Changes in Effective Connectivity of the Superior Parietal Lobe during Inhibition and Redirection of Eye Movements

Journal of Experimental Neuroscience ◽

10.4137/jen.s32736 ◽

2015 ◽

Vol 9s1 ◽

pp. JEN.S32736

Author(s):

Susanne J. Asscheman ◽

Katharine N. Thakkar ◽

Sebastiaan F.W. Neggers

Keyword(s):

Eye Movements ◽

Executive Control ◽

Parietal Lobe ◽

Effective Connectivity ◽

Saccadic Eye Movements ◽

Brain Regions ◽

Anterior Cingulate ◽

Imaging Data ◽

Saccade Control

Executive control is the ability to flexibly control behavior and is frequently studied with saccadic eye movements. Contrary to frontal oculomotor areas, the role of the superior parietal lobe (SPL) in the executive control of saccades remains unknown. To explore the role of SPL networks in saccade control, we performed a saccadic search-step task while acquiring functional magnetic resonance imaging data for 41 participants. Psychophysiological interaction analyses assessed task-related differences in the effective connectivity of SPL with other brain regions during the inhibition and redirection of saccades. Results indicate an increased coupling of SPL with frontal, posterior, and striatal oculomotor areas for redirected saccades versus visually guided saccades. Saccade inhibition versus unsuccessful inhibition revealed an increased coupling of SPL with dorsolateral prefrontal cortex and anterior cingulate cortex. We discuss how these findings relate to ongoing debates about the implementation of executive control and conclude that early attentional control and rapid updating of saccade goals are important signals for executive control.

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Faculty Opinions recommendation of Head-free gaze shifts provide further insights into the role of the medial cerebellum in the control of primate saccadic eye movements.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.4961957.4893055 ◽

2010 ◽

Author(s):

Raj Gandhi

Keyword(s):

Eye Movements ◽

Saccadic Eye Movements ◽

Gaze Shifts

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Effects of unilateral deactivations of dorsolateral prefrontal cortex and anterior cingulate cortex on saccadic eye movements

Journal of Neurophysiology ◽

10.1152/jn.00626.2013 ◽

2014 ◽

Vol 111 (4) ◽

pp. 787-803 ◽

Cited By ~ 12

Author(s):

Michael J. Koval ◽

R. Matthew Hutchison ◽

Stephen G. Lomber ◽

Stefan Everling

Keyword(s):

Prefrontal Cortex ◽

Eye Movements ◽

Functional Connectivity ◽

Anterior Cingulate Cortex ◽

Dorsolateral Prefrontal Cortex ◽

Saccadic Eye Movements ◽

Cingulate Cortex ◽

Anterior Cingulate ◽

Dorsolateral Prefrontal ◽

Single Neuron Recording

The dorsolateral prefrontal cortex (dlPFC) and anterior cingulate cortex (ACC) have both been implicated in the cognitive control of saccadic eye movements by single neuron recording studies in nonhuman primates and functional imaging studies in humans, but their relative roles remain unclear. Here, we reversibly deactivated either dlPFC or ACC subregions in macaque monkeys while the animals performed randomly interleaved pro- and antisaccades. In addition, we explored the whole-brain functional connectivity of these two regions by applying a seed-based resting-state functional MRI analysis in a separate cohort of monkeys. We found that unilateral dlPFC deactivation had stronger behavioral effects on saccades than unilateral ACC deactivation, and that the dlPFC displayed stronger functional connectivity with frontoparietal areas than the ACC. We suggest that the dlPFC plays a more prominent role in the preparation of pro- and antisaccades than the ACC.

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Framing and Self-Responsibility Modulate Brain Activities in Decision Escalation

10.21203/rs.2.24818/v4 ◽

2021 ◽

Author(s):

Ting-Peng Liang ◽

Yuwen Li ◽

Nai-Shing Yen ◽

Ofir Turel ◽

Sen-Mou Hsu

Keyword(s):

