The Experts below are selected from a list of 3609 Experts worldwide ranked by ideXlab platform
Jason J. S. Barton - One of the best experts on this subject based on the ideXlab platform.
-
The inter-trial effect of prepared but not executed Antisaccades
Experimental Brain Research, 2014Co-Authors: Shanna Yeung, Cristina Rubino, Jaya Viswanathan, Jason J. S. BartonAbstract:A preceding Antisaccade increases the latency of the saccade in the next trial. Whether this inter-trial effect is generated by the preparation or the execution of the Antisaccade is not certain. Our goal was to examine the inter-trial effects from trials on which subjects prepared an Antisaccade but did not make one. We tested 15 subjects on blocks of randomly ordered prosaccades and Antisaccades. An instructional cue at fixation indicated whether a prosaccade or Antisaccade was required, with the target appearing 2 s later. On 20 % of Antisaccade trials, the target did not appear (prepared-only Antisaccade trials). We analyzed the latencies of all correct prosaccades or Antisaccades preceded by correctly executed trials. The latencies of prosaccade trials were 15 ms shorter if they were preceded by prosaccades than if the prior trial was an Antisaccade. Prosaccades preceded by trials on which Antisaccades were cued but not executed also showed prolonged latencies that were equivalent to those preceded by executed Antisaccades. We conclude that the inter-trial effects from a prior Antisaccade are generated by its preparation rather than its execution. This may reflect persistence of pre-target preparatory activity from the prior trial to affect that of the next trial in structures like the superior colliculus and frontal eye field.
-
The global effect for Antisaccades
Experimental Brain Research, 2012Co-Authors: Jayalakshmi Viswanathan, Jason J. S. BartonAbstract:In the global effect, prosaccades are deviated to a position intermediate between two targets or between a distractor and a target, which may reflect spatial averaging in a map encoded by the superior colliculus. Antisaccades differ from prosaccades in that they dissociate the locations of the stimulus and goal and generate weaker collicular activity. We used these Antisaccade properties to determine whether the global effect was generated in stimulus or goal computations, and whether the global effect would be larger for Antisaccades, as predicted by collicular averaging. In the first two experiments, human subjects performed Antisaccades while distractors were placed in the vicinity of either the stimulus or the saccadic goal. Global effects occurred only for goal-related and not for stimulus-related distractors, indicating that this effect emerges from interactions with motor representations. In the last experiment, subjects performed prosaccades and Antisaccades with and without goal-related distractors. When the results were adjusted for differences in response latency, the global effect for rapid responses was three to four times larger for Antisaccades than for prosaccades. Finally, we compared our findings with predictions from collicular models, to quantitatively test the spatial averaging hypothesis: we found that our results were consistent with the predictions of a collicular model. We conclude that the Antisaccade global effect shows properties compatible with spatial averaging in collicular maps and likely originates in layers with neural activity related to goal rather than stimulus representations.
-
Response selection in prosaccades, Antisaccades, and other volitional saccades
Experimental Brain Research, 2012Co-Authors: Lisa Kloft, Benedikt Reuter, Jayalakshmi Viswanathan, Norbert Kathmann, Jason J. S. BartonAbstract:Saccades made to the opposite side of a visual stimulus (Antisaccades) and to central cues (simple volitional saccades) both require active response selection but whether the mechanisms of response selection differ between these tasks is unclear. Response selection can be assessed by increasing the number of response alternatives: this leads to increased reaction times when response selection is more demanding. We compared the reaction times of prosaccades, Antisaccades, saccades cued by a central arrow, and saccades cued by a central number, in blocks of either two or six possible responses. In the two-response blocks, reaction times were fastest for prosaccades and Antisaccades, and slowest for arrow-cued and number-cued saccades. Increasing response alternatives from two to six caused a paradoxical reduction in reaction times of prosaccades, had no effect on arrow-cued saccades, and led to a large increase in reaction times of number-cued saccades. For Antisaccade reaction times, the effect of increasing response alternatives was intermediate, greater than that for arrow-cued saccades but less than that for number-cued saccades. We suggest that this pattern of results may reflect two components of saccadic processing: (a) response triggering, which is more rapid with a peripheral stimulus as in the prosaccade and Antisaccade tasks and (b) response selection, which is more demanding for the Antisaccade and number-cued saccade tasks, and more automatic when there is direct stimulus–response mapping as with prosaccades, or over-learned symbols as with arrow-cued saccades.
-
Antisaccades generate two types of saccadic inhibition.
