The Experts below are selected from a list of 13686 Experts worldwide ranked by ideXlab platform
Adam Sachs - One of the best experts on this subject based on the ideXlab platform.
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a normalization circuit underlying coding of spatial attention in primate Lateral Prefrontal Cortex
eNeuro, 2019Co-Authors: Florian Pieper, Matthew Leavitt, Adam Sachs, Lyndon Duong, Julio MartineztrujilloAbstract:Lateral Prefrontal Cortex (LPFC) neurons signal the allocation of voluntary attention; however, the neural computations underlying this function remain unknown. To investigate this, we recorded from neuronal ensembles in the LPFC of two Macaca fascicularis performing a visuospatial attention task. LPFC neural responses to a single stimulus were normalized when additional stimuli/distracters appeared across the visual field and were well-characterized by an averaging computation. Deploying attention toward an individual stimulus surrounded by distracters shifted neural activity from an averaging regime toward a regime similar to that when the attended stimulus was presented in isolation (winner-take-all; WTA). However, attentional modulation is both qualitatively and quantitatively dependent on a neuron's visuospatial tuning. Our results show that during attentive vision, LPFC neuronal ensemble activity can be robustly read out by downstream areas to generate motor commands, and/or fed back into sensory areas to filter out distracter signals in favor of target signals.
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single trial decoding of intended eye movement goals from Lateral Prefrontal Cortex neural ensembles
Journal of Neurophysiology, 2016Co-Authors: Chadwick Boulay, Florian Pieper, Matthew Leavitt, Julio C Martineztrujillo, Adam SachsAbstract:Neurons in the Lateral Prefrontal Cortex (LPFC) encode sensory and cognitive signals, as well as commands for goal-directed actions. Therefore, the LPFC might be a good signal source for a goal-sel...
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Single-Trial Decoding of Visual Attention from Local Field Potentials in the Primate Lateral Prefrontal Cortex Is Frequency-Dependent
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2015Co-Authors: Sébastien Tremblay, Florian Pieper, Adam Sachs, Guillaume Doucet, Julio Martinez-trujilloAbstract:Local field potentials (LFPs) are fluctuations of extracellular voltage that may reflect the physiological phenomena occurring within a volume of neural tissue. It is known that the allocation of spatial attention modulates the amplitude of LFPs in visual areas of primates. An issue that remains poorly investigated is whether and how attention modulates LFPs in executive brain areas, such as the Lateral Prefrontal Cortex (LPFC), thought to be involved in the origins of attention. We addressed this issue by recording LFPs from multielectrode arrays implanted in the LPFC of two macaques. We found that the allocation of attention can be reliably decoded on a single-trial basis from ensembles of LFPs with frequencies >60 Hz. Using LFP frequencies
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Attentional filtering of visual information by neuronal ensembles in the primate Lateral Prefrontal Cortex.
Neuron, 2014Co-Authors: Sébastien Tremblay, Florian Pieper, Adam Sachs, Julio Martinez-trujilloAbstract:The activity of neurons in the primate Lateral Prefrontal Cortex (LPFC) is strongly modulated by visual attention. Such a modulation has mostly been documented by averaging the activity of independently recorded neurons over repeated experimental trials. However, in realistic settings, ensembles of simultaneously active LPFC neurons must generate attentional signals on a single-trial basis, despite the individual and correlated variability of neuronal responses. Whether, under these circumstances, the LPFC can reliably generate attentional signals is unclear. Here, we show that the simultaneous activity of neuronal ensembles in the primate LPFC can be reliably decoded to predict the allocation of attention on a single-trial basis. Decoding was sensitive to the noise correlation structure of the ensembles. Additionally, it was resilient to distractors, predictive of behavior, and stable over weeks. Thus, LPFC neuronal ensemble activity can reliably encode attention within behavioral time frames, despite the noisy and correlated nature of neuronal activity.
Julio Martinez-trujillo - One of the best experts on this subject based on the ideXlab platform.
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Dissecting Modulatory Effects of Visual Attention in Primate Lateral Prefrontal Cortex Using Signal Detection Theory
Neuron, 2018Co-Authors: Julio Martinez-trujillo, Roberto A. GulliAbstract:In this issue of Neuron, Luo and Maunsell (2018) use signal detection theory to demonstrate that the modulatory effects of attention on neuronal responses in the Lateral Prefrontal Cortex during change detection can be due to changes in an observer's sensitivity or shifts in their response criterion.