Anterior Cingulate Cortex ◽

Contextual Factors ◽

Inferior Frontal Gyrus ◽

Cingulate Cortex ◽

Brain Regions ◽

Anterior Cingulate ◽

Imaging Data ◽

Two Factors ◽

Human Decision

Abstract Background: Escalation of commitment is a common bias in human decision making. The present study examined (1) differences in neural recruitment for escalation and de-escalation decisions of prior investments, and (2) how the activations of these brain networks are modulated by two factors that are often argued to modulate the behavior: (i) self-responsibility, and (ii) framing of the success probabilities. Results: Imaging data were obtained from functional magnetic resonance imaging (fMRI) applied to 29 participants. A whole-brain analysis was conducted to compare brain activations between conditions. ROI analysis, then, was used to examine if these significant activations were modulated by two contextual factors. Finally, mediation analysis was applied to explore how the contextual factors affect escalation decisions through brain activations. The findings showed that (1) escalation decisions are faster than de-escalation decisions, (2) the corresponding network of brain regions recruited for escalation (anterior cingulate cortex, insula and precuneus) decisions differs from this recruited for de-escalation decisions (inferior and superior frontal gyri), (3) the switch from escalation to de-escalation is primarily frontal gyri dependent, and (4) activation in the anterior cingulate cortex, insula and precuneus were further increased in escalation decisions, when the outcome probabilities of the follow-up investment were positively framed; and activation in the inferior and superior frontal gyri in de-escalation decisions were increased when the outcome probabilities were negatively framed. Conclusions: Escalation and de-escalation decisions recruit different brain regions. Framing of possible outcomes as negative leads to escalation decisions through recruitment of the inferior frontal gyrus. Responsibility for decisions affects escalation decisions through recruitment of the superior (inferior) gyrus, when the decision is framed positively (negatively).

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The role of action intentionality and effector in the subjective expansion of temporal duration after saccadic eye movements

Scientific Reports ◽

10.1038/s41598-020-73830-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

David Melcher ◽

Devpriya Kumar ◽

Narayanan Srinivasan

Keyword(s):

Eye Movements ◽

Visual Processing ◽

Saccadic Eye Movements ◽

Intentional Binding ◽

Opposite Pattern ◽

Motor Action ◽

Saccade Onset ◽

Backward Shift ◽

The Moment

Abstract Visual perception is based on periods of stable fixation separated by saccadic eye movements. Although naive perception seems stable (in space) and continuous (in time), laboratory studies have demonstrated that events presented around the time of saccades are misperceived spatially and temporally. Saccadic chronostasis, the “stopped clock illusion”, represents one such temporal distortion in which the movement of the clock hand after the saccade is perceived as lasting longer than usual. Multiple explanations for chronostasis have been proposed including action-backdating, temporal binding of the action towards the moment of its effect (“intentional binding”) and post-saccadic temporal dilation. The current study aimed to resolve this debate by using different types of action (keypress vs saccade) and varying the intentionality of the action. We measured both perceived onset of the motor action and perceived onset of an auditory tone presented at different delays after the keypress/saccade. The results showed intentional binding for the keypress action, with perceived motor onset shifted forwards in time and the time of the tone shifted backwards. Saccades resulted in the opposite pattern, showing temporal expansion rather than compression, especially with cued saccades. The temporal illusion was modulated by intentionality of the movement. Our findings suggest that saccadic chronostasis is not solely dependent on a backward shift in perceived saccade onset, but instead reflects a temporal dilation. This percept of an effectively “longer” period at the beginning of a new fixation may reflect the pattern of suppressed, and then enhanced, visual processing around the time of saccades.

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The role of fixation disengagement in the parallel programming of sequences of saccades

Experimental Brain Research ◽

10.1007/s00221-019-05641-9 ◽

2019 ◽

Vol 237 (11) ◽

pp. 3033-3045

Author(s):

Eugene McSorley ◽

Iain D. Gilchrist ◽

Rachel McCloy

Keyword(s):

Eye Movements ◽

Parallel Programming ◽

Response Times ◽

Saccadic Eye Movements ◽

Gap Effect ◽

Task Completion ◽

Published Data ◽

Trial Duration ◽

Visual Tasks

Abstract One of the core mechanisms involved in the control of saccade responses to selected target stimuli is the disengagement from the current fixation location, so that the next saccade can be executed. To carry out everyday visual tasks, we make multiple eye movements that can be programmed in parallel. However, the role of disengagement in the parallel programming of saccades has not been examined. It is well established that the need for disengagement slows down saccadic response time. This may be important in allowing the system to program accurate eye movements and have a role to play in the control of multiple eye movements but as yet this remains untested. Here, we report two experiments that seek to examine whether fixation disengagement reduces saccade latencies when the task completion demands multiple saccade responses. A saccade contingent paradigm was employed and participants were asked to execute saccadic eye movements to a series of seven targets while manipulating when these targets were shown. This both promotes fixation disengagement and controls the extent that parallel programming can occur. We found that trial duration decreased as more targets were made available prior to fixation: this was a result both of a reduction in the number of saccades being executed and in their saccade latencies. This supports the view that even when fixation disengagement is not required, parallel programming of multiple sequential saccadic eye movements is still present. By comparison with previous published data, we demonstrate a substantial speeded of response times in these condition (“a gap effect”) and that parallel programming is attenuated in these conditions.

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Connectivity-Related Roles of Contralesional Brain Regions for Motor Performance Early after Stroke

Cerebral Cortex ◽

10.1093/cercor/bhaa270 ◽

2020 ◽

Author(s):

Lukas Hensel ◽

Caroline Tscherpel ◽

Jana Freytag ◽

Stella Ritter ◽

Anne K Rehme ◽

...

