Role of cortical feedback in the receptive field structure and nonlinear response properties of somatosensory thalamic neurons

2001 ◽  
Vol 141 (1) ◽  
pp. 88-100 ◽  
Author(s):  
Asif Ghazanfar ◽  
David Krupa ◽  
Miguel Nicolelis
Keyword(s):  
Receptive Field ◽  
Nonlinear Response ◽  
Field Structure ◽  
Thalamic Neurons ◽  
Response Properties ◽  
Cortical Feedback

DEVELOPMENT OF FEEDFORWARD RECEPTIVE FIELD STRUCTURE OF A SIMPLE CELL AND ITS CONTRIBUTION TO THE ORIENTATION SELECTIVITY: A MODELING STUDY

2005 ◽  
Vol 15 (01n02) ◽  
pp. 55-70 ◽  
Author(s):  
AKHIL R GARG ◽  
KLAUS OBERMAYER ◽  
BASABI BHAUMIK
Keyword(s):  
Receptive Field ◽  
Field Structure ◽  
Orientation Selectivity ◽  
Simple Cell ◽  
Homogeneous State ◽  
Synaptic Efficacy ◽  
Synaptic Interactions ◽  
Experimental Findings ◽  
Modeling Study

Recent experimental studies of hetero-synaptic interactions in various systems have shown the role of signaling in the plasticity, challenging the conventional understanding of Hebb's rule. It has also been found that activity plays a major role in plasticity, with neurotrophins acting as molecular signals translating activity into structural changes. Furthermore, role of synaptic efficacy in biasing the outcome of competition has also been revealed recently. Motivated by these experimental findings we present a model for the development of simple cell receptive field structure based on the competitive hetero-synaptic interactions for neurotrophins combined with cooperative hetero-synaptic interactions in the spatial domain. We find that with proper balance in competition and cooperation, the inputs from two populations (ON/OFF) of LGN cells segregate starting from the homogeneous state. We obtain segregated ON and OFF regions in simple cell receptive field. Our modeling study supports the experimental findings, suggesting the role of synaptic efficacy and the role of spatial signaling. We find that using this model we obtain simple cell RF, even for positively correlated activity of ON/OFF cells. We also compare different mechanism of finding the response of cortical cell and study their possible role in the sharpening of orientation selectivity. We find that degree of selectivity improvement in individual cells varies from case to case depending upon the structure of RF field and type of sharpening mechanism.

scholarly journals Synaptic Contributions to Receptive Field Structure and Response Properties in the Rodent Lateral Geniculate Nucleus of the Thalamus

2016 ◽  
Vol 36 (43) ◽  
pp. 10949-10963 ◽  
Author(s):  
V. Suresh ◽  
U. M. Ciftcio lu ◽  
X. Wang ◽  
B. M. Lala ◽  
K. R. Ding ◽  
...  
Keyword(s):  
Receptive Field ◽  
Lateral Geniculate Nucleus ◽  
Field Structure ◽  
Response Properties ◽  
Lateral Geniculate

scholarly journals Receptive Fields and Response Properties of Neurons in Layer 4 of Ferret Visual Cortex

2003 ◽  
Vol 89 (2) ◽  
pp. 1003-1015 ◽  
Author(s):  
W. Martin Usrey ◽  
Michael P. Sceniak ◽  
Barbara Chapman
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Receptive Fields ◽  
Field Structure ◽  
Orientation Selectivity ◽  
Stimulus Orientation ◽  
Orientation Tuning ◽  
Simple Cells ◽  
Response Properties ◽  
Layer 4

The ferret has become a model animal for studies exploring the development of the visual system. However, little is known about the receptive-field structure and response properties of neurons in the adult visual cortex of the ferret. We performed single-unit recordings from neurons in layer 4 of adult ferret primary visual cortex to determine the receptive-field structure and visual-response properties of individual neurons. In particular, we asked what is the spatiotemporal structure of receptive fields of layer 4 neurons and what is the orientation selectivity of layer 4 neurons? Receptive fields of layer 4 neurons were mapped using a white-noise stimulus; orientation selectivity was determined using drifting, sine-wave gratings. Our results show that most neurons (84%) within layer 4 are simple cells with elongated, spatially segregated,on and off subregions. These neurons are also selective for stimulus orientation; peaks in orientation-tuning curves have, on average, a half-width at half-maximum response of 21.5 ± 1.2° (mean ± SD). The remaining neurons in layer 4 (16%) lack orientation selectivity and have center/surround receptive fields. Although the organization of geniculate inputs to layer 4 differs substantially between ferret and cat, our results demonstrate that, like in the cat, most neurons in ferret layer 4 are orientation-selective simple cells.

scholarly journals What Density of Magnetosheath Sodium Ions Can Provide the Observed Decrease in the Magnetic Field of the “Double Magnetopause” during the First MESSENGER Flyby?

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1168
Author(s):  
Elena Belenkaya ◽  
Ivan Pensionerov
Keyword(s):  
Magnetic Field ◽  
Analytical Approach ◽  
Field Structure ◽  
Sodium Ions ◽  
Plasma Parameters ◽  
Calculation Results ◽  
Magnetizing Current ◽  
The Magnetic Field ◽  
Density Excess

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.

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