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Neuronal population coding of perceived and memorized visual features in the Lateral Prefrontal Cortex.
Nature communications, 2017Co-Authors: Diego Mendoza-halliday, Julio Martinez-trujilloAbstract:The primate Lateral Prefrontal Cortex (LPFC) encodes visual stimulus features while they are perceived and while they are maintained in working memory. However, it remains unclear whether perceived and memorized features are encoded by the same or different neurons and population activity patterns. Here we record LPFC neuronal activity while monkeys perceive the motion direction of a stimulus that remains visually available, or memorize the direction if the stimulus disappears. We find neurons with a wide variety of combinations of coding strength for perceived and memorized directions: some neurons encode both to similar degrees while others preferentially or exclusively encode either one. Reading out the combined activity of all neurons, a machine-learning algorithm reliably decode the motion direction and determine whether it is perceived or memorized. Our results indicate that a functionally diverse population of LPFC neurons provides a substrate for discriminating between perceptual and mnemonic representations of visual features. Neurons in the Lateral Prefrontal Cortex are known to encode visual features as well as maintain them in working memory. Here the authors report that LPFC neurons encode both perceived and memorized visual features in diverse combinations and the population activity reliably decodes as well as differentiates between these two representations.
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Single-Trial Decoding of Visual Attention from Local Field Potentials in the Primate Lateral Prefrontal Cortex Is Frequency-Dependent
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2015Co-Authors: Sébastien Tremblay, Florian Pieper, Adam Sachs, Guillaume Doucet, Julio Martinez-trujilloAbstract:Local field potentials (LFPs) are fluctuations of extracellular voltage that may reflect the physiological phenomena occurring within a volume of neural tissue. It is known that the allocation of spatial attention modulates the amplitude of LFPs in visual areas of primates. An issue that remains poorly investigated is whether and how attention modulates LFPs in executive brain areas, such as the Lateral Prefrontal Cortex (LPFC), thought to be involved in the origins of attention. We addressed this issue by recording LFPs from multielectrode arrays implanted in the LPFC of two macaques. We found that the allocation of attention can be reliably decoded on a single-trial basis from ensembles of LFPs with frequencies >60 Hz. Using LFP frequencies
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Attentional filtering of visual information by neuronal ensembles in the primate Lateral Prefrontal Cortex.
Neuron, 2014Co-Authors: Sébastien Tremblay, Florian Pieper, Adam Sachs, Julio Martinez-trujilloAbstract:The activity of neurons in the primate Lateral Prefrontal Cortex (LPFC) is strongly modulated by visual attention. Such a modulation has mostly been documented by averaging the activity of independently recorded neurons over repeated experimental trials. However, in realistic settings, ensembles of simultaneously active LPFC neurons must generate attentional signals on a single-trial basis, despite the individual and correlated variability of neuronal responses. Whether, under these circumstances, the LPFC can reliably generate attentional signals is unclear. Here, we show that the simultaneous activity of neuronal ensembles in the primate LPFC can be reliably decoded to predict the allocation of attention on a single-trial basis. Decoding was sensitive to the noise correlation structure of the ensembles. Additionally, it was resilient to distractors, predictive of behavior, and stable over weeks. Thus, LPFC neuronal ensemble activity can reliably encode attention within behavioral time frames, despite the noisy and correlated nature of neuronal activity.
Jun Tanji - One of the best experts on this subject based on the ideXlab platform.
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Development of Multidimensional Representations of Task Phases in the Lateral Prefrontal Cortex
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2011Co-Authors: Yosuke Saga, Jun Tanji, Michiyo Iba, Eiji HoshiAbstract:The temporal structuring of multiple events is essential for the purposeful regulation of behavior. We investigated the role of the Lateral Prefrontal Cortex (LPFC) in transforming external signals of multiple sensory modalities into information suitable for monitoring successive events across behavioral phases until an intended action is prompted and then initiated. We trained monkeys to receive a succession of 1 s visual, auditory, or tactile sensory signals separated by variable intervals and to then release a key as soon as the fourth signal appeared. Thus, the animals had to monitor and update information about the progress of the task upon receiving each signal preceding the key release in response to the fourth signal. We found that the initial, short-latency responses of LPFC neurons reflected primarily the sensory modality, rather than the phase or progress of the task. However, a task phase-selective response developed within 500 ms of signal reception, and information about the task phase was maintained throughout the presentation of successive cues. The task phase-selective activity was updated with the appearance of each cue until the planned action was initiated. The phase-selective activity of individual neurons reflected not merely a particular phase of the task but also multiple successive phases. Furthermore, we found combined representations of task phase and sensory modality in the activity of individual LPFC neurons. These properties suggest how information representing multiple phases of behavioral events develops in the LPFC to provide a basis for the temporal regulation of behavior.
