 2022; 369:109481. [PMID: 35032498 DOI: 10.1016/j.jneumeth.2022.109481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 12/13/2021] [Accepted: 01/10/2022] [Indexed: 11/20/2022]
Abstract
BACKGROUND Intrafascicular electrical stimulation has been extensively adopted to achieve sensory feedback for limb amputees. Axon-like carbon nanotube yarn (CNTy) electrodes with both promising flexibility and spatial selectivity index (SSI) can be fascinating alternatives to generate artificial somatosensation. NEW METHOD Here we systematically disclose objective neuromodulation basis for artificial somatosensation through intrafascicular CNTy electrodes. CNTy electrodes with different exposed lengths were utilized for electrically stimulating tibial nerves in twelve rats. Somatosensory evoked potentials (SEPs) were recorded synchronously using an epidural thirty-channel electrode array. Spatiotemporal characteristics of SEPs were analyzed as current pulse amplitude (PA), pulse width (PW) and pulse frequency (PF) varied. RESULTS The current thresholds at 1Hz exhibit the lowest means when compared with those at 4 and 8Hz for most CNTy electrodes (20/28). For all the electrodes, amplitudes of SEPs and activated areas of perceptive fields increase with PWs and PAs rising, and decrease remarkably with PFs from 1 to 8Hz. Latencies of P1 and N1 of SEP peaks gradually reduced with PWs and PAs advancing. Considering high SSIs, relatively stable current thresholds, wider variation ranges of sensory magnitudes and optimal stability of perceptive fields, the L-200 μm electrodes are preferable for neuromodulation with PFs of 1 - 8Hz, PWs of 100 - 800 μs and PAs of 2 - 64 μA. COMPARISON WITH EXISTING METHODS New-type CNTy electrodes possess both promising flexibility and SSI when compared with other neural interfaces. We systematically explore objective neuromodulation basis for artificial somatosensation through CNTy electrodes for the first time. CONCLUSIONS Significantly higher SSIs, lower current and charge thresholds exist for CNTy electrodes in comparison with other peripheral-nerve interfaces. This study can, for the first time, lay a solid neuromodulation foundation for CNTy electrodes to achieve fine sensory feedback.
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10
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Fernandez-Leon JA, Engelke DS, Aquino-Miranda G, Goodson A, Rasheed MN, Do Monte FH. Neural correlates and determinants of approach-avoidance conflict in the prelimbic prefrontal cortex. eLife 2021; 10:74950. [PMID: 34913438 PMCID: PMC8853658 DOI: 10.7554/elife.74950] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 12/13/2021] [Indexed: 12/04/2022] Open
Abstract
The recollection of environmental cues associated with threat or reward allows animals to select the most appropriate behavioral responses. Neurons in the prelimbic (PL) cortex respond to both threat- and reward-associated cues. However, it remains unknown whether PL regulates threat-avoidance vs. reward-approaching responses when an animals’ decision depends on previously associated memories. Using a conflict model in which male Long–Evans rats retrieve memories of shock- and food-paired cues, we observed two distinct phenotypes during conflict: (1) rats that continued to press a lever for food (Pressers) and (2) rats that exhibited a complete suppression in food seeking (Non-pressers). Single-unit recordings revealed that increased risk-taking behavior in Pressers is associated with persistent food-cue responses in PL, and reduced spontaneous activity in PL glutamatergic (PLGLUT) neurons during conflict. Activating PLGLUT neurons in Pressers attenuated food-seeking responses in a neutral context, whereas inhibiting PLGLUT neurons in Non-pressers reduced defensive responses and increased food approaching during conflict. Our results establish a causal role for PLGLUT neurons in mediating individual variability in memory-based risky decision-making by regulating threat-avoidance vs. reward-approach behaviors.
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Affiliation(s)
| | - Douglas S Engelke
- Department of Neurobiology and Anatomy, The University of Texas Health Science Center at Houston, Houston, United States
| | - Guillermo Aquino-Miranda
- Department of Neurobiology and Anatomy, The University of Texas Health Science Center at Houston, Houston, United States
| | | | - Maria N Rasheed
- Department of Neurobiology and Anatomy, The University of Texas Health Science Center at Houston, Houston, United States
| | - Fabricio H Do Monte
- Department of Neurobiology and Anatomy, The University of Texas Health Science Center at Houston, Houston, United States
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Molnár B, Sere P, Bordé S, Koós K, Zsigri N, Horváth P, Lőrincz ML. Cell Type-Specific Arousal-Dependent Modulation of Thalamic Activity in the Lateral Geniculate Nucleus. Cereb Cortex Commun 2021; 2:tgab020. [PMID: 34296165 PMCID: PMC8152899 DOI: 10.1093/texcom/tgab020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 12/04/2022] Open
Abstract
State-dependent thalamocortical activity is important for sensory coding, oscillations, and cognition. The lateral geniculate nucleus (LGN) relays visual information to the cortex, but the state-dependent spontaneous activity of LGN neurons in awake behaving animals remains controversial. Using a combination of pupillometry, extracellular, and intracellular recordings from identified LGN neurons in behaving mice, we show that thalamocortical (TC) neurons and interneurons are distinctly correlated to arousal forming two complementary coalitions. Intracellular recordings indicated that the membrane potential of LGN TC neurons was tightly correlated to fluctuations in pupil size. Inactivating the corticothalamic feedback to the LGN suppressed the arousal dependency of LGN neurons. Taken together, our results show that LGN neuronal membrane potential and action potential output are dynamically linked to arousal-dependent brain states in awake mice, and this might have important functional implications.
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Affiliation(s)
- Benedek Molnár
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences, University of Szeged, 6726 Szeged, Hungary
| | - Péter Sere
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences, University of Szeged, 6726 Szeged, Hungary
| | - Sándor Bordé
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences, University of Szeged, 6726 Szeged, Hungary
| | - Krisztián Koós
- Synthetic and Systems Biology Unit, Biological Research Centre, 6726 Szeged, Hungary
| | - Nikolett Zsigri
- Department of Physiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary
| | - Péter Horváth
- Synthetic and Systems Biology Unit, Biological Research Centre, 6726 Szeged, Hungary
| | - Magor L Lőrincz
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences, University of Szeged, 6726 Szeged, Hungary
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12
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Xiao J, Chen Z, Yu B. A Potential Mechanism of Sodium Channel Mediating the General Anesthesia Induced by Propofol. Front Cell Neurosci 2020; 14:593050. [PMID: 33343303 PMCID: PMC7746837 DOI: 10.3389/fncel.2020.593050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 11/10/2020] [Indexed: 12/19/2022] Open
Abstract
General anesthesia has revolutionized healthcare over the past 200 years and continues to show advancements. However, many phenomena induced by general anesthetics including paradoxical excitation are still poorly understood. Voltage-gated sodium channels (NaV) were believed to be one of the proteins targeted during general anesthesia. Based on electrophysiological measurements before and after propofol treatments of different concentrations, we mathematically modified the Hodgkin–Huxley sodium channel formulations and constructed a thalamocortical model to investigate the potential roles of NaV. The ion channels of individual neurons were modeled using the Hodgkin–Huxley type equations. The enhancement of propofol-induced GABAa current was simulated by increasing the maximal conductance and the time-constant of decay. Electroencephalogram (EEG) was evaluated as the post-synaptic potential from pyramidal (PY) cells. We found that a left shift in activation of NaV was induced primarily by a low concentration of propofol (0.3–10 μM), while a left shift in inactivation of NaV was induced by an increasing concentration (0.3–30 μM). Mathematical simulation indicated that a left shift of NaV activation produced a Hopf bifurcation, leading to cell oscillations. Left shift of NaV activation around a value of 5.5 mV in the thalamocortical models suppressed normal bursting of thalamocortical (TC) cells by triggering its chaotic oscillations. This led to irregular spiking of PY cells and an increased frequency in EEG readings. This observation suggests a mechanism leading to paradoxical excitation during general anesthesia. While a left shift in inactivation led to light hyperpolarization in individual cells, it inhibited the activity of the thalamocortical model after a certain depth of anesthesia. This finding implies that high doses of propofol inhibit the network partly by accelerating NaV toward inactivation. Additionally, this result explains why the application of sodium channel blockers decreases the requirement for general anesthetics. Our study provides an insight into the roles that NaV plays in the mechanism of general anesthesia. Since the activation and inactivation of NaV are structurally independent, it should be possible to avoid side effects by state-dependent binding to the NaV to achieve precision medicine in the future.
