scholarly journals Neural Mechanisms of Bias and Sensitivity in Animal Models of Decision Making

1970 ◽  
Vol 6 (1) ◽  
pp. 1-9
Author(s):  
Hiroshi Nishida ◽  
Muneyoshi Takahashi ◽  
Gary D. Bird ◽  
Jan Lauwereyns
Keyword(s):  
Stimulus Onset ◽  
Future Research ◽  
General Increase ◽  
Neural Recordings ◽  
Slowing Down ◽  
Action Mechanisms ◽  
Speed Up ◽  
Types Of Information ◽  
Basic Features ◽  
The Brain

Animals perceive stimuli in their environment and are required to make motor responses according to this perception. The perception-to-action mechanisms rely on the accumulation of neural activity in specific areas of the brain that need to reach a threshold in order for the action to be initiated. These mechanisms can be influenced by various types of information and prospective outcomes; that is, contextual factors can speed up or slow down the processes. Here we describe how behavioral paradigms coupled with neural recordings can illustrate two basic features of the speeding up (or slowing down) of the perception-to-action mechanisms. The features are bias (a general increase in decision activity prior to stimulus onset) and sensitivity (a change in the cumulative firing rate up to a decision point). We thenpropose the direction for future research emphasizing the need to examine bias and sensitivity with a focus on dynamics.

scholarly journals Warning Signals Influence Motor Processing

2007 ◽  
Vol 97 (2) ◽  
pp. 1600-1609 ◽  
Author(s):  
Jillian H. Fecteau ◽  
Douglas P. Munoz
Keyword(s):  
Motor Neurons ◽  
Neural Activity ◽  
Warning Signal ◽  
Future Research ◽  
Target Task ◽  
Motor Processing ◽  
Fixation Marker ◽  
Speed Up ◽  
The Brain ◽  
Do So

When observers initiate responses to visual targets, they do so sooner when a preceding stimulus indicates that the target will appear shortly. This consequence of a warning signal may change neural activity in one of four ways. On the sensory side, the warning signal may speed up the rate at which the target is registered by the brain or enhance the magnitude of its signal. On the motor end, the warning signal may lower the threshold required to initiate a response or speed up the rate at which activity accumulates to reach threshold. Here, we describe which explanation is better supported. To accomplish this end, monkeys performed different versions of a cue-target task while we monitored the activity of visuomotor and motor neurons in the superior colliculus. Although the cue target task was designed to measure the properties of reflexive spatial attention, there are two events in this task that produce nonspecific warning effects: a central reorienting event (brightening of central fixation marker) that is used to direct attention away from the cue, and the presentation of the cue itself. Monopolizing on these tendencies, we show that warning effects are associated with several changes in neural activity: the target-related response is enhanced, the threshold for initiating a saccade is lowered, and the rate at which activity accumulates toward threshold rises faster. Ultimately, the accumulation of activity toward threshold predicted behavior most closely. In the discussion, we describe the implications and limitations of these data for theories of warning effects and potential avenues for future research.

The Recalibration Effect of Time Perception Using a Virtual Environment

2012 ◽  
Vol 21 (2) ◽  
pp. 203-212 ◽  
Author(s):  
Kyung-Ae Cha ◽  
Sung-Bin Hong ◽  
Sung-Ho Woo ◽  
Hyun Taek Kim
Keyword(s):  
Virtual Environment ◽  
Time Perception ◽  
Stimulus Onset ◽  
Depth Of Field ◽  
Future Research ◽  
Light Sources ◽  
Display Device ◽  
Light Emitting ◽  
Onset Asynchrony ◽  
The Brain

It has been demonstrated that recalibrations of audio-visual asynchrony are likely to occur in sensory processing rather than in the higher domains of cognition in the brain. The aim of the present study was to investigate recalibration of time perception to judge auditory and visual input simultaneity using a virtual environment (VE). A virtual corridor built for this experiment has depth of field, and includes six light sources (light-emitting diodes, LEDs) affixed on a computer monitor, which appear to be situated at different distances. Subjects in the VE were presented with both the flashes of LEDs and associated bursts of white noise with random stimulus onset asynchrony (SOA). Even though the auditory and visual stimuli were presented from the same distance on the display device, the subjects showed different time recalibration effects (TREs) depending on subjects' tendencies of immersion in VE. The results suggest that the differences in the TREs can be explained by subject-specific tendencies such as absorption to stimuli, which can construct subjective reality in top-down processing. Future research on neural substrates of recalibration for simultaneity will contribute toward understanding of how the brain creates the representation of spatiotemporal coherence.

scholarly journals Involvement of Microglia in the Pathophysiology of Intracranial Aneurysms and Vascular Malformations—A Short Overview

