Fractal analysis of dendritic arborization patterns of pyramidal neurons in human basolateral amygdala

Introduction Cortical amygdaloid nucleus belongs to the corticomedial part of the amygdaloid complex. In this nucleus there are neurons that produce neuropetide Y. This peptide has important roles in sleeping, learning, memory, gastrointestinal regulation, anxiety, epilepsy, alcoholism and depression. Material and methods We investigated morphometric characteristics (numbers of primary dendrites, longer and shorter diameters of cell bodies and maximal radius of dendritic arborization) of NPY immunoreactive neurons of human cortical amygdaloid nucleus on 6 male adult human brains, aged 46 to 77 years, by immunohistochemical avidin-biotin technique. Results Our investigation has shown that in this nucleus there is a moderate number of NPY immunoreactive neurons. 67% of found neurons were nonpyramidal, while 33% were pyramidal. Among the nonpyramidal neurons the dominant groups were multipolar neurons (41% - of which 25% were multipolar irregular, and 16% multipolar oval). Among the pyramidal neurons the dominant groups were the neurons with triangular shape of cell body (21%). All found NPY immunoreactive neurons (pyramidal and nonpyramidal altogether) had intervals of values of numbers of primary dendrites 2 to 6, longer diameters of cell bodies 13 to 38 ?m, shorter diameters of cell bodies 9 to 20 ?m and maximal radius of dendritic arborization 50 to 340 ?m. More than a half of investigated neurons (57%) had 3 primary dendrites. Discussion and conclusion The other researchers did not find such percentage of pyramidal immunoreactive neurons in this amygdaloid nucleus. If we compare our results with the results of the ather researchers we can conclude that all pyramidal NPY immunoreactive neurons found in this human amygdaloid nucleus belong to the class I of neurons, and that all nonpyramidal NPY immunoreactive neurons belong to the class II of neurons described by other researchers. We suppose that all found pyramidal neurons were projectional.

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Reduced GluN1 in mouse dentate gyrus is associated with CA3 hyperactivity and psychosis-like behaviors

Molecular Psychiatry ◽

10.1038/s41380-018-0124-3 ◽

2018 ◽

Vol 25 (11) ◽

pp. 2832-2843 ◽

Cited By ~ 6

Author(s):

Amir Segev ◽

Masaya Yanagi ◽

Daniel Scott ◽

Sarah A. Southcott ◽

Jacob M. Lister ◽

...

Keyword(s):

Dentate Gyrus ◽

Basolateral Amygdala ◽

Pyramidal Neurons ◽

Mossy Fibers ◽

Model Systems ◽

Memory Processing ◽

Hippocampal Subfields ◽

Whole Cell Patch Clamp ◽

Hippocampal Activity

Abstract Recent findings from in vivo-imaging and human post-mortem tissue studies in schizophrenic psychosis (SzP), have demonstrated functional and molecular changes in hippocampal subfields that can be associated with hippocampal hyperexcitability. In this study, we used a subfield-specific GluN1 knockout mouse with a disease-like molecular perturbation expressed only in hippocampal dentate gyrus (DG) and assessed its association with hippocampal physiology and psychosis-like behaviors. First, we used whole-cell patch-clamp recordings to measure the physiological changes in hippocampal subfields and cFos immunohistochemistry to examine cellular excitability. DG-GluN1 KO mice show CA3 cellular hyperactivity, detected using two approaches: (1) increased excitatory glutamate transmission at mossy fibers (MF)-CA3 synapses, and (2) an increased number of cFos-activated pyramidal neurons in CA3, an outcome that appears to project downstream to CA1 and basolateral amygdala (BLA). Furthermore, we examined psychosis-like behaviors and pathological memory processing; these show an increase in fear conditioning (FC), a reduction in prepulse inhibition (PPI) in the KO animal, along with a deterioration in memory accuracy with Morris Water Maze (MWM) and reduced social memory (SM). Moreover, with DREADD vectors, we demonstrate a remarkably similar behavioral profile when we induce CA3 hyperactivity. These hippocampal subfield changes could provide the basis for the observed increase in human hippocampal activity in SzP, based on the shared DG-specific GluN1 reduction. With further characterization, these animal model systems may serve as targets to test psychosis mechanisms related to hippocampus and assess potential hippocampus-directed treatments.

