scholarly journals Early fMRI responses to somatosensory and optogenetic stimulation reflect neural information flow

2021 ◽  
Vol 118 (11) ◽  
pp. e2023265118
Author(s):  
Won Beom Jung ◽  
Geun Ho Im ◽  
Haiyan Jiang ◽  
Seong-Gi Kim
Keyword(s):  
Information Flow ◽  
Bold Response ◽  
Cortical Layers ◽  
Spatiotemporal Resolution ◽  
Somatosensory Stimulation ◽  
Network Analyses ◽  
Brain Functions ◽  
Optogenetic Stimulation ◽  
Bold Responses ◽  
Stimulation Of

Blood oxygenation level–dependent (BOLD) functional magnetic resonance imaging (fMRI) has been widely used to localize brain functions. To further advance understanding of brain functions, it is critical to understand the direction of information flow, such as thalamocortical versus corticothalamic projections. For this work, we performed ultrahigh spatiotemporal resolution fMRI at 15.2 T of the mouse somatosensory network during forepaw somatosensory stimulation and optogenetic stimulation of the primary motor cortex (M1). Somatosensory stimulation induced the earliest BOLD response in the ventral posterolateral nucleus (VPL), followed by the primary somatosensory cortex (S1) and then M1 and posterior thalamic nucleus. Optogenetic stimulation of excitatory neurons in M1 induced the earliest BOLD response in M1, followed by S1 and then VPL. Within S1, the middle cortical layers responded to somatosensory stimulation earlier than the upper or lower layers, whereas the upper cortical layers responded earlier than the other two layers to optogenetic stimulation in M1. The order of early BOLD responses was consistent with the canonical understanding of somatosensory network connections and cannot be explained by regional variabilities in the hemodynamic response functions measured using hypercapnic stimulation. Our data demonstrate that early BOLD responses reflect the information flow in the mouse somatosensory network, suggesting that high-field fMRI can be used for systems-level network analyses.

scholarly journals Modification of oxygen consumption and blood flow in mouse somatosensory cortex by cell-type-specific neuronal activity

2019 ◽  
Author(s):  
Matilda Dahlqvist ◽  
Kirsten Thomsen ◽  
Dmitry Postnov ◽  
Martin Lauritzen
Keyword(s):  
Neuronal Activity ◽  
Pyramidal Neurons ◽  
Rhythmic Activity ◽  
Inhibitory Neurons ◽  
Gamma Activity ◽  
Somatosensory Stimulation ◽  
Neuronal Excitation ◽  
Optogenetic Stimulation ◽  
Higher Cognitive Functions ◽  
Stimulation Of

AbstractGamma activity arises from the interplay between pyramidal neurons and fast-spiking parvalbumin (PV) interneurons, is an integral part of higher cognitive functions and is assumed to contribute importantly to brain metabolic responses. Cerebral metabolic rate of oxygen (CMRO2) responses were evoked by optogenetic stimulation of cortical PV interneurons and pyramidal neurons. We found that CMRO2 responses depended on neuronal activation, but not on the power of gamma activity induced by optogenetic stimulation. This implies that evoked gamma activity per se is not energy demanding. Optogenetic stimulation of PV interneurons during somatosensory stimulation reduced excitatory neuronal activity but did not potentiate O2 consumption as previously hypothesized. In conclusion, our data suggest that activity-driven CMRO2 responses depend on neuronal excitation rather than the cerebral rhythmic activity they induce. Excitation of both excitatory and inhibitory neurons requires energy, but inhibition of cortical excitatory neurons by interneurons does not potentiate activity-driven energy consumption.

scholarly journals Modification of oxygen consumption and blood flow in mouse somatosensory cortex by cell-type-specific neuronal activity

2019 ◽  
Vol 40 (10) ◽  
pp. 2010-2025 ◽  
Author(s):  
Matilda K Dahlqvist ◽  
Kirsten J Thomsen ◽  
Dmitry D Postnov ◽  
Martin J Lauritzen
Keyword(s):  
Neuronal Activity ◽  
Pyramidal Neurons ◽  
Rhythmic Activity ◽  
Inhibitory Neurons ◽  
Gamma Activity ◽  
Somatosensory Stimulation ◽  
Neuronal Excitation ◽  
Optogenetic Stimulation ◽  
Higher Cognitive Functions ◽  
Stimulation Of

Gamma activity arising from the interplay between pyramidal neurons and fast-spiking parvalbumin (PV) interneurons is an integral part of higher cognitive functions and is assumed to contribute significantly to brain metabolic responses. Cerebral metabolic rate of oxygen (CMRO2) responses were evoked by optogenetic stimulation of cortical PV interneurons and pyramidal neurons. We found that CMRO2 responses depended on neuronal activation, but not on the power of gamma activity induced by optogenetic stimulation. This implies that evoked gamma activity per se is not energy demanding. Optogenetic stimulation of PV interneurons during somatosensory stimulation reduced excitatory neuronal activity but did not potentiate O2 consumption as previously hypothesized. In conclusion, our data suggest that activity-driven CMRO2 responses depend on neuronal excitation rather than the cerebral rhythmic activity they induce. Excitation of both excitatory and inhibitory neurons requires energy, but inhibition of cortical excitatory neurons by interneurons does not potentiate activity-driven energy consumption.

