scholarly journals Neuronal pattern separation of motion-relevant input in LIP activity

2017 ◽  
Vol 117 (2) ◽  
pp. 738-755 ◽  
Author(s):  
Nareg Berberian ◽  
Amanda MacPherson ◽  
Eloïse Giraud ◽  
Lydia Richardson ◽  
J.-P. Thivierge
Keyword(s):  
Neuronal Activity ◽  
Neural Activity ◽  
Population Model ◽  
Visual Motion ◽  
Temporal Dynamics ◽  
Strong Predictor ◽  
Pattern Separation ◽  
Sensory Stimuli ◽  
Sensory Discrimination

In various regions of the brain, neurons discriminate sensory stimuli by decreasing the similarity between ambiguous input patterns. Here, we examine whether this process of pattern separation may drive the rapid discrimination of visual motion stimuli in the lateral intraparietal area (LIP). Starting with a simple mean-rate population model that captures neuronal activity in LIP, we show that overlapping input patterns can be reformatted dynamically to give rise to separated patterns of neuronal activity. The population model predicts that a key ingredient of pattern separation is the presence of heterogeneity in the response of individual units. Furthermore, the model proposes that pattern separation relies on heterogeneity in the temporal dynamics of neural activity and not merely in the mean firing rates of individual neurons over time. We confirm these predictions in recordings of macaque LIP neurons and show that the accuracy of pattern separation is a strong predictor of behavioral performance. Overall, results propose that LIP relies on neuronal pattern separation to facilitate decision-relevant discrimination of sensory stimuli. NEW & NOTEWORTHY A new hypothesis is proposed on the role of the lateral intraparietal (LIP) region of cortex during rapid decision making. This hypothesis suggests that LIP alters the representation of ambiguous inputs to reduce their overlap, thus improving sensory discrimination. A combination of computational modeling, theoretical analysis, and electrophysiological data shows that the pattern separation hypothesis links neural activity to behavior and offers novel predictions on the role of LIP during sensory discrimination.

scholarly journals Bad Timing for Epileptic Networks: Role of Temporal Dynamics in Seizures and Cognitive Deficits

2021 ◽  
pp. 153575972110018
Author(s):  
Pierre-Pascal Lenck-Santini
Keyword(s):  
Neuronal Activity ◽  
Cognitive Deficits ◽  
Brain Function ◽  
Temporal Dynamics ◽  
Cognitive Outcomes ◽  
Present Evidence ◽  
Dynamic Coordination ◽  
Epileptic Networks

The precise coordination of neuronal activity is critical for optimal brain function. When such coordination fails, this can lead to dire consequences. In this review, I will present evidence that in epilepsy, failed coordination leads not only to seizures but also to alterations of the rhythmical patterns observed in the electroencephalogram and cognitive deficits. Restoring the dynamic coordination of epileptic networks could therefore both improve seizures and cognitive outcomes.

scholarly journals The Hemo-Neural Hypothesis: On The Role of Blood Flow in Information Processing

2008 ◽  
Vol 99 (5) ◽  
pp. 2035-2047 ◽  
Author(s):  
Christopher I. Moore ◽  
Rosa Cao
Keyword(s):  
Information Processing ◽  
Neural Activity ◽  
Neural Representation ◽  
Regulatory Control ◽  
Activity Levels ◽  
Functional Hyperemia ◽  
Sensory Stimuli ◽  
Brain Vasculature ◽  
Medical Benefits

Brain vasculature is a complex and interconnected network under tight regulatory control that exists in intimate communication with neurons and glia. Typically, hemodynamics are considered to exclusively serve as a metabolic support system. In contrast to this canonical view, we propose that hemodynamics also play a role in information processing through modulation of neural activity. Functional hyperemia, the basis of the functional MRI (fMRI) BOLD signal, is a localized influx of blood correlated with neural activity levels. Functional hyperemia is considered by many to be excessive from a metabolic standpoint, but may be appropriate if interpreted as having an activity-dependent neuro-modulatory function. Hemodynamics may impact neural activity through direct and indirect mechanisms. Direct mechanisms include delivery of diffusible blood-borne messengers and mechanical and thermal modulation of neural activity. Indirect mechanisms are proposed to act through hemodynamic modulation of astrocytes, which can in turn regulate neural activity. These hemo-neural mechanisms should alter the information processing capacity of active local neural networks. Here, we focus on analysis of neocortical sensory processing. We predict that hemodynamics alter the gain of local cortical circuits, modulating the detection and discrimination of sensory stimuli. This novel view of information processing—that includes hemodynamics as an active and significant participant—has implications for understanding neural representation and the construction of accurate brain models. There are also potential medical benefits of an improved understanding of the role of hemodynamics in neural processing, as it directly bears on interpretation of and potential treatment for stroke, dementia, and epilepsy.

