scholarly journals Reliable population utility signal from diverse economic value coding in orbitofrontal neurons

2021 ◽  
Author(s):  
Simone Ferrari-Toniolo ◽  
Wolfram Schultz
Keyword(s):  
Reward Magnitude ◽  
Economic Value ◽  
Population Level ◽  
Axiomatic Approach ◽  
Neuronal Population ◽  
Risk Attitudes ◽  
Probability Weighting ◽  
Value Functions ◽  
Single Neurons ◽  
Subjective Value

Economic value encapsulates the subjective combination of reward magnitude and probability. We investigated the mechanism for subjective value computation in single neurons using an economic axiomatic approach. We found that single neurons in the macaque orbitofrontal cortex, known to be sensitive to reward magnitude and probability, encode the economic value functions (utility and probability weighting) in a heterogeneous manner, such that the activity of individual neurons did not match the animal's choices. However, the utility and probability weighting code from a population of these varied neurons reliably matched the animals' choices and risk attitudes. Thus, the neuronal population code for economic value amounted to a distributional representation of the formal economic functions. With a diverse single-unit economic value code converging into a reliable population-level utility code, this scheme suggests a brain mechanism for the flexible accommodation of multiple choice patterns and risk attitudes.

scholarly journals Proteolytic Remodeling of Perineuronal Nets: Effects on Synaptic Plasticity and Neuronal Population Dynamics

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
P. Lorenzo Bozzelli ◽  
Seham Alaiyed ◽  
Eunyoung Kim ◽  
Sonia Villapol ◽  
Katherine Conant
Keyword(s):  
Population Dynamics ◽  
Synaptic Plasticity ◽  
Synaptic Input ◽  
Neuronal Plasticity ◽  
Population Level ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Neuronal Population ◽  
Perineuronal Nets ◽  
Perineuronal Net

The perineuronal net (PNN) represents a lattice-like structure that is prominently expressed along the soma and proximal dendrites of parvalbumin- (PV-) positive interneurons in varied brain regions including the cortex and hippocampus. It is thus apposed to sites at which PV neurons receive synaptic input. Emerging evidence suggests that changes in PNN integrity may affect glutamatergic input to PV interneurons, a population that is critical for the expression of synchronous neuronal population discharges that occur with gamma oscillations and sharp-wave ripples. The present review is focused on the composition of PNNs, posttranslation modulation of PNN components by sulfation and proteolysis, PNN alterations in disease, and potential effects of PNN remodeling on neuronal plasticity at the single-cell and population level.

scholarly journals Pace of movement: the role of single neurons in the subthalamic nucleus

2019 ◽  
Vol 130 (6) ◽  
pp. 1835-1840 ◽  
Author(s):  
Ariel Tankus ◽  
Anat Mirelman ◽  
Nir Giladi ◽  
Itzhak Fried ◽  
Jeffrey M. Hausdorff
Keyword(s):  
Motor Control ◽  
Subthalamic Nucleus ◽  
Critical Factor ◽  
Neuronal Population ◽  
Distributed Model ◽  
Single Neurons ◽  
Direct Recording ◽  
Neurosurgical Patients ◽  
Upper And Lower Extremities ◽  
Neuronal Recruitment

OBJECTIVEThe ability to modulate the pace of movement is a critical factor in the smooth operation of the motor system. The authors recently described distinct and overlapping representations of movement kinematics in the subthalamic nucleus (STN), but it is still unclear how movement pace is modulated according to the demands of the task at the neuronal level in this area. The goal of this study was to clarify how different movement paces are being controlled by neurons in the STN.METHODSThe authors performed direct recording of the electrical activity of single neurons in the STN of neurosurgical patients with Parkinson’s disease undergoing implantation of a deep brain stimulator under local anesthesia while the patients performed repetitive foot and hand movements intraoperatively at multiple paces.RESULTSA change was observed in the neuronal population controlling the movement for each pace. The mechanism for switching between these controlling populations differs for hand and foot movements.CONCLUSIONSThese findings suggest that disparate schemes are utilized in the STN for neuronal recruitment for motor control of the upper and lower extremities. The results indicate a distributed model of motor control within the STN, where the active neuronal population changes when modifying the task condition and pace.

scholarly journals Structure in Neural Activity during Observed and Executed Movements Is Shared at the Neural Population Level, Not in Single Neurons

