scholarly journals Contributions of different prefrontal cortical regions to abstract rule acquisition and reversal in monkeys

2017 ◽  
Author(s):  
Giancarlo La Camera ◽  
Sebastien Bouret ◽  
Barry J. Richmond
Keyword(s):  
Orbitofrontal Cortex ◽  
Brain Regions ◽  
Abstract Concept ◽  
Abstract Concepts ◽  
Prefrontal Cortical ◽  
Rule Acquisition ◽  
Learning Rules ◽  
Association Task ◽  
Abstract Rule ◽  
Cortical Regions

AbstractThe ability to learn and follow abstract rules relies on intact prefrontal regions including the lateral prefrontal cortex (LPFC) and the orbitofrontal cortex (OFC). Here, we investigate the specific roles of these brain regions in learning rules that depend critically on the formation of abstract concepts as opposed to simpler input-output associations. To this aim, we tested monkeys with bilateral removals of either LPFC or OFC on a rapidly learned task requiring the formation of the abstract concept of same vs. different. While monkeys with OFC removals were significantly slower than controls at both acquiring and reversing the concept-based rule, monkeys with LPFC removals were not impaired in acquiring the task, but were significantly slower at rule reversal. Neither group was impaired in the acquisition or reversal of a delayed visual cue-outcome association task without a concept-based rule. These results suggest that OFC is essential for the implementation of a concept-based rule, whereas LPFC seems essential for its modification once established.

scholarly journals Fronto-striatal atrophy correlates of neuropsychiatric dysfunction in frontotemporal dementia (FTD) and Alzheimer's disease (AD)

2013 ◽  
Vol 7 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Dong Seok Yi ◽  
Maxime Bertoux ◽  
Eneida Mioshi ◽  
John R. Hodges ◽  
Michael Hornberger
Keyword(s):  
Frontotemporal Dementia ◽  
Rating Scale ◽  
Brain Regions ◽  
Abnormal Behaviour ◽  
Behavioural Symptoms ◽  
Visual Rating ◽  
Prefrontal Cortical ◽  
Mri Scans ◽  
Visual Rating Scale ◽  
Cortical Regions

ABSTRACT Behavioural disturbances in frontotemporal dementia (FTD) are thought to reflect mainly atrophy of cortical regions. Recent studies suggest that subcortical brain regions, in particular the striatum, are also significantly affected and this pathology might play a role in the generation of behavioural symptoms. Objective: To investigate prefrontal cortical and striatal atrophy contributions to behavioural symptoms in FTD. Methods: One hundred and eighty-two participants (87 FTD patients, 39 AD patients and 56 controls) were included. Behavioural profiles were established using the Cambridge Behavioural Inventory Revised (CBI-R) and Frontal System Behaviour Scale (FrSBe). Atrophy in prefrontal (VMPFC, DLPFC) and striatal (caudate, putamen) regions was established via a 5-point visual rating scale of the MRI scans. Behavioural scores were correlated with atrophy rating scores. Results: Behavioural and atrophy ratings demonstrated that patients were significantly impaired compared to controls, with bvFTD being most severely affected. Behavioural-anatomical correlations revealed that VMPFC atrophy was closely related to abnormal behaviour and motivation disturbances. Stereotypical behaviours were associated with both VMPFC and striatal atrophy. By contrast, disturbance of eating was found to be related to striatal atrophy only. Conclusion: Frontal and striatal atrophy contributed to the behavioural disturbances seen in FTD, with some behaviours related to frontal, striatal or combined fronto-striatal pathology. Consideration of striatal contributions to the generation of behavioural disturbances should be taken into account when assessing patients with potential FTD.

scholarly journals Imaging recent to very remote object-in-place memories in the medial temporal lobe and prefrontal cortex

2020 ◽  
Author(s):  
Erika Atucha ◽  
Celia Fuerst ◽  
Magdalena Sauvage
Keyword(s):  
Memory Retrieval ◽  
Medial Temporal Lobe ◽  
Brain Regions ◽  
Remote Memory ◽  
General Mechanism ◽  
Cortical Areas ◽  
Prefrontal Cortical ◽  
Place Task ◽  
Cortical Regions ◽  
Over Time