scholarly journals Corticostriatal control of defense behavior in mice induced by auditory looming cues

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhong Li ◽  
Jin-Xing Wei ◽  
Guang-Wei Zhang ◽  
Junxiang J. Huang ◽  
Brian Zingg ◽  
...  
Keyword(s):  
Essential Role ◽  
Neural Circuits ◽  
Temporal Dynamics ◽  
Defense Behavior ◽  
Innate Defense ◽  
Sensory Inputs ◽  
Corticostriatal Projections ◽  
Behavioral Transition ◽  
Auditory Looming

AbstractAnimals exhibit innate defense behaviors in response to approaching threats cued by the dynamics of sensory inputs of various modalities. The underlying neural circuits have been mostly studied in the visual system, but remain unclear for other modalities. Here, by utilizing sounds with increasing (vs. decreasing) loudness to mimic looming (vs. receding) objects, we find that looming sounds elicit stereotypical sequential defensive reactions: freezing followed by flight. Both behaviors require the activity of auditory cortex, in particular the sustained type of responses, but are differentially mediated by corticostriatal projections primarily innervating D2 neurons in the tail of the striatum and corticocollicular projections to the superior colliculus, respectively. The behavioral transition from freezing to flight can be attributed to the differential temporal dynamics of the striatal and collicular neurons in their responses to looming sound stimuli. Our results reveal an essential role of the striatum in the innate defense control.

Fit Perception and Engagement: The Mediating Role of Work Meaningfulness

2021 ◽  
pp. 097226292199986
Author(s):  
Robinson James
Keyword(s):  
Employee Engagement ◽  
Structural Equation ◽  
Strong Predictor ◽  
Organizational Outcomes ◽  
Research Strategy ◽  
Partial Least Square ◽  
Least Square ◽  
Future Research ◽  
Work Meaningfulness

Research on engagement has gained considerable attention in recent years as it is a strong predictor of a range of positive individual and organizational outcomes. There is a question of why the level of the engagement is different from employee to employee in an organization, though they are provided with the same resources. This study aims to investigate the influence of fit perception on engagement and the role of the employee’s psychological condition (work meaningfulness) on this relationship. This study mainly employed a survey research strategy, and data were primarily garnered from a questionnaire. This study was conducted among 145 respondents from the public sector organizations in Sri Lanka. Partial least-square structural equation modelling was employed to analyse the generated data. In this study, the researcher has conceptualized fit perception as a higher order construct comprising Person Job fit and Person Organization fit. The study revealed that fit perception positively influences employee engagement, and this relationship is mediated by work meaningfulness. This study contributes to the literature by deepening the understanding of the fit perception and engagement relationship by introducing work meaningfulness as a mediator variable. By highlighting how engagement is influenced by fit perception and work meaningfulness, this study facilitates practitioners to build and maintain an engaged workforce. Further contributions of this study, the avenue for future research, and study limitations are presented in detail at the end of this article.

scholarly journals Role of chest radiograph in MERS-Cov pneumonia: a single tertiary referral center experience in the United Arab Emirates

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Karuna M. Das ◽  
Jamal Aldeen Alkoteesh ◽  
Mohamud Sheek-Hussein ◽  
Samira Ali Alzadjali ◽  
Mariam Tareq Alafeefi ◽  
...  
Keyword(s):  
Pleural Effusion ◽  
United Arab Emirates ◽  
Chest Radiograph ◽  
Strong Predictor ◽  
Ground Glass ◽  
Tertiary Referral Center ◽  
Unit Management ◽  
Radiographic Score ◽  
Progression Of Disease

