scholarly journals Convolutional neural networks reveal topic-level representations of sentences in medial prefrontal cortex, lateral anterior temporal lobe, precuneus, and angular gyrus

2021 ◽  
Author(s):  
David Acunzo ◽  
Daniel Mark Low ◽  
scott fairhall
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Temporal Lobe ◽  
Brain Regions ◽  
Angular Gyrus ◽  
Anterior Temporal Lobe ◽  
Semantic Categories ◽  
Word Level ◽  
Sentence Level ◽  
Final Layer

When reading a sentence, individual words can be combined to create more complex meaning. In this study, we sought to uncover brain regions that reflect the representation of meaning at the sentence level, as opposed to only the meaning of their individual constituent words. Using fMRI, we recorded the neural activity of participants while reading sentences. We constructed sentence topic-level representations using the final layer of a convolutional neural network (CNN) trained to classify Wikipedia sentences into broad semantic categories. This model was contrasted with word-level sentence representations constructed using the average of the word embeddings constituting the sentence. Using representational similarity analysis, we found that the medial prefrontal cortex, lateral anterior temporal lobe, precuneus, and angular gyrus more strongly represent sentence topic-level, compared to word-level, meaning, uncovering the important role of these semantic system regions in the representation of integrated meaning. Conversely, these results validate the capacity of CNNs to capture human sentence-level representations.

scholarly journals Novel Inferences in a Multidimensional Social Network Use a Grid-like Code

2020 ◽  
Author(s):  
Seongmin A. Park ◽  
Douglas S. Miller ◽  
Erie D. Boorman
Keyword(s):  
Decision Making ◽  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Entorhinal Cortex ◽  
Brain Regions ◽  
Cognitive Map ◽  
General Mechanism ◽  
Temporoparietal Junction ◽  
Flexible Behavior ◽  
Discrete Problems

ABSTRACTGeneralizing experiences to guide decision making in novel situations is a hallmark of flexible behavior. It has been hypothesized such flexibility depends on a cognitive map of an environment or task, but directly linking the two has proven elusive. Here, we find that discretely sampled abstract relationships between entities in an unseen two-dimensional (2-D) social hierarchy are reconstructed into a unitary 2-D cognitive map in the hippocampus and entorhinal cortex. We further show that humans utilize a grid-like code in several brain regions, including entorhinal cortex and medial prefrontal cortex, for inferred direct trajectories between entities in the reconstructed abstract space during discrete decisions. Moreover, these neural grid-like codes in the entorhinal cortex predict neural decision value computations in the medial prefrontal cortex and temporoparietal junction area during choice. Collectively, these findings show that grid-like codes are used by the human brain to infer novel solutions, even in abstract and discrete problems, and suggest a general mechanism underpinning flexible decision making and generalization.

scholarly journals Neural correlates of integrated self and social processing

2020 ◽  
Vol 15 (9) ◽  
pp. 941-949
Author(s):  
Laura Finlayson-Short ◽  
Christopher G Davey ◽  
Ben J Harrison
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Processing Condition ◽  
Emotional Valence ◽  
Neural Correlates ◽  
Brain Regions ◽  
Affective Processing ◽  
Social Processing ◽  
Referential Processing ◽  
Core Self

Abstract Self-referential and social processing are often engaged concurrently in naturalistic judgements and elicit activity in overlapping brain regions. We have termed this integrated processing ‘self-other referential processing’ and developed a task to measure its neural correlates. Ninety-eight healthy young people aged 16–25 (M = 21.5 years old, 67% female) completed our novel functional magnetic resonance imaging task. The task had two conditions, an active self-other referential processing condition in which participants rated how much they related to emotional faces and a control condition. Rating relatedness required thinking about oneself (self-referential processing) and drawing a comparison to an imagined other (social processing). Self-other referential processing elicited activity in the default mode network and social cognition system; most notably in the ‘core self’ regions of the medial prefrontal cortex and posterior cingulate cortex. Relatedness and emotional valence directly modulated activity in these core self areas, while emotional valence additionally modulated medial prefrontal cortex activity. This shows the key role of the medial prefrontal cortex in constructing the ‘social-affective self’. This may help to unify disparate models of medial prefrontal cortex function, demonstrating its role in coordinating multiple processes—self-referential, social and affective processing—to allow the self to exist in a complex social world.