Biological Psychology, 2011Co-Authors: Mathias Abegg, Nishant Sharma, Jason J. S. BartonAbstract:To make an Antisaccade away from a stimulus, one must also suppress the more reflexive prosaccade to the stimulus. Whether this inhibition is diffuse or specific for saccade direction is not known. We used a paradigm examining inter-trial carry-over effects. Twelve subjects performed sequences of four identical Antisaccades followed by sequences of four prosaccades randomly directed at the location of the Antisaccade stimulus, the location of the Antisaccade goal, or neutral locations. We found two types of persistent Antisaccade-related inhibition. First, prosaccades in any direction were delayed only in the first trial after the Antisaccades. Second, prosaccades to the location of the Antisaccade stimulus were delayed more than all other prosaccades, and this persisted from the first to the fourth subsequent trial. These findings are consistent with both a transient global inhibition and a more sustained focal inhibition specific for the location of the Antisaccade stimulus.
-
Abnormally persistent fMRI activation during Antisaccades in schizophrenia: a neural correlate of perseveration?
Schizophrenia Research, 2011Co-Authors: Kara A. Dyckman, Jason J. S. Barton, Yigal Agam, Mark G. Vangel, Donald C. Goff, Dara S. ManoachAbstract:article Objective: Impaired Antisaccade performance is a consistent cognitive finding in schizophrenia. Antisaccades require both response inhibition and volitional motor programming, functions that are essential to flexible responding. We investigated whether abnormal timing of hemodynamic responses (HDRs) to Antisaccades might contribute to perseveration of ocular motor responses in schizophrenia. We focused on the frontal eye field (FEF), which has been implicated in the persistent effects of Antisaccades on subsequent responses in healthy individuals. Method: Eighteen chronic, medicated schizophrenia outpatients and 15 healthy controls performed Antisaccades and prosaccades during functional MRI. Finite impulse response models provided unbiased estimates of event-related HDRs. We compared groups on the peak amplitude, time-to-peak, and full-width half-max of the HDRs. Results: In patients, HDRs in bilateral FEF were delayed and prolonged but ultimately of similar amplitude to that of controls. These abnormalities were present for Antisaccades, but not prosaccades, and were not seen in a control region. More prolonged HDRs predicted slower responses in trials that followed an Antisaccade. This suggests that persistent FEF activity following an Antisaccade contributes to inter-trial effects on latency. Conclusions: Delayed and prolonged HDRs for Antisaccades in schizophrenia suggest that the functions necessary for successful Antisaccade performance take longer to implement and are more persistent. If abnormally persistent neural responses on cognitively demanding tasks are a more general feature of schizophrenia, they may contribute to response perseveration, a classic behavioral abnormality. These findings also underscore the importance of evaluating the temporal dynamics of neural activity to understand cognitive dysfunction in schizophrenia.
Ulrich Ettinger - One of the best experts on this subject based on the ideXlab platform.
-
cerebral blood flow responses during prosaccade and Antisaccade preparation in major depression
European Archives of Psychiatry and Clinical Neuroscience, 2019Co-Authors: Alexandra Hoffmann, Ulrich Ettinger, Casandra I Montoro, Gustavo Reyes A Del Paso, Stefan DuschekAbstract:While impairments in executive functions have been well established in major depressive disorder (MDD), specific deficits in proactive control have scarcely been studied so far. Proactive control refers to cognitive processes during anticipation of a behaviorally relevant event that facilitate readiness to react. In this study, cerebral blood flow responses were investigated in MDD patients during a precued Antisaccade task requiring preparatory attention and proactive inhibition. Using functional transcranial Doppler sonography, blood flow velocities in the middle cerebral arteries of both hemispheres were recorded in 40 MDD patients and 40 healthy controls. In the task, a target appeared left or right of the fixation point 5 s after a cuing stimulus; subjects had to move their gaze to the target (prosaccade) or its mirror image position (Antisaccade). Video-based eye-tracking was applied for ocular recording. A right dominant blood flow increase arose during prosaccade and Antisaccade preparation, which was smaller in MDD patients than controls. Patients exhibited a higher error rate than controls for Antisaccades but not prosaccades. The smaller blood flow response may reflect blunted anticipatory activation of the dorsolateral prefrontal and inferior parietal cortices in MDD. The patients’ increased Antisaccade error rate suggests deficient inhibitory control. The findings support the notion of impairments in proactive control in MDD, which are clinically relevant as they may contribute to the deficits in cognition and behavioral regulation that characterize the disorder.
