@article{pmid40438628,

title = {Polysemia as a concept to understand the encoding of sensory information},

author = {Christian Ethier and Zohreh Vaziri and Martin Deschênes},

doi = {10.3389/fnins.2025.1588437},

issn = {1662-4548},

year  = {2025},

date = {2025-01-01},

journal = {Front Neurosci},

volume = {19},

pages = {1588437},

abstract = {In this article, we explore the concept of polysemia in sensory information processing within the brain. We suggest that, just as words can have different meanings based on context, sensory inputs are interpreted differently depending on the animal's current state and behavior. Focusing on the trigeminal sensory nuclei in rats, we highlight the role of inhibitory circuits in gating sensory information and propose that sensory signals are polysemic, with their meaning influenced by emotional, hormonal, and motivational factors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37757586,

title = {Low- and high-level coordination of orofacial motor actions},

author = {David Kleinfeld and Martin Deschênes and Michael N Economo and Michaël Elbaz and David Golomb and Song-Mao Liao and Daniel H O'Connor and Fan Wang},

doi = {10.1016/j.conb.2023.102784},

issn = {1873-6882},

year  = {2023},

date = {2023-12-01},

journal = {Curr Opin Neurobiol},

volume = {83},

pages = {102784},

abstract = {Orofacial motor actions are movements that, in rodents, involve whisking of the vibrissa, deflection of the nose, licking and lapping with the tongue, and consumption through chewing. These actions, along with bobbing and turning of the head, coordinate to subserve exploration while not conflicting with life-supporting actions such as breathing and swallowing. Orofacial and head movements are comprised of two additive components: a rhythm that can be entrained by the breathing oscillator and a broadband component that directs the actuator to the region of interest. We focus on coordinating the rhythmic component of actions into a behavior. We hypothesize that the precise timing of each constituent action is continually adjusted through the merging of low-level oscillator input with sensory-derived, high-level rhythmic feedback. Supporting evidence is discussed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37703878,

title = {A brainstem circuit for the expression of defensive facial reactions in rat},

author = {Amalia Callado Pérez and Maxime Demers and Arash Fassihi and Jeffrey D Moore and David Kleinfeld and Martin Deschênes},

doi = {10.1016/j.cub.2023.08.041},

issn = {1879-0445},

year  = {2023},

date = {2023-09-01},

journal = {Curr Biol},

volume = {33},

number = {18},

pages = {4030--4035.e3},

abstract = {The brainstem houses neuronal circuits that control homeostasis of vital functions. These include the depth and rate of breathing and, critically, apnea, a transient cessation of breathing that prevents noxious vapors from entering further into the respiratory tract. Current thinking is that this reflex is mediated by two sensory pathways. One known pathway involves vagal and glossopharyngeal afferents that project to the nucleus of the solitary tract. Yet, apnea induced by electrical stimulation of the nasal epithelium or delivery of ammonia vapors to the nose persists after brainstem transection at the pontomedullary junction, indicating that the circuitry that mediates this reflex is intrinsic to the medulla. A second potential pathway, consistent with this observation, involves trigeminal afferents from the nasal cavity that project to the muralis subnucleus of the spinal trigeminal complex. Notably, the apneic reflex is not dependent on olfaction as it can be initiated even after disruption of olfactory pathways. We investigated how subnucleus muralis cells mediate apnea in rat. By means of electrophysiological recordings and lesions in anesthetized rats, we identified a pathway from chemosensors in the nostrils through the muralis subnucleus and onto both the preBötzinger and facial motor nuclei. We then monitored breathing and orofacial reactions upon ammonia delivery near the nostril of alert, head-restrained rats. The apneic reaction was associated with a grimace, characterized by vibrissa protraction, wrinkling of the nose, and squinting of the eyes. Our results show that a brainstem circuit can control facial expressions for nocifensive and potentially pain-inducing stimuli.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37400255,

title = {Interchangeable Role of Motor Cortex and Reafference for the Stable Execution of an Orofacial Action},

author = {Michaël A Elbaz and Maxime Demers and David Kleinfeld and Christian Ethier and Martin Deschênes},

doi = {10.1523/JNEUROSCI.2089-22.2023},

issn = {1529-2401},

year  = {2023},

date = {2023-07-01},

journal = {J Neurosci},

volume = {43},

number = {30},

pages = {5521--5536},

abstract = {Animals interact with their environment through mechanically active, mobile sensors. The efficient use of these sensory organs implies the ability to track their position; otherwise, perceptual stability or prehension would be profoundly impeded. The nervous system may keep track of the position of a sensorimotor organ via two complementary feedback mechanisms-peripheral reafference (external, sensory feedback) and efference copy (internal feedback). Yet, the potential contributions of these mechanisms remain largely unexplored. By training male rats to place one of their vibrissae within a predetermined angular range without contact, a task that depends on knowledge of vibrissa position relative to their face, we found that peripheral reafference is not required. The presence of motor cortex is not required either, except in the absence of peripheral reafference to maintain motor stability. Finally, the red nucleus, which receives descending inputs from motor cortex and cerebellum and projects to facial motoneurons, is critically involved in the execution of the vibrissa positioning task. All told, our results point toward the existence of an internal model that requires either peripheral reafference or motor cortex to optimally drive voluntary motion. How does an animal know where a mechanically active, mobile sensor lies relative to its body? We address this basic question in sensorimotor integration using the motion of the vibrissae in rats. We show that rats can learn to reliably position their vibrissae in the absence of sensory feedback or in the absence of motor cortex. Yet, when both sensory feedback and motor cortex are absent, motor precision is degraded. This suggests the existence of an internal model able to operate in closed- and open-loop modes, requiring either motor cortex or sensory feedback to maintain motor stability.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35142608,