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Affiliation(s)
- Jinglei Xiao
- Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhengguo Chen
- College of Computer, National University of Defence Technology, Changsha, China
| | - Buwei Yu
- Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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13
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Bereshpolova Y, Hei X, Alonso JM, Swadlow HA. Three rules govern thalamocortical connectivity of fast-spike inhibitory interneurons in the visual cortex. eLife 2020; 9:60102. [PMID: 33289630 PMCID: PMC7723404 DOI: 10.7554/elife.60102] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/30/2020] [Indexed: 11/13/2022] Open
Abstract
Some cortical neurons receive highly selective thalamocortical (TC) input, but others do not. Here, we examine connectivity of single thalamic neurons (lateral geniculate nucleus, LGN) onto putative fast-spike inhibitory interneurons in layer 4 of rabbit visual cortex. We show that three 'rules' regulate this connectivity. These rules concern: (1) the precision of retinotopic alignment, (2) the amplitude of the postsynaptic local field potential elicited near the interneuron by spikes of the LGN neuron, and (3) the interneuron's response latency to strong, synchronous LGN input. We found that virtually all first-order fast-spike interneurons receive input from nearly all LGN axons that synapse nearby, regardless of their visual response properties. This was not the case for neighboring regular-spiking neurons. We conclude that profuse and highly promiscuous TC inputs to layer-4 fast-spike inhibitory interneurons generate response properties that are well-suited to mediate a fast, sensitive, and broadly tuned feed-forward inhibition of visual cortical excitatory neurons.
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Affiliation(s)
- Yulia Bereshpolova
- Department of Psychological Sciences, University of Connecticut, Storrs, United States
| | - Xiaojuan Hei
- Department of Psychological Sciences, University of Connecticut, Storrs, United States
| | - Jose-Manuel Alonso
- Department of Psychological Sciences, University of Connecticut, Storrs, United States.,Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, United States
| | - Harvey A Swadlow
- Department of Psychological Sciences, University of Connecticut, Storrs, United States.,Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, United States
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14
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Bostanciklioğlu M. Unexpected awakenings in severe dementia from case reports to laboratory. Alzheimers Dement 2020; 17:125-136. [PMID: 33064369 DOI: 10.1002/alz.12162] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 06/17/2020] [Accepted: 07/07/2020] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Case report notions of unexpected memory retrieval in patients with severe dementia near to death are starting to alter the central "irreversible" paradigm of dementia and locate dementia as a problem of memory retrieval, not consolidation. We suggest that the most likely central tenet of this paradoxical memory retrieval is the fluctuation of neuromodulators projecting from the brain stem to the medial prefrontal cortex and the hippocampus. The neuromodulation-centric explanation of this phenomenon aims to open the "irreversible" paradigm of dementia up for discussion and suggest a plausible treatment strategy by questioning how the devastating process of death fluctuates memory performance in severe dementia. BACKGROUND Supporting demented patients, who are mostly unresponsive, without making demands or asking a question and regarding them as valuable human beings unexpectedly improve their memory performance around the time of death. NEW LUCIDITY HYPOTHESIS Around the time of death, neurological signs (hyper-arousal and -attention) of demented people point out that neurotransmitter discharges are dramatically changed. Relatively resistant neuromodulator circuits to neurodegeneration can maintain optimal levels of arousal and attention for memory processing. In this way, unexpected episodes of lucidity can be triggered. Also, corticotropin-releasing peptides might increase mental clarity by increasing the excitability of the neuromodulator circuits. The science of memory retrieval is more complicated and nuanced than retrieval observations in case reports, but the rapid development of new techniques holds promise for future understanding of lucidity in severe dementia. MAJOR CHALLENGE FOR THE MODEL There is no an animal or human model to test this hypothesis; however, the similarities between neurological signs (instantaneous cognitive fluctuations) of delirium and paradoxical lucidity could provide a unique window to understand neural events of terminal lucidity on a modified animal model of delirium. Likewise, similarities between unexpected consciousness signs of terminal lucidity and lucid dreaming suggest that lucid dreaming episodes might be considered a human model for terminal lucidity research.
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15
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Campbell PW, Govindaiah G, Masterson SP, Bickford ME, Guido W. Synaptic properties of the feedback connections from the thalamic reticular nucleus to the dorsal lateral geniculate nucleus. J Neurophysiol 2020; 124:404-417. [PMID: 32609582 PMCID: PMC7500366 DOI: 10.1152/jn.00757.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The thalamic reticular nucleus (TRN) is a shell-like structure comprised of GABAergic neurons that surrounds the dorsal thalamus. While playing a key role in modulating thalamocortical interactions, TRN inhibition of thalamic activity is often thought of as having an all-or-none impact. Although TRN neurons have a dynamic firing range, it remains unclear how variable rates of TRN activity gate thalamocortical transmission. To address this, we examined the ultrastructural features and functional synaptic properties of the feedback connections in the mouse thalamus between TRN and the dorsal lateral geniculate nucleus (dLGN), the principal relay of retinal signals to visual cortex. Using electron microscopy to identify TRN input to dLGN, we found that TRN terminals formed synapses with non-GABAergic postsynaptic profiles. Compared with other nonretinal terminals in dLGN, those from TRN were relatively large and tended to contact proximal regions of relay cell dendrites. To evoke TRN activity in dLGN, we adopted an optogenetic approach by expressing ChR2, or a variant (ChIEF) in TRN terminals. Both in vitro and in vivo recordings revealed that repetitive stimulation of TRN terminals led to a frequency-dependent inhibition of dLGN activity, with higher rates of stimulation resulting in increasing levels of membrane hyperpolarization and corresponding decreases in spike firing. This relationship suggests that alterations in TRN activity lead to graded changes in relay cell spike firing.NEW & NOTEWORTHY The thalamic reticular nucleus (TRN) modulates thalamocortical transmission through inhibition. In mouse, TRN terminals in the dorsal lateral geniculate nucleus (dLGN) form synapses with relay neurons but not interneurons. Stimulation of TRN terminals in dLGN leads to a frequency-dependent form of inhibition, with higher rates of stimulation leading to a greater suppression of spike firing. Thus, TRN inhibition appears more dynamic than previously recognized, having a graded rather than an all-or-none impact on thalamocortical transmission.
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Affiliation(s)
- Peter W. Campbell
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Gubbi Govindaiah
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Sean P. Masterson
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Martha E. Bickford
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
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16
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Horwitz GD. Temporal information loss in the macaque early visual system. PLoS Biol 2020; 18:e3000570. [PMID: 31971946 PMCID: PMC6977937 DOI: 10.1371/journal.pbio.3000570] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 12/05/2019] [Indexed: 01/09/2023] Open
Abstract
Stimuli that modulate neuronal activity are not always detectable, indicating a loss of information between the modulated neurons and perception. To identify where in the macaque visual system information about periodic light modulations is lost, signal-to-noise ratios were compared across simulated cone photoreceptors, lateral geniculate nucleus (LGN) neurons, and perceptual judgements. Stimuli were drifting, threshold-contrast Gabor patterns on a photopic background. The sensitivity of LGN neurons, extrapolated to populations, was similar to the monkeys' at low temporal frequencies. At high temporal frequencies, LGN sensitivity exceeded the monkeys' and approached the upper bound set by cone photocurrents. These results confirm a loss of high-frequency information downstream of the LGN. However, this loss accounted for only about 5% of the total. Phototransduction accounted for essentially all of the rest. Together, these results show that low temporal frequency information is lost primarily between the cones and the LGN, whereas high-frequency information is lost primarily within the cones, with a small additional loss downstream of the LGN.
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Affiliation(s)
- Gregory D. Horwitz
- Department of Physiology and Biophysics, Washington National Primate Research Center, University of Washington, Seattle, Washington, United States of America
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17
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Soltani S, Chauvette S, Bukhtiyarova O, Lina JM, Dubé J, Seigneur J, Carrier J, Timofeev I. Sleep-Wake Cycle in Young and Older Mice. Front Syst Neurosci 2019; 13:51. [PMID: 31611779 PMCID: PMC6769075 DOI: 10.3389/fnsys.2019.00051] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/09/2019] [Indexed: 12/30/2022] Open
Abstract
Sleep plays a key role in multiple cognitive functions and sleep pattern changes with aging. Human studies revealed that aging decreases sleep efficiency and reduces the total sleep time, the time spent in slow-wave sleep (SWS), and the delta power (1–4 Hz) during sleep; however, some studies of sleep and aging in mice reported opposing results. The aim of our work is to estimate how features of sleep–wake state in mice during aging could correspond to age-dependent changes observed in human. In this study, we investigated the sleep/wake cycle in young (3 months old) and older (12 months old) C57BL/6 mice using local-field potentials (LFPs). We found that older adult mice sleep more than young ones but only during the dark phase of sleep-wake cycle. Sleep fragmentation and sleep during the active phase (dark phase of cycle), homologous to naps, were higher in older mice. Older mice show a higher delta power in frontal cortex, which was accompanied with similar trend for age differences in slow wave density. We also investigated regional specificity of sleep–wake electrographic activities and found that globally posterior regions of the cortex show more rapid eye movement (REM) sleep whereas somatosensory cortex displays more often SWS patterns. Our results indicate that the effects of aging on the sleep–wake activities in mice occur mainly during the dark phase and the electrode location strongly influence the state detection. Despite some differences in sleep–wake cycle during aging between human and mice, some features of mice sleep share similarity with human sleep during aging.
