scholarly journals A Neural Representation of Sequential States Within an Instructed Task

2010 ◽  
Vol 104 (5) ◽  
pp. 2831-2849 ◽  
Author(s):  
Michael Campos ◽  
Boris Breznen ◽  
Richard A. Andersen
Keyword(s):  
Internal Representation ◽  
Neural Representation ◽  
Neural Basis ◽  
Lateral Intraparietal Area ◽  
State Dependent ◽  
Sensorimotor Transformations ◽  
Saccade Task ◽  
Anticipatory Activity ◽  
Supplementary Eye Fields ◽  
The Brain

In the study of the neural basis of sensorimotor transformations, it has become clear that the brain does not always wait to sense external events and afterward select the appropriate responses. If there are predictable regularities in the environment, the brain begins to anticipate the timing of instructional cues and the signals to execute a response, revealing an internal representation of the sequential behavioral states of the task being performed. To investigate neural mechanisms that could represent the sequential states of a task, we recorded neural activity from two oculomotor structures implicated in behavioral timing—the supplementary eye fields (SEF) and the lateral intraparietal area (LIP)—while rhesus monkeys performed a memory-guided saccade task. The neurons of the SEF were found to collectively encode the progression of the task with individual neurons predicting and/or detecting states or transitions between states. LIP neurons, while also encoding information about the current temporal interval, were limited with respect to SEF neurons in two ways. First, LIP neurons tended to be active when the monkey was planning a saccade but not in the precue or intertrial intervals, whereas SEF neurons tended to have activity modulation in all intervals. Second, the LIP neurons were more likely to be spatially tuned than SEF neurons. SEF neurons also show anticipatory activity. The state-selective and anticipatory responses of SEF neurons support two complementary models of behavioral timing, state dependent and accumulator models, and suggest that each model describes a contribution SEF makes to timing at different temporal resolutions.

scholarly journals Influence of cognitive control on semantic representation

2016 ◽  
Author(s):  
Waitsang Keung ◽  
Daniel Osherson ◽  
Jonathan D. Cohen
Keyword(s):  
Cognitive Control ◽  
Semantic Representation ◽  
Semantic Knowledge ◽  
Neural Representation ◽  
Neural Basis ◽  
Attentional Modulation ◽  
Task Instructions ◽  
Similarity Relationships ◽  
Context Specific ◽  
The Brain

AbstractThe neural representation of an object can change depending on its context. For instance, a horse may be more similar to a bear than to a dog in terms of size, but more similar to a dog in terms of domesticity. We used behavioral measures of similarity together with representational similarity analysis and functional connectivity of fMRI data in humans to reveal how the neural representation of semantic knowledge can change to match the current goal demand. Here we present evidence that objects similar to each other in a given context are also represented more similarly in the brain and that these similarity relationships are modulated by context specific activations in frontal areas.Significance statementThe judgment of similarity between two objects can differ in different contexts. Here we report a study that tested the hypothesis that brain areas associated with task context and cognitive control modulate semantic representations of objects in a task-specific way.We first demonstrate that task instructions impact how objects are represented in the brain. We then show that the expression of these representations is correlated with activity in regions of frontal cortex widely thought to represent context, attention and control.In addition, we introduce spatial variance as a novel index of representational expression and attentional modulation. This promises to lay the groundwork for more exacting studies of the neural basis of semantics, as well as the dynamics of attentional modulation.

scholarly journals Separate Representations of Target and Timing Cue Locations in the Supplementary Eye Fields

2009 ◽  
Vol 101 (1) ◽  
pp. 448-459 ◽  
Author(s):  
Michael Campos ◽  
Boris Breznen ◽  
Richard A. Andersen
Keyword(s):  
Eye Movement ◽  
Brain Area ◽  
Target Position ◽  
Oculomotor System ◽  
Small Population ◽  
Oculomotor Control ◽  
Brain Areas ◽  
Saccade Task ◽  
Supplementary Eye Fields ◽  
The Brain

