Differential Temporal Storage Capacity in the Baseline Activity of Neurons in Macaque Frontal Eye Field and Area V4

2010 ◽  
Vol 103 (5) ◽  
pp. 2433-2445 ◽  
Author(s):  
Tadashi Ogawa ◽  
Hidehiko Komatsu
Keyword(s):  
Neuronal Activity ◽  
Storage Capacity ◽  
Discharge Rate ◽  
Time Lag ◽  
Temporal Correlation ◽  
Frontal Eye Field ◽  
Area V4 ◽  
Baseline Activity ◽  
Eye Field ◽  
V4 Neurons

Previous studies have suggested that spontaneous fluctuations in neuronal activity reflect intrinsic functional brain architecture. Inspired by these findings, we analyzed baseline neuronal activity in the monkey frontal eye field (FEF; a visuomotor area) and area V4 (a visual area) during the fixation period of a cognitive behavioral task in the absence of any task-specific stimuli or behaviors. Specifically, we examined the temporal storage capacity of the instantaneous discharge rate in FEF and V4 neurons by calculating the correlation of the spike count in a bin with that in another bin during the baseline activity of a trial. We found that most FEF neurons fired significantly more (or less) in one bin if they fired more (or less) in another bin within a trial, even when these two time bins were separated by hundreds of milliseconds. By contrast, similar long time-lag correlations were observed in only a small fraction of V4 neurons, indicating that temporal correlations were considerably stronger in FEF compared with those in V4 neurons. Additional analyses revealed that the findings were not attributable to other task-related variables or ongoing behavioral performance, suggesting that the differences in temporal correlation strength reflect differences in intrinsic structural and functional architecture between visual and visuomotor areas. Thus FEF neurons probably play a greater role than V4 neurons in neural circuits responsible for temporal storage in activity.

Visually guided saccade versus eye-hand reach: contrasting neuronal activity in the cortical supplementary and frontal eye fields

1996 ◽  
Vol 75 (5) ◽  
pp. 2187-2191 ◽  
Author(s):  
H. Mushiake ◽  
N. Fujii ◽  
J. Tanji
Keyword(s):  
Eye Movement ◽  
Neuronal Activity ◽  
Motor Task ◽  
Oculomotor Control ◽  
Frontal Eye Field ◽  
Frontal Eye Fields ◽  
Saccadic Eye Movement ◽  
Visually Guided ◽  
Supplementary Eye Field ◽  
Eye Field

1. We studied neuronal activity in the supplementary eye field (SEF) and frontal eye field (FEF) of a monkey during performance of a conditional motor task that required capturing of a target either with a saccadic eye movement (the saccade-only condition) or with an eye-hand reach (the saccade-and-reach condition), according to visual instructions. 2. Among 106 SEF neurons that showed presaccadic activity, more than one-half of them (54%) were active preferentially under the saccade-only condition (n = 12) or under the saccade-and-reach condition (n = 45), while the remaining 49 neurons were equally active in both conditions. 3. By contrast, most (97%) of the 109 neurons in the FEF exhibited approximately equal activity in relation to saccades under the two conditions. 4. The present results suggest the possibility that SEF neurons, at least in part, are involved in signaling whether the motor task is oculomotor or combined eye-arm movements, whereas FEF neurons are mostly related to oculomotor control.

scholarly journals Role of Supplementary Eye Field in Saccade Initiation: Executive, Not Direct, Control

2010 ◽  
Vol 103 (2) ◽  
pp. 801-816 ◽  
Author(s):  
Veit Stuphorn ◽  
Joshua W. Brown ◽  
Jeffrey D. Schall
Keyword(s):  
Discharge Rate ◽  
Stop Signal ◽  
Stop Signal Task ◽  
Frontal Eye Field ◽  
Signal Trial ◽  
Visually Guided ◽  
Supplementary Eye Field ◽  
Task Requirements ◽  
Gaze Holding ◽  
Eye Field

The goal of this study was to determine whether the activity of neurons in the supplementary eye field (SEF) is sufficient to control saccade initiation in macaque monkeys performing a saccade countermanding (stop signal) task. As previously observed, many neurons in the SEF increase the discharge rate before saccade initiation. However, when saccades are canceled in response to a stop signal, effectively no neurons with presaccadic activity display discharge rate modulation early enough to contribute to saccade cancellation. Moreover, SEF neurons do not exhibit a specific threshold discharge rate that could trigger saccade initiation. Yet, we observed more subtle relations between SEF activation and saccade production. The activity of numerous SEF neurons was correlated with response time and varied with sequential adjustments in response latency. Trials in which monkeys canceled or produced a saccade in a stop signal trial were distinguished by a modest difference in discharge rate of these SEF neurons before stop signal or target presentation. These findings indicate that neurons in the SEF, in contrast to counterparts in the frontal eye field and superior colliculus, do not contribute directly and immediately to the initiation of visually guided saccades. However the SEF may proactively regulate saccade production by biasing the balance between gaze-holding and gaze-shifting based on prior performance and anticipated task requirements.

