Input-output organization of inhibitory neurons in the interstitial nucleus of Cajal projecting to the contralateral trochlear and oculomotor nucleus

2013 ◽  
Vol 110 (3) ◽  
pp. 640-657 ◽  
Author(s):  
Y. Sugiuchi ◽  
M. Takahashi ◽  
Y. Shinoda
Keyword(s):  
Head Movements ◽  
Input Output ◽  
Oculomotor Nucleus ◽  
Inferior Rectus ◽  
Interstitial Nucleus Of Cajal ◽  
Vertical Saccades ◽  
Disynaptic Inhibition ◽  
Forel's Field H ◽  
Trochlear Nucleus ◽  
Monosynaptic Excitation

Neurons in the interstitial nucleus of Cajal (INC) that are known to be involved in eye and head movements are excitatory. We investigated the input-output organization of inhibitory INC neurons involved in controlling vertical saccades. Intracellular recordings were made in INC neurons activated antidromically by stimulation of the contralateral trochlear or oculomotor nucleus, and their synaptic input properties from the superior colliculi (SCs) and the contralateral INC were analyzed in anesthetized cats. Many INC neurons projected to the contralateral trochlear nucleus, Forel's field H, INC, and oculomotor nucleus, and mainly received monosynaptic excitation followed by disynaptic inhibition from the ipsi- and contralateral SCs. After sectioning the commissural connections between the SCs, these neurons received monosynaptic excitation from the ipsilateral medial SC and disynaptic inhibition via the INC from the contralateral lateral SC. Another group of INC neurons were antidromically activated from the contralateral oculomotor nucleus, INC and Forel's field H, but not from the trochlear nucleus, and received monosynaptic excitation from the ipsilateral lateral SC and disynaptic inhibition from the contralateral medial SC. The former group was considered to inhibit contralateral trochlear and inferior rectus motoneurons in upward saccades, whereas the latter was considered to inhibit contralateral superior rectus and inferior oblique motoneurons in downward saccades. The mutual inhibition existed between these two groups of INC neurons for upward saccades on one side and downward saccades on the other. This pattern of input-output organization of inhibitory INC neurons suggests that the basic neural circuits for horizontal and vertical saccades are similar.

Neural Organization of the Pathways From the Superior Colliculus to Trochlear Motoneurons

2007 ◽  
Vol 97 (5) ◽  
pp. 3696-3712 ◽  
Author(s):  
Yoshiko Izawa ◽  
Yuriko Sugiuchi ◽  
Yoshikazu Shinoda
Keyword(s):  
Superior Colliculus ◽  
Interstitial Nucleus Of Cajal ◽  
Saccadic System ◽  
Neural Organization ◽  
Premotor Neurons ◽  
Monosynaptic Inhibition ◽  
Disynaptic Inhibition ◽  
Forel's Field H ◽  
Stimulation Of ◽  
Monosynaptic Excitation

The neural organization of the pathways from the superior colliculus (SC) to trochlear motoneurons was analyzed in anesthetized cats using intracellular recording and transneuronal labeling techniques. Stimulation of the ipsilateral or contralateral SC evoked excitation and inhibition in trochlear motoneurons with latencies of 1.1–2.3 and 1.1–3.8 ms, respectively, suggesting that the earliest components of excitation and inhibition were disynaptic. A midline section between the two SCs revealed that ipsi- and contralateral SC stimulation evoked disynaptic excitation and inhibition in trochlear motoneurons, respectively. Premotor neurons labeled transneuronally after application of wheat germ agglutinin-conjugated horseradish peroxidase into the trochlear nerve were mainly distributed ipsilaterally in the Forel's field H (FFH) and bilaterally in the interstitial nucleus of Cajal (INC). Consequently, we investigated these two likely intermediaries between the SC and trochlear nucleus electrophysiologically. Stimulation of the FFH evoked ipsilateral mono- and disynaptic excitation and contralateral disynaptic inhibition in trochlear motoneurons. Preconditioning stimulation of the ipsilateral SC facilitated FFH-evoked monosynaptic excitation. Stimulation of the INC evoked ipsilateral monosynaptic excitation and inhibition, and contralateral monosynaptic inhibition in trochlear motoneurons. Preconditioning stimulation of the contralateral SC facilitated contralateral INC-evoked monosynaptic inhibition. These results revealed a reciprocal input pattern from the SCs to vertical ocular motoneurons in the saccadic system; trochlear motoneurons received disynaptic excitation from the ipsilateral SC via ipsilateral FFH neurons and disynaptic inhibition from the contralateral SC via contralateral INC neurons. These inhibitory INC neurons were considered to be a counterpart of inhibitory burst neurons in the horizontal saccadic system.

