scholarly journals Multiple spatial codes for navigating 2-D semantic spaces

2020 ◽  
Author(s):  
Simone Viganò ◽  
Valerio Rubino ◽  
Antonio Di Soccio ◽  
Marco Buiatti ◽  
Manuela Piazza
Keyword(s):  
Physical Space ◽  
Semantic Space ◽  
Brain Regions ◽  
Head Direction ◽  
Word Meanings ◽  
Neuronal Coding ◽  
Coding Schemes ◽  
Direction Of Movement ◽  
Human Participants ◽  
The Right

SummaryWhen mammals navigate in the physical environment, specific neurons such as grid-cells, head-direction cells, and place-cells activate to represent the navigable surface, the faced direction of movement, and the specific location the animal is visiting. Here we test the hypothesis that these codes are also activated when humans navigate abstract language-based representational spaces. Human participants learnt the meaning of novel words as arbitrary signs referring to specific artificial audiovisual objects varying in size and sound. Next, they were presented with sequences of words and asked to process them semantically while we recorded the activity of their brain using fMRI. Processing words in sequence was conceivable as movements in the semantic space, thus enabling us to systematically search for the different types of neuronal coding schemes known to represent space during navigation. By applying a combination of representational similarity and fMRI-adaptation analyses, we found evidence of i) a grid-like code in the right postero-medial entorhinal cortex, representing the general bidimensional layout of the novel semantic space; ii) a head-direction-like code in parietal cortex and striatum, representing the faced direction of movements between concepts; and iii) a place-like code in medial prefrontal, orbitofrontal, and mid cingulate cortices, representing the Euclidean distance between concepts. We also found evidence that the brain represents 1-dimensional distances between word meanings along individual sensory dimensions: implied size was encoded in secondary visual areas, and implied sound in Heschl’s gyrus/Insula. These results reveal that mentally navigating between 2D word meanings is supported by a network of brain regions hosting a variety of spatial codes, partially overlapping with those recruited for navigation in physical space.

scholarly journals Global and Local Head Direction Coding in the Human Brain

2021 ◽  
Author(s):  
J. P. Shine ◽  
T. Wolbers
Keyword(s):  
Reference Frames ◽  
Brain Regions ◽  
Retrosplenial Cortex ◽  
Specific Reference ◽  
Head Direction ◽  
Imaging Data ◽  
Neural Basis ◽  
Local Environments ◽  
Human Participants ◽  
Global And Local

AbstractOrientation-specific head direction (HD) cells increase their firing rate to indicate one’s facing direction in the environment. Rodent studies suggest HD cells in distinct areas of thalamus and retrosplenial cortex (RSC) code either for global (relative to the wider environment) or local (e.g., room-specific) reference frames. To investigate whether similar neuroanatomical dissociations exist in humans, we reanalysed functional magnetic resonance imaging data in which participants learned the orientation of unique images in separate local environments relative to distinct global landmarks (Shine, Valdés-Herrera, Hegarty, & Wolbers, 2016). The environment layout meant that we could establish two separate multivariate analysis models in which the HD on individual trials was coded relative either to global (North, South, East, West) or local (Front, Back, Right, Left) reference frames. Examining the data first in key regions of interest (ROI) for HD coding, we replicated our previous results and found that global HD was decodable in the thalamus and precuneus; the RSC, however, was sensitive only to local HD. Extending recent findings in both humans and rodents, V1 was sensitive to both HD reference frames. Additional small volume-corrected searchlight analyses supported the ROI results and indicated that the anatomical locus of the thalamic global HD coding was located in the medial thalamus, bordering the anterior thalamus, a region critical for global HD coding in rodents. Our findings elucidate further the putative neural basis of HD coding in humans, and suggest that distinct brain regions code for different frames of reference in HD.Significance statementHead direction (HD) cells provide a neural signal as to one’s orientation in the environment. HD can be coded relative to global or local (e.g., room-specific) reference frames, with studies suggesting that distinct areas of thalamus and retrosplenial cortex (RSC) code for this information. We reanalysed fMRI data where human participants associated images with global HDs before undergoing scanning. The design enabled us to examine both global and local HD coding. Supporting previous findings, global HD was decodable in thalamus, however the RSC coded only for local HD. We found evidence also for both reference frames in V1. These findings elucidate the putative neural basis of HD coding in humans, with distinct brain regions coding for different HD reference frames.