scholarly journals Feature-Based Attention in the Frontal Eye Field and Area V4 during Visual Search

Neuron ◽  
2011 ◽  
Vol 70 (6) ◽  
pp. 1205-1217 ◽  
Author(s):  
Huihui Zhou ◽  
Robert Desimone
Keyword(s):  
Visual Search ◽  
Frontal Eye Field ◽  
Area V4 ◽  
Eye Field ◽  
Feature Based

scholarly journals Motor selection dynamics in FEF explain the reaction time variance of saccades to single targets

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Christopher K Hauser ◽  
Dantong Zhu ◽  
Terrence R Stanford ◽  
Emilio Salinas
Keyword(s):  
Reaction Time ◽  
Single Neuron ◽  
Frontal Eye Field ◽  
Initial State ◽  
Baseline Activity ◽  
Selection Dynamics ◽  
Computational Work ◽  
Eye Field ◽  
Threshold Process ◽  
Oculomotor Activity

In studies of voluntary movement, a most elemental quantity is the reaction time (RT) between the onset of a visual stimulus and a saccade toward it. However, this RT demonstrates extremely high variability which, in spite of extensive research, remains unexplained. It is well established that, when a visual target appears, oculomotor activity gradually builds up until a critical level is reached, at which point a saccade is triggered. Here, based on computational work and single-neuron recordings from monkey frontal eye field (FEF), we show that this rise-to-threshold process starts from a dynamic initial state that already contains other incipient, internally driven motor plans, which compete with the target-driven activity to varying degrees. The ensuing conflict resolution process, which manifests in subtle covariations between baseline activity, build-up rate, and threshold, consists of fundamentally deterministic interactions, and explains the observed RT distributions while invoking only a small amount of intrinsic randomness.

Estimating invisible target speed from neuronal activity in monkey frontal eye field

10.1038/nn990 ◽  
2002 ◽  
Vol 6 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Andrei Barborica ◽  
Vincent P. Ferrera
Keyword(s):  
Neuronal Activity ◽  
Frontal Eye Field ◽  
Target Speed ◽  
Eye Field

Threshold mechanism for saccade initiation in frontal eye field and superior colliculus

2013 ◽  
Vol 109 (11) ◽  
pp. 2767-2780 ◽  
Author(s):  
Jay J. Jantz ◽  
Masayuki Watanabe ◽  
Stefan Everling ◽  
Douglas P. Munoz
Keyword(s):  
Superior Colliculus ◽  
Discharge Rate ◽  
Population Level ◽  
Threshold Level ◽  
Frontal Eye Field ◽  
Visual Responses ◽  
Variable Threshold ◽  
Discharge Rates ◽  
Fixed Threshold ◽  
Eye Field

In an influential model of frontal eye field (FEF) and superior colliculus (SC) activity, saccade initiation occurs when the discharge rate of either single neurons or a population of neurons encoding a saccade motor plan reaches a threshold level of activity. Conflicting evidence exists for whether this threshold is fixed or can change under different conditions. We tested the fixed-threshold hypothesis at the single-neuron and population levels to help resolve the inconsistency between previous studies. Two rhesus monkeys performed a randomly interleaved pro- and antisaccade task in which they had to look either toward (pro) or 180° away (anti) from a peripheral visual stimulus. We isolated visuomotor (VM) and motor (M) neurons in the FEF and SC and tested three specific predictions of a fixed-threshold hypothesis. We found little support for fixed thresholds. First, correlations were never totally absent between presaccadic discharge rate and saccadic reaction time when examining a larger (plausible) temporal period. Second, presaccadic discharge rates varied markedly between saccade tasks. Third, visual responses exceeded presaccadic motor discharges for FEF and SC VM neurons. We calculated that only a remarkably strong bias for M neurons in downstream projections could render the fixed-threshold hypothesis plausible at the population level. Also, comparisons of gap vs. overlap conditions indicate that increased inhibitory tone may be associated with stability of thresholds. We propose that fixed thresholds are the exception rather than the rule in FEF and SC, and that stabilization of an otherwise variable threshold depends on task-related, inhibitory modulation.

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