Vertical eye movement-related secondary vestibular neurons ascending in medial longitudinal fasciculus in cat. II. Direct connections with extraocular motoneurons

1990 ◽  
Vol 63 (4) ◽  
pp. 918-935 ◽  
Author(s):  
Y. Iwamoto ◽  
T. Kitama ◽  
K. Yoshida
Keyword(s):  
Rectus Muscle ◽  
Medial Longitudinal Fasciculus ◽  
Field Potentials ◽  
Oculomotor Nucleus ◽  
Inferior Rectus ◽  
Interstitial Nucleus Of Cajal ◽  
Excitatory Connection ◽  
Superior Rectus ◽  
Spike Triggered Averaging ◽  
Trochlear Nucleus

1. The preceding study in the alert cat has shown that many secondary vestibular axons that ascend in the medial longitudinal fasciculus (MLF) increase their firing rate in proportion to downward eye position. In the present study, projection and termination of these downward-position-vestibular (DPV) neurons within extraocular motoneuron pools were studied electrophysiologically by spike-triggered averaging techniques and morphologically be reconstructing their axonal trajectory after intra-axonal injection of horseradish peroxidase (HRP). 2. Extracellular field potentials recorded within the trochlear nucleus and/or the inferior rectus subdivision of the oculomotor nucleus were averaged by the use of spike potentials of single DPV neurons as triggers. All the crossed-DPV axons tested induced negative unitary field potentials in the trochlear nucleus (n = 9) and in the inferior rectus subdivision of the oculomotor nucleus (n = 5), suggesting that they made monosynaptic excitatory connection with motoneurons in these nuclei. The four crossed-DPV axons tested in the two motoneuron pools induced unitary field potentials in both. The majority of crossed-DPV axons terminated in these nuclei were directly activated from the caudal MLF, indicating that they had descending collaterals projecting to the spinal cord as well. The uncrossed-DPV axons did not induce such unitary field potentials either in the trochlear nucleus (n = 4) or in the inferior rectus subdivision (n = 3). 3. All the uncrossed-DPV axons examined (n = 14) induced positive unitary field potentials in the superior rectus subdivision of the oculomotor nucleus, suggesting that they made monosynaptic inhibitory connections with motoneurons innervating the superior rectus muscle. These uncrossed-DPV axons displayed regular firing patterns and were not activated from the caudal MLF. None of the crossed-DPV axons tested (n = 4) induced unitary field potentials in the superior rectus subdivision. 4. Five crossed-DPV axons were injected with HRP. All these axons ascended in the MLF contralateral to their soma, gave off many collaterals to the trochlear nucleus, and projected more rostrally. For three well-stained axons, numerous terminal branches were also found in the rostroventral part of the contralateral oculomotor nucleus, the area corresponding to the inferior rectus subdivision. Some collaterals in the oculomotor nucleus recrossed the midline to terminate in the medial part of the ipsilateral oculomotor nucleus. Other terminations were observed in the interstitial nucleus of Cajal and in the periaqueductal gray adjacent to the oculomotor nucleus. The crossed axons injected included both regular and irregular types, and three of the four examined were activated from the caudal MLF.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Identification of Brain Electrical Activity Related to Head Yaw Rotations

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3345
Author(s):  
Enrico Zero ◽  
Chiara Bersani ◽  
Roberto Sacile
Keyword(s):  
Electrical Activity ◽  
Electrical Stimulus ◽  
Head Movements ◽  
Brain Electrical Activity ◽  
Output Function ◽  
Input Output ◽  
Eeg Signals ◽  
Head Turning ◽  
Identification Technique ◽  
The Brain

Automatizing the identification of human brain stimuli during head movements could lead towards a significant step forward for human computer interaction (HCI), with important applications for severely impaired people and for robotics. In this paper, a neural network-based identification technique is presented to recognize, by EEG signals, the participant’s head yaw rotations when they are subjected to visual stimulus. The goal is to identify an input-output function between the brain electrical activity and the head movement triggered by switching on/off a light on the participant’s left/right hand side. This identification process is based on “Levenberg–Marquardt” backpropagation algorithm. The results obtained on ten participants, spanning more than two hours of experiments, show the ability of the proposed approach in identifying the brain electrical stimulus associate with head turning. A first analysis is computed to the EEG signals associated to each experiment for each participant. The accuracy of prediction is demonstrated by a significant correlation between training and test trials of the same file, which, in the best case, reaches value r = 0.98 with MSE = 0.02. In a second analysis, the input output function trained on the EEG signals of one participant is tested on the EEG signals by other participants. In this case, the low correlation coefficient values demonstrated that the classifier performances decreases when it is trained and tested on different subjects.

