scholarly journals Neuronal thresholds and correlations in the peripheral vestibular system during rotation discrimination

2018 ◽  
Author(s):  
Courtney D. Garcia ◽  
Sheng Liu ◽  
Jean Laurens ◽  
Gregory C. DeAngelis ◽  
J. David Dickman ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Sensory Processing ◽  
Vestibular System ◽  
Vestibular Nuclei ◽  
Directional Selectivity ◽  
Related Activity ◽  
Significant Trial ◽  
Behavioral Thresholds ◽  
Semicircular Canal Afferents ◽  
Significant Pair

ABSTRACTNeuronal and behavioral thresholds were measured simultaneously as trained male macaques performed a yaw rotation discrimination task in darkness. When corrected to account for variations in neuronal direction preferences, neurons in the vestibular nuclei and semicircular canal afferents had discrimination thresholds that were only two-fold smaller than behavioral thresholds. There was no significant trial-by-trial correlation between neuronal activity and perceptual decisions, despite the presence of significant pair-wise noise correlations. The lack of choice-related activity during rotation discrimination contrasts with the robust correlations observed previously between brainstem neurons and choices during translation perception. These results suggest task-dependent differences in subcortical processing of vestibular signals, as well as how signals related to perceptual decisions may propagate back to early stages of sensory processing.SIGNIFICANCE STATEMENTThis is the first ever simultaneous recordings of neural and behavioral thresholds during rotation discrimination. Its importance lies on the fact that the vestibular system provides an excellent model to probe origins of perception because directional selectivity signals are similar at many levels of processing, from afferents to cortex. The findings of similar neuronal and behavioral discrimination thresholds, significant inter-neuronal correlations, but lack of correlations between behavior and neuronal activity of both afferents and central brainstem neurons are intriguing and suggest task-dependent organization of early sensory areas.

Convergent Properties of Vestibular-Related Brain Stem Neurons in the Gerbil

2000 ◽  
Vol 83 (4) ◽  
pp. 1958-1971 ◽  
Author(s):  
Galen D. Kaufman ◽  
Michael E. Shinder ◽  
Adrian A. Perachio
Keyword(s):  
Translational Motion ◽  
Stimulus Frequency ◽  
Head Rotation ◽  
Vestibular Nuclei ◽  
Inhibitory Input ◽  
Type I ◽  
Similar Response ◽  
Type Ii ◽  
Response Dynamics ◽  
Related Activity

Three classes of vestibular-related neurons were found in and near the prepositus and medial vestibular nuclei of alert or decerebrate gerbils, those responding to: horizontal translational motion, horizontal head rotation, or both. Their distribution ratios were 1:2:2, respectively. Many cells responsive to translational motion exhibited spatiotemporal characteristics with both response gain and phase varying as a function of the stimulus vector angle. Rotationally sensitive neurons were distributed as Type I, II, or III responses (sensitive to ipsilateral, contralateral, or both directions, respectively) in the ratios of 4:6:1. Four tested factors shaped the response dynamics of the sampled neurons: canal-otolith convergence, oculomotor-related activity, rotational Type (I or II), and the phase of the maximum response. Type I nonconvergent cells displayed increasing gains with increasing rotational stimulus frequency (0.1–2.0 Hz, 60°/s), whereas Type II neurons with convergent inputs had response gains that markedly decreased with increasing translational stimulus frequency (0.25–2.0 Hz, ±0.1 g). Type I convergent and Type II nonconvergent neurons exhibited essentially flat gains across the stimulus frequency range. Oculomotor-related activity was noted in 30% of the cells across all functional types, appearing as burst/pause discharge patterns related to the fast phase of nystagmus during head rotation. Oculomotor-related activity was correlated with enhanced dynamic range compared with the same category that had no oculomotor-related response. Finally, responses that were in-phase with head velocity during rotation exhibited greater gains with stimulus frequency increments than neurons with out-of-phase responses. In contrast, for translational motion, neurons out of phase with head acceleration exhibited low-pass characteristics, whereas in-phase neurons did not. Data from decerebrate preparations revealed that although similar response types could be detected, the sampled cells generally had lower background discharge rates, on average one-third lower response gains, and convergent properties that differed from those found in the alert animals. On the basis of the dynamic response of identified cell types, we propose a pair of models in which inhibitory input from vestibular-related neurons converges on oculomotor neurons with excitatory inputs from the vestibular nuclei. Simple signal convergence and combinations of different types of vestibular labyrinth information can enrich the dynamic characteristics of the rotational and translational vestibuloocular responses.