2021 ◽  
Vol 22 (11) ◽  
pp. 6141
Author(s):  
Teodora Larisa Timis ◽  
Ioan Alexandru Florian ◽  
Sergiu Susman ◽  
Ioan Stefan Florian
Keyword(s):  
Immune Cells ◽  
Arteriovenous Malformations ◽  
Intracranial Aneurysms ◽  
Immune Cell ◽  
Vascular Malformations ◽  
Cerebral Injury ◽  
Future Research ◽  
Mortality And Morbidity ◽  
The Central Nervous System ◽  
The Brain

Aneurysms and vascular malformations of the brain represent an important source of intracranial hemorrhage and subsequent mortality and morbidity. We are only beginning to discern the involvement of microglia, the resident immune cell of the central nervous system, in these pathologies and their outcomes. Recent evidence suggests that activated proinflammatory microglia are implicated in the expansion of brain injury following subarachnoid hemorrhage (SAH) in both the acute and chronic phases, being also a main actor in vasospasm, considerably the most severe complication of SAH. On the other hand, anti-inflammatory microglia may be involved in the resolution of cerebral injury and hemorrhage. These immune cells have also been observed in high numbers in brain arteriovenous malformations (bAVM) and cerebral cavernomas (CCM), although their roles in these lesions are currently incompletely ascertained. The following review aims to shed a light on the most significant findings related to microglia and their roles in intracranial aneurysms and vascular malformations, as well as possibly establish the course for future research.

THE ORIGINS OF MUSIC: INNATENESS, UNIQUENESS, AND EVOLUTION

2005 ◽  
Vol 23 (1) ◽  
pp. 29-59 ◽  
Author(s):  
JOSH McDERMOTT ◽  
MARC HAUSER
Keyword(s):  
Side Effects ◽  
Music Perception ◽  
Comparative Psychology ◽  
General Purpose ◽  
Adaptive Significance ◽  
Future Research ◽  
Relative Pitch ◽  
The Past ◽  
Evolution Of Music ◽  
Basic Features

THE ORIGINS and adaptive significance of music, long an elusive target, are now active topics of empirical study, with many interesting developments over the past few years. This article reviews research in anthropology, ethnomusicology, developmental and comparative psychology, neuropsychology, and neurophysiology that bears on questions concerning the origins and evolution of music. We focus on the hypothesis that music perception is constrained by innate, possibly human- and musicspecific principles of organization, as these are candidates for evolutionary explanations. We begin by discussing the distinct roles of different fields of inquiry in constraining claims about innateness and adaptation, and then proceed to review the available evidence. Although research on many of these topics is still in its infancy, at present there is converging evidence that a few basic features of music (relative pitch, the importance of the octave, intervals with simple ratios, tonality, and perhaps elementary musical preferences) are determined in part by innate constraints. At present, it is unclear how many of these constraints are uniquely human and specific to music. Many, however, are unlikely to be adaptations for music, but rather are probably side effects of more general-purpose mechanisms. We conclude by reiterating the significance of identifying processes that are innate, unique to humans, and specific to music, and highlight several possible directions for future research.

A Theoretical Basis for Emergent Pattern Discrimination in Neural Systems Through Slow Feature Extraction

2010 ◽  
Vol 22 (12) ◽  
pp. 2979-3035 ◽  
Author(s):  
Stefan Klampfl ◽  
Wolfgang Maass
Keyword(s):  
Feature Extraction ◽  
Theoretical Basis ◽  
Learning Algorithm ◽  
Temporal Cortex ◽  
Pattern Discrimination ◽  
Stimulus Onset ◽  
Inferior Temporal Cortex ◽  
Linear Discriminant ◽  
Discrimination Capability ◽  
The Brain

Neurons in the brain are able to detect and discriminate salient spatiotemporal patterns in the firing activity of presynaptic neurons. It is open how they can learn to achieve this, especially without the help of a supervisor. We show that a well-known unsupervised learning algorithm for linear neurons, slow feature analysis (SFA), is able to acquire the discrimination capability of one of the best algorithms for supervised linear discrimination learning, the Fisher linear discriminant (FLD), given suitable input statistics. We demonstrate the power of this principle by showing that it enables readout neurons from simulated cortical microcircuits to learn without any supervision to discriminate between spoken digits and to detect repeated firing patterns that are embedded into a stream of noise spike trains with the same firing statistics. Both these computer simulations and our theoretical analysis show that slow feature extraction enables neurons to extract and collect information that is spread out over a trajectory of firing states that lasts several hundred ms. In addition, it enables neurons to learn without supervision to keep track of time (relative to a stimulus onset, or the initiation of a motor response). Hence, these results elucidate how the brain could compute with trajectories of firing states rather than only with fixed point attractors. It also provides a theoretical basis for understanding recent experimental results on the emergence of view- and position-invariant classification of visual objects in inferior temporal cortex.

