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Margalit SN, Slovin H. Spatio-temporal activation patterns of neuronal population evoked by optostimulation and the comparison to electrical microstimulation. Sci Rep 2023; 13:12689. [PMID: 37542091 PMCID: PMC10403613 DOI: 10.1038/s41598-023-39808-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 07/31/2023] [Indexed: 08/06/2023] Open
Abstract
Optostimulation and electrical microstimulation are well-established techniques that enable to artificially stimulate the brain. While the activation patterns evoked by microstimulation in cortical network are well characterized, much less is known for optostimulation. Specifically, the activation maps of neuronal population at the membrane potential level and direct measurements of these maps were barely reported. In addition, only a few studies compared the activation patterns evoked by microstimulation and optostimulation. In this study we addressed these issues by applying optostimulation in the barrel cortex of anesthetized rats after a short (ShortExp) or a long (LongExp) opsin expression time and compared it to microstimulation. We measured the membrane potential of neuronal populations at high spatial (meso-scale) and temporal resolution using voltage-sensitive dye imaging. Longer optostimulation pulses evoked higher neural responses spreading over larger region relative to short pulses. Interestingly, similar optostimulation pulses evoked stronger and more prolonged population response in the LongExp vs. the ShortExp condition. Finally, the spatial activation patterns evoked in the LongExp condition showed an intermediate state, with higher resemblance to the microstimulation at the stimulation site. Therefore, short microstimulation and optostimulation can induce wide spread activation, however the effects of optostimulation depend on the opsin expression time.
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Affiliation(s)
| | - Hamutal Slovin
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.
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2
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Bundy DT, Barbay S, Hudson HM, Frost SB, Nudo RJ, Guggenmos DJ. Stimulation-Evoked Effective Connectivity (SEEC): An in-vivo approach for defining mesoscale corticocortical connectivity. J Neurosci Methods 2023; 384:109767. [PMID: 36493978 DOI: 10.1016/j.jneumeth.2022.109767] [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: 07/11/2022] [Revised: 11/07/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND Cortical electrical stimulation is a versatile technique for examining the structure and function of cortical regions and for implementing novel therapies. While electrical stimulation has been used to examine the local spread of neural activity, it may also enable longitudinal examination of mesoscale interregional connectivity. NEW METHOD Here, we sought to use intracortical microstimulation (ICMS) in conjunction with recordings of multi-unit action potentials to assess the mesoscale effective connectivity within sensorimotor cortex. Neural recordings were made from multielectrode arrays placed into sensory, motor, and premotor regions during surgical experiments in three squirrel monkeys. During each recording, single-pulse ICMS was repeatably delivered to a single region. Mesoscale effective connectivity was calculated from ICMS-evoked changes in multi-unit firing. RESULTS Multi-unit action potentials were able to be detected on the order of 1 ms after each ICMS pulse. Across sensorimotor regions, short-latency (< 2.5 ms) ICMS-evoked neural activity strongly correlated with known anatomical connections. Additionally, ICMS-evoked responses remained stable across the experimental period, despite small changes in electrode locations and anesthetic state. COMPARISON WITH EXISTING METHODS Previous imaging studies investigating cross-regional responses to stimulation are limited to utilizing indirect hemodynamic responses and thus lack the temporal specificity of ICMS-evoked responses. CONCLUSIONS These results show that monitoring ICMS-evoked neural activity, in a technique we refer to as Stimulation-Evoked Effective Connectivity (SEEC), is a viable way to longitudinally assess effective connectivity, enabling studies comparing the time course of connectivity changes with the time course of changes in behavioral function.
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Affiliation(s)
- David T Bundy
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Scott Barbay
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Heather M Hudson
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Shawn B Frost
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Randolph J Nudo
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA; Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA.