-
Antisaccade and prosaccade eye movements in individuals clinically at risk for psychosis comparison with first episode schizophrenia and prediction of conversion
European Archives of Psychiatry and Clinical Neuroscience, 2019Co-Authors: Luca Kleineidam, Ingo Frommann, Stephan Ruhrmann, Joachim Klosterkotter, Anke Brockhausdumke, Wolfgang Wolwer, Wolfgang Gaebel, Wolfgang Maier, Michael Wagner, Ulrich EttingerAbstract:Saccadic eye movements are well-described markers of cerebral function and have been widely studied in schizophrenia spectrum populations. However, less is known about saccades in individuals clinically at risk for schizophrenia. Therefore, we studied individuals in an at-risk mental state (ARMS) (N = 160), patients in their first episode of schizophrenia (N = 32) and healthy controls (N = 75). N = 88 ARMS participants showed an early at-risk mental state (E-ARMS), defined by cognitive-perceptive basic symptoms (COPER) or a combination of risk and loss of function, whereas N = 72 were in a late at-risk mental state (L-ARMS), defined by attenuated psychotic symptoms or brief limited intermittent psychotic symptoms. We examined prosaccades, reflecting overt attentional shifts, and Antisaccades, measuring inhibitory control, as well as their relationship as an indicator of the interplay of bottom–up and top–down influences. L-ARMS but not E-ARMS participants had increased Antisaccade latencies compared to controls. First-episode patients had higher Antisaccade error rates compared to E-ARMS participants and controls, and increased latencies compared to all other groups. Prosaccade latencies did not differ between groups. We observed the expected negative correlation between prosaccade latency and Antisaccade error rate, indicating that individuals with shorter prosaccade latencies made more Antisaccade errors. The magnitude of the association did not differ between groups. No saccadic measure predicted conversion to psychosis within 2 years. These findings confirm the existence of Antisaccade impairments in patients with schizophrenia and provide evidence that volitional response generation in the Antisaccade task may be affected even before onset of clinically overt psychosis.
-
development of a cued pro and Antisaccade paradigm an indirect measure to explore automatic components of sexual interest
Archives of Sexual Behavior, 2017Co-Authors: Verena A Oberlader, Ulrich Ettinger, Rainer Banse, Alexander F SchmidtAbstract:We developed a cued pro- and Antisaccade paradigm (CPAP) to explore automatic components of sexual interest. Heterosexual participants (n = 32 women, n = 25 men) had to perform fast eye movements toward and away from sexually relevant or irrelevant stimuli across a congruent (i.e., prosaccade toward sexually relevant stimuli, Antisaccade away from sexually irrelevant stimuli) and an incongruent condition (i.e., prosaccade toward sexually irrelevant stimuli, Antisaccade away from sexually relevant stimuli). We hypothesized that pro- and Antisaccade performance would be influenced by the sexual interest-specific relevance of the presented stimulus (i.e., nude female or male stimulus) and the instructed task (i.e., pro- or Antisaccade) and, thus, differ meaningfully between conditions. Results for prosaccades toward sexually relevant stimuli in the congruent condition showed that error rates were lower and latencies were shorter compared with prosaccades toward sexually irrelevant stimuli in the incongruent condition, but only for male participants. In addition, error rates for Antisaccades away from sexually irrelevant stimuli in the congruent condition were lower than for Antisaccades away from sexually relevant stimuli in the incongruent condition, for both female and male participants. Latencies of Antisaccades, however, did not differ between conditions. In comparison with established indirect sexual interest paradigms, the CPAP benefits from measuring highly automated processes less prone to deliberate control. To this end, the CPAP could be applied to explore the interplay of early automatic and deliberate components of sexual information processing.
-
Functional magnetic resonance imaging of sensorimotor transformations in saccades and Antisaccades
NeuroImage, 2014Co-Authors: Nora A. Herweg, Bernd Weber, Anna-maria Kasparbauer, Inga Meyhöfer, Maria Steffens, Nikolaos Smyrnis, Ulrich EttingerAbstract:Abstract Saccades to peripheral targets require a direct visuomotor transformation. In contrast, Antisaccades, saccades in opposite direction of a peripheral target, require more complex transformation processes due to the inversion of the spatial vector. Here, the differential neural mechanisms underlying sensorimotor control in saccades and Antisaccades were investigated using functional magnetic resonance imaging (fMRI) at 3 T field strength in 22 human volunteers. We combined a task factor (prosaccades: look towards target; Antisaccades: look away from target) with a parametric factor of transformation demand (single vs. multiple peripheral targets) in a two-factorial block design. Behaviorally, a greater number of peripheral targets resulted in decreased spatial accuracy and increased reaction times in Antisaccades. No effects were seen on the percentage of Antisaccade direction errors or on any prosaccade measures. Neurally, a greater number of targets led to increased BOLD signal in the posterior parietal cortex (PPC) bilaterally. This effect was partially qualified by an interaction that extended into somatosensory cortex, indicating greater increases during Antisaccades than prosaccades. The results implicate the PPC as a sensorimotor interface that is especially important in nonstandard mapping for Antisaccades and point to a supportive role of somatosensory areas in Antisaccade sensorimotor control, possibly by means of proprioceptive processes.
