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Frontal eye fields

The frontal eye fields (FEF) are a region of the primate frontal cortex located in the posterior middle frontal gyrus, primarily encompassing Brodmann areas 6 and 8 along the superior precentral sulcus near its junction with the superior frontal sulcus, serving as a key node for initiating voluntary saccadic eye movements and directing visuospatial attention.^[1]^[2] First identified through electrical stimulation studies in the late 19th century, the FEF generate command signals that compute the direction and amplitude of saccades, projecting via pathways such as the corticotectal tract to influence subcortical structures like the superior colliculus for coordinated gaze shifts.^[3]^[1] Beyond basic oculomotor control, the FEF integrate sensory information to support higher cognitive functions, including spatial working memory, saliency detection, and the coupling of attention with eye movements in both overt and covert tasks.^[2]^[3] Neurons within the FEF exhibit topographic organization, representing contralateral visual space and modulating activity in downstream visual cortical areas such as V1 through V4.^[2] As part of the broader dorsal attention network, the FEF connect structurally via the superior longitudinal fasciculus to parietal regions like the intraparietal sulcus, enabling flexible shifts in focus essential for visual exploration and decision-making.^[2] Disruptions to the FEF, often studied through techniques like transcranial magnetic stimulation, impair saccade accuracy and attentional orienting, underscoring their role in everyday visuomotor behaviors.^[3]

Anatomy

Location and boundaries

The frontal eye fields (FEF) primarily correspond to Brodmann areas 6 and 8 (BA6 and BA8) in humans, occupying the posterior portion of the superior frontal gyrus and extending into the anterior portion of the middle frontal gyrus.^[4]^[2] This region is situated at the intersection of the precentral sulcus and the superior frontal sulcus, marking its core anatomical position in the prefrontal cortex.^[5] The FEF lies at the junction of the premotor cortex (BA6) and Brodmann area 8, with the precentral sulcus forming its primary posterior boundary and more rostral prefrontal regions defining its anterior extent.^[4] Medially, it borders the supplementary motor area along the superior frontal gyrus.^[6] In standard brain atlases, the FEF is localized using Talairach or MNI coordinates, with approximate centers ranging from x = -41 to +37 mm, y = -18 to +26 mm, and z = 29 to 49 mm across hemispheres, reflecting variability from neuroimaging studies.^[3] These coordinates highlight the bilateral symmetry of the FEF, often centered near x = ±32 mm, y = -2 mm, z = 46 mm in Talairach space.^[3] Comparatively, in non-human primates such as macaques, the FEF is located on the anterior bank of the arcuate sulcus, encompassing parts of areas 8A and 45 within the rostral frontal lobe.^[7] This positioning aligns closely with human anatomy but is more consistently sulcal in monkeys. In rodents like rats, the FEF homolog—termed the frontal orienting fields (FOF)—is more diffusely distributed across the frontal cortex, particularly in the prelimbic and anterior cingulate regions, lacking a distinct sulcal landmark.^[8] The FEF exhibits evolutionary conservation across mammals, serving as a key hub for visuomotor control and orienting behaviors from prosimians to primates and rodents, with homologous regions identified through microstimulation and connectivity patterns that support gaze shifts.^[9]

Cytoarchitecture and organization

The cytoarchitecture of the frontal eye fields (FEF) is characterized by features typical of agranular or dysgranular frontal cortex, as identified through histological techniques such as Nissl staining. These methods reveal a layered structure with reduced prominence of the granular layer IV compared to sensory areas like the visual cortex, where layer IV is densely packed with small granule cells. In the FEF, layer IV appears thin, discontinuous, or absent in certain subdivisions, contributing to its classification as dysgranular in primates.^[10]^[11] Layer-specific organization emphasizes a predominance of pyramidal neurons in supragranular layers II/III and infragranular layer V, which form the bulk of excitatory output pathways. Layer V, in particular, contains a high concentration of large pyramidal cells with diameters exceeding 22 μm, outnumbering those in layer III and exhibiting a diffuse distribution. In contrast, layers II/III feature medium-sized pyramids, while infragranular layers V and VI show a elevated ratio (approximately 1.35) of neurofilament protein-immunoreactive neurons relative to supragranular layers. This laminar pattern supports the FEF's role in integrating motor commands, with minimal emphasis on primary sensory processing evident in the subdued granularity.^[10]^[11] The primary neuronal population consists of large excitatory pyramidal cells, which dominate output functions through their projections from deeper layers. These cells vary in size, with the largest concentrated in layer V for long-range signaling. Inhibitory interneurons, including parvalbumin-positive (PV+) types, provide local modulation; PV+ cells are uniformly distributed across deeper layers (III–VI) with densities around 3,600 cells per mm³ and cell body sizes ranging from 4–25 μm, helping to sharpen neural responses and maintain circuit balance. Other interneurons, such as those expressing calbindin or calretinin, are more prevalent in superficial layers but play supportive roles in modulating excitability.^[11]^[12]^[12] Internal organization includes potential anterior-posterior gradients in neuron density and pyramidal cell size, with posterior regions of the FEF displaying higher concentrations of large layer V pyramids associated with saccade execution. Recent cytoarchitectonic mapping (as of 2025) distinguishes subdivisions within the premotor cortex, such as area 6v1 corresponding to the core FEF and 6v2 to an inferior variant, each with variations in layer IIIc pyramidal size and columnar arrangements for refined spatial processing.^[11]^[6] These gradients align with functional transitions from planning in anterior zones to more direct motor involvement posteriorly.