Primate premotor cortex: modulation of preparatory neuronal activity by gaze angle

1995 ◽  
Vol 73 (2) ◽  
pp. 886-890 ◽  
Author(s):  
D. Boussaoud
Keyword(s):  
Neuronal Activity ◽  
Premotor Cortex ◽  
Target Position ◽  
Delay Period ◽  
Coordinate Space ◽  
Eye Position ◽  
Related Activity ◽  
Visuomotor Task ◽  
Small Spot ◽  
The Right

1. This study investigated whether the neuronal activity of a cortical area devoted to the control of limb movements is affected by variations in eye position within the orbit. Two rhesus monkeys were trained to perform a conditional visuomotor task with an instructed delay period while maintaining gaze on a fixation point. 2. The experimental design required each monkey to put its hand on a metal touch pad located at arm's length and fixate a small spot of light presented on a computer screen. Then a visual cue came on, at the fixation point or elsewhere, the color of which instructed the monkey to move its limb to one of two touch pads according to a conditional rule. A red cue meant a movement to the left, whereas a green one instructed a movement to the right. The cue lasted for a variable delay period (1-3 s), and the monkey had to wait for its offset, the go signal, before performing the correct response. The fixation point and the cues were presented at various screen locations in a combination that allowed examination of whether eye position and/or target position modulate the neuronal activity. Because the monkeys' heads were fixed, all changes in eye position reflected movements in a craniocentric, head-centered, coordinate space. 3. The activity of single neurons was recorded from dorsal premotor cortex (PMd). For most neurons (79%), the activity during the instructed delay period (set-related activity) reflects the direction of the upcoming limb movement but varies significantly with eye position.(ABSTRACT TRUNCATED AT 250 WORDS)

Laterality of Movement-Related Activity Reflects Transformation of Coordinates in Ventral Premotor Cortex and Primary Motor Cortex of Monkeys

2007 ◽  
Vol 98 (4) ◽  
pp. 2008-2021 ◽  
Author(s):  
Kiyoshi Kurata
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Visuomotor Transformation ◽  
Related Activity ◽  
Reaching Task ◽  
Ventral Premotor Cortex ◽  
Cortical Motor ◽  
Target Locations

The ventral premotor cortex (PMv) and the primary motor cortex (MI) of monkeys participate in various sensorimotor integrations, such as the transformation of coordinates from visual to motor space, because the areas contain movement-related neuronal activity reflecting either visual or motor space. In addition to relationship to visual and motor space, laterality of the activity could indicate stages in the visuomotor transformation. Thus we examined laterality and relationship to visual and motor space of movement-related neuronal activity in the PMv and MI of monkeys performing a fast-reaching task with the left or right arm, toward targets with visual and motor coordinates that had been dissociated by shift prisms. We determined laterality of each activity quantitatively and classified it into four types: activity that consistently depended on target locations in either head-centered visual coordinates (V-type) or motor coordinates (M-type) and those that had either differential or nondifferential activity for both coordinates (B- and N-types). A majority of M-type neurons in the areas had preferences for reaching movements with the arm contralateral to the hemisphere where neuronal activity was recorded. In contrast, most of the V-type neurons were recorded in the PMv and exhibited less laterality than the M-type. The B- and N-types were recorded in the PMv and MI and exhibited intermediate properties between the V- and M-types when laterality and correlations to visual and motor space of them were jointly examined. These results suggest that the cortical motor areas contribute to the transformation of coordinates to generate final motor commands.

Developmental Dyspraxia: Is it a Unitary Function?

1987 ◽  
Vol 7 (2) ◽  
pp. 93-110 ◽  
Author(s):  
A. Jean Ayres ◽  
Zoe K. Mailloux ◽  
Cathy L. W. Wendler
Keyword(s):  
Visual Perception ◽  
Sensory Processing ◽  
Vestibular System ◽  
Concept Formation ◽  
Auditory Memory ◽  
Factor Analyses ◽  
Clinical Observations ◽  
Different Types ◽  
Developmental Dyspraxia

Children ( N = 182) with known or suspected sensory integrative dysfunction and who ranged in age front 4 years, 0 months, to 9 years, 11 months, were assessed using tests and clinical observations to examine developmental dyspraxia. Correlations and factor analyses indicated strong associations between praxis, tactile sensory processing, visual perception, and repeating of sentences. The major factor represented visuosomatopraxis function with elements linked by concept formation. Auditory memory delineated a second factor and kinesthesia another factor. Any contribution of the vestibular system to praxis could not be clearly isolated. The study did not justify the existence of either a unitary function or different types of developmental dyspraxia; rather, it supported the idea of a general praxis function and of additional differentiated practic skills defined by behavioral goals.

scholarly journals Neuronal activity in the premotor cortex of monkeys reflects both cue salience and motivation for action generation and inhibition

2019 ◽  
Author(s):  
Margherita Giamundo ◽  
Franco Giarrocco ◽  
Emiliano Brunamonti ◽  
Francesco Fabbrini ◽  
Pierpaolo Pani ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Premotor Cortex ◽  
Motor Program ◽  
Behavioural Response ◽  
Stop Signal Task ◽  
Related Activity ◽  
Reward Circuitry ◽  
Behavioural Performance ◽  
Cue Salience