Cell Reports ◽  
2020 ◽  
Vol 32 (6) ◽  
pp. 108006 ◽  
Author(s):  
Xiyuan Jiang ◽  
Hemant Saggar ◽  
Stephen I. Ryu ◽  
Krishna V. Shenoy ◽  
Jonathan C. Kao
Keyword(s):  
Neural Activity ◽  
Population Level ◽  
Neural Population ◽  
Single Neurons

scholarly journals Saccade vigor partly reflects the subjective economic value of the visual stimulus

2019 ◽  
Author(s):  
Tehrim Yoon ◽  
Afareen Jaleel ◽  
Alaa A. Ahmed ◽  
Reza Shadmehr
Keyword(s):  
Reaction Time ◽  
Peak Velocity ◽  
Economic Value ◽  
Single Stimulus ◽  
Peripheral Location ◽  
Subjective Value ◽  
Abstract Stimuli ◽  
The Brain ◽  
Mathematical Construct ◽  
Subject Differences

AbstractDecisions are made based on the subjective value that the brain assigns to options. However, subjective value is a mathematical construct that cannot be measured directly, but rather inferred from choices. Recent results have demonstrated that reaction time and velocity of movements are modulated by reward, raising the possibility that there is a link between how the brain evaluates an option, and how it controls movements toward that option. Here, we asked people to choose among risky options represented by abstract stimuli, some associated with gain, others with loss. From their choices in decision trials we estimated the subjective value that they assigned to each stimulus. In probe trials, they were presented with a single stimulus at center and made a saccade to a peripheral location. We found that the reaction time and peak velocity of that saccade varied roughly linearly from loss to gain with the subjective value of the stimulus. Naturally, participants differed in how much they valued a given stimulus. Remarkably, those who valued a stimulus more, as evidenced by their choices in decision trials, tended to move with greater vigor in response to that stimulus in probe trials. Thus, saccade vigor partly reflected the subjective value that the brain assigned the stimulus. However, the influence of subjective value on vigor was only a modest predictor of preference: vigor in probe trials allowed us to predict choice in decision trials with roughly 60% accuracy.New and NoteworthyWe found that saccade vigor tends to vary monotonically with subjective value: smallest for stimuli that predict a loss, and highest for stimuli that predict a gain. Notably, between-subject differences in valuation could be gleaned from the between-subject differences in their patterns of vigor. However, the influence of subjective value on vigor was modest, allowing partial ability to infer subjective value for the purpose of predicting choice in decision trials.

scholarly journals Reward-specific satiety affects subjective value signals in orbitofrontal cortex during multicomponent economic choice

2021 ◽  
Vol 118 (30) ◽  
pp. e2022650118
Author(s):  
Alexandre Pastor-Bernier ◽  
Arkadiusz Stasiak ◽  
Wolfram Schultz
Keyword(s):  
Orbitofrontal Cortex ◽  
Economic Value ◽  
Revealed Preference ◽  
Value Change ◽  
Neuronal Coding ◽  
Preference Theory ◽  
Subjective Value ◽  
Reward Value ◽  
Value Loss ◽  
Reward Functions

Sensitivity to satiety constitutes a basic requirement for neuronal coding of subjective reward value. Satiety from natural ongoing consumption affects reward functions in learning and approach behavior. More specifically, satiety reduces the subjective economic value of individual rewards during choice between options that typically contain multiple reward components. The unconfounded assessment of economic reward value requires tests at choice indifference between two options, which is difficult to achieve with sated rewards. By conceptualizing choices between options with multiple reward components (“bundles”), Revealed Preference Theory may offer a solution. Despite satiety, choices against an unaltered reference bundle may remain indifferent when the reduced value of a sated bundle reward is compensated by larger amounts of an unsated reward of the same bundle, and then the value loss of the sated reward is indicated by the amount of the added unsated reward. Here, we show psychophysically titrated choice indifference in monkeys between bundles of differently sated rewards. Neuronal chosen value signals in the orbitofrontal cortex (OFC) followed closely the subjective value change within recording periods of individual neurons. A neuronal classifier distinguishing the bundles and predicting choice substantiated the subjective value change. The choice between conventional single rewards confirmed the neuronal changes seen with two-reward bundles. Thus, reward-specific satiety reduces subjective reward value signals in OFC. With satiety being an important factor of subjective reward value, these results extend the notion of subjective economic reward value coding in OFC neurons.