Activity of Mesencephalic Vertical Burst Neurons During Saccades and Smooth Pursuit

2000 ◽  
Vol 83 (4) ◽  
pp. 2080-2092 ◽  
Author(s):  
M. Missal ◽  
S. de Brouwer ◽  
P. Lefèvre ◽  
E. Olivier
Keyword(s):  
Vertical Velocity ◽  
Smooth Pursuit ◽  
Medial Longitudinal Fasciculus ◽  
Eye Position ◽  
Interstitial Nucleus Of Cajal ◽  
Burst Neurons ◽  
Preferred Direction ◽  
Saccade Onset ◽  
Vertical Saccades ◽  
Eye Velocity

The activity of vertical burst neurons (BNs) was recorded in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF-BNs) and in the interstitial nucleus of Cajal (NIC-BNs) in head-restrained cats while performing saccades or smooth pursuit. BNs emitted a high-frequency burst of action potentials before and during vertical saccades. On average, these bursts led saccade onset by 14 ± 4 ms (mean ± SD, n = 23), and this value was in the range of latencies (∼5–15 ms) of medium-lead burst neurons (MLBNs). All NIC-BNs ( n = 15) had a downward preferred direction, whereas riMLF-BNs showed either a downward ( n = 3) or an upward ( n = 5) preferred direction. We found significant correlations between saccade and burst parameters in all BNs: vertical amplitude was correlated with the number of spikes, maximum vertical velocity with maximum of the spike density, and saccade duration with burst duration. A correlation was also found between instantaneous vertical velocity and neuronal activity during saccades. During fixation, all riMLF-BNs and ∼50% of NIC-BNs (7/15) were silent. Among NIC-BNs active during fixation (8/15), only two cells had an activity correlated with the eye position in the orbit. During smooth pursuit, most riMLF-BNs were silent (7/8), but all NIC-BNs showed an activity that was significantly correlated with the eye velocity. This activity was unaltered during temporary disappearance of the visual target, demonstrating that it was not visual in origin. For a given neuron, its on-direction during smooth pursuit and saccades remained identical. The activity of NIC-BNs during both saccades and smooth pursuit can be described by a nonlinear exponential function using the velocity of the eye as independent variable. We suggest that riMLF-BNs, which were not active during smooth pursuit, are vertical MLBNs responsible for the generation of vertical saccades. Because NIC-BNs discharged during both saccades and pursuit, they cannot be regarded as MLBNs as usually defined. NIC-BNs could, however, be the site of convergence of both the saccadic and smooth pursuit signals at the premotoneuronal level. Alternatively, NIC-BNs could participate in the integration of eye velocity to eye position signals and represent input neurons to a common integrator.

The vestibuloocular reflex of the adult flatfish. II. Vestibulooculomotor connectivity

1985 ◽  
Vol 54 (4) ◽  
pp. 900-916 ◽  
Author(s):  
W. Graf ◽  
R. Baker
Keyword(s):  
Vestibular Nucleus ◽  
Medial Longitudinal Fasciculus ◽  
Vestibuloocular Reflex ◽  
Oculomotor Nucleus ◽  
Inferior Rectus ◽  
Ipsilateral Side ◽  
Horizontal Canal ◽  
Superior Rectus ◽  
First Case ◽  
Target Sites

