The Representation of Space and the Hippocampus in Rats, Robots and Humans

1998 ◽  
Vol 53 (7-8) ◽  
pp. 504-509 ◽  
Author(s):  
Neil Burgess ◽  
James G. Donnett ◽  
John O ’Keefe
Keyword(s):  
Mobile Robot ◽  
Firing Rate ◽  
Path Integration ◽  
Theta Rhythm ◽  
Place Cells ◽  
System A ◽  
Representation Of Space ◽  
Rate Coding ◽  
Use Phase

Abstract Experimental evidence suggests that the hippocampus represents locations within an allocentric representation of space. The environmental inputs that underlie the rat’s representa­tion of its own location within an environment (in the firing of place cells) are the distances to walls, and different walls are identified by their allocentric direction from the rat. We propose that the locations of goals in an environment is stored downstream of the place cells, in the subiculum. In addition to firing rate coding, place cells may use phase coding relative to the theta rhythm of the EEG. In some circumstances path integration may be used, in addition to environmental information, as an input to the hippocampal system. A detailed computational model of the hippocampus successfully guides the navigation of a mobile robot. The model’s behaviour is compared to electrophysiological and behavioural data in rats, and implications for the role of the hippocampus in primates are explored.

scholarly journals Independent theta phase coding accounts for CA1 population sequences and enables flexible remapping

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Angus Chadwick ◽  
Mark CW van Rossum ◽  
Matthew F Nolan
Keyword(s):  
Traveling Wave ◽  
Action Potentials ◽  
Theta Rhythm ◽  
Place Cells ◽  
Population Activity ◽  
Phase Coding ◽  
Synaptic Interactions ◽  
Spike Sequences ◽  
Rate Coding ◽  
Theta Phase

Hippocampal place cells encode an animal's past, current, and future location through sequences of action potentials generated within each cycle of the network theta rhythm. These sequential representations have been suggested to result from temporally coordinated synaptic interactions within and between cell assemblies. Instead, we find through simulations and analysis of experimental data that rate and phase coding in independent neurons is sufficient to explain the organization of CA1 population activity during theta states. We show that CA1 population activity can be described as an evolving traveling wave that exhibits phase coding, rate coding, spike sequences and that generates an emergent population theta rhythm. We identify measures of global remapping and intracellular theta dynamics as critical for distinguishing mechanisms for pacemaking and coordination of sequential population activity. Our analysis suggests that, unlike synaptically coupled assemblies, independent neurons flexibly generate sequential population activity within the duration of a single theta cycle.

scholarly journals Asymmetry of the temporal code for space by hippocampal place cells

2016 ◽  
Author(s):  
Bryan C. Souza ◽  
Adriano B. L. Tort
Keyword(s):  
Firing Rate ◽  
Spatial Information ◽  
Place Cells ◽  
Spike Timing ◽  
Temporal Coding ◽  
Place Field ◽  
Phase Precession ◽  
Wide Debate ◽  
Rate Coding ◽  
Theta Phase

Hippocampal place cells convey spatial information through spike frequency (“rate coding”) and spike timing relative to the theta phase (“temporal coding”). Whether rate and temporal coding are due to independent or related mechanisms has been the subject of wide debate. Here we show that the spike timing of place cells couples to theta phase before major increases in firing rate, anticipating the animal’s entrance into the classical, rate-based place field. In contrast, spikes rapidly decouple from theta as the animal leaves the place field and firing rate decreases. Therefore, temporal coding has strong asymmetry around the place field center. We further show that the dynamics of temporal coding along space evolves in three stages: phase coupling, phase precession and phase decoupling. These results suggest that place cells represent more future than past locations through their spike timing and that independent mechanisms govern rate and temporal coding.

scholarly journals Are There Place Cells in the Avian Hippocampus?

2017 ◽  
Vol 90 (1) ◽  
pp. 73-80 ◽  
Author(s):  
David F. Sherry ◽  
Stephanie L. Grella ◽  
Mélanie F. Guigueno ◽  
David J. White ◽  
Diano F. Marrone
Keyword(s):  
Brain Research ◽  
Brain Regions ◽  
Place Cells ◽  
Early Gene ◽  
Head Direction ◽  
Representation Of Space ◽  
Spatial Environment ◽  
Neuronal Representation ◽  
Avian Hippocampus

