scholarly journals Transient coupling between subplate and subgranular layers to L1 neurons before and during the critical period

2020 ◽  
Author(s):  
Xiangying Meng ◽  
Yanqing Xu ◽  
Joseph P. Y. Kao ◽  
Patrick O. Kanold
Keyword(s):  
Similar Pattern ◽  
Critical Period ◽  
Laser Scanning ◽  
Primary Auditory Cortex ◽  
Excitatory Input ◽  
Cortical Layer ◽  
Cortical Circuits ◽  
Inhibitory Circuits ◽  
Sensory Activity ◽  
Laser Scanning Photostimulation

AbstractCortical layer 1 (L1) contains a diverse population of interneurons which can modulate processing in superficial cortical layers but the intracortical sources of synaptic input to these neurons and how these inputs change over development is unknown. We here investigated the changing intracortical connectivity to L1 in primary auditory cortex (A1) in slices of mouse A1 across development using laser-scanning photostimulation. Before P10 L1 cells receive most excitatory input from within L1, L2/3, L4 and L5/6 as well as the subplate. Excitatory inputs from all layers increase and peak during P10-P16, the peak of the critical period. Inhibitory inputs followed a similar pattern. Functional circuit diversity in L1 emerges after P16. In adult, L1 neurons receive ascending inputs from superficial L2/3 and subgranular L5/6, but only few inputs from L4. A subtype of L1 neurons, NDNF+ neurons, follow a similar pattern, suggesting that transient hyperconnectivity is a universal feature of developing cortical circuits. Our results demonstrate that deep excitatory and superficial inhibitory circuits are tightly linked in early development and might provide a functional scaffold for the layers in between. These results suggest that early thalamic driven spontaneous and sensory activity in subplate can be relayed to L1 from the earliest ages on, that the critical period is characterized by high transient columnar hyperconnectivity, and that in particular circuits originating in L5/6 and subplate might play a key role.

scholarly journals Transient Subgranular Hyperconnectivity to L2/3 and Enhanced Pairwise Correlations During the Critical Period in the Mouse Auditory Cortex

2019 ◽  
Vol 30 (3) ◽  
pp. 1914-1930 ◽  
Author(s):  
Xiangying Meng ◽  
Krystyna Solarana ◽  
Zac Bowen ◽  
Ji Liu ◽  
Daniel A Nagode ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Critical Period ◽  
Laser Scanning ◽  
Primary Auditory Cortex ◽  
Excitatory Input ◽  
Two Photon ◽  
Layer 4 ◽  
Neuronal Connections ◽  
Laser Scanning Photostimulation

Abstract During the critical period, neuronal connections are shaped by sensory experience. While the basis for this temporarily heightened plasticity remains unclear, shared connections introducing activity correlations likely play a key role. Thus, we investigated the changing intracortical connectivity in primary auditory cortex (A1) over development. In adult, layer 2/3 (L2/3) neurons receive ascending inputs from layer 4 (L4) and also receive few inputs from subgranular layer 5/6 (L5/6). We measured the spatial pattern of intracortical excitatory and inhibitory connections to L2/3 neurons in slices of mouse A1 across development using laser-scanning photostimulation. Before P11, L2/3 cells receive most excitatory input from within L2/3. Excitatory inputs from L2/3 and L4 increase after P5 and peak during P9–16. L5/6 inputs increase after P5 and provide most input during P12–16, the peak of the critical period. Inhibitory inputs followed a similar pattern. Functional circuit diversity in L2/3 emerges after P16. In vivo two-photon imaging shows low pairwise signal correlations in neighboring neurons before P11, which peak at P15–16 and decline after. Our results suggest that the critical period is characterized by high pairwise activity correlations and that transient hyperconnectivity of specific circuits, in particular those originating in L5/6, might play a key role.

scholarly journals Aberrant development of excitatory circuits to inhibitory neurons in the primary visual cortex after neonatal binocular enucleation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rongkang Deng ◽  
Joseph P. Y. Kao ◽  
Patrick O. Kanold
Keyword(s):  
Visual Cortex ◽  
Nmda Receptors ◽  
Laser Scanning ◽  
Inhibitory Neurons ◽  
Gabaergic Interneurons ◽  
Cortical Circuits ◽  
Retinal Input ◽  
Layer 4 ◽  
Ampa And Nmda Receptors ◽  
Laser Scanning Photostimulation