| | - David J Guggenmos
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
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3
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Borden PY, Wright NC, Morrissette AE, Jaeger D, Haider B, Stanley GB. Thalamic bursting and the role of timing and synchrony in thalamocortical signaling in the awake mouse. Neuron 2022; 110:2836-2853.e8. [PMID: 35803270 PMCID: PMC9464711 DOI: 10.1016/j.neuron.2022.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 03/04/2022] [Accepted: 06/07/2022] [Indexed: 11/30/2022]
Abstract
The thalamus controls transmission of sensory signals from periphery to cortex, ultimately shaping perception. Despite this significant role, dynamic thalamic gating and the consequences for downstream cortical sensory representations have not been well studied in the awake brain. We optogenetically modulated the ventro-posterior-medial thalamus in the vibrissa pathway of the awake mouse and measured spiking activity in the thalamus and activity in primary somatosensory cortex (S1) using extracellular electrophysiology and genetically encoded voltage imaging. Thalamic hyperpolarization significantly enhanced thalamic sensory-evoked bursting; however, surprisingly, the S1 cortical response was not amplified, but instead, timing precision was significantly increased, spatial activation more focused, and there was an increased synchronization of cortical inhibitory neurons. A thalamocortical network model implicates the modulation of precise timing of feedforward thalamic population spiking, presenting a highly sensitive, timing-based gating of sensory signaling to the cortex.
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Affiliation(s)
- Peter Y Borden
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA 30332, USA
| | - Nathaniel C Wright
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA 30332, USA
| | | | - Dieter Jaeger
- Emory University, Department of Biology, Atlanta, GA 30322, USA
| | - Bilal Haider
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA 30332, USA
| | - Garrett B Stanley
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA 30332, USA.
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4
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Abstract
Brain state fluctuates throughout the course of the day. Whether and how these fluctuations impact signal propagation in the brain remains unknown. Here, we used optogenetic stimulation during different brain states to show that the coupling between neurons modulates the spread of signals across cortical circuits in a state-dependent manner. Our results indicate that brain state influences how far electrical signals travel in neocortex and suggest a revision of computational models relying on robust signal propagation across neural networks. Our perception of the environment relies on the efficient propagation of neural signals across cortical networks. During the time course of a day, neural responses fluctuate dramatically as the state of the brain changes to possibly influence how electrical signals propagate across neural circuits. Despite the importance of this issue, how patterns of spiking activity propagate within neuronal circuits in different brain states remains unknown. Here, we used multielectrode laminar arrays to reveal that brain state strongly modulates the propagation of neural activity across the layers of early visual cortex (V1). We optogenetically induced synchronized state transitions within a group of neurons and examined how far electrical signals travel during wakefulness and rest. Although optogenetic stimulation elicits stronger neural responses during wakefulness relative to rest, signals propagate only weakly across the cortical column during wakefulness, and the extent of spread is inversely related to arousal level. In contrast, the light-induced population activity vigorously propagates throughout the entire cortical column during rest, even when neurons are in a desynchronized wake-like state prior to light stimulation. Mechanistically, the influence of global brain state on the propagation of spiking activity across laminar circuits can be explained by state-dependent changes in the coupling between neurons. Our results impose constraints on the conclusions of causal manipulation studies attempting to influence neural function and behavior, as well as on previous computational models of perception assuming robust signal propagation across cortical layers and areas.
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5
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Bolus MF, Willats AA, Rozell CJ, Stanley GB. State-space optimal feedback control of optogenetically driven neural activity. J Neural Eng 2021; 18. [PMID: 32932241 DOI: 10.1088/1741-2552/abb89c] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 09/15/2020] [Indexed: 11/11/2022]
Abstract
Objective.The rapid acceleration of tools for recording neuronal populations and targeted optogenetic manipulation has enabled real-time, feedback control of neuronal circuits in the brain. Continuously-graded control of measured neuronal activity poses a wide range of technical challenges, which we address through a combination of optogenetic stimulation and a state-space optimal control framework implemented in the thalamocortical circuit of the awake mouse.Approach.Closed-loop optogenetic control of neurons was performed in real-time via stimulation of channelrhodopsin-2 expressed in the somatosensory thalamus of the head-fixed mouse. A state-space linear dynamical system model structure was used to approximate the light-to-spiking input-output relationship in both single-neuron as well as multi-neuron scenarios when recording from multielectrode arrays. These models were utilized to design state feedback controller gains by way of linear quadratic optimal control and were also used online for estimation of state feedback, where a parameter-adaptive Kalman filter provided robustness to model-mismatch.Main results.This model-based control scheme proved effective for feedback control of single-neuron firing rate in the thalamus of awake animals. Notably, the graded optical actuation utilized here did not synchronize simultaneously recorded neurons, but heterogeneity across the neuronal population resulted in a varied response to stimulation. Simulated multi-output feedback control provided better control of a heterogeneous population and demonstrated how the approach generalizes beyond single-neuron applications.Significance.To our knowledge, this work represents the first experimental application of state space model-based feedback control for optogenetic stimulation. In combination with linear quadratic optimal control, the approaches laid out and tested here should generalize to future problems involving the control of highly complex neural circuits. More generally, feedback control of neuronal circuits opens the door to adaptively interacting with the dynamics underlying sensory, motor, and cognitive signaling, enabling a deeper understanding of circuit function and ultimately the control of function in the face of injury or disease.