title = {A vibrissa pathway that activates the limbic system},

author = {Michaël Elbaz and Amalia Callado Perez and Maxime Demers and Shengli Zhao and Conrad Foo and David Kleinfeld and Martin Deschenes},

doi = {10.7554/eLife.72096},

issn = {2050-084X},

year  = {2022},

date = {2022-02-01},

journal = {Elife},

volume = {11},

abstract = {Vibrissa sensory inputs play a central role in driving rodent behavior. These inputs transit through the sensory trigeminal nuclei, which give rise to the ascending lemniscal and paralemniscal pathways. While lemniscal projections are somatotopically mapped from brainstem to cortex, those of the paralemniscal pathway are more widely distributed. Yet the extent and topography of paralemniscal projections are unknown, along with the potential role of these projections in controlling behavior. Here, we used viral tracers to map paralemniscal projections. We find that this pathway broadcasts vibrissa-based sensory signals to brainstem regions that are involved in the regulation of autonomic functions and to forebrain regions that are involved in the expression of emotional reactions. We further provide evidence that GABAergic cells of the Kölliker-Fuse nucleus gate trigeminal sensory input in the paralemniscal pathway via a mechanism of presynaptic or extrasynaptic inhibition.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid30461370,

title = {Functional brain stem circuits for control of nose motion},

author = {Anastasia Kurnikova and Martin Deschênes and David Kleinfeld},

doi = {10.1152/jn.00608.2018},

issn = {1522-1598},

year  = {2019},

date = {2019-01-01},

journal = {J Neurophysiol},

volume = {121},

number = {1},

pages = {205--217},

abstract = {Rodents shift their nose from side to side when they actively explore and lateralize odors in the space. This motor action is driven by a pair of muscles, the deflector nasi. We studied the premotor control of this motion. We used replication-competent rabies virus to transsynaptically label inputs to the deflector nasi muscle and find putative premotor labeling throughout the parvocellular, intermediate, and gigantocellular reticular formations, as well as the trigeminal nuclei, pontine reticular formation, midbrain reticular formation, red nucleus, and superior colliculus. Two areas with extensive labeling were analyzed for their impact on nose movement. One area is in the reticular formation caudal to the facial motor nucleus and is denoted the nose retrofacial area. The second is in the caudal part of the intermediate reticular region near the oscillator for whisking (the nose IRt). Functionally, we find that optogenetic activation of glutamatergic cells in both areas drives deflection of the nose. Ablation of cells in the nose retrofacial area, but not the nose IRt, impairs movement of the nose in response to the presentation of odorants but otherwise leaves movement unaffected. These data suggest that the nose retrofacial area is a conduit for a sensory-driven orofacial motor action. Furthermore, we find labeling of neurons that are immediately upstream of premotor neurons in the preBötzinger complex that presumably synchronizes a small, rhythmic component of nose motion to breathing. NEW & NOTEWORTHY We identify two previously undescribed premotor areas in the medulla that control deflection of the nose. This includes a pathway for directed motion of the nose in response to an odorant.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28843993,

title = {Circuits in the rodent brainstem that control whisking in concert with other orofacial motor actions},

author = {Lauren E McElvain and Beth Friedman and Harvey J Karten and Karel Svoboda and Fan Wang and Martin Deschênes and David Kleinfeld},

doi = {10.1016/j.neuroscience.2017.08.034},

issn = {1873-7544},

year  = {2018},

date = {2018-01-01},

journal = {Neuroscience},

volume = {368},

pages = {152--170},

abstract = {The world view of rodents is largely determined by sensation on two length scales. One is within the animal's peri-personal space; sensorimotor control on this scale involves active movements of the nose, tongue, head, and vibrissa, along with sniffing to determine olfactory clues. The second scale involves the detection of more distant space through vision and audition; these detection processes also impact repositioning of the head, eyes, and ears. Here we focus on orofacial motor actions, primarily vibrissa-based touch but including nose twitching, head bobbing, and licking, that control sensation at short, peri-personal distances. The orofacial nuclei for control of the motor plants, as well as primary and secondary sensory nuclei associated with these motor actions, lie within the hindbrain. The current data support three themes: First, the position of the sensors is determined by the summation of two drive signals, i.e., a fast rhythmic component and an evolving orienting component. Second, the rhythmic component is coordinated across all orofacial motor actions and is phase-locked to sniffing as the animal explores. Reverse engineering reveals that the preBötzinger inspiratory complex provides the reset to the relevant premotor oscillators. Third, direct feedback from somatosensory trigeminal nuclei can rapidly alter motion of the sensors. This feedback is disynaptic and can be tuned by high-level inputs. A holistic model for the coordination of orofacial motor actions into behaviors will encompass feedback pathways through the midbrain and forebrain, as well as hindbrain areas.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28735746,