scholarly journals Anticipatory neural activity improves the decoding accuracy for dynamic head-direction signals

2018 ◽  
Author(s):  
Johannes Zirkelbach ◽  
Martin Stemmler ◽  
Andreas V.M. Herz
Keyword(s):  
Time Window ◽  
Brain Regions ◽  
Network Size ◽  
Network Activity ◽  
Head Direction ◽  
Functional Interpretation ◽  
Preferred Direction ◽  
Dynamic Head ◽  
Long Read ◽  
The Right

AbstractInsects and vertebrates harbor specific neurons that encode the animal’s head direction (HD) and provide an internal compass for spatial navigation. Each HD cell fires most strongly in one preferred direction. As the animal turns its head, however, HD cells in rat anterodorsal thalamic nucleus (ADN) and other brain areas fire already before their preferred direction is reached, as if the neurons anticipated the future head direction. This phenomenon has been explained at a mechanistic level but a functional interpretation is still missing. To close this gap, we use a computational approach based on the animal’s movement statistics and a simple model for the behavior of the ADN head-direction network. Network activity is read out using population vectors in a biologically plausible manner, so that only past spikes are taken into account. We find that anticipatory firing improves the representation of the present HD by reducing the motion-induced temporal bias inherent in causal decoding. The amount of anticipation observed in ADN enhances the precision of the HD compass read-out by up to 40%. In addition, our framework predicts that neural integration times not only reflect biophysical constraints, but also the statistics of natural stimuli; anticipatory tuning should be found whenever neurons encode sensory signals that change gradually in time.Significance statementAcross different brain regions, populations of noisy neurons encode dynamically changing stimuli. Decoding a time-varying stimulus from the population response involves a trade-off: For short read-out times, stimulus estimates are unreliable as the number of stochastic spikes will be small; for long read-out times, estimates are biased because they lag behind the true stimulus. We show that optimal decoding relies not only on finding the right read-out time window, but requires neurons to anticipate future stimulus values. We apply this framework to the rodent head-direction system and show that the experimentally observed anticipation of future head directions can be explained at a quantitative level from the neuronal tuning properties, the network size, and the animal’s head-movement statistics.

Neural Underpinnings of Numerical and Spatial Cognition: An fMRI Meta-Analysis of Brain Regions Associated with Symbolic Number, Arithmetic, and Mental Rotation

2019 ◽  
Author(s):  
Zachary Hawes ◽  
H Moriah Sokolowski ◽  
Chuka Bosah Ononye ◽  
Daniel Ansari
Keyword(s):  
Mental Rotation ◽  
Parietal Lobe ◽  
Meta Analysis ◽  
Likelihood Estimation ◽  
Brain Regions ◽  
Angular Gyrus ◽  
Number Representation ◽  
Neural Underpinnings ◽  
The Right ◽  
Symbolic Number

Where and under what conditions do spatial and numerical skills converge and diverge in the brain? To address this question, we conducted a meta-analysis of brain regions associated with basic symbolic number processing, arithmetic, and mental rotation. We used Activation Likelihood Estimation (ALE) to construct quantitative meta-analytic maps synthesizing results from 86 neuroimaging papers (~ 30 studies/cognitive process). All three cognitive processes were found to activate bilateral parietal regions in and around the intraparietal sulcus (IPS); a finding consistent with shared processing accounts. Numerical and arithmetic processing were associated with overlap in the left angular gyrus, whereas mental rotation and arithmetic both showed activity in the middle frontal gyri. These patterns suggest regions of cortex potentially more specialized for symbolic number representation and domain-general mental manipulation, respectively. Additionally, arithmetic was associated with unique activity throughout the fronto-parietal network and mental rotation was associated with unique activity in the right superior parietal lobe. Overall, these results provide new insights into the intersection of numerical and spatial thought in the human brain.

