Laminar Analysis of Excitatory Local Circuits in Vibrissal Motor and Sensory Cortical Areas

Hooks, Bryan M.; Hires, Samuel Andrew; Zhang, Ying Xin; Huber, Daniel; Petreanu, Leopoldo; Svoboda, Karel; Shepherd, Gordon M.

doi:10.1371/journal.pbio.1000572

Cited by 211 publications

(294 citation statements)

References 57 publications

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“…These results illustrate which excitatory neurons of the S1 cortical column send information through L6 CTNs to the thalamic compartment corresponding to the column. Strong local excitatory inputs to L6 CTNs from their own layer were found in previous studies using laser-scanning photostimulation by glutamate uncaging (Zarrinpar and Callaway, 2006;Llano and Sherman, 2009;Lam and Sherman, 2010;Hooks et al, 2011). Because photostimulation with a resolution of 50 -75 m probably would activate several CTNs simultaneously (Hooks et al, 2011), large EPSPs might be evoked in the recorded neuron through dense nearby connections between CTNs.…”

Section: Discussionmentioning

confidence: 70%

“…In this reciprocal circuit, L6 corticothalamic projection neurons (CTNs) are considered to enhance and tune thalamic responses to peripheral stimuli (Yuan et al, 1986;Yan and Suga, 1996;Przybyszewski et al, 2000;Alitto and Usrey, 2003;Temereanca and Simons, 2004;Thomson, 2010). Local connections between cortical layers are well developed (Briggs and Callaway, 2001;Mercer et al, 2005;Zarrinpar and Callaway, 2006;West et al, 2006;Lefort et al, 2009;Llano and Sherman, 2009;Lam and Sherman, 2010;Hooks et al, 2011), and in addition to external inputs, local translaminar inputs are involved in shaping CTN activity. Therefore, the laminar organization of local excitatory inputs to CTNs may be important for cortical modulation of thalamic activity.…”

Section: Introductionmentioning

confidence: 99%

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Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Tanaka

Tanaka²,

Konno³

et al. 2011

J. Neurosci.

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Corticothalamic projection neurons in the cerebral cortex constitute an important component of the thalamocortical reciprocal circuit, an essential input/output organization for cortical information processing. However, the spatial organization of local excitatory connections to corticothalamic neurons is only partially understood. In the present study, we first developed an adenovirus vector expressing somatodendritic membrane-targeted green fluorescent protein. After injection of the adenovirus vector into the ventrobasal thalamic complex, a band of layer (L) 6 corticothalamic neurons in the rat barrel cortex were retrogradely labeled. In addition to their cell bodies, fine dendritic spines of corticothalamic neurons were well visualized without the labeling of their axon collaterals or thalamocortical axons. In cortical slices containing retrogradely labeled L6 corticothalamic neurons, we intracellularly stained single pyramidal/spiny neurons of L2-6. We examined the spatial distribution of contact sites between the local axon collaterals of each pyramidal neuron and the dendrites of corticothalamic neurons. We found that corticothalamic neurons received strong and focused connections from L4 neurons just above them, and that the most numerous nearby and distant sources of local excitatory connections to corticothalamic neurons were corticothalamic neurons themselves and L6 putative corticocortical neurons, respectively. These results suggest that L4 neurons may serve as an important source of local excitatory inputs in shaping the cortical modulation of thalamic activity.

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Section: Discussionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Tanaka

Tanaka²,

Konno³

et al. 2011

J. Neurosci.

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“…Previous studies have investigated the function of dendrites on L5 pyramidal neurons in vivo but restricted imaging to superficial dendrites of the tuft (12,13). In these studies, imaging was performed in barrel cortex, where L5 begins at 600 μm or more below the pial surface (14). This depth is below the reach of conventional two-photon calcium imaging, and special techniques developed to image this deep have only been used to record somatic calcium activity (19).…”

Section: Discussionmentioning

confidence: 99%

“…We circumvented this issue by focusing on the whisker representation area in wM1. This cortical region lacks a granular layer and so has a relatively superficial location of L5 that begins at 260 μm below the pia (14). Given the high convergence of projections from other brain regions onto wM1 (20)(21)(22), the importance of wM1 in tactile behavior and learning (23)(24)(25), and the capability to perform two-photon imaging in multiple layers, this system is ideally suited for studies of dendritic integration in vivo.…”

Section: Discussionmentioning

confidence: 99%

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Multibranch activity in basal and tuft dendrites during firing of layer 5 cortical neurons in vivo

