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Smooth pursuit-related information processing in frontal eye field neurons that project to the NRTP.

Ono S, Mustari MJ - Cereb. Cortex (2008)

Bottom Line: In contrast, FEF neurons not activated following ES of rNRTP were often most sensitive to eye velocity.In similar modeling studies, we found that rNRTP neurons were also biased toward eye acceleration.Therefore, our results suggest that neurons in the FEF-rNRTP pathway carry signals that could play a primary role in initiation of SP.

View Article: PubMed Central - PubMed

Affiliation: Division of Sensory-Motor Systems, Yerkes National Primate Research Center, and Department of Neurology, Emory University, 954 Gatewood Road Northeast, Atlanta, GA 30329, USA.

ABSTRACT
The cortical pursuit system begins the process of transforming visual signals into commands for smooth pursuit (SP) eye movements. The frontal eye field (FEF), located in the fundus of arcuate sulcus, is known to play a role in SP and gaze pursuit movements. This role is supported, at least in part, by FEF projections to the rostral nucleus reticularis tegmenti pontis (rNRTP), which in turn projects heavily to the cerebellar vermis. However, the functional characteristics of SP-related FEF neurons that project to rNRTP have never been described. Therefore, we used microelectrical stimulation (ES) to deliver single pulses (50-200 microA, 200-micros duration) in rNRTP to antidromically activate FEF neurons. We estimated the eye or retinal error motion sensitivity (position, velocity, and acceleration) of FEF neurons during SP using multiple linear regression modeling. FEF neurons that projected to rNRTP were most sensitive to eye acceleration. In contrast, FEF neurons not activated following ES of rNRTP were often most sensitive to eye velocity. In similar modeling studies, we found that rNRTP neurons were also biased toward eye acceleration. Therefore, our results suggest that neurons in the FEF-rNRTP pathway carry signals that could play a primary role in initiation of SP.

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Comparison of partial r2 values between eye (A, left panel) and retinal error (A, right panel) position, velocity, and acceleration parameters for each FEF neuron antidromically activated (red symbols) or not activated (blue symbols) following electrical stimulation of rNRTP. (B) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) for neurons antidromically activated from rNRTP. Eye acceleration parameters show larger partial r2 values than eye position and velocity parameters, indicating the relative importance of eye acceleration. Retinal error motion parameters show relatively smaller contributions than eye motion parameters. (C) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) in neurons not activated following electrical stimulation of rNRTP. Eye velocity parameter shows larger partial r2 values than eye position and acceleration parameters, indicating the relative importance of eye velocity.
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fig6: Comparison of partial r2 values between eye (A, left panel) and retinal error (A, right panel) position, velocity, and acceleration parameters for each FEF neuron antidromically activated (red symbols) or not activated (blue symbols) following electrical stimulation of rNRTP. (B) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) for neurons antidromically activated from rNRTP. Eye acceleration parameters show larger partial r2 values than eye position and velocity parameters, indicating the relative importance of eye acceleration. Retinal error motion parameters show relatively smaller contributions than eye motion parameters. (C) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) in neurons not activated following electrical stimulation of rNRTP. Eye velocity parameter shows larger partial r2 values than eye position and acceleration parameters, indicating the relative importance of eye velocity.

Mentions: The 6-component model provided a good fit to all the experimentally derived data in FEF (CD = 0.75 ± 0.15, n = 45). We determined the distribution of partial r2 values for eye and retinal error position, velocity, and acceleration to show the differential sensitivity of each FEF neuron (antidromically activated or not activated) to each motion component. These partial r2 are plotted in Figure 6A. The majority of FEF neurons antidromically activated following rNRTP stimulation have the largest contributions from eye acceleration compared with eye position, velocity, or retinal error motion during step-ramp tracking (Fig. 6A, red circles). In contrast, we found that FEF neurons not activated have a distribution of partial r2 values indicating larger contributions from eye velocity rather than acceleration during step-ramp tracking (Fig. 6A, blue circles). Median partial r2 values for antidromically activated neurons are higher for eye acceleration (0.21, n = 20) than eye velocity (0.06, n = 20), eye position (0.04, n = 20), or retinal error components (P < 0.001, 1-way analysis of variance (ANOVA) on ranks; Fig. 6B). In contrast, median partial r2 values for neurons not activated indicate that eye velocity (0.18, n = 25) makes a larger contribution than eye position (0.06, n = 25), acceleration (0.05, n = 25), or retinal error components (P < 0.001, 1-way ANOVA on ranks; Fig. 6C).


Smooth pursuit-related information processing in frontal eye field neurons that project to the NRTP.

