scholarly journals A neural circuit for gamma-band coherence across the retinotopic map in mouse visual cortex

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Richard Hakim ◽  
Kiarash Shamardani ◽  
Hillel Adesnik
Keyword(s):  
Visual Cortex ◽  
Neural Circuit ◽  
Brain Slices ◽  
Pyramidal Cells ◽  
Gamma Oscillations ◽  
Gamma Band ◽  
Neuron Activity ◽  
Mouse Visual Cortex ◽  
Retinotopic Map

Cortical gamma oscillations have been implicated in a variety of cognitive, behavioral, and circuit-level phenomena. However, the circuit mechanisms of gamma-band generation and synchronization across cortical space remain uncertain. Using optogenetic patterned illumination in acute brain slices of mouse visual cortex, we define a circuit composed of layer 2/3 (L2/3) pyramidal cells and somatostatin (SOM) interneurons that phase-locks ensembles across the retinotopic map. The network oscillations generated here emerge from non-periodic stimuli, and are stimulus size-dependent, coherent across cortical space, narrow band (30 Hz), and depend on SOM neuron but not parvalbumin (PV) neuron activity; similar to visually induced gamma oscillations observed in vivo. Gamma oscillations generated in separate cortical locations exhibited high coherence as far apart as 850 μm, and lateral gamma entrainment depended on SOM neuron activity. These data identify a circuit that is sufficient to mediate long-range gamma-band coherence in the primary visual cortex.

scholarly journals Sensory-driven and spontaneous gamma oscillations engage distinct cortical circuitry

2016 ◽  
Vol 115 (4) ◽  
pp. 1821-1835 ◽  
Author(s):  
Cristin G. Welle ◽  
Diego Contreras
Keyword(s):  
Visual Cortex ◽  
Visual Stimulation ◽  
Oscillation Amplitude ◽  
Gamma Oscillations ◽  
Gamma Oscillation ◽  
Inhibitory Neurons ◽  
Sensory Representation ◽  
Cortical Circuitry ◽  
Mouse Visual Cortex

Gamma oscillations are a robust component of sensory responses but are also part of the background spontaneous activity of the brain. To determine whether the properties of gamma oscillations in cortex are specific to their mechanism of generation, we compared in mouse visual cortex in vivo the laminar geometry and single-neuron rhythmicity of oscillations produced during sensory representation with those occurring spontaneously in the absence of stimulation. In mouse visual cortex under anesthesia (isoflurane and xylazine), visual stimulation triggered oscillations mainly between 20 and 50 Hz, which, because of their similar functional significance to gamma oscillations in higher mammals, we define here as gamma range. Sensory representation in visual cortex specifically increased gamma oscillation amplitude in the supragranular (L2/3) and granular (L4) layers and strongly entrained putative excitatory and inhibitory neurons in infragranular layers, while spontaneous gamma oscillations were distributed evenly through the cortical depth and primarily entrained putative inhibitory neurons in the infragranular (L5/6) cortical layers. The difference in laminar distribution of gamma oscillations during the two different conditions may result from differences in the source of excitatory input to the cortex. In addition, modulation of superficial gamma oscillation amplitude did not result in a corresponding change in deep-layer oscillations, suggesting that superficial and deep layers of cortex may utilize independent but related networks for gamma generation. These results demonstrate that stimulus-driven gamma oscillations engage cortical circuitry in a manner distinct from spontaneous oscillations and suggest multiple networks for the generation of gamma oscillations in cortex.

scholarly journals Evidence that PV+ cells enhance temporal population codes but not stimulus-related timing in auditory cortex

2017 ◽  
Author(s):  
Bryan M. Krause ◽  
Caitlin A. Murphy ◽  
Daniel J. Uhlrich ◽  
Matthew I. Banks
Keyword(s):  
Brain Slices ◽  
Pyramidal Cells ◽  
Gamma Oscillations ◽  
Cortical Activity ◽  
Spike Timing ◽  
Network Activity ◽  
Local Network ◽  
Network Bursts ◽  
Spatio Temporal

AbstractSpatio-temporal cortical activity patterns relative to both peripheral input and local network activity carry information about stimulus identity and context. GABAergic interneurons are reported to regulate spiking at millisecond precision in response to sensory stimulation and during gamma oscillations; their role in regulating spike timing during induced network bursts is unclear. We investigated this issue in murine auditory thalamo-cortical (TC) brain slices, in which TC afferents induced network bursts similar to previous reports in vivo. Spike timing relative to TC afferent stimulation during bursts was poor in pyramidal cells and SOM+ interneurons. It was more precise in PV+ interneurons, consistent with their reported contribution to spiking precision in pyramidal cells. Optogenetic suppression of PV+ cells unexpectedly improved afferent-locked spike timing in pyramidal cells. In contrast, our evidence suggests that PV+ cells do regulate the spatio-temporal spike pattern of pyramidal cells during network bursts, whose organization is suited to ensemble coding of stimulus information. Simulations showed that suppressing PV+ cells reduces the capacity of pyramidal cell networks to produce discriminable spike patterns. By dissociating temporal precision with respect to a stimulus versus internal cortical activity, we identified a novel role for GABAergic cells in regulating information processing in cortical networks.

