1
|
Lowe KA, Zinke W, Cosman JD, Schall JD. Frontal eye fields in macaque monkeys: prefrontal and premotor contributions to visually guided saccades. Cereb Cortex 2022; 32:5083-5107. [PMID: 35176752 PMCID: PMC9989351 DOI: 10.1093/cercor/bhab533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/27/2022] Open
Abstract
Neuronal spiking was sampled from the frontal eye field (FEF) and from the rostral part of area 6 that reaches to the superior limb of the arcuate sulcus, dorsal to the arcuate spur when present (F2vr) in macaque monkeys performing memory-guided saccades and visually guided saccades for visual search. Neuronal spiking modulation in F2vr resembled that in FEF in many but not all respects. A new consensus clustering algorithm of neuronal modulation patterns revealed that F2vr and FEF contain a greater variety of modulation patterns than previously reported. The areas differ in the proportions of visuomotor neuron types, the proportions of neurons discriminating a target from distractors during visual search, and the consistency of modulation patterns across tasks. However, between F2vr and FEF we found no difference in the magnitude of delay period activity, the timing of the peak discharge rate relative to saccades, or the time of search target selection. The observed similarities and differences between the 2 cortical regions contribute to other work establishing the organization of eye fields in the frontal lobe and may help explain why FEF in monkeys is identified within granular prefrontal area 8 but in humans is identified within agranular premotor area 6.
Collapse
Affiliation(s)
- Kaleb A Lowe
- Department of Psychology, Vanderbilt University, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center
| | - Wolf Zinke
- Department of Psychology, Vanderbilt University, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center
| | - Joshua D Cosman
- Department of Psychology, Vanderbilt University, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center
| | - Jeffrey D Schall
- Department of Psychology, Vanderbilt University, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center
| |
Collapse
|
2
|
Borra E, Luppino G. Comparative anatomy of the macaque and the human frontal oculomotor domain. Neurosci Biobehav Rev 2021; 126:43-56. [PMID: 33737106 DOI: 10.1016/j.neubiorev.2021.03.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/19/2021] [Accepted: 03/12/2021] [Indexed: 11/15/2022]
Abstract
In non-human primates, at the junction of the prefrontal with the premotor cortex, there is a sector designated as frontal eye field (FEF), involved in controlling oculomotor behavior and spatial attention. Evidence for at least two FEFs in humans is at the basis of the still open issue of the possible homologies between the macaque and the human frontal oculomotor system. In this review article we address this issue suggesting a new view solidly grounded on evidence from the last decade showing that, in macaques, the FEF is at the core of an oculomotor domain in which several distinct areas, including areas 45A and 45B, provide the substrate for parallel processing of different aspects of oculomotor behavior. Based on comparative considerations, we will propose a correspondence between some of the macaque and the human oculomotor fields, thus suggesting sharing of neural substrate for oculomotor control, gaze processing, and orienting attention in space. Accordingly, this article could contribute to settle some aspects of the so-called "enigma" of the human FEF anatomy.
Collapse
Affiliation(s)
- Elena Borra
- University of Parma, Department of Medicine and Surgery, Neuroscience Unit, Italy.
| | - Giuseppe Luppino
- University of Parma, Department of Medicine and Surgery, Neuroscience Unit, Italy
| |
Collapse
|
3
|
Dash S, Peel TR, Lomber SG, Corneil BD. Impairment but not abolishment of express saccades after unilateral or bilateral inactivation of the frontal eye fields. J Neurophysiol 2020; 123:1907-1919. [PMID: 32267202 DOI: 10.1152/jn.00191.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Express saccades are a manifestation of a visual grasp reflex triggered when visual information arrives in the intermediate layers of the superior colliculus (SCi), which in turn orchestrates the lower level brainstem saccade generator to evoke a saccade with a very short latency (~100 ms or less). A prominent theory regarding express saccades generation is that they are facilitated by preparatory signals, presumably from cortical areas, which prime the SCi before the arrival of visual information. Here, we test this theory by reversibly inactivating a key cortical input to the SCi, the frontal eye fields (FEF), while monkeys perform an oculomotor task that promotes express saccades. Across three tasks with a different combination of potential target locations and unilateral or bilateral FEF inactivation, we found a spared ability for monkeys to generate express saccades, despite decreases in express saccade frequency during FEF inactivation. This result is consistent with the FEF having a facilitatory but not critical role in express saccade generation, likely because other cortical areas compensate for the loss of preparatory input to the SCi. However, we also found decreases in the accuracy and peak velocity of express saccades generated during FEF inactivation, which argues for an influence of the FEF on the saccadic burst generator even during express saccades. Overall, our results shed further light on the role of the FEF in the shortest-latency visually-guided eye movements.NEW & NOTEWORTHY Express saccades are the shortest-latency saccade. The frontal eye fields (FEF) are thought to promote express saccades by presetting the superior colliculus. Here, by reversibly inactivating the FEF either unilaterally or bilaterally via cortical cooling, we support this by showing that the FEF plays a facilitative but not critical role in express saccade generation. We also found that FEF inactivation lowered express saccade peak velocity, emphasizing a contribution of the FEF to express saccade kinematics.