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Affiliation(s)
- Sara Soltani
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec, QC, Canada.,CERVO Brain Research Centre, Québec, QC, Canada
| | | | - Olga Bukhtiyarova
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec, QC, Canada.,CERVO Brain Research Centre, Québec, QC, Canada
| | - Jean-Marc Lina
- Center for Advanced Research in Sleep Medicine, Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Ile de Montréal, Montreal, QC, Canada.,École de Technologie Supérieure, Montreal, QC, Canada
| | - Jonathan Dubé
- Center for Advanced Research in Sleep Medicine, Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Ile de Montréal, Montreal, QC, Canada.,Department of Psychology, Université de Montréal, Montreal, QC, Canada
| | | | - Julie Carrier
- Center for Advanced Research in Sleep Medicine, Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Ile de Montréal, Montreal, QC, Canada.,Department of Psychology, Université de Montréal, Montreal, QC, Canada
| | - Igor Timofeev
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec, QC, Canada.,CERVO Brain Research Centre, Québec, QC, Canada
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18
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Modulation of Spontaneous and Light-Induced Activity in the Rat Dorsal Lateral Geniculate Nucleus by General Brain State Alterations under Urethane Anesthesia. Neuroscience 2019; 413:279-293. [DOI: 10.1016/j.neuroscience.2019.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/23/2019] [Accepted: 06/12/2019] [Indexed: 12/21/2022]
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19
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Bereshpolova Y, Stoelzel CR, Su C, Alonso JM, Swadlow HA. Activation of a Visual Cortical Column by a Directionally Selective Thalamocortical Neuron. Cell Rep 2019; 27:3733-3740.e3. [PMID: 31242407 DOI: 10.1016/j.celrep.2019.05.094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/07/2019] [Accepted: 05/22/2019] [Indexed: 01/26/2023] Open
Abstract
The retinas of rabbits and rodents have directionally selective (DS) retinal ganglion cells that convey directional signals through the lateral geniculate nucleus (LGN) of the thalamus to the primary visual cortex (V1). Notably, the function and synaptic impact in V1 of these directional LGN signals are unknown. Here we measured, in awake rabbits, the synaptic impact generated in V1 by individual LGN DS neurons. We show that these neurons make fast and strong connections in layers 4 and 6, with postsynaptic effects that are similar to those made by LGN concentric neurons, the main thalamic drivers of V1. By contrast, the synaptic impact of LGN DS neurons on superficial cortical layers was not detectable. These results suggest that LGN DS neurons activate a cortical column by targeting the main cortical input layers and that the role of DS input to superficial cortical layers is likely to be weak and/or modulatory.
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Affiliation(s)
- Yulia Bereshpolova
- Department of Psychological Sciences, University of Connecticut, Storrs, CT 06269, USA
| | - Carl R Stoelzel
- Department of Psychological Sciences, University of Connecticut, Storrs, CT 06269, USA
| | - Chuyi Su
- Department of Psychological Sciences, University of Connecticut, Storrs, CT 06269, USA
| | - Jose-Manuel Alonso
- Department of Psychological Sciences, University of Connecticut, Storrs, CT 06269, USA; Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY 10036, USA
| | - Harvey A Swadlow
- Department of Psychological Sciences, University of Connecticut, Storrs, CT 06269, USA; Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY 10036, USA.
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20
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The Augmentation of Retinogeniculate Communication during Thalamic Burst Mode. J Neurosci 2019; 39:5697-5710. [PMID: 31109958 DOI: 10.1523/jneurosci.2320-18.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 11/21/2022] Open
Abstract
Retinal signals are transmitted to cortex via neurons in the lateral geniculate nucleus (LGN), where they are processed in burst or tonic response mode. Burst mode occurs when LGN neurons are sufficiently hyperpolarized for T-type Ca2+ channels to deinactivate, allowing them to open in response to depolarization, which can trigger a high-frequency sequence of Na+-based spikes (i.e., burst). In contrast, T-type channels are inactivated during tonic mode and do not contribute to spiking. Although burst mode is commonly associated with sleep and the disruption of retinogeniculate communication, bursts can also be triggered by visual stimulation, thereby transforming the retinal signals relayed to the cortex. To determine how burst mode affects retinogeniculate communication, we made recordings from monosynaptically connected retinal ganglion cells and LGN neurons in male/female cats during visual stimulation. Our results reveal a robust augmentation of retinal signals within the LGN during burst mode. Specifically, retinal spikes were more effective and often triggered multiple LGN spikes during periods likely to have increased T-type Ca2+ channel activity. Consistent with the biophysical properties of T-type Ca2+ channels, analysis revealed that effect magnitude was correlated with the duration of the preceding thalamic interspike interval and occurred even in the absence of classically defined bursts. Importantly, the augmentation of geniculate responses to retinal input was not associated with a degradation of visual signals. Together, these results indicate a graded nature of response mode and suggest that, under certain conditions, bursts facilitate the transmission of visual information to the cortex by amplifying retinal signals.SIGNIFICANCE STATEMENT The thalamus is the gateway for retinal information traveling to the cortex. The lateral geniculate nucleus, like all thalamic nuclei, has two classically defined categories of spikes-tonic and burst-that differ in their underlying cellular mechanisms. Here we compare retinogeniculate communication during burst and tonic response modes. Our results show that retinogeniculate communication is enhanced during burst mode and visually evoked thalamic bursts, thereby augmenting retinal signals transmitted to cortex. Further, our results demonstrate that the influence of burst mode on retinogeniculate communication is graded and can be measured even in the absence of classically defined thalamic bursts.
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21
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Timofeev I, Chauvette S. Neuronal Activity During the Sleep-Wake Cycle. HANDBOOK OF SLEEP RESEARCH 2019. [DOI: 10.1016/b978-0-12-813743-7.00001-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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22
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Aydın Ç, Couto J, Giugliano M, Farrow K, Bonin V. Locomotion modulates specific functional cell types in the mouse visual thalamus. Nat Commun 2018; 9:4882. [PMID: 30451819 PMCID: PMC6242985 DOI: 10.1038/s41467-018-06780-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 09/26/2018] [Indexed: 12/13/2022] Open
Abstract
The visual system is composed of diverse cell types that encode distinct aspects of the visual scene and may form separate processing channels. Here we present further evidence for that hypothesis whereby functional cell groups in the dorsal lateral geniculate nucleus (dLGN) are differentially modulated during behavior. Using simultaneous multi-electrode recordings in dLGN and primary visual cortex (V1) of behaving mice, we characterized the impact of locomotor activity on response amplitude, variability, correlation and spatiotemporal tuning. Locomotion strongly impacts the amplitudes of dLGN and V1 responses but the effects on variability and correlations are relatively minor. With regards to tunings, locomotion enhances dLGN responses to high temporal frequencies, preferentially affecting ON transient cells and neurons with nonlinear responses to high spatial frequencies. Channel specific modulations may serve to highlight particular visual inputs during active behaviors. Locomotion is known to modulate neuronal firing in both the visual thalamus (LGN) and V1. Here, the authors characterize the LGN modulation in detail and report that neurons with transient ON responses for high spatial frequency stimuli show the strongest gain modulation.
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Affiliation(s)
- Çağatay Aydın
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001, Leuven, Belgium.,Department of Biology & Leuven Brain Institute, KU Leuven, 3000, Leuven, Belgium
| | - João Couto
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001, Leuven, Belgium.,Department of Biology & Leuven Brain Institute, KU Leuven, 3000, Leuven, Belgium
| | - Michele Giugliano
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001, Leuven, Belgium.,VIB, 3001, Leuven, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Brain Mind Institute, EPFL, Lausanne, Switzerland.,Department of Computer Science, University of Sheffield, Sheffield, UK
| | - Karl Farrow
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001, Leuven, Belgium.,Department of Biology & Leuven Brain Institute, KU Leuven, 3000, Leuven, Belgium.,VIB, 3001, Leuven, Belgium
| | - Vincent Bonin
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001, Leuven, Belgium. .,Department of Biology & Leuven Brain Institute, KU Leuven, 3000, Leuven, Belgium. .,VIB, 3001, Leuven, Belgium. .,imec, 3001, Leuven, Belgium.
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23
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Zimmerman EC, Grace AA. Prefrontal cortex modulates firing pattern in the nucleus reuniens of the midline thalamus via distinct corticothalamic pathways. Eur J Neurosci 2018; 48:3255-3272. [PMID: 30107061 PMCID: PMC6237082 DOI: 10.1111/ejn.14111] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 07/12/2018] [Accepted: 07/31/2018] [Indexed: 02/06/2023]
Abstract
The thalamus has long been recognized for its role in relaying sensory information from the periphery, a function accomplished by its "first-order" nuclei. However, a second category of thalamic nuclei, termed "higher-order" nuclei, have been shown instead to mediate communication between cortical areas. The nucleus reuniens of the midline thalamus (RE) is a higher-order nucleus known to act as a conduit of reciprocal communication between the medial prefrontal cortex (mPFC) and hippocampus. While anatomical and behavioural studies of RE are numerous, circuit-based electrophysiological studies, particularly those examining the impact of cortical input and the thalamic reticular nucleus (TRN) on RE neuron firing, are sparse. To characterize RE neuron firing properties and dissect the circuit dynamics of the infralimbic subdivision of the mPFC (ilPFC), the TRN and RE, we used in vivo, extracellular, single-unit recordings in male Sprague Dawley rats and manipulated neural activity using targeted pharmacological manipulations, electrical stimulation and a projection-specific implementation of designer receptors exclusively activated by designer drugs (DREADDs). We show that ilPFC inhibition reduces multiple burst firing parameters in RE, whereas ilPFC stimulation drives burst firing and dampens tonic firing. In addition, TRN inhibition reduces the number of spontaneously active neurons in RE. Finally, inhibition of ilPFC terminals in RE selectively enhances a subset of burst firing parameters. These findings demonstrate that ilPFC input, both via direct projections and via the TRN, can modulate RE neuron firing pattern in nuanced and complex ways. They also highlight the ilPFC-TRN-RE circuit as a likely critical component of prefrontal-hippocampal interactions.
