scholarly journals Comparing basal dendrite branches in human and mouse hippocampal CA1 pyramidal neurons with Bayesian networks

2020 ◽  
Author(s):  
Bojan Mihaljević ◽  
Pedro Larrañaga ◽  
Ruth Benavides-Piccione ◽  
Javier DeFelipe ◽  
Concha Bielza
Keyword(s):  
Bayesian Networks ◽  
Pyramidal Neurons ◽  
Graphical Representation ◽  
Data Set ◽  
Ca1 Region ◽  
Basal Dendrites ◽  
Hippocampal Ca1 ◽  
Dendritic Branches ◽  
Branch Type ◽  
Human And Mouse

ABSTRACTPyramidal neurons are the most common cell type in the cerebral cortex. Understanding how they differ between species is a key challenge in neuroscience. A recent study provided a unique set of human and mouse pyramidal neurons of the CA1 region of the hippocampus, and used it to compare the morphology of apical and basal dendritic branches of the two species. The study found inter-species differences in the magnitude of the morphometrics and similarities regarding their variation with respect to morphological determinants such as branch type and branch order. We use the same data set to perform additional comparisons of basal dendrites. In order to isolate the heterogeneity due to intrinsic differences between species from the heterogeneity due to differences in morphological determinants, we fit multivariate models over the morphometrics and the determinants. In particular, we use conditional linear Gaussian Bayesian networks, which provide a concise graphical representation of the independencies and correlations among the variables. We also extend the previous study by considering additional morphometrics and by formally testing test whether a morphometric increases or decreases with the distance from the soma. This study introduces a multivariate methodology for inter-species comparison of morphology.

scholarly journals Comparing basal dendrite branches in human and mouse hippocampal CA1 pyramidal neurons with Bayesian networks

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bojan Mihaljević ◽  
Pedro Larrañaga ◽  
Ruth Benavides-Piccione ◽  
Javier DeFelipe ◽  
Concha Bielza
Keyword(s):  
Bayesian Networks ◽  
Pyramidal Neurons ◽  
Graphical Representation ◽  
Data Set ◽  
Ca1 Region ◽  
Basal Dendrites ◽  
Hippocampal Ca1 ◽  
Dendritic Branches ◽  
Branch Type ◽  
Human And Mouse

Abstract Pyramidal neurons are the most common cell type in the cerebral cortex. Understanding how they differ between species is a key challenge in neuroscience. A recent study provided a unique set of human and mouse pyramidal neurons of the CA1 region of the hippocampus, and used it to compare the morphology of apical and basal dendritic branches of the two species. The study found inter-species differences in the magnitude of the morphometrics and similarities regarding their variation with respect to morphological determinants such as branch type and branch order. We use the same data set to perform additional comparisons of basal dendrites. In order to isolate the heterogeneity due to intrinsic differences between species from the heterogeneity due to differences in morphological determinants, we fit multivariate models over the morphometrics and the determinants. In particular, we use conditional linear Gaussian Bayesian networks, which provide a concise graphical representation of the independencies and correlations among the variables. We also extend the previous study by considering additional morphometrics and by formally testing whether a morphometric increases or decreases with the distance from the soma. This study introduces a multivariate methodology for inter-species comparison of morphology.

scholarly journals Comparing the electrophysiology and morphology of human and mouse layer 2/3 pyramidal neurons with Bayesian networks

2020 ◽  
Author(s):  
Bojan Mihaljević ◽  
Pedro Larrañaga ◽  
Concha Bielza
Keyword(s):  
Bayesian Networks ◽  
Probabilistic Reasoning ◽  
Pyramidal Neurons ◽  
Temporal Cortex ◽  
Input Resistance ◽  
Cell Types ◽  
Dendritic Arbor ◽  
Basal Dendrites ◽  
Morphological Variables ◽  
Human And Mouse