Neural connections

Afferent inputs

The frontal eye fields (FEF) receive a variety of afferent inputs that integrate sensory information and cognitive signals to support eye movement control. Visual inputs primarily originate from extrastriate cortical areas, including V2, V4, and the middle temporal area (MT/V5), providing processed spatial and motion-related information through direct corticocortical projections. These pathways terminate in layer IV of the FEF, facilitating hierarchical sensory processing. Parietal inputs to the FEF arise mainly from the lateral intraparietal area (LIP), forming reciprocal connections that convey spatial attention and saccade-related signals via direct corticocortical routes. These projections, identified in tracer studies in nonhuman primates, target multiple layers of the FEF and support coordinated visuospatial processing. Auditory and multisensory afferents reach the FEF from the superior temporal sulcus (STS) and auditory cortex, enabling integration of non-visual cues for rapid orienting responses. These inputs elicit ultra-rapid neural responses, with mean onset latencies as short as 24 ms for auditory stimuli, consistent with cortical propagation from primary auditory areas.^[13] Subcortical inputs include projections from the intermediate layers of the superior colliculus (SC), which provide tectal feedback via direct pathways, and from the medial dorsal (MD) thalamus, relaying corollary discharge signals to update sensory representations during eye movements. The SC-MD-FEF circuit specifically conveys movement-related copies to stabilize perception across saccades. Top-down modulatory inputs originate from the dorsolateral prefrontal cortex (DLPFC), particularly the principal sulcus region, influencing FEF activity during working memory tasks by providing cognitive context for target selection. Additionally, inputs from the anterior cingulate cortex, including the cingulate eye field, contribute signals related to decision-making and error monitoring in oculomotor control. Most afferent pathways to the FEF are direct corticocortical or subcortico-cortical connections, predominantly glutamatergic and excitatory. Indirect routes, such as those via the basal ganglia or thalamus, supplement these for modulatory functions like corollary discharge.

Efferent outputs

The frontal eye fields (FEF) send descending projections to key brainstem structures involved in saccade execution, including the deep layers of the superior colliculus (SC), the paramedian pontine reticular formation (PPRF), and the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF).^[14]^[15]^[16] These pathways enable the FEF to influence the generation and control of rapid eye movements, with direct inputs to the SC's intermediate and deep layers modulating saccadic burst activity, while projections to the PPRF and riMLF coordinate horizontal and vertical gaze components, respectively.^[17] Cortical efferent outputs from the FEF include connections to the supplementary eye fields (SEF), the contralateral FEF, and regions of the parietal cortex such as the lateral intraparietal area (LIP).^[18]^[19] These projections facilitate interhemispheric coordination and feedback loops for integrating eye movement planning with visuospatial attention, with reciprocal links to the SEF supporting complex sequence generation and to the parietal cortex aiding in target selection and remapping.^[20] The FEF also forms thalamic loops by projecting to the medial dorsal nucleus (MD), which relays signals back to prefrontal areas to sustain cognitive aspects of gaze control. These connections contribute to the integration of oculomotor commands with executive functions in the frontal lobe.^[21] Inhibitory outputs from the FEF involve GABAergic projections to local cortical circuits within the FEF itself; the FEF influences the substantia nigra pars reticulata (SNr) indirectly through projections to the caudate nucleus, which provides GABAergic inhibition to the SNr, helping to suppress unwanted eye movements and maintain fixation.^[17] These mechanisms prevent reflexive saccades and modulate basal ganglia outputs to the SC for selective disinhibition of desired gaze shifts.^[22] Pathway densities from the FEF exhibit a contralateral bias, particularly for horizontal saccades, with stronger projections crossing the midline to the opposite PPRF and SC to drive ipsilesional eye movements.^[15] This asymmetry underlies the lateralized control of conjugate gaze.^[17]

