scholarly journals Hierarchical reasoning by neural circuits in the frontal cortex

Science ◽  
2019 ◽  
Vol 364 (6441) ◽  
pp. eaav8911 ◽  
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.

scholarly journals The geometry of abstraction in hippocampus and pre-frontal cortex

2018 ◽  
Author(s):  
Silvia Bernardi ◽  
Marcus K. Benna ◽  
Mattia Rigotti ◽  
Jérôme Munuera ◽  
Stefano Fusi ◽  
...  
Keyword(s):  
Frontal Cortex ◽  
Cognitive Flexibility ◽  
Anterior Cingulate ◽  
Stimulus Response ◽  
Hidden Variable ◽  
Neural Ensembles ◽  
Neural Representations ◽  
Cognitive Operations ◽  
Task Conditions ◽  
The Brain

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.

scholarly journals Brain mechanisms underlying neuropsychiatric symptoms in Alzheimer’s disease: a systematic review of symptom-general and –specific lesion patterns

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yaojing Chen ◽  
Mingxi Dang ◽  
Zhanjun Zhang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Neuropsychiatric Symptoms ◽  
Onset Time ◽  
Anterior Cingulate ◽  
Neural Basis ◽  
Preclinical Ad ◽  
Disease Stages ◽  
Mild Cognitive Impairment Stage

AbstractNeuropsychiatric symptoms (NPSs) are common in patients with Alzheimer’s disease (AD) and are associated with accelerated cognitive impairment and earlier deaths. This review aims to explore the neural pathogenesis of NPSs in AD and its association with the progression of AD. We first provide a literature overview on the onset times of NPSs. Different NPSs occur in different disease stages of AD, but most symptoms appear in the preclinical AD or mild cognitive impairment stage and develop progressively. Next, we describe symptom-general and -specific patterns of brain lesions. Generally, the anterior cingulate cortex is a commonly damaged region across all symptoms, and the prefrontal cortex, especially the orbitofrontal cortex, is also a critical region associated with most NPSs. In contrast, the anterior cingulate-subcortical circuit is specifically related to apathy in AD, the frontal-limbic circuit is related to depression, and the amygdala circuit is related to anxiety. Finally, we elucidate the associations between the NPSs and AD by combining the onset time with the neural basis of NPSs.

scholarly journals Neural Changes Underlying Rapid Fly Song Evolution

2017 ◽  
Author(s):  
Yun Ding ◽  
Joshua L. Lillvis ◽  
Jessica Cande ◽  
Gordon J. Berman ◽  
Benjamin J. Arthur ◽  
...  
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Experimental Approach ◽  
Neural Circuits ◽  
Neural Circuitry ◽  
Courtship Song ◽  
Neural Basis ◽  
Electrophysiological Properties ◽  
Song Types ◽  
Behavioural Diversity

AbstractThe neural basis for behavioural evolution is poorly understood. Functional comparisons of homologous neurons may reveal how neural circuitry contributes to behavioural evolution, but homologous neurons cannot be identified and manipulated in most taxa. Here, we compare the function of homologous courtship song neurons by exporting neurogenetic reagents that label identified neurons in Drosophila melanogaster to D. yakuba. We found a conserved role for a cluster of brain neurons that establish a persistent courtship state. In contrast, a descending neuron with conserved electrophysiological properties drives different song types in each species. Our results suggest that song evolved, in part, due to changes in the neural circuitry downstream of this descending neuron. This experimental approach can be generalized to other neural circuits and therefore provides an experimental framework for studying how the nervous system has evolved to generate behavioural diversity.

scholarly journals Altered fear processing in adolescents with a history of severe childhood maltreatment: an fMRI study

2018 ◽  
Vol 48 (7) ◽  
pp. 1092-1101 ◽  
Author(s):  
H. Hart ◽  
L. Lim ◽  
M. A. Mehta ◽  
A. Simmons ◽  
K. A. H. Mirza ◽  
...  
Keyword(s):  
Substance Abuse ◽  
Functional Connectivity ◽  
Childhood Maltreatment ◽  
Emotion Processing ◽  
Anterior Cingulate ◽  
Healthy Controls ◽  
Neural Basis ◽  
Fmri Study ◽  
History Of ◽  
Psychiatric Conditions

AbstractBackgroundChildren with a history of maltreatment suffer from altered emotion processing but the neural basis of this phenomenon is unknown. This pioneering functional magnetic resonance imaging (fMRI) study investigated the effects of severe childhood maltreatment on emotion processing while controlling for psychiatric conditions, medication and substance abuse.MethodTwenty medication-naive, substance abuse-free adolescents with a history of childhood abuse, 20 psychiatric control adolescents matched on psychiatric diagnoses but with no maltreatment and 27 healthy controls underwent a fMRI emotion discrimination task comprising fearful, angry, sad happy and neutral dynamic facial expressions.ResultsMaltreated participants responded faster to fearful expressions and demonstrated hyper-activation compared to healthy controls of classical fear-processing regions of ventromedial prefrontal cortex (vmPFC) and anterior cingulate cortex, which survived at a more lenient threshold relative to psychiatric controls. Functional connectivity analysis, furthermore, demonstrated reduced connectivity between left vmPFC and insula for fear in maltreated participants compared to both healthy and psychiatric controls.ConclusionsThe findings show that people who have experienced childhood maltreatment have enhanced fear perception, both at the behavioural and neurofunctional levels, associated with enhanced fear-related ventromedial fronto-cingulate activation and altered functional connectivity with associated limbic regions. Furthermore, the connectivity adaptations were specific to the maltreatment rather than to the developing psychiatric conditions, whilst the functional changes were only evident at trend level when compared to psychiatric controls, suggesting a continuum. The neurofunctional hypersensitivity of fear-processing networks may be due to childhood over-exposure to fear in people who have been abused.

