scholarly journals Single unit activity in marmoset posterior parietal cortex in a gap saccade task

2019 ◽  
Author(s):  
Liya Ma ◽  
Janahan Selvanayagam ◽  
Maryam Ghahremani ◽  
Lauren K. Hayrynen ◽  
Kevin D. Johnston ◽  
...  
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Reaction Times ◽  
Saccadic Eye Movements ◽  
Neuronal Population ◽  
Single Unit Activity ◽  
Cortical Control ◽  
Posterior Parietal ◽  
Saccadic Reaction Times

ABSTRACTAbnormal saccadic eye movements can serve as biomarkers for patients with several neuropsychiatric disorders. To investigate cortical control mechanisms of saccadic responses, the common marmoset (Callithrix jacchus) is a promising non-human primate model. Their lissencephalic brain allows for accurate targeting of homologues of sulcal areas in the macaque brain. Here we recorded single unit activity in the posterior parietal cortex of two marmosets using chronic microelectrode arrays, while the monkeys performed a saccadic task with Gap trials (stimulus onset lagged fixation point offset by 200ms) interleaved with Step trials (fixation point disappeared when the peripheral stimulus appeared). Both marmosets showed a gap effect—shorter saccadic reaction times (SRTs) in Gap vs. Step trials. On average, stronger gap-period response across the entire neuronal population preceded shorter SRTs on trials with contralateral targets, although this correlation was stronger among the 15% ‘gap neurons’, which responded significantly during the gap. We also found 39% ‘target neurons’ with significant visual target-related responses, which were stronger in Gap trials and correlated with the SRTs better than the remaining cells. Compared with slow saccades, fast saccades were preceded by both stronger gap-related and target-related response in all PPC neurons, regardless of whether such response reached significance. Our findings suggest that the PPC in the marmoset contains an area that is involved in the modulation of saccadic preparation and plays roles comparable to those of area LIP in macaque monkeys in eye movements.SIGNIFICANCE STATEMENTAbnormal saccadic eye movements can serve as biomarkers for different neuropsychiatric disorders. So far, processes of cerebral cortical control of saccades are not fully understood. Non-human primates are ideal models for studying such processes, and the marmoset is especially advantageous since their smooth cortex permits laminar analyses of cortical microcircuits. Using electrode arrays implanted in the posterior parietal cortex of marmosets, we found neurons responsive to key periods of a saccadic task in a manner that contribute to cortical modulation of saccadic preparation. Notably, this signal was correlated with subsequent saccadic reaction times and was present in the entire neuronal population. We suggest that the marmoset model will shed new light on the cortical mechanisms of saccadic control.

The encoding of saccadic eye movements within human posterior parietal cortex

NeuroImage ◽  
2004 ◽  
Vol 22 (1) ◽  
pp. 304-314 ◽  
Author(s):  
Christina S Konen ◽  
Raimund Kleiser ◽  
Hans-Jörg Wittsack ◽  
Frank Bremmer ◽  
Rüdiger J Seitz
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Saccadic Eye Movements ◽  
Posterior Parietal

scholarly journals Visual-Manual Exploration and Posterior Parietal Cortex in Humans

2009 ◽  
Vol 102 (6) ◽  
pp. 3433-3446 ◽  
Author(s):  
Leighton B. N. Hinkley ◽  
Leah A. Krubitzer ◽  
Jeff Padberg ◽  
Elizabeth A. Disbrow
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Right Hemisphere ◽  
Motor Behavior ◽  
Saccadic Eye Movements ◽  
Cortical Activation ◽  
Visually Guided ◽  
Visually Guided Reaching ◽  
Posterior Parietal

