scholarly journals Evidence accumulation relates to perceptual consciousness and monitoring

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Pereira ◽  
Pierre Megevand ◽  
Mi Xue Tan ◽  
Wenwen Chang ◽  
Shuo Wang ◽  
...  

AbstractA fundamental scientific question concerns the neural basis of perceptual consciousness and perceptual monitoring resulting from the processing of sensory events. Although recent studies identified neurons reflecting stimulus visibility, their functional role remains unknown. Here, we show that perceptual consciousness and monitoring involve evidence accumulation. We recorded single-neuron activity in a participant with a microelectrode in the posterior parietal cortex, while they detected vibrotactile stimuli around detection threshold and provided confidence estimates. We find that detected stimuli elicited neuronal responses resembling evidence accumulation during decision-making, irrespective of motor confounds or task demands. We generalize these findings in healthy volunteers using electroencephalography. Behavioral and neural responses are reproduced with a computational model considering a stimulus as detected if accumulated evidence reaches a bound, and confidence as the distance between maximal evidence and that bound. We conclude that gradual changes in neuronal dynamics during evidence accumulation relates to perceptual consciousness and perceptual monitoring in humans.

Author(s):  
Michael Pereira ◽  
Pierre Megevand ◽  
Mi Xue Tan ◽  
Wenwen Chang ◽  
Shuo Wang ◽  
...  

A fundamental scientific question concerns the neuronal basis of perceptual consciousness, which encompasses the perceptual experience and reflexive monitoring associated with a sensory event. Although recent human studies identified individual neurons reflecting stimulus visibility, their functional role for perceptual consciousness remains unknown. Here, we provide neuronal and computational evidence indicating that perceptual and reflexive consciousness are governed by an all-or-none process involving accumulation of perceptual evidence. We recorded single-neuron activity in a participant with a microelectrode implant in the posterior parietal cortex, considered a substrate for evidence accumulation, while he detected vibrotactile stimuli around detection threshold and provided confidence estimates. We found that detected stimuli elicited firing rate patterns resembling evidence accumulation during decision-making, irrespective of response effectors. Similar neurons encoded the intensity of task-irrelevant stimuli, suggesting their role for consciousness per se, irrespective of report. We generalized these findings in healthy volunteers using electroencephalography and reproduced their behavioral and neural responses with a computational model. This model considered stimulus detection if accumulated evidence reached a bound, and confidence as the distance between maximal evidence and that bound. Applying this mechanism to our neuronal data, we were able to decode single-trial confidence ratings both for detected and undetected stimuli. Our results show that the specific gradual changes in neuronal dynamics during evidence accumulation govern perceptual consciousness and reflexive monitoring in humans.


Author(s):  
Jacinta OʼShea ◽  
Matthew F. S. Rushworth

This article reviews the contribution of transcranial magnetic stimulation (TMS) research to the understanding of attention, eye movements, visual search, and neglect. It considers how TMS studies have confirmed, refined, or challenged prevailing ideas about the neural basis of higher visual cognition. It shows that TMS has enhanced the understanding of the location, timing, and functional roles of visual cognitive processes in the human brain. The main focus is on studies of posterior parietal cortex (PPC), with reference to recent work on the frontal eye fields (FEFs). TMS offers many advantages to complement neuropsychological patient studies to enhance the understanding of how the fronto-parietal cortical nerves function. The visuo-spatial neglect- and extinction-like deficits incurred by parietal damage have been modelled successfully using TMS. Future work might be directed at teasing apart the distinct functional roles of nodes within this frontoparietal network in different sensorimotor contexts.


2015 ◽  
Vol 27 (2) ◽  
pp. 377-386 ◽  
Author(s):  
Dario Cazzoli ◽  
René M. Müri ◽  
Christopher Kennard ◽  
Clive R. Rosenthal

When briefly presented with pairs of words, skilled readers can sometimes report words with migrated letters (e.g., they report hunt when presented with the words hint and hurt). This and other letter migration phenomena have been often used to investigate factors that influence reading such as letter position coding. However, the neural basis of letter migration is poorly understood. Previous evidence has implicated the right posterior parietal cortex (PPC) in processing visuospatial attributes and lexical properties during word reading. The aim of this study was to assess this putative role by combining an inhibitory TMS protocol with a letter migration paradigm, which was designed to examine the contributions of visuospatial attributes and lexical factors. Temporary interference with the right PPC led to three specific effects on letter migration. First, the number of letter migrations was significantly increased only in the group with active stimulation (vs. a sham stimulation group or a control group without stimulation), and there was no significant effect on other error types. Second, this effect occurred only when letter migration could result in a meaningful word (migration vs. control context). Third, the effect of active stimulation on the number of letter migrations was lateralized to target words presented on the left. Our study thus demonstrates that the right PPC plays a specific and causal role in the phenomenon of letter migration. The nature of this role cannot be explained solely in terms of visuospatial attention, rather it involves an interplay between visuospatial attentional and word reading-specific factors.


eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Jeffrey C Erlich ◽  
Bingni W Brunton ◽  
Chunyu A Duan ◽  
Timothy D Hanks ◽  
Carlos D Brody

Numerous brain regions have been shown to have neural correlates of gradually accumulating evidence for decision-making, but the causal roles of these regions in decisions driven by accumulation of evidence have yet to be determined. Here, in rats performing an auditory evidence accumulation task, we inactivated the frontal orienting fields (FOF) and posterior parietal cortex (PPC), two rat cortical regions that have neural correlates of accumulating evidence and that have been proposed as central to decision-making. We used a detailed model of the decision process to analyze the effect of inactivations. Inactivation of the FOF induced substantial performance impairments that were quantitatively best described as an impairment in the output pathway of an evidence accumulator with a long integration time constant (>240 ms). In contrast, we found a minimal role for PPC in decisions guided by accumulating auditory evidence, even while finding a strong role for PPC in internally-guided decisions.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Michael M Yartsev ◽  
Timothy D Hanks ◽  
Alice Misun Yoon ◽  
Carlos D Brody

A broad range of decision-making processes involve gradual accumulation of evidence over time, but the neural circuits responsible for this computation are not yet established. Recent data indicate that cortical regions that are prominently associated with accumulating evidence, such as the posterior parietal cortex and the frontal orienting fields, may not be directly involved in this computation. Which, then, are the regions involved? Regions that are directly involved in evidence accumulation should directly influence the accumulation-based decision-making behavior, have a graded neural encoding of accumulated evidence and contribute throughout the accumulation process. Here, we investigated the role of the anterior dorsal striatum (ADS) in a rodent auditory evidence accumulation task using a combination of behavioral, pharmacological, optogenetic, electrophysiological and computational approaches. We find that the ADS is the first brain region known to satisfy the three criteria. Thus, the ADS may be the first identified node in the network responsible for evidence accumulation.


2019 ◽  
Author(s):  
Tuce Tombaz ◽  
Benjamin A. Dunn ◽  
Karoline Hovde ◽  
Ryan J. Cubero ◽  
Bartul Mimica ◽  
...  

AbstractThe posterior parietal cortex (PPC), along with anatomically linked frontal areas, form a cortical network which mediates several functions that support goal-directed behavior, including sensorimotor transformations and decision making. In primates, this network also links performed and observed actions via mirror neurons, which fire both when an individual performs an action and when they observe the same action performed by a conspecific. Mirror neurons are thought to be important for social learning and imitation, but it is not known whether mirror-like neurons occur in similar networks in other species that can learn socially, such as rodents. We therefore imaged Ca2+ responses in large neural ensembles in PPC and secondary motor cortex (M2) while mice performed and observed several actions in pellet reaching and wheel running tasks. In all animals, we found spatially overlapping neural ensembles in PPC and M2 that robustly encoded a variety of naturalistic behaviors, and that subsets of cells could stably encode multiple actions. However, neural responses to the same set of observed actions were absent in both brain areas, and across animals. Statistical modeling analyses also showed that performed actions, especially those that were task-specific, outperformed observed actions in predicting neural responses. Overall, these findings show that performed and observed actions do not drive the same cells in the parieto-frontal network in mice, and suggest that sensorimotor mirroring in the mammalian cortex may have evolved more recently, and only in certain species.


1994 ◽  
Vol 72 (2) ◽  
pp. 1020-1023 ◽  
Author(s):  
M. A. Steinmetz ◽  
C. E. Connor ◽  
C. Constantinidis ◽  
J. R. McLaughlin

1. The effect of covert attention was studied in area 7a of the posterior parietal cortex of rhesus monkeys performing a spatial match-to-sample task. The task required the animals to fixate a central target light, to detect and remember the location of a transient spatial cue, and to respond when one of a series of stimuli appeared at the cued location. Neuronal responses evoked by the visual stimuli were recorded during each behavioral trial. 2. Thirty-eight percent of the neurons isolated and studied in these experiments responded to visual stimuli. The responses of 55% of the neurons tested were suppressed, and 5% enhanced for stimuli presented at the attended location. Responses in the remaining neurons (40%) were unaffected by shifts in attention. 3. Activity in 57% of the suppressed neurons was reduced to rates not significantly different from spontaneous activity. 4. The extent of suppression for individual neurons was often restricted to the attended portion of the receptive field. 5. These data suggest a potential role for these neurons in the redirection of visual attention.