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Affiliation(s)
- Eric C Zimmerman
- Departments of Neuroscience, Psychiatry, and Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Anthony A Grace
- Departments of Neuroscience, Psychiatry, and Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania
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24
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Abstract
Visual information reaches the cerebral cortex through a major thalamocortical pathway that connects the lateral geniculate nucleus (LGN) of the thalamus with the primary visual area of the cortex (area V1). In humans, ∼3.4 million afferents from the LGN are distributed within a V1 surface of ∼2400 mm2, an afferent number that is reduced by half in the macaque and by more than two orders of magnitude in the mouse. Thalamocortical afferents are sorted in visual cortex based on the spatial position of their receptive fields to form a map of visual space. The visual resolution within this map is strongly correlated with total number of thalamic afferents that V1 receives and the area available to sort them. The ∼20,000 afferents of the mouse are only sorted by spatial position because they have to cover a large visual field (∼300 deg) within just 4 mm2 of V1 area. By contrast, the ∼500,000 afferents of the cat are also sorted by eye input and light/dark polarity because they cover a smaller visual field (∼200 deg) within a much larger V1 area (∼400 mm2), a sorting principle that is likely to apply also to macaques and humans. The increased precision of thalamic sorting allows building multiple copies of the V1 visual map for left/right eyes and light/dark polarities, which become interlaced to keep neurons representing the same visual point close together. In turn, this interlaced arrangement makes cortical neurons with different preferences for stimulus orientation to rotate around single cortical points forming a pinwheel pattern that allows more efficient processing of objects and visual textures.
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25
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Busse L. The influence of locomotion on sensory processing and its underlying neuronal circuits. ACTA ACUST UNITED AC 2018. [DOI: 10.1515/nf-2017-a046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractProcessing of sensory information can be modulated in both cortex and thalamus by behavioral context, such as locomotion. During active behaviors, coding of sensory stimuli and perception are improved, in particular during physical activity of moderate intensity. These locomotion-related modulations seem to arise from a combination of mechanisms, including neuromodulation, the recruitment of inhibitory interneurons, and specific top-down or motor-related inputs. The application of new experimental methods in mice during walking under head-fixation on treadmills made it possible to study the circuit and cellular basis underlying modulations by behavioral context with unprecedented detail. This article reviews the current state of these studies and highlights some important open questions.
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Affiliation(s)
- Laura Busse
- Division of Neurobiology, Department Biology II, LMU Munich, Germany; Bernstein Center for Computational Neuroscience Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany, Phone: 49 (0) 89 218074305
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26
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Franci A, Drion G, Sepulchre R. Robust and tunable bursting requires slow positive feedback. J Neurophysiol 2017; 119:1222-1234. [PMID: 29357476 DOI: 10.1152/jn.00804.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We highlight that the robustness and tunability of a bursting model critically rely on currents that provide slow positive feedback to the membrane potential. Such currents have the ability to make the total conductance of the circuit negative in a timescale that is termed "slow" because it is intermediate between the fast timescale of the spike upstroke and the ultraslow timescale of even slower adaptation currents. We discuss how such currents can be assessed either in voltage-clamp experiments or in computational models. We show that, while frequent in the literature, mathematical and computational models of bursting that lack the slow negative conductance are fragile and rigid. Our results suggest that modeling the slow negative conductance of cellular models is important when studying the neuromodulation of rhythmic circuits at any broader scale. NEW & NOTEWORTHY Nervous system functions rely on the modulation of neuronal activity between different rhythmic patterns. The mechanisms of this modulation are still poorly understood. Using computational modeling, we show the critical role of currents that provide slow negative conductance, distinct from the fast negative conductance necessary for spike generation. The significance of the slow negative conductance for neuromodulation is often overlooked, leading to computational models that are rigid and fragile.
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Affiliation(s)
- Alessio Franci
- Department of Mathematics, Universidad Nacional Autónoma de México , Mexico City, Mexico
| | | | - Rodolphe Sepulchre
- Department of Engineering, University of Cambridge , Cambridge , United Kingdom
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27
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Beaman CB, Eagleman SL, Dragoi V. Sensory coding accuracy and perceptual performance are improved during the desynchronized cortical state. Nat Commun 2017; 8:1308. [PMID: 29101393 PMCID: PMC5670198 DOI: 10.1038/s41467-017-01030-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/13/2017] [Indexed: 01/26/2023] Open
Abstract
Cortical activity changes continuously during the course of the day. At a global scale, population activity varies between the ‘synchronized’ state during sleep and ‘desynchronized’ state during waking. However, whether local fluctuations in population synchrony during wakefulness modulate the accuracy of sensory encoding and behavioral performance is poorly understood. Here, we show that populations of cells in monkey visual cortex exhibit rapid fluctuations in synchrony ranging from desynchronized responses, indicative of high alertness, to highly synchronized responses. These fluctuations are local and control the trial variability in population coding accuracy and behavioral performance in a discrimination task. When local population activity is desynchronized, the correlated variability between neurons is reduced, and network and behavioral performance are enhanced. These findings demonstrate that the structure of variability in local cortical populations is not noise but rather controls how sensory information is optimally integrated with ongoing processes to guide network coding and behavior. Changes in synchrony of cortical populations are observed across the sleep-wake cycle, however the effect of fluctuations in synchrony during wakefulness is not understood. Here the authors show that visual cortical neurons have improved sensory encoding accuracy as well as improved perceptual performance during periods of local population desynchrony.
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Affiliation(s)
- Charles B Beaman
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas at Houston, Houston, TX, 77030, USA
| | - Sarah L Eagleman
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas at Houston, Houston, TX, 77030, USA.,Department of Electrical and Computer Engineering, Rice University, George R. Brown School of Engineering, Houston, TX, 77005, USA
| | - Valentin Dragoi
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas at Houston, Houston, TX, 77030, USA.
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28
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Coulon P, Landisman CE. The Potential Role of Gap Junctional Plasticity in the Regulation of State. Neuron 2017; 93:1275-1295. [PMID: 28334604 DOI: 10.1016/j.neuron.2017.02.041] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 01/20/2017] [Accepted: 02/22/2017] [Indexed: 11/19/2022]
Abstract
Electrical synapses are the functional correlate of gap junctions and allow transmission of small molecules and electrical current between coupled neurons. Instead of static pores, electrical synapses are actually plastic, similar to chemical synapses. In the thalamocortical system, gap junctions couple inhibitory neurons that are similar in their biochemical profile, morphology, and electrophysiological properties. We postulate that electrical synaptic plasticity among inhibitory neurons directly interacts with the switching between different firing patterns in a state-dependent and type-dependent manner. In neuronal networks, electrical synapses may function as a modifiable resonance feedback system that enables stable oscillations. Furthermore, the plasticity of electrical synapses may play an important role in regulation of state, synchrony, and rhythmogenesis in the mammalian thalamocortical system, similar to chemical synaptic plasticity. Based on their plasticity, rich diversity, and specificity, electrical synapses are thus likely to participate in the control of consciousness and attention.
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Affiliation(s)
- Philippe Coulon
- Seattle Children's Research Institute, Center for Integrative Brain Research, Seattle, WA 98101, USA.
| | - Carole E Landisman
- Seattle Children's Research Institute, Center for Integrative Brain Research, Seattle, WA 98101, USA.