-
Antisaccade performance in schizophrenia a neural model of decision making in the superior colliculus
Frontiers in Neuroscience, 2014Co-Authors: Vassilis Cutsuridis, Veena Kumari, Ulrich EttingerAbstract:Antisaccade performance deficits in schizophrenia are generally interpreted as an impaired top–down inhibitory signal failing to suppress the erroneous response. We recorded the Antisaccade performance (error rates and latencies) of healthy and schizophrenia subjects performing the mirror Antisaccade task. A neural rise-to-threshold model of Antisaccade performance was developed to uncover the biophysical mechanisms giving rise to the observed deficits in schizophrenia. Schizophrenia patients displayed greater variability in the Antisaccade and corrected Antisaccade latency distributions, increased error rates and decreased corrected errors, relative to healthy participants. Our model showed that (1) increased variability is due to a more noisy accumulation of information by schizophrenia patients, but their confidence level required before making a decision is unaffected, and (2) competition between the correct and erroneous decision processes, and not a third top-down inhibitory signal suppressing the erroneous response, accounts for the Antisaccade performance of healthy and schizophrenia subjects. Local competition further ensured that a correct Antisaccade is never followed by an error prosaccade.
Dara S. Manoach - One of the best experts on this subject based on the ideXlab platform.
-
Abnormally persistent fMRI activation during Antisaccades in schizophrenia: a neural correlate of perseveration?
Schizophrenia Research, 2011Co-Authors: Kara A. Dyckman, Jason J. S. Barton, Yigal Agam, Mark G. Vangel, Donald C. Goff, Dara S. ManoachAbstract:article Objective: Impaired Antisaccade performance is a consistent cognitive finding in schizophrenia. Antisaccades require both response inhibition and volitional motor programming, functions that are essential to flexible responding. We investigated whether abnormal timing of hemodynamic responses (HDRs) to Antisaccades might contribute to perseveration of ocular motor responses in schizophrenia. We focused on the frontal eye field (FEF), which has been implicated in the persistent effects of Antisaccades on subsequent responses in healthy individuals. Method: Eighteen chronic, medicated schizophrenia outpatients and 15 healthy controls performed Antisaccades and prosaccades during functional MRI. Finite impulse response models provided unbiased estimates of event-related HDRs. We compared groups on the peak amplitude, time-to-peak, and full-width half-max of the HDRs. Results: In patients, HDRs in bilateral FEF were delayed and prolonged but ultimately of similar amplitude to that of controls. These abnormalities were present for Antisaccades, but not prosaccades, and were not seen in a control region. More prolonged HDRs predicted slower responses in trials that followed an Antisaccade. This suggests that persistent FEF activity following an Antisaccade contributes to inter-trial effects on latency. Conclusions: Delayed and prolonged HDRs for Antisaccades in schizophrenia suggest that the functions necessary for successful Antisaccade performance take longer to implement and are more persistent. If abnormally persistent neural responses on cognitively demanding tasks are a more general feature of schizophrenia, they may contribute to response perseveration, a classic behavioral abnormality. These findings also underscore the importance of evaluating the temporal dynamics of neural activity to understand cognitive dysfunction in schizophrenia.
-
reduced cognitive control of response inhibition by the anterior cingulate cortex in autism spectrum disorders
NeuroImage, 2010Co-Authors: Yigal Agam, Jason J. S. Barton, Robert M Joseph, Dara S. ManoachAbstract:Abstract Response inhibition, or the suppression of prepotent, but contextually inappropriate behaviors, is essential to adaptive, flexible responding. In autism spectrum disorders (ASD), difficulty inhibiting prepotent behaviors may contribute to restricted, repetitive behavior (RRB). Individuals with ASD consistently show deficient response inhibition while performing Antisaccades, which require one to inhibit the prepotent response of looking towards a suddenly appearing stimulus (i.e., a prosaccade), and to substitute a gaze in the opposite direction. Here, we used fMRI to identify the neural correlates of this deficit. We focused on two regions that are critical for saccadic inhibition: the frontal eye field (FEF), the key cortical region for generating volitional saccades, and the dorsal anterior cingulate cortex (dACC), which is thought to exert top–down control on the FEF. We also compared ASD and control groups on the functional connectivity of the dACC and FEF during saccadic performance. In the context of an increased Antisaccade error rate, ASD participants showed decreased functional connectivity of the FEF and dACC and decreased inhibition-related activation (based on the contrast of Antisaccades and prosaccades) in both regions. Decreased dACC activation correlated with a higher error rate in both groups, consistent with a role in top–down control. Within the ASD group, increased FEF activation and dACC/FEF functional connectivity were associated with more severe RRB. These findings demonstrate functional abnormalities in a circuit critical for volitional ocular motor control in ASD that may contribute to deficient response inhibition and to RRB. More generally, our findings suggest reduced cognitive control over behavior by the dACC in ASD.