CYBERCHONDRIA INFORMATION CLINIC: Internet's Impact on your Health (Preprint)

2019 ◽  
Author(s):  
Valentina Escotet Espinoza
Keyword(s):  
Human Life ◽  
Brain Regions ◽  
Physical Symptoms ◽  
Digital Design ◽  
Somatization Disorder ◽  
The Internet ◽  
Cultural Aspects ◽  
Starting Point ◽  
The Right ◽  
The Relationship

UNSTRUCTURED Over half of Americans report looking up health-related questions on the internet, including questions regarding their own ailments. The internet, in its vastness of information, provides a platform for patients to understand how to seek help and understand their condition. In most cases, this search for knowledge serves as a starting point to gather evidence that leads to a doctor’s appointment. However, in some cases, the person looking for information ends up tangled in an information web that perpetuates anxiety and further searches, without leading to a doctor’s appointment. The Internet can provide helpful and useful information; however, it can also be a tool for self-misdiagnosis. Said person craves the instant gratification the Internet provides when ‘googling’ – something one does not receive when having to wait for a doctor’s appointment or test results. Nevertheless, the Internet gives that instant response we demand in those moments of desperation. Cyberchondria, a term that has entered the medical lexicon in the 21st century after the advent of the internet, refers to the unfounded escalation of people’s concerns about their symptomatology based on search results and literature online. ‘Cyberchondriacs’ experience mistrust of medical experts, compulsion, reassurance seeking, and excessiveness. Their excessive online research about health can also be associated with unnecessary medical expenses, which primarily arise from anxiety, increased psychological distress, and worry. This vicious cycle of searching information and trying to explain current ailments derives into a quest for associating symptoms to diseases and further experiencing the other symptoms of said disease. This psychiatric disorder, known as somatization, was first introduced to the DSM-III in the 1980s. Somatization is a psycho-biological disorder where physical symptoms occur without any palpable organic cause. It is a disorder that has been renamed, discounted, and misdiagnosed from the beginning of the DSMs. Somatization triggers span many mental, emotional, and cultural aspects of human life. Our environment and social experiences can lay the blueprint for disorders to develop over time; an idea that is widely accepted for underlying psychiatric disorders such as depression and anxiety. The research is going in the right direction by exploring brain regions but needs to be expanded on from a sociocultural perspective. In this work, we explore the relationship between somatization disorder and the condition known as cyberchondria. First, we provide a background on each of the disorders, including their history and psychological perspective. Second, we proceed to explain the relationship between the two disorders, followed by a discussion on how this relationship has been studied in the scientific literature. Thirdly, we explain the problem that the relationship between these two disorders creates in society. Lastly, we propose a set of intervention aids and helpful resource prototypes that aim at resolving the problem. The proposed solutions ranged from a site-specific clinic teaching about cyberchondria to a digital design-coded chrome extension available to the public.

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 Functional network topology of the right insula affects emotion dysregulation in hyperactive-impulsive attention-deficit/hyperactivity disorder

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tammo Viering ◽  
Pieter J. Hoekstra ◽  
Alexandra Philipsen ◽  
Jilly Naaijen ◽  
Andrea Dietrich ◽  
...  
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Network Topology ◽  
Resting State ◽  
Latent Variable ◽  
Emotion Dysregulation ◽  
Adult Adhd ◽  
Brain Regions ◽  
Graph Analysis ◽  
Hyperactivity Disorder ◽  
The Right