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A Comparison of Visual Response Properties in the Lateral Geniculate Nucleus and Primary Visual Cortex of Awake and Anesthetized Mice. J Neurosci 2017; 36:12144-12156. [PMID: 27903724 DOI: 10.1523/jneurosci.1741-16.2016] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/23/2016] [Accepted: 09/12/2016] [Indexed: 11/21/2022] Open
Abstract
The cerebral cortex of the mouse has become one of the most important systems for studying information processing and the neural correlates of behavior. Multiple studies have examined the first stages of visual cortical processing: primary visual cortex (V1) and its thalamic inputs from the dorsal lateral geniculate nucleus (dLGN), but more rarely in the lateral posterior nucleus (LP) in mice. Multiple single-unit surveys of dLGN and V1, both with electrophysiology and two-photon calcium imaging, have described receptive fields in anesthetized animals. Increasingly, awake animals are being used in physiological studies, so it is important to compare neuronal responses between awake and anesthetized state. We have performed a comprehensive survey of spatial and temporal response properties in V1, dLGN, and lateral posterior nucleus of both anesthetized and awake animals, using a common set of stimuli: drifting sine-wave gratings spanning a broad range of spatial and temporal parameters, and sparse noise stimuli consisting of flashed light and dark squares. Most qualitative receptive field parameters were found to be unchanged between the two states, such as most aspects of spatial processing, but there were significant differences in several parameters, most notably in temporal processing. Compared with anesthetized animals, the temporal frequency that evoked the peak response was shifted toward higher values in the dLGN of awake mice and responses were more sustained. Further, the peak response to a flashed stimulus was earlier in all three areas. Overall, however, receptive field properties in the anesthetized animal remain a good model for those in the awake animal. SIGNIFICANCE STATEMENT The primary visual cortex (V1) of the mouse and its inputs from visual thalamus (dLGN), have become a dominant model for studying information processing in the brain. Early surveys of visual response properties (receptive fields) were performed in anesthetized animals. Although most recent studies of V1 have been performed in awake animals to examine links between vision and behavior, there have been few comprehensive studies of receptive field properties in the awake mouse, especially in dLGN and lateral posterior nucleus. We have performed a comparative survey of receptive fields in dLGN, lateral posterior nucleus, and V1 in anesthetized and awake mice. We found multiple differences in processing of time-varying stimuli, whereas the spatial aspects of receptive fields remain comparatively unchanged.
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Differential Excitation of Distally versus Proximally Targeting Cortical Interneurons by Unitary Thalamocortical Bursts. J Neurosci 2017; 36:6906-16. [PMID: 27358449 DOI: 10.1523/jneurosci.0739-16.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 05/16/2016] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Thalamocortical neurons relay sensory and motor information to the neocortex using both single spikes and bursts; bursts prevail during low-vigilance states but also occur during awake behavior. Bursts are suggested to provide an alerting signal to the cortex and enhance stimulus detection, but the synaptic mechanisms underlying these effects are not clear, because the postsynaptic responses of different subtypes of cortical neurons to unitary thalamocortical bursts are mostly unknown. Using optogenetically guided recordings in mouse thalamocortical slices, we achieved the first reported paired intracellular recordings from nine monosynaptically connected thalamic and cortical neurons, including principal cells and two subtypes of inhibitory interneurons, and compared between cortical responses to single thalamocortical spikes and bursts. In 18 additional cortical neurons, we elicited unitary burst responses optogenetically. Short-term dynamics and temporal summation of burst-evoked EPSPs were cell-type dependent: in principal cells and somatostatin-containing (SOM), but not fast-spiking (FS), interneurons, peak response during a burst was on average more than twofold larger than the response to the first spike. Thus, firing a burst instead of a single spike would more than double the probability of firing in postsynaptic excitatory neurons and in SOM, but not FS, interneurons. Consistent with this prediction, FS interneurons held near firing threshold fired most often on the first burst component, whereas SOM interneurons fired only on the second or later components. By increasing excitation of principal cells together with SOM-mediated, distally directed inhibition, thalamocortical bursts could momentarily enhance the saliency of the ascending sensory stimulus over less urgent, top-down inputs. SIGNIFICANCE STATEMENT Thalamocortical neurons relay sensory and motor information to the cerebral cortex using both single spikes and high-frequency bursts, but the function of bursts is not fully understood. Using brain slices from mouse somatosensory thalamus and cortex, we achieved the first dual recordings of directly connected thalamic and cortical neurons and compared between cortical responses to single thalamic spikes and to bursts. We report that bursts enhanced the responses of excitatory neurons and of inhibitory interneurons that preferentially target dendrites. A potential consequence is that bursts will enhance the response to the immediate sensory event over responses to less urgent, modulatory inputs.
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Axonal Conduction Delays, Brain State, and Corticogeniculate Communication. J Neurosci 2017; 37:6342-6358. [PMID: 28559382 DOI: 10.1523/jneurosci.0444-17.2017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/18/2017] [Accepted: 05/24/2017] [Indexed: 11/21/2022] Open
Abstract
Thalamocortical conduction times are short, but layer 6 corticothalamic axons display an enormous range of conduction times, some exceeding 40-50 ms. Here, we investigate (1) how axonal conduction times of corticogeniculate (CG) neurons are related to the visual information conveyed to the thalamus, and (2) how alert versus nonalert awake brain states affect visual processing across the spectrum of CG conduction times. In awake female Dutch-Belted rabbits, we found 58% of CG neurons to be visually responsive, and 42% to be unresponsive. All responsive CG neurons had simple, orientation-selective receptive fields, and generated sustained responses to stationary stimuli. CG axonal conduction times were strongly related to modulated firing rates (F1 values) generated by drifting grating stimuli, and their associated interspike interval distributions, suggesting a continuum of visual responsiveness spanning the spectrum of axonal conduction times. CG conduction times were also significantly related to visual response latency, contrast sensitivity (C-50 values), directional selectivity, and optimal stimulus velocity. Increasing alertness did not cause visually unresponsive CG neurons to become responsive and did not change the response linearity (F1/F0 ratios) of visually responsive CG neurons. However, for visually responsive CG neurons, increased alertness nearly doubled the modulated response amplitude to optimal visual stimulation (F1 values), significantly shortened response latency, and dramatically increased response reliability. These effects of alertness were uniform across the broad spectrum of CG axonal conduction times.SIGNIFICANCE STATEMENT Corticothalamic neurons of layer 6 send a dense feedback projection to thalamic nuclei that provide input to sensory neocortex. While sensory information reaches the cortex after brief thalamocortical axonal delays, corticothalamic axons can exhibit conduction delays of <2 ms to 40-50 ms. Here, in the corticogeniculate visual system of awake rabbits, we investigate the functional significance of this axonal diversity, and the effects of shifting alert/nonalert brain states on corticogeniculate processing. We show that axonal conduction times are strongly related to multiple visual response properties, suggesting a continuum of visual responsiveness spanning the spectrum of corticogeniculate axonal conduction times. We also show that transitions between awake brain states powerfully affect corticogeniculate processing, in some ways more strongly than in layer 4.
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Long-range projections coordinate distributed brain-wide neural activity with a specific spatiotemporal profile. Proc Natl Acad Sci U S A 2016; 113:E8306-E8315. [PMID: 27930323 DOI: 10.1073/pnas.1616361113] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One challenge in contemporary neuroscience is to achieve an integrated understanding of the large-scale brain-wide interactions, particularly the spatiotemporal patterns of neural activity that give rise to functions and behavior. At present, little is known about the spatiotemporal properties of long-range neuronal networks. We examined brain-wide neural activity patterns elicited by stimulating ventral posteromedial (VPM) thalamo-cortical excitatory neurons through combined optogenetic stimulation and functional MRI (fMRI). We detected robust optogenetically evoked fMRI activation bilaterally in primary visual, somatosensory, and auditory cortices at low (1 Hz) but not high frequencies (5-40 Hz). Subsequent electrophysiological recordings indicated interactions over long temporal windows across thalamo-cortical, cortico-cortical, and interhemispheric callosal projections at low frequencies. We further observed enhanced visually evoked fMRI activation during and after VPM stimulation in the superior colliculus, indicating that visual processing was subcortically modulated by low-frequency activity originating from VPM. Stimulating posteromedial complex thalamo-cortical excitatory neurons also evoked brain-wide blood-oxygenation-level-dependent activation, although with a distinct spatiotemporal profile. Our results directly demonstrate that low-frequency activity governs large-scale, brain-wide connectivity and interactions through long-range excitatory projections to coordinate the functional integration of remote brain regions. This low-frequency phenomenon contributes to the neural basis of long-range functional connectivity as measured by resting-state fMRI.
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Paul K, Cauller LJ, Llano DA. Presence of a Chaotic Region at the Sleep-Wake Transition in a Simplified Thalamocortical Circuit Model. Front Comput Neurosci 2016; 10:91. [PMID: 27660609 PMCID: PMC5015482 DOI: 10.3389/fncom.2016.00091] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/18/2016] [Indexed: 01/20/2023] Open
Abstract
Sleep and wakefulness are characterized by distinct states of thalamocortical network oscillations. The complex interplay of ionic conductances within the thalamo-reticular-cortical network give rise to these multiple modes of activity and a rapid transition exists between these modes. To better understand this transition, we constructed a simplified computational model based on physiological recordings and physiologically realistic parameters of a three-neuron network containing a thalamocortical cell, a thalamic reticular neuron, and a corticothalamic cell. The network can assume multiple states of oscillatory activity, resembling sleep, wakefulness, and the transition between these two. We found that during the transition period, but not during other states, thalamic and cortical neurons displayed chaotic dynamics, based on the presence of strange attractors, estimation of positive Lyapunov exponents and the presence of a fractal dimension in the spike trains. These dynamics were quantitatively dependent on certain features of the network, such as the presence of corticothalamic feedback and the strength of inhibition between the thalamic reticular nucleus and thalamocortical neurons. These data suggest that chaotic dynamics facilitate a rapid transition between sleep and wakefulness and produce a series of experimentally testable predictions to further investigate the events occurring during the sleep-wake transition period.