-
the relation between Antisaccade errors fixation stability and prosaccade errors in schizophrenia
Experimental Brain Research, 2008Co-Authors: Donald C. Goff, Jason J. S. Barton, Manisha Pandita, Katy Thakkar, Dara S. ManoachAbstract:Whether Antisaccade errors in schizophrenia are due to defects in implementing saccadic inhibition or difficulty in generating novel responses is uncertain. We investigated whether Antisaccade errors were related to difficulty in inhibiting saccades when subjects were asked to maintain steady fixation, a situation that does not require a novel response. We examined the ocular motor data of 15 schizophrenia subjects and 16 healthy subjects. We assessed fixation in two situations: first, during the period before target onset during each saccadic trial, and second, during fixation trials that were interspersed with saccadic trials. We found that schizophrenia subjects had higher rates of fixation losses than control subjects in both situations. Second, both in healthy and schizophrenia subjects, Antisaccade error rate was positively correlated with the frequency of fixation losses in the preparatory period of saccadic trials, but not with the frequency of fixation losses during fixation trials. Third, Antisaccade errors were more likely to occur in trials with unstable fixation than in trials with stable fixation. Last, Antisaccade error rate was also correlated with prosaccade error rate. We conclude that Antisaccade errors are related to difficulties with implementing inhibitory control in the saccadic system. However, the finding of a correlation between the error rates for Antisaccades and prosaccades suggests that this is not specifically concerned with inhibiting the automatic prosaccade, but a more general deficit in implementing goal-oriented behavior.
-
neural activity is modulated by trial history a functional magnetic resonance imaging study of the effects of a previous Antisaccade
The Journal of Neuroscience, 2007Co-Authors: Dara S. Manoach, Jay A. Edelman, Katherine N Thakkar, Matthew S Cain, Frida E Polli, Bruce Fischl, Jason J. S. BartonAbstract:Saccadic latencies are influenced by what occurred during the previous trial. When the previous trial is an Antisaccade, the latencies of both prosaccades and Antisaccades are prolonged. The aim of this study was to identify neural correlates of this intertrial effect of Antisaccades. Specifically, based on both monkey electrophysiology and human neuroimaging findings, we expected trials preceded by Antisaccades to be associated with reduced frontal eye field (FEF) activity relative to those preceded by prosaccades. Twenty-one healthy participants performed pseudorandom sequences of prosaccade and Antisaccade trials during functional magnetic resonance imaging (fMRI) with concurrent monitoring of eye position. We compared activity in trials preceded by an Antisaccade with activity in trials preceded by a prosaccade. The primary result was that a previous Antisaccade prolonged saccadic latency and reduced fMRI activity in the FEF and other regions. No regions showed increased activity. We interpret the reduced FEF activity and slower saccadic responses to reflect inhibitory influences on the response system as a consequence of performing an Antisaccade in the previous trial. This demonstrates that neural activity is modulated by trial history, consistent with a rapid, dynamic form of learning. More generally, these results highlight the importance of trial history as a source of variability in both behavioral and neuroimaging studies.
-
Task-switching with Antisaccades versus no-go trials: a comparison of inter-trial effects.
Experimental Brain Research, 2005Co-Authors: Jason J. S. Barton, Mustafa Raoof, Omar Farooq Jameel, Dara S. ManoachAbstract:Antisaccades involve the suppression of a pre-potent prosaccade and a vector inversion to generate the novel ocular motor response of looking away from the target. Antisaccades have also been found to prolong the latencies of saccades in upcoming trials, an effect that we attribute to a form of immediate plasticity in the ocular motor system. Our goal was to determine whether the inter-trial effects of Antisaccades were similar to that of no-go trials, where subjects must suppress making a saccade when the target appears without substituting a novel ocular motor response. We tested 12 subjects with two different blocks of saccadic trials. In one, prosaccades randomly alternated with Antisaccades. In the other, prosaccades alternated with no-go trials. We analyzed the error rates and latencies of prosaccades that followed Antisaccades versus no-go trials, compared to repeated prosaccades, to determine if inter-trial effects were present for both types of responses that required prosaccade suppression. No-go responses increased the error rates of prosaccades in the following trial less than Antisaccades did. However, no-go trials had the same effect on the latencies of upcoming prosaccades as Antisaccades. The inhibitory effect that prolongs the latencies of prosaccades after Antisaccades likely stems from the need to inhibit a prosaccade, a function that is also required in no-go trials. The greater impairment of prosaccade accuracy after an Antisaccade may reflect either additional control mechanisms involved in vector inversion or a different form of inhibitory control that operates during Antisaccades and not during no-go responses.
Matthew Heath - One of the best experts on this subject based on the ideXlab platform.