Response of Anterior Parietal Cortex to Cutaneous Flutter Versus Vibration

1999 ◽  
Vol 82 (1) ◽  
pp. 16-33 ◽  
Author(s):  
M. Tommerdahl ◽  
K. A. Delemos ◽  
B. L. Whitsel ◽  
O. V. Favorov ◽  
C. B. Metz
Keyword(s):  
Firing Rate ◽  
Population Level ◽  
Early Response ◽  
Neuronal Population ◽  
Stimulus Onset ◽  
Skin Site ◽  
Intrinsic Signal ◽  
Optical Intrinsic Signal ◽  
Area 3B ◽  
Stimulation Of

The response of anesthetized squirrel monkey anterior parietal (SI) cortex to 25 or 200 Hz sinusoidal vertical skin displacement stimulation was studied using the method of optical intrinsic signal (OIS) imaging. Twenty-five-Hertz (“flutter”) stimulation of a discrete skin site on either the hindlimb or forelimb for 3–30 s evoked a prominent increase in absorbance within cytoarchitectonic areas 3b and 1 in the contralateral hemisphere. This response was confined to those area 3b/1 regions occupied by neurons with a receptive field (RF) that includes the stimulated skin site. In contrast, same-site 200-Hz stimulation (“vibration”) for 3–30 s evoked a decrease in absorbance in a much larger territory (most frequently involving areas 3b, 1, and area 3a, but in some subjects area 2 as well) than the region that undergoes an increase in absorbance during 25-Hz flutter stimulation. The increase in absorbance evoked by 25-Hz flutter developed quickly and remained relatively constant for as long as stimulation continued (stimulus duration never exceeded 30 s). At 1–3 s after stimulus onset, the response to 200-Hz stimulation, like the response to 25-Hz flutter, consisted of a localized increase in absorbance limited to the topographically appropriate region of area 3b and/or area 1. With continuing 200-Hz stimulation, however, the early response declined, and by 4–6 s after stimulus onset, it was replaced by a prominent and spatially extensive decrease in absorbance. The spike train responses of single quickly adapting (QA) neurons were recorded extracellularly during microelectrode penetrations that traverse the optically responding regions of areas 3b and 1. Onset of either 25- or 200-Hz stimulation at a site within the cutaneous RF of a QA neuron was accompanied by a substantial increase in mean spike firing rate. With continued 200-Hz stimulation, however, QA neuron mean firing rate declined rapidly (typically within 0.5–1.0 s) to a level below that recorded at the same time after onset of same-site 25-Hz stimulation. For some neurons, the mean firing rate after the initial 0.5–1 s of an exposure to 200-Hz stimulation of the RF decreased to a level below the level of background (“spontaneous”) activity. The decline in both the stimulus-evoked increases in absorbance in areas 3b/1 and spike discharge activity of area 3b/1 neurons within only a few seconds of the onset of 200-Hz skin stimulation raised the possibility that the predominant effect of continuous 200-Hz stimulation for >3 s is inhibition of area 3b/1 QA neurons. This possibility was evaluated at the neuronal population level by comparing the intrinsic signal evoked in areas 3b/1 by 25-Hz skin stimulation to the intrinsic signal evoked by a same-site skin stimulus containing both 25- and 200-Hz sinusoidal components (a “complex waveform stimulus”). Such experiments revealed that the increase in absorbance evoked in areas 3b/1 by a stimulus having both 25- and 200-Hz components was substantially smaller (especially at times >3 s after stimulus onset) than the increase in absorbance evoked by “pure” 25-Hz stimulation of the same skin site. It is concluded that within a brief time (within 1–3 s) after stimulus onset, 200-Hz skin stimulation elicits a powerful inhibitory action on area 3b/1 QA neurons. The findings appear generally consistent with the suggestion that the activity of neurons in cortical regions other than areas 3b and 1 play the leading role in the processing of high-frequency (≥200 Hz) vibrotactile stimuli.

scholarly journals The African buffalo: A villain for inter-species spread of infectious diseases in southern Africa

2012 ◽  
Vol 79 (2) ◽  
Author(s):  
Anita L. Michel ◽  
Roy G. Bengis
Keyword(s):  
Economic Value ◽  
Clinical Signs ◽  
Population Level ◽  
Tourism Industry ◽  
Sub Saharan Africa ◽  
Diagnostic Tools ◽  
African Buffalo ◽  
Ecological Value ◽  
Valley Fever ◽  
Conservation Projects