AbstractThe development of GABAergic interneurons is important for the functional maturation of cortical circuits. After migrating into the cortex, GABAergic interneurons start to receive glutamatergic connections from cortical excitatory neurons and thus gradually become integrated into cortical circuits. These glutamatergic connections are mediated by glutamate receptors including AMPA and NMDA receptors and the ratio of AMPA to NMDA receptors decreases during development. Since previous studies have shown that retinal input can regulate the early development of connections along the visual pathway, we investigated if the maturation of glutamatergic inputs to GABAergic interneurons in the visual cortex requires retinal input. We mapped the spatial pattern of glutamatergic connections to layer 4 (L4) GABAergic interneurons in mouse visual cortex at around postnatal day (P) 16 by laser-scanning photostimulation and investigated the effect of binocular enucleations at P1/P2 on these patterns. Gad2-positive interneurons in enucleated animals showed an increased fraction of AMPAR-mediated input from L2/3 and a decreased fraction of input from L5/6. Parvalbumin-expressing (PV) interneurons showed similar changes in relative connectivity. NMDAR-only input was largely unchanged by enucleation. Our results show that retinal input sculpts the integration of interneurons into V1 circuits and suggest that the development of AMPAR- and NMDAR-only connections might be regulated differently.

scholarly journals Neonatal Hypoxia–Ischemia Causes Functional Circuit Changes in Subplate Neurons

2018 ◽  
Vol 29 (2) ◽  
pp. 765-776 ◽  
Author(s):  
Aminah Sheikh ◽  
Xiangying Meng ◽  
Ji Liu ◽  
Alexandra Mikhailova ◽  
Joseph P Y Kao ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Laser Scanning ◽  
Cell Loss ◽  
Abnormal Development ◽  
Cortical Function ◽  
Neonatal Hypoxia ◽  
Inhibitory Circuits ◽  
Subplate Neurons ◽  
Hypoxia Ischemia ◽  
Laser Scanning Photostimulation

Abstract Neonatal hypoxia–ischemia (HI) in the preterm human results in damage to subcortical developing white matter and cognitive impairments. Subplate neurons (SPNs) are among the first-born cortical neurons and are necessary for normal cerebral development. While moderate or severe HI at P1 in rats leads to SPN loss, it is unclear if HI, esp. forms not associated with overt cell loss lead to altered SPN circuits. Thus, we used two HI models with different severities in P1 rats. Cauterization of the common carotid artery (CCA) causes a largely transient and thus milder ischemia (HI-Caut) while CCA ligation causes more severe ischemia (HI-Lig). While HI-Lig caused subplate damage, HI-Caut did not cause overt histological damage on the light microscopic level. We used laser-scanning photostimulation (LSPS) in acute thalamocortical slices of auditory cortex during P5–10 to study the functional connectivity of SPNs. Both HI categories resulted in hyperconnectivity of excitatory and inhibitory circuits to SPNs. Thus, alterations on the circuit level are present in the absence of cell loss. Our results show that SPN circuits are uniquely susceptible to HI. Given the key developmental role of SPNs, our results suggest that altered SPN circuits might underlie the abnormal development of cortical function after HI.

scholarly journals Subpopulation-specific patterns of intrinsic connectivity in mouse superficial dorsal horn as revealed by laser scanning photostimulation

2013 ◽  
Vol 591 (7) ◽  
pp. 1935-1949 ◽  
Author(s):  
Masafumi Kosugi ◽  
Go Kato ◽  
Stanislav Lukashov ◽  
Gautam Pendse ◽  
Zita Puskar ◽  
...  
Keyword(s):  
Dorsal Horn ◽  
Laser Scanning ◽  
Superficial Dorsal Horn ◽  
Intrinsic Connectivity ◽  
Laser Scanning Photostimulation

scholarly journals Circuit contributions to sensory-driven glutamatergic drive of olfactory bulb mitral and tufted cells during odorant inhalation

2021 ◽  
Author(s):  
Andrew K. Moran ◽  
Thomas P. Eiting ◽  
Matt Wachowiak
Keyword(s):  
Olfactory Bulb ◽  
Gabab Receptor ◽  
Glutamate Release ◽  
Excitatory Input ◽  
Slight Reduction ◽  
Receptor Antagonists ◽  
Glutamate Signaling ◽  
Inhibitory Circuits ◽  
Primary Determinant ◽  
Excitatory Drive

