The geometry of abstraction in hippocampus and pre-frontal cortex

The curse of dimensionality plagues models of reinforcement learning and decision-making. The process of abstraction solves this by constructing abstract variables describing features shared by different specific instances, reducing dimensionality and enabling generalization in novel situations. Here we characterized neural representations in monkeys performing a task where a hidden variable described the temporal statistics of stimulus-response-outcome mappings. Abstraction was defined operationally using the generalization performance of neural decoders across task conditions not used for training. This type of generalization requires a particular geometric format of neural representations. Neural ensembles in dorsolateral pre-frontal cortex, anterior cingulate cortex and hippocampus, and in simulated neural networks, simultaneously represented multiple hidden and explicit variables in a format reflecting abstraction. Task events engaging cognitive operations modulated this format. These findings elucidate how the brain and artificial systems represent abstract variables, variables critical for generalization that in turn confers cognitive flexibility.

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Task dependence of neural representations of global scene properties but not scene categories in the prefrontal cortex

10.1101/2020.12.04.412445 ◽

2020 ◽

Author(s):

Yaelan Jung ◽

Dirk B. Walther

Keyword(s):

Prefrontal Cortex ◽

Visual Cortex ◽

Scene Perception ◽

Sound Level ◽

Task Context ◽

Complex Scene ◽

Neural Representations ◽

Task Conditions ◽

Scene Content ◽

The Brain

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.

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Hierarchical reasoning by neural circuits in the frontal cortex

Science ◽

10.1126/science.aav8911 ◽

2019 ◽

Vol 364 (6441) ◽

pp. eaav8911 ◽

Cited By ~ 23

Author(s):

Morteza Sarafyazd ◽

Mehrdad Jazayeri

Keyword(s):

Frontal Cortex ◽

Neural Circuits ◽

Anterior Cingulate ◽

Cortical Circuits ◽

Neural Basis ◽

Stimulus Response ◽

Response Contingency ◽

Dorsomedial Frontal Cortex ◽

Reasoning Strategy ◽

Additional Perturbation

Humans process information hierarchically. In the presence of hierarchies, sources of failures are ambiguous. Humans resolve this ambiguity by assessing their confidence after one or more attempts. To understand the neural basis of this reasoning strategy, we recorded from dorsomedial frontal cortex (DMFC) and anterior cingulate cortex (ACC) of monkeys in a task in which negative outcomes were caused either by misjudging the stimulus or by a covert switch between two stimulus-response contingency rules. We found that both areas harbored a representation of evidence supporting a rule switch. Additional perturbation experiments revealed that ACC functioned downstream of DMFC and was directly and specifically involved in inferring covert rule switches. These results‏ reveal the computational principles of hierarchical reasoning, as implemented by cortical circuits.

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Shared neural representations of cognitive conflict and negative affect in the medial frontal cortex

10.1101/824839 ◽

2019 ◽

Cited By ~ 1

Author(s):

Luc Vermeylen ◽

David Wisniewski ◽

Carlos González-García ◽

Vincent Hoofs ◽

Wim Notebaert ◽

...

Keyword(s):

Negative Affect ◽

Frontal Cortex ◽

Supplementary Motor Area ◽

Cognitive Conflict ◽

Medial Frontal Cortex ◽

Anterior Cingulate ◽

Dorsal Anterior Cingulate Cortex ◽

Neural Representations ◽

Fmri Study ◽

Multivariate Pattern

AbstractInfluential theories of medial frontal cortex (MFC) function suggest that the MFC registers cognitive conflict as an aversive signal, but no study directly tested this idea. Instead, recent studies suggested that non-overlapping regions in the MFC process conflict and affect. In this pre-registered human fMRI study, we used multivariate pattern analyses to identify which regions respond similarly to conflict and aversive signals. The results reveal that, of all conflict- and value-related regions, the ventral pre-supplementary motor area (or dorsal anterior cingulate cortex) showed a shared neural pattern response to different conflict and affect tasks. These findings challenge recent conclusions that conflict and affect are processed independently, and provide support for integrative views of MFC function.