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Basolateral Amygdala α1-Adrenergic Receptor Suppression Attenuates Stress-Induced Anxiety-Like Behavior and Spine Morphology Impairment on Hippocampal CA1 Pyramidal Neurons

Neurochemical Journal ◽

10.1134/s1819712420010079 ◽

2020 ◽

Vol 14 (1) ◽

pp. 77-89 ◽

Cited By ~ 1

Author(s):

Nasrin Faraji ◽

Abdolhossein Shiravi ◽

Zahra Bahari ◽

Hossein Shirvani ◽

Gholam Hossein Meftahi

Keyword(s):

Adrenergic Receptor ◽

Basolateral Amygdala ◽

Pyramidal Neurons ◽

Spine Morphology ◽

Ca1 Pyramidal Neurons ◽

Hippocampal Ca1

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Amygdala inputs drive feedforward inhibition in the medial prefrontal cortex

Journal of Neurophysiology ◽

10.1152/jn.00531.2012 ◽

2013 ◽

Vol 110 (1) ◽

pp. 221-229 ◽

Cited By ~ 47

Author(s):

Jonathan Dilgen ◽

Hugo A. Tejeda ◽

Patricio O'Donnell

Keyword(s):

Prefrontal Cortex ◽

Basolateral Amygdala ◽

Pyramidal Neurons ◽

Reversal Potential ◽

Intracellular Recordings ◽

Action Potential Firing ◽

Gaba A ◽

Potential Firing ◽

Feedforward Inhibition

Although interactions between the amygdala and prefrontal cortex (PFC) are critical for emotional guidance of behavior, the manner in which amygdala affects PFC function is not clear. Whereas basolateral amygdala (BLA) output neurons exhibit many characteristics associated with excitatory neurotransmission, BLA stimulation typically inhibits PFC cell firing. This apparent discrepancy could be explained if local PFC inhibitory interneurons were activated by BLA inputs. Here, we used in vivo juxtacellular and intracellular recordings in anesthetized rats to investigate whether BLA inputs evoke feedforward inhibition in the PFC. Juxtacellular recordings revealed that BLA stimulation evoked action potentials in PFC interneurons and silenced most pyramidal neurons. Intracellular recordings from PFC pyramidal neurons showed depolarizing postsynaptic potentials, with multiple components evoked by BLA stimulation. These responses exhibited a relatively negative reversal potential (Erev), suggesting the contribution of a chloride component. Intracellular administration or pressure ejection of the GABA-A antagonist picrotoxin resulted in action-potential firing during the BLA-evoked response, which had a more depolarized Erev. These results suggest that BLA stimulation engages a powerful inhibitory mechanism within the PFC mediated by local circuit interneurons.

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Reduced dendritic arborization and hyperexcitability of pyramidal neurons in a Scn1b-based model of Dravet syndrome

Brain ◽

10.1093/brain/awu077 ◽

2014 ◽

Vol 137 (6) ◽

pp. 1701-1715 ◽

Cited By ~ 25

Author(s):

Christopher A. Reid ◽

Bryan Leaw ◽

Kay L. Richards ◽

Robert Richardson ◽

Verena Wimmer ◽

...

Keyword(s):

Pyramidal Neurons ◽

Dendritic Arborization ◽

Dravet Syndrome

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Coincidence Detection in Pyramidal Neurons Is Tuned by Their Dendritic Branching Pattern

Journal of Neurophysiology ◽

10.1152/jn.00046.2003 ◽

2003 ◽

Vol 89 (6) ◽

pp. 3143-3154 ◽

Cited By ~ 171

Author(s):

Andreas T. Schaefer ◽

Matthew E. Larkum ◽

Bert Sakmann ◽

Arnd Roth

Keyword(s):

Pyramidal Neurons ◽

Experimental Studies ◽

Brain Slices ◽

Apical Dendrite ◽

Dendritic Arborization ◽

Coincidence Detection ◽

Membrane Properties ◽

Relative Reduction ◽

Close Proximity ◽

The Relationship

Neurons display a variety of complex dendritic morphologies even within the same class. We examined the relationship between dendritic arborization and the coupling between somatic and dendritic action potential (AP) initiation sites in layer 5 (L5) neocortical pyramidal neurons. Coupling was defined as the relative reduction in threshold for initiation of a dendritic calcium AP due to a coincident back-propagating AP. Simulations based on reconstructions of biocytin-filled cells showed that addition of oblique branches of the main apical dendrite in close proximity to the soma ( d < 140 μm) increases the coupling between the apical and axosomatic AP initiation zones, whereas incorporation of distal branches decreases coupling. Experimental studies on L5 pyramids in acute brain slices revealed a highly significant ( n = 28, r = 0.63, P < 0.0005) correlation: increasing the fraction of proximal oblique dendrites ( d < 140 μm), e.g., from 30 to 60% resulted on average in an increase of the coupling from approximately 35% to almost 60%. We conclude that variation in dendritic arborization may be a key determinant of variability in coupling (49 ± 17%; range 19–83%; n = 37) and is likely to outweigh the contribution made by variations in active membrane properties. Thus coincidence detection of inputs arriving from different cortical layers is strongly regulated by differences in dendritic arborization.

