Positive Feedback in a Brainstem Tactile Sensorimotor Loop

Nguyen, Quoc-Thang; Kleinfeld, David

doi:10.1016/j.neuron.2004.12.042

Cited by 112 publications

(91 citation statements)

References 43 publications

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“…Thus, one can speculate that the direct VMC-to-FN pathway plays a role in the generation of complex whisker movements during tactile exploration. Clearly, the elaborate control of whisker movements, comprising monosynaptic (our study) and oligosynaptic (Miyashita et al, 1994;Hattox et al, 2002) corticomotoneuronal projections, brainstem CPG inputs (Hattox et al, 2003), and brainstem trigeminal sensorimotor loop (Nguyen and Kleinfeld, 2005), is likely to contribute to the remarkable tactile acuity of rat active touch in whisker-based texture, shape, and/or distance discriminations (Guic-Robles et al, 1989;Carvell and Simons, 1990;Harvey et al, 2001;Krupa et al, 2001;Brecht et al, 2004b). …”

Section: Corticomotoneuronal Connectivity In Primates and Rodentsmentioning

confidence: 62%

Monosynaptic Pathway from Rat Vibrissa Motor Cortex to Facial Motor Neurons Revealed by Lentivirus-Based Axonal Tracing

Brecht²,

2005

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The mammalian motor cortex typically innervates motor neurons indirectly via oligosynaptic pathways. However, evolution of skilled digit movements in humans, apes, and some monkey species is associated with the emergence of abundant monosynaptic cortical projections onto spinal motor neurons innervating distal limb muscles. Rats perform skilled movements with their whiskers, and we examined the possibility that the rat vibrissa motor cortex (VMC) projects monosynaptically onto facial motor neurons controlling the whisker movements. First, single injections of lentiviruses to VMC sites identified by intracortical microstimulations were used to label a distinct subpopulation of VMC axons or presynaptic terminals by expression of enhanced green fluorescent protein (GFP) or GFPtagged synaptophysin, respectively. Four weeks after the injections, GFP and synaptophysin-GFP labeling of axons and putative presynaptic terminals was detected in the lateral portion of the facial nucleus (FN), in close proximity to motor neurons identified morphologically and by axonal back-labeling from the whisker follicles. The VMC projections were detected bilaterally, with threefold larger density of labeling in the contralateral FN. Next, multiple VMC injections were used to label a large portion of VMC axons, resulting in overall denser but still laterally restricted FN labeling. Ultrastructural analysis of the GFP-labeled VMC axons confirmed the existence of synaptic contacts onto dendrites and somata of FN motor neurons. These findings provide anatomical demonstration of monosynaptic VMCto-FN pathway in the rat and show that lentivirus-based expression of GFP and GFP-tagged presynaptic proteins can be used as a high-resolution neuroanatomical tracing method.

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Section: Corticomotoneuronal Connectivity In Primates and Rodentsmentioning

confidence: 62%

Monosynaptic Pathway from Rat Vibrissa Motor Cortex to Facial Motor Neurons Revealed by Lentivirus-Based Axonal Tracing

Brecht²,

2005

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“…3b-e) [34] may predispose facial nucleus motor neurons to rhythmic discharges. Facial nucleus neurons receive direct sensory input from trigeminal brainstem neurons [35], as well as widespread inputs from other motor centers, some of which will be discussed below [36].…”

Section: Subcortical Control Of Whisker Movementsmentioning

confidence: 99%

Cellular mechanisms of motor control in the vibrissal system

Brecht

Grinevich

Jin

et al. 2006

Pflugers Arch - Eur J Physiol

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In this article we discuss the experimental advantages that the vibrissal motor system offers for analysis of motor control and the specializations of this system related to the unique characteristics of whisker movements. Whisker movements are often rhythmic, fast, and bilateral. Movements of individual whiskers have simple characteristics, whereas, movements of the entire vibrissae array are complex and sophisticated. In the last few years, powerful methods for high precision tracking of whisker movements have become available. The whisker musculature is arranged to permit forward movements of individual whiskers and consists-depending on the species -mainly or exclusively of fast contracting, fast fatigable muscle fibers. Whisker motor neurons are located in the lateral facial nucleus and their cellular properties might contribute to the rhythmicity of whisking. Numerous structures provide input to the lateral facial nucleus, the most mysterious and important one being the putative central pattern generator (CPG). Although recent studies identified candidate structures for the CPG, the precise identity and the functional organization of this structure remains uncertain. The vibrissa motor cortex (VMC) is the largest motor representation in the rodent brain, and recent work has clarified its localization, subdivisions, cytoarchitectonics, and connectivity. Single-cell stimulation experiments in VMC allow determining the cellular basis of cortical motor control with unprecedented precision. The functional significance of whisker movements remains to be determined.

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“…The rodent vibrissial system has been an extremely valuable model for studies attempting to elucidate mechanisms of learning, processing sensory information, and understanding facial sensorimotor reflexes and pathways (Bermejo et al 1996,Nguyen et al 2005,Crish et al 2003,Ahissar et al 2003,Kleinfeld et al 1999. The rodent eye blink model has also been employed to elucidate the relationships between the 5 th and 7 th cranial nerves (Gong et al 2003,Zerari-Mailly et al 2003.…”

Section: Introductionmentioning

confidence: 99%

A novel method of head fixation for the study of rodent facial function

Hadlock

Kowaleski

Mackinnon

et al. 2007

Experimental Neurology

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The rodent vibrissial system offers an excellent model for the study of both sensory and motor function. It has been widely employed to gather data pertaining to sensory and motor function involving the 5 th and 7 th cranial nerves and the central nervous system. Existing methods of head fixation for precise measurements of ocular and vibrissial function involve exposing the cranium and applying dental cement from which two or more threaded rods emerge. This common approach is suboptimal, requiring a relatively complicated implantation procedure, and results in a large, chronic interface between the scalp and environmentally-exposed implant material attached to the skull. Here we describe a head fixation device that is inexpensive, easy to build, less prone to infection, preserves access to the cranial midline, and permits repeated measurements over many months.

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Positive Feedback in a Brainstem Tactile Sensorimotor Loop

Cited by 112 publications

References 43 publications

Monosynaptic Pathway from Rat Vibrissa Motor Cortex to Facial Motor Neurons Revealed by Lentivirus-Based Axonal Tracing

Monosynaptic Pathway from Rat Vibrissa Motor Cortex to Facial Motor Neurons Revealed by Lentivirus-Based Axonal Tracing

Cellular mechanisms of motor control in the vibrissal system

A novel method of head fixation for the study of rodent facial function

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