Birds possess a hippocampus that serves many of the same spatial and mnemonic functions as the mammalian hippocampus but achieves these outcomes with a dramatically different neuroanatomical organization. The properties of spatially responsive neurons in birds and mammals are also different. Much of the contemporary interest in the role of the mammalian hippocampus in spatial representation dates to the discovery of place cells in the rat hippocampus. Since that time, cells that respond to head direction and cells that encode a grid-like representation of space have been described in the rat brain. Research with homing pigeons has discovered hippocampal cells, including location cells, path cells, and pattern cells, that share some but not all properties of spatially responsive neurons in the rodent brain. We have recently used patterns of immediate-early gene expression, visualized by the catFISH method, to investigate how neurons in the hippocampus of brood-parasitic brown-headed cowbirds respond to spatial context. We have found cells that discriminate between different spatial environments and are re-activated when the same spatial environment is re-experienced. Given the differences in habitat and behaviour between birds and rodents, it is not surprising that spatially responsive cells in their hippocampus and other brain regions differ. The enormous diversity of avian habitats and behaviour offers the potential for understanding the general principles of neuronal representation of space.

scholarly journals Independent Theta Phase Coding Accounts for CA1 Population Sequences and Enables Flexible Remapping

2014 ◽  
Author(s):  
Angus Chadwick ◽  
Mark C. W. van Rossum ◽  
Matthew F. Nolan
Keyword(s):  
Action Potentials ◽  
Theta Rhythm ◽  
Place Cells ◽  
Population Activity ◽  
Phase Coding ◽  
Synaptic Interactions ◽  
Spike Sequences ◽  
Rate Coding ◽  
Theta Phase ◽  
Flexible Generation

Populations of hippocampal place cells encode an animal's past, current and future location through sequences of action potentials generated within each cycle of the network theta rhythm. These sequential representations have been suggested to result from temporally coordinated synaptic interactions within and between cell assemblies. In contrast, we show that a model based on rate and phase coding in independent neurons is sufficient to explain the organization of CA1 population activity during theta states. We show that CA1 population activity can be described as an evolving traveling wave that exhibits phase coding, rate coding, spike sequences and that generates an emergent population theta rhythm. We identify measures of global remapping and intracellular theta dynamics as critical for distinguishing mechanisms for pacemaking and coordination of sequential population activity. Our analysis suggests that independent coding enables flexible generation of sequential population activity within the duration of a single theta cycle.

The SORS Decision-Making Support System: A statistical tool for better policy making in the Republic of Serbia

2021 ◽  
pp. 1-11
Author(s):  
Miladin Kovačević ◽  
Katarina Stančić
Keyword(s):  
Policy Making ◽  
Modern Society ◽  
Monitoring And Evaluation ◽  
Public Debate ◽  
Statistical Tool ◽  
The Public ◽  
System A ◽  
The Republic ◽  
Trusted Data

Modern society is witnessing a data revolution which necessarily entails changes to the overall behavior of citizens, governments and companies. This is a big challenge and an opportunity for National Statistics Offices (NSOs). Especially after the outbreak of COVID-19, when the public debate about the number of mortalities and tested and infected persons escalated, trusted data is required more than ever. Which data can modern society trust? Are modern societies being subjected to opinion rather than fact? This paper introduces a new statistical tool to facilitate policy-making based on trusted statistics. Using economic indicators to illustrate implementation, the new statistical tool is shown to be a flexible instrument for analysis, monitoring and evaluation of the economic situation in the Republic of Serbia. By taking a role in public policy management, the tool can be used to transform the NSO’s role in the statistical system into an active participant in public debate in contrast to the previous traditional, usually passive role of collecting, processing and publishing data. The tool supports the integration of statistics into public policies and connects the knowledge and expertise of official statisticians on one side with political decision makers on the other.

scholarly journals Prenatal and Perinatal Environmental Influences Shaping the Neonatal Immune System: A Focus on Asthma and Allergy Origins

2021 ◽  
Vol 18 (8) ◽  
pp. 3962
Author(s):  
Azahara María García-Serna ◽  
Elena Martín-Orozco ◽  
Trinidad Hernández-Caselles ◽  
Eva Morales
Keyword(s):  
Immune System ◽  
Immune Cell ◽  
Mode Of Delivery ◽  
Environmental Influences ◽  
Pet Ownership ◽  
System A ◽  
Neonatal Immune System ◽  
Chemical Factors ◽  
Asthma And Allergy

It is suggested that programming of the immune system starts before birth and is shaped by environmental influences acting during critical windows of susceptibility for human development. Prenatal and perinatal exposure to physiological, biological, physical, or chemical factors can trigger permanent, irreversible changes to the developing immune system, which may be reflected in cord blood of neonates. The aim of this narrative review is to summarize the evidence on the role of the prenatal and perinatal environment, including season of birth, mode of delivery, exposure to common allergens, a farming environment, pet ownership, and exposure to tobacco smoking and pollutants, in shaping the immune cell populations and cytokines at birth in humans. We also discuss how reported disruptions in the immune system at birth might contribute to the development of asthma and related allergic manifestations later in life.

scholarly journals The Relevance of the SH2 Domain for c-Src Functionality in Triple-Negative Breast Cancer Cells