scholarly journals NMDAR-independent acetylcholine, serotonin, and norepinephrine mediated modulation of synaptic eligibility traces into LTD in mice visual cortex

2020 ◽  
Author(s):  
Shumsuzzaman Khan
Keyword(s):  
Visual Cortex ◽  
Ex Vivo ◽  
Brain Slices ◽  
Low Frequency ◽  
Decay Kinetics ◽  
Low Frequency Stimulation ◽  
Long Term Changes ◽  
Frequency Stimulation ◽  
Mouse Visual Cortex

AbstractIn reward-based learning, synaptic eligibility traces are a well-defined theoretical solution for the conversion of initial co-activation of pre and postsynaptic neurons into long-term changes in synaptic strength by reward-linked neuromodulators. However, the types of neuromodulators involved in such a phenomenon in mouse visual cortex remain unknown. To characterize the Ex vivo condition, we used optogenetic stimulation of channelrhodopsin-(ChR2) expressing Cre/Ai32(ChR2-eYFP); Tph2-Cre/Ai32(ChR2-eYFP); Thi-Cre/Ai32(ChR2-eYFP) homozygous mice, which release acetylcholine, serotonin, and norepinephrine, respectively. With these mice it is possible to measure the transformation of eligibility traces into long-term changes by endogenous neuromodulators. Here we delineated that layer 2/3 neurons in the visual cortex showed no LTD after conditioning with paired-pulse low-frequency stimulation (ppLFS; 2Hz, 15 min). However, if conditioning was paired with acetylcholine, serotonin, or norepinephrine release upon 473 nm optical stimulation in brain slices, LTD occurs in every case. Thus, our data suggests a new pathway to connect the gap between stimulus and reward. Moreover, we found that stimulation by theta-glass or metal stimulators evoked IPSC traces with the same amplitudes but differences in decay kinetics, further questioning the appropriate use of stimulators in brain slices for evoking an event.

scholarly journals Agrp neuron activity is required for alcohol-induced overeating

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Sarah Cains ◽  
Craig Blomeley ◽  
Mihaly Kollo ◽  
Romeo Rácz ◽  
Denis Burdakov
Keyword(s):  
Alcohol Intake ◽  
Cell Activity ◽  
Brain Slices ◽  
Biological Factor ◽  
Calorie Intake ◽  
Neuron Activity ◽  
Biological Factors ◽  
Societal Factors ◽  
Core Elements

Abstract Alcohol intake associates with overeating in humans. This overeating is a clinical concern, but its causes are puzzling, because alcohol (ethanol) is a calorie-dense nutrient, and calorie intake usually suppresses brain appetite signals. The biological factors necessary for ethanol-induced overeating remain unclear, and societal causes have been proposed. Here we show that core elements of the brain’s feeding circuits—the hypothalamic Agrp neurons that are normally activated by starvation and evoke intense hunger—display electrical and biochemical hyperactivity on exposure to dietary doses of ethanol in brain slices. Furthermore, by circuit-specific chemogenetic interference in vivo, we find that the Agrp cell activity is essential for ethanol-induced overeating in the absence of societal factors, in single-housed mice. These data reveal how a widely consumed nutrient can paradoxically sustain brain starvation signals, and identify a biological factor required for appetite evoked by alcohol.

scholarly journals In vivo STED microscopy visualizes PSD95 sub-structures and morphological changes over several hours in the mouse visual cortex

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Waja Wegner ◽  
Alexander C. Mott ◽  
Seth G. N. Grant ◽  
Heinz Steffens ◽  
Katrin I. Willig
Keyword(s):  
Visual Cortex ◽  
Morphological Changes ◽  
Sted Microscopy ◽  
Mouse Visual Cortex

scholarly journals Precise Mapping of Single Neurons by Calibrated 3D Reconstruction of Brain Slices Reveals Topographic Projection in Mouse Visual Cortex

Cell Reports ◽  
2020 ◽  
Vol 31 (8) ◽  
pp. 107682 ◽  
Author(s):  
Jun Ho Song ◽  
Woochul Choi ◽  
You-Hyang Song ◽  
Jae-Hyun Kim ◽  
Daun Jeong ◽  
...  
Keyword(s):  
Visual Cortex ◽  
3D Reconstruction ◽  
Brain Slices ◽  
Single Neurons ◽  
Precise Mapping ◽  
Mouse Visual Cortex
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