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Affiliation(s)
- Kush Paul
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-ChampaignUrbana, IL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-ChampaignUrbana, IL, USA; School of Behavioral and Brain Sciences, University of Texas at DallasRichardson, TX, USA
| | - Lawrence J Cauller
- School of Behavioral and Brain Sciences, University of Texas at Dallas Richardson, TX, USA
| | - Daniel A Llano
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-ChampaignUrbana, IL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-ChampaignUrbana, IL, USA
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Sriram B, Meier PM, Reinagel P. Temporal and spatial tuning of dorsal lateral geniculate nucleus neurons in unanesthetized rats. J Neurophysiol 2016; 115:2658-71. [PMID: 26936980 DOI: 10.1152/jn.00812.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/29/2016] [Indexed: 12/29/2022] Open
Abstract
Visual response properties of neurons in the dorsolateral geniculate nucleus (dLGN) have been well described in several species, but not in rats. Analysis of responses from the unanesthetized rat dLGN will be needed to develop quantitative models that account for visual behavior of rats. We recorded visual responses from 130 single units in the dLGN of 7 unanesthetized rats. We report the response amplitudes, temporal frequency, and spatial frequency sensitivities in this population of cells. In response to 2-Hz visual stimulation, dLGN cells fired 15.9 ± 11.4 spikes/s (mean ± SD) modulated by 10.7 ± 8.4 spikes/s about the mean. The optimal temporal frequency for full-field stimulation ranged from 5.8 to 19.6 Hz across cells. The temporal high-frequency cutoff ranged from 11.7 to 33.6 Hz. Some cells responded best to low temporal frequency stimulation (low pass), and others were strictly bandpass; most cells fell between these extremes. At 2- to 4-Hz temporal modulation, the spatial frequency of drifting grating that drove cells best ranged from 0.008 to 0.18 cycles per degree (cpd) across cells. The high-frequency cutoff ranged from 0.01 to 1.07 cpd across cells. The majority of cells were driven best by the lowest spatial frequency tested, but many were partially or strictly bandpass. We conclude that single units in the rat dLGN can respond vigorously to temporal modulation up to at least 30 Hz and spatial detail up to 1 cpd. Tuning properties were heterogeneous, but each fell along a continuum; we found no obvious clustering into discrete cell types along these dimensions.
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Affiliation(s)
- Balaji Sriram
- Division of Biology, University of California, San Diego, California; and
| | - Philip M Meier
- Department of Neuroscience, University of California, San Diego, California
| | - Pamela Reinagel
- Division of Biology, University of California, San Diego, California; and
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35
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Whitmire CJ, Waiblinger C, Schwarz C, Stanley GB. Information Coding through Adaptive Gating of Synchronized Thalamic Bursting. Cell Rep 2016; 14:795-807. [PMID: 26776512 DOI: 10.1016/j.celrep.2015.12.068] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/07/2015] [Accepted: 12/11/2015] [Indexed: 11/27/2022] Open
Abstract
It has been posited that the regulation of burst/tonic firing in the thalamus could function as a mechanism for controlling not only how much but what kind of information is conveyed to downstream cortical targets. Yet how this gating mechanism is adaptively modulated on fast timescales by ongoing sensory inputs in rich sensory environments remains unknown. Using single-unit recordings in the rat vibrissa thalamus (VPm), we found that the degree of bottom-up adaptation modulated thalamic burst/tonic firing as well as the synchronization of bursting across the thalamic population along a continuum for which the extremes facilitate detection or discrimination of sensory inputs. Optogenetic control of baseline membrane potential in thalamus further suggests that this regulation may result from an interplay between adaptive changes in thalamic membrane potential and synaptic drive from inputs to thalamus, setting the stage for an intricate control strategy upon which cortical computation is built.
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Affiliation(s)
- Clarissa J Whitmire
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Christian Waiblinger
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA; Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen 72074, Germany; Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen 72074, Germany
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen 72074, Germany; Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen 72074, Germany
| | - Garrett B Stanley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.
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36
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37
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Urbain N, Salin PA, Libourel PA, Comte JC, Gentet LJ, Petersen CCH. Whisking-Related Changes in Neuronal Firing and Membrane Potential Dynamics in the Somatosensory Thalamus of Awake Mice. Cell Rep 2015; 13:647-656. [PMID: 26489463 DOI: 10.1016/j.celrep.2015.09.029] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 06/26/2015] [Accepted: 09/09/2015] [Indexed: 11/29/2022] Open
Abstract
The thalamus transmits sensory information to the neocortex and receives neocortical, subcortical, and neuromodulatory inputs. Despite its obvious importance, surprisingly little is known about thalamic function in awake animals. Here, using intracellular and extracellular recordings in awake head-restrained mice, we investigate membrane potential dynamics and action potential firing in the two major thalamic nuclei related to whisker sensation, the ventral posterior medial nucleus (VPM) and the posterior medial group (Pom), which receive distinct inputs from brainstem and neocortex. We find heterogeneous state-dependent dynamics in both nuclei, with an overall increase in action potential firing during active states. Whisking increased putative lemniscal and corticothalamic excitatory inputs onto VPM and Pom neurons, respectively. A subpopulation of VPM cells fired spikes phase-locked to the whisking cycle during free whisking, and these cells may therefore signal whisker position. Our results suggest differential processing of whisking comparing thalamic nuclei at both sub- and supra-threshold levels.
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Affiliation(s)
- Nadia Urbain
- Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland; Physiopathologie des Réseaux Neuronaux du Cycle Sommeil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France.
| | - Paul A Salin
- Physiopathologie des Réseaux Neuronaux du Cycle Sommeil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France
| | - Paul-Antoine Libourel
- Physiopathologie des Réseaux Neuronaux du Cycle Sommeil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France
| | - Jean-Christophe Comte
- Integrated Physiology of Brain Arousal Systems, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France
| | - Luc J Gentet
- Integrated Physiology of Brain Arousal Systems, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France
| | - Carl C H Petersen
- Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
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38
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Stoelzel CR, Huff JM, Bereshpolova Y, Zhuang J, Hei X, Alonso JM, Swadlow HA. Hour-long adaptation in the awake early visual system. J Neurophysiol 2015; 114:1172-82. [PMID: 26108950 DOI: 10.1152/jn.00116.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/16/2015] [Indexed: 12/30/2022] Open
Abstract
Sensory adaptation serves to adjust awake brains to changing environments on different time scales. However, adaptation has been studied traditionally under anesthesia and for short time periods. Here, we demonstrate in awake rabbits a novel type of sensory adaptation that persists for >1 h and acts on visual thalamocortical neurons and their synapses in the input layers of the visual cortex. Following prolonged visual stimulation (10-30 min), cells in the dorsal lateral geniculate nucleus (LGN) show a severe and prolonged reduction in spontaneous firing rate. This effect is bidirectional, and prolonged visually induced response suppression is followed by a prolonged increase in spontaneous activity. The reduction in thalamic spontaneous activity following prolonged visual activation is accompanied by increases in 1) response reliability, 2) signal detectability, and 3) the ratio of visual signal/spontaneous activity. In addition, following such prolonged activation of an LGN neuron, the monosynaptic currents generated by thalamic impulses in layer 4 of the primary visual cortex are enhanced. These results demonstrate that in awake brains, prolonged sensory stimulation can have a profound, long-lasting effect on the information conveyed by thalamocortical inputs to the visual cortex.
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Affiliation(s)
- Carl R Stoelzel
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Joseph M Huff
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Yulia Bereshpolova
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Jun Zhuang
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Xiaojuan Hei
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Jose-Manuel Alonso
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and Department of Biological Sciences, State University of New York, New York, New York
| | - Harvey A Swadlow
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and Department of Biological Sciences, State University of New York, New York, New York
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Cerina M, Szkudlarek HJ, Coulon P, Meuth P, Kanyshkova T, Nguyen XV, Göbel K, Seidenbecher T, Meuth SG, Pape HC, Budde T. Thalamic Kv 7 channels: pharmacological properties and activity control during noxious signal processing. Br J Pharmacol 2015; 172:3126-40. [PMID: 25684311 DOI: 10.1111/bph.13113] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/27/2015] [Accepted: 02/10/2015] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE The existence of functional K(v)7 channels in thalamocortical (TC) relay neurons and the effects of the K(+)-current termed M-current (I(M)) on thalamic signal processing have long been debated. Immunocytochemical evidence suggests their presence in this brain region. Therefore, we aimed to verify their existence, pharmacological properties and function in regulating activity in neurons of the ventrobasal thalamus (VB). EXPERIMENTAL APPROACH Characterization of K(v)7 channels was performed by combining in vitro, in vivo and in silico techniques with a pharmacological approach. Retigabine (30 μM) and XE991 (20 μM), a specific K(v)7 channel enhancer and blocker, respectively, were applied in acute brain slices during electrophysiological recordings. The effects of intrathalamic injection of retigabine (3 mM, 300 nL) and/or XE991 (2 mM, 300 nL) were investigated in freely moving animals during hot-plate tests by recording behaviour and neuronal activity. KEY RESULTS K(v)7.2 and K(v)7.3 subunits were found to be abundantly expressed in TC neurons of mouse VB. A slow K(+)-current with properties of IM was activated by retigabine and inhibited by XE991. K(v)7 channel activation evoked membrane hyperpolarization, a reduction in tonic action potential firing, and increased burst firing in vitro and in computational models. Single-unit recordings and pharmacological intervention demonstrated a specific burst-firing increase upon I(M) activation in vivo. A K(v)7 channel-mediated increase in pain threshold was associated with fewer VB units responding to noxious stimuli, and increased burst firing in responsive neurons. CONCLUSIONS AND IMPLICATIONS K(v)7 channel enhancement alters somatosensory activity and may reflect an anti-nociceptive mechanism during acute pain processing.