Hill

Varga

Jia

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Layer 5 pyramidal neurons process information from multiple cortical layers to provide a major output of cortex. Because of technical limitations it has remained unclear how these cells integrate widespread synaptic inputs located in distantly separated basal and tuft dendrites. Here, we obtained in vivo twophoton calcium imaging recordings from the entire dendritic field of layer 5 motor cortex neurons. We demonstrate that during subthreshold activity, basal and tuft dendrites exhibit spatially localized, small-amplitude calcium transients reflecting afferent synaptic inputs. During action potential firing, calcium signals in basal dendrites are linearly related to spike activity, whereas calcium signals in the tuft occur unreliably. However, in both dendritic compartments, spike-associated calcium signals were uniformly distributed throughout all branches. Thus, our data support a model of widespread, multibranch integration with a direct impact by basal dendrites and only a partial contribution on output signaling by the tuft.excitatory synapses | dendritic integration | mouse motor cortex P yramidal neurons feature extensive dendritic arborizations that receive and process widespread synaptic input. Much interest has been placed on the role of individual dendritic branches in determining neuronal output (1). The single branch has been hypothesized to function as a unit of plasticity (2), protein synthesis (3), and synaptic integration (4). Moreover, single dendritic branches have been shown to generate spatially restricted regenerative events, the so-called dendritic spikes, which can process and amplify local input (5). These features raise the question of whether the input-output relation of a cortical neuron is influenced primarily by single dendrites or by multibranch activity.Layer 5 (L5) pyramidal neurons serve as the major output cell type of neocortex. Their morphology is characterized by a set of basal dendrites as well as a set of distal tuft dendrites that extend into layer 1 and are separated from the soma by a long apical trunk (6). These compartments are known to be specialized in terms of the type of synaptic input that they receive (7). Furthermore, in vitro studies of dendritic physiology have revealed several active dendritic signals in these compartments such as back-propagation of action potentials (bAPs) (8, 9), NMDA spikes resulting from clustered synaptic activation (5), and calcium spikes initiated in the apical trunk (10, 11). Despite the presence of these dendritic specializations, little is known about the importance of these features for in vivo function. Previous in vivo studies were limited by the technical challenges of recording from deep basal structures in L5 (12) or of recording multiple individual dendrites simultaneously from the same neuron (13). A complete understanding of dendritic integration in L5 pyramidal neurons requires in vivo data from both the basal and tuft compartments with single dendritic branch resolution.Here we address the question of multibranch activi...

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Electrically Controlled Neurochemical Release from Dual‐Layer Conducting Polymer Films for Precise Modulation of Neural Network Activity in Rat Barrel Cortex

Cui

2017

Adv Funct Materials

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Implantable microelectrode arrays (MEAs) are important tools for investigating functional neural circuits and treating neurological diseases. Precise modulation of neural activity may be achieved by controlled delivery of neurochemicals directly from coatings on MEA electrode sites. In this study, a novel dual-layer conductive polymer/acid functionalized carbon nanotube (fCNT) microelectrode coating is developed to better facilitate the loading and controlled delivery of the neurochemical 6,7-dinitroquinoxaline-2,3-dione (DNQX). The base layer coating is consisted of poly(3,4-ethylenedioxythiophene/fCNT and the top layer is consisted of polypyrrole/fCNT/DNQX. The dual-layer coating is capable of both loading and electrically releasing DNQX and the release dynamic is characterized with fluorescence microscopy and mathematical modeling. In vivo DNQX release is demonstrated in rat somatosensory cortex. Sensory-evoked neural activity is immediately (<1s) and locally (<446 µm) suppressed by electrically triggered DNQX release. Furthermore, a single DNQX-loaded, dual-layer coating is capable of inducing effective neural inhibition for at least 26 times without observable degradation in efficacy. Incorporation of the novel drug releasing coating onto individual MEA electrodes offers many advantages over alternative methods by increasing spatial-temporal precision and improving drug selection flexibility without increasing the device’s size.

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Laminar Analysis of Excitatory Local Circuits in Vibrissal Motor and Sensory Cortical Areas

Abstract: Optical and electrophysiological tools were used to map out the neural circuits within and between cortical layers in three different brain regions, and the results suggest regional specializations for sensory versus motor information processing.

Cited by 211 publications

References 57 publications

Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Multibranch activity in basal and tuft dendrites during firing of layer 5 cortical neurons in vivo

Electrically Controlled Neurochemical Release from Dual‐Layer Conducting Polymer Films for Precise Modulation of Neural Network Activity in Rat Barrel Cortex

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