Reverse-engineering placebo analgesia.

Placebo analgesia is a widely observed clinical phenomenon. Establishing a robust mouse model of placebo analgesia is needed for careful dissection of the underpinning circuit mechanisms. However, previous studies failed to observe consistent placebo effects in rodent models of chronic pain.

Reverse engineering placebo analgesia.

Placebo analgesia is a widely observed clinical phenomenon. Establishing a robust mouse model of placebo analgesia is needed for careful dissection of the underpinning circuit mechanisms. However, previous studies failed to observe consistent placebo effects in rodent models of chronic pain.

Somatosensory cortical signature of facial nociception and vibrotactile touch-induced analgesia.

Pain relief by vibrotactile touch is a common human experience. Previous neurophysiological investigations of its underlying mechanism in animals focused on spinal circuits, while human studies suggested the involvement of supraspinal pathways. Here, we examine the role of primary somatosensory cortex (S1) in touch-induced mechanical and heat analgesia.

Theory of hierarchically organized neuronal oscillator dynamics that mediate rodent rhythmic whisking.

Rodents explore their environment through coordinated orofacial motor actions, including whisking. Whisking can free-run via an oscillator of inhibitory neurons in the medulla and can be paced by breathing. Yet, the mechanics of the whisking oscillator and its interaction with breathing remain to be understood.

The whisking oscillator circuit.

Central oscillators are primordial neural circuits that generate and control rhythmic movements. Mechanistic understanding of these circuits requires genetic identification of the oscillator neurons and their synaptic connections to enable targeted electrophysiological recording and causal manipulation during behaviours. However, such targeting remains a challenge with mammalian systems.

Ascending vestibular pathways to parietal areas MIP and LIPv and efference copy inputs from the medial reticular formation: Functional frameworks for body representations updating and online movement guidance.

The posterior parietal cortex (PPC) serves as a sensorimotor interface by integrating multisensory signals with motor related information for generating and updating body representations and movement plans. Using retrograde transneuronal transfer of rabies virus combined with a conventional tracer, we identified direct and polysynaptic pathways to two PPC areas, the rostral medial intraparietal area (MIP) and the ventral part of the lateral intraparietal area (LIPv) in macaque monkeys. We found that rostral MIP and LIPv receive ascending vestibular pathways, and putative efference copy inputs disynaptically from the medullary medial reticular formation (MRF) where reticulospinal pathways to neck and arm motoneurons originate.

A Common Neuroendocrine Substrate for Diverse General Anesthetics and Sleep.

How general anesthesia (GA) induces loss of consciousness remains unclear, and whether diverse anesthetic drugs and sleep share a common neural pathway is unknown. Previous studies have revealed that many GA drugs inhibit neural activity through targeting GABA receptors. Here, using Fos staining, ex vivo brain slice recording, and in vivo multi-channel electrophysiology, we discovered a core ensemble of hypothalamic neurons in and near the supraoptic nucleus, consisting primarily of neuroendocrine cells, which are persistently and commonly activated by multiple classes of GA drugs.

Vibrissa sensory neurons: Linking distinct morphology to specific physiology and function.

Rodents use an array of long tactile facial hairs, the vibrissae, to locate and discriminate objects. Each vibrissa is densely innervated by multiple different types of trigeminal (TG) sensory neurons. Based on the sensory ending morphology, there are at least six types of vibrissa innervating neurons; whereas based on electrophysiological recordings, vibrissa neurons are generally classified as rapidly adapting (RA) and slowly adapting (SA), and show different responses to whisking movement and/or touch.

The control of eye movements by the cerebellar nuclei: polysynaptic projections from the fastigial, interpositus posterior and dentate nuclei to lateral rectus motoneurons in primates.

Premotor circuits driving extraocular motoneurons and downstream motor outputs of cerebellar nuclei are well known. However, there is, as yet, no unequivocal account of cerebellar output pathways controlling eye movements in primates. Using retrograde transneuronal transfer of rabies virus from the lateral rectus (LR) eye muscle, we studied polysynaptic pathways to LR motoneurons in primates.

Contribution of Cerebellar Loops to Action Timing.

Recent studies of sensorimotor processing have benefited from decision-making paradigms that emphasize the selection of appropriate movements. Selecting when to make those responses, or action timing, is important as well. Although the cerebellum is commonly viewed as a controller of movement dynamics, its role in action timing is also firmly supported.

Simultaneous transcranial magnetic stimulation and single-neuron recording in alert non-human primates.

Transcranial magnetic stimulation (TMS) is a widely used, noninvasive method for stimulating nervous tissue, yet its mechanisms of effect are poorly understood. Here we report new methods for studying the influence of TMS on single neurons in the brain of alert non-human primates. We designed a TMS coil that focuses its effect near the tip of a recording electrode and recording electronics that enable direct acquisition of neuronal signals at the site of peak stimulus strength minimally perturbed by stimulation artifact in awake monkeys (Macaca mulatta).

Cognitive control of movement via the cerebellar-recipient thalamus.

The cognitive control of behavior was long considered to be centralized in cerebral cortex. More recently, subcortical structures such as cerebellum and basal ganglia have been implicated in cognitive functions as well. The fact that subcortico-cortical circuits for the control of movement involve the thalamus prompts the notion that activity in movement-related thalamus may also reflect elements of cognitive behavior.

Proprioceptive pathways to posterior parietal areas MIP and LIPv from the dorsal column nuclei and the postcentral somatosensory cortex.

The posterior parietal cortex (PPC) serves as an interface between sensory and motor cortices by integrating multisensory signals with motor-related information. Sensorimotor transformation of somatosensory signals is crucial for the generation and updating of body representations and movement plans. Using retrograde transneuronal transfer of rabies virus in combination with a conventional tracer, we identified direct and polysynaptic somatosensory pathways to two posterior parietal areas, the ventral lateral intraparietal area (LIPv) and the rostral part of the medial intraparietal area (MIP) in macaque monkeys.

Posterior parietal cortex areas MIP and LIPv receive eye position and velocity inputs via ascending preposito-thalamo-cortical pathways.

Neuronal activity encoding eye position and gaze signals participates in updating the spatial representations found in the posterior parietal cortex and is necessary for spatial accuracy in goal-directed movements. Using retrograde transneuronal transfer of rabies virus in combination with a conventional tracer, we studied direct and polysynaptic inputs to the ventral lateral intraparietal area (LIPv) and medial intraparietal area (MIP) in non-human primates, to identify possible sources of eye position and gaze signals. We found that these areas receive disynaptic inputs from the brainstem horizontal eye position integrator network (nucleus prepositus hypoglossi, PH) via the central lateral and ventral lateral thalamic nuclei.

Cerebellar inputs to intraparietal cortex areas LIP and MIP: functional frameworks for adaptive control of eye movements, reaching, and arm/eye/head movement coordination.

Using retrograde transneuronal transfer of rabies virus in combination with a conventional tracer (cholera toxin B), we studied simultaneously direct (thalamocortical) and polysynaptic inputs to the ventral lateral intraparietal area (LIPv) and the medial intraparietal area (MIP) in nonhuman primates. We found that these areas receive major disynaptic inputs from specific portions of the cerebellar nuclei, the ventral dentate (D), and ventrolateral interpositus posterior (IP). Area LIPv receives inputs from oculomotor domains of the caudal D and IP.