When different stimuli indicate where and when to make an eye movement, the brain areas involved in oculomotor control must selectively plan an eye movement to the stimulus that encodes the target position and also encode the information available from the timing cue. This could pose a challenge to the oculomotor system since the representation of the timing stimulus location in one brain area might be interpreted by downstream neurons as a competing motor plan. Evidence from diverse sources has suggested that the supplementary eye fields (SEF) play an important role in behavioral timing, so we recorded single-unit activity from SEF to characterize how target and timing cues are encoded in this region. Two monkeys performed a variant of the memory-guided saccade task, in which a timing stimulus was presented at a randomly chosen eccentric location. Many spatially tuned SEF neurons encoded only the location of the target and not the timing stimulus, whereas several other SEF neurons encoded the location of the timing stimulus and not the target. The SEF population therefore encoded the location of each stimulus with largely distinct neuronal subpopulations. For comparison, we recorded a small population of lateral intraparietal (LIP) neurons in the same task. We found that most LIP neurons that encoded the location of the target also encoded the location of the timing stimulus after its presentation, but selectively encoded the intended eye movement plan in advance of saccade initiation. These results suggest that SEF, by conditionally encoding the location of instructional stimuli depending on their meaning, can help identify which movement plan represented in other oculomotor structures, such as LIP, should be selected for the next eye movement.

scholarly journals Representation of Borders and Swimming Kinematics in the Brain of Freely-Navigating Fish

2018 ◽  
Author(s):  
Ehud Vinepinsky ◽  
Lear Cohen ◽  
Shay Perchik ◽  
Ohad Ben-Shahar ◽  
Opher Donchin ◽  
...  
Keyword(s):  
Brain Region ◽  
Building Blocks ◽  
Neural Representation ◽  
Water Tank ◽  
Border Cells ◽  
Head Direction ◽  
Neural Basis ◽  
Head Direction Cells ◽  
Swimming Kinematics ◽  
The Brain

AbstractLike most animals, the survival of fish depends crucially on navigation in space. This capacity has been documented in numerous behavioral studies that have revealed navigation strategies and the sensory modalities used for navigation. However, virtually nothing is known about how freely swimming fish represent space and locomotion in the brain to enable successful navigation. Using a novel wireless neural recording system, we measured the activity of single neurons in the goldfish lateral pallium, a brain region known to be involved in spatial memory and navigation, while the fish swam freely in a two-dimensional water tank. Four cell types were identified: border cells, head direction cells, speed cells and conjunction head direction with speed. Border cells were active when the fish was near the boundary of the environment. Head direction cells were shown to encode head direction. Speed cells only encoded the absolute speed independent of direction suggestive of an odometry signal. Finally, the conjunction of head direction with speed cells represented the velocity of the fish. This study thus sheds light on how information related to navigation is represented in the brain of swimming fish, and addresses the fundamental question of the neural basis of navigation in this diverse group of vertebrates. The similarities between our observations in fish and earlier findings in mammals may indicate that the networks controlling navigation in vertebrate originate from an ancient circuit common across vertebrates.SummaryNavigation is a fundamental behavioral capacity facilitating survival in many animal species. Fish is one lineage where navigation has been explored behaviorally, but it remains unclear how freely swimming fish represent space and locomotion in the brain. This is a key open question in our understanding of navigation in fish and more generally in understanding the evolutionary origin of the brain’s navigation system. To address this issue, we recorded neuronal signals from the brain of freely swimming goldfish and successfully identified representations of border and swimming kinematics in a brain region known to be associated with navigation. Our findings thus provide a glimpse into the building blocks of the neural representation underlying fish navigation. The similarity of the representation in fish with that of mammals may be key evidence supporting a preserved ancient mechanism across brain evolution.

