scholarly journals Identification of the current generator underlying cholinergically induced gamma frequency field potential oscillations in the hippocampal CA3 region

2010 ◽  
Vol 588 (5) ◽  
pp. 785-797 ◽  
Author(s):  
Iris Oren ◽  
Norbert Hájos ◽  
Ole Paulsen
Keyword(s):  
Field Potential ◽  
Current Generator ◽  
Potential Oscillations ◽  
Frequency Field ◽  
Gamma Frequency ◽  
Hippocampal Ca3 ◽  
Ca3 Region

scholarly journals Impaired speed encoding and grid cell periodicity in a mouse model of tauopathy

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Thomas Ridler ◽  
Jonathan Witton ◽  
Keith G Phillips ◽  
Andrew D Randall ◽  
Jonathan T Brown
Keyword(s):  
Mouse Model ◽  
Field Potential ◽  
Grid Cell ◽  
Neural Representation ◽  
Running Speed ◽  
Potential Oscillations ◽  
Gamma Frequency ◽  
Rate Coding ◽  
Velocity Information ◽  
Direction Tuning

Dementia is associated with severe spatial memory deficits which arise from dysfunction in hippocampal and parahippocampal circuits. For spatially sensitive neurons, such as grid cells, to faithfully represent the environment these circuits require precise encoding of direction and velocity information. Here, we have probed the firing rate coding properties of neurons in medial entorhinal cortex (MEC) in a mouse model of tauopathy. We find that grid cell firing patterns are largely absent in rTg4510 mice, while head-direction tuning remains largely intact. Conversely, neural representation of running speed information was significantly disturbed, with smaller proportions of MEC cells having firing rates correlated with locomotion in rTg4510 mice. Additionally, the power of local field potential oscillations in the theta and gamma frequency bands, which in wild-type mice are tightly linked to running speed, was invariant in rTg4510 mice during locomotion. These deficits in locomotor speed encoding likely severely impact path integration systems in dementia.

scholarly journals Impaired speed encoding is associated with reduced grid cell periodicity in a mouse model of tauopathy

2019 ◽  
Author(s):  
Thomas Ridler ◽  
Jonathan Witton ◽  
Keith G. Phillips ◽  
Andrew D. Randall ◽  
Jonathan T. Brown
Keyword(s):  
Mouse Model ◽  
Field Potential ◽  
Grid Cell ◽  
Neural Representation ◽  
Running Speed ◽  
Potential Oscillations ◽  
Gamma Frequency ◽  
Rate Coding ◽  
Velocity Information ◽  
Direction Tuning

AbstractDementia is associated with severe spatial memory deficits which arise from dysfunction in hippocampal and parahippocampal circuits. For spatially-sensitive neurons, such as grid cells, to faithfully represent the environment these circuits require precise encoding of direction and velocity information. Here we have probed the firing rate coding properties of neurons in medial entorhinal cortex (MEC) in a mouse model of tauopathy. We find that grid cell firing patterns are largely absent in rTg4510 mice, while head direction tuning remains largely intact. Conversely, neural representation of running speed information was significantly disturbed, with smaller proportions of MEC cells having firing rates correlated with locomotion in rTg4510 mice. Additionally, the power of local field potential oscillations in the theta and gamma frequency bands, which in wildtype mice are tightly linked to running speed, was invariant in rTg4510 mice. These deficits in locomotor speed encoding likely severely impact path integration systems in dementia.

The dendritic origins of penicillin-induced epileptogenesis in CA3 hippocampal pyramidal cells

1986 ◽  
Vol 56 (6) ◽  
pp. 1718-1738 ◽  
Author(s):  
J. W. Swann ◽  
R. J. Brady ◽  
R. J. Friedman ◽  
E. J. Smith
Keyword(s):  
Cell Body ◽  
Average Distance ◽  
Hippocampal Slices ◽  
Current Source ◽  
Field Potential ◽  
Pyramidal Cells ◽  
Large Current ◽  
Hippocampal Ca3 ◽  
Ca3 Pyramidal Cells ◽  
Negative Field

Experiments were performed in order to identify the sites of epileptiform burst generation in rat hippocampal CA3 pyramidal cells. A subsequent slow field potential was studied, which is associated with afterdischarge generation. Laminar field potential and current source-density (CSD) methods were employed in hippocampal slices exposed to penicillin. Simultaneous intracellular and extracellular field recordings from the CA3 pyramidal cell body layer showed that whenever an epileptiform burst was recorded extracellularly, individual CA3 neurons underwent an intense depolarization shift. In extracellular records a slow negative field potential invariably followed epileptiform burst generation. In approximately 10% of slices, synchronous afterdischarges rode on the envelope of this negative field potential. Intracellularly a depolarizing afterpotential followed the depolarization shift and was coincident with the extracellular slow negative field potential. A one-dimensional CSD analysis performed perpendicular to the CA3 cell body layer showed that during epileptiform burst generation large current sinks occur simultaneously in the central portions of both the apical and basilar dendrites. The average distance of the peak amplitude for these sinks from the center of the cell body layer was 175 +/- 46.8 microns and 158 +/- 25.0 microns, respectively. A large current source was recorded in the cell body layer. Smaller current sources were observed in the distal portions of the dendritic layers. During the postburst slow field potential a current sink was recorded at the edge of the cell body layer in stratum oriens--a region referred to as the infrapyramidal zone. Simultaneous with the current sink recorded there, smaller sinks were often observed in the dendritic layers that appeared to be "tails" or prolongations of the currents underlying burst generation. Two-dimensional analyses of these field potentials were performed on planes parallel and perpendicular to the exposed surface of the slice. Isopotential contours showed that the direction of extracellular current is mainly orthogonal to the CA3 laminae. Correction of CSD estimates made perpendicular to the cell body layer for current flowing in the other direction did not alter the location of computed current sources and sinks. In order to show that the dendritic currents associated with epileptiform burst generation were active sinks, tetrodotoxin (TTX) was applied locally to the dendrites where the current sinks were recorded.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals FK960, a novel cognitive enhancer, increases synapses in the hippocampal CA3 region of aged rats

2000 ◽  
Vol 82 ◽  
pp. 238
Author(s):  
Akira Moriguchi ◽  
Kazuo Nakano ◽  
Kouichi Sano ◽  
Kosei Noda ◽  
Nobuya Matsuoka ◽  
...  
Keyword(s):  
Aged Rats ◽  
Cognitive Enhancer ◽  
Hippocampal Ca3 ◽  
Ca3 Region

β1-and β2-adrenoceptors in hippocampal CA3 region are required for long-term memory consolidation in rats

2015 ◽  
Vol 1627 ◽  
pp. 109-118 ◽  
Author(s):  
Jian Zheng ◽  
Fei Luo ◽  
Nan-nan Guo ◽  
Zong-yue Cheng ◽  
Bao-ming Li
Keyword(s):  
Memory Consolidation ◽  
Long Term Memory ◽  
Term Memory ◽  
Hippocampal Ca3 ◽  
Ca3 Region
Sign in / Sign up

Export Citation Format

Share Document