Physiological mechanisms

Neural activity during eye movements

Neurons in the frontal eye fields (FEF) display characteristic firing patterns tied to saccadic eye movements, identified through single-unit recordings in awake primates. A significant proportion of FEF neurons, approximately 54%, exhibit presaccadic activity, including burst-like discharges that peak at rates of 100-200 spikes per second in the 100-200 ms preceding saccade onset. These include visuomovement and movement neurons, which show phasic bursts aligned with impending saccades into specific movement fields, often followed by brief tonic activity during the movement itself. Additionally, buildup neurons demonstrate ramping preparatory activity that gradually increases over hundreds of milliseconds before saccade initiation, reflecting sustained motor preparation.^[23]^[24] The temporal dynamics of FEF neural responses distinguish sensory and motor components during eye movements. Visual responses in FEF neurons typically onset with latencies of 60-150 ms (median 92 ms) following stimulus presentation, reflecting early processing of retinal input. Movement-related bursts commence 100-200 ms (median 152 ms) prior to saccade onset, providing a command signal for execution. In contrast, during smooth pursuit eye movements, FEF neurons in the ventral region sustain tonic firing throughout the duration of tracking, with activity modulated by target velocity and acceleration, often beginning around 100 ms after motion onset and persisting as long as the pursuit continues.^[23]^[25] Direction selectivity is a hallmark of FEF neural activity, with most neurons tuned to contralateral visual fields and preferred saccade directions spanning 360 degrees across the population. Visual neurons show the sharpest tuning (mean tuning width 33°), while movement neurons have broader fields (mean 58°), enabling precise coding of saccade vectors. For combined eye movements, such as when multiple stimuli compete, the distributed activity of FEF neurons supports vector averaging, where the resultant saccade direction and amplitude represent a population-weighted mean of individual neuron preferences. This mechanism has been demonstrated in tasks involving simultaneous targets, where evoked movements align with averaged neural tuning.^[23]^[26] Microstimulation of the FEF provides direct insight into its motor role, evoking fixed-vector saccades that match local neural movement fields. Low currents of 20-50 μA typically elicit saccades with amplitudes of 5-20 degrees in a consistent direction, independent of starting eye position or ongoing activity, with latencies of 30-45 ms. Sites with presaccadic neurons yield lower thresholds (around 50 μA) and saccades correlating highly with the neuron's preferred vector (direction correlation r=0.93; amplitude r=0.81), underscoring the causal link between neural discharge and motor output. Higher currents (>100 μA) may recruit additional sites but can distort vectors.^[27] Single-unit recordings from primate FEF reveal that 70-80% of neurons are modulated by orbital eye position, often through gain fields that scale response magnitude with gaze eccentricity. This position-dependent modulation, observed in both visual and movement-related activity, contributes to spatiotopic representations of intended saccades, independent of retinal coordinates. Such properties ensure accurate updating of movement plans across gaze shifts, with stronger modulation for contralateral positions.^[28]