Areas of human posterior parietal cortex (PPC) specialized for processing sensorimotor information associated with visually locating an object, reaching to grasp, and manually exploring that object were examined using functional MRI. Cortical activation was observed in response to three tasks: 1) saccadic eye movements, 2) visually guided reaching to grasp, and 3) manual shape discrimination. During saccadic eye movements, cortical fields within the lateral and rostral superior parietal lobe (SPL) and the caudal SPL and parieto-occipital boundary were active. During visually guided reaching to grasp, regions of cortex within the postcentral sulcus (PoCS) and rostral intraparietal sulcus (IPS) were active, as well as the caudal SPL of the left hemisphere and the medial and caudal IPS of the right hemisphere. Cortical regions at the junction of the IPS and PoCS and an area in the medial SPL were active bilaterally during shape manipulation. Only a few regions were most active during a single motor behavior, whereas several areas were highly active during two or more tasks. Hemispheric asymmetries in activation patterns were observed during visually guided reaching to grasp. The gross areal organization of human PPC is likely similar to the pattern previously described in nonhuman primates, including multifunctional regions and asymmetric processing of some manual abilities.

scholarly journals Electrical microstimulation evokes saccades in posterior parietal cortex of common marmosets

2019 ◽  
Vol 122 (4) ◽  
pp. 1765-1776 ◽  
Author(s):  
Maryam Ghahremani ◽  
Kevin D. Johnston ◽  
Liya Ma ◽  
Lauren K. Hayrynen ◽  
Stefan Everling
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Common Marmoset ◽  
Primate Species ◽  
Oculomotor Control ◽  
Electrical Microstimulation ◽  
Cortical Areas ◽  
Posterior Parietal ◽  
The Common

The common marmoset ( Callithrix jacchus) is a small-bodied New World primate increasing in prominence as a model animal for neuroscience research. The lissencephalic cortex of this primate species provides substantial advantages for the application of electrophysiological techniques such as high-density and laminar recordings, which have the capacity to advance our understanding of local and laminar cortical circuits and their roles in cognitive and motor functions. This is particularly the case with respect to the oculomotor system, as critical cortical areas of this network such as the frontal eye fields (FEF) and lateral intraparietal area (LIP) lie deep within sulci in macaques. Studies of cytoarchitecture and connectivity have established putative homologies between cortical oculomotor fields in marmoset and macaque, but physiological investigations of these areas, particularly in awake marmosets, have yet to be carried out. Here we addressed this gap by probing the function of posterior parietal cortex of the common marmoset with electrical microstimulation. We implanted two animals with 32-channel Utah arrays at the location of the putative area LIP and applied microstimulation while they viewed a video display and made untrained eye movements. Similar to previous studies in macaques, stimulation evoked fixed-vector and goal-directed saccades, staircase saccades, and eyeblinks. These data demonstrate that area LIP of the marmoset plays a role in the regulation of eye movements, provide additional evidence that this area is homologous with that of the macaque, and further establish the marmoset as a valuable model for neurophysiological investigations of oculomotor and cognitive control. NEW & NOTEWORTHY The macaque monkey has been the preeminent model for investigations of oculomotor control, but studies of cortical areas are limited, as many of these areas are buried within sulci in this species. Here we applied electrical microstimulation to the putative area LIP of the lissencephalic cortex of awake marmosets. Similar to the macaque, microstimulation evoked contralateral saccades from this area, supporting the marmoset as a valuable model for studies of oculomotor control.

Audiovisual stimulus-driven contributions to spatial orienting in ecologically valid situations: An fMRI study

2012 ◽  
Vol 25 (0) ◽  
pp. 16
Author(s):  
Davide Nardo ◽  
Valerio Santangelo ◽  
Emiliano Macaluso
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Computational Models ◽  
Spatial Relationship ◽  
Visual Saliency ◽  
Occipital Cortex ◽  
Audiovisual Stimulus ◽  
Spatial Orienting ◽  
Posterior Parietal

Mechanisms of audiovisual attention have been extensively investigated, yet little is known about their functioning in ecologically-valid situations. Here, we investigated brain activity associated with audiovisual stimulus-driven attention using naturalistic stimuli. We created 120 short videos (2.5 s) showing scenes of everyday life. Each video included a visual event comprising a lateralized (left/right) increase in visual saliency (e.g., an actor moving an object), plus a co-occurring sound either on the same or the opposite side of space. Subjects viewed the videos with/without the associated sounds, and either in covert (central fixation) or overt (eye-movements allowed) viewing conditions. For each stimulus, we used computational models (‘saliency maps’) to characterize auditory and visual stimulus-driven signals, and eye-movements (recorded in free viewing) as a measure of the efficacy of these signals for spatial orienting. Results showed that visual saliency modulated activity in the occipital cortex contralateral to the visual event; while auditory saliency modulated activity in the superior temporal gyrus bilaterally. In the posterior parietal cortex activity increased with increasing auditory saliency, but only when the auditory stimulus was on the same side as the visual event. The efficacy of the stimulus-driven signals modulated activity in the visual cortex. We conclude that: (1) audiovisual attention can be successfully investigated in real-like situations; (2) activity in sensory areas reflects a combination of stimulus-driven signals (saliency) and their efficacy for spatial orienting; (3) posterior parietal cortex processes auditory input as a function of its spatial relationship with the visual input.

scholarly journals Saccades, attentional orienting and disengagement: the effects of anodal tDCS over right posterior parietal cortex (PPC) and frontal eye field (FEF)

2021 ◽  
Author(s):  
Lorenzo Diana ◽  
Patrick Pilastro ◽  
Edoardo N. Aiello ◽  
Aleksandra K. Eberhard-Moscicka ◽  
René M. Müri ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Right Hemisphere ◽  
Reaction Times ◽  
Gap Effect ◽  
Frontal Eye Field ◽  
Attentional Orienting ◽  
Eye Field ◽  
Posterior Parietal ◽  
The Right

ABSTRACTIn the present work, we applied anodal transcranial direct current stimulation (tDCS) over the posterior parietal cortex (PPC) and frontal eye field (FEF) of the right hemisphere in healthy subjects to modulate attentional orienting and disengagement in a gap-overlap task. Both stimulations led to bilateral improvements in saccadic reaction times (SRTs), with larger effects for gap trials. However, analyses showed that the gap effect was not affected by tDCS. Importantly, we observed significant effects of baseline performance that may mediate side- and task-specific effects of brain stimulation.

scholarly journals Single-unit activity in marmoset posterior parietal cortex in a gap saccade task

2020 ◽  
Vol 123 (3) ◽  
pp. 896-911 ◽  
Author(s):  
Liya Ma ◽  
Janahan Selvanayagam ◽  
Maryam Ghahremani ◽  
Lauren K. Hayrynen ◽  
Kevin D. Johnston ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Unit Activity ◽  
Single Unit ◽  
Posterior Parietal Cortex ◽  
Common Marmoset ◽  
Gap Effect ◽  
Oculomotor Control ◽  
Single Unit Activity ◽  
Primate Model ◽  
Posterior Parietal

Abnormal saccadic eye movements can serve as biomarkers for patients with several neuropsychiatric disorders. The common marmoset ( Callithrix jacchus) is becoming increasingly popular as a nonhuman primate model to investigate the cortical mechanisms of saccadic control. Recently, our group demonstrated that microstimulation in the posterior parietal cortex (PPC) of marmosets elicits contralateral saccades. Here we recorded single-unit activity in the PPC of the same two marmosets using chronic microelectrode arrays while the monkeys performed a saccadic task with gap trials (target onset lagged fixation point offset by 200 ms) interleaved with step trials (fixation point disappeared when the peripheral target appeared). Both marmosets showed a gap effect, shorter saccadic reaction times (SRTs) in gap vs. step trials. On average, stronger gap-period responses across the entire neuronal population preceded shorter SRTs on trials with contralateral targets although this correlation was stronger among the 15% “gap neurons,” which responded significantly during the gap. We also found 39% “target neurons” with significant saccadic target-related responses, which were stronger in gap trials and correlated with the SRTs better than the remaining neurons. Compared with saccades with relatively long SRTs, short-SRT saccades were preceded by both stronger gap-related and target-related responses in all PPC neurons, regardless of whether such response reached significance. Our findings suggest that the PPC in the marmoset contains an area that is involved in the modulation of saccadic preparation. NEW & NOTEWORTHY As a primate model in systems neuroscience, the marmoset is a great complement to the macaque monkey because of its unique advantages. To identify oculomotor networks in the marmoset, we recorded from the marmoset posterior parietal cortex during a saccadic task and found single-unit activities consistent with a role in saccadic modulation. This finding supports the marmoset as a valuable model for studying oculomotor control.

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