Studies on patient H.M inspired many experiments on the role of the hippocampus and the neocortex in retrieving recent and remote memories. Cortical regions become increasingly engaged for memory retrieval over time, while conflicting results emerge regarding the engagement of the hippocampus, suggested to be ongoing by some or restricted to the retrieval of recent memories by others. In the study of Lux et al, 2016 we tested that this discrepancy might stem from failing to dissociate CA1 from CA3s contribution to memory retrieval over time as CA3 is known to support computations more sensitive to time than CA1. We also reported that parahippocampal cortical areas with tied anatomical connections with the hippocampus were increasingly engaged over time (Lux et al., elife , 2016). This study used a fear conditioning paradigm as emotionally arousing experiences are better remembered than memories devoid of fear content. Here we address whether the differential contribution of brain regions is a general mechanism also subserving memory retrieval devoid of fear content. We succeeded in developing an object-in-place task to investigate remote memory retrieval up to 6 months and the contribution of CA1, CA3, parahippocampal and prefrontal cortical areas to the retrieval of recent versus very remote memories using a high resolution molecular imaging technique based on the detection of the IEG RNA Arc. Preliminary results show that the disengagement of CA3 and persistent engagement of CA1 seem to be a general mechanism in supporting retrieval of remote memory for events.

scholarly journals Situational systematicity: A role for schema in understanding the differences between abstract and concrete concepts

2019 ◽  
Author(s):  
Charles P. Davis ◽  
Gerry Altmann ◽  
Eiling Yee
Keyword(s):  
Concept Learning ◽  
Brain Regions ◽  
Control Network ◽  
Abstract Concept ◽  
Abstract Concepts ◽  
Critical Determinant ◽  
Per Se ◽  
Concrete Concepts ◽  
Insight Into ◽  
Concrete Concept

Abstract concepts differ from concrete concepts in a number of ways. Here, we focus on what we refer to as situational systematicity: The objects and relations that constitute an abstract concept (e.g., justice) are more dispersed through space and time than are the objects and relations that typically constitute a concrete concept (e.g., chair); a larger set of objects and relations might potentially constitute an abstract concept than a concrete one; and exactly which objects and relations constitute a concept is likely more context-dependent for abstract than for concrete concepts. We thus refer to abstract concepts as having low situational systematicity. We contend that situational systematicity, rather than abstractness per se, may be a critical determinant of the cognitive, behavioral, and neural phenomena typically associated with concepts. We also contend that investigating concepts through the lens of schema provides insight into the situation-based dynamics of concept learning and representation, and into the functional significance of the interactions between brain regions that make up the schema control network.

scholarly journals Dynamic shifts of visual and saccadic signals in prefrontal cortical regions 8Ar and FEF

2019 ◽  
Author(s):  
Sanjeev B. Khanna ◽  
Jonathan A. Scott ◽  
Matthew A. Smith
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Spatial Working Memory ◽  
Active Vision ◽  
Brain Regions ◽  
Motor Tasks ◽  
Prefrontal Cortical ◽  
Spatial Registration ◽  
Cortical Regions ◽  
Spatial Locations

AbstractActive vision is a fundamental process by which primates gather information about the external world. Multiple brain regions have been studied in the context of simple active vision tasks in which a visual target’s appearance is temporally separated from saccade execution. Most neurons have tight spatial registration between visual and saccadic signals, and in areas such as prefrontal cortex (PFC) some neurons show persistent delay activity that links visual and motor epochs and has been proposed as a basis for spatial working memory. Many PFC neurons also show rich dynamics, which have been attributed to alternative working memory codes and the representation of other task variables. Our study investigated the transition between processing a visual stimulus and generating an eye movement in populations of PFC neurons in macaque monkeys performing a memory guided saccade task. We found that neurons in two subregions of PFC, the frontal eye fields (FEF) and area 8Ar, differed in their dynamics and spatial response profiles. These dynamics could be attributed largely to shifts in the spatial profile of visual and motor responses in individual neurons. This led to visual and motor codes for particular spatial locations that were instantiated by different mixtures of neurons, which could be important in PFC’s flexible role in multiple sensory, cognitive, and motor tasks.New and NoteworthyA central question in neuroscience is how the brain transitions from sensory representations to motor outputs. The prefrontal cortex contains neurons that have long been implicated as important in this transition and in working memory. We found evidence for rich and diverse tuning in these neurons, that was often spatially misaligned between visual and saccadic responses. This feature may play an important role in flexible working memory capabilities.

scholarly journals Brain Anatomical Covariation Patterns Linked to Binge Drinking and Age at First Full Drink Prior to 21 Years