scholarly journals Large-scale functional coactivation patterns reflect the structural connectivity of the medial prefrontal cortex

2020 ◽  
Author(s):  
Dale T Tovar ◽  
Robert S Chavez
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Large Scale ◽  
Spatial Scales ◽  
Structural Connectivity ◽  
Brain Regions ◽  
Machine Learning Techniques ◽  
Affective Processing ◽  
Affective Neuroscience ◽  
Psychological Phenomena

Abstract The medial prefrontal cortex (MPFC) is among the most consistently implicated brain regions in social and affective neuroscience. Yet, this region is also highly functionally heterogeneous across many domains and has diverse patterns of connectivity. The extent to which the communication of functional networks in this area is facilitated by its underlying structural connectivity fingerprint is critical for understanding how psychological phenomena are represented within this region. In the current study, we combined diffusion magnetic resonance imaging and probabilistic tractography with large-scale meta-analysis to investigate the degree to which the functional co-activation patterns of the MPFC is reflected in its underlying structural connectivity. Using unsupervised machine learning techniques, we compared parcellations between the two modalities and found congruence between parcellations at multiple spatial scales. Additionally, using connectivity and coactivation similarity analyses, we found high correspondence in voxel-to-voxel similarity between each modality across most, but not all, subregions of the MPFC. These results provide evidence that meta-analytic functional coactivation patterns are meaningfully constrained by underlying neuroanatomical connectivity and provide convergent evidence of distinct subregions within the MPFC involved in affective processing and social cognition.

scholarly journals Constitutive Genetic Deletion of Hcn1 Increases Alcohol Preference during Adolescence

2020 ◽  
Vol 10 (11) ◽  
pp. 763
Author(s):  
Michael C. Salling ◽  
Neil L. Harrison
Keyword(s):  
Prefrontal Cortex ◽  
Alcohol Consumption ◽  
Medial Prefrontal Cortex ◽  
Neuronal Excitability ◽  
Cell Types ◽  
Brain Regions ◽  
Alcohol Preference ◽  
Hcn Channels ◽  
Direct Role ◽  
Genetic Deletion

The hyperpolarization-activated cyclic nucleotide-gated channel (HCN), which underlies the hyperpolarization-activated cation current (Ih), has diverse roles in regulating neuronal excitability across cell types and brain regions. Recently, HCN channels have been implicated in preclinical models of substance abuse including alcohol. In the prefrontal cortex of rodents, HCN expression and Ih magnitude are developmentally regulated during adolescence and may be vulnerable to alcohol’s effects. In mice, binge alcohol consumption during the adolescent period results in a sustained reduction in Ih that coincides with increased alcohol consumption in adulthood, yet the direct role HCN channels have on alcohol consumption are unknown. Here, we show that the genetic deletion of Hcn1 causes an increase in alcohol preference on intermittent 2-bottle choice task in homozygous null (HCN1−/−) male mice compared to wild-type littermates without affecting saccharine or quinine preference. The targeted viral deletion of HCN1 in pyramidal neurons of the medial prefrontal cortex resulted in a gradual loss of Hcn1 expression and a reduction in Ih magnitude during adolescence, however, this did not significantly affect alcohol consumption or preference. We conclude that while HCN1 regulates alcohol preference, the genetic deletion of Hcn1 in the medial prefrontal cortex does not appear to be the locus for this effect.

scholarly journals Biochemical abnormalities of the medial temporal lobe and medial prefrontal cortex in late-life depression

2009 ◽  
Vol 172 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Talaignair N. Venkatraman ◽  
Ranga R. Krishnan ◽  
David C. Steffens ◽  
Allen W. Song ◽  
Warren D. Taylor
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Late Life ◽  
Late Life Depression ◽  
Biochemical Abnormalities

scholarly journals Neural Pattern Change During Encoding of a Narrative Predicts Retrospective Duration Estimates