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Affiliation(s)
- M F Bolus
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States of America
| | - A A Willats
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States of America
| | - C J Rozell
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States of America
| | - G B Stanley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States of America
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6
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Caldwell DJ, Ojemann JG, Rao RPN. Direct Electrical Stimulation in Electrocorticographic Brain-Computer Interfaces: Enabling Technologies for Input to Cortex. Front Neurosci 2019; 13:804. [PMID: 31440127 PMCID: PMC6692891 DOI: 10.3389/fnins.2019.00804] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/18/2019] [Indexed: 12/22/2022] Open
Abstract
Electrocorticographic brain computer interfaces (ECoG-BCIs) offer tremendous opportunities for restoring function in individuals suffering from neurological damage and for advancing basic neuroscience knowledge. ECoG electrodes are already commonly used clinically for monitoring epilepsy and have greater spatial specificity in recording neuronal activity than techniques such as electroencephalography (EEG). Much work to date in the field has focused on using ECoG signals recorded from cortex as control outputs for driving end effectors. An equally important but less explored application of an ECoG-BCI is directing input into cortex using ECoG electrodes for direct electrical stimulation (DES). Combining DES with ECoG recording enables a truly bidirectional BCI, where information is both read from and written to the brain. We discuss the advantages and opportunities, as well as the barriers and challenges presented by using DES in an ECoG-BCI. In this article, we review ECoG electrodes, the physics and physiology of DES, and the use of electrical stimulation of the brain for the clinical treatment of disorders such as epilepsy and Parkinson’s disease. We briefly discuss some of the translational, regulatory, financial, and ethical concerns regarding ECoG-BCIs. Next, we describe the use of ECoG-based DES for providing sensory feedback and for probing and modifying cortical connectivity. We explore future directions, which may draw on invasive animal studies with penetrating and surface electrodes as well as non-invasive stimulation methods such as transcranial magnetic stimulation (TMS). We conclude by describing enabling technologies, such as smaller ECoG electrodes for more precise targeting of cortical areas, signal processing strategies for simultaneous stimulation and recording, and computational modeling and algorithms for tailoring stimulation to each individual brain.
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Affiliation(s)
- David J Caldwell
- Department of Bioengineering, University of Washington, Seattle, WA, United States.,Medical Scientist Training Program, University of Washington, Seattle, WA, United States.,Center for Neurotechnology, University of Washington, Seattle, WA, United States
| | - Jeffrey G Ojemann
- Center for Neurotechnology, University of Washington, Seattle, WA, United States.,Department of Neurological Surgery, University of Washington, Seattle, WA, United States
| | - Rajesh P N Rao
- Department of Bioengineering, University of Washington, Seattle, WA, United States.,Center for Neurotechnology, University of Washington, Seattle, WA, United States.,Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, United States
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7
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Dadarlat MC, Sun Y, Stryker MP. Widespread activation of awake mouse cortex by electrical stimulation. INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING : [PROCEEDINGS]. INTERNATIONAL IEEE EMBS CONFERENCE ON NEURAL ENGINEERING 2019; 2019:1113-1117. [PMID: 31363384 DOI: 10.1109/ner.2019.8716956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Electrical stimulation is a highly-effective, temporally-precise technique to evoke neural activity in the brain, and thus is critically important for both research and clinical applications. Here, we set out to understand the time-course and spatial spread of neural activation elicited by electrical stimulation. By imaging the cortex of awake, chronically-implanted, transgenic mice during electrical stimulation, we found that a broad range of stimulation parameters led to widespread neural activation. In general, increasing current amplitude and the number of stimulation pulses progressively produced higher maximum activity and activated larger areas of cortex. However, increasing stimulation frequency above 30 Hz primarily shifted the timing, not amplitude, of peak activity. Our results demonstrate that even weak electrical stimulation widely activates neurons within awake mouse cortex.