Coding of Temporally Varying Signals in Networks of Spiking Neurons with Global Delayed Feedback

2005 ◽  
Vol 17 (10) ◽  
pp. 2139-2175 ◽  
Author(s):  
Naoki Masuda ◽  
Brent Doiron ◽  
André Longtin ◽  
Kazuyuki Aihara
Keyword(s):  
Information Processing ◽  
Stimulus Frequency ◽  
Spiking Neurons ◽  
Feedforward Networks ◽  
Dynamical Characteristics ◽  
Neural Activities ◽  
Inherent Frequency ◽  
Types Of Information ◽  
The Brain

Oscillatory and synchronized neural activities are commonly found in the brain, and evidence suggests that many of them are caused by global feedback. Their mechanisms and roles in information processing have been discussed often using purely feedforward networks or recurrent networks with constant inputs. On the other hand, real recurrent neural networks are abundant and continually receive information-rich inputs from the outside environment or other parts of the brain. We examine how feedforward networks of spiking neurons with delayed global feedback process information about temporally changing inputs. We show that the network behavior is more synchronous as well as more correlated with and phase-locked to the stimulus when the stimulus frequency is resonant with the inherent frequency of the neuron or that of the network oscillation generated by the feedback architecture. The two eigenmodes have distinct dynamical characteristics, which are supported by numerical simulations and by analytical arguments based on frequency response and bifurcation theory. This distinction is similar to the class I versus class II classification of single neurons according to the bifurcation from quiescence to periodic firing, and the two modes depend differently on system parameters. These two mechanisms may be associated with different types of information processing.

Priors and Prejudice: How prior knowledge shapes intergroup perception

2021 ◽  
Author(s):  
Hugh McGovern ◽  
Marte Otten
Keyword(s):  
Social Psychology ◽  
Prior Knowledge ◽  
Cognitive Processes ◽  
Social Neuroscience ◽  
Intergroup Bias ◽  
Predictive Processing ◽  
Future Research ◽  
Intergroup Perception ◽  
The Brain ◽  
Processing Framework

Bayesian processing has become a popular framework by which to understand cognitive processes. However, relatively little has been done to understand how Bayesian processing in the brain can be applied to understanding intergroup cognition. We assess how categorization and evaluation processes unfold based on priors about the ethnic outgroup being perceived. We then consider how the precision of prior knowledge about groups differentially influence perception depending on how the information about that group was learned affects the way in which it is recalled. Finally, we evaluate the mechanisms of how humans learn information about other ethnic groups and assess how the method of learning influences future intergroup perception. We suggest that a predictive processing framework for assessing prejudice could help accounting for seemingly disparate findings on intergroup bias from social neuroscience, social psychology, and evolutionary psychology. Such an integration has important implications for future research on prejudice at the interpersonal, intergroup, and societal levels.

The Advancement of Neuroimaging Research Investigating Developmental Stuttering

2011 ◽  
Vol 21 (3) ◽  
pp. 88-95 ◽  
Author(s):  
Deryk S. Beal
Keyword(s):  
Speech Production ◽  
Fast Rate ◽  
Neural Correlates ◽  
Future Research ◽  
Current State ◽  
Developmental Stuttering ◽  
The Brain ◽  
State Of The Field

We are amassing information about the role of the brain in speech production and the potential neural limitations that coincide with developmental stuttering at a fast rate. As such, it is difficult for many clinician-scientists who are interested in the neural correlates of stuttering to stay informed of the current state of the field. In this paper, I aim to inspire clinician-scientists to tackle hypothesis-driven research that is grounded in neurobiological theory. To this end, I will review the neuroanatomical structures, and their functions, which are implicated in speech production and then describe the relevant differences identified in these structures in people who stutter relative to their fluently speaking peers. I will conclude the paper with suggestions on directions of future research to facilitate the evolution of the field of neuroimaging of stuttering.

Sequential Stereotype Priming: A Meta-Analysis

2017 ◽  
Vol 22 (3) ◽  
pp. 199-227 ◽  
Author(s):  
Ciara K. Kidder ◽  
Katherine R. White ◽  
Michelle R. Hinojos ◽  
Mayra Sandoval ◽  
Stephen L. Crites
Keyword(s):  
Meta Analysis ◽  
Stimulus Onset ◽  
Future Research ◽  
Implicit Measures ◽  
Methodological Rigor ◽  
Priming Paradigm ◽  
Type Data ◽  
Onset Asynchrony ◽  
Stereotype Priming ◽  
Explicit Measures

Psychological interest in stereotype measurement has spanned nearly a century, with researchers adopting implicit measures in the 1980s to complement explicit measures. One of the most frequently used implicit measures of stereotypes is the sequential priming paradigm. The current meta-analysis examines stereotype priming, focusing specifically on this paradigm. To contribute to ongoing discussions regarding methodological rigor in social psychology, one primary goal was to identify methodological moderators of the stereotype priming effect—whether priming is due to a relation between the prime and target stimuli, the prime and target response, participant task, stereotype dimension, stimulus onset asynchrony (SOA), and stimuli type. Data from 39 studies yielded 87 individual effect sizes from 5,497 participants. Analyses revealed that stereotype priming is significantly moderated by the presence of prime–response relations, participant task, stereotype dimension, target stimulus type, SOA, and prime repetition. These results carry both practical and theoretical implications for future research on stereotype priming.

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