Retinotopic organization and sensory processing

The frontal eye fields (FEF) exhibit a retinotopic organization that maps the contralateral visual hemifield onto the cortical surface, with a pronounced foveal bias where central visual space receives greater representation than the periphery. This organization features a decreasing cortical magnification factor with increasing eccentricity, such that foveal and paracentral locations are disproportionately amplified relative to peripheral ones. The lateral FEF predominantly encodes foveal representations, while the medial FEF handles more peripheral visual space, facilitating efficient processing for saccadic targeting across the visual field.^[29]^[30] Visual receptive fields of FEF neurons are notably large, often spanning 10–30 degrees of visual angle, and overlap substantially across the neuronal population to provide broad coverage of visual space. These receptive fields display a center-surround structure, characterized by excitatory responses in the central region and suppressive influences in the surrounding areas, which enhances the detection of salient or behaviorally relevant stimuli by suppressing responses to uniform or less informative backgrounds. Unlike the smaller, more precisely tuned fields in primary visual cortex, this organization supports the FEF's role in integrating sensory signals for orienting behaviors.^[31]^[32] The FEF integrates multisensory inputs, with auditory receptive fields spatially aligned to corresponding visual fields, allowing for enhanced neural responses to coincident stimuli from the same location and thereby improving the speed and accuracy of orienting movements. Approximately 64% of FEF neurons respond to auditory targets, with activity levels converging to match visual responses shortly before saccade initiation, underscoring the area's contribution to multisensory motor control.^[33] Spatial encoding in the FEF relies on population coding, where distributed patterns of activation across ensembles of neurons represent specific locations with high precision, rather than through isolated point-to-point mappings as seen in earlier visual areas. This collective neuronal activity enables robust representation of visual targets in eye-centered coordinates, supporting flexible transformations for gaze shifts.^[34] FEF neurons demonstrate adaptation to repeated visual stimuli, exhibiting habituation that substantially reduces response magnitude—often by 20–50%—to the second stimulus, with recovery occurring within approximately 500 ms. This neural habituation helps prioritize novel or changing inputs, optimizing sensory processing for dynamic environments.^[35]

Functions

Saccadic eye movements

The frontal eye fields (FEF) play a central role in the generation of saccadic eye movements, which are rapid, ballistic shifts in gaze that redirect the eyes toward a new point of interest. These movements typically exhibit amplitudes ranging from small fixations to up to 30 degrees and peak velocities reaching approximately 500 degrees per second, characteristics that are evoked through microstimulation of the FEF in primates. The FEF is particularly involved in voluntary or endogenous saccades, which are goal-directed and internally triggered, as opposed to reflexive or exogenous saccades driven by sudden peripheral stimuli; single-neuron recordings demonstrate that FEF activity precedes and modulates voluntary saccades more robustly, facilitating their planning and execution.^[36]^[37]^[38] During saccade planning, FEF neurons encode the intended saccade vector—direction and amplitude—in eye-centered coordinates, integrating visual target location relative to the current gaze position. This representation undergoes perisaccadic remapping, where receptive fields shift predictively toward the postsaccadic locus just before movement onset, maintaining spatial continuity across the saccade; such remapping is observed in a significant proportion of FEF neurons during delayed saccade tasks. Recent studies using local field potentials in macaques have detailed the forward and convergent remapping dynamics in FEF during delayed saccades, confirming its role in spatial updating.^[28]^[39]^[40] For coordination, the FEF exhibits contralateral dominance for horizontal saccades but bilateral activation for vertical components, ensuring precise control over conjugate eye movements through interconnected cortical and subcortical pathways.^[28]^[39] In cognitive tasks like the anti-saccade paradigm, the FEF contributes to suppressing reflexive responses to peripheral cues by inhibiting unwanted eye movements, leveraging connections to prefrontal regions for executive control; neuronal activity in the FEF shows preparatory signals that differentiate pro-saccades from anti-saccades, with enhanced firing for the latter to override automatic tendencies. Quantitatively, the FEF operates within a distributed network for saccade initiation, collaborating with the lateral intraparietal area (LIP) for target selection and the superior colliculus (SC) for motor execution, where rising neural activity in these regions reaches a threshold to trigger the movement.^[41]^[42]^[43]