Collapse
Affiliation(s)
- Suryadeep Dash
- Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Tyler R Peel
- Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada
| | - Stephen G Lomber
- Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada.,Department of Psychology, University of Western Ontario, London, Ontario, Canada
| | - Brian D Corneil
- Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada.,Department of Psychology, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
4
|
Neromyliotis E, Moschovakis AK. Response properties of saccade-related neurons of the post-arcuate premotor cortex. J Neurophysiol 2018. [DOI: 10.1152/jn.00669.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied the phasic saccade-related discharges of single neurons (S neurons) of the premotor cortex of female rhesus monkeys, mostly in the caudal bank of the arcuate sulcus. As described in previous work from our laboratory (Neromyliotis E, Moschovakis AK. Front Behav Neurosci 11: 1–21, 2017), some of these cells emitted phasic discharges for coordinated movements of the eyes and hand as well as for movements of either effector executed in isolation (motor equivalence, Meq). Other cells (S) did not emit phasic discharges for hand movements unaccompanied by saccades. In contrast to frontal eye field (FEF) neurons, but similar to forelimb-related neurons (H neurons) and Meq cells, the discharges of S cells did not display contralateral bias; their on-directions were as likely to be ipsiversive as contraversive. Because the onset of their discharge preceded that of FEF neurons, S cells are unlikely to convey to their targets corollary discharges of the FEF. We also encountered a small number of neurons that could function as logic gates: cells that discharged for saccades if they were not accompanied by hand movements, cells that discharged for saccades or movements of the hand but not for coordinated movements of both effectors, and cells that discharged only for coordinated movements of the eyes and the hand but not when one of the effectors moved unaccompanied by the other. Our findings are discussed in terms of sequences of decision processes stitching effector-specific motor plans onto effector-invariant movement primitives. NEW & NOTEWORTHY The premotor cortex, traditionally associated with skeletomotor control, is shown to contain cells that emit strong discharges time-linked to saccades but not for hand movements unaccompanied by saccades (S cells). Unlike frontal eye field (FEF) neurons, the S cells of the premotor cortex did not display contralateral bias, and because their presaccadic discharges preceded those of FEF neurons, they are unlikely to serve as conveyors of FEF efferent discharges.
Collapse
Affiliation(s)
- E. Neromyliotis
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology–Hellas, Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - A. K. Moschovakis
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology–Hellas, Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| |
Collapse
|
5
|
Frontal Eye Field Inactivation Reduces Saccade Preparation in the Superior Colliculus but Does Not Alter How Preparatory Activity Relates to Saccades of a Given Latency. eNeuro 2018; 5:eN-NWR-0024-18. [PMID: 29766038 PMCID: PMC5952303 DOI: 10.1523/eneuro.0024-18.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/17/2018] [Accepted: 03/21/2018] [Indexed: 11/23/2022] Open
Abstract
A neural correlate for saccadic reaction times (SRTs) in the gap saccade task is the level of low-frequency activity in the intermediate layers of the superior colliculus (iSC) just before visual target onset: greater levels of such preparatory iSC low-frequency activity precede shorter SRTs. The frontal eye fields (FEFs) are one likely source of iSC preparatory activity, since FEF preparatory activity is also inversely related to SRT. To better understand the FEF’s role in saccade preparation, and the way in which such preparation relates to SRT, in two male rhesus monkeys, we compared iSC preparatory activity across unilateral reversible cryogenic inactivation of the FEF. FEF inactivation increased contralesional SRTs, and lowered ipsilesional iSC preparatory activity. FEF inactivation also reduced rostral iSC activity during the gap period. Importantly, the distributions of SRTs generated with or without FEF inactivation overlapped, enabling us to conduct a novel population-level analyses examining iSC preparatory activity just before generation of SRT-matched saccades. When matched for SRTs, we observed no change during FEF inactivation in the relationship between iSC preparatory activity and SRT-matched saccades across a range of SRTs, even for the occasional express saccade. Thus, while our results emphasize that the FEF has an overall excitatory influence on preparatory activity in the iSC, the communication between the iSC and downstream oculomotor brainstem is unaltered for SRT-matched saccades.
Collapse
|