-
No evidence supporting perceptual averaging for auditory pro- and Antisaccades
Journal of Exercise Movement and Sport, 2016Co-Authors: Jennifer Campbell, Caitlin Gillen, Matthew HeathAbstract:The visual Antisaccade task requires the top-down and two-component process of inhibiting a stimulus-driven prosaccade and the visual inversion of a target's location to mirror-symmetrical space. Notably, recent work by our group (Gillen and Heath 2014: Vis Res; Heath et al. 2015: J Vis) has shown that visual vector inversion is perception-based and governed via a statistical summary representation (SSR). In particular, showing Antisaccade – but not prosaccade – amplitudes are biased in the direction of the most frequently presented visual target within a stimulus-set. The present investigation was designed to examine whether a SSR influences auditory-based pro- and Antisaccades, and thus determine whether the SSR reflects a modality-independent or modality-dependent characteristic of Antisaccades. To that end, participants completed pro- and Antisaccades to acoustic targets (i.e., 50 ms burst, 70 dBA) in which eccentricity was defined by distinct frequency spectrums (i.e., 10.5° target = pink noise; 15.5° target = white noise; 20.5° target = blue noise). Moreover, responses were completed in separate blocks wherein each target eccentricity was presented the same number of times (i.e., control condition), and when 10.5° (i.e., proximal-weighting condition) and 20.5° (i.e., distal-weighting condition) target eccentricities were presented five times as often. As expected, prosaccades yielded shorter and more accurate endpoints than Antisaccades; however, the general difference between pro- and Antisaccades was not modulated by the different weighting conditions. Thus, auditory Antisaccades do not elicit a SSR comparable to their visual counterparts and we propose that such a result indicates that the SSR is a modality-dependent phenomenon of oculomotor control. Acknowledgments: Supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant.
-
the Antisaccade task visual distractors elicit a location independent planning cost
PLOS ONE, 2015Co-Authors: Jesse C Desimone, Stefan Everling, Matthew HeathAbstract:The presentation of a remote – but not proximal – distractor concurrent with target onset increases prosaccade reaction times (RT) (i.e., the remote distractor effect: RDE). The competitive integration model asserts that the RDE represents the time required to resolve the conflict for a common saccade threshold between target- and distractor-related saccade generating commands in the superior colliculus. To our knowledge however, no previous research has examined whether remote and proximal distractors differentially influence Antisaccade RTs. This represents a notable question because Antisaccades require decoupling of the spatial relations between stimulus and response (SR) and therefore provide a basis for determining whether the sensory- and/or motor-related features of a distractor influence response planning. Participants completed pro- and Antisaccades in a target-only condition and conditions wherein the target was concurrently presented with a proximal or remote distractor. As expected, prosaccade RTs elicited a reliable RDE. In contrast, Antisaccade RTs were increased independent of the distractor’s spatial location and the magnitude of the effect was comparable across each distractor location. Thus, distractor-related Antisaccade RT costs are not accounted for by a competitive integration between conflicting saccade generating commands. Instead, we propose that a visual distractor increases uncertainty related to the evocation of the response-selection rule necessary for decoupling SR relations.
-
Perceptual averaging for auditory pro- and Antisaccades
2015Co-Authors: Jennifer Campbell, Caitlin Gillen, Matthew HeathAbstract:The visual Antisaccade task requires the top-down and two-component processing of inhibiting a stimulus-driven prosaccade (i.e., response suppression) and the mirror-symmetrical inversion of a target's visual location (i.e., vector inversion). Notably, recent work by our group (Gillen and Heath 2014: Vis Res; Heath et al. 2015: J Vis) has shown that vector inversion is a perception-based process governed via a statistical summary representation (SSR). In particular, our work showed that Antisaccade amplitudes were biased in the direction of the most frequently presented target in a stimulus-set. The present investigation was designed to examine whether a SSR influences auditory-based pro- and Antisaccades. To that end, participants completed auditory (i.e., 50 ms burst, 70 dBA white noise) pro- and Antisaccades to three target eccentricities (10.5°, 15.5° and 20.5°) in blocks wherein eccentricities were presented with equal frequency (i.e., control-weighting condition) and when the 10.5° (i.e., proximal-weighting condition) and 20.5° (i.e., distal-weighting condition) targets were presented five times as often as the other eccentricities. Results showed that pro- and Antisaccade amplitudes were refractory to the different weighting conditions; however, the slope relating amplitude to target eccentricity was markedly shallower for the latter task (prosaccade: b=0.51; Antisaccade: b=0.17;). Thus, preliminary results provide no evidence that weighting conditions differentially influenced the specification of pro- and Antisaccade amplitudes. That said, the shallower amplitude/target eccentricity slope associated with Antisaccades provides some evidence that an auditory vector inversion process is governed via a SSR that is similar to its visually based counterpart. Acknowledgments: Supported by NSERC
-
perceptual averaging governs Antisaccade endpoint bias
Experimental Brain Research, 2014Co-Authors: Caitlin Gillen, Matthew HeathAbstract:Antisaccades entail decoupling the spatial relations between stimulus and response and executing a saccade to a target’s mirror-symmetrical location. The indirect spatial relations require that a relative target percept supports Antisaccade sensorimotor transformations. Here, we sought to identify whether the percept supporting Antisaccades results in a respective over- and undershooting bias for the near and far targets within a stimulus-set (i.e., oculomotor range effect hypothesis) or renders an eccentricity-specific bias based on a statistical summary of the individual target percepts in a stimulus-set (i.e., perceptual averaging hypothesis). Antisaccades (and complementary prosaccades) were completed in separate blocks (i.e., proximal and distal) that contained an equal number of target eccentricities, but differed with respect to their magnitudes. The proximal block included eccentricities of 3.0°, 5.5°, 8.0°, 10.5°, and 13.0°, whereas the distal block included eccentricities of 10.5°, 13.0°, 15.5°, 18.0°, and 20.5°. The proximal block showed that Antisaccade amplitudes to the central target (8.0°) did not elicit a reliable bias, whereas the block’s ‘near’ (3.0° and 5.5°) and ‘far’ (10.5° and 13.0°) targets produced an over- and undershooting bias, respectively. Notably, however, the distal block showed a reliable—and large magnitude—undershooting bias for the central target (i.e., 15.5°): a bias that generalized to each target within the block. Taken together, results for the proximal and distal blocks are incompatible with the range effect hypothesis. Instead, results indicate that the visual percept supporting Antisaccades is based on the statistical summary of the range of target eccentricities within a stimulus-set (i.e., perceptual averaging). Moreover, perceptual averaging represents a parsimonious basis by which the oculomotor system can specify sensorimotor transformations via non-veridical (i.e., relative) visual information.
