scholarly journals Circuit Models of Low-Dimensional Shared Variability in Cortical Networks

Neuron ◽  
2019 ◽  
Vol 101 (2) ◽  
pp. 337-348.e4 ◽  
Author(s):  
Chengcheng Huang ◽  
Douglas A. Ruff ◽  
Ryan Pyle ◽  
Robert Rosenbaum ◽  
Marlene R. Cohen ◽  
...  
Keyword(s):  
Cortical Networks ◽  
Low Dimensional

scholarly journals Circuit models of low dimensional shared variability in cortical networks

2017 ◽  
Author(s):  
Chengcheng Huang ◽  
Douglas A. Ruff ◽  
Ryan Pyle ◽  
Robert Rosenbaum ◽  
Marlene R. Cohen ◽  
...  
Keyword(s):  
Brain Area ◽  
Inhibitory Neurons ◽  
Cortical Circuits ◽  
Cortical Networks ◽  
Visual Neurons ◽  
Spatial And Temporal Scales ◽  
External Sources ◽  
Inhibitory Coupling ◽  
Low Dimensional

AbstractTrial-to-trial variability is a reflection of the circuitry and cellular physiology that makeup a neuronal network. A pervasive yet puzzling feature of cortical circuits is that despite their complex wiring, population-wide shared spiking variability is low dimensional with all neurons fluctuating en masse. Previous model cortical networks are at loss to explain this global variability, and rather assume it is from external sources. We show that if the spatial and temporal scales of inhibitory coupling match known physiology, model spiking neurons internally generate low dimensional shared variability that captures the properties of in vivo population recordings along the visual pathway. Shifting spatial attention into the receptive field of visual neurons has been shown to reduce low dimensional shared variability within a brain area, yet increase the variability shared between areas. A top-down modulation of inhibitory neurons in our network provides a parsimonious mechanism for this attentional modulation, providing support for our theory of cortical variability. Our work provides a critical and previously missing mechanistic link between observed cortical circuit structure and realistic population-wide shared neuronal variability and its modulation.

Thermoelectric Properties of PbSr(Se,Te)-Based Low Dimensional Structures

2000 ◽  
Vol 626 ◽  
Author(s):  
Harald Beyer ◽  
Joachim Nurnus ◽  
Harald Böttner ◽  
Armin Lambrecht ◽  
Lothar Schmitt ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Evaluation Method ◽  
Interband Transition ◽  
Multiple Quantum Well ◽  
Calculated Data ◽  
Multiple Quantum ◽  
Ir Transmission ◽  
Low Dimensional

ABSTRACTThermoelectric properties of low dimensional structures based on PbTe/PbSrTe-multiple quantum-well (MQW)-structures with regard to the structural dimensions, doping profiles and levels are presented. Interband transition energies and barrier band-gap are determined from IR-transmission spectra and compared with Kronig-Penney calculations. The influence of the data evaluation method to obtain the 2D power factor will be discussed. The thermoelectrical data of our layers show a more modest enhancement in the power factor σS2 compared with former publications and are in good agreement with calculated data from Broido et al. [5]. The maximum allowed doping level for modulation doped MQW structures is determined. Thermal conductivity measurements show that a ZT enhancement can be achieved by reducing the thermal conductivity due to interface scattering. Additionally promising lead chalcogenide based superlattices for an increased 3D figure of merit are presented.

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