ABSTRACTPyramidal neurons are the most common neurons in the cerebral cortex. Understanding how they differ between species is a key challenge in neuroscience. We compared human temporal cortex and mouse visual cortex pyramidal neurons from the Allen Cell Types Database in terms of their electrophysiology and basal dendrites’ morphology. We found that, among other differences, human pyramidal neurons had a higher threshold voltage, a lower input resistance, and a larger basal dendritic arbor. We learned Gaussian Bayesian networks from the data in order to identify correlations and conditional independencies between the variables and compare them between the species. We found strong correlations between electrophysiological and morphological variables in both species. One result is that, in human cells, dendritic arbor width had the strongest effect on input resistance after accounting for the remaining variables. Electrophysiological variables were correlated, in both species, even with morphological variables that are not directly related to dendritic arbor size or diameter, such as mean bifurcation angle and mean branch tortuosity. Contrary to previous results, cortical depth was correlated with both electrophysiological and morphological variables, and its effect on electrophysiological could not be explained in terms of the morphological variables. Overall, the correlations among the variables differed strikingly between human and mouse neurons. Besides identifying correlations and conditional independencies, the learned Bayesian networks might be useful for probabilistic reasoning regarding the morphology and electrophysiology of pyramidal neurons.

scholarly journals Differential Structure of Hippocampal CA1 Pyramidal Neurons in the Human and Mouse

2019 ◽  
Author(s):  
Ruth Benavides-Piccione ◽  
Mamen Regalado-Reyes ◽  
Isabel Fernaud-Espinosa ◽  
Asta Kastanauskaite ◽  
Silvia Tapia-González ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Homologous Region ◽  
Ca1 Pyramidal Cells ◽  
Ca1 Region ◽  
Hippocampal Ca1 ◽  
Structural Differences ◽  
Species Specific ◽  
Human And Mouse ◽  
Shed Light

Abstract Pyramidal neurons are the most common cell type and are considered the main output neuron in most mammalian forebrain structures. In terms of function, differences in the structure of the dendrites of these neurons appear to be crucial in determining how neurons integrate information. To further shed light on the structure of the human pyramidal neurons we investigated the geometry of pyramidal cells in the human and mouse CA1 region—one of the most evolutionary conserved archicortical regions, which is critically involved in the formation, consolidation, and retrieval of memory. We aimed to assess to what extent neurons corresponding to a homologous region in different species have parallel morphologies. Over 100 intracellularly injected and 3D-reconstructed cells across both species revealed that dendritic and axonal morphologies of human cells are not only larger but also have structural differences, when compared to mouse. The results show that human CA1 pyramidal cells are not a stretched version of mouse CA1 cells. These results indicate that there are some morphological parameters of the pyramidal cells that are conserved, whereas others are species-specific.

Kinetic properties of T-type Ca2+ currents in isolated rat hippocampal CA1 pyramidal neurons

1991 ◽  
Vol 65 (1) ◽  
pp. 148-155 ◽  
Author(s):  
K. Takahashi ◽  
S. Ueno ◽  
N. Akaike
Keyword(s):  
Pyramidal Neurons ◽  
External Solution ◽  
Kinetic Properties ◽  
Temperature Sensitive ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1 ◽  
Current Voltage ◽  
Steady State Inactivation ◽  
The Individual

1. T-type Ca2+ channels producing a transient inward current were studied in pyramidal neurons acutely isolated from the ventral portion of rat hippocampal CA1 region. Membrane currents were recorded by the suction-pipette technique, which allows for internal perfusion under a single-electrode voltage clamp. 2. In all cells superfused with external solution containing 10 mM Ca2+, the T-type Ca2+ current was evoked by step depolarization to potentials more positive than -60 mV from a holding potential of -100 mV and reached a peak in the current-voltage relationship around -30 mV at 20–22 degrees C. 3. Activation and inactivation processes of T-type Ca2+ current were highly potential dependent, and the latter was fitted by a single exponential function. 4. Steady-state inactivation of T-type Ca2+ current could be fitted by a Boltzmann's equation with a slope factor of 6.0 and a half-inactivated voltage of -79 mV. 5. Recovery from inactivation of T-type Ca2+ current was not a single exponent. The major component of recovery (60-90% of total) was voltage sensitive with a time constant of 215 ms at -100 mV. 6. Amplitude of the T-type Ca2+ current depended on the external Ca2+ concentration. The ratio of peak amplitude in the individual current-voltage relationships of Ca2+, Ba2+, and Sr2+ currents passing through T-type Ca2+ channel was 1.0:0.85:1.32. The current kinetics were much the same. 7. All kinetic properties, including activation and inactivation, as well as the amplitude of T-type Ca2+ current, were temperature sensitive with Q10 (temperature coefficient) values of 1.7–;2.5.(ABSTRACT TRUNCATED AT 250 WORDS)