scholarly journals Postsynaptic and Spiking Activity of Pyramidal Cells, the Principal Neurons in the Rat Hippocampal CA1 Region, Does Not Control the Resultant BOLD Response: A Combined Electrophysiologic and fMRI Approach

2015 ◽  
Vol 35 (4) ◽  
pp. 565-575 ◽  
Author(s):  
Thomas Scherf ◽  
Frank Angenstein
Keyword(s):  
Pyramidal Cells ◽  
Bold Response ◽  
Ca1 Pyramidal Cells ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Postsynaptic Activity ◽  
Hippocampal Ca1 ◽  
Bold Responses ◽  
Stimulation Of ◽  
Spiking Activity

The specific role of postsynaptic activity for the generation of a functional magnetic resonance imaging (fMRI) response was determined by a simultaneous measurement of generated field excitatory postsynaptic potentials (fEPSPs) and blood oxygen level-dependent (BOLD) response in the rat hippocampal CA1 region during electrical stimulation of the contralateral CA3 region. The stimulation electrode was placed either in the left CA3a/b or CA3c, causing the preferentially basal or apical dendrites of the pyramidal cells in the right CA1 to be activated. Consecutive stimulations with low-intensity stimulation trains (i.e., 16 pulses for 8 seconds) resulted in clear postsynaptic responses of CA1 pyramidal cells, but in no significant BOLD responses. In contrast, consecutive high-intensity stimulation trains resulted in stronger postsynaptic responses that came along with minor (during stimulation of the left CA3a/b) or substantial (during stimulation of the left CA3c) spiking activity of the CA1 pyramidal cells, and resulted in the generation of significant BOLD responses in the left and right hippocampus. Correlating the electrophysiologic parameters of CA1 pyramidal cell activity (fEPSP and spiking activity) with the resultant BOLD response revealed no positive correlation. Consequently, postsynaptic activity of pyramidal cells, the most abundant neurons in the CA1, is not directly linked to the measured BOLD response.

scholarly journals NMDA-Dependent Mechanisms Only Affect the BOLD Response in the Rat Dentate Gyrus by Modifying Local Signal Processing

2011 ◽  
Vol 32 (3) ◽  
pp. 570-584 ◽  
Author(s):  
Regina Tiede ◽  
Karla Krautwald ◽  
Anja Fincke ◽  
Frank Angenstein
Keyword(s):  
Signal Processing ◽  
Nmda Receptor ◽  
Dentate Gyrus ◽  
Entorhinal Cortex ◽  
Bold Response ◽  
Electrophysiological Response ◽  
Perforant Pathway ◽  
Bold Responses ◽  
The Right ◽  
Stimulation Of

The role of N-methyl-d-aspartate (NMDA) receptor-mediated mechanisms in the formation of a blood oxygen level-dependent (BOLD) response was studied using electrical stimulation of the right perforant pathway. Stimulation of this fiber bundle triggered BOLD responses in the right hippocampal formation and in the left entorhinal cortex. The perforant pathway projects to and activates the dentate gyrus monosynaptically, activation in the contralateral entorhinal cortex is multisynaptic and requires forwarding and processing of signals. Application of the NMDA receptor antagonist MK801 during stimulation had no effect on BOLD responses in the right dentate gyrus, but reduced the BOLD responses in the left entorhinal cortex. In contrast, application of MK801 before the first stimulation train reduced the BOLD response in both regions. Electrophysiological recordings revealed that the initial stimulation trains changed the local processing of the incoming signals in the dentate gyrus. This altered electrophysiological response was not further changed by a subsequent application of MK801, which is in agreement with an unchanged BOLD response. When MK801 was present during the first stimulation train, a dissimilar electrophysiological response pattern was observed and corresponds to an altered BOLD response, indicating that NMDA-dependent mechanisms indirectly affect the BOLD response, mainly via modifying local signal processing and subsequent propagation.

scholarly journals In vivo optogenetic stimulation of the primate retina activates the visual cortex after long-term transduction

2021 ◽  
Author(s):  
Antoine Chaffiol ◽  
Matthieu Provansal ◽  
Corentin Joffrois ◽  
Kévin Blaize ◽  
Guillaume Labernede ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Information Transfer ◽  
Ganglion Cells ◽  
Ex Vivo ◽  
Spatiotemporal Resolution ◽  
Fluorescent Reporter ◽  
Optogenetic Stimulation ◽  
Stimulation Of