AbstractEmotion dysregulation is common in attention-deficit/hyperactivity disorder (ADHD). It is highly prevalent in young adult ADHD and related to reduced well-being and social impairments. Neuroimaging studies reported neural activity changes in ADHD in brain regions associated with emotion processing and regulation. It is however unknown whether deficits in emotion regulation relate to changes in functional brain network topology in these regions. We used a combination of graph analysis and structural equation modelling (SEM) to analyze resting-state functional connectivity in 147 well-characterized young adults with ADHD and age-matched healthy controls from the NeuroIMAGE database. Emotion dysregulation was gauged with four scales obtained from questionnaires and operationalized through a latent variable derived from SEM. Graph analysis was applied to resting-state data and network topology measures were entered into SEM models to identify brain regions whose local network integration and connectedness differed between subjects and was associated with emotion dysregulation. The latent variable of emotion dysregulation was characterized by scales gauging emotional distress, emotional symptoms, conduct symptoms, and emotional lability. In individuals with ADHD characterized by prominent hyperactivity-impulsivity, the latent emotion dysregulation variable was related to an increased clustering and local efficiency of the right insula. Thus, in the presence of hyperactivity-impulsivity, clustered network formation of the right insula may underpin emotion dysregulation in young adult ADHD.

scholarly journals A Connectome-Wide Functional Signature of Trait Anger

2021 ◽  
pp. 216770262110302
Author(s):  
M. Justin Kim ◽  
Maxwell L. Elliott ◽  
Annchen R. Knodt ◽  
Ahmad R. Hariri
Keyword(s):  
Functional Connectivity ◽  
Visual Information ◽  
Past Research ◽  
Brain Regions ◽  
Small Sample ◽  
Trait Anger ◽  
Frontal Pole ◽  
Brain Correlates ◽  
Small Sample Sizes ◽  
The Right

Past research on the brain correlates of trait anger has been limited by small sample sizes, a focus on relatively few regions of interest, and poor test–retest reliability of functional brain measures. To address these limitations, we conducted a data-driven analysis of variability in connectome-wide functional connectivity in a sample of 1,048 young adult volunteers. Multidimensional matrix regression analysis showed that self-reported trait anger maps onto variability in the whole-brain functional connectivity patterns of three brain regions that serve action-related functions: bilateral supplementary motor areas and the right lateral frontal pole. We then demonstrate that trait anger modulates the functional connectivity of these regions with canonical brain networks supporting somatomotor, affective, self-referential, and visual information processes. Our findings offer novel neuroimaging evidence for interpreting trait anger as a greater propensity to provoked action, which supports ongoing efforts to understand its utility as a potential transdiagnostic marker for disordered states characterized by aggressive behavior.

The Cortical Organization of Writing Sequence: Evidence From Observing Chinese Characters in Motion

2021 ◽  
Author(s):  
Zhaoqi Zhang ◽  
Qiming Yuan ◽  
Zeping Liu ◽  
Man Zhang ◽  
Junjie Wu ◽  
...  
Keyword(s):  
Structural Equation ◽  
Chinese Character ◽  
Inferior Frontal Gyrus ◽  
Hierarchical Control ◽  
Brain Regions ◽  
Brain Network ◽  
Equation Model ◽  
Chinese Characters ◽  
General Motor ◽  
The Right

Abstract Writing sequences play an important role in handwriting of Chinese characters. However, little is known regarding the integral brain patterns and network mechanisms of processing Chinese character writing sequences. The present study decoded brain patterns during observing Chinese characters in motion by using multi-voxel pattern analysis (MVPA), meta-analytic decoding analysis, and extended unified structural equation model (euSEM). We found that perception of Chinese character writing sequence recruited brain regions not only for general motor schema processing, i.e., the right inferior frontal gyrus, shifting and inhibition functions, i.e., the right postcentral gyrus and bilateral pre-SMA/dACC, but also for sensorimotor functions specific for writing sequences. More importantly, these brain regions formed a cooperatively top-down brain network where information was transmitted from brain regions for general motor schema processing to those specific for writing sequences. These findings not only shed light on the neural mechanisms of Chinese character writing sequences, but also extend the hierarchical control model on motor schema processing.

