scholarly journals Acute stress facilitates trace eyeblink conditioning in C57BL/6 male mice and increases the excitability of their CA1 pyramidal neurons

2005 ◽  
Vol 12 (2) ◽  
pp. 138-143 ◽  
Author(s):  
C. Weiss
Keyword(s):  
Pyramidal Neurons ◽  
Acute Stress ◽  
Eyeblink Conditioning ◽  
Male Mice ◽  
Ca1 Pyramidal Neurons ◽  
Trace Eyeblink Conditioning

Watermaze Learning Enhances Excitability of CA1 Pyramidal Neurons

2003 ◽  
Vol 90 (4) ◽  
pp. 2171-2179 ◽  
Author(s):  
M. Matthew Oh ◽  
Amy G. Kuo ◽  
Wendy W. Wu ◽  
Evgeny A. Sametsky ◽  
John F. Disterhoft
Keyword(s):  
Pyramidal Neurons ◽  
Dorsal Hippocampus ◽  
Eyeblink Conditioning ◽  
Hippocampal Pyramidal Neurons ◽  
Ca1 Neurons ◽  
Ca1 Pyramidal Neurons ◽  
Platform Location ◽  
Dorsal Hippocampal ◽  
Hippocampal Ca1 ◽  
Trace Eyeblink Conditioning

The dorsal hippocampus is crucial for learning the hidden-platform location in the hippocampus-dependent, spatial watermaze task. We have previously demonstrated that the postburst afterhyperpolarization (AHP) of hippocampal pyramidal neurons is reduced after acquisition of the hippocampus-dependent, temporal trace eyeblink conditioning task. We report here that the AHP and one or more of its associated currents ( IAHP and/or s IAHP) are reduced in dorsal hippocampal CA1 pyramidal neurons from rats that learned the watermaze task as compared with neurons from control rats. This reduction was a learning-induced phenomenon as the AHP of CA1 neurons from rats that failed to learn the hidden-platform location was similar to that of neurons from control rats. We propose that reduction of the AHP in pyramidal neurons in regions crucial for learning is a cellular mechanism of learning that is conserved across species and tasks.

scholarly journals Sex-Dependent Effects of Chronic Microdrive Implantation on Acquisition of Trace Eyeblink Conditioning

2021 ◽  
Author(s):  
Amy P Rapp ◽  
Timothy J Hark ◽  
John M Power ◽  
M Matthew Oh ◽  
Jeffrey N Savas ◽  
...  
Keyword(s):  
Sex Differences ◽  
Associative Learning ◽  
Mapk Pathway ◽  
Eyeblink Conditioning ◽  
Sexually Dimorphic ◽  
Male Mice ◽  
Tandem Mass Tag ◽  
The Impact ◽  
Trace Eyeblink Conditioning

Neuroscience techniques, including in vivo recording, have allowed for a great expansion in knowledge; however, this technology may also affect the very phenomena researchers set out to investigate. Including both female and male mice in our associative learning experiments shed light on sex differences on the impact of chronic implantation of tetrodes on learning. While previous research showed intact female mice acquired trace eyeblink conditioning faster than male and ovariectomized females, implantation of chronic microdrive arrays showed sexually dimorphic effects on learning. Microdrive implanted male mice acquired the associative learning paradigm faster than both intact and ovariectomized females. These effects were not due to the weight of the drive alone, as there were no significant sex-differences in learning of animals that received dummy drive implants without tetrodes lowered into the brain. Tandem mass tag mass spectrometry and western blot analysis suggest that significant alterations in the MAPK pathway, acute inflammation, and brain derived neurotrophic factor may underlie these observed sex- and surgery-dependent effects on learning.

scholarly journals Increasing SK2 channel activity impairs associative learning

2012 ◽  
Vol 108 (3) ◽  
pp. 863-870 ◽  
Author(s):  
Bridget M. McKay ◽  
M. Matthew Oh ◽  
Roberto Galvez ◽  
Jeffrey Burgdorf ◽  
Roger A. Kroes ◽  
...  
Keyword(s):  
Associative Learning ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Dorsal Hippocampus ◽  
Eyeblink Conditioning ◽  
Excitatory Postsynaptic Potential ◽  
Sk Channels ◽  
Hippocampal Pyramidal Neurons ◽  
Trace Eyeblink Conditioning

Enhanced intrinsic neuronal excitability of hippocampal pyramidal neurons via reductions in the postburst afterhyperpolarization (AHP) has been hypothesized to be a biomarker of successful learning. This is supported by considerable evidence that pharmacologic enhancement of neuronal excitability facilitates learning. However, it has yet to be demonstrated that pharmacologic reduction of neuronal excitability restricted to the hippocampus can retard acquisition of a hippocampus-dependent task. Thus, the present study was designed to address this latter point using a small conductance potassium (SK) channel activator NS309 focally applied to the dorsal hippocampus. SK channels are important contributors to intrinsic excitability, as measured by the medium postburst AHP. NS309 increased the medium AHP and reduced excitatory postsynaptic potential width of CA1 neurons in vitro. In vivo, NS309 reduced the spontaneous firing rate of CA1 pyramidal neurons and impaired trace eyeblink conditioning in rats. Conversely, trace eyeblink conditioning reduced levels of SK2 channel mRNA and protein in the hippocampus. Therefore, the present findings indicate that modulation of SK channels is an important cellular mechanism for associative learning and further support postburst AHP reductions in hippocampal pyramidal neurons as a biomarker of successful learning.

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