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Affiliation(s)
- Manuela Cerina
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
| | - Hanna J Szkudlarek
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
| | - Philippe Coulon
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
| | - Patrick Meuth
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany.,Department of Neurology, Westfälische Wilhelms-University, Münster, Germany
| | - Tatyana Kanyshkova
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
| | - Xuan Vinh Nguyen
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
| | - Kerstin Göbel
- Department of Neurology, Westfälische Wilhelms-University, Münster, Germany
| | - Thomas Seidenbecher
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
| | - Sven G Meuth
- Department of Neurology, Westfälische Wilhelms-University, Münster, Germany.,Institute of Physiology-Neuropathophysiology, Westfälische Wilhelms-University, Münster, Germany
| | - Hans-Christian Pape
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-University, Münster, Germany
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Zagha E, McCormick DA. Neural control of brain state. Curr Opin Neurobiol 2014; 29:178-86. [PMID: 25310628 DOI: 10.1016/j.conb.2014.09.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/28/2014] [Accepted: 09/13/2014] [Indexed: 11/16/2022]
Abstract
How the brain takes in information, makes a decision, and acts on this decision is strongly influenced by the ongoing and constant fluctuations of state. Understanding the nature of these brain states and how they are controlled is critical to making sense of how the nervous system operates, both normally and abnormally. While broadly projecting neuromodulatory systems acting through metabotropic pathways have long been appreciated to be critical for determining brain state, more recent investigations have revealed a prominent role for fast acting neurotransmitter pathways for temporally and spatially precise control of neural processing. Corticocortical and thalamocortical glutamatergic projections can rapidly and precisely control brain state by changing both the nature of ongoing activity and by controlling the gain and precision of neural responses.
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Affiliation(s)
- Edward Zagha
- Department of Neurobiology, Kavli Institute for Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, United States
| | - David A McCormick
- Department of Neurobiology, Kavli Institute for Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, United States.
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Abstract
Perception, cognition, and emotion do not operate along segregated pathways; rather, their adaptive interaction is supported by various sources of evidence. For instance, the aesthetic appraisal of powerful mood inducers like music can bias the facial expression of emotions towards mood congruency. In four experiments we showed similar mood-congruency effects elicited by the comfort/discomfort of body actions. Using a novel Motor Action Mood Induction Procedure, we let participants perform comfortable/uncomfortable visually-guided reaches and tested them in a facial emotion identification task. Through the alleged mediation of motor action induced mood, action comfort enhanced the quality of the participant’s global experience (a neutral face appeared happy and a slightly angry face neutral), while action discomfort made a neutral face appear angry and a slightly happy face neutral. Furthermore, uncomfortable (but not comfortable) reaching improved the sensitivity for the identification of emotional faces and reduced the identification time of facial expressions, as a possible effect of hyper-arousal from an unpleasant bodily experience.
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42
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Ortuño T, Grieve KL, Cao R, Cudeiro J, Rivadulla C. Bursting thalamic responses in awake monkey contribute to visual detection and are modulated by corticofugal feedback. Front Behav Neurosci 2014; 8:198. [PMID: 24910601 PMCID: PMC4039069 DOI: 10.3389/fnbeh.2014.00198] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 05/16/2014] [Indexed: 11/26/2022] Open
Abstract
The lateral geniculate nucleus is the gateway for visual information en route to the visual cortex. Neural activity is characterized by the existence of two firing modes: burst and tonic. Originally associated with sleep, bursts have now been postulated to be a part of the normal visual response, structured to increase the probability of cortical activation, able to act as a "wake-up" call to the cortex. We investigated a potential role for burst in the detection of novel stimuli by recording neuronal activity in the lateral geniculate nucleus (LGN) of behaving monkeys during a visual detection task. Our results show that bursts are often the neuron's first response, and are more numerous in the response to attended target stimuli than to unattended distractor stimuli. Bursts are indicators of the task novelty, as repetition decreased bursting. Because the primary visual cortex is the major modulatory input to the LGN, we compared the results obtained in control conditions with those observed when cortical activity was reduced by TMS. This cortical deactivation reduced visual response related bursting by 90%. These results highlight a novel role for the thalamus, able to code higher order image attributes as important as novelty early in the thalamo-cortical conversation.
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Affiliation(s)
- Tania Ortuño
- Neuroscience and Motor Control Group, NEUROcom, Department of Medicine, University of A CoruñaCoruña, Spain
- Biomedical Research Institute of A Coruna (INIBIC)Coruña, Spain
| | | | - Ricardo Cao
- MODES Group, Department of Mathematics, Faculty of Computer Science, University of A CoruñaCoruña, Spain
| | - Javier Cudeiro
- Neuroscience and Motor Control Group, NEUROcom, Department of Medicine, University of A CoruñaCoruña, Spain
- Biomedical Research Institute of A Coruna (INIBIC)Coruña, Spain
| | - Casto Rivadulla
- Neuroscience and Motor Control Group, NEUROcom, Department of Medicine, University of A CoruñaCoruña, Spain
- Biomedical Research Institute of A Coruna (INIBIC)Coruña, Spain
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Abstract
Awake mammals can switch between alert and nonalert brain states hundreds of times per day. Here, we study the effects of alertness on two cell classes in layer 4 of primary visual cortex of awake rabbits: presumptive excitatory "simple" cells and presumptive fast-spike inhibitory neurons (suspected inhibitory interneurons). We show that in both cell classes, alertness increases the strength and greatly enhances the reliability of visual responses. In simple cells, alertness also increases the temporal frequency bandwidth, but preserves contrast sensitivity, orientation tuning, and selectivity for direction and spatial frequency. Finally, alertness selectively suppresses the simple cell responses to high-contrast stimuli and stimuli moving orthogonal to the preferred direction, effectively enhancing mid-contrast borders. Using a population coding model, we show that these effects of alertness in simple cells--enhanced reliability, higher gain, and increased suppression in orthogonal orientation-could play a major role at increasing the speed of cortical feature detection.
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Hei X, Stoelzel CR, Zhuang J, Bereshpolova Y, Huff JM, Alonso JM, Swadlow HA. Directional selective neurons in the awake LGN: response properties and modulation by brain state. J Neurophysiol 2014; 112:362-73. [PMID: 24790175 DOI: 10.1152/jn.00121.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Directionally selective (DS) neurons are found in the retina and lateral geniculate nucleus (LGN) of rabbits and rodents, and in rabbits, LGN DS cells project to primary visual cortex. Here, we compare visual response properties of LGN DS neurons with those of layer 4 simple cells, most of which show strong direction/orientation selectivity. These populations differed dramatically, suggesting that DS cells may not contribute significantly to the synthesis of simple receptive fields: 1) whereas the first harmonic component (F1)-to-mean firing rate (F0) ratios of LGN DS cells are strongly nonlinear, those of simple cells are strongly linear; 2) whereas LGN DS cells have overlapped ON/OFF subfields, simple cells have either a single ON or OFF subfield or two spatially separate subfields; and 3) whereas the preferred directions of LGN DS cells are closely tied to the four cardinal directions, the directional preferences of simple cells are more evenly distributed. We further show that directional selectivity in LGN DS neurons is strongly enhanced by alertness via two mechanisms, 1) an increase in responses to stimulation in the preferred direction, and 2) an enhanced suppression of responses to stimuli moving in the null direction. Finally, our simulations show that these two consequences of alertness could each serve, in a vector-based population code, to hasten the computation of stimulus direction when rabbits become alert.
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Affiliation(s)
- Xiaojuan Hei
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Carl R Stoelzel
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Jun Zhuang
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Yulia Bereshpolova
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Joseph M Huff
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and
| | - Jose-Manuel Alonso
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and Department of Biological Sciences, State University of New York, New York, New York
| | - Harvey A Swadlow
- Department of Psychology, University of Connecticut, Storrs, Connecticut; and Department of Biological Sciences, State University of New York, New York, New York
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45
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Abstract
A major synaptic input to the thalamus originates from neurons in cortical layer 6 (L6); however, the function of this cortico-thalamic pathway during sensory processing is not well understood. In the mouse whisker system, we found that optogenetic stimulation of L6 in vivo results in a mixture of hyperpolarization and depolarization in the thalamic target neurons. The hyperpolarization was transient, and for longer L6 activation (>200 ms), thalamic neurons reached a depolarized resting membrane potential which affected key features of thalamic sensory processing. Most importantly, L6 stimulation reduced the adaptation of thalamic responses to repetitive whisker stimulation, thereby allowing thalamic neurons to relay higher frequencies of sensory input. Furthermore, L6 controlled the thalamic response mode by shifting thalamo-cortical transmission from bursting to single spiking. Analysis of intracellular sensory responses suggests that L6 impacts these thalamic properties by controlling the resting membrane potential and the availability of the transient calcium current IT, a hallmark of thalamic excitability. In summary, L6 input to the thalamus can shape both the overall gain and the temporal dynamics of sensory responses that reach the cortex.