The peripheral and central oculomotor organization of the adult flatfish presents no morphological substrates that suffice to explain adaptive changes in its vestibuloocular reflex system. The necessity for an adaptation occurs because of a 90 degrees displacement of the vestibular with respect to the extraocular coordinate axes during metamorphosis. Since a reorganization of vestibuloocular pathways must be hypothesized (12), the location and termination of electrophysiologically identified secondary vestibular neurons with focus on the horizontal canal system was studied with the intracellular horseradish peroxidase method in adult winter flounders. Pseudopleuronectes americanus. The oculomotor target sites of vertical canal related neurons were similar to those described in mammals. Presumed excitatory anterior canal neurons bifurcated after the main axon had crossed the midline. The descending branch headed toward the spinal cord. The ascending branch reached the oculomotor nucleus via the contralateral medial longitudinal fasciculus and terminated in the superior rectus and inferior oblique subdivisions. Presumed inhibitory posterior canal neurons ascended ipsilaterally in the medial longitudinal fasciculus and terminated mainly in the superior rectus and inferior oblique subdivisions. Horizontal canal neurons exhibited characteristics distinctly different from mammalian ones. Two types of second-order neurons were observed. In the first case, cell bodies were located in the anterior portion of the vestibular nuclear complex. After crossing the midline, the axon ascended in the contralateral medial longitudinal fasciculus. Major termination sites were found in the inferior oblique and superior rectus subdivisions of the oculomotor nucleus. Axonal branches then recrossed the midline and terminated in identical locations on the ipsilateral side. In the second case, cell bodies were located in the descending vestibular nucleus. Their axons crossed the midline and also ascended in the contralateral medial longitudinal fasciculus. Major termination sites were in the trochlear nucleus and in the inferior rectus subdivision of the oculomotor nucleus. As in the first case, axonal branches also recrossed the midline and terminated in identical motoneuron pools on the ipsilateral side. The above target sites were exactly those expected to be used in a reciprocal excitatory-inhibitory fashion during compensatory eye movements. Head-down movement would be excitatory for the lower horizontal canal producing contractions of both superior recti and inferior obliques as well as relaxation of the antagonistic inferior recti and superior obliques.(ABSTRACT TRUNCATED AT 400 WORDS)

Structure of the primate oculomotor burst generator. I. Medium-lead burst neurons with upward on-directions

1991 ◽  
Vol 65 (2) ◽  
pp. 203-217 ◽  
Author(s):  
A. K. Moschovakis ◽  
C. A. Scudder ◽  
S. M. Highstein
Keyword(s):  
Eye Movements ◽  
Mesencephalic Reticular Formation ◽  
Medial Longitudinal Fasciculus ◽  
Posterior Commissure ◽  
Inferior Rectus ◽  
Interstitial Nucleus Of Cajal ◽  
Burst Neurons ◽  
Physiological Characterization ◽  
Highly Correlated ◽  
Oculomotor Complex

1. To investigate the structure of the primate burst generator for vertical saccades, we obtained intra-axonal records from vertical medium-lead burst neurons with upward on-directions (UMLBs) in alert, behaving squirrel monkeys, while monitoring their spontaneous eye movements. After physiological characterization, these UMLBs were injected with horseradish peroxidase. 2. UMLBs (n = 14) had no spontaneous activity and emitted bursts of action potentials that preceded rapid eye movements by approximately 6 ms. Parameters of the burst (duration and number of spikes) were highly correlated with parameters of the rapid eye movement (duration and amplitude of the upward displacement of the eyes). 3. The axons of six UMLBs projected to the oculomotor complex. Their somata (4 were recovered) were all in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). Their axons traveled caudally in the medial longitudinal fasciculus (MLF) and ramified in the interstitial nucleus of Cajal (NIC) before entering the oculomotor nucleus. Five axons terminated bilaterally in the subdivisions innervating the superior rectus and inferior oblique muscles and therefore were presumed to be excitatory. One axon terminated in the ipsilateral inferior rectus and superior oblique subdivisions of the oculomotor complex and was presumed to be inhibitory. 4. Additionally, our data demonstrate that the nucleus of the posterior commissure (nPC) may also contain UMLBs. The axon of one such neuron crossed the midline within the posterior commissure and provided terminal fields to the contralateral nPC, riMLF, NIC, and the mesencephalic reticular formation but not to the oculomotor complex. 5. In conclusion, our data demonstrate that the rostral mesencephalon of the monkey contains neurons that have both the activity and the connections that are necessary either to provide motoneurons innervating extraocular muscles of both eyes with the pulse of activity they display during upward saccades or to inhibit their antagonists. Furthermore, our data demonstrate that some UMLBs are better suited for closing the feedback path of the local feedback loop rather than for providing direct input to extraocular motoneurons.