2016 ◽  
Author(s):  
Olga Lositsky ◽  
Janice Chen ◽  
Daniel Toker ◽  
Christopher J Honey ◽  
Jordan L Poppenk ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Entorhinal Cortex ◽  
Temporal Lobe ◽  
Medial Temporal Lobes ◽  
Anterior Temporal Lobe ◽  
Temporal Lobes ◽  
Contextual Features ◽  
Pattern Change ◽  
Behavioral Studies ◽  
The Right

What mechanisms support our ability to estimate durations on the order of minutes? Behavioral studies in humans have shown that changes in contextual features lead to overestimation of past durations. Based on evidence that the medial temporal lobes and prefrontal cortex represent contextual features, we related the degree of fMRI pattern change in these regions with people's subsequent duration estimates. After listening to a radio story in the scanner, participants were asked how much time had elapsed between pairs of clips from the story. Our ROI analysis found that the neural pattern distance between two clips at encoding was correlated with duration estimates in the right entorhinal cortex and right pars orbitalis. Moreover, a whole-brain searchlight analysis revealed a cluster spanning the right anterior temporal lobe. Our findings provide convergent support for the hypothesis that retrospective time judgments are driven by 'drift' in contextual representations supported by these regions.

scholarly journals Integrating memories: Congruency and reactivation aid memory integration through reinstatement of prior knowledge

2019 ◽  
Author(s):  
Marlieke T.R. van Kesteren ◽  
Paul Rignanese ◽  
Pierre G. Gianferrara ◽  
Lydia Krabbendam ◽  
Martijn Meeter
Keyword(s):  
Prefrontal Cortex ◽  
Prior Knowledge ◽  
Medial Prefrontal Cortex ◽  
Medial Temporal Lobe ◽  
Knowledge Building ◽  
Activity Patterns ◽  
Brain Regions ◽  
Memory Integration ◽  
The Brain ◽  
Parahippocampal Place Area

AbstractBuilding consistent knowledge schemas that organize information and guide future learning is of great importance in everyday life. Such knowledge building is suggested to occur through reinstatement of prior knowledge during new learning in stimulus-specific brain regions. This process is proposed to yield integration of new with old memories, supported by the medial prefrontal cortex (mPFC) and medial temporal lobe (MTL). Possibly as a consequence, congruency of new information with prior knowledge is known to enhance subsequent memory. Yet, it is unknown how reactivation and congruency interact to optimize memory integration processes that lead to knowledge schemas. To investigate this question, we here used an adapted AB-AC inference paradigm in combination with functional Magnetic Resonance Imaging (fMRI). Participants first studied an AB-association followed by an AC-association, so B (a scene) and C (an object) were indirectly linked through their common association with A (an unknown pseudoword). BC-associations were either congruent or incongruent with prior knowledge (e.g. a bathduck or a hammer in a bathroom), and participants were asked to report subjective reactivation strength for B while learning AC. Behaviorally, both the congruency and reactivation measures enhanced memory integration. In the brain, these behavioral effects related to univariate and multivariate parametric effects of congruency and reactivation on activity patterns in the MTL, mPFC, and Parahippocampal Place Area (PPA). Moreover, mPFC exhibited larger connectivity with the PPA for more congruent associations. These outcomes provide insights into the neural mechanisms underlying memory integration enhancement, which can be important for educational learning.Significance statementHow does our brain build knowledge through integrating information that is learned at different periods in time? This question is important in everyday learning situations such as educational settings. Using an inference paradigm, we here set out to investigate how congruency with, and active reactivation of previously learned information affects memory integration processes in the brain. Both these factors were found to relate to activity in memory-related regions such as the medial prefrontal cortex (mPFC) and the hippocampus. Moreover, activity in the parahippocampal place area (PPA), assumed to reflect reinstatement of the previously learned associate, was found to predict subjective reactivation strength. These results show how we can moderate memory integration processes to enhance subsequent knowledge building.

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