Orbitofrontal cortex output pathways: cingulate cortex, basal ganglia, and dopamine

2019 ◽  
pp. 145-164
Author(s):  
Edmund T. Rolls
Keyword(s):  
Orbitofrontal Cortex ◽  
Instrumental Learning ◽  
Cingulate Cortex ◽  
Reward Processing ◽  
Dopamine Neurons ◽  
Anterior Cingulate ◽  
Stimulus Response ◽  
Related Information ◽  
Outcome Information ◽  
Reward Information

The medial orbitofrontal cortex projects reward-related information to the pregenual cingulate cortex, and the lateral orbitofrontal cortex projects punishment and non-reward information to the supracallosal anterior cingulate cortex. These projections provide the reward outcome information needed for action-outcome goal value dependent instrumental learning by the cingulate cortex. The orbitofrontal cortex also projects reward-related information to the striatum for stimulus-response habit learning. Via the striatal route, and further in part via the habenula, the orbitofrontal cortex provides information about rewards and non-rewards that reached the brainstem dopamine neurons, some of which respond to positive reward prediction error, and the serotonin (5HT) neurons. The orbitofrontal cortex is therefore perhaps the key brain region involved in reward processing in the brain. The orbitofrontal cortex also has projections that can influence autonomic function, in part via the insula.

scholarly journals Choosing to view morbid information involves reward circuitry

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Suzanne Oosterwijk ◽  
Lukas Snoek ◽  
Jurriaan Tekoppele ◽  
Lara H. Engelbert ◽  
H. Steven Scholte
Keyword(s):  
Neural Circuits ◽  
Inferior Frontal Gyrus ◽  
Brain Regions ◽  
Anterior Cingulate ◽  
Viewing Condition ◽  
Verbal Cues ◽  
Negative Image ◽  
Reward Circuitry ◽  
Starting Point ◽  
Passive Viewing

Abstract People often seek out stories, videos or images that detail death, violence or harm. Considering the ubiquity of this behavior, it is surprising that we know very little about the neural circuits involved in choosing negative information. Using fMRI, the present study shows that choosing intensely negative stimuli engages similar brain regions as those that support extrinsic incentives and “regular” curiosity. Participants made choices to view negative and positive images, based on negative (e.g., a soldier kicks a civilian against his head) and positive (e.g., children throw flower petals at a wedding) verbal cues. We hypothesized that the conflicting, but relatively informative act of choosing to view a negative image, resulted in stronger activation of reward circuitry as opposed to the relatively uncomplicated act of choosing to view a positive stimulus. Indeed, as preregistered, we found that choosing negative cues was associated with activation of the striatum, inferior frontal gyrus, anterior insula, and anterior cingulate cortex, both when contrasting against a passive viewing condition, and when contrasting against positive cues. These findings nuance models of decision-making, valuation and curiosity, and are an important starting point when considering the value of seeking out negative content.

scholarly journals Resting-State Isolated Effective Connectivity of the Cingulate Cortex as a Neurophysiological Biomarker in Patients with Severe Treatment-Resistant Schizophrenia

2020 ◽  
Vol 10 (3) ◽  
pp. 89
Author(s):  
Masataka Wada ◽  
Shinichiro Nakajima ◽  
Ryosuke Tarumi ◽  
Fumi Masuda ◽  
Takahiro Miyazaki ◽  
...  
Keyword(s):  
Resting State ◽  
Effective Connectivity ◽  
Treatment Resistance ◽  
Cingulate Cortex ◽  
Posterior Cingulate Cortex ◽  
Anterior Cingulate ◽  
Treatment Resistant ◽  
Neural Basis ◽  
Subject Factor ◽  
Post Hoc

Background: The neural basis of treatment-resistant schizophrenia (TRS) remains unclear. Previous neuroimaging studies suggest that aberrant connectivity between the anterior cingulate cortex (ACC) and default mode network (DMN) may play a key role in the pathophysiology of TRS. Thus, we aimed to examine the connectivity between the ACC and posterior cingulate cortex (PCC), a hub of the DMN, computing isolated effective coherence (iCoh), which represents causal effective connectivity. Methods: Resting-state electroencephalogram with 19 channels was acquired from seventeen patients with TRS and thirty patients with non-TRS (nTRS). The iCoh values between the PCC and ACC were calculated using sLORETA software. We conducted four-way analyses of variance (ANOVAs) for iCoh values with group as a between-subject factor and frequency, directionality, and laterality as within-subject factors and post-hoc independent t-tests. Results: The ANOVA and post-hoc t-tests for the iCoh ratio of directionality from PCC to ACC showed significant findings in delta (t45 = 7.659, p = 0.008) and theta (t45 = 8.066, p = 0.007) bands in the left side (TRS < nTRS). Conclusion: Left delta and theta PCC and ACC iCoh ratio may represent a neurophysiological basis of TRS. Given the preliminary nature of this study, these results warrant further study to confirm the importance of iCoh as a clinical indicator for treatment-resistance.

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