1
|
Llapashtica E, Sun T, Grattan KTV, Barbur JL. Effects of post-saccadic oscillations on visual processing times. PLoS One 2024; 19:e0302459. [PMID: 38809939 PMCID: PMC11135737 DOI: 10.1371/journal.pone.0302459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 04/03/2024] [Indexed: 05/31/2024] Open
Abstract
Saccadic eye movements enable us to search for the target of interest in a crowded scene or, in the case of goal-directed saccades, to simply bring the image of the peripheral target to the very centre of the fovea. This mechanism extends the use of the superior image processing performance of the fovea over a large visual field. We know that visual information is processed quickly at the end of each saccade but estimates of the times involved remain controversial. This study aims to investigate the processing of visual information during post fixation oscillations of the eyeball. A new psychophysical test measures the combined eye movement response latencies, including fixation duration and visual processing times. When the test is used in conjunction with an eye tracker, each component that makes up the 'integrated saccade latency' time, from the onset of the peripheral stimulus to the correct interpretation of the information carried by the stimulus, can be measured and the discrete components delineated. The results show that the time required to process and encode the stimulus attribute of interest at the end of a saccade is longer than the time needed to carry out the same task in the absence of an eye movement. We propose two principal hypotheses, each of which can account for this finding. 1. The known inhibition of afferent retinal signals during fast eye movements extends beyond the end point of the saccade. 2. The extended visual processing times measured when saccades are involved are caused by the transient loss of spatial resolution due to eyeball instability during post-saccadic oscillations. The latter can best be described as retinal image smear with greater loss of spatial resolution expected for stimuli of low luminance contrast.
Collapse
Affiliation(s)
- Emsal Llapashtica
- The Henry Wellcome Laboratories for Vision Science, Centre for Applied Vision Research, School of Health & Psychological Sciences, University of London, London, United Kingdom
| | - Tong Sun
- Department of Engineering, School of Science and Technology, University of London, London, United Kingdom
| | - Kenneth T. V. Grattan
- Department of Engineering, School of Science and Technology, University of London, London, United Kingdom
| | - John L. Barbur
- The Henry Wellcome Laboratories for Vision Science, Centre for Applied Vision Research, School of Health & Psychological Sciences, University of London, London, United Kingdom
| |
Collapse
|
2
|
Basha D, Kalia SK, Hodaie M, Lopez Rios AL, Lozano AM, Hutchison WD. Beta band oscillations in the motor thalamus are modulated by visuomotor coordination in essential tremor patients. Front Hum Neurosci 2023; 17:1082196. [PMID: 37180551 PMCID: PMC10169705 DOI: 10.3389/fnhum.2023.1082196] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 03/27/2023] [Indexed: 05/16/2023] Open
Abstract
Introduction Beta oscillations in sensorimotor structures contribute to the planning, sequencing, and stopping of movements, functions that are typically associated with the role of the basal ganglia. The presence of beta oscillations (13-30 Hz) in the cerebellar zone of the thalamus (the ventral intermediate nucleus - Vim) indicates that this rhythm may also be involved in cerebellar functions such as motor learning and visuomotor adaptation. Methods To investigate the possible role of Vim beta oscillations in visuomotor coordination, we recorded local field potential (LFP) and multiunit activity from the Vim of essential tremor (ET) patients during neurosurgery for the implantation of deep brain stimulation (DBS) electrodes. Using a computer, patients performed a visuomotor adaptation task that required coordinating center-out movements with incongruent visual feedback imposed by inversion of the computer display. Results The results show that, in ET, Vim beta oscillations of the LFP were lower during the incongruent center-out task than during the congruent orientation. Vim firing rates increased significantly during periods of low beta power, particularly on approach to the peripheral target. In contrast, beta power in the subthalamic nucleus of Parkinson's disease (PD) patients did not differ significantly between the incongruent and the congruent orientation of the center-out task. Discussion The findings support the hypothesis that beta oscillations of the Vim are modulated by novel visuomotor tasks. The inverse relationship between the power of Vim-LFP beta oscillations and Vim firing rates suggest that the suppression of beta oscillations may facilitate information throughput to the thalamocortical circuit by modulation of Vim firing rates.
Collapse
Affiliation(s)
- Diellor Basha
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, Toronto, ON, Canada
| | - Suneil K. Kalia
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Mojgan Hodaie
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Adriana L. Lopez Rios
- Hospital Universitario de San Vicente Fundación, Medellín, Colombia
- Hospital de San Vicente Fundación, Rionegro, Colombia
| | - Andres M. Lozano
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - William D. Hutchison
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
- Hospital de San Vicente Fundación, Rionegro, Colombia
| |
Collapse
|
3
|
Zaino D, Serchi V, Giannini F, Pucci B, Veneri G, Pretegiani E, Rosini F, Monti L, Rufa A. Different saccadic profile in bulbar versus spinal-onset amyotrophic lateral sclerosis. Brain 2023; 146:266-277. [PMID: 35136957 DOI: 10.1093/brain/awac050] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/21/2021] [Accepted: 01/16/2022] [Indexed: 01/11/2023] Open
Abstract
Two clinical phenotypes characterize the onset of amyotrophic lateral sclerosis (ALS): the spinal variant, with symptoms beginning in the limbs, and the bulbar variant, affecting firstly speech and swallowing. The two variants show some distinct features in the histopathology, localization and prognosis, but to which extent they really differ clinically and pathologically remains to be clarified. Recent neuropathological and neuroimaging studies have suggested a broader spreading of the neurodegenerative process in ALS, extending beyond the motor areas, toward other cortical and deep grey matter regions, many of which are involved in visual processing and saccadic control. Indeed, a wide range of eye movement deficits have been reported in ALS, but they have never been used to distinguish the two ALS variants. Since quantifying eye movements is a very sensitive and specific method for the study of brain networks, we compared different saccadic and visual search behaviours across spinal ALS patients (n = 12), bulbar ALS patients (n = 6) and healthy control subjects (n = 13), along with cognitive and MRI measures, with the aim to define more accurately the two patients subgroups and possibly clarify a different underlying neural impairment. We found separate profiles of visually-guided saccades between spinal (short saccades) and bulbar (slow saccades) ALS, which could result from the pathologic involvement of different pathways. We suggest an early involvement of the parieto-collicular-cerebellar network in spinal ALS and the fronto-brainstem circuit in bulbar ALS. Overall, our data confirm the diagnostic value of the eye movements analysis in ALS and add new insight on the involved neural networks.