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46
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Cumulative latency advance underlies fast visual processing in desynchronized brain state. Proc Natl Acad Sci U S A 2013; 111:515-20. [PMID: 24347634 DOI: 10.1073/pnas.1316166111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fast sensory processing is vital for the animal to efficiently respond to the changing environment. This is usually achieved when the animal is vigilant, as reflected by cortical desynchronization. However, the neural substrate for such fast processing remains unclear. Here, we report that neurons in rat primary visual cortex (V1) exhibited shorter response latency in the desynchronized state than in the synchronized state. In vivo whole-cell recording from the same V1 neurons undergoing the two states showed that both the resting and visually evoked conductances were higher in the desynchronized state. Such conductance increases of single V1 neurons shorten the response latency by elevating the membrane potential closer to the firing threshold and reducing the membrane time constant, but the effects only account for a small fraction of the observed latency advance. Simultaneous recordings in lateral geniculate nucleus (LGN) and V1 revealed that LGN neurons also exhibited latency advance, with a degree smaller than that of V1 neurons. Furthermore, latency advance in V1 increased across successive cortical layers. Thus, latency advance accumulates along various stages of the visual pathway, likely due to a global increase of membrane conductance in the desynchronized state. This cumulative effect may lead to a dramatic shortening of response latency for neurons in higher visual cortex and play a critical role in fast processing for vigilant animals.
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47
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Bosch-Bouju C, Hyland BI, Parr-Brownlie LC. Motor thalamus integration of cortical, cerebellar and basal ganglia information: implications for normal and parkinsonian conditions. Front Comput Neurosci 2013; 7:163. [PMID: 24273509 PMCID: PMC3822295 DOI: 10.3389/fncom.2013.00163] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/24/2013] [Indexed: 12/23/2022] Open
Abstract
Motor thalamus (Mthal) is implicated in the control of movement because it is strategically located between motor areas of the cerebral cortex and motor-related subcortical structures, such as the cerebellum and basal ganglia (BG). The role of BG and cerebellum in motor control has been extensively studied but how Mthal processes inputs from these two networks is unclear. Specifically, there is considerable debate about the role of BG inputs on Mthal activity. This review summarizes anatomical and physiological knowledge of the Mthal and its afferents and reviews current theories of Mthal function by discussing the impact of cortical, BG and cerebellar inputs on Mthal activity. One view is that Mthal activity in BG and cerebellar-receiving territories is primarily "driven" by glutamatergic inputs from the cortex or cerebellum, respectively, whereas BG inputs are modulatory and do not strongly determine Mthal activity. This theory is steeped in the assumption that the Mthal processes information in the same way as sensory thalamus, through interactions of modulatory inputs with a single driver input. Another view, from BG models, is that BG exert primary control on the BG-receiving Mthal so it effectively relays information from BG to cortex. We propose a new "super-integrator" theory where each Mthal territory processes multiple driver or driver-like inputs (cortex and BG, cortex and cerebellum), which are the result of considerable integrative processing. Thus, BG and cerebellar Mthal territories assimilate motivational and proprioceptive motor information previously integrated in cortico-BG and cortico-cerebellar networks, respectively, to develop sophisticated motor signals that are transmitted in parallel pathways to cortical areas for optimal generation of motor programmes. Finally, we briefly review the pathophysiological changes that occur in the BG in parkinsonism and generate testable hypotheses about how these may affect processing of inputs in the Mthal.
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Affiliation(s)
- Clémentine Bosch-Bouju
- 1Department of Anatomy, Otago School of Medical Science, University of Otago Dunedin, New Zealand ; 2Brain Health Research Centre, Otago School of Medical Science, University of Otago Dunedin, New Zealand
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48
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Pinto L, Goard MJ, Estandian D, Xu M, Kwan AC, Lee SH, Harrison TC, Feng G, Dan Y. Fast modulation of visual perception by basal forebrain cholinergic neurons. Nat Neurosci 2013; 16:1857-1863. [PMID: 24162654 PMCID: PMC4201942 DOI: 10.1038/nn.3552] [Citation(s) in RCA: 369] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 09/18/2013] [Indexed: 12/14/2022]
Abstract
The basal forebrain provides the primary source of cholinergic input to the cortex, and it has a crucial function in promoting wakefulness and arousal. However, whether rapid changes in basal forebrain neuron spiking in awake animals can dynamically influence sensory perception is unclear. Here we show that basal forebrain cholinergic neurons rapidly regulate cortical activity and visual perception in awake, behaving mice. Optogenetic activation of the cholinergic neurons or their V1 axon terminals improved performance of a visual discrimination task on a trial-by-trial basis. In V1, basal forebrain activation enhanced visual responses and desynchronized neuronal spiking; these changes could partly account for the behavioral improvement. Conversely, optogenetic basal forebrain inactivation decreased behavioral performance, synchronized cortical activity and impaired visual responses, indicating the importance of cholinergic activity in normal visual processing. These results underscore the causal role of basal forebrain cholinergic neurons in fast, bidirectional modulation of cortical processing and sensory perception.
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Affiliation(s)
- Lucas Pinto
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Michael J Goard
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Daniel Estandian
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Min Xu
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Alex C Kwan
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Seung-Hee Lee
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Thomas C Harrison
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Guoping Feng
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Yang Dan
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
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49
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Layer 4 in primary visual cortex of the awake rabbit: contrasting properties of simple cells and putative feedforward inhibitory interneurons. J Neurosci 2013; 33:11372-89. [PMID: 23843510 DOI: 10.1523/jneurosci.0863-13.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Extracellular recordings were obtained from two cell classes in layer 4 of the awake rabbit primary visual cortex (V1): putative inhibitory interneurons [suspected inhibitory interneurons (SINs)] and putative excitatory cells with simple receptive fields. SINs were identified solely by their characteristic response to electrical stimulation of the lateral geniculate nucleus (LGN, 3+ spikes at >600 Hz), and simple cells were identified solely by receptive field structure, requiring spatially separate ON and/or OFF subfields. Notably, no cells met both criteria, and we studied 62 simple cells and 33 SINs. Fourteen cells met neither criterion. These layer 4 populations were markedly distinct. Thus, SINs were far less linear (F1/F0 < 1), more broadly tuned to stimulus orientation, direction, spatial and temporal frequency, more sensitive to contrast, had much higher spontaneous and stimulus-driven activity, and always had spatially overlapping ON/OFF receptive subfields. SINs responded to drifting gratings with increased firing rates (F0) for all orientations and directions. However, some SINs showed a weaker modulated (F1) response sharply tuned to orientation and/or direction. SINs responded at shorter latencies than simple cells to stationary stimuli, and the responses of both populations could be sustained or transient. Transient simple cells were more sensitive to contrast than sustained simple cells and their visual responses were more frequently suppressed by high contrasts. Finally, cross-correlation between LGN and SIN spike trains confirmed a fast and precisely timed monosynaptic connectivity, supporting the notion that SINs are well suited to provide a fast feedforward inhibition onto targeted cortical populations.
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50
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Woods AJ, Philbeck JW, Wirtz P. Hyper-arousal decreases human visual thresholds. PLoS One 2013; 8:e61415. [PMID: 23593478 PMCID: PMC3620239 DOI: 10.1371/journal.pone.0061415] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 03/13/2013] [Indexed: 11/18/2022] Open
Abstract
Arousal has long been known to influence behavior and serves as an underlying component of cognition and consciousness. However, the consequences of hyper-arousal for visual perception remain unclear. The present study evaluates the impact of hyper-arousal on two aspects of visual sensitivity: visual stereoacuity and contrast thresholds. Sixty-eight participants participated in two experiments. Thirty-four participants were randomly divided into two groups in each experiment: Arousal Stimulation or Sham Control. The Arousal Stimulation group underwent a 50-second cold pressor stimulation (immersing the foot in 0-2° C water), a technique known to increase arousal. In contrast, the Sham Control group immersed their foot in room temperature water. Stereoacuity thresholds (Experiment 1) and contrast thresholds (Experiment 2) were measured before and after stimulation. The Arousal Stimulation groups demonstrated significantly lower stereoacuity and contrast thresholds following cold pressor stimulation, whereas the Sham Control groups showed no difference in thresholds. These results provide the first evidence that hyper-arousal from sensory stimulation can lower visual thresholds. Hyper-arousal's ability to decrease visual thresholds has important implications for survival, sports, and everyday life.
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Affiliation(s)
- Adam J Woods
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
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