Visual attention and cognition

The frontal eye fields (FEF) play a crucial role in attentional modulation by enhancing the processing of stimuli at attended locations through gain field mechanisms on sensory neurons in downstream visual areas. Visually responsive neurons in the FEF exhibit spatially selective activity that acts as a top-down signal, modulating the gain of extrastriate cortical neurons to amplify responses to relevant stimuli while suppressing irrelevant ones during covert attention tasks.^[44] This modulation occurs independently of overt eye movements, as evidenced by enhanced FEF activity during visual search without saccades, where it functions like a "mental spotlight" to prioritize perceptual processing. Recent research combining psychophysics, fMRI, and TMS has demonstrated a causal role of the FEF in generating attention-induced ocular dominance shifts, highlighting its influence on binocular vision and attention.^[45]^[46] In feature-based attention, the FEF demonstrates selectivity for specific stimulus attributes such as shape and motion, interacting with area V4 to bias sensory processing toward task-relevant features. Simultaneous recordings from FEF and V4 during visual search tasks reveal that FEF neurons enhance responses to target features (e.g., shape) earlier than V4 (approximately 100 ms post-stimulus onset versus 130 ms), suggesting FEF provides top-down signals that sharpen V4's feature tuning for color and motion without relying solely on spatial cues.^[47] This interaction supports efficient target detection by amplifying neural representations of attended features across the visual field, with FEF shape selectivity correlating to reduced saccades needed to locate targets.^[48] The FEF contributes to working memory by maintaining persistent neural activity that holds spatial information during delay periods in tasks like memory-guided saccades. This delay-period activity in FEF neurons is spatially tuned, encoding cue locations or prospective saccade goals more robustly than in other prefrontal regions, and sustains throughout the memory interval to bridge sensory input and motor output.^[49] Studies indicate this persistent firing persists for the duration of typical delays (e.g., 0.8-1.2 seconds or up to 3-6 seconds in longer tasks), supporting the temporary storage of visuospatial representations essential for guiding delayed responses.^[50] In perceptual decision-making, FEF neurons accumulate evidence through ramping activity in random dot motion discrimination tasks, where firing rates gradually increase with motion coherence and viewing time to reflect the building commitment to a choice. This ramping is choice-selective, with steeper slopes and higher variance in activity for the preferred direction, directly correlating to the animal's eventual decision and indicating FEF's role in integrating sensory evidence for action selection.^[51] Such dynamics highlight the FEF's integration of sensory accumulation with preparatory signals for eye movements.^[52] Recent findings show that FEF neurons signal reward-related information, modulating response strength based on expected value to bias attention toward rewarding stimuli.^[53] Top-down control from the FEF in visual search tasks involves activation that suppresses distractors through interactions with the pulvinar nucleus, enhancing focus on relevant stimuli. FEF signals modulate pulvinar-cortical loops to reduce attentional effects in V4 when disrupted, leading to diminished suppression of irrelevant locations and increased low-frequency oscillations indicative of attentional lapses.^[54] This mechanism allows FEF to exert bias signals that prioritize task goals, facilitating efficient search by inhibiting competing inputs via pulvinar-mediated gating.^[55]

Clinical significance

Effects of lesions

Lesions to the frontal eye fields (FEF) result in distinct oculomotor and attentional deficits, depending on whether the damage is unilateral or bilateral. Unilateral FEF lesions typically produce transient contralateral gaze deviation, lasting from days to weeks, followed by more persistent impairments in generating voluntary saccades toward the contralateral visual field. These deficits manifest as increased latencies and reduced amplitude gains for contralesional saccades, with studies in humans showing latency increases of approximately 40-60 ms in the acute phase for visually guided tasks. Reflexive saccades are relatively preserved, indicating that the FEF plays a primary role in voluntary, endogenously driven eye movements rather than purely reflexive ones.^[56]^[57] Bilateral FEF lesions lead to more severe global oculomotor apraxia, characterized by profound difficulty in initiating voluntary saccades in any direction, while reflexive eye movements remain largely intact. In monkey models, such lesions cause dramatic reductions in the ability to fixate or generate visually triggered saccades, with latencies for memory-guided saccades increasing significantly on both sides. Human cases, though exceedingly rare and often involving broader frontal damage, exhibit similar patterns of impaired saccade initiation, underscoring the FEF's bilateral contribution to central oculomotor control.^[58] Associated symptoms include mild visuospatial neglect, particularly following right-hemisphere lesions. These effects arise from disrupted FEF contributions to attentional orienting, leading to delayed disengagement from fixation and impaired visual scanning. Case studies illustrate these outcomes; for instance, a patient with an ischemic lesion restricted to the left FEF exhibited initial contralateral (rightward) saccade latencies of 312 ms (versus 248 ms in controls), accompanied by gaze deviation, but showed no overt neglect. These cases highlight clinical variability in FEF lesion effects.^[56] Recovery from FEF lesions often involves partial compensation by the contralateral FEF or supplementary eye fields (SEF), occurring over 1-3 months, with normalization of saccade latencies in some cases through oculomotor training or neural plasticity. Persistent deficits in complex voluntary tasks may remain, but reflexive functions typically recover fully.^[59]^[56]