Collapse
Affiliation(s)
- Domenica Zaino
- Eye tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy.,Neurology and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| | - Valeria Serchi
- Eye tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| | - Fabio Giannini
- Centre for Motor Neuron Diseases, Neurology and Neurophysiology Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| | - Barbara Pucci
- Neurology and Neurophysiology Unit, Department of Medicine, Surgery and Neuroscience, University of Siena, 53100 Siena, Italy
| | - Giacomo Veneri
- Eye tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| | - Elena Pretegiani
- Eye tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| | - Francesca Rosini
- Eye tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| | - Lucia Monti
- Unit of Neuroimaging and Neurointervention, Department of Neurological and Neurosensorial Sciences, AOUS, 53100, Siena, Italy
| | - Alessandra Rufa
- Eye tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| |
Collapse
|
4
|
Saccadic premotor burst neurons and histochemical correlates of their firing patterns in rhesus monkey. J Neurol Sci 2022; 439:120328. [DOI: 10.1016/j.jns.2022.120328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/14/2022] [Accepted: 06/15/2022] [Indexed: 11/20/2022]
|
5
|
Intrinsic bursts facilitate learning of Lévy flight movements in recurrent neural network models. Sci Rep 2022; 12:4951. [PMID: 35322813 PMCID: PMC8943163 DOI: 10.1038/s41598-022-08953-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/09/2022] [Indexed: 11/24/2022] Open
Abstract
Isolated spikes and bursts of spikes are thought to provide the two major modes of information coding by neurons. Bursts are known to be crucial for fundamental processes between neuron pairs, such as neuronal communications and synaptic plasticity. Neuronal bursting also has implications in neurodegenerative diseases and mental disorders. Despite these findings on the roles of bursts, whether and how bursts have an advantage over isolated spikes in the network-level computation remains elusive. Here, we demonstrate in a computational model that not isolated spikes, but intrinsic bursts can greatly facilitate learning of Lévy flight random walk trajectories by synchronizing burst onsets across a neural population. Lévy flight is a hallmark of optimal search strategies and appears in cognitive behaviors such as saccadic eye movements and memory retrieval. Our results suggest that bursting is crucial for sequence learning by recurrent neural networks when sequences comprise long-tailed distributed discrete jumps.
Collapse
|
6
|
Lee H, Hikosaka O. Lateral Habenula Responses During Eye Contact in a Reward Conditioning Task. Front Behav Neurosci 2022; 16:815461. [PMID: 35359583 PMCID: PMC8964066 DOI: 10.3389/fnbeh.2022.815461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/09/2022] [Indexed: 01/23/2023] Open
Abstract
For many animals, social interaction may have intrinsic reward value over and above its utility as a means to the desired end. Eye contact is the starting point of interactions in many social animals, including primates, and abnormal patterns of eye contact are present in many mental disorders. Whereas abundant previous studies have shown that negative emotions such as fear strongly affect eye contact behavior, modulation of eye contact by reward has received scant attention. Here we recorded eye movement patterns and neural activity in lateral habenula while monkeys viewed faces in the context of Pavlovian and instrumental conditioning tasks. Faces associated with larger rewards spontaneously elicited longer periods of eye contact from the monkeys, even though this behavior was not required or advantaged in the task. Concurrently, lateral habenula neurons were suppressed by faces signaling high value and excited by faces signaling low value. These results suggest that the reward signaling of lateral habenula may contribute to social behavior and disorders, presumably through its connections with the basal ganglia.
Collapse
Affiliation(s)
- Hyunchan Lee
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health (NIH), Bethesda, MD, United States
| | | |
Collapse
|
7
|
Drążyk D, Missal M. The oculomotor signature of expected surprise. Sci Rep 2022; 12:2543. [PMID: 35169177 PMCID: PMC8847614 DOI: 10.1038/s41598-022-06403-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/31/2022] [Indexed: 11/09/2022] Open
Abstract
Expected surprise, defined as the anticipation of uncertainty associated with the occurrence of a future event, plays a major role in gaze shifting and spatial attention. In the present study, we analyzed its impact on oculomotor behavior. We hypothesized that the occurrence of anticipatory saccades could decrease with increasing expected surprise and that its influence on visually-guided responses could be different given the presence of sensory information and perhaps competitive attentional effects. This hypothesis was tested in humans using a saccadic reaction time task in which a cue indicated the future stimulus position. In the 'no expected surprise' condition, the visual target could appear only at one previously cued location. In other conditions, more likely future positions were cued with increasing expected surprise. Anticipation was more frequent and pupil size was larger in the 'no expected surprise' condition compared with all other conditions, probably due to increased arousal. The latency of visually-guided saccades increased linearly with the logarithm of surprise (following Hick's law) but their maximum velocity repeated the arousal-related pattern. Therefore, expected surprise affects anticipatory and visually-guided responses differently. Moreover, these observations suggest a causal chain linking surprise, attention and saccades that could be disrupted in attentional or impulse control disorders.
