scholarly journals Effects of visual inputs on neural dynamics for coding of location and running speed in medial entorhinal cortex

2020 ◽  
Author(s):  
Holger Dannenberg ◽  
Hallie Lazaro ◽  
Pranav Nambiar ◽  
Alec Hoyland ◽  
Michael E. Hasselmo

ABSTRACTNeuronal representations of spatial location and movement speed in the medial entorhinal cortex during the “active” theta state of the brain are important for memory-guided navigation and rely on visual inputs. However, little is known about how visual inputs change neural dynamics as a function of running speed and time. By manipulating visual inputs in mice, we demonstrate that changes in spatial stability of grid cell firing as a function of time correlate with changes in a proposed speed signal by local field potential theta frequency. In contrast, visual inputs do not affect the speed modulation of firing rates. Moreover, we provide evidence that sensory inputs other than visual inputs can support grid cell firing, though less accurately, in complete darkness. Finally, changes in spatial accuracy of grid cell firing on a 10-s time scale suggest that grid cell firing is a function of velocity signals integrated over past time.

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Holger Dannenberg ◽  
Hallie Lazaro ◽  
Pranav Nambiar ◽  
Alec Hoyland ◽  
Michael E Hasselmo

Neuronal representations of spatial location and movement speed in the medial entorhinal cortex during the ‘active’ theta state of the brain are important for memory-guided navigation and rely on visual inputs. However, little is known about how visual inputs change neural dynamics as a function of running speed and time. By manipulating visual inputs in mice, we demonstrate that changes in spatial stability of grid cell firing correlate with changes in a proposed speed signal by local field potential theta frequency. In contrast, visual inputs do not alter the running speed-dependent gain in neuronal firing rates. Moreover, we provide evidence that sensory inputs other than visual inputs can support grid cell firing, though less accurately, in complete darkness. Finally, changes in spatial accuracy of grid cell firing on a 10 s time scale suggest that grid cell firing is a function of velocity signals integrated over past time.


2014 ◽  
Vol 369 (1635) ◽  
pp. 20120523 ◽  
Author(s):  
Michael E. Hasselmo

Data show a relationship of cellular resonance and network oscillations in the entorhinal cortex to the spatial periodicity of grid cells. This paper presents a model that simulates the resonance and rebound spiking properties of entorhinal neurons to generate spatial periodicity dependent upon phasic input from medial septum. The model shows that a difference in spatial periodicity can result from a difference in neuronal resonance frequency that replicates data from several experiments. The model also demonstrates a functional role for the phenomenon of theta cycle skipping in the medial entorhinal cortex.


2014 ◽  
Vol 369 (1635) ◽  
pp. 20120520 ◽  
Author(s):  
Christoph Schmidt-Hieber ◽  
Michael Häusser

Neurons in the medial entorhinal cortex fire action potentials at regular spatial intervals, creating a striking grid-like pattern of spike rates spanning the whole environment of a navigating animal. This remarkable spatial code may represent a neural map for path integration. Recent advances using patch-clamp recordings from entorhinal cortex neurons in vitro and in vivo have revealed how the microcircuitry in the medial entorhinal cortex may contribute to grid cell firing patterns, and how grid cells may transform synaptic inputs into spike output during firing field crossings. These new findings provide key insights into the ingredients necessary to build a grid cell.


Neuron ◽  
2008 ◽  
Vol 60 (5) ◽  
pp. 875-889 ◽  
Author(s):  
Derek L.F. Garden ◽  
Paul D. Dodson ◽  
Cian O'Donnell ◽  
Melanie D. White ◽  
Matthew F. Nolan

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Ipshita Zutshi ◽  
Maylin L. Fu ◽  
Varoth Lilascharoen ◽  
Jill K. Leutgeb ◽  
Byung Kook Lim ◽  
...  

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