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GABAergic innervation of alpha type II calcium/calmodulin-dependent protein kinase immunoreactive pyramidal neurons in the rat basolateral amygdala

The Journal of Comparative Neurology ◽

10.1002/cne.10204 ◽

2002 ◽

Vol 446 (3) ◽

pp. 199-218 ◽

Cited By ~ 88

Author(s):

Alexander J. McDonald ◽

Jay F. Muller ◽

Franco Mascagni

Keyword(s):

Protein Kinase ◽

Basolateral Amygdala ◽

Pyramidal Neurons ◽

Type Ii ◽

Dependent Protein Kinase ◽

Calcium Calmodulin Dependent ◽

Gabaergic Innervation ◽

Dependent Protein ◽

Alpha Type

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Endocannabinoid- and mGluR5-Dependent Short-Term Synaptic Depression in an Isolated Neuron/Bouton Preparation From the Hippocampal CA1 Region

Journal of Neurophysiology ◽

10.1152/jn.90226.2008 ◽

2008 ◽

Vol 100 (2) ◽

pp. 1041-1052 ◽

Cited By ~ 21

Author(s):

Anton Sheinin ◽

Giuseppe Talani ◽

Margaret I. Davis ◽

David M. Lovinger

Keyword(s):

Hippocampal Neurons ◽

Basolateral Amygdala ◽

Pyramidal Neurons ◽

Metabotropic Glutamate Receptor ◽

Hippocampal Slices ◽

Neuronal Membrane ◽

Short Term ◽

Ca1 Region ◽

Hippocampal Ca1 Region ◽

Isolated Neuron

Endocannabinoids released from the postsynaptic neuronal membrane can activate presynaptic CB1 receptors and inhibit neurotransmitter release. In hippocampal slices, depolarization of the CA1 pyramidal neurons elicits an endocannabinoid-mediated inhibition of γ-aminobutyric acid release known as depolarization-induced suppression of inhibition (DSI). Using the highly reduced neuron/synaptic bouton preparation from the CA1 region of hippocampus, we have begun to examine endocannabinoid-dependent short-term depression (STD) of inhibitory synaptic transmission under well-controlled physiological and pharmacological conditions in an environment free of other cells. Application of the CB1 synthetic agonist WIN55212 -2 and endogenous cannabinoids 2-AG and anandamide produced a decrease in spontaneous inhibitory postsynaptic current (sIPSC) frequency and amplitude, indicating the presence of CB1 receptors at synapses in this preparation. Endocannabinoid-dependent STD is different from DSI found in hippocampal slices and the neuron/bouton preparation from basolateral amygdala (BLA) since depolarization alone was not sufficient to induce suppression of sIPSCs. However, concurrent application of the metabotropic glutamate receptor (mGluR) agonist ( RS)-3,5-dihydroxyphenylglycine (DHPG) and postsynaptic depolarization resulted in a transient (30–50 s) decrease in sIPSC frequency and amplitude. Application of DHPG alone had no effect on sIPSCs. The depolarization/DHPG-induced STD was blocked by the CB1 antagonist SR141716A and the mGluR5 antagonist MPEP and was sensitive to intracellular calcium concentration. Comparing the present findings with earlier work in hippocampal slices and BLA, it appears that endocannabinoid release is less robust in isolated hippocampal neurons.

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Conditional deletion of ROCK2 induces anxiety-like behaviors and alters dendritic spine density and morphology on CA1 pyramidal neurons

Molecular Brain ◽

10.1186/s13041-021-00878-4 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Audrey J. Weber ◽

Ashley B. Adamson ◽

Kelsey M. Greathouse ◽

Julia P. Andrade ◽

Cameron D. Freeman ◽

...

Keyword(s):

Dendritic Spine ◽

Basolateral Amygdala ◽

Pyramidal Neurons ◽

Pyramidal Cells ◽

Spine Density ◽

Control Of Gene Expression ◽

Spine Morphology ◽

Dendritic Spine Morphology ◽

Morphometry Analysis ◽

Apical Dendrites

AbstractRho-associated kinase isoform 2 (ROCK2) is an attractive drug target for several neurologic disorders. A critical barrier to ROCK2-based research and therapeutics is the lack of a mouse model that enables investigation of ROCK2 with spatial and temporal control of gene expression. To overcome this, we generated ROCK2fl/fl mice. Mice expressing Cre recombinase in forebrain excitatory neurons (CaMKII-Cre) were crossed with ROCK2fl/fl mice (Cre/ROCK2fl/fl), and the contribution of ROCK2 in behavior as well as dendritic spine morphology in the hippocampus, medial prefrontal cortex (mPFC), and basolateral amygdala (BLA) was examined. Cre/ROