Tonic Firing Rate Research Articles

Tonic sensory pathways of the respiratory system

Both respiratory centres and the preganglionic vagal motoneurones, which control respiratory (striated) and airway (smooth) muscles respectively, receive information on the lungs, the circulation and the skeletal and respiratory muscles. Each of these nervous pathways has two components: one is phasic, i.e. in phase with biological rhythms, and comes from mechanoreceptors connected to large myelinated fibres; the second has a tonic low frequency firing rate and corresponds to the spontaneous activity of polymodal receptors connected to thin sensory fibres, which act mostly as sensors of changes in extracellular fluid composition (O2 and/or CO2 partial pressure, pH, release of algesic agents etc...). Some of them also detect large mechanical disturbances or local temperature changes. The influence of tonic background sensory activity is well known in animals concerning the role played by arterial chemoreceptors in the control of ventilation and of thin vagal afferents from the lungs (bronchopulmonary C-fibres and irritant receptors) in reflex facilitation of the bronchoconstrictor vagal tone. Moreover, the stimulation of thin sensory fibres in particular circumstances is responsible for hyperventilation (arterial chemoreceptors and muscle afferents), increased airway tone (arterial chemoreceptors and mostly thin vagal afferent fibres) or bronchodilation (muscle afferents). These peripheral inputs project centrally on different structures and also on brain stem neurones, which integrate simultaneously chemosensory, vagal and muscle information. This results in complex interactions between the different sensory pathways.

Anatomical and physiological characteristics of vestibular neurons mediating the vertical vestibulo-ocular reflexes of the squirrel monkey.

The morphology of 35 vestibular neurons whose firing rate was related to vertical eye movements was studied by injection of horseradish peroxidase intracellularly into physiologically identified vestibular axons in alert squirrel monkeys. The intracellularly injected cells were readily classified into four main groups. One group of cells, down position-vestibular-pause neurons (down PVPs; N = 12), increased their firing rate during downward eye positions, paused during saccades, and were located in the medial vestibular nucleus (MV) and the adjacent ventrolateral vestibular nucleus (VLV). They had axons that crossed the midline and ascended in the medial longitudinal fasciculus (MLF) to terminate in the trochlear nucleus, the lateral aspect of the caudal oculomotor nucleus, and the dorsal aspect of the rostral oculomotor nucleus. A second group of cells (N = 15) were also located in the MV and VLV, but increased their firing rate during upward eye positions, and paused during saccades. These cells had axons that crossed the midline and ascended in the contralateral MLF to terminate in the medial aspect of the oculomotor nucleus. A third group of cells (N = 4) were located in the superior vestibular nucleus, generated bursts of spikes during upward saccades, and increased their tonic firing rate during upward eye positions. These cells had axons that ascended laterally to the ipsilateral MLF to terminate in regions of the trochlear and oculomotor nuclei similar to those in which down PVPs terminated. A fourth group of cells (N = 4), located in the VLV, had axons that projected to the spinal cord, although they had firing rates that were significantly correlated with vertical eye position. Electrical stimulation of the vestibular nerve evoked spikes at monosynaptic latencies in each of the above classes of cells, six of which were injected with horseradish peroxidase. Each group of cells had collateral projections to other areas of the brainstem. Some of the neurons that projected to the contralateral trochlear and oculomotor nuclei had collaterals that crossed the midline to terminate in the oculomotor nucleus ipsilateral to the soma, and some gave rise to small collaterals that terminated in the abducens nucleus. Other areas of the brainstem that received collateral inputs from neurons projecting to oculomotor and trochlear nuclei included the interstitial nucleus of Cajal, the caudal part of the dorsal raphe nucleus, the nucleus raphe obscurus, Roller's nucleus, the intermediate and caudal interstitial nuclei of the MLF, and the nucleus prepositus.

Anatomical and physiological characteristics of vestibular neurons mediating the horizontal vestibulo-ocular reflex of the squirrel monkey.

The anatomical characteristics of vestibular neurons, which are involved in controlling the horizontal vestibulo-ocular reflex, were studied by injecting horseradish peroxidase (HRP) into neurons whose response during spontaneous eye movements had been characterized in alert squirrel monkeys. Most of the vestibular neurons injected with HRP that had axons projecting to the abducens nucleus or the medial rectus subdivision of the oculomotor nucleus had discharge rates related to eye position and eye velocity. Three morphological types of cells were injected whose firing rates were related to horizontal eye movements. Two of the cell types were located in the ventral lateral vestibular nucleus and the ventral part of the medial vestibular nucleus (MV). These vestibular neurons could be activated at monosynaptic latencies following electrical stimulation of the vestibular nerve; increased their firing rate when the eye moved in the direction contralateral to the soma; had tonic firing rates that increased when the eye was held in contralateral positions; and had a pause in their firing rate during saccadic eye movements in the ipsilateral or vertical directions. Eleven of the above cells had axons that arborized exclusively on the contralateral side of the brainstem, terminating in the contralateral abducens nucleus, the dorsal paramedian pontine reticular formation, the prepositus nucleus, medial vestibular nucleus, dorsal medullary reticular formation, caudal interstitial nucleus of the medial longitudinal fasciculus, and raphé obscurus. Eight of the cells had axons that projected rostrally in the ascending tract of Deiters and arborized exclusively on the ipsilateral side of the brainstem, terminating in the ipsilateral medial rectus subdivision of the oculomotor nucleus and, in some cases, the dorsal paramedian pontine reticular formation or the caudal interstitial nucleus of the medial longitudinal fasciculus. Two MV neurons were injected that had discharge rates related to ipsilateral eye position, generated bursts of spikes during saccades in the ipsilateral direction, and paused during saccades in the contralateral direction. The axons of those cells arborized ipsilaterally, and terminated in the ipsilateral abducens nucleus, MV, prepositus nucleus, and the dorsal medullary reticular formation. The morphology of vestibular neurons that projected to the abducens nucleus whose discharge rate was not related to eye movements, or was related primarily to vertical eye movements, is also briefly presented.

Neural control of vergence eye movements: neurons encoding vergence velocity.

Single-unit recordings were made from midbrain areas in monkeys trained to make both conjugate and disjunctive (vergence) eye movements. Previous work had identified cells with a firing rate proportional to the vergence angle, without regard to the direction of conjugate gaze. The present study describes the activity of neurons that burst for disjunctive eye movements. Convergence burst cells display a discrete burst of activity just before and during convergence eye movements. For most of these cells, the profile of the burst is correlated with instantaneous vergence velocity and the number of spikes in the burst is correlated with the size of the vergence movement. Some of these cells also have a tonic firing rate that is positively correlated with vergence angle (convergence burst-tonic cells). Divergence burst cells have similar properties, except that they fire for divergent and not convergent movements. Divergence burst cells are encountered far less often than convergence burst cells. Both convergence and divergence burst cells were found in an area of the mesencephalic reticular formation just dorsal and lateral to the oculomotor nucleus. Convergence burst cells were also recorded in another more dorsal mesencephalic region, rostral to the superior colliculus. Both of the areas also contain cells that encode vergence angle. Models of the vergence system derived from psychophysical data imply the existence of a vergence integrator, the output of which is vergence angle. Some models also suggest the presence of a parallel element that improves the frequency response of the vergence system, but has no effect on the steady-state behavior of the system. Vergence burst cells would be suitable inputs to a vergence integrator. By providing a vergence velocity signal to motoneurons, they may improve the dynamic response of the vergence system. The behavior of vergence burst cells during vergence movements is similar to that of the medium-lead burst cells during saccades. The proposed roles for vergence velocity cells are analogous to those of the saccadic burst cells. In this respect, the neural organization of the vergence system resembles that of the saccadic system, despite the distinct difference in the kinematics of these two types of eye movements.

Role of the monkey substantia nigra pars reticulata in orienting behaviour and visually triggered arm movements

The role of the substantia nigra pars reticulata (SNpr) has been studied in the head-free monkey during orienting behaviour in response to visual instruction signals triggering head positioning and conditioned arm movement. During the behavioural responses we recorded the electromyographic activities of neck muscles and triceps brachii, head movement, horizontal electrooculogram and single unit activity of SNpr neurons. Activity of 38 neurons located in the medial part of SNpr were analysed during the visuo-motor task. Forty percent of these units showed a moderate decrease in tonic firing rate during postural preparation preceding the orientation toward eccentric visual signal. This decrease, unrelated with saccadic eye movements per se, was followed by a marked pause observed when the rewarded stimulus was switched on and the conditioned arm movement was executed to get the reward. These data suggest that the pause in discharge of these SNpr neurons are time locked with behaviourally relevant visual stimuli and or appropriate motor responses.

中脳ネコの制御歩行，足踏み動作および反射直立姿勢時における外側前庭神経核細胞の機能的役割

Stimulation delivered to the mesencephalic locomotor region (MLR) in the acute decerebrate cat elicits “controlled” locomotion on a moving treadmill. Stimulation to the dorsolateral part of the MLR elicits alternating rhythmic shifting of the weight between hindlimbs (stepping) on a still surface. Stimulation to the MLR increases postural muscle tone of the hindlimbs augenting reflex standing of a decerebrate cat.The changes in the discharge characteristics of 84 neurons in the lateral vestibular nucleus (VLD-neurons) were studied during these locomotor movements and postural changes. VLD-neurons were antidromically identified and extracellularly recorded by means of microelectrodes. EMGs of representative hindlimb muscles were recorded. During hindlimb stepping and postural changes, the forces exerted at the foot contacts of the hindlimbs were measured by means of force transducers.The results obtained from 84 VLD-neurons (conduction velocity : 93.1±17.8m/s, firing rate : 12.1±11.5spikes/s) are summarized as follows : 1) With shortening of the cycle time during locomotion, the majority of VLD-neurons (43/54) tended to discharge rhythmically in phase with bursting discharges of the triceps surae muscle. The rest of the VLD-neurons (11/54) maintained tonic discharges irrespective of the changes in cycle time. 2) During hindlimb stepping, some VLD-neurons (8/16) exhibited rhythmic bursting discharges slightly preceding the onset of force increase in the ipsilateral hindlimb. 3) Most VLD-neurons (17/18) increased their tonic firing rates during augmented reflex standing.All these results demonstrate that VLD-neurons play roles not only in the phase contral system but also in the power or postural tone control system both during locomotor movements and postural adjustments.

Operant conditioning of single unit activity in parietal cortex

Two rhesus monkeys were trained to control firing patterns of single neurons in parietal cortex (areas 1, 2, 3, 5, 7) using an operant task previously applied to the study of precental units. Twenty-four of 56 (43%) postcentral cells were controlled in contrast to 71 of 136 (52%) precentral units from these and 4 other rhesus monkeys. In addition, monkeys were able to drive precentral units to more sustained tonic firing rates than they could parietal units. An analysis of interspike interval (ISI) distributions showed that, in contrast to precentral units with modal ISIs of 25–50 ms, 50% of parietal units have modal ISIs of 2 ms. Such short ISIs may account for fewer postcentral units reaching control criteria for this particular operant task. Other factors that may contribute to the reduced control of postcentral cells are discussed, particularly the more complex afferent connections to parietal units when compared to precentral pyramidal tract neurons. The data indirectly support conclusions from previous studies that imply that operant control of cortical units is peripherally mediated and does not primarily involve a ‘central’ or ‘open loop’ system.

Simple spike activity of Purkinje cells in the posterior vermis of awake cats during spontaneous saccadic eye movements

Extracellular recordings were made from 151 cerebellar cortical cells in the posterior vermis of 12 awake cats. Thirty-two percent ( n=48) of these cells modulated their activity with respect to the onset of spontaneous saccadic eye movements. Thirty-five cells in this group were positively identified as Purkinje cells and manifested changes in simple spike activity that were related to saccade onset. These included short excitatory, inhibitory, or biphasic changes that were superimposed on background tonic firing rates ( avg.=54 spikes/sec). Such changes were recorded before as well as after the onset of a saccade. Sixty-five percent ( n=22) of these cells were related to horizontal and vertical saccades in more than one direction of motion. These cells were randomly distributed throughout the posterior vermis and manifested no anatomical topographic organization with respect to the direction of saccadic eye movement. The results of this study suggest that lobules VI and VII of the cerebellar vermis participate in both the initiation and execution of spontaneous saccades in preferred directions.

Discharge patterns of basal ganglia neurons during active maintenance of postural stability and adjustment to chair tilt

Neurons in the putamen and globus pallidus were studied in awake monkeys making active postural adjustments during static and dynamic chair tilt. When the chair was held horizontal and the monkey actively maintained a restricted head position, neurons had tonic firing rates similar to those described previously, with low frequency patterns in the putamen and low frequency-burst or intermediate (IFD) to high frequency (HFD) tonic patterns in neurons in the pallidal segments. Over half of the neurons with IFD or HFD discharge rates and a smaller proportion of those with slow discharge rates showed changes in firing that were temporally correlated with chair tilt. Phase shifts of firing frequency relative to sinusoidally varied chair position varied in units with different tonic discharge frequencies. Maximum and minimum discharge rates in IFD neurons occured near maximum chair velocities, whereas the phase shift decreased in HFD neurons, which had higher discharge rates during the horizontal chair position. Neurons with changes in discharge during chair tilt were found in all portions of the putamen and globus pallidus studied.

Operant conditioning of tonic neuronal firing rates from single units in monkey motor cortex

Operant conditioning of tonic neuronal firing rates from single units in monkey motor cortex

Peripheral factors contributing to the volitional control of firing rates of the human motor units

Human subjects can volitionally control discharge frequencies of isolated motor units at several frequencies. If the tonic firing rates such as 10 Hz are mainly dependent on the gamma-loop and if Xylocaine blocks gamma-fibers before blocking alpha-fibers, application of Xylocaine would preferentially disturb the tonic rates. After application of Xylocaine to the nerve innervating the motor units the tonic discharges at 10 Hz became irregular, while the phasic discharges at 1 Hz could still be performed volitionally. These results suggest that volitional control of tonic discharges of the motor units are dependent upon gamma activity, while the phasic discharges may be controlled by the impulses along the pyramidal tracts.

Inhibitory processes and interneuronal apparatus in motor cortex during sleep and waking. I. Background firing and responsiveness of pyramidal tract neurons and interneurons.

Inhibitory processes and interneuronal apparatus in motor cortex during sleep and waking. I. Background firing and responsiveness of pyramidal tract neurons and interneurons.

Operantly conditioned patterns on precentral unit activity and correlated responses in adjacent cells and contralateral muscles.

Operantly conditioned patterns on precentral unit activity and correlated responses in adjacent cells and contralateral muscles.E E Fetz, and M A BakerE E Fetz, and M A BakerPublished Online:01 Mar 1973https://doi.org/10.1152/jn.1973.36.2.179MoreSectionsPDF (4 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByA rodent brain-machine interface paradigm to study the impact of paraplegia on BMI performanceJournal of Neuroscience Methods, Vol. 306Brain-machine interfaces for rehabilitation in stroke: A reviewNeuroRehabilitation, Vol. 43, No. 1Mental causation via neuroprosthetics? 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Schieber15 September 2014 | Journal of Neurophysiology, Vol. 112, No. 6Operant Conditioning of Primate Prefrontal NeuronsShunsuke Kobayashi, Wolfram Schultz, and Masamichi Sakagami1 April 2010 | Journal of Neurophysiology, Vol. 103, No. 4Optimizing a Linear Algorithm for Real-Time Robotic Control using Chronic Cortical Ensemble Recordings in MonkeysJournal of Cognitive Neuroscience, Vol. 16, No. 6Learning to Control a Brain–Machine Interface for Reaching and Grasping by Primates13 October 2003 | PLoS Biology, Vol. 1, No. 2Brain–machine interfaces to restore motor function and probe neural circuits1 May 2003 | Nature Reviews Neuroscience, Vol. 4, No. 5Cortical motor areas and their properties: Implications for neuroprostheticsRestoration of neural output from a paralyzed patient by a direct brain connectionNeuroReport, Vol. 9, No. 8Frontal lobesCurrent Opinion in Neurobiology, Vol. 3, No. 2The cone electrode: a long-term electrode that records from neurites grown onto its recording surfaceJournal of Neuroscience Methods, Vol. 29, No. 3Operant conditioning in motor and neural integrationNeuroscience & Biobehavioral Reviews, Vol. 10, No. 4Synchrony between cortical neurons during operant conditioningBrain Research, Vol. 341, No. 1Operant conditioning of somatosensory evoked potential (SEP) amplitude in rats. II. Associated changes in reflex and continuous non-timelocked movementsBrain Research, Vol. 333, No. 2Interneuronal synchrony in precentral cortex of monkeys during operant conditioningExperimental Neurology, Vol. 80, No. 3Evolution of myoelectrical and precentral cell activities during learning of a new amplitude of movementBrain Research, Vol. 267, No. 2Short-term changes in cell activity of areas 4 and 5 during operant conditioningExperimental Neurology, Vol. 78, No. 2Operant control of precentral neurons: Bilateral single unit conditioningBrain Research, Vol. 195, No. 2Operant control of precentral neurons: Control of modal interspike intervalsBrain Research, Vol. 190, No. 1Operant control of precentral neurons in monkeys: Evidence against open loop controlBrain Research, Vol. 171, No. 1Evidence for a transcortical reflex: primate corticospinal tract neuron response to ramp stretch of muscleBrain Research, Vol. 159, No. 2Operant control of pyramidal tract neurons: The role of spinal dorsal columnsBrain Research, Vol. 157, No. 2Fine control of operantly conditioned firing patterns of cortical neuronsExperimental Neurology, Vol. 61, No. 2Factors influencing accuracy of operant control of pyramidal tract neurons in monkeyBrain Research, Vol. 152, No. 2Epileptic and normal neurons in monkey neocortex: A quantitative study of degree of operant controlBrain Research, Vol. 151, No. 2Operant conditioning of tonic firing patterns from precentral neurons in monkey neocortexBrain Research, Vol. 146, No. 1Responses of single units in cervical spinal cord of alert monkeysExperimental Neurology, Vol. 55, No. 2Operant conditioning of tonic neuronal firing rates from single units in monkey motor cortexBrain Research, Vol. 117, No. 3Response properties of distinct neuronal subsets in hindlimb sensorimotor cerebral cortex of the domestic catExperimental Neurology, Vol. 53, No. 2Firing patterns of epileptic and normal neurons in the chronic alumina focus in undrugged monkeys during different behavioral statesBrain Research, Vol. 98, No. 1An electronic activity integrator for operant conditioning of patterns of neural and muscular activityElectroencephalography and Clinical Neurophysiology, Vol. 38, No. 1Effects of operantly conditioning epileptic unit activity on seizure frequencies and electrophysiology of neocortical experimental fociExperimental Neurology, Vol. 44, No. 1Distributed feedback systems for muscle controlBrain Research, Vol. 71, No. 2-3Behavioral control of firing patterns of normal and abnormal neurons in chronic epileptic cortexExperimental Neurology, Vol. 42, No. 2Operantly conditioned firing patterns of epileptic neurons in the monkey motor cortexExperimental Neurology, Vol. 40, No. 3Are We the Robots? More from this issue > Volume 36Issue 2March 1973Pages 179-204 https://doi.org/10.1152/jn.1973.36.2.179PubMed4196269History Published online 1 March 1973 Published in print 1 March 1973 Metrics

Changes in unit activity and thresholds to electrical microstimulation at coronal-pericruciate cortex of cat with classical conditioning of different facial movements.

Changes in unit activity and thresholds to electrical microstimulation at coronal-pericruciate cortex of cat with classical conditioning of different facial movements.C D Woody, and J Engel JrC D Woody, and J Engel JrPublished Online:01 Mar 1972https://doi.org/10.1152/jn.1972.35.2.230MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByReverse Effects of Conditioning Produced by Two Different Unconditioned Stimuli on Thalamocortical TransmissionEl Mehdi Meftah, and Lucie Rispal-Padel1 April 1997 | Journal of Neurophysiology, Vol. 77, No. 4Physiological motor asymmetry in human handedness: evidence from transcranial magnetic stimulationBrain Research, Vol. 636, No. 2Selective form of an excitable membrane plasticityBrain Research, Vol. 595, No. 1Changes in membrane currents during Pavlovian conditioning of single cortical neuronsBrain Research, Vol. 539, No. 1Pavlovian conditioning of discriminatively elicited eyeblink responses with short onset latency attributable to lengthened interstimulus intervalsBrain Research, Vol. 400, No. 1Intracellular injection of cGMP-dependent protein kinase results in increased input resistance in neurons of the mammalian motor cortexBrain Research, Vol. 386, No. 1-2Responses of morphologically identified cortical neurons to intracellularly injected cyclic GMPExperimental Neurology, Vol. 91, No. 3Neuronal responses of the rabbit brainstem during performance of the classically conditioned nictitating membrane (NM)/eyelid responseBrain Research, Vol. 271, No. 1Concomitant classical conditioning of the rabbit nictitating membrane and eyelid responses: Correlations and implicationsPhysiology & Behavior, Vol. 28, No. 5Characterization of electrophysiological properties of intracellularly recorded neurons in the neocortex of awake cats: A comparison of the response to injected current in spike overshoot and undershoot neuronsBrain Research, Vol. 158, No. 2Effects of acetylcholine and cyclic GMP on input resistance of cortical neurons in awake catsBrain Research, Vol. 158, No. 2Changes in cortical neuronal excitability after presentations of a compound auditory stimulusBrain Research, Vol. 156, No. 1Operant conditioning of tonic firing patterns from precentral neurons in monkey neocortexBrain Research, Vol. 146, No. 1Changes in evoked activity of precentral neurons associated with single unit operant conditioningBrain Research, Vol. 124, No. 3Operant conditioning of tonic neuronal firing rates from single units in monkey motor cortexBrain Research, Vol. 117, No. 3Intracellular study of auditory evoked activity in pericruciate cortex of the awake, non-paralyzed catBrain Research, Vol. 85, No. 1Acquisition of a conditioned eyeblink response during reversible denervation of orbicularis oculi muscles in the catBrain Research, Vol. 64Application of optimum linear filter theory to the detection of cortical signals preceding facial movement in cat1 March 1973 | Experimental Brain Research, Vol. 16, No. 5 More from this issue > Volume 35Issue 2March 1972Pages 230-41 https://doi.org/10.1152/jn.1972.35.2.230PubMed5028660History Published online 1 March 1972 Published in print 1 March 1972 Metrics