Early Microstructure Changes of White Matter Fiber Bundles in Patients with Amnestic Mild Cognitive Impairment Predicts Progression of Mild Cognitive Impairment to Alzheimer’s Disease

2021 ◽  
pp. 1-14
Author(s):  
Fangmei He ◽  
Yuchen Zhang ◽  
Xiaofeng Wu ◽  
Youjun Li ◽  
Jie Zhao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Brain Regions ◽  
Amnestic Mild Cognitive Impairment ◽  
Microstructure Changes ◽  
Disease Trajectory ◽  
Development Trajectory ◽  
The Right

Background: Amnestic mild cognitive impairment (aMCI) is the transitional stage between normal aging and Alzheimer’s disease (AD). Some aMCI patients will progress into AD eventually, whereas others will not. If the trajectory of aMCI can be predicted, it would enable early diagnosis and early therapy of AD. Objective: To explore the development trajectory of aMCI patients, we used diffusion tensor imaging to analyze the white matter microstructure changes of patients with different trajectories of aMCI. Methods: We included three groups of subjects:1) aMCI patients who convert to AD (MCI-P); 2) aMCI patients who remain in MCI status (MCI-S); 3) normal controls (NC). We analyzed the fractional anisotropy and mean diffusion rate of brain regions, and we adopted logistic binomial regression model to predicate the development trajectory of aMCI. Results: The fraction anisotropy value is significantly reduced, the mean diffusivity value is significantly increased in the two aMCI patient groups, and the MCI-P patients presented greater changes. Significant changes are mainly located in the cingulum, fornix, hippocampus, and uncinate fasciculus. These changed brain regions significantly correlated with the patient’s Mini-Mental State Examination scores. Conclusion: The study predicted the disease trajectory of different types of aMCI patients based on the characteristic values of the above-mentioned brain regions. The prediction accuracy rate can reach 90.2%, and the microstructure characteristics of the right cingulate band and the right hippocampus may have potential clinical application value to predict the disease trajectory.

Refining the Effects Observed in a Developmental Neurobehavioral Study of Ammonium Perchlorate Administered Orally in Drinking Water to Rats. II. Behavioral and Neurodevelopment Effects

2005 ◽  
Vol 24 (6) ◽  
pp. 451-467 ◽  
Author(s):  
Raymond G. York ◽  
John Barnett ◽  
Michael F. Girard ◽  
David R. Mattie ◽  
Marni V. K. Bekkedal ◽  
...  
Keyword(s):  
Drinking Water ◽  
Ammonium Perchlorate ◽  
Brain Regions ◽  
Male Rats ◽  
Male Rat ◽  
Sprague Dawley ◽  
Continuous Access ◽  
Brain Morphometry ◽  
The Central Nervous System ◽  
The Right

A developmental neurotoxicity study was conducted to generate additional data on the potential functional and morphological hazard to the central nervous system caused by ammonium perchlorate in offspring from in utero and lactation exposure. Female Sprague-Dawley rats (23 to 25/group) were given continuous access to 0 (carrier), 0.1, 1.0, 3.0, and 10.0 mg/kg-day perchlorate in the drinking water beginning 2 weeks prior to mating and continuing through day 10 of lactation for the behavioral function assessment or given continuous access to 0 (carrier), 0.1, 1.0, 3.0, and 30.0 mg/kg-day beginning on gestation day 0 and continuing through day 10 of lactation for neurodevelopment assessments. Motor activity was conducted on postpartum days 14, 18, and 22 and juvenile brain weights, neurohistopathological examinations, and regional brain morphometry were conducted on postpartum days 10 and 22. This research revealed a sexually dimorphic response, with some brain regions being larger in perchlorate-treated male rats than in comparable controls. Even so, there was no evidence of any obvious exposure-related effects on male rat brain weights or neuropathology. The most consistent exposure-related effect in the male pups was on the thickness of the corpus callosum, with both the right- and left-sided measures of the thickness of this white matter tract being significantly greater for the male pups in the 0.1 and 1.0 mg/kg-day exposure groups. The behavioral testing suggests prenatal exposure to ammonium perchlorate does not affect the development of gross motor movements in the pups.

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