Introduction

2001 ◽  
Vol 4 (2) ◽  
pp. 101-103
Author(s):  
David W. Green
Keyword(s):  
Language Processing ◽  
Neural Activity ◽  
Neural Representation ◽  
Special Issue ◽  
Neural Basis ◽  
And Control ◽  
The Brain ◽  
Electrophysiological Methods ◽  
Neuroimaging Techniques ◽  
Do So

The papers in this Special Issue focus on the use of neuroimaging techniques to answer questions about the neural representation, processing and control of two languages. Neuropsychological data from bilingual aphasics remain vital if we are to establish the neural basis of language (see Paradis, 1995) but lesion-deficit studies alone cannot tell us how neural activity relates to ongoing language processing. Modern neuroimaging methods provide a means to do so. There are two broad classes of such methods: electrophysiological methods allow us to answer questions about when a particular process occurs whereas haemodynamic methods allow us to answer the complementary question of where in the brain such a process is carried out. Before giving a thumb-nail sketch of the papers in this Special Issue, I briefly discuss each class of method.

scholarly journals State dependence of adaptation of force output following movement observation

2013 ◽  
Vol 110 (5) ◽  
pp. 1246-1256 ◽  
Author(s):  
Paul A. Wanda ◽  
Gang Li ◽  
Kurt A. Thoroughman
Keyword(s):  
Action Observation ◽  
Motor Task ◽  
State Dependence ◽  
Lateral Force ◽  
Neural Representation ◽  
The Novel ◽  
Learning Effects ◽  
Force Output ◽  
State Dependent ◽  
The Brain

Humans readily learn to move through direct physical practice and by watching the movements of others. Some researchers have proposed that action observation can inform subsequent changes in control through the acquisition of a neural representation of the novel dynamics, but to date learning following observation has been described by kinematic metrics. Here we designed an experiment to consider the specificity of adaptation to novel dynamic perturbations at the level of force generation. We measured changes in temporal patterns of force output following either the performance or observation of movements perturbed by either position- or velocity-dependent dynamic environments to 1) establish whether previously described observational motor learning effects were attributable to changes in predictive limb control and 2) determine whether such adaptation reflected a learned dependence on limb states appropriate to the haptic environment. We found that subjects who observed perturbed movements produced significant compensatory changes in their lateral force output, despite never directly experiencing force perturbations firsthand while performing the motor task. The time series of observers' adapted force outputs suggested that the state dependence of observed dynamics shapes adaptation. We conclude that the brain can transform observation of kinematics into state-dependent adaptation of reach dynamics.

scholarly journals Spatial constancy and the brain: insights from neural networks

2007 ◽  
Vol 362 (1479) ◽  
pp. 375-382 ◽  
Author(s):  
Robert L White ◽  
Lawrence H Snyder
Keyword(s):  
Neural Networks ◽  
Spatial Information ◽  
Internal Representation ◽  
Visual Space ◽  
Spatial Location ◽  
Striking Similarity ◽  
Spatial Updating ◽  
Gaze Shift ◽  
Lateral Intraparietal Area ◽  
The Brain

To form an accurate internal representation of visual space, the brain must accurately account for movements of the eyes, head or body. Updating of internal representations in response to these movements is especially important when remembering spatial information, such as the location of an object, since the brain must rely on non-visual extra-retinal signals to compensate for self-generated movements. We investigated the computations underlying spatial updating by constructing a recurrent neural network model to store and update a spatial location based on a gaze shift signal, and to do so flexibly based on a contextual cue. We observed a striking similarity between the patterns of behaviour produced by the model and monkeys trained to perform the same task, as well as between the hidden units of the model and neurons in the lateral intraparietal area (LIP). In this report, we describe the similarities between the model and single unit physiology to illustrate the usefulness of neural networks as a tool for understanding specific computations performed by the brain.

scholarly journals Food Entrainment, Arousal, and Motivation in the Neonatal Rabbit Pup

2021 ◽  
Vol 15 ◽  
Author(s):  
Mario Caba ◽  
Michael N. Lehman ◽  
Mario Daniel Caba-Flores
Keyword(s):  
Rabbit Model ◽  
Hypothalamic Nucleus ◽  
Neural Basis ◽  
Fluid Ingestion ◽  
Conditioned Learning ◽  
Neural Substrate ◽  
Corticolimbic System ◽  
Anticipatory Activity ◽  
The Brain