Ono S, Mustari MJ - Cereb. Cortex (2008)

Comparison of partial r2 values between eye (A, left panel) and retinal error (A, right panel) position, velocity, and acceleration parameters for each FEF neuron antidromically activated (red symbols) or not activated (blue symbols) following electrical stimulation of rNRTP. (B) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) for neurons antidromically activated from rNRTP. Eye acceleration parameters show larger partial r2 values than eye position and velocity parameters, indicating the relative importance of eye acceleration. Retinal error motion parameters show relatively smaller contributions than eye motion parameters. (C) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) in neurons not activated following electrical stimulation of rNRTP. Eye velocity parameter shows larger partial r2 values than eye position and acceleration parameters, indicating the relative importance of eye velocity.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig6: Comparison of partial r2 values between eye (A, left panel) and retinal error (A, right panel) position, velocity, and acceleration parameters for each FEF neuron antidromically activated (red symbols) or not activated (blue symbols) following electrical stimulation of rNRTP. (B) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) for neurons antidromically activated from rNRTP. Eye acceleration parameters show larger partial r2 values than eye position and velocity parameters, indicating the relative importance of eye acceleration. Retinal error motion parameters show relatively smaller contributions than eye motion parameters. (C) Median partial r2 values of eye motion (left panel) and retinal error motion parameters (right panel) in neurons not activated following electrical stimulation of rNRTP. Eye velocity parameter shows larger partial r2 values than eye position and acceleration parameters, indicating the relative importance of eye velocity.
Mentions: The 6-component model provided a good fit to all the experimentally derived data in FEF (CD = 0.75 ± 0.15, n = 45). We determined the distribution of partial r2 values for eye and retinal error position, velocity, and acceleration to show the differential sensitivity of each FEF neuron (antidromically activated or not activated) to each motion component. These partial r2 are plotted in Figure 6A. The majority of FEF neurons antidromically activated following rNRTP stimulation have the largest contributions from eye acceleration compared with eye position, velocity, or retinal error motion during step-ramp tracking (Fig. 6A, red circles). In contrast, we found that FEF neurons not activated have a distribution of partial r2 values indicating larger contributions from eye velocity rather than acceleration during step-ramp tracking (Fig. 6A, blue circles). Median partial r2 values for antidromically activated neurons are higher for eye acceleration (0.21, n = 20) than eye velocity (0.06, n = 20), eye position (0.04, n = 20), or retinal error components (P < 0.001, 1-way analysis of variance (ANOVA) on ranks; Fig. 6B). In contrast, median partial r2 values for neurons not activated indicate that eye velocity (0.18, n = 25) makes a larger contribution than eye position (0.06, n = 25), acceleration (0.05, n = 25), or retinal error components (P < 0.001, 1-way ANOVA on ranks; Fig. 6C).

Bottom Line: In contrast, FEF neurons not activated following ES of rNRTP were often most sensitive to eye velocity.In similar modeling studies, we found that rNRTP neurons were also biased toward eye acceleration.Therefore, our results suggest that neurons in the FEF-rNRTP pathway carry signals that could play a primary role in initiation of SP.

View Article: PubMed Central - PubMed

Affiliation: Division of Sensory-Motor Systems, Yerkes National Primate Research Center, and Department of Neurology, Emory University, 954 Gatewood Road Northeast, Atlanta, GA 30329, USA.

ABSTRACT
The cortical pursuit system begins the process of transforming visual signals into commands for smooth pursuit (SP) eye movements. The frontal eye field (FEF), located in the fundus of arcuate sulcus, is known to play a role in SP and gaze pursuit movements. This role is supported, at least in part, by FEF projections to the rostral nucleus reticularis tegmenti pontis (rNRTP), which in turn projects heavily to the cerebellar vermis. However, the functional characteristics of SP-related FEF neurons that project to rNRTP have never been described. Therefore, we used microelectrical stimulation (ES) to deliver single pulses (50-200 microA, 200-micros duration) in rNRTP to antidromically activate FEF neurons. We estimated the eye or retinal error motion sensitivity (position, velocity, and acceleration) of FEF neurons during SP using multiple linear regression modeling. FEF neurons that projected to rNRTP were most sensitive to eye acceleration. In contrast, FEF neurons not activated following ES of rNRTP were often most sensitive to eye velocity. In similar modeling studies, we found that rNRTP neurons were also biased toward eye acceleration. Therefore, our results suggest that neurons in the FEF-rNRTP pathway carry signals that could play a primary role in initiation of SP.

Show MeSH
Related in: MedlinePlus