Keyword(s):

Neural Activity ◽

Motor Performance ◽

Primary Motor Cortex ◽

Effective Connectivity ◽

Premotor Cortex ◽

Brain Regions ◽

Functional Magnetic Resonance ◽

Resonance Imaging ◽

Anterior Intraparietal Sulcus

Abstract Hemiparesis after stroke is associated with increased neural activity not only in the lesioned but also in the contralesional hemisphere. While most studies have focused on the role of contralesional primary motor cortex (M1) activity for motor performance, data on other areas within the unaffected hemisphere are scarce, especially early after stroke. We here combined functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) to elucidate the contribution of contralesional M1, dorsal premotor cortex (dPMC), and anterior intraparietal sulcus (aIPS) for the stroke-affected hand within the first 10 days after stroke. We used “online” TMS to interfere with neural activity at subject-specific fMRI coordinates while recording 3D movement kinematics. Interfering with aIPS activity improved tapping performance in patients, but not healthy controls, suggesting a maladaptive role of this region early poststroke. Analyzing effective connectivity parameters using a Lasso prediction model revealed that behavioral TMS effects were predicted by the coupling of the stimulated aIPS with dPMC and ipsilesional M1. In conclusion, we found a strong link between patterns of frontoparietal connectivity and TMS effects, indicating a detrimental influence of the contralesional aIPS on motor performance early after stroke.

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On the role of the corpus callosum in interhemispheric functional connectivity in humans

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1707050114 ◽

2017 ◽

Vol 114 (50) ◽

pp. 13278-13283 ◽

Cited By ~ 68

Author(s):

Jarod L. Roland ◽

Abraham Z. Snyder ◽

Carl D. Hacker ◽

Anish Mitra ◽

Joshua S. Shimony ◽

...

Keyword(s):

Functional Connectivity ◽

Corpus Callosum ◽

Parietal Lobe ◽

Brain Regions ◽

Resting State Functional Connectivity ◽

Limited Sample ◽

Temporal Correlations ◽

Before And After

Resting state functional connectivity is defined in terms of temporal correlations between physiologic signals, most commonly studied using functional magnetic resonance imaging. Major features of functional connectivity correspond to structural (axonal) connectivity. However, this relation is not one-to-one. Interhemispheric functional connectivity in relation to the corpus callosum presents a case in point. Specifically, several reports have documented nearly intact interhemispheric functional connectivity in individuals in whom the corpus callosum (the major commissure between the hemispheres) never develops. To investigate this question, we assessed functional connectivity before and after surgical section of the corpus callosum in 22 patients with medically refractory epilepsy. Section of the corpus callosum markedly reduced interhemispheric functional connectivity. This effect was more profound in multimodal associative areas in the frontal and parietal lobe than primary regions of sensorimotor and visual function. Moreover, no evidence of recovery was observed in a limited sample in which multiyear, longitudinal follow-up was obtained. Comparison of partial vs. complete callosotomy revealed several effects implying the existence of polysynaptic functional connectivity between remote brain regions. Thus, our results demonstrate that callosal as well as extracallosal anatomical connections play a role in the maintenance of interhemispheric functional connectivity.

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Brain glutamate in medication-free depressed patients: a proton MRS study at 7 Tesla

Psychological Medicine ◽

10.1017/s0033291717003373 ◽

2017 ◽

Vol 48 (10) ◽

pp. 1731-1737 ◽

Cited By ~ 10

Author(s):

Beata R. Godlewska ◽

Charles Masaki ◽

Ann L. Sharpley ◽

Philip J. Cowen ◽

Uzay E. Emir

Keyword(s):

Basal Ganglia ◽

Occipital Cortex ◽

Brain Regions ◽

Anterior Cingulate ◽

7 Tesla ◽

Resonance Spectroscopy ◽

Depressed Patients ◽

Water Signal ◽

Significant Difference

BackgroundThe possible role of glutamate in the pathophysiology and treatment of depression is of intense current interest. Proton magnetic resonance spectroscopy (MRS) enables the detection of glutamate in the living human brain and meta-analyses of previous MRS studies in depressed patients have suggested that glutamate levels are decreased in anterior brain regions. Nevertheless, at conventional magnetic field strengths [1.5–3 Tesla (T)], it is difficult to separate glutamate from its metabolite and precursor, glutamine, with the two often being measured together as Glx. In contrast, MRS at 7 T allows clear spectral resolution of glutamate and glutamine.MethodWe studied 55 un-medicated depressed patients and 50 healthy controls who underwent MRS scanning at 7 T with voxels placed in anterior cingulate cortex, occipital cortex and putamen (PUT). Neurometabolites were calculated using the unsuppressed water signal as a reference.ResultsCompared with controls, depressed patients showed no significant difference in glutamate in any of the three voxels studied; however, glutamine concentrations in the patients were elevated by about 12% in the PUT (p < 0.001).ConclusionsThe increase in glutamine in PUT is of interest in view of the postulated role of the basal ganglia in the neuropsychology of depression and is consistent with elevated activity in the descending cortical glutamatergic innervation to the PUT. The basal ganglia have rarely been the subject of MRS investigations in depressed patients and further MRS studies of these structures in depression are warranted.

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