The African buffalo (Syncerus caffer) is a large wild bovid which until recently ranged across all but the driest parts of sub-Saharan Africa, and their local range being limited to about 20 km from surface water. They are of high ecological value due to their important role as bulk feeders in the grazing hierarchy. They also have high economic value, because they are one of the sought after ‘Big Five’ in the eco-tourism industry. In Africa, buffaloes have been recognised for some time as an important role player in the maintenance and transmission of a variety of economically important livestock diseases at the wildlife and/or livestock interface. These include African strains of foot-and-mouth disease (FMD), Corridor disease (theileriosis), bovine tuberculosis and bovine brucellosis. For a number of other diseases of veterinary importance, African buffaloes may also serve as amplifier or incidental host, whereby infection with the causative pathogens may cause severe clinical signs such as death or abortion as in the case of anthrax and Rift Valley fever, or remain mild or subclinical for example heartwater. The long term health implications of most of those infections on the buffalo at a population level is usually limited, and they do not pose a threat on the population’s survival. Because of their ability to harbour and transmit important diseases to livestock, their sustainable future in ecotourism, trade and transfrontier conservation projects become complex and costly and reliable diagnostic tools are required to monitor these infections in buffalo populations.

The case against economic values in the orbitofrontal cortex (or anywhere else in the brain)

2020 ◽  
Author(s):  
Benjamin Hayden ◽  
Yael Niv
Keyword(s):  
Orbitofrontal Cortex ◽  
Economic Value ◽  
Brain Regions ◽  
Process Models ◽  
Neural Basis ◽  
Economic Concept ◽  
Free Process ◽  
Subjective Value ◽  
Epistemic Constraints ◽  
The Brain

Much of traditional neuroeconomics proceeds from the hypothesis that value is reified in the brain, that is, that there are neurons or brain regions whose responses serve the discrete purpose of encoding value. This hypothesis is supported by the finding that the activity of many neurons covaries with subjective value as estimated in specific tasks and has led to the idea that the primary function of the orbitofrontal cortex is to compute and signal economic value. Here we consider an alternative: that economic value, in the cardinal, common-currency sense, is not represented in the brain and used for choice by default. This idea is motivated by consideration of the economic concept of value, which places important epistemic constraints on our ability to identify its neural basis. It is also motivated by the behavioral economics literature, especially work on heuristics, which proposes value-free process models for much if not all of choice. Finally, it is buoyed by recent neural and behavioral findings regarding how animals and humans learn to choose between options. In light of our hypothesis, we critically reevaluate putative neural evidence for the representation of value and explore an alternative: direct learning of action policies. We delineate how this alternative can provide a robust account of behavior that concords with existing empirical data.

Microsaccade direction reflects the economic value of potential saccade goals and predicts saccade choice

2016 ◽  
Vol 115 (2) ◽  
pp. 741-751 ◽  
Author(s):  
Gongchen Yu (余功臣) ◽  
Baijie Xu (徐佰杰) ◽  
Yuchen Zhao (赵宇晨) ◽  
Beizhen Zhang (张倍祯) ◽  
Mingpo Yang (杨明坡) ◽  
...  
Keyword(s):  
Small Amplitude ◽  
Human Subjects ◽  
Economic Value ◽  
Decision Processes ◽  
Complete Darkness ◽  
Sensory Stimuli ◽  
Attentional Processes ◽  
Cognitive States ◽  
Subjective Value ◽  
Voluntary Choice

Microsaccades are small-amplitude (typically <1°), ballistic eye movements that occur when attempting to fixate gaze. Initially thought to be generated randomly, it has recently been established that microsaccades are influenced by sensory stimuli, attentional processes, and certain cognitive states. Whether decision processes influence microsaccades, however, is unknown. Here, we adapted two classic economic tasks to examine whether microsaccades reflect evolving saccade decisions. Volitional saccade choices of monkey and human subjects provided a measure of the subjective value of targets. Importantly, analyses occurred during a period of complete darkness to minimize the known influence of sensory and attentional processes on microsaccades. As the time of saccadic choice approached, microsaccade direction became the following: 1) biased toward targets as a function of their subjective value and 2) predictive of upcoming, voluntary choice. Our results indicate that microsaccade direction is influenced by and is a reliable tell of evolving saccade decisions. Our results are consistent with dynamic decision processes within the midbrain superior colliculus; that is, microsaccade direction is influenced by the transition of activity toward caudal saccade regions associated with high saccade value and/or future saccade choice.

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