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Neural Responses in Dorsal Prefrontal Cortex Reflect Proactive Interference during an Auditory Reversal Task

10.1101/354936 ◽

2018 ◽

Author(s):

Nikolas A. Francis ◽

Susanne Radtke-Schuller ◽

Jonathan B. Fritz ◽

Shihab A. Shamma

Keyword(s):

Prefrontal Cortex ◽

Frontal Cortex ◽

Proactive Interference ◽

Cognitive Flexibility ◽

Neural Activity ◽

Neural Correlates ◽

Neural Responses ◽

Reversal Task ◽

Neural Correlate ◽

The Brain

AbstractTask-related plasticity in the brain is triggered by changes in the behavioral meaning of sounds. We investigated plasticity in ferret dorsolateral frontal cortex (dlFC) during an auditory reversal task to study the neural correlates of proactive interference, i.e., perseveration of previously learned behavioral meanings that are no longer task-appropriate. Although the animals learned the task, target recognition decreased after reversals, indicating proactive interference. Frontal cortex responsiveness was consistent with previous findings that dlFC encodes the behavioral meaning of sounds. However, the neural responses observed here were more complex. For example, target responses were strongly enhanced, while responses to non-target tones and noises were weakly enhanced and strongly suppressed, respectively. Moreover, dlFC responsiveness reflected the proactive interference observed in behavior: target responses decreased after reversals, most significantly during incorrect behavioral responses. These findings suggest that the weak representation of behavioral meaning in dlFC may be a neural correlate of proactive interference.Significance StatementNeural activity in prefrontal cortex (PFC) is believed to enable cognitive flexibility during sensory-guided behavior. Since PFC encodes the behavioral meaning of sensory events, we hypothesized that weak representation of behavioral meaning in PFC may limit cognitive flexibility. To test this hypothesis, we recorded neural activity in ferret PFC, while ferrets performed an auditory reversal task in which the behavioral meanings of sounds were reversed during experiments. The reversal task enabled us study PFC responses during proactive interference, i.e. perseveration of previously learned behavioral meanings that are no longer task-appropriate. We found that task performance errors increased after reversals while PFC representation of behavioral meaning diminished. Our findings suggest that proactive interference may occur when PFC forms weak sensory-cognitive associations.

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Rule adherence warps decision-making

10.1101/2019.12.16.878306 ◽

2019 ◽

Cited By ~ 1

Author(s):

R. Becket Ebitz ◽

Jiaxin Cindy Tu ◽

Benjamin Y. Hayden

Keyword(s):

Decision Making ◽

Dorsal Striatum ◽

Neuronal Firing ◽

Energetic Cost ◽

Processing Efficiency ◽

Rule Based ◽

Stimulus Response ◽

Neural Representations ◽

Sensorimotor Information ◽

The Brain

ABSTRACTWe have the capacity to follow arbitrary stimulus-response rules, meaning policies that determine how we will behave across circumstances. Yet, it is not clear how rules guide sensorimotor decision-making in the brain. Here, we recorded from neurons in three regions linked to decision-making, the orbitofrontal cortex, ventral striatum, and dorsal striatum, while macaques performed a rule-based decision-making task. We found that different rules warped the neural representations of chosen options by expanding rule-relevant coding dimensions relative to rule-irrelevant ones. Some cognitive theories suggest that warping could increase processing efficiency by facilitating rule-relevant computations at the expense of irrelevant ones. To test this idea, we modeled rules as the latent causes of decisions and identified a set of “rule-free” choices that could not be explained by simple rules. Contrasting these with rule-based choices revealed that following rules decreased the energetic cost of decision-making while warping the representational geometry of choice.SIGNIFICANCE STATEMENTOne important part of our ability to adapt flexibly to the world around us is our ability to implement arbitrary stimulus-response mappings, known as “rules”. Many studies have shown that when we follow a rule, its identity is encoded in neuronal firing rates. However, it remains unclear how rules regulate behavior. Here, we report that rules warp the way that sensorimotor information is represented in decision-making circuits: enhancing information that is relevant to the current rule at the expense of information that is irrelevant. These results imply that rules are implemented as a kind of attentional gate on what information is available for decision-making.