Stimulation and therapeutic applications

Electrical stimulation of the frontal eye fields (FEF) during intraoperative mapping in neurosurgical procedures reliably evokes contralateral saccades, aiding in the precise localization of eloquent cortical areas. Typical parameters include currents of 1-8 mA and frequencies around 50 Hz for stereo-EEG mapping, though higher frequencies up to 500 Hz have been used in some protocols to elicit rapid eye deviations and suppress self-paced saccades.^[60]^[61] Non-invasive techniques such as transcranial magnetic stimulation (TMS) applied over the FEF disrupt oculomotor control, increasing saccade latencies by approximately 20-50 ms depending on timing and intensity, which helps probe the region's role in saccade preparation.^[62] Transcranial direct current stimulation (tDCS) modulates FEF excitability, with anodal stimulation shortening contralateral prosaccade latencies by 6-8 ms and reducing erroneous saccades in antisaccade tasks, thereby biasing attention toward stimulated hemifields.^[63] In therapeutic applications, non-invasive FEF stimulation shows promise for rehabilitating unilateral spatial neglect following stroke, where repetitive TMS over the unaffected hemisphere reduces interhemispheric inhibition and improves contralesional attention when combined with prism adaptation training.^[64] Emerging evidence suggests tDCS targeting the FEF can address oculomotor deficits in Parkinson's disease, such as hypometric saccades, by enhancing cortical excitability and supporting dual-task performance in affected patients.^[65] Recent studies as of 2024 also explore transcranial alternating current stimulation (tACS) over the FEF to modulate attention networks in disorders like ADHD.^[66] Diagnostically, functional MRI (fMRI) activation of the FEF during anti-saccade tasks serves as a marker for assessing network integrity, revealing hypoactivation in the right FEF during preparation phases in adults with attention-deficit/hyperactivity disorder (ADHD), correlated with increased directional errors.^[67] Similarly, reduced FEF recruitment in schizophrenia patients during these tasks indicates impaired inhibitory control, aiding in differential diagnosis from other psychiatric conditions.^[68] Safety considerations for FEF stimulation include a low risk of seizures, estimated at less than 0.1% for single-pulse TMS and up to 1-2% in intraoperative electrical mapping studies, with no reported seizures in standard tDCS protocols.^[69] Updated guidelines from the 2020s emphasize screening for epilepsy history, monitoring during high-frequency repetitive TMS, and adhering to intensity limits (e.g., 110% motor threshold) to minimize adverse events in both research and clinical settings.^[69]

History and research

Early discoveries

The foundational understanding of the frontal eye fields (FEF) emerged in the late 19th century through ablation experiments conducted by David Ferrier on monkeys. In the 1870s, Ferrier demonstrated that surgical removal of the frontal lobe, particularly regions in the superior frontal convolution, resulted in persistent deficits in voluntary conjugate gaze toward the contralateral visual field, while reflexive eye movements remained relatively intact; these findings highlighted the frontal cortex's role in initiating directed eye movements.^[9] The term "frontal eye fields" was established around the turn of the 20th century by Alfred S. F. Grünbaum and Charles Sherrington during their electrical stimulation studies on the cerebral cortex of anthropoid apes. In 1901–1903, they mapped an oculomotor region in the precentral frontal cortex (Brodmann's area 8), where low-intensity stimulation reliably elicited fixed-position conjugate deviations of the eyes to the contralateral side, distinguishing it from adjacent motor areas controlling limb movements.^[70] These experiments refined the anatomical boundaries of the FEF and emphasized its specificity for saccadic eye control, building on Ferrier's earlier localization efforts.^[71] Electrical stimulation techniques advanced FEF characterization in the mid-20th century, particularly through primate experiments in the 1940s and 1950s. Marion Hines's 1940 mapping in chimpanzees identified a frontal oculomotor zone anterior to the arm area, where stimulation produced contraversive saccades of consistent amplitude, evoking them from area 8 without skeletal muscle involvement.^[70] Similarly, Irving H. Wagman's 1950s–early 1960s studies in rhesus monkeys demonstrated that microstimulation of the FEF elicited rapid, contralateral saccades with vector-specific trajectories, providing quantitative evidence of its premotor function for voluntary gaze shifts.^[72]

Modern neuroimaging and studies

Modern neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), have revealed activation peaks in the frontal eye fields (FEF) during voluntary saccades.^[73] These studies demonstrate bilateral BOLD signal increases in the FEF, located near the junction of the precentral and superior frontal sulcus, during tasks involving saccadic eye movements. PET imaging similarly shows FEF activation during voluntary saccades and associated spatial working memory processes, highlighting its role in oculomotor control.^[74] Connectivity analyses using resting-state fMRI further indicate co-activation between the FEF and superior colliculus (SC), underscoring their integrated function in the oculomotor network.^[75] Optogenetic approaches in animal models during the 2010s have provided causal evidence for the FEF's role in visual attention and saccade execution. Selective silencing of FEF neurons via improved optogenetic methods, such as halorhodopsin expression in macaques, significantly increases error rates in memory-guided saccade tasks and alters saccade metrics, including increased latency during specific task epochs.^[76] These findings confirm the FEF's causal involvement in attentional modulation, with inactivation leading to deficits in target selection and movement timing. Computational models incorporating FEF signals have advanced understanding of decision-making under uncertainty in visual search. Recent Bayesian frameworks, applied to FEF neuronal activity, demonstrate how these signals integrate sensory priors to handle variability in target detection, often revealing suboptimal but efficient strategies in human and primate search behaviors.^[77] For instance, models predict that FEF neurons encode anti-Bayesian adjustments to compensate for sensory noise, enhancing predictive accuracy in dynamic environments. In human studies, magnetoencephalography (MEG) has identified 40-60 Hz gamma oscillations originating in the FEF that synchronize with parietal areas, facilitating top-down attentional control over visual processing.^[78] These oscillations reflect enhanced connectivity between frontoparietal networks during spatial tasks. Applications in virtual reality (VR) environments have further explored FEF contributions to spatial cognition, with neuroimaging showing activations in the FEF during VR-based navigation and peripersonal space encoding, linking it to immersive perspective-taking and orientation.^[79] Recent advances as of 2025 leverage AI-driven methods to decode saccade intentions from FEF activity with high accuracy. Machine learning decoders applied to neural recordings from the FEF and related frontal areas achieve 80-90% accuracy in predicting saccade direction and onset, particularly for contralateral targets, enabling real-time brain-computer interfaces for oculomotor research.^[80]