Abstract Background The Middle East respiratory syndrome coronavirus (MERS-Cov) continues to be a source of concern due to intermittent outbreaks. Serial chest radiographic changes in MERS-Cov patients were analyzed for various variables that could be compared to the patients’ final outcomes in a cluster of MERS-Cov patients and to identify a predictor of mortality in the United Arab Emirates. Results A total of 44 MERS-Cov cases were reviewed. The mean age of the patients was 43.7 ± 14.7 years. The chest radiograph was abnormal in 14/44 (31.8%). The commonest radiology features include ground-glass opacities (seven of 14, 50%), ground-glass and consolidation (seven of 14, 50%), pleural effusion (eight of 14, 57.1%), and air bronchogram (three of 14, 21.4%). The mortality rate was 13.6% (six of 44); the deceased group (6 of 44, 13.6%) was associated with significantly higher incidence of mechanical ventilation (p < 0.001), pleural effusion (p < 0.001), chest radiographic score (8.90 ± 6.31, p < 0.001), and type 4 radiographic progression of disease (p < 0.001). A chest radiographic score at presentation was seen to be an independent and strong predictor of mortality (OR [95% confidence interval] 3.20 [1.35, 7.61]). The Cohen κ coefficient for the interobserver agreement was k = 0.89 (p = 0.001). Conclusion The chest radiographic score, associated with a higher degree of disease progression (type 4), particularly in patients with old age or with comorbidity, may indicate a poorer prognosis in MERS-Cov infection, necessitating intensive care unit management or predicting impending death.

Role of the Vermal Cerebellum in Visually Guided Eye Movements and Visual Motion Perception

2019 ◽  
Vol 5 (1) ◽  
pp. 247-268 ◽  
Author(s):  
Peter Thier ◽  
Akshay Markanday
Keyword(s):  
Eye Movements ◽  
Motion Perception ◽  
Visual Motion ◽  
Cerebellar Nuclei ◽  
Visually Guided ◽  
Past Performance ◽  
Visual Motion Perception ◽  
Oculomotor Vermis ◽  
Retinal Information

The cerebellar cortex is a crystal-like structure consisting of an almost endless repetition of a canonical microcircuit that applies the same computational principle to different inputs. The output of this transformation is broadcasted to extracerebellar structures by way of the deep cerebellar nuclei. Visually guided eye movements are accommodated by different parts of the cerebellum. This review primarily discusses the role of the oculomotor part of the vermal cerebellum [the oculomotor vermis (OMV)] in the control of visually guided saccades and smooth-pursuit eye movements. Both types of eye movements require the mapping of retinal information onto motor vectors, a transformation that is optimized by the OMV, considering information on past performance. Unlike the role of the OMV in the guidance of eye movements, the contribution of the adjoining vermal cortex to visual motion perception is nonmotor and involves a cerebellar influence on information processing in the cerebral cortex.

scholarly journals Mental Rotation Meets the Motion Aftereffect: The Role of hV5/MT+ in Visual Mental Imagery

2011 ◽  
Vol 23 (6) ◽  
pp. 1395-1404 ◽  
Author(s):  
Ruth Seurinck ◽  
Floris P. de Lange ◽  
Erik Achten ◽  
Guy Vingerhoets
Keyword(s):  
Mental Rotation ◽  
Mental Imagery ◽  
Parietal Cortex ◽  
Neural Activity ◽  
Posterior Parietal Cortex ◽  
Visual Motion ◽  
Motion Aftereffect ◽  
Mental Rotation Task ◽  
Behavioral Performance ◽  
Visual Mental Imagery

A growing number of studies show that visual mental imagery recruits the same brain areas as visual perception. Although the necessity of hV5/MT+ for motion perception has been revealed by means of TMS, its relevance for motion imagery remains unclear. We induced a direction-selective adaptation in hV5/MT+ by means of an MAE while subjects performed a mental rotation task that elicits imagined motion. We concurrently measured behavioral performance and neural activity with fMRI, enabling us to directly assess the effect of a perturbation of hV5/MT+ on other cortical areas involved in the mental rotation task. The activity in hV5/MT+ increased as more mental rotation was required, and the perturbation of hV5/MT+ affected behavioral performance as well as the neural activity in this area. Moreover, several regions in the posterior parietal cortex were also affected by this perturbation. Our results show that hV5/MT+ is required for imagined visual motion and engages in an interaction with parietal cortex during this cognitive process.

Sign in / Sign up

Export Citation Format

Share Document