2020 ◽  
Author(s):  
Yihong Zhao ◽  
R. Todd Constable ◽  
Denise Hien ◽  
Tammy Chung ◽  
Marc N. Potenza
Keyword(s):  
Binge Drinking ◽  
Surface Area ◽  
Brain Regions ◽  
Structural Pattern ◽  
Independent Dataset ◽  
Prefrontal Cortical ◽  
Human Connectome Project ◽  
Mixed Regression ◽  
Cortical Regions ◽  
The Individual

ABSTRACTBinge drinking and age at first full drink of alcohol prior to 21 years (AFD<21) have been linked to neuroanatomical differences in cortical and subcortical grey matter (GM) volume, cortical thickness, and surface area. Despite the potential to reveal novel network-level relationships, structural covariation patterns among these morphological measures have yet to be examined relative to binge drinking and AFD<21. Here, we used the Joint and Individual Variance Explained (JIVE) method to characterize structural covariation patterns common across and specific to morphological measures in 293 participants (149 individuals with binge drinking and 144 healthy controls) from the Human Connectome Project (HCP). An independent dataset (Nathan Kline Institute Rockland Sample; NKI-RS) was used to examine reproducibility/ generalizability. We identified a highly reproducible joint component dominated by structural covariation between GM volume in the brainstem and thalamus proper, and GM volume and surface area in prefrontal cortical regions. Using linear mixed regression models, we found that this joint component was related to AFD<21 in both the HCP and NKI-RS datasets, whereas the individual thickness component associated with binge drinking and AFD<21 in the HCP dataset was not statistically significant in the NKI-RS sample. Taken together, our results show that a highly reproducible structural pattern involving covariation in brain regions relevant to thalamic-PFC-brainstem neural circuitry is linked to age at first full drink.

Growth of prefrontal and limbic brain regions and anxiety disorders in children born very preterm

2021 ◽  
pp. 1-12
Author(s):  
Courtney P. Gilchrist ◽  
Deanne K. Thompson ◽  
Bonnie Alexander ◽  
Claire E. Kelly ◽  
Karli Treyvaud ◽  
...  
Keyword(s):  
Anxiety Disorder ◽  
Anxiety Disorders ◽  
Orbitofrontal Cortex ◽  
Developmental Trajectories ◽  
Brain Regions ◽  
Social Risk ◽  
Intracranial Volume ◽  
Total Brain Volume ◽  
Very Preterm ◽  
The Right

Abstract Background Children born very preterm (VP) display altered growth in corticolimbic structures compared with full-term peers. Given the association between the cortiocolimbic system and anxiety, this study aimed to compare developmental trajectories of corticolimbic regions in VP children with and without anxiety diagnosis at 13 years. Methods MRI data from 124 VP children were used to calculate whole brain and corticolimbic region volumes at term-equivalent age (TEA), 7 and 13 years. The presence of an anxiety disorder was assessed at 13 years using a structured clinical interview. Results VP children who met criteria for an anxiety disorder at 13 years (n = 16) displayed altered trajectories for intracranial volume (ICV, p < 0.0001), total brain volume (TBV, p = 0.029), the right amygdala (p = 0.0009) and left hippocampus (p = 0.029) compared with VP children without anxiety (n = 108), with trends in the right hippocampus (p = 0.062) and left medial orbitofrontal cortex (p = 0.079). Altered trajectories predominantly reflected slower growth in early childhood (0–7 years) for ICV (β = −0.461, p = 0.020), TBV (β = −0.503, p = 0.021), left (β = −0.518, p = 0.020) and right hippocampi (β = −0.469, p = 0.020) and left medial orbitofrontal cortex (β = −0.761, p = 0.020) and did not persist after adjusting for TBV and social risk. Conclusions Region- and time-specific alterations in the development of the corticolimbic system in children born VP may help to explain an increase in anxiety disorders observed in this population.

scholarly journals Cochlear activity in silent cue-target intervals shows a theta-rhythmic pattern and is correlated to attentional alpha and theta modulations

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Moritz Herbert Albrecht Köhler ◽  
Gianpaolo Demarchi ◽  
Nathan Weisz
Keyword(s):  
Selective Attention ◽  
Brain Regions ◽  
Attentional Focus ◽  
Theta Activity ◽  
Superior Olivary Complex ◽  
Rhythmic Pattern ◽  
Auditory Input ◽  
Auditory Selective Attention ◽  
Beta Power ◽  
Cortical Regions