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Distinct neural representations for prosocial and self-benefitting effort

10.1101/2021.09.27.461936 ◽

2021 ◽

Author(s):

Patricia Lockwood ◽

Marco Wittmann ◽

Hamed Nili ◽

Mona Matsumoto-Ryan ◽

Ayat Abdurahman ◽

...

Keyword(s):

Univariate Analysis ◽

Well Being ◽

Anterior Cingulate ◽

Anterior Cingulate Gyrus ◽

Brain Areas ◽

Neural Representations ◽

Subjective Value ◽

Neural Signature ◽

Prosocial Behaviours ◽

The Brain

Prosocial behaviours - actions that benefit others - are central to individual and societal well-being. Most prosocial acts are effortful. Yet, how the brain encodes effort costs when actions benefit others is unknown. Here, using a combination of multivariate representational similarity analysis and model-based univariate analysis during fMRI, we reveal how the costs of prosocial efforts are processed. Strikingly, we identified a unique neural signature of effort in the anterior cingulate gyrus for prosocial acts both when choosing to help others and when exerting force for their benefit. This pattern was absent for similar self-benefitting behaviour and correlated with individual levels of empathy. In contrast, the ventral tegmental area and the ventral insula signalled subjective value preferentially when choosing whether to exert effort to benefit oneself. These findings demonstrate partially distinct brain areas guide the evaluation and exertion of effort costs when acts are prosocial or self-benefitting.

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Mapping a cognitive theory onto neurology

10.31234/osf.io/9mbuv ◽

2021 ◽

Author(s):

Lorin Friesen

Keyword(s):

Frontal Cortex ◽

Left Hemisphere ◽

Cognitive Theory ◽

Right Hemisphere ◽

Cognitive Styles ◽

Brain Regions ◽

The Other ◽

Anterior Cingulate ◽

The Right ◽

The Brain

Neurological research has made amazing strides in recent years. Enough is now known about what specific brain areas do to make it possible to start examining how various parts of the brain interact. What is missing is a general theory of cognition to tie all of this information together. Back in the 1980s, a cognitive theory was developed that began with a system of cognitive styles and was expanded through an in-depth study of biographies. It was discovered at that time that this theory mapped in a general way onto the brain. This cognitive theory, known as the theory of mental symmetry, has recently been tested as a meta-theory by using it to analyze a number of fields and theories dealing with human thought and behavior. This paper shows that personality traits that were discovered by mental symmetry correspond in detail to the functioning of brain regions described in current neurological papers. In brief, the cognitive model suggests that there are seven cognitive styles: There are four simple styles, and there are three composite styles that combine the thinking of the simple styles. Two of the simple styles use emotions and emphasize a circuit composed of orbitofrontal cortex, inferior frontal cortex, temporal lobe, and amygdala, with one in the left hemisphere and the other in the right hemisphere. The other two simple styles use confidence and emphasize a circuit consisting of dorsolateral frontal cortex, frontopolar cortex, parietal cortex, and hippocampus, again with one in the left hemisphere and the other in the right hemisphere. The three composite styles form a processing chain. The first composite style combines the two simple emotional styles and emphasizes the ventral striatum, and dopamine. This leads to the second composite style, which combines the two simple confidence styles and emphasizes the anterior cingulate, the dorsal striatum, and serotonin. This is followed by the third composite style which balances the functioning of the mind and emphasizes the thalamus and noradrenaline.

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