Collapse
Affiliation(s)
- Dominika Drążyk
- Institute of Neurosciences (IONS), Cognition and System (COSY), Université catholique de Louvain, 53 av Mounier, B1.53.04 COSY, 1200, Brussels, Belgium
| | - Marcus Missal
- Institute of Neurosciences (IONS), Cognition and System (COSY), Université catholique de Louvain, 53 av Mounier, B1.53.04 COSY, 1200, Brussels, Belgium.
| |
Collapse
|
8
|
Tyson TL, Flynn-Evans EE, Stone LS. Differential saccade-pursuit coordination under sleep loss and low-dose alcohol. Front Neurosci 2022; 16:1067722. [PMID: 36874639 PMCID: PMC9978352 DOI: 10.3389/fnins.2022.1067722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/07/2022] [Indexed: 02/18/2023] Open
Abstract
Introduction Ocular tracking of a moving object requires tight coordination between smooth pursuit and saccadic eye movements. Normally, pursuit drives gaze velocity to closely match target velocity, with residual position offsets corrected by catch-up saccades. However, how/if common stressors affect this coordination is largely unknown. This study seeks to elucidate the effects of acute and chronic sleep loss, and low-dose alcohol, on saccade-pursuit coordination, as well as that of caffeine. Methods We used an ocular tracking paradigm to assess three metrics of tracking (pursuit gain, saccade rate, saccade amplitude) and to compute "ground lost" (from reductions in steady-state pursuit gain) and "ground recouped" (from increases in steady-state saccade rate and/or amplitude). We emphasize that these are measures of relative changes in positional offsets, and not absolute offset from the fovea. Results Under low-dose alcohol and acute sleep loss, ground lost was similarly large. However, under the former, it was nearly completely recouped by saccades, whereas under the latter, compensation was at best partial. Under chronic sleep restriction and acute sleep loss with a caffeine countermeasure, the pursuit deficit was dramatically smaller, yet saccadic behavior remained altered from baseline. In particular, saccadic rate remained significantly elevated, despite the fact that ground lost was minimal. Discussion This constellation of findings demonstrates differential impacts on saccade-pursuit coordination with low-dose alcohol impacting only pursuit, likely through extrastriate cortical pathways, while acute sleep loss not only disrupts pursuit but also undermines saccadic compensation, likely through midbrain/brainstem pathways. Furthermore, while chronic sleep loss and caffeine-mitigated acute sleep loss show little residual pursuit deficit, consistent with uncompromised cortical visual processing, they nonetheless show an elevated saccade rate, suggesting residual midbrain and/or brainstem impacts.
Collapse
Affiliation(s)
- Terence L Tyson
- Visuomotor Control Laboratory, Human Systems Integration Division, NASA Ames Research Center, Moffett Field, CA, United States
| | - Erin E Flynn-Evans
- Fatigue Countermeasures Laboratory, Human Systems Integration Division, NASA Ames Research Center, Moffett Field, CA, United States
| | - Leland S Stone
- Visuomotor Control Laboratory, Human Systems Integration Division, NASA Ames Research Center, Moffett Field, CA, United States
| |
Collapse
|
9
|
Coding of interceptive saccades in parietal cortex of macaque monkeys. Brain Struct Funct 2021; 226:2707-2723. [PMID: 34468861 PMCID: PMC8448682 DOI: 10.1007/s00429-021-02365-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/23/2021] [Indexed: 10/27/2022]
Abstract
The oculomotor system can initiate remarkably accurate saccades towards moving targets (interceptive saccades) the processing of which is still under debate. The generation of these saccades requires the oculomotor centers to have information about the motion parameters of the target that then must be extrapolated to bridge the inherent processing delays. We investigated to what degree the information about motion of a saccade target is available in the lateral intra-parietal area (area LIP) of macaque monkeys for generation of accurate interceptive saccades. When a multi-layer neural network was trained based on neural discharges from area LIP around the time of saccades towards stationary targets, it was also able to predict the end points of saccades directed towards moving targets. This prediction, however, lagged behind the actual post-saccadic position of the moving target by ~ 80 ms when the whole neuronal sample of 105 neurons was used. We further found that single neurons differentially code for the motion of the target. Selecting neurons with the strongest representation of target motion reduced this lag to ~ 30 ms which represents the position of the moving target approximately at the onset of the interceptive saccade. We conclude that-similarly to recent findings from the Superior Colliculus (Goffart et al. J Neurophysiol 118(5):2890-2901)-there is a continuum of contributions of individual LIP neurons to the accuracy of interceptive saccades. A contribution of other gaze control centers (like the cerebellum or the frontal eye field) that further increase the saccadic accuracy is, however, likely.
Collapse
|
10
|
Li M, Wu J, Ma W, Zhang Z, Zhang M, Li X, Ling Z, Xu X. Spatiotemporal characteristics of postsaccadic dynamic overshoot in young and elderly subjects. iScience 2021; 24:102764. [PMID: 34308287 PMCID: PMC8283153 DOI: 10.1016/j.isci.2021.102764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/14/2021] [Accepted: 06/21/2021] [Indexed: 11/10/2022] Open
Abstract
Saccadic eye movements may not stop steadily but fluctuate briefly, known as saccadic dynamic overshoot (SDO). The reported relationships between SDO and saccadic parameters of main saccade and the effect of aging on SDO are controversial. In addition, it is not clear whether aging-related disease, such as mild cognitive impairment (MCI) and Parkinson disease (PD), causes the specific change of SDO. To address these questions, we analyzed the spatiotemporal features of SDO in young healthy subjects, elderly healthy subjects, and subjects with PD and MCI in three oculomotor tasks. We found two types of SDOs—simple and complex SDO. We confirmed that the frequency and amplitude of SDO were positively correlated with the peak velocity and deceleration of main saccades and increased in elderly subjects; however, they were not significantly different among the three elderly groups. Our results support the previous argument that the oculomotor structure in brainstem and cerebellum directly develop SDO. We classify two types of saccadic dynamic overshoot (SDO): SDOsimple and SDOcomplex Saccades with SDO have higher peak velocity and deceleration than saccades without SDO Elderly subjects show a higher frequency and amplitude of SDO than young subjects Saccades with SDOcomplex occur more frequently in reflexive than voluntary saccades
Collapse
Affiliation(s)
- Min Li
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Junru Wu
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Wenbo Ma
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Zhihao Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Mingsha Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Xuemei Li
- Cadre Medical Department, the 1st Clinical Center, General Hospital of PLA, 28 Fu-Xing Road, Haidian District, Beijing 100853, China
| | - Zhipei Ling
- Department of Neurosurgery, General Hospital of PLA, 28 Fu-Xing Road, Haidian District, Beijing 100853, China
| | - Xin Xu
- Department of Neurosurgery, General Hospital of PLA, 28 Fu-Xing Road, Haidian District, Beijing 100853, China
| |
Collapse
|
11
|
Schall JD, Paré M. The unknown but knowable relationship between Presaccadic Accumulation of activity and Saccade initiation. J Comput Neurosci 2021; 49:213-228. [PMID: 33712942 DOI: 10.1007/s10827-021-00784-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 01/06/2021] [Accepted: 02/16/2021] [Indexed: 12/01/2022]
Abstract
The goal of this short review is to call attention to a yawning gap of knowledge that separates two processes essential for saccade production. On the one hand, knowledge about the saccade generation circuitry within the brainstem is detailed and precise - push-pull interactions between gaze-shifting and gaze-holding processes control the time of saccade initiation, which begins when omnipause neurons are inhibited and brainstem burst neurons are excited. On the other hand, knowledge about the cortical and subcortical premotor circuitry accomplishing saccade initiation has crystalized around the concept of stochastic accumulation - the accumulating activity of saccade neurons reaching a fixed value triggers a saccade. Here is the gap: we do not know how the reaching of a threshold by premotor neurons causes the critical pause and burst of brainstem neurons that initiates saccades. Why this problem matters and how it can be addressed will be discussed. Closing the gap would unify two rich but curiously disconnected empirical and theoretical domains.
Collapse
Affiliation(s)
- Jeffrey D Schall
- Centre for Vision Research, Vision Science to Application, Department of Biology, York University, Ontario, M3J 1P3, Toronto, Canada.
| | - Martin Paré
- Department of Biomedical & Molecular Sciences and of Psychology, Queen's University, Ontario, ON K7L 3N6, Kingston, Canada
| |
Collapse
|
12
|
Vasilev MR, Parmentier FB, Kirkby JA. Distraction by auditory novelty during reading: Evidence for disruption in saccade planning, but not saccade execution. Q J Exp Psychol (Hove) 2020; 74:826-842. [PMID: 33283659 PMCID: PMC8054167 DOI: 10.1177/1747021820982267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Novel or unexpected sounds that deviate from an otherwise repetitive
sequence of the same sound cause behavioural distraction. Recent work
has suggested that distraction also occurs during reading as fixation
durations increased when a deviant sound was presented at the fixation
onset of words. The present study tested the hypothesis that this
increase in fixation durations occurs due to saccadic inhibition. This
was done by manipulating the temporal onset of sounds relative to the
fixation onset of words in the text. If novel sounds cause saccadic
inhibition, they should be more distracting when presented during the
second half of fixations when saccade programming usually takes place.
Participants read single sentences and heard a 120 ms sound when they
fixated five target words in the sentence. On most occasions
(p = .9), the same sine wave tone was presented
(“standard”), while on the remaining occasions (p =
.1) a new sound was presented (“novel”). Critically, sounds were
played, on average, either during the first half of the fixation (0 ms
delay) or during the second half of the fixation (120 ms delay).
Consistent with the saccadic inhibition hypothesis (SIH), novel sounds
led to longer fixation durations in the 120 ms compared to the 0 ms
delay condition. However, novel sounds did not generally influence the
execution of the subsequent saccade. These results suggest that
unexpected sounds have a rapid influence on saccade planning, but not
saccade execution.
Collapse
Affiliation(s)
| | - Fabrice Br Parmentier
- Department of Psychology and Research Institute for Health Sciences (iUNICS), University of the Balearic Islands, Palma, Spain.,Balearic Islands Health Research Institute (IdISBa), Palma, Spain.,School of Psychology, The University of Western Australia, Perth, WA, Australia
| | - Julie A Kirkby
- Department of Psychology, Bournemouth University, Poole, UK
| |
Collapse
|
13
|
Goettker A, Braun DI, Gegenfurtner KR. Dynamic combination of position and motion information when tracking moving targets. J Vis 2020; 19:2. [PMID: 31287856 DOI: 10.1167/19.7.2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To accurately foveate a moving target, the oculomotor system needs to estimate the position of the target at the saccade end, based on information about its position and ongoing movement, while accounting for neuronal delays and execution time of the saccade. We investigated human interceptive saccades and pursuit responses to moving targets defined by high and low luminance contrast or by chromatic contrast only (isoluminance). We used step-ramps with perpendicular directions between vertical target steps of 10 deg/s and horizontal ramps of 2.5 to 20 deg/s to separate errors with respect to the position step of the target in the vertical dimension, and errors related to target motion in the horizontal dimension. Interceptive saccades to targets of high and low luminance contrast landed close to the actual target positions, suggesting relatively accurate estimates of the amount of target displacement. Interceptive saccades to isoluminant targets were less accurate. They landed at positions the target had on average 100 ms before saccade onset. One account of this finding is that the integration of target motion is compromised for isoluminant targets moving in the periphery. In this case, the oculomotor system can use an accurate, but delayed position component, but cannot account for target movement. This deficit was also present for the postsaccadic pursuit speed. For the two luminance conditions, pursuit direction and speed were adjusted depending on the saccadic landing position. The rapid postsaccadic pursuit adjustments suggest shared position- and motion-related signals of target and eye for saccade and pursuit control.
Collapse
|
14
|
Flierman NA, Ignashchenkova A, Negrello M, Thier P, De Zeeuw CI, Badura A. Glissades Are Altered by Lesions to the Oculomotor Vermis but Not by Saccadic Adaptation. Front Behav Neurosci 2019; 13:194. [PMID: 31507389 PMCID: PMC6716469 DOI: 10.3389/fnbeh.2019.00194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 08/08/2019] [Indexed: 11/25/2022] Open
Abstract
Saccadic eye movements enable fast and precise scanning of the visual field, which is partially controlled by the posterior cerebellar vermis. Textbook saccades have a straight trajectory and a unimodal velocity profile, and hence have well-defined epochs of start and end. However, in practice only a fraction of saccades matches this description. One way in which a saccade can deviate from its trajectory is the presence of an overshoot or undershoot at the end of a saccadic eye movement just before fixation. This additional movement, known as a glissade, is regarded as a motor command error and was characterized decades ago but was almost never studied. Using rhesus macaques, we investigated the properties of glissades and changes to glissade kinematics following cerebellar lesions. Additionally, in monkeys with an intact cerebellum, we investigated whether the glissade amplitude can be modulated using multiple adaptation paradigms. Our results show that saccade kinematics are altered by the presence of a glissade, and that glissades do not appear to have any adaptive function as they do not bring the eye closer to the target. Quantification of these results establishes a detailed description of glissades. Further, we show that lesions to the posterior cerebellum have a deleterious effect on both saccade and glissade properties, which recovers over time. Finally, the saccadic adaptation experiments reveal that glissades cannot be modulated by this training paradigm. Together our work offers a functional study of glissades and provides new insight into the cerebellar involvement in this type of motor error.
Collapse
Affiliation(s)
- Nico A Flierman
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Alla Ignashchenkova
- Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Tübingen, Germany
| | - Mario Negrello
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Peter Thier
- Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Tübingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | | |
Collapse
|
15
|
Abstract
Opsoclonus/flutter (O/F) is a rare disorder of the saccadic system. Previously, we modeled O/F that developed in a patient following abuse of anabolic steroids. That model, as in all models of the saccadic system, generates commands to make a change in eye position. Recently, we saw a patient who developed a unique form of opsoclonus following a concussion. The patient had postsaccadic ocular flutter in both directions of gaze, and opsoclonus during fixation and pursuit in the left hemifield. A new model of the saccadic system is needed to account for this gaze-position dependent O/F. We started with our prior model, which contains two key elements, mutual inhibition between inhibitory burst neurons on both sides and a prolonged reactivation time of the omnipause neurons (OPNs). We included new inputs to the OPNs from the nucleus prepositus hypoglossi and the frontal eye fields, which contain position-dependent neurons. This provides a mechanism for delaying OPN reactivation, and creating a gaze-position dependence. A simplified pursuit system was also added, the output of which inhibits the OPNs, providing a mechanism for gaze-dependence during pursuit. The rest of the model continues to generate a command to change eye position.
Collapse
|
16
|
Leigh RJ, Zee DS. Mathematical models: An extension of the clinician's mind. PROGRESS IN BRAIN RESEARCH 2019; 248:19-26. [DOI: 10.1016/bs.pbr.2018.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
17
|
Soetedjo R. Signals driving the adaptation of saccades that require spatial updating. J Neurophysiol 2018; 120:525-538. [PMID: 29694278 PMCID: PMC6139442 DOI: 10.1152/jn.00075.2018] [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: 01/29/2018] [Revised: 04/10/2018] [Accepted: 04/22/2018] [Indexed: 11/22/2022] Open
Abstract
Saccades adapt to persistent natural or artificially imposed dysmetrias. The characteristics and circuitry of saccade adaptation have been revealed using a visually guided task (VGT) where the vectors of the target step and the intended saccade command are the same. However, in real life, another saccade occasionally intervenes before the saccade to the target occurs. This necessitates an updating of the intended saccade to account for the intervening saccadic displacement, which dissociates the visual target signal and the intended saccade command. We determined whether the adaptation process is similar for VGT and updated saccades by studying the transfer of adaptation between them. The ultimate visual target was dissociated from the intended saccade command with double-step saccade tasks (DSTs) in which two targets are flashed sequentially at different locations while the monkey maintains fixation. The resulting saccades toward the first and second targets occur in the dark. The transfer of visually guided saccade adaptation to the second saccades of a DST and vice versa depended on the eccentricity of the second visual target, and not the second saccade command. If a target with the same eccentricity as the adapted target appears briefly during the intersaccadic interval of a DST, more adaptation transfers. Because a brief appearance of the visual target either before the first saccade or during the intersaccadic interval influences how much adaptation transfer the second saccade will express, the processing of adaptation and DST updating may overlap. NEW & NOTEWORTHY Adaptation and the spatial updating of saccades are thought to be independent processes. When we dissociate the visual target and the intended saccade command, the transfer of visually guided saccade adaptation to the saccades of the double-step saccade tasks (DST) and vice versa is driven by a visual not motor error. The visual target has an effect until the second saccade of a DST occurs. Therefore, the processing of adaptation and the spatial updating of saccades may overlap.
Collapse
Affiliation(s)
- Robijanto Soetedjo
- Department of Physiology and Biophysics, University of Washington , Seattle, Washington
- Washington National Primate Research Center, University of Washington , Seattle, Washington
| |
Collapse
|
18
|
Bourrelly C, Quinet J, Goffart L. The caudal fastigial nucleus and the steering of saccades toward a moving visual target. J Neurophysiol 2018; 120:421-438. [PMID: 29641309 DOI: 10.1152/jn.00141.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The caudal fastigial nuclei (cFN) are the output nuclei by which the medio-posterior cerebellum influences the production of visual saccades. We investigated in two head-restrained monkeys their contribution to the generation of interceptive saccades toward a target moving centrifugally by analyzing the consequences of a unilateral inactivation (10 injection sessions). We describe here the effects on saccades made toward a centrifugal target that moved along the horizontal meridian with a constant (10, 20, or 40°/s), increasing (from 0 to 40°/s over 600 ms), or decreasing (from 40 to 0°/s over 600 ms) speed. After muscimol injection, the monkeys were unable to foveate the current location of the moving target. The horizontal amplitude of interceptive saccades was reduced during contralesional target motions and hypermetric during ipsilesional ones. For both contralesional and ipsilesional saccades, the magnitude of dysmetria increased with target speed. However, the use of accelerating and decelerating targets revealed that the dependence of dysmetria upon target velocity was not due to the current velocity but to the required amplitude of saccade. We discuss these results in the framework of two hypotheses, the so-called "dual drive" and "bilateral" hypotheses. NEW & NOTEWORTHY Unilateral inactivation of the caudal fastigial nucleus impairs the accuracy of saccades toward a moving target. Like saccades toward a static target, interceptive saccades are hypometric when directed toward the contralesional side and hypermetric when they are ipsilesional. The dysmetria depends on target velocity, but the use of accelerating or decelerating targets reveals that velocity is not the crucial parameter. We extend the bilateral fastigial control of saccades and fixation to the production of interceptive saccades.
Collapse
Affiliation(s)
- Clara Bourrelly
- Institut de Neurosciences de la Timone, UMR 7289, Centre National de la Recherche Scientifique, Aix-Marseille Université , Marseille , France.,Laboratoire Psychologie de la Perception, UMR 8242, Centre National de la Recherche Scientifique, Université Paris Descartes , Paris , France
| | - Julie Quinet
- Institut de Neurosciences de la Timone, UMR 7289, Centre National de la Recherche Scientifique, Aix-Marseille Université , Marseille , France
| | - Laurent Goffart
- Institut de Neurosciences de la Timone, UMR 7289, Centre National de la Recherche Scientifique, Aix-Marseille Université , Marseille , France
| |
Collapse
|
19
|
|
20
|
Blundell J, Frisson S, Chakrapani A, Gissen P, Hendriksz C, Vijay S, Olson A. Oculomotor abnormalities in children with Niemann-Pick type C. Mol Genet Metab 2018; 123:159-168. [PMID: 29191430 DOI: 10.1016/j.ymgme.2017.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/14/2017] [Accepted: 11/14/2017] [Indexed: 11/21/2022]
Abstract
Niemann-Pick type C (NP-C) is a rare recessive disorder associated with progressive supranuclear gaze palsy. Degeneration occurs initially for vertical saccades and later for horizontal saccades. There are studies of oculomotor degeneration in adult NP-C patients [1, 2] but no comparable studies in children. We used high-resolution video-based eye tracking to record monocular vertical and horizontal eye movements in 2 neurological NP-C patients (children with clinically observable oculomotor abnormalities) and 3 pre-neurological NP-C patients (children without clinically observable oculomotor abnormalities). Saccade onset latency, saccade peak velocity and saccade curvature were compared to healthy controls (N=77). NP-C patients had selective impairments of vertical saccade peak velocity and vertical saccade curvature, with slower peak velocities and greater curvature. Changes were more pronounced in neurological than pre-neurological patients, showing that these measures are sensitive to disease progress, but abnormal curvature and slowed downward saccades were present in both groups, showing that eye-tracking can register disease-related changes before these are evident in a clinical exam. Both slowing, curvature and the detailed characteristics of the curvature we observed are predicted by the detailed characteristics of RIMLF population codes. Onset latencies were not different from healthy controls. High-resolution video-based eye tracking is a promising sensitive and objective method to measure NP-C disease severity and neurological onset. It may also help evaluate responses to therapeutic interventions.
Collapse
Affiliation(s)
- James Blundell
- The University of Birmingham, School of Psychology, United Kingdom.
| | - Steven Frisson
- The University of Birmingham, School of Psychology, United Kingdom
| | | | - Paul Gissen
- Great Ormond Street Hospital for Children, University College London, Institute of Child Health, United Kingdom
| | - Chris Hendriksz
- Salford Royal NHS Foundation Trust, University of Pretoria, Paediatrics and Child Health, South Africa
| | | | - Andrew Olson
- The University of Birmingham, School of Psychology, United Kingdom
| |
Collapse
|
21
|
Song JH. Abandoning and modifying one action plan for alternatives. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0195. [PMID: 28242729 DOI: 10.1098/rstb.2016.0195] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2016] [Indexed: 11/12/2022] Open
Abstract
Visual scenes are often complex and crowded with many different objects. To interact effectively, we must choose one object at a time as a goal for action. Certain external cues can act as a stop signal, quickly cancelling an ongoing action. Less recognized are internal signals. These can come from recent experience, anticipated action outcomes, cognitive states, and when attention is captured by a salient object. These signals elevate one action plan over alternatives and can quickly modify an initial choice. Here, we focus on these internal processes responsible for selecting, abandoning and modifying action plans. We first highlight how the brain resolves competition among multiple action plans. Critical is the existence of parallel motor planning processes, which allow efficient and timely changes. Then, we discuss how the action system interplays with perception, attention and memory processes to bias action selection and suppress or modify erroneous selections. Subsequently, we show how tracking the continuous modification of action trajectories can provide a tool to read out changes in internal cognitive states. Taken together, we shed light on a broader view that sensorimotor networks can continuously modify actions through simultaneous evaluation of alternative activities in concert with widely distributed perceptual and cognitive networks.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'.
Collapse
Affiliation(s)
- Joo-Hyun Song
- Department of Cognitive, Linguistic and Psychological Sciences, Brown University, PO Box 1821, Providence, RI 02912, USA
| |
Collapse
|
22
|
Coe BC, Munoz DP. Mechanisms of saccade suppression revealed in the anti-saccade task. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0192. [PMID: 28242726 DOI: 10.1098/rstb.2016.0192] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2016] [Indexed: 01/03/2023] Open
Abstract
The anti-saccade task has emerged as an important tool for investigating the complex nature of voluntary behaviour. In this task, participants are instructed to suppress the natural response to look at a peripheral visual stimulus and look in the opposite direction instead. Analysis of saccadic reaction times (SRT: the time from stimulus appearance to the first saccade) and the frequency of direction errors (i.e. looking toward the stimulus) provide insight into saccade suppression mechanisms in the brain. Some direction errors are reflexive responses with very short SRTs (express latency saccades), while other direction errors are driven by automated responses and have longer SRTs. These different types of errors reveal that the anti-saccade task requires different forms of suppression, and neurophysiological experiments in macaques have revealed several potential mechanisms. At the start of an anti-saccade trial, pre-emptive top-down inhibition of saccade generating neurons in the frontal eye fields and superior colliculus must be present before the stimulus appears to prevent express latency direction errors. After the stimulus appears, voluntary anti-saccade commands must compete with, and override, automated visually initiated saccade commands to prevent longer latency direction errors. The frequencies of these types of direction errors, as well as SRTs, change throughout the lifespan and reveal time courses for development, maturation, and ageing. Additionally, patients diagnosed with a variety of neurological and/or psychiatric disorders affecting the frontal lobes and/or basal ganglia produce markedly different SRT distributions and types of direction errors, which highlight specific deficits in saccade suppression and inhibitory control. The anti-saccade task therefore provides valuable insight into the neural mechanisms of saccade suppression and is a valuable tool in a clinical setting.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'.
Collapse
Affiliation(s)
- Brian C Coe
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada K7l 3N6
| | - Douglas P Munoz
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada K7l 3N6
| |
Collapse
|
23
|
Federighi P, Ramat S, Rosini F, Pretegiani E, Federico A, Rufa A. Characteristic Eye Movements in Ataxia-Telangiectasia-Like Disorder: An Explanatory Hypothesis. Front Neurol 2017; 8:596. [PMID: 29170652 PMCID: PMC5684103 DOI: 10.3389/fneur.2017.00596] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 10/24/2017] [Indexed: 01/23/2023] Open
Abstract
Objective To investigate cerebellar dysfunctions and quantitatively characterize specific oculomotor changes in ataxia-telangiectasia-like disorder (ATLD), a rare autosomal recessive disease caused by mutations in the MRE11 gene. Additionally, to further elucidate the pathophysiology of cerebellar damage in the ataxia-telangiectasia (AT) spectrum disorders. Methods Saccade dynamics, metrics, and visual fixation deficits were investigated in two Italian adult siblings with genetically confirmed ATLD. Visually guided saccades were compared with those of 40 healthy subjects. Steady fixation was tested in primary and eccentric positions. Quantitative characterization of saccade parameters, saccadic intrusions (SI), and nystagmus was performed. Results Patients showed abnormally hypermetric and fast horizontal saccades to the left and greater inaccuracy than healthy subjects in all saccadic eye movements. Eye movement abnormalities included slow eye movements that preceded the initial saccade. Horizontal and vertical spontaneous jerk nystagmus, gaze-evoked, and rebound nystagmus were evident. Fixation was interrupted by large square-wave jerk SI and macrosaccadic oscillations. Conclusion Slow eye movements accompanying saccades, SI, and cerebellar nystagmus are frequently seen in AT patients, additionally our ATLD patients showed the presence of fast and hypermetric saccades suggesting damage of granule cell-parallel fiber-Purkinje cell synapses of the cerebellar vermis. A dual pathogenetic mechanism involving neurodevelopmental and neurodegenerative changes is hypothesized to explain the peculiar phenotype of this disease.
Collapse
Affiliation(s)
- Pamela Federighi
- Eye Tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Stefano Ramat
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | - Francesca Rosini
- Eye Tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Elena Pretegiani
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Antonio Federico
- UOC Neurology and Neurometabolic Diseases, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Alessandra Rufa
- Eye Tracking and Visual Application Lab (EVA Lab), Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| |
Collapse
|
24
|
Goffart L, Bourrelly C, Quinet J. Synchronizing the tracking eye movements with the motion of a visual target: Basic neural processes. PROGRESS IN BRAIN RESEARCH 2017; 236:243-268. [PMID: 29157414 DOI: 10.1016/bs.pbr.2017.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In primates, the appearance of an object moving in the peripheral visual field elicits an interceptive saccade that brings the target image onto the foveae. This foveation is then maintained more or less efficiently by slow pursuit eye movements and subsequent catch-up saccades. Sometimes, the tracking is such that the gaze direction looks spatiotemporally locked onto the moving object. Such a spatial synchronism is quite spectacular when one considers that the target-related signals are transmitted to the motor neurons through multiple parallel channels connecting separate neural populations with different conduction speeds and delays. Because of the delays between the changes of retinal activity and the changes of extraocular muscle tension, the maintenance of the target image onto the fovea cannot be driven by the current retinal signals as they correspond to past positions of the target. Yet, the spatiotemporal coincidence observed during pursuit suggests that the oculomotor system is driven by a command estimating continuously the current location of the target, i.e., where it is here and now. This inference is also supported by experimental perturbation studies: when the trajectory of an interceptive saccade is experimentally perturbed, a correction saccade is produced in flight or after a short delay, and brings the gaze next to the location where unperturbed saccades would have landed at about the same time, in the absence of visual feedback. In this chapter, we explain how such correction can be supported by previous visual signals without assuming "predictive" signals encoding future target locations. We also describe the basic neural processes which gradually yield the synchronization of eye movements with the target motion. When the process fails, the gaze is driven by signals related to past locations of the target, not by estimates to its upcoming locations, and a catch-up is made to reinitiate the synchronization.
Collapse
Affiliation(s)
- Laurent Goffart
- Institut de Neurosciences de la Timone, UMR 7289, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille, France.
| | - Clara Bourrelly
- Institut de Neurosciences de la Timone, UMR 7289, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille, France; Laboratoire Psychologie de la Perception, UMR 8242, Centre National de la Recherche Scientifique, Université Paris Descartes, Paris, France
| | - Julie Quinet
- Institut de Neurosciences de la Timone, UMR 7289, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille, France
| |
Collapse
|
25
|
Goffart L, Cecala AL, Gandhi NJ. The superior colliculus and the steering of saccades toward a moving visual target. J Neurophysiol 2017; 118:2890-2901. [PMID: 28904104 DOI: 10.1152/jn.00506.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/13/2017] [Accepted: 09/13/2017] [Indexed: 11/22/2022] Open
Abstract
Following the suggestion that a command encoding current target location feeds the oculomotor system during interceptive saccades, we tested the involvement of the deep superior colliculus (dSC). Extracellular activity of 52 saccade-related neurons was recorded in three monkeys while they generated saccades to targets that were static or moving along the preferred axis, away from (outward) or toward (inward) a fixated target with a constant speed (20°/s). Vertical and horizontal motions were tested when possible. Movement field (MF) parameters (boundaries, preferred vector, and firing rate) were estimated after spline fitting of the relation between the average firing rate during the motor burst and saccade amplitude. During radial target motions, the inner MF boundary shifted in the motion direction for some, but not all, neurons. Likewise, for some neurons, the lower boundaries were shifted upward during upward motions and the upper boundaries downward during downward motions. No consistent change was observed during horizontal motions. For some neurons, the preferred vectors were also shifted in the motion direction for outward, upward, and "toward the midline" target motions. The shifts of boundary and preferred vector were not correlated. The burst firing rate was consistently reduced during interceptive saccades. Our study demonstrates an involvement of dSC neurons in steering the interceptive saccade. When observed, the shifts of boundary in the direction of target motion correspond to commands related to past target locations. The absence of shift in the opposite direction implies that dSC activity does not issue predictive commands related to future target location.NEW & NOTEWORTHY The deep superior colliculus is involved in steering the saccade toward the current location of a moving target. During interceptive saccades, the active population consists of a continuum of cells ranging from neurons issuing commands related to past locations of the target to neurons issuing commands related to its current location. The motor burst of collicular neurons does not contain commands related to the future location of a moving target.
Collapse
Affiliation(s)
- Laurent Goffart
- Institut de Neurosciences de la Timone, UMR 7289 CNRS, Aix-Marseille Université, Marseille, France;
| | - Aaron L Cecala
- Department of Biology, Elizabethtown College, Elizabethtown, Pennsylvania; and
| | - Neeraj J Gandhi
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| |
Collapse
|
26
|
Noorani I, Carpenter RHS. Not moving: the fundamental but neglected motor function. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160190. [PMID: 28242724 PMCID: PMC5332849 DOI: 10.1098/rstb.2016.0190] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2016] [Indexed: 01/04/2023] Open
Abstract
The function of the motor system in preventing rather than initiating movement is often overlooked. Not only are its highest levels predominantly, and tonically, inhibitory, but in general behaviour it is often intermittent, characterized by relatively short periods of activity separated by longer periods of stillness: for most of the time we are not moving, but stationary. Furthermore, these periods of immobility are not a matter of inhibition and relaxation, but require us to expend almost as much energy as when we move, and they make just as many demands on the central nervous system in controlling their performance. The mechanisms that stop movement and maintain immobility have been a greatly neglected area of the study of the brain. This paper introduces the topics to be examined in this special issue of Philosophical Transactions, discussing the various types of stopping and stillness, the problems that they impose on the motor system, the kinds of neural mechanism that underlie them and how they can go wrong.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'.
Collapse
Affiliation(s)
- Imran Noorani
- Department of Physiology, Development and Neuroscience, University of Cambridge CB2 3EG, UK
| | - R H S Carpenter
- Department of Physiology, Development and Neuroscience, University of Cambridge CB2 3EG, UK
| |
Collapse
|