In the newborn rabbit, the light entrainable circadian system is immature and once a day nursing provides the primary timing cue for entrainment. In advance of the mother’s arrival, pups display food anticipatory activity (FAA), and metabolic and physiological parameters are synchronized to this daily event. Central structures in the brain are also entrained as indicated by expression of Fos and Per1 proteins, GFAP, a glial marker, and cytochrome oxidase activity. Under fasting conditions, several of these rhythmic parameters persist in the periphery and brain, including rhythms in the olfactory bulb (OB). Here we provide an overview of these physiological and neurobiological changes and focus on three issues, just beginning to be examined in the rabbit. First, we review evidence supporting roles for the organum vasculosum of lamina terminalis (OVLT) and median preoptic nucleus (MnPO) in homeostasis of fluid ingestion and the neural basis of arousal, the latter which also includes the role of the orexigenic system. Second, since FAA in association with the daily visit of the mother is an example of conditioned learning, we review evidence for changes in the corticolimbic system and identified nuclei in the amygdala and extended amygdala as part of the neural substrate responsible for FAA. Third, we review recent evidence supporting the role of oxytocinergic cells of the paraventricular hypothalamic nucleus (PVN) as a link to the autonomic system that underlies physiological events, which occur in preparation for the upcoming next daily meal. We conclude that the rabbit model has contributed to an overall understanding of food entrainment.

scholarly journals Activation State-Dependent Substrate Gating in Ca2+/Calmodulin-Dependent Protein Kinase II

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
D. E. Johnson ◽  
A. Hudmon
Keyword(s):  
Protein Kinase ◽  
Catalytic Domain ◽  
Intrinsic Property ◽  
Dependent Protein Kinase ◽  
Calcium Calmodulin Dependent ◽  
State Dependent ◽  
Protein Kinase Ii ◽  
Dependent Protein ◽  
Substrate Phosphorylation ◽  
The Brain

Calcium/calmodulin-dependent protein kinase II (CaMKII) is highly concentrated in the brain where its activation by the Ca2+sensor CaM, multivalent structure, and complex autoregulatory features make it an ideal translator of Ca2+signals created by different patterns of neuronal activity. We provide direct evidence that graded levels of kinase activity and extent of T287(T286αisoform) autophosphorylation drive changes in catalytic output and substrate selectivity. The catalytic domains of CaMKII phosphorylate purified PSDs much more effectively when tethered together in the holoenzyme versus individual subunits. Using multisubstrate SPOT arrays, high-affinity substrates are preferentially phosphorylated with limited subunit activity per holoenzyme, whereas multiple subunits or maximal subunit activation is required for intermediate- and low-affinity, weak substrates, respectively. Using a monomeric form of CaMKII to control T287autophosphorylation, we demonstrate that increased Ca2+/CaM-dependent activity for all substrates tested, with the extent of weak, low-affinity substrate phosphorylation governed by the extent of T287autophosphorylation. Our data suggest T287autophosphorylation regulates substrate gating, an intrinsic property of the catalytic domain, which is amplified within the multivalent architecture of the CaMKII holoenzyme.

scholarly journals Subjective value and decision entropy are jointly encoded by aligned gradients across the human brain

2020 ◽  
Author(s):  
Sebastian Bobadilla-Suarez ◽  
Olivia Guest ◽  
Bradley C. Love
Keyword(s):  
Prefrontal Cortex ◽  
Human Brain ◽  
Ventromedial Prefrontal Cortex ◽  
Neural Representation ◽  
Retrospective Evaluation ◽  
Systematic Fashion ◽  
Subjective Value ◽  
Fmri Analysis ◽  
The Relationship ◽  
The Brain

AbstractRecent work has considered the relationship between value and confidence in both behavior and neural representation. Here we evaluated whether the brain organizes value and confidence signals in a systematic fashion that reflects the overall desirability of options. If so, regions that respond to either increases or decreases in both value and confidence should be widespread. We strongly confirmed these predictions through a model-based fMRI analysis of a mixed gambles task that assessed subjective value (SV) and inverse decision entropy (iDE), which is related to confidence. Purported value areas more strongly signalled iDE than SV, underscoring how intertwined value and confidence are. A gradient tied to the desirability of actions transitioned from positive SV and iDE in ventromedial prefrontal cortex to negative SV and iDE in dorsal medial prefrontal cortex. This alignment of SV and iDE signals could support retrospective evaluation to guide learning and subsequent decisions.

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