-
Repetitive Antisaccade execution does not increase the unidirectional prosaccade switch-cost
Acta Psychologica, 2014Co-Authors: Jeffrey Weiler, Matthew HeathAbstract:Abstract An Antisaccade is the execution of a saccade to the mirror-symmetrical location (i.e., same amplitude but opposite visual field) of a single and exogenously presented visual target. Such a response requires top-down decoupling of the normally direct spatial relations between stimulus and response and results in increased planning times and directional errors compared to their spatially compatible prosaccade counterparts. Moreover, Antisaccades are associated with diffuse changes in cortical and subcortical saccade networks: a finding that has, in part, been attributed to pre-setting the oculomotor system to withhold a stimulus-driven prosaccade. Moreover, recent work has shown that a corollary cost of oculomotor pre-setting is that the planning time for a to-be-completed prosaccade is longer when preceded by an Antisaccade (i.e., the unidirectional prosaccade switch-cost). Notably, this result has been attributed to Antisaccades imparting a residual inhibition of the oculomotor networks that support the planning of stimulus-driven prosaccades. In the current investigation, we sought to determine if the number of Antisaccades preceding a prosaccade increases this residual inhibition and thus influences the magnitude of the unidirectional prosaccade switch-cost. To that end, participants alternated between pro- and Antisaccades after every second (i.e., AABB schedule) and every fourth (i.e., AAAABBBB schedule) trial. In addition, participants completed pro- and Antisaccades in separate blocks of trials. Results demonstrated that task-switch prosaccades produced longer reaction times than their task-repetition and blocked condition counterparts, whereas Antisaccade reaction times did not vary across task-repetition, task-switch and blocked condition trials. Most notably, the magnitude of the unidirectional prosaccade switch-cost was not modulated across the different task-switching schedules. Thus, we propose that the top-down requirements of the Antisaccade task do not produce additive inhibition of stimulus-driven saccade networks.
Stefan Everling - One of the best experts on this subject based on the ideXlab platform.
-
the Antisaccade task visual distractors elicit a location independent planning cost
PLOS ONE, 2015Co-Authors: Jesse C Desimone, Stefan Everling, Matthew HeathAbstract:The presentation of a remote – but not proximal – distractor concurrent with target onset increases prosaccade reaction times (RT) (i.e., the remote distractor effect: RDE). The competitive integration model asserts that the RDE represents the time required to resolve the conflict for a common saccade threshold between target- and distractor-related saccade generating commands in the superior colliculus. To our knowledge however, no previous research has examined whether remote and proximal distractors differentially influence Antisaccade RTs. This represents a notable question because Antisaccades require decoupling of the spatial relations between stimulus and response (SR) and therefore provide a basis for determining whether the sensory- and/or motor-related features of a distractor influence response planning. Participants completed pro- and Antisaccades in a target-only condition and conditions wherein the target was concurrently presented with a proximal or remote distractor. As expected, prosaccade RTs elicited a reliable RDE. In contrast, Antisaccade RTs were increased independent of the distractor’s spatial location and the magnitude of the effect was comparable across each distractor location. Thus, distractor-related Antisaccade RT costs are not accounted for by a competitive integration between conflicting saccade generating commands. Instead, we propose that a visual distractor increases uncertainty related to the evocation of the response-selection rule necessary for decoupling SR relations.
-
Effects of anterior cingulate microstimulation on pro-and Antisaccades in nonhuman primates
Journal of Cognitive Neuroscience, 2010Co-Authors: Jessica M. Phillips, Kevin Johnston, Stefan EverlingAbstract:Numerous studies have established a role for the ACC in cognitive control. Current theories are at odds as to whether ACC itself directly engages or alternatively recruits other frontal cortical areas that implement control. The Antisaccade task, in which subjects are required to make a saccade to the location opposite a suddenly appearing visual stimulus, is a simple oculomotor paradigm that has been used extensively to investigate flexible oculomotor control. Here, we tested a causal role of the dorsal ACC in cognitive control by applying electrical microstimulation during a preparatory period while monkeys performed alternating blocks of pro-and Antisaccade trials. Microstimulation induced significant changes in saccadic RTs (SRTs) in both tasks. On prosaccade trials, SRTs were increased for saccades contralateral to and decreased for saccades ipsilateral to the stimulated hemisphere. In contrast, SRTs were decreased for both ipsi-and contralaterally directed Antisaccades. These data show that microstimulation administered during response preparation facilitated the performance of Antisaccades and are suggestive of a direct role of ACC in the implementation of cognitive control.