In the mammalian olfactory bulb (OB), mitral/tufted (MT) cells respond to odorant inhalation with diverse temporal patterns that are thought to encode odor information. Much of this diversity is already apparent at the level of glutamatergic input to MT cells, which receive direct, monosynaptic excitatory input from olfactory sensory neurons (OSNs) as well as multisynaptic excitatory drive via glutamatergic interneurons. Both pathways are also subject to modulation by inhibitory circuits in the glomerular layer of the OB. To understand the role of direct OSN input versus postsynaptic OB circuit mechanisms in shaping diverse dynamics of glutamatergic drive to MT cells, we imaged glutamate signaling onto MT cell dendrites in anesthetized mice while blocking multisynaptic excitatory drive with ionotropic glutamate receptor antagonists and blocking presynaptic modulation of glutamate release from OSNs with GABAB receptor antagonists. GABAB receptor blockade increased the magnitude of inhalation-linked glutamate transients onto MT cell apical dendrites without altering their inhalation-linked dynamics, confirming that presynaptic inhibition impacts the gain of OSN inputs to the OB. Surprisingly, blockade of multisynaptic excitation only modestly impacted glutamatergic input to MT cells, causing a slight reduction in the amplitude of inhalation-linked glutamate transients in response to low odorant concentrations and no change in the dynamics of each transient. Postsynaptic blockade also modestly impacted glutamate dynamics over a slower timescale, mainly by reducing adaptation of the glutamate response across multiple inhalations of odorant. These results suggest that direct glutamatergic input from OSNs provides the bulk of excitatory drive to MT cells, and that diversity in the dynamics of this input may be a primary determinant of the temporal diversity in MT cell responses that underlies odor representations at this stage.

Effects of ear plugging on single-unit azimuth sensitivity in cat primary auditory cortex. I. Evidence for monaural directional cues

1993 ◽  
Vol 70 (2) ◽  
pp. 492-511 ◽  
Author(s):  
F. K. Samson ◽  
J. C. Clarey ◽  
P. Barone ◽  
T. J. Imig
Keyword(s):  
Auditory Cortex ◽  
Single Unit ◽  
Free Field ◽  
Primary Auditory Cortex ◽  
Total Sample ◽  
Excitatory Input ◽  
The Other ◽  
Inhibitory Input ◽  
Binaural Stimulation ◽  
Monaural Stimulation

1. Single-unit recordings were carried out in primary auditory cortex (AI) of barbiturate-anesthetized cats. Neurons, sensitive to sound direction in the horizontal plane (azimuth), were identified by their responses to noise bursts, presented in the free field, that varied in azimuth and sound pressure level (SPL). SPLs typically varied between 0 and 80 dB and were presented at each azimuth that was tested. Each azimuth-sensitive neuron responded well to some SPLs at certain azimuths and did not respond well to any SPL at other azimuths. This report describes AI neurons that were sensitive to the azimuth of monaurally presented noise bursts. 2. Unilateral ear plugging was used to test each azimuth-sensitive neuron's response to monaural stimulation. Ear plugs, produced by injecting a plastic ear mold compound into the concha and ear canal, attenuated sound reaching the tympanic membrane by 25-70 dB. Binaural interactions were inferred by comparing responses obtained under binaural (no plug) and monaural (ear plug) conditions. 3. Of the total sample of 131 azimuth-sensitive cells whose responses to ear plugging were studied, 27 were sensitive to the azimuth of monaurally presented noise bursts. We refer to these as monaural directional (MD) cells, and this report describes their properties. The remainder of the sample consisted of cells that either required binaural stimulation for azimuth sensitivity (63/131), because they were insensitive to azimuth under unilateral ear plug conditions or responded too unreliably to permit detailed conclusions regarding the effect of ear plugging (41/131). 4. Most (25/27) MD cells received either monaural input (MD-E0) or binaural excitatory/inhibitory input (MD-EI), as inferred from ear plugging. Two MD cells showed other characteristics. The contralateral ear was excitatory for 25/27 MD cells. 5. MD-E0 cells (22%, 6/27) were monaural. They were unaffected by unilateral ear plugging, showing that they received excitatory input from one ear, and that stimulation of the other ear was without apparent effect. On the other hand, some monaural cells in AI were insensitive to the azimuth of noise bursts, showing that sensitivity to monaural directional cues is not a property of all monaural cells in AI. 6. MD-EI cells (70%, 19/27) exhibited an increase in responsiveness on the side of the plugged ear, showing that they received excitatory drive from one ear and inhibitory drive from the other. MD-EI cells remained azimuth sensitive with the inhibitory ear plugged, showing that they were sensitive to monaural directional cues at the excitatory ear.(ABSTRACT TRUNCATED AT 400 WORDS)

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