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 462
Author(s):  
Víctor Mayoral-Varo ◽  
María Pilar Sánchez-Bailón ◽  
Annarica Calcabrini ◽  
Marta García-Hernández ◽  
Valerio Frezza ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Sh2 Domain ◽  
Model Systems ◽  
System A ◽  
Promising Therapeutic Target ◽  
Relevant Role ◽  
Inactivating Mutation

The role of Src family kinases (SFKs) in human tumors has been always associated with tyrosine kinase activity and much less attention has been given to the SH2 and SH3 adapter domains. Here, we studied the role of the c-Src-SH2 domain in triple-negative breast cancer (TNBC). To this end, SUM159PT and MDA-MB-231 human cell lines were employed as model systems. These cells conditionally expressed, under tetracycline control (Tet-On system), a c-Src variant with point-inactivating mutation of the SH2 adapter domain (R175L). The expression of this mutant reduced the self-renewal capability of the enriched population of breast cancer stem cells (BCSCs), demonstrating the importance of the SH2 adapter domain of c-Src in the mammary gland carcinogenesis. In addition, the analysis of anchorage-independent growth, proliferation, migration, and invasiveness, all processes associated with tumorigenesis, showed that the SH2 domain of c-Src plays a very relevant role in their regulation. Furthermore, the transfection of two different aptamers directed to SH2-c-Src in both SUM159PT and MDA-MB-231 cells induced inhibition of their proliferation, migration, and invasiveness, strengthening the hypothesis that this domain is highly involved in TNBC tumorigenesis. Therefore, the SH2 domain of c-Src could be a promising therapeutic target and combined treatments with inhibitors of c-Src kinase enzymatic activity may represent a new therapeutic strategy for patients with TNBC, whose prognosis is currently very negative.

Identification and Model Predictive Position Control of Two Wheeled Inverted Pendulum Mobile Robot

2015 ◽  
Vol 73 (6) ◽  
Author(s):  
Amir A. Bature ◽  
Salinda Buyamin ◽  
Mohamad N. Ahmad ◽  
Mustapha Muhammad ◽  
Auwalu A. Muhammad
Keyword(s):  
Mathematical Model ◽  
System Identification ◽  
Mobile Robot ◽  
Inverted Pendulum ◽  
Position Control ◽  
Superior Performance ◽  
System A ◽  
Wheeled Inverted Pendulum ◽  
Simulation Results ◽  
Real Plant

In order to predict and analyse the behaviour of a real system, a simulated model is needed. The more accurate the model the better the response is when dealing with the real plant. This paper presents a model predictive position control of a Two Wheeled Inverted Pendulum robot. The model was developed by system identification using a grey box technique. Simulation results show superior performance of the gains computed using the grey box model as compared to common linearized mathematical model. 

scholarly journals Circulating Secretin Activates Supraoptic Nucleus Oxytocin and Vasopressin Neurons via Noradrenergic Pathways in the Rat

Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2681-2688 ◽  
Author(s):  
Sathya Velmurugan ◽  
Paula J. Brunton ◽  
Gareth Leng ◽  
John A. Russell
Keyword(s):  
Amino Acid ◽  
Firing Rate ◽  
Noradrenaline Release ◽  
Supraoptic Nucleus ◽  
Female Rats ◽  
Adrenoceptor Antagonist ◽  
Intracerebroventricular Infusion ◽  
Neuroendocrine Neurons ◽  
Vasopressin Neurons

Secretin is a 27-amino acid brain-gut peptide from duodenal S-cells. We tested the effects of systemic administration of secretin to simulate its postprandial release on neuroendocrine neurons of the supraoptic nucleus (SON) in urethane-anesthetized female rats. Secretin dose-dependently increased the firing rate of oxytocin neurons, more potently than cholecystokinin, and dose-dependently increased plasma oxytocin concentration. The effect of secretin on SON vasopressin neurons was also predominantly excitatory, in contrast to the inhibitory actions of cholecystokinin. To explore the involvement of noradrenergic inputs in secretin-induced excitation, benoxathian, an α1-adrenoceptor antagonist, was infused intracerebroventricularly. Benoxathian intracerebroventricular infusion blocked the excitation by secretin of both oxytocin and vasopressin neurons. To test the role of local noradrenaline release in the SON, benoxathian was microdialyzed onto the SON. The basal firing rate of oxytocin neurons was slightly reduced and the secretin-induced excitation was attenuated during benoxathian microdialysis. Hence, noradrenergic pathways mediate the excitation by systemic secretin of oxytocin neurons via α1-adrenoceptors in the SON. As both systemic secretin and oxytocin are involved in regulating gastrointestinal functions and natriuresis, systemically released secretin might act partly through oxytocin.

Sign in / Sign up

Export Citation Format

Share Document