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Computing vector differences using a gain field-like mechanism in ...
We show that visual and pre-saccadic responses of frontal eye field (FEF) neurons are modulated by initial eye position in a way suggestive of a multiplicative ...
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We investigated the topographic organization of visual cortex connections with frontal eye field (FEF), the final stage of cortical processing for saccadic eye ...
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Jun 19, 2017 · In the V1-V3 maps, the coverage density plots show a nearly total contralateral bias, as well as bias toward the fovea over the periphery ( ...
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Neuronal receptive fields (RFs) provide the foundation for understanding systems-level sensory processing. In early visual areas, investigators have mapped ...
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Suppressive Surrounds of Receptive Fields In Monkey Frontal Eye ...
Aug 29, 2012 · Visual receptive fields (RFs) are conventionally established by probing the visual field with small stimuli at different locations and noting ...
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Similar prevalence and magnitude of auditory-evoked and visually ...
We seek to shed light on this signal transformation by comparing the properties of auditory- and visual-evoked activity in the primate frontal eye fields (FEF).
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Transition from Target to Gaze Coding in Primate Frontal Eye Field ...
We show that frontal eye field delay activity (particularly in visuomovement neurons) shows a progressive transition through intermediate target-gaze codes.
[36]
Neuronal adaptation caused by sequential visual stimulation in the ...
We recorded the visual responses of single neurons in the frontal eye field (FEF), a prefrontal area polysynaptically removed from the retina that is involved ...Missing: effects habituation
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Velocity Characteristics of Normal Human Saccades - IOVS
The lower limits of normal mean PV for saccades of 5°, 10°, 20°, and 30° are 114, 167, 188, and 200° per second for conventional EOG and 145,
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Primate frontal eye fields. I. Single neurons discharging ... - PubMed
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Endogenously Generated and Visually Guided Saccades ... - PubMed
The FEF facilitates the generation of voluntary saccatles and also inhibits reflexive saccades to exogenous signals. FEF lesions may disinhibit the ipsilesional ...
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Circuits for presaccadic visual remapping - PMC - PubMed Central
Remapping requires information about upcoming saccades via corollary discharge. Analyses of neurons in a corollary discharge pathway that targets the frontal ...
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Neuronal Correlates for Preparatory Set Associated with Pro ...
Jan 1, 2000 · In addition to visual and saccade-related responses (Bruce and Goldberg, 1985), many FEF neurons display low-frequency prestimulus activity ( ...<|control11|><|separator|>
[42]
[PDF] CONCURRENT, DISTRIBUTED CONTROL OF SACCADE ...
Long-lead burst neurons (LLBNs), also located in the brainstem reticular formation, discharge a high frequency burst of action potentials for saccades into the ...
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Eye movement abnormalities in movement disorders - PMC
Aug 30, 2019 · While horizontal saccades are associated with activity in the contralateral FEF and SC, vertical saccades are associated with activity in ...
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We investigated the link between FEF activity and covert spatial attention by recording from FEF visual and saccade-related neurons in monkeys.
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Feature-based attention in the Frontal Eye Field and area V4 during ...
To investigate the neural mechanisms of feature-based attention, we simultaneously recorded neural responses in the Frontal Eye Field (FEF) and area V4, while ...Missing: seminal | Show results with:seminal
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Persistent Activity During Working Memory From Front to Back
Activity persists during the delay period of memory-guided saccade tasks. The two insets depict a PFC neuron's response when the memory target appears in and ...
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Distinct dynamics of ramping activity in the frontal cortex and ... - NIH
The prefronto-striatal network is involved in many cognitive functions, including perceptual decision making and reward-modulated behaviors.
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The frontal eye fields (FEF) is one source of top-down signals for modulating the visual cortex during spatial attention (Squire et al., 2013), but it could ...
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Dec 7, 2020 · Interference with smooth eye movements and generation of saccades is known to be associated with stimulation of frontal eye fields in superior ...
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Intraoperative Frontal Eye Field Stimulation Elicits Ocular Deviation ...
Intraoperative FEF stimulation may elicit recordable contraversive SEM, and interfere with oculomotor behaviour, suppressing self-paced saccades.Missing: parameters current frequency
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TMS Over Human Frontal Eye Fields Disrupts Trans-saccadic ...
Jul 29, 2009 · The mean latency (±SD) for saccades in the left and right FEF TMS conditions were 224.8 (±60.5 ms) and 257.1 ms (±46.3 ms), respectively, ...
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Transcranial Direct Current Stimulation of the Frontal Eye Fields ...
May 10, 2012 · The goal of the present study was to examine whether tDCS can reach and modulate the excitability of the frontal eye fields (FEF), which is one ...
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Non-Invasive Brain Stimulation in Neglect Rehabilitation: An Update
Here, we review the effects of non-invasive brain stimulation such as transcranial magnetic stimulation (TMS) or transcranial direct current stimulation ...
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Non-invasive brain stimulation enhances motor and cognitive ...
Nov 25, 2024 · Parkinson's disease (PD) induces progressive deficits in motor and ... stimulation modulates neuronal networks in attention deficit ...Missing: FEF | Show results with:FEF
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Preparatory neural networks are impaired in adults with attention ...
It is important to note that human studies using fMRI report increased FEF activation during antisaccade preparation; conversely, saccade neurons in layer V ...
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The Tell-Tale Tasks: A Review of Saccadic Research in Psychiatric ...
The finding that schizophrenia patients display impaired antisaccade task performance relative to healthy controls is a robust one, with over 50 replications to ...
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Safety and recommendations for TMS use in healthy subjects and ...
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Eye fields in the frontal lobes of primates - ScienceDirect.com
Although the DMFC and FEF are both active during the execution of saccadic and smooth pursuit eye movements, the FEF is more dedicated to these functions.
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What makes a frontal area of primate brain the frontal eye field? - PMC
Brodmann human brain areas defined and numbered based on the cytoarchitectural organization of neurons observed in the cerebral cortex using the Nissl stain.
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An enduring map of the motor cortex - The Physiological Society
Jun 28, 2008 · ... (Grünbaum & Sherrington, 1901, 1903). A. S. F. Leyton was not only a ... 1), in what we now call the frontal eye fields. Details are in ...
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Download book PDF
a circumscribed visual area, such as Ferrier, Munk and Luciani have postulated” (loc. ... Sherrington, Grünbaum and C. and O. Vogt on monkeys, and by F. Krause.
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Lesions of the frontal eye field impair pursuit eye movements, but ...
Feb 26, 1993 · ... deficit. ... -Y., Goldberg M.E., Segraves M.A., Ungerleider L.G., Mishkin M. The effect of unilateral ablation of the frontal eye fields on ...
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Saccade-related activity in the prefrontal cortex: its role in eye ...
Type I neurons exhibited burst activity only after the initiation of saccadic eye movement, and this activity lasted for a very short time at the beginning of ...
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Recounting the impact of Hubel and Wiesel - PMC - PubMed Central
Jun 15, 2009 · David Hubel and Torsten Wiesel illuminated our understanding of the visual system with experiments extending over some 25 years.