title = {Parallel Inhibitory and Excitatory Trigemino-Facial Feedback Circuitry for Reflexive Vibrissa Movement},

author = {Marie-Andrée Bellavance and Jun Takatoh and Jinghao Lu and Maxime Demers and David Kleinfeld and Fan Wang and Martin Deschênes},

doi = {10.1016/j.neuron.2017.06.045},

issn = {1097-4199},

year  = {2017},

date = {2017-08-01},

journal = {Neuron},

volume = {95},

number = {3},

pages = {673--682.e4},

abstract = {Animals employ active touch to optimize the acuity of their tactile sensors. Prior experimental results and models lead to the hypothesis that sensory inputs are used in a recurrent manner to tune the position of the sensors. A combination of electrophysiology, intersectional genetic viral labeling and manipulation, and classical tracing allowed us to identify second-order sensorimotor loops that control vibrissa movements by rodents. Facial motoneurons that drive intrinsic muscles to protract the vibrissae receive a short latency inhibitory input, followed by synaptic excitation, from neurons located in the oralis division of the trigeminal sensory complex. In contrast, motoneurons that retract the mystacial pad and indirectly retract the vibrissae receive only excitatory input from interpolaris cells that further project to the thalamus. Silencing this feedback alters retraction. The observed pull-push circuit at the lowest-level sensorimotor loop provides a mechanism for the rapid modulation of vibrissa touch during exploration of peri-personal space.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28216320,

title = {Coordination of Orofacial Motor Actions into Exploratory Behavior by Rat},

author = {Anastasia Kurnikova and Jeffrey D Moore and Song-Mao Liao and Martin Deschênes and David Kleinfeld},

doi = {10.1016/j.cub.2017.01.013},

issn = {1879-0445},

year  = {2017},

date = {2017-03-01},

journal = {Curr Biol},

volume = {27},

number = {5},

pages = {688--696},

abstract = {The delineation of sensorimotor circuits that guide exploration begins with an understanding of the pattern of motor outputs [1]. These motor patterns provide a clue to the form of the underlying circuits [2-4] (but see [5]). We focus on the behaviors that rodents use to explore their peripersonal space through goal-directed positioning of their nose, head, and vibrissae. Rodents sniff in response to novel odors, reward expectation, and as part of social interactions [6-12]. Sniffing serves olfaction [13, 14], while whisking synchronized to sniffing serves vibrissa-based touch [6, 15, 16]. We quantify the ethology of exploratory nose and head movements in relation to breathing. We find that sniffing is accompanied by prominent lateral and vertical deflections of the nose, i.e., twitches, which are driven by activation of the deflector nasi muscles [17]. On the timescale of individual breaths, nose motion is rhythmic and has a maximum deflection following the onset of inspiration. On a longer timescale, excursions of the nose persist for several breaths and are accompanied by an asymmetry in vibrissa positioning toward the same side of the face. Such directed deflections can be triggered by a lateralized source of odor. Lastly, bobbing of the head as the animal cranes and explores is phase-locked to sniffing and to movement of the nose. These data, along with prior results on the resetting of the whisk cycle at the onset of inspiration [15, 16, 18], reveal that the onset of each breath initiates a "snapshot" of the orofacial sensory environment. VIDEO ABSTRACT.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27041498,

title = {Inhibition, Not Excitation, Drives Rhythmic Whisking},

author = {Martin Deschênes and Jun Takatoh and Anastasia Kurnikova and Jeffrey D Moore and Maxime Demers and Michael Elbaz and Takahiro Furuta and Fan Wang and David Kleinfeld},

doi = {10.1016/j.neuron.2016.03.007},

issn = {1097-4199},

year  = {2016},

date = {2016-04-01},

journal = {Neuron},

volume = {90},

number = {2},

pages = {374--387},

abstract = {Sniffing and whisking typify the exploratory behavior of rodents. These actions involve separate oscillators in the medulla, located respectively in the pre-Bötzinger complex (preBötC) and the vibrissa-related region of the intermediate reticular formation (vIRt). We examine how these oscillators synergize to control sniffing and whisking. We find that the vIRt contains glycinergic/GABAergic cells that rhythmically inhibit vibrissa facial motoneurons. As a basis for the entrainment of whisking by breathing, but not vice versa, we provide evidence for unidirectional connections from the preBötC to the vIRt. The preBötC further contributes to the control of the mystacial pad. Lastly, we show that bilateral synchrony of whisking relies on the respiratory rhythm, consistent with commissural connections between preBötC cells. These data yield a putative circuit in which the preBötC acts as a master clock for the synchronization of vibrissa, pad, and snout movements, as well as for the bilateral synchronization of whisking.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}