Serotonin Modulates Spike Backpropagation and Associated [Ca2+]i Changes in the Apical Dendrites of Hippocampal CA1 Pyramidal Neurons

1999 ◽  
Vol 81 (1) ◽  
pp. 216-224 ◽  
Author(s):  
Vladislav M. Sandler ◽  
William N. Ross
Keyword(s):  
Action Potentials ◽  
Pyramidal Neurons ◽  
Peak Potential ◽  
Fura 2 ◽  
Ca1 Pyramidal Neurons ◽  
Ca1 Region ◽  
Artificial Cerebrospinal Fluid ◽  
Hippocampal Ca1 ◽  
Conductance Increase ◽  
Apical Dendrites

Sandler, Vladislav M. and William N. Ross. Serotonin modulates spike backpropagation and associated [Ca2+]i changes in the apical dendrites of hippocampal CA1 pyramidal neurons. J. Neurophysiol. 81: 216–224, 1999. The effect of serotonin (5-HT) on somatic and dendritic properties was analyzed in pyramidal neurons from the CA1 region in slices from the rat hippocampus. Bath-applied 5-HT (10 μM) hyperpolarized the soma and apical dendrites and caused a conductance increase at both locations. In the dendrites (200–300 μm from the soma) trains of antidromically activated, backpropagating action potentials had lower peak potentials in 5-HT than in normal artificial cerebrospinal fluid. Spike amplitudes were about the same in the two solutions. Similar results were found when the action potentials were evoked synaptically with stimulation in the stratum oriens. In the soma, spike amplitudes increased in 5-HT, with only a small decrease in the peak potential. Calcium concentration measurements, made with bis-fura-2 injected through patch electrodes, showed that the amplitude of the [Ca2+]i changes was reduced at all locations in 5-HT. The reduction of the [Ca2+]i change in the soma was confirmed in slices where cells were loaded with fura-2-AM. The reduction at the soma in 5-HT, where the spike amplitude increased, suggests that the reduction is due primarily to direct modulation of Ca2+ channels. In the dendrites, the reduction is due to a combination of this channel modulation and the lowering of the peak potential of the action potentials.

scholarly journals Comparing the Electrophysiology and Morphology of Human and Mouse Layer 2/3 Pyramidal Neurons With Bayesian Networks

2021 ◽  
Vol 15 ◽  
Author(s):  
Bojan Mihaljević ◽  
Pedro Larrañaga ◽  
Concha Bielza
Keyword(s):  
Bayesian Networks ◽  
Probabilistic Reasoning ◽  
Pyramidal Neurons ◽  
Temporal Cortex ◽  
Input Resistance ◽  
Cell Types ◽  
Dendritic Morphology ◽  
Morphological Variables ◽  
Mouse Visual Cortex ◽  
Human And Mouse

Pyramidal neurons are the most common neurons in the cerebral cortex. Understanding how they differ between species is a key challenge in neuroscience. We compared human temporal cortex and mouse visual cortex pyramidal neurons from the Allen Cell Types Database in terms of their electrophysiology and dendritic morphology. We found that, among other differences, human pyramidal neurons had a higher action potential threshold voltage, a lower input resistance, and larger dendritic arbors. We learned Gaussian Bayesian networks from the data in order to identify correlations and conditional independencies between the variables and compare them between the species. We found strong correlations between electrophysiological and morphological variables in both species. In human cells, electrophysiological variables were correlated even with morphological variables that are not directly related to dendritic arbor size or diameter, such as mean bifurcation angle and mean branch tortuosity. Cortical depth was correlated with both electrophysiological and morphological variables in both species, and its effect on electrophysiology could not be explained in terms of the morphological variables. For some variables, the effect of cortical depth was opposite in the two species. Overall, the correlations among the variables differed strikingly between human and mouse neurons. Besides identifying correlations and conditional independencies, the learned Bayesian networks might be useful for probabilistic reasoning regarding the morphology and electrophysiology of pyramidal neurons.

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