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Affiliation(s)
- Maria C Dadarlat
- Physiology Department at the University of California - San Francisco, 675 Nelson Rising Lane, Room 436 San Francisco, CA 94158
| | - Yujiao Sun
- Physiology Department at the University of California - San Francisco, 675 Nelson Rising Lane, Room 436 San Francisco, CA 94158
| | - Michael P Stryker
- Physiology Department at the University of California - San Francisco, 675 Nelson Rising Lane, Room 436 San Francisco, CA 94158
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8
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Caldwell DJ, Cronin JA, Wu J, Weaver KE, Ko AL, Rao RPN, Ojemann JG. Direct stimulation of somatosensory cortex results in slower reaction times compared to peripheral touch in humans. Sci Rep 2019; 9:3292. [PMID: 30824821 PMCID: PMC6397274 DOI: 10.1038/s41598-019-38619-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 01/04/2019] [Indexed: 01/13/2023] Open
Abstract
Direct cortical stimulation (DCS) of primary somatosensory cortex (S1) could help restore sensation and provide task-relevant feedback in a neuroprosthesis. However, the psychophysics of S1 DCS is poorly studied, including any comparison to cutaneous haptic stimulation. We compare the response times to DCS of human hand somatosensory cortex through electrocorticographic grids with response times to haptic stimuli delivered to the hand in four subjects. We found that subjects respond significantly slower to S1 DCS than to natural, haptic stimuli for a range of DCS train durations. Median response times for haptic stimulation varied from 198 ms to 313 ms, while median responses to reliably perceived DCS ranged from 254 ms for one subject, all the way to 528 ms for another. We discern no significant impact of learning or habituation through the analysis of blocked trials, and find no significant impact of cortical stimulation train duration on response times. Our results provide a realistic set of expectations for latencies with somatosensory DCS feedback for future neuroprosthetic applications and motivate the study of neural mechanisms underlying human perception of somatosensation via DCS.
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Affiliation(s)
- David J Caldwell
- Department of Bioengineering, University of Washington, Seattle, USA. .,Medical Scientist Training Program, University of Washington, Seattle, USA. .,National Science Foundation Center for Neurotechnology, Seattle, USA.
| | - Jeneva A Cronin
- Department of Bioengineering, University of Washington, Seattle, USA. .,National Science Foundation Center for Neurotechnology, Seattle, USA.
| | - Jing Wu
- Department of Bioengineering, University of Washington, Seattle, USA.,National Science Foundation Center for Neurotechnology, Seattle, USA
| | - Kurt E Weaver
- Department of Radiology, University of Washington, Seattle, USA.,National Science Foundation Center for Neurotechnology, Seattle, USA
| | - Andrew L Ko
- Department of Neurological Surgery, University of Washington, Seattle, USA.,National Science Foundation Center for Neurotechnology, Seattle, USA
| | - Rajesh P N Rao
- Department of Computer Science and Engineering, University of Washington, Seattle, USA.,National Science Foundation Center for Neurotechnology, Seattle, USA
| | - Jeffrey G Ojemann
- Department of Neurological Surgery, University of Washington, Seattle, USA.,National Science Foundation Center for Neurotechnology, Seattle, USA
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9
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Hippocampal Lateralization and Synaptic Plasticity in the Intact Rat: No Left-Right Asymmetry in Electrically Induced CA3-CA1 Long-Term Potentiation. Neuroscience 2018; 397:147-158. [PMID: 30513373 PMCID: PMC6347473 DOI: 10.1016/j.neuroscience.2018.11.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/23/2018] [Accepted: 11/28/2018] [Indexed: 12/24/2022]
Abstract
The hippocampus is not a unitary, homogeneous brain area. Anatomical and functional specialization is evident along the septotemporal axis of the structure, and between the left and right hemispheres. In the mouse brain, a left-right asymmetry has been discovered in the plasticity of CA3-CA1 projections originating in the left versus right hippocampus. Presynaptic afferents originating in the left hemisphere-including both uncrossed Schaffer collaterals, and crossed commissural projections to the contralateral CA1-form small, plastic synapses, whereas afferents originating in right CA3 contact larger, less plastic, synapses. Studies using optogenetic techniques to selectively activate fibers originating from one hemisphere in ex vivo slices have revealed that projections originating from left CA3 exhibit a far greater capacity for long-term potentiation (LTP) of synaptic strength than those originating on the right. However, corresponding data from rats are currently unavailable, leaving open the question of species differences in hippocampal symmetry. In the current study, we reanalyzed data from our previous in vivo LTP work to address this issue. We analyzed plasticity in independent Schaffer collateral and commissural projections to CA1 originating from left and right CA3 in male Lister-hooded rats. However, we found no differences in the magnitude and duration of LTP induced in either crossed or uncrossed pathways following high-frequency tetanization of left versus right CA3. This contrast with previous findings may stem from methodological differences between in vivo electrical and ex vivo optogenetic approaches, but may reflect a genuine species difference in the organization and laterality of the rodent CA3-CA1 system.