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Role of the Lateral Prefrontal Cortex in Executive Behavioral Control
Physiological reviews, 2008Co-Authors: Jun Tanji, Eiji HoshiAbstract:The Lateral Prefrontal Cortex is critically involved in broad aspects of executive behavioral control. Early studies emphasized its role in the short-term retention of information retrieved from cortical association areas and in the inhibition of prepotent responses. Recent studies of subhuman primates and humans have revealed the role of this area in more general aspects of behavioral planning. Novel findings of neuronal activity have specified how neurons in this area take part in selective attention for action and in selecting an intended action. Furthermore, the involvement of the Lateral Prefrontal Cortex in the implementation of behavioral rules and in setting multiple behavioral goals has been discovered. Recent studies have begun to reveal neuronal mechanisms for strategic behavioral planning and for the development of knowledge that enables the planning of macrostructures of event-action sequences at the conceptual level.
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Concept-based behavioral planning and the Lateral Prefrontal Cortex.
Trends in cognitive sciences, 2007Co-Authors: Jun Tanji, Keisetsu Shima, Hajime MushiakeAbstract:Many lines of evidence implicate the Lateral Prefrontal Cortex (LPFC) in the executive control of behavior. In early studies, neuronal activity in this area was thought to retain information about forthcoming movements for a short period until they were executed. However, later studies have stressed its role in the cognitive aspects of behavioral planning, such as behavioral significance, behavioral rules and behavioral goals. The consequence of the intended action (i.e. a change in the state of the target object), rather than the intended movement, is primarily represented in the LPFC during planning. Recent studies show that the LPFC is involved in more abstract aspects of conceptual processes, such as in representing categories of multiple actions at the stage of behavioral planning.
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Activity in the Lateral Prefrontal Cortex Reflects Multiple Steps of Future Events in Action Plans
Neuron, 2006Co-Authors: Hajime Mushiake, Naohiro Saito, Kazuhiro Sakamoto, Yasuto Itoyama, Jun TanjiAbstract:To achieve a behavioral goal in a complex environment, we must plan multiple steps of motor behavior. On planning a series of actions, we anticipate future events that will occur as a result of each action and mentally organize the temporal sequence of events. To investigate the involvement of the Lateral Prefrontal Cortex (PFC) in such multistep planning, we examined neuronal activity in the PFC of monkeys performing a maze task that required the planning of stepwise cursor movements to reach a goal. During the preparatory period, PFC neurons reflected each of all forthcoming cursor movements, rather than arm movements. In contrast, in the primary motor Cortex, most neuronal activity reflected arm movements but little of cursor movements during the preparatory period, as well as during movement execution. Our data suggest that the PFC is involved primarily in planning multiple future events that occur as a consequence of behavioral actions.
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Integration of temporal order and object information in the monkey Lateral Prefrontal Cortex.
Journal of neurophysiology, 2003Co-Authors: Yoshihisa Ninokura, Hajime Mushiake, Jun TanjiAbstract:Generation of information about the temporal order of events is essential for the control of memory-based behavioral tasks. We studied cellular activity in the Lateral Prefrontal Cortex (LPFC) in two monkeys that were required to remember the temporal order in which visual objects were presented. In this report, we focus on cellular activity in response to the sequential appearance of three different objects. We identified cells that responded selectively to physical properties (color and shape) of objects (23%) in the ventral part of the LPFC and cells for which activity was selective for the numerical position (rank order) of objects (44%) in the dorsal part of the LPFC. We also identified cells for which activity was selective for both the physical properties and rank order of objects (30%). The third type of cells, distributed in the ventral LPFC, seems of importance in integrating the two categories of information, i.e., physical and temporal information about the occurrences of objects to construct sequential order information. Furthermore, we identified a distinct group of cells that exhibited selectivity for the sequence of presentation of the three objects. Our findings suggest that LPFC cells are involved in encoding temporal sequences of events when such information is required for planning forthcoming motor behavior.
René Marois - One of the best experts on this subject based on the ideXlab platform.