-
microstimulation of monkey dorsolateral prefrontal cortex impairs Antisaccade performance
Experimental Brain Research, 2008Co-Authors: Stephen P Wegener, Stefan Everling, Kevin JohnstonAbstract:The dorsolateral prefrontal cortex (DLPFC) has been implicated in various cognitive functions, including response suppression. This function is frequently probed with the Antisaccade task, which requires suppression of the automatic tendency to look toward a flashed peripheral stimulus (prosaccade), and instead generate a voluntary saccade to the mirror location. To test whether activity in the DLPFC is causally linked to Antisaccade performance, we applied electrical microstimulation to sites in the DLPFC of two monkeys, while they performed randomly interleaved pro- and Antisaccade trials. Microstimulation resulted in significantly longer saccadic reaction times for ipsilaterally directed prosaccades and Antisaccades, and increased the error rate on ipsilateral Antisaccade trials. These findings provide causal evidence that activity in the DLPFC influences saccadic eye movements.
-
Frontoparietal activation with preparation for Antisaccades.
Journal of Neurophysiology, 2007Co-Authors: Matthew R. G. Brown, Tutis Vilis, Stefan EverlingAbstract:Several current models hold that frontoparietal areas exert cognitive control by biasing task-relevant processing in other brain areas. Previous event-related functional magnetic resonance imaging (fMRI) studies have compared prosaccades and Antisaccades, which require subjects to look toward or away from a flashed peripheral stimulus, respectively. These studies found greater activation for Antisaccades in frontal and parietal regions at the ends of long (≥6 s) preparatory periods preceding peripheral stimulus presentation. Event-related fMRI studies using short preparatory periods (≤4 s) have not found such activation differences except in the frontal eye field. Here, we identified activation differences associated with short (1-s) preparatory periods by interleaving half trials among regular whole trials in a rapid fMRI design. On whole trials, a colored fixation dot instructed human subjects to make either a prosaccade toward or an Antisaccade away from a peripheral visual stimulus. Half trials included only the instruction and not peripheral stimulus presentation or saccade generation. Nonetheless, half trials evoked stronger activation on Antisaccades than on prosaccades in the frontal eye field (FEF), supplementary eye field (SEF), left dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), intraparietal sulcus (IPS), and precuneus. Greater Antisaccade response-related activation was found in FEF, SEF, IPS, and precuneus but not in DLPFC or ACC. These results demonstrate greater preparatory activation for Antisaccades versus prosaccades in frontoparietal areas and suggest that prefrontal cortex and anterior cingulate cortex are more involved in presetting the saccade network for the Antisaccade task than generating the actual Antisaccade response.
-
Frontoparietal Activation with Preparation for Antisaccades Running Head: Rapid fMRI of Pro and Antisaccades
2007Co-Authors: Matthew Brown, Tutis Vilis, Stefan EverlingAbstract:Abstract Several current models hold that frontoparietal areas exert cognitive control by biasing task-relevant processing in other brain areas. Previous event-related functional magnetic resonance imaging (fMRI) studies have compared prosaccades and Antisaccades, which require subjects to look toward or away from a flashed peripheral stimulus, respectively. These studies found greater activation for Antisaccades in frontal and parietal regions at the ends of long ( 6s) preparatory periods preceding peripheral stimulus presentation. Event-related fMRI studies using short preparatory periods ( 4s) have not found such activation differences except in frontal eye field. Here, we identified activation differences associated with short (1s) preparatory periods by interleaving half trials among regular whole trials in a rapid fMRI design. On whole trials, a coloured fixation dot instructed human subjects either to make a prosaccade toward or an Antisaccade away from a peripheral visual stimulus. Half trials included only the instruction and not peripheral stimulus presentation or saccade generation. None-the-less, half trials evoked stronger activation on Antisaccades than prosaccades in the frontal eye field (FEF), supplementary eye field (SEF), left dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), intraparietal sulcus (IPS), and precuneus. Greater Antisaccade response-related activation was found in FEF, SEF, IPS, and precuneus but not in DLPFC or ACC. These results demonstrate greater preparatory activation for Antisaccades versus prosaccades in frontoparietal areas and suggest that prefrontal cortex and anterior cingulate cortex are more involved in presetting the saccade network for the Antisaccade task than generating the actual Antisaccade response.Keywords: saccades, fMRI, deconvolution, rapid event-related, catch trial, half trial