AbstractBackgroundA long-standing debate concerns where in the processing hierarchy of the central nervous system (CNS) selective attention takes effect. In the auditory system, cochlear processes can be influenced via direct and mediated (by the inferior colliculus) projections from the auditory cortex to the superior olivary complex (SOC). Studies illustrating attentional modulations of cochlear responses have so far been limited to sound-evoked responses. The aim of the present study is to investigate intermodal (audiovisual) selective attention in humans simultaneously at the cortical and cochlear level during a stimulus-free cue-target interval.ResultsWe found that cochlear activity in the silent cue-target intervals was modulated by a theta-rhythmic pattern (~ 6 Hz). While this pattern was present independently of attentional focus, cochlear theta activity was clearly enhanced when attending to the upcoming auditory input. On a cortical level, classical posterior alpha and beta power enhancements were found during auditory selective attention. Interestingly, participants with a stronger release of inhibition in auditory brain regions show a stronger attentional modulation of cochlear theta activity.ConclusionsThese results hint at a putative theta-rhythmic sampling of auditory input at the cochlear level. Furthermore, our results point to an interindividual variable engagement of efferent pathways in an attentional context that are linked to processes within and beyond processes in auditory cortical regions.

scholarly journals The Role of Primate Prefrontal Cortex in Bias and Shift Between Visual Dimensions

2019 ◽  
Vol 30 (1) ◽  
pp. 85-99 ◽  
Author(s):  
Farshad A Mansouri ◽  
Mark J Buckley ◽  
Daniel J Fehring ◽  
Keiji Tanaka
Keyword(s):  
Prefrontal Cortex ◽  
Anterior Cingulate ◽  
Top Down ◽  
Attentional Processes ◽  
Prefrontal Cortical ◽  
Frontopolar Cortex ◽  
Dorsolateral Prefrontal ◽  
Cortical Regions ◽  
Visual Cortical ◽  
Bilateral Lesions

Abstract Imaging and neural activity recording studies have shown activation in the primate prefrontal cortex when shifting attention between visual dimensions is necessary to achieve goals. A fundamental unanswered question is whether representations of these dimensions emerge from top-down attentional processes mediated by prefrontal regions or from bottom-up processes within visual cortical regions. We hypothesized a causative link between prefrontal cortical regions and dimension-based behavior. In large cohorts of humans and macaque monkeys, performing the same attention shifting task, we found that both species successfully shifted between visual dimensions, but both species also showed a significant behavioral advantage/bias to a particular dimension; however, these biases were in opposite directions in humans (bias to color) versus monkeys (bias to shape). Monkeys’ bias remained after selective bilateral lesions within the anterior cingulate cortex (ACC), frontopolar cortex, dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), or superior, lateral prefrontal cortex. However, lesions within certain regions (ACC, DLPFC, or OFC) impaired monkeys’ ability to shift between these dimensions. We conclude that goal-directed processing of a particular dimension for the executive control of behavior depends on the integrity of prefrontal cortex; however, representation of competing dimensions and bias toward them does not depend on top-down prefrontal-mediated processes.

scholarly journals Functional Neuroanatomy of Contextual Acquisition of Concrete and Abstract Words

2009 ◽  
Vol 21 (11) ◽  
pp. 2154-2171 ◽  
Author(s):  
Anna Mestres-Missé ◽  
Thomas F. Münte ◽  
Antoni Rodriguez-Fornells
Keyword(s):  
Native Speakers ◽  
Brain Regions ◽  
Functional Neuroanatomy ◽  
Linguistic Context ◽  
Abstract Concepts ◽  
New Words ◽  
Simulation Paradigm ◽  
Abstract Words ◽  
The Brain ◽  
Concrete Words

The meaning of a novel word can be acquired by extracting it from linguistic context. Here we simulated word learning of new words associated to concrete and abstract concepts in a variant of the human simulation paradigm that provided linguistic context information in order to characterize the brain systems involved. Native speakers of Spanish read pairs of sentences in order to derive the meaning of a new word that appeared in the terminal position of the sentences. fMRI revealed that learning the meaning associated to concrete and abstract new words was qualitatively different and recruited similar brain regions as the processing of real concrete and abstract words. In particular, learning of new concrete words selectively boosted the activation of the ventral anterior fusiform gyrus, a region driven by imageability, which has previously been implicated in the processing of concrete words.

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