scholarly journals Medial entorhinal cortex activates in a traveling wave

2019 ◽  
Author(s):  
J.J. Hernández-Pérez ◽  
K.W. Cooper ◽  
E.L. Newman
Keyword(s):  
Information Processing ◽  
Entorhinal Cortex ◽  
Traveling Waves ◽  
Traveling Wave ◽  
Field Potential ◽  
Cortical Activity ◽  
Phase Shifts ◽  
Medial Entorhinal Cortex ◽  
Theta Phase ◽  
Cortical Information Processing

SummaryTraveling waves of cortical activity are hypothesized to organize cortical information processing and support interregional communication. Yet, it remains unknown whether interacting areas exhibit the matched traveling waves necessary to support this hypothesized form of interaction. Here, we show that the strongly-interacting medial entorhinal cortex (MEC) and hippocampus exhibit matched traveling waves. We demonstrate that both the field potential and spiking in the MEC exhibit prominent 6-12 Hz ‘theta’ traveling waves matching those of the hippocampus. The theta phase shifts observed along the MEC were accounted for largely by variation in waveform asymmetry. From this, we hypothesize that that gradients in local physiology underlie both the generation of MEC traveling waves and the functional variations observed previously across the MEC.

scholarly journals Medial entorhinal cortex activates in a traveling wave in the rat

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
J Jesús Hernández-Pérez ◽  
Keiland W Cooper ◽  
Ehren L Newman
Keyword(s):  
Entorhinal Cortex ◽  
Traveling Waves ◽  
Traveling Wave ◽  
Phase Shifts ◽  
Medial Entorhinal Cortex ◽  
Theta Waves ◽  
Residual Phase ◽  
Weakly Coupled ◽  
Theta Frequency ◽  
Distributed Circuits

Traveling waves are hypothesized to support the long-range coordination of anatomically distributed circuits. Whether separate strongly interacting circuits exhibit traveling waves remains unknown. The hippocampus exhibits traveling ‘theta’ waves and interacts strongly with the medial entorhinal cortex (MEC). To determine whether the MEC also activates in a traveling wave, we performed extracellular recordings of local field potentials (LFP) and multi-unit activity along the MEC. These recordings revealed progressive phase shifts in activity, indicating that the MEC also activates in a traveling wave. Variation in theta waveform along the region, generated by gradients in local physiology, contributed to the observed phase shifts. Removing waveform-related phase shifts left significant residual phase shifts. The residual phase shifts covaried with theta frequency in a manner consistent with those generated by weakly coupled oscillators. These results show that the coordination of anatomically distributed circuits could be enabled by traveling waves but reveal heterogeneity in the mechanisms generating those waves.

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
Keyword(s):  
Entorhinal Cortex ◽  
Field Potential ◽  
Grid Cell ◽  
Spatial Location ◽  
Neural Dynamics ◽  
Movement Speed ◽  
Running Speed ◽  
Medial Entorhinal Cortex ◽  
Visual Inputs ◽  
Cell Firing

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.

scholarly journals Dentate Gyrus and CA3 GABAergic Interneurons Bidirectionally Modulate Signatures of Internal and External Drive to CA1

2021 ◽  
Author(s):  
Emily A. Aery Jones ◽  
Antara Rao ◽  
Misha Zilberter ◽  
Biljana Djukic ◽  
Anna K. Gillespie ◽  
...  
Keyword(s):  
Information Processing ◽  
Dentate Gyrus ◽  
Entorhinal Cortex ◽  
Local Field ◽  
Opposite Effect ◽  
Field Potential ◽  
Gabaergic Neurons ◽  
Gabaergic Interneurons ◽  
Flow Of Information ◽  
The Brain

SUMMARYSpecific classes of GABAergic neurons are thought to play specific roles in regulating information processing in the brain. In the hippocampus, two major classes – parvalbumin-expressing (PV+) and somatostatin-expressing (SST+) neurons – differentially regulate endogenous firing patterns and target different subcellular compartments of principal cells, but how these classes regulate the flow of information throughout the hippocampus is poorly understood. We hypothesized that PV+ and SST+ interneurons in the dentate gyrus (DG) and CA3 might differentially modulate CA3 patterns of output, thereby altering the influence of CA3 on CA1. We found that while suppressing either interneuron type increased DG and CA3 output, the effects on CA1 were very different. Suppressing PV+ interneurons increased local field potential signatures of coupling from CA3 to CA1 and decreased signatures of coupling from entorhinal cortex to CA1; suppressing SST+ interneurons had the opposite effect. Thus, DG and CA3 PV+ and SST+ interneurons bidirectionally modulate the flow of information through the hippocampal circuit.

scholarly journals Potent depression of stimulus evoked field potential responses in the medial entorhinal cortex by serotonin

1999 ◽  
Vol 128 (1) ◽  
pp. 248-254 ◽  
Author(s):  
Dietmar Schmitz ◽  
Tengis Gloveli ◽  
Ruth M Empson ◽  
Uwe Heinemann
Keyword(s):  
Entorhinal Cortex ◽  
Field Potential ◽  
Medial Entorhinal Cortex

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

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Holger Dannenberg ◽  
Hallie Lazaro ◽  
Pranav Nambiar ◽  
Alec Hoyland ◽  
Michael E Hasselmo
Keyword(s):  
Entorhinal Cortex ◽  
Field Potential ◽  
Grid Cell ◽  
Neuronal Firing ◽  
Neural Dynamics ◽  
Movement Speed ◽  
Running Speed ◽  
Medial Entorhinal Cortex ◽  
Visual Inputs ◽  
Cell Firing

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.

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