SummaryVarious therapeutic strategies for vision restoration have been developed, including retinal prostheses [1–4], stem cell transplantation [5–8] and optogenetic therapies [9,10,19,11–18]. In optogenetic therapy, the residual retinal neurons surviving the pathological degenerative process are rendered light-sensitive. Using this approach, we targeted the retinal ganglion cells (RGCs) through the in vivo expression of an ectopic light-sensitive ion channel, ChrimsonR [13] coupled to the fluorescent reporter tdTomato. The application of this strategy to blind patients [20] suffering from retinal dystrophies raises important concerns about the long-term functional expression of efficient signal transmission to higher brain centers (i.e. the visual cortex). We have previously shown that the transduced retina displays high spatiotemporal resolution ex vivo, compatible with the perception of highly dynamic visual scenes at light levels suitable for use in humans. Other studies have provided evidence of retinal activation in vivo [17]. Here, we demonstrate, in non-human primates, sustained functional efficacy ~20 months after delivery of an AAV2.7m8-ChrimsonR-tdTomato vector similar to that currently undergoing clinical evaluation. Our results reveal a persistence of expression in the perifovea, mediating information transfer to higher brain centers. Indeed, we recorded visually evoked potentials in the primary visual cortex of anesthetized animals in response to optogenetic retinal activation. We used an intravitreal injection of synaptic blockers to isolate the cortical component resulting from the in vivo optogenetic stimulation of primate RGCs. Our findings demonstrate the long-term functional efficacy of optogenetic retinal information transfer to the brain in vivo.

scholarly journals Incerto-thalamic modulation of fear via GABA and dopamine

2021 ◽  
Author(s):  
Archana Venkataraman ◽  
Sarah C. Hunter ◽  
Maria Dhinojwala ◽  
Diana Ghebrezadik ◽  
JiDong Guo ◽  
...  
Keyword(s):  
Brain Regions ◽  
Zona Incerta ◽  
Dependent Manner ◽  
Post Traumatic Stress ◽  
Functional Roles ◽  
Functional Connections ◽  
Optogenetic Stimulation ◽  
Fear Generalization ◽  
Stimulation Of

AbstractFear generalization and deficits in extinction learning are debilitating dimensions of Post-Traumatic Stress Disorder (PTSD). Most understanding of the neurobiology underlying these dimensions comes from studies of cortical and limbic brain regions. While thalamic and subthalamic regions have been implicated in modulating fear, the potential for incerto-thalamic pathways to suppress fear generalization and rescue deficits in extinction recall remains unexplored. We first used patch-clamp electrophysiology to examine functional connections between the subthalamic zona incerta and thalamic reuniens (RE). Optogenetic stimulation of GABAergic ZI → RE cell terminals in vitro induced inhibitory post-synaptic currents (IPSCs) in the RE. We then combined high-intensity discriminative auditory fear conditioning with cell-type-specific and projection-specific optogenetics in mice to assess functional roles of GABAergic ZI → RE cell projections in modulating fear generalization and extinction recall. In addition, we used a similar approach to test the possibility of fear generalization and extinction recall being modulated by a smaller subset of GABAergic ZI → RE cells, the A13 dopaminergic cell population. Optogenetic stimulation of GABAergic ZI → RE cell terminals attenuated fear generalization and enhanced extinction recall. In contrast, optogenetic stimulation of dopaminergic ZI → RE cell terminals had no effect on fear generalization but enhanced extinction recall in a dopamine receptor D1-dependent manner. Our findings shed new light on the neuroanatomy and neurochemistry of ZI-located cells that contribute to adaptive fear by increasing the precision and extinction of learned associations. In so doing, these data reveal novel neuroanatomical substrates that could be therapeutically targeted for treatment of PTSD.

scholarly journals Involvement of MCH-oxytocin neural relay within the hypothalamus in murine nursing behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoko Kato ◽  
Harumi Katsumata ◽  
Ayumu Inutsuka ◽  
Akihiro Yamanaka ◽  
Tatsushi Onaka ◽  
...  
Keyword(s):  
Mammalian Species ◽  
Virgin Female ◽  
Essential Elements ◽  
Hypothalamic Nucleus ◽  
Male Mice ◽  
Hypothalamic Area ◽  
Functional Roles ◽  
Genetic Ablation ◽  
Optogenetic Stimulation ◽  
Stimulation Of

AbstractMultiple sequential actions, performed during parental behaviors, are essential elements of reproduction in mammalian species. We showed that neurons expressing melanin concentrating hormone (MCH) in the lateral hypothalamic area (LHA) are more active in rodents of both sexes when exhibiting parental nursing behavior. Genetic ablation of the LHA-MCH neurons impaired maternal nursing. The post-birth survival rate was lower in pups born to female mice with congenitally ablated MCH neurons under control of tet-off system, exhibiting reduced crouching behavior. Virgin female and male mice with ablated MCH neurons were less interested in pups and maternal care. Chemogenetic and optogenetic stimulation of LHA-MCH neurons induced parental nursing in virgin female and male mice. LHA-MCH GABAergic neurons project fibres to the paraventricular hypothalamic nucleus (PVN) neurons. Optogenetic stimulation of PVN induces nursing crouching behavior along with increasing plasma oxytocin levels. The hypothalamic MCH neural relays play important functional roles in parental nursing behavior in female and male mice.

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