ABSTRACTAnimals adopt different strategies, promoting certain actions and withholding inconvenient ones, to achieve their goals. The motivation to obtain them is the main drive that determines the behavioural performance. While much work has focused on understanding how motor cortices control actions, their role on motivated behaviours remains unclear. We recorded from dorsal premotor cortex (PMd) of monkeys performing a modified version of the stop-signal task, in which the motivation to perform/withhold an action was manipulated by presenting cues that informed on the probability to obtain different amounts of reward in relation to the motor outcome. According to the motivational context, animals performance adapted to maximize reward. Neuronal activity displayed a cue salience related modulation at trial start and, while the behavioural response approached, reflected more the motivation to start/cancel the action. These findings reveal multiple representations of motivation-related signals in PMd, highlighting its involvement in the control of finalized actions.SIGNIFICATIVE STATEMENTThe motivation to obtain rewards drives how animals act over their environment. To explore the involvement of motor cortices in motivated behaviours, we recorded high-resolution neuronal activity in the premotor cortex of monkeys performing a task that manipulated the motivation to generate/withhold a movement through different cued reward probabilities. Our results show the presence of neuronal signals dynamically reflecting a cue related activity, in the time immediately following its presentation, and a motivation related activity in performing (or cancelling) a motor program, while the behavioural response approached. The encoding of multiple reward-related signals in motor regions, leads to consider an important role of premotor areas in the reward circuitry.

scholarly journals Cortical activity at different time scales: high-pass filtering separates motor planning and execution

2019 ◽  
Author(s):  
David Eriksson ◽  
Mona Heiland ◽  
Artur Schneider ◽  
Ilka Diester
Keyword(s):  
Neuronal Activity ◽  
Motor Planning ◽  
Population Level ◽  
Motor Execution ◽  
Related Activity ◽  
Pass Filter ◽  
Planning Processes ◽  
Filter Approach ◽  
High Pass ◽  
Forelimb Movements

AbstractThe smooth conduction of movements requires simultaneous motor planning and execution according to internal goals. So far it is not known how such movement plans can be modified without being distorted by ongoing movements. Previous studies have isolated planning and execution related neuronal activity by separating behavioral planning and movement periods in time by sensory cues1–7. Here, we introduced two novel tasks in which motor planning developed intrinsically. We separated this continuous self-paced motor planning statistically from motor execution by experimentally minimizing the repetitiveness of the movements. Thereby, we found that in the rat sensorimotor cortex, neuronal motor planning processes evolved with slower dynamics than movement related responses both on a sorted unit and population level. The fast evolving neuronal activity preceded skilled forelimb movements while it coincided with movements in a locomotor task. We captured this fast evolving movement related activity via a high-pass filter approach and confirmed the results with optogenetic stimulations. As biological mechanism underlying such a high pass filtering we suggest neuronal adaption. The differences in dynamics combined with a high pass filtering mechanism represents a simple principle for concurrent motor planning and execution in which planning will result in relatively slow dynamics that will not produce movements.

Premotor cortex of monkeys: set- and movement-related activity reflecting amplitude and direction of wrist movements

1993 ◽  
Vol 69 (1) ◽  
pp. 187-200 ◽  
Author(s):  
K. Kurata
Keyword(s):  
Neuronal Activity ◽  
Premotor Cortex ◽  
Delay Period ◽  
Visual Signal ◽  
Activity Change ◽  
Related Activity ◽  
Sustained Activity ◽  
Parallel Processes ◽  
Dorsal Aspect ◽  
Period 2

1. Neuronal activity was recorded from the premotor cortex (PM) of Japanese monkeys while they performed hand movements with different amplitudes and directions. On each behavioral trial, two instructions were given sequentially: 1) an amplitude instruction (large or small) and 2) a direction instruction (flexion or extension). The onset of movement was triggered by a visual signal after a delay period. 2. Among various kinds of task-related neuronal activity recorded in the PM, two types were selected for study: 1) set-related activity, sustained activity change during the delay period that followed presentation of instruction signals (IS); and 2) movement-related activity, activity change immediately before and during movement, which followed the trigger signal (TS) presentation. 3. Thirty-two of 101 set-related neurons showed activity change after presentation of the first IS (Delay 1 set-related activity), when they were instructed in either amplitude or direction, but not both. All of the set-related neurons showed activity modulation after presentation of the second IS (Delay 2 set-related activity). When neurons showed both Delay 1 and Delay 2 set-related activity, they were usually more active during Delay 2, i.e., when the monkeys had received both amplitude and directional ISs. A majority of neurons with Delay 2 set-related activity (64%) showed relation to both movement amplitude and direction. Twenty-eight percent of the neurons showed relation to either amplitude or direction, but not both. These findings seem consistent with a view that serial, rather than parallel, processes of motor programming operate in preparation of intended movements. 4. A majority of PM neurons with movement-related activity (51%) showed activity change related to both the direction and amplitude of movement. Forty-two percent showed selective relation to either direction or amplitude. These findings support a view that PM contributes to the control of limb movements. 5. Histological reconstruction showed that a vast majority of PM set-related neurons were located in the dorsal aspect of the PM (PMd), medial to the arcuate spur and lateral to the superior precentral sulcus. In contrast, movement-related neurons were distributed in two distinct foci: one in the ventral aspect of the PM (PMv), immediately caudal to the genu of the arcuate sulcus and lateral to the spur of the sulcus; and the other in the PMd, overlap;ing the location of set-related neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

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