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10
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Spatio-temporal characteristics of population responses evoked by microstimulation in the barrel cortex. Sci Rep 2018; 8:13913. [PMID: 30224723 PMCID: PMC6141467 DOI: 10.1038/s41598-018-32148-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/03/2018] [Indexed: 11/09/2022] Open
Abstract
Intra-cortical microstimulation (ICMS) is a widely used technique to artificially stimulate cortical tissue. This method revealed functional maps and provided causal links between neuronal activity and cognitive, sensory or motor functions. The effects of ICMS on neural activity depend on stimulation parameters. Past studies investigated the effects of stimulation frequency mainly at the behavioral or motor level. Therefore the direct effect of frequency stimulation on the evoked spatio-temporal patterns of cortical activity is largely unknown. To study this question we used voltage-sensitive dye imaging to measure the population response in the barrel cortex of anesthetized rats evoked by high frequency stimulation (HFS), a lower frequency stimulation (LFS) of the same duration or a single pulse stimulation. We found that single pulse and short trains of ICMS induced cortical activity extending over few mm. HFS evoked a lower population response during the sustained response and showed a smaller activation across time and space compared with LFS. Finally the evoked population response started near the electrode site and spread horizontally at a propagation velocity in accordance with horizontal connections. In summary, HFS was less effective in cortical activation compared to LFS although HFS had 5 fold more energy than LFS.
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11
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Kyriakatos A, Sadashivaiah V, Zhang Y, Motta A, Auffret M, Petersen CCH. Voltage-sensitive dye imaging of mouse neocortex during a whisker detection task. NEUROPHOTONICS 2017; 4:031204. [PMID: 27921068 PMCID: PMC5120151 DOI: 10.1117/1.nph.4.3.031204] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 10/19/2016] [Indexed: 06/06/2023]
Abstract
Sensorimotor processing occurs in a highly distributed manner in the mammalian neocortex. The spatiotemporal dynamics of electrical activity in the dorsal mouse neocortex can be imaged using voltage-sensitive dyes (VSDs) with near-millisecond temporal resolution and [Formula: see text] spatial resolution. Here, we trained mice to lick a water reward spout after a 1-ms deflection of the C2 whisker, and we imaged cortical dynamics during task execution with VSD RH1691. Responses to whisker deflection were highly dynamic and spatially highly distributed, exhibiting high variability from trial to trial in amplitude and spatiotemporal dynamics. We differentiated trials based on licking and whisking behavior. Hit trials, in which the mouse licked after the whisker stimulus, were accompanied by overall greater depolarization compared to miss trials, with the strongest hit versus miss differences being found in frontal cortex. Prestimulus whisking decreased behavioral performance by increasing the fraction of miss trials, and these miss trials had attenuated cortical sensorimotor responses. Our data suggest that the spatiotemporal dynamics of depolarization in mouse sensorimotor cortex evoked by a single brief whisker deflection are subject to important behavioral modulation during the execution of a simple, learned, goal-directed sensorimotor transformation.
