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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 neuronal response dynamics for representative FEF (conventions as in Figure 3) and rNRTP (Ono et al. 2005) SP neurons during step-ramp tracking. Response of antidromically activated FEF SP neuron (A) and rNRTP SP neuron (B). Both neurons show a strong transient responses during SP initiation. (C) Partial r2values for SP neurons in the rNRTP (Ono et al. 2005) and in FEF (antidromically activated from rNRTP). Both populations show considerable overlap with a trend toward most sensitivity to eye acceleration.
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fig8: Comparison of neuronal response dynamics for representative FEF (conventions as in Figure 3) and rNRTP (Ono et al. 2005) SP neurons during step-ramp tracking. Response of antidromically activated FEF SP neuron (A) and rNRTP SP neuron (B). Both neurons show a strong transient responses during SP initiation. (C) Partial r2values for SP neurons in the rNRTP (Ono et al. 2005) and in FEF (antidromically activated from rNRTP). Both populations show considerable overlap with a trend toward most sensitivity to eye acceleration.

Mentions: In a previous study (Ono et al. 2005), we showed that SP-related neurons in rNRTP were most sensitive to eye acceleration. In Figure 8, we show examples of FEF (Fig. 8A) and rNRTP (Fig. 8B) neurons during step-ramp tracking and their partial r2 values obtained in our modeling studies (Fig. 8C). Although the population of antidromically activated FEF and rNRTP neurons is small, there is considerable overlap in the distributions with respect to eye motion parameters. Eye acceleration provides the largest contribution to FEF and rNRTP SP activity during step-ramp tracking.


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

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

Comparison of neuronal response dynamics for representative FEF (conventions as in Figure 3) and rNRTP (Ono et al. 2005) SP neurons during step-ramp tracking. Response of antidromically activated FEF SP neuron (A) and rNRTP SP neuron (B). Both neurons show a strong transient responses during SP initiation. (C) Partial r2values for SP neurons in the rNRTP (Ono et al. 2005) and in FEF (antidromically activated from rNRTP). Both populations show considerable overlap with a trend toward most sensitivity to eye acceleration.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2665162&req=5

fig8: Comparison of neuronal response dynamics for representative FEF (conventions as in Figure 3) and rNRTP (Ono et al. 2005) SP neurons during step-ramp tracking. Response of antidromically activated FEF SP neuron (A) and rNRTP SP neuron (B). Both neurons show a strong transient responses during SP initiation. (C) Partial r2values for SP neurons in the rNRTP (Ono et al. 2005) and in FEF (antidromically activated from rNRTP). Both populations show considerable overlap with a trend toward most sensitivity to eye acceleration.
Mentions: In a previous study (Ono et al. 2005), we showed that SP-related neurons in rNRTP were most sensitive to eye acceleration. In Figure 8, we show examples of FEF (Fig. 8A) and rNRTP (Fig. 8B) neurons during step-ramp tracking and their partial r2 values obtained in our modeling studies (Fig. 8C). Although the population of antidromically activated FEF and rNRTP neurons is small, there is considerable overlap in the distributions with respect to eye motion parameters. Eye acceleration provides the largest contribution to FEF and rNRTP SP activity during step-ramp tracking.

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