A stable population code for attention in prefrontal cortex leads a dynamic attention code in visual cortex

2021 ◽  
pp. JN-RM-0608-21
Author(s):  
Adam C. Snyder ◽  
Byron M. Yu ◽  
Matthew A. Smith
2020 ◽  
Author(s):  
Yaelan Jung ◽  
Dirk B. Walther

AbstractNatural scenes deliver rich sensory information about the world. Decades of research has shown that the scene-selective network in the visual cortex represents various aspects of scenes. It is, however, unknown how such complex scene information is processed beyond the visual cortex, such as in the prefrontal cortex. It is also unknown how task context impacts the process of scene perception, modulating which scene content is represented in the brain. In this study, we investigate these questions using scene images from four natural scene categories, which also depict two types of global scene properties, temperature (warm or cold), and sound-level (noisy or quiet). A group of healthy human subjects from both sexes participated in the present study using fMRI. In the study, participants viewed scene images under two different task conditions; temperature judgment and sound-level judgment. We analyzed how different scene attributes (scene categories, temperature, and sound-level information) are represented across the brain under these task conditions. Our findings show that global scene properties are only represented in the brain, especially in the prefrontal cortex, when they are task-relevant. However, scene categories are represented in the brain, in both the parahippocampal place area and the prefrontal cortex, regardless of task context. These findings suggest that the prefrontal cortex selectively represents scene content according to task demands, but this task selectivity depends on the types of scene content; task modulates neural representations of global scene properties but not of scene categories.


2021 ◽  
pp. 118-152
Author(s):  
Richard E. Passingham

The orbital prefrontal cortex (PF) receives inputs from the olfactory, gustatory, somatosensory, visceral, and visual cortex. It is also interconnected with the amygdala which represents the current value of the resources, given the internal state of the animal. The worth of the different foods is compared in a ‘common currency’ of value. The central sector of the orbital prefrontal cortex uses vision to predict the value of the resources. These changes depend on the extent to which the animal has already become satiated on a particular food, and an interaction between the amygdala and the orbital PF cortex supports the ability to choose a new food, rather than the one on which the animal has become satiated. The lateral sector of the orbital PF cortex supports the ability to change behaviour depending on the outcome.


2016 ◽  
Vol 114 (2) ◽  
pp. 394-399 ◽  
Author(s):  
John D. Murray ◽  
Alberto Bernacchia ◽  
Nicholas A. Roy ◽  
Christos Constantinidis ◽  
Ranulfo Romo ◽  
...  

Working memory (WM) is a cognitive function for temporary maintenance and manipulation of information, which requires conversion of stimulus-driven signals into internal representations that are maintained across seconds-long mnemonic delays. Within primate prefrontal cortex (PFC), a critical node of the brain’s WM network, neurons show stimulus-selective persistent activity during WM, but many of them exhibit strong temporal dynamics and heterogeneity, raising the questions of whether, and how, neuronal populations in PFC maintain stable mnemonic representations of stimuli during WM. Here we show that despite complex and heterogeneous temporal dynamics in single-neuron activity, PFC activity is endowed with a population-level coding of the mnemonic stimulus that is stable and robust throughout WM maintenance. We applied population-level analyses to hundreds of recorded single neurons from lateral PFC of monkeys performing two seminal tasks that demand parametric WM: oculomotor delayed response and vibrotactile delayed discrimination. We found that the high-dimensional state space of PFC population activity contains a low-dimensional subspace in which stimulus representations are stable across time during the cue and delay epochs, enabling robust and generalizable decoding compared with time-optimized subspaces. To explore potential mechanisms, we applied these same population-level analyses to theoretical neural circuit models of WM activity. Three previously proposed models failed to capture the key population-level features observed empirically. We propose network connectivity properties, implemented in a linear network model, which can underlie these features. This work uncovers stable population-level WM representations in PFC, despite strong temporal neural dynamics, thereby providing insights into neural circuit mechanisms supporting WM.


Neuron ◽  
2003 ◽  
Vol 40 (1) ◽  
pp. 177-188 ◽  
Author(s):  
E.H. Baeg ◽  
Y.B. Kim ◽  
K. Huh ◽  
I. Mook-Jung ◽  
H.T. Kim ◽  
...  

Author(s):  
Richard Johnston ◽  
Adam C. Snyder ◽  
Sanjeev B. Khanna ◽  
Deepa Issar ◽  
Matthew A. Smith

SummaryDecades of research have shown that global brain states such as arousal can be indexed by measuring the properties of the eyes. Neural signals from individual neurons, populations of neurons, and field potentials measured throughout much of the brain have been associated with the size of the pupil, small fixational eye movements, and vigor in saccadic eye movements. However, precisely because the eyes have been associated with modulation of neural activity across the brain, and many different kinds of measurements of the eyes have been made across studies, it has been difficult to clearly isolate how internal states affect the behavior of the eyes, and vice versa. Recent work in our laboratory identified a latent dimension of neural activity in macaque visual cortex on the timescale of minutes to tens of minutes. This ‘slow drift’ was associated with perceptual performance on an orientation-change detection task, as well as neural activity in visual and prefrontal cortex (PFC), suggesting it might reflect a shift in a global brain state. This motivated us to ask if the neural signature of this internal state is correlated with the action of the eyes in different behavioral tasks. We recorded from visual cortex (V4) while monkeys performed a change detection task, and the prefrontal cortex, while they performed a memory-guided saccade task. On both tasks, slow drift was associated with a pattern that is indicative of changes in arousal level over time. When pupil size was large, and the subjects were in a heighted state of arousal, microsaccade rate and reaction time decreased while saccade velocity increased. These results show that the action of the eyes is associated with a dominant mode of neural activity that is pervasive and task-independent, and can be accessed in the population activity of neurons across the cortex.


2021 ◽  
Author(s):  
Matan Mazor ◽  
Nadine Dijkstra ◽  
Stephen M Fleming

A key goal of consciousness science is identifying neural signatures of being aware vs. unaware of simple stimuli. This is often investigated in the context of near-threshold detection, with reports of stimulus awareness being linked to heightened activation in a frontoparietal network. However, due to the fact that reports of stimulus presence are also associated with higher confidence than reports of stimulus absence, these results could be explained by frontoparietal regions encoding stimulus visibility, decision confidence or both. Consistent with this view, previously we showed that prefrontal regions encode confidence in decisions about target presence (Mazor, Friston & Fleming, 2020). Here, we further ask if prefrontal cortex also encodes information about stimulus visibility over and above confidence. We first show that, whereas stimulus identity was best decoded from the visual cortex, stimulus visibility (presence vs. absence) was best decoded from prefrontal regions. To control for effects of confidence, we then selectively sampled trials prior to decoding to equalize the confidence distributions between absence and presence responses. This analysis revealed that posterior medial frontal cortex encoded stimulus visibility over and above decision confidence. We interpret our findings as providing support for a representation of stimulus visibility in specific higher-order cortical circuits, one that is dissociable from representations of both decision confidence and stimulus identity.


Cell Reports ◽  
2020 ◽  
Vol 33 (6) ◽  
pp. 108367
Author(s):  
Veronika Koren ◽  
Ariana R. Andrei ◽  
Ming Hu ◽  
Valentin Dragoi ◽  
Klaus Obermayer

Neuroscience ◽  
2014 ◽  
Vol 274 ◽  
pp. 33-43 ◽  
Author(s):  
M.E. Young ◽  
D.T. Ohm ◽  
D. Dumitriu ◽  
P.R. Rapp ◽  
J.H. Morrison

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