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12
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Whitmire CJ, Millard DC, Stanley GB. Thalamic state control of cortical paired-pulse dynamics. J Neurophysiol 2017; 117:163-177. [PMID: 27760816 PMCID: PMC5209547 DOI: 10.1152/jn.00415.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/15/2016] [Indexed: 11/22/2022] Open
Abstract
Sensory stimulation drives complex interactions across neural circuits as information is encoded and then transmitted from one brain region to the next. In the highly interconnected thalamocortical circuit, these complex interactions elicit repeatable neural dynamics in response to temporal patterns of stimuli that provide insight into the circuit properties that generated them. Here, using a combination of in vivo voltage-sensitive dye (VSD) imaging of cortex, single-unit recording in thalamus, and optogenetics to manipulate thalamic state in the rodent vibrissa pathway, we probed the thalamocortical circuit with simple temporal patterns of stimuli delivered either to the whiskers on the face (sensory stimulation) or to the thalamus directly via electrical or optogenetic inputs (artificial stimulation). VSD imaging of cortex in response to whisker stimulation revealed classical suppressive dynamics, while artificial stimulation of thalamus produced an additional facilitation dynamic in cortex not observed with sensory stimulation. Thalamic neurons showed enhanced bursting activity in response to artificial stimulation, suggesting that bursting dynamics may underlie the facilitation mechanism we observed in cortex. To test this experimentally, we directly depolarized the thalamus, using optogenetic modulation of the firing activity to shift from a burst to a tonic mode. In the optogenetically depolarized thalamic state, the cortical facilitation dynamic was completely abolished. Together, the results obtained here from simple probes suggest that thalamic state, and ultimately thalamic bursting, may play a key role in shaping more complex stimulus-evoked dynamics in the thalamocortical pathway. NEW & NOTEWORTHY For the first time, we have been able to utilize optogenetic modulation of thalamic firing modes combined with optical imaging of cortex in the rat vibrissa system to directly test the role of thalamic state in shaping cortical response properties.
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Affiliation(s)
- Clarissa J Whitmire
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Daniel C Millard
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Garrett B Stanley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
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13
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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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14
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Abstract
Adaptation is fundamental to life. All organisms adapt over timescales that span from evolution to generations and lifetimes to moment-by-moment interactions. The nervous system is particularly adept at rapidly adapting to change, and this in fact may be one of its fundamental principles of organization and function. Rapid forms of sensory adaptation have been well documented across all sensory modalities in a wide range of organisms, yet we do not have a comprehensive understanding of the adaptive cellular mechanisms that ultimately give rise to the corresponding percepts, due in part to the complexity of the circuitry. In this Perspective, we aim to build links between adaptation at multiple scales of neural circuitry by investigating the differential adaptation across brain regions and sub-regions and across specific cell types, for which the explosion of modern tools has just begun to enable. This investigation points to a set of challenges for the field to link functional observations to adaptive properties of the neural circuit that ultimately underlie percepts.
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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
| | - 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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15
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Sarter M, Lustig C, Berry AS, Gritton H, Howe WM, Parikh V. What do phasic cholinergic signals do? Neurobiol Learn Mem 2016; 130:135-41. [PMID: 26911787 DOI: 10.1016/j.nlm.2016.02.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/10/2016] [Accepted: 02/12/2016] [Indexed: 12/16/2022]
Abstract
In addition to the neuromodulatory role of cholinergic systems, brief, temporally discrete cholinergic release events, or "transients", have been associated with the detection of cues in attention tasks. Here we review four main findings about cholinergic transients during cognitive processing. Cholinergic transients are: (1) associated with the detection of a cue and influenced by cognitive state; (2) not dependent on reward outcome, although the timing of the transient peak co-varies with the temporal relationship between detection and reward delivery; (3) correlated with the mobilization of the cue-evoked response; (4) causal mediators of shifts from monitoring to cue detection. We next discuss some of the key questions concerning the timing and occurrence of transients within the framework of available evidence including: (1) Why does the shift from monitoring to cue detection require a transient? (2) What determines whether a cholinergic transient will be generated? (3) How can cognitive state influence transient occurrence? (4) Why do cholinergic transients peak at around the time of reward delivery? (5) Is there evidence of cholinergic transients in humans? We conclude by outlining future research studies necessary to more fully understand the role of cholinergic transients in mediating cue detection.
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Affiliation(s)
- Martin Sarter
- University of Michigan, Dept. of Psychology and Neuroscience Program, Ann Arbor, MI, United States.
| | - Cindy Lustig
- University of Michigan, Dept. of Psychology and Neuroscience Program, Ann Arbor, MI, United States.
| | - Anne S Berry
- Lawrence Berkeley National Laboratory, UC Berkeley, Berkeley, CA, United States
| | - Howard Gritton
- Boston University, Dept. of Biomedical Engineering, Boston, MA, United States
| | - William M Howe
- Boston University, Dept. of Biomedical Engineering, Boston, MA, United States; Pfizer Neuroscience, Cambridge, MA, United States
| | - Vinay Parikh
- Temple University, Dept. of Psychology and Neuroscience Program, Philadelphia, PA, United States
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