Reducing Contralateral SI Activity Reveals Hindlimb Receptive Fields in the SI Forelimb-Stump Representation of Neonatally Amputated Rats

2005 ◽  
Vol 94 (3) ◽  
pp. 1727-1732 ◽  
Author(s):  
Charles P. Pluto ◽  
Nicolas L. Chiaia ◽  
Robert W. Rhoades ◽  
Richard D. Lane
Keyword(s):  
Receptive Fields ◽  
Pyramidal Cells ◽  
Excitatory Input ◽  
Gabaergic Neurons ◽  
Projection Neurons ◽  
Excitatory Synapses ◽  
Adult Rats ◽  
Disynaptic Inhibition ◽  
Multiunit Recording ◽  
Monosynaptic Excitation

In adult rats that sustained forelimb amputation on the day of birth, >30% of multiunit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) also respond to cutaneous hindlimb stimulation when cortical GABAA+B receptors are blocked (GRB). This study examined whether hindlimb receptive fields could also be revealed in forelimb-stump sites by reducing one known source of excitatory input to SI GABAergic neurons, the contralateral SI cortex. Corpus callosum projection neurons connect homotopic SI regions, making excitatory contacts onto pyramidal cells and interneurons. Thus in addition to providing monosynaptic excitation in SI, callosal fibers can produce disynaptic inhibition through excitatory synapses with inhibitory interneurons. Based on the latter of these connections, we hypothesized that inactivating the contralateral (intact) SI forelimb region would “unmask” normally suppressed hindlimb responses by reducing the activity of SI GABAergic neurons. The SI forelimb-stump representation was first mapped under normal conditions and then during GRB to identify stump/hindlimb responsive sites. After GRB had dissipated, the contralateral (intact) SI forelimb region was mapped and reversibly inactivated with injections of 4% lidocaine, and selected forelimb-stump sites were retested. Contralateral SI inactivation revealed hindlimb responses in ∼60% of sites that were stump/hindlimb responsive during GRB. These findings indicate that activity in the contralateral SI contributes to the suppression of reorganized hindlimb receptive fields in neonatally amputated rats.

Neck Muscle Synergies During Stimulation and Inactivation of the Interstitial Nucleus of Cajal (INC)

2008 ◽  
Vol 100 (3) ◽  
pp. 1677-1685 ◽  
Author(s):  
Farshad Farshadmanesh ◽  
Pengfei Chang ◽  
Hongying Wang ◽  
Xiaogang Yan ◽  
Brian D. Corneil ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Head Rotation ◽  
Neck Muscles ◽  
Head Movements ◽  
Emg Activity ◽  
Muscle Synergies ◽  
Neck Muscle ◽  
Interstitial Nucleus Of Cajal ◽  
Splenius Capitis ◽  
The Relationship

The interstitial nucleus of Cajal (INC) is thought to control torsional and vertical head posture. Unilateral microstimulation of the INC evokes torsional head rotation to positions that are maintained until stimulation offset. Unilateral INC inactivation evokes head position-holding deficits with the head tilted in the opposite direction. However, the underlying muscle synergies for these opposite behavioral effects are unknown. Here, we examined neck muscle activity in head-unrestrained monkeys before and during stimulation (50 μA, 200 ms, 300 Hz) and inactivation (injection of 0.3 μl of 0.05% muscimol) of the same INC sites. Three-dimensional eye and head movements were recorded simultaneously with electromyographic (EMG) activity in six bilateral neck muscles: sternocleidomastoid (SCM), splenius capitis (SP), rectus capitis posterior major (RCPmaj.), occipital capitis inferior (OCI), complexus (COM), and biventer cervicis (BC). INC stimulation evoked a phasic, short-latency (∼5–10 ms) facilitation and later (∼100–200 ms) a more tonic facilitation in the activity of ipsi-SCM, ipsi-SP, ipsi-COM, ipsi-BC, contra-RCPmaj., and contra-OCI. Unilateral INC inactivation led to an increase in the activity of contra-SCM, ipsi-SP, ipsi-RCPmaj., and ipsi-OCI and a decrease in the activity of contra-RCPmaj. and contra-OCI. Thus the influence of INC stimulation and inactivation were opposite on some muscles (i.e., contra-OCI and contra-RCPmaj.), but the comparative influences on other neck muscles were more variable. These results show that the relationship between the neck muscle responses during INC stimulation and inactivation is much more complex than the relationship between the overt behaviors.

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