2014 ◽  
Author(s):  
Jeffrey C Erlich ◽  
Bingni W Brunton ◽  
Chunyu A Duan ◽  
Timothy D Hanks ◽  
Carlos D Brody

Numerous brain regions have been shown to have neural correlates of gradually accumulating evidence for decision-making, but the causal roles of these regions in decisions driven by accumulation of evi- dence have yet to be determined. Here, in rats performing an auditory evidence accumulation task, we inactivated the frontal orienting fields (FOF) and posterior parietal cortex (PPC), two rat cortical regions that have neural correlates of accumulating evidence and that have been proposed as central to decision-making. We used a detailed model of the decision process to analyze the effect of inactivations. Inactivation of the FOF induced substantial performance impairments that were quantitatively best de- scribed as an impairment in the output pathway of an evidence accumulator with a long integration time constant (>240ms). In contrast, we found a minimal role for PPC in decisions guided by accumulating auditory evidence, even while finding a strong role for PPC in internally-guided decisions.


2021 ◽  
Vol 15 ◽  
Author(s):  
Makoto Wada ◽  
Kouji Takano ◽  
Masakazu Ide ◽  
Yoshitake Sano ◽  
Yo Shinoda ◽  
...  

Rubber hand illusion (RHI), a kind of body ownership illusion, is sometimes atypical in individuals with autism spectrum disorder; however, the brain regions associated with the illusion are still unclear. We previously reported that mice responded as if their own tails were being touched when rubber tails were grasped following synchronous stroking to rubber tails and their tails (a “rubber tail illusion”, RTI), which is a task based on the human RHI; furthermore, we reported that the RTI response was diminished in Ca2+-dependent activator protein for secretion 2-knockout (Caps2-KO) mice that exhibit autistic-like phenotypes. Importance of the posterior parietal cortex in the formation of illusory perception has previously been reported in human imaging studies. However, the local neural circuits and cell properties associated with this process are not clear. Therefore, we aimed to elucidate the neural basis of the RTI response and its impairment by investigating the c-Fos expression in both wild-type (WT) and Caps2-KO mice during the task since the c-Fos expression occurred soon after the neural activation. Immediately following the delivery of the synchronous stroking to both rubber tails and actual tails, the mice were perfused. Subsequently, whole brains were cryo-sectioned, and each section was immunostained with anti-c-Fos antibody; finally, c-Fos positive cell densities among the groups were compared. The c-Fos expression in the posterior parietal cortex was significantly lower in the Caps2-KO mice than in the WT mice. Additionally, we compared the c-Fos expression in the WT mice between synchronous and asynchronous conditions and found that the c-Fos-positive cell densities were significantly higher in the claustrum and primary somatosensory cortex of the WT mice exposed to the synchronous condition than those exposed to the asynchronous condition. Hence, the results suggest that decreased c-Fos expression in the posterior parietal cortex may be related to impaired multisensory integrations in Caps2-KO mice.


2021 ◽  
Author(s):  
Brian DePasquale ◽  
Jonathan W Pillow ◽  
Carlos Brody

Accumulating evidence in service of sensory decision making is a core cognitive function. However, previous work has focused either on the dynamics of neural activity during decision-making or on models of evidence accumulation governing behavior. We unify these two perspectives by introducing an evidence-accumulation framework that simultaneously describes multi-neuron population spiking activity and dynamic stimulus-driven behavior during sensory decision-making. We apply our method to behavioral choices and neural activity recorded from three brain regions - the posterior parietal cortex (PPC), the frontal orienting fields (FOF), and the anterior-dorsal striatum (ADS) - while rats performed a pulse-based accumulation task. The model accurately captures the relationship between stimuli and neural activity, the coordinated activity of neural populations, and the distribution of animal choices in response to the stimulus. Model fits show strikingly distinct accumulation models expressed within each brain region, and that all differ strongly from the accumulation strategy expressed at the level of choices. In particular, the FOF exhibited a suboptimal 'primacy' strategy, where early sensory evidence was favored. Including neural data in the model led to improved prediction of the moment-by-moment value of accumulated evidence and the intended-and ultimately made-choice of the animal. Our approach offers a window into the neural representation of accumulated evidence and provides a principled framework for incorporating neural responses into accumulation models.


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