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A central role for the Lateral Prefrontal Cortex in goal-directed and stimulus-driven attention
Nature Neuroscience, 2010Co-Authors: Christopher L Asplund, J Jay Todd, Andy P Snyder, René MaroisAbstract:Attention can be driven by both stimulus- and goal-based processes. In the procedure used in this study, such 'bottom-up' and 'top-down' driven attentional processes appear to converge in the Lateral Prefrontal Cortex. Attention is the process that selects which sensory information is preferentially processed and ultimately reaches our awareness. Attention, however, is not a unitary process; it can be captured by unexpected or salient events (stimulus driven) or it can be deployed under voluntary control (goal directed), and these two forms of attention are implemented by largely distinct ventral and dorsal parieto-frontal networks. For coherent behavior and awareness to emerge, stimulus-driven and goal-directed behavior must ultimately interact. We found that the ventral, but not dorsal, network can account for stimulus-driven attentional limits to conscious perception, and that stimulus-driven and goal-directed attention converge in the Lateral Prefrontal component of that network. Although these results do not rule out dorsal network involvement in awareness when goal-directed task demands are present, they point to a general role for the Lateral Prefrontal Cortex in the control of attention and awareness.
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A central role for the Lateral Prefrontal Cortex in goal-directed and stimulus-driven attention
Nature neuroscience, 2010Co-Authors: Christopher L Asplund, J Jay Todd, Andy P Snyder, René MaroisAbstract:Attention is the process that selects which sensory information is preferentially processed and ultimately reaches our awareness. Attention, however, is not a unitary process; it can be captured by unexpected or salient events (stimulus driven) or it can be deployed under voluntary control (goal directed), and these two forms of attention are implemented by largely distinct ventral and dorsal parieto-frontal networks. For coherent behavior and awareness to emerge, stimulus-driven and goal-directed behavior must ultimately interact. We found that the ventral, but not dorsal, network can account for stimulus-driven attentional limits to conscious perception, and that stimulus-driven and goal-directed attention converge in the Lateral Prefrontal component of that network. Although these results do not rule out dorsal network involvement in awareness when goal-directed task demands are present, they point to a general role for the Lateral Prefrontal Cortex in the control of attention and awareness.
Christopher L Asplund - One of the best experts on this subject based on the ideXlab platform.
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A central role for the Lateral Prefrontal Cortex in goal-directed and stimulus-driven attention
Nature Neuroscience, 2010Co-Authors: Christopher L Asplund, J Jay Todd, Andy P Snyder, René MaroisAbstract:Attention can be driven by both stimulus- and goal-based processes. In the procedure used in this study, such 'bottom-up' and 'top-down' driven attentional processes appear to converge in the Lateral Prefrontal Cortex. Attention is the process that selects which sensory information is preferentially processed and ultimately reaches our awareness. Attention, however, is not a unitary process; it can be captured by unexpected or salient events (stimulus driven) or it can be deployed under voluntary control (goal directed), and these two forms of attention are implemented by largely distinct ventral and dorsal parieto-frontal networks. For coherent behavior and awareness to emerge, stimulus-driven and goal-directed behavior must ultimately interact. We found that the ventral, but not dorsal, network can account for stimulus-driven attentional limits to conscious perception, and that stimulus-driven and goal-directed attention converge in the Lateral Prefrontal component of that network. Although these results do not rule out dorsal network involvement in awareness when goal-directed task demands are present, they point to a general role for the Lateral Prefrontal Cortex in the control of attention and awareness.
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A central role for the Lateral Prefrontal Cortex in goal-directed and stimulus-driven attention
Nature neuroscience, 2010Co-Authors: Christopher L Asplund, J Jay Todd, Andy P Snyder, René MaroisAbstract:Attention is the process that selects which sensory information is preferentially processed and ultimately reaches our awareness. Attention, however, is not a unitary process; it can be captured by unexpected or salient events (stimulus driven) or it can be deployed under voluntary control (goal directed), and these two forms of attention are implemented by largely distinct ventral and dorsal parieto-frontal networks. For coherent behavior and awareness to emerge, stimulus-driven and goal-directed behavior must ultimately interact. We found that the ventral, but not dorsal, network can account for stimulus-driven attentional limits to conscious perception, and that stimulus-driven and goal-directed attention converge in the Lateral Prefrontal component of that network. Although these results do not rule out dorsal network involvement in awareness when goal-directed task demands are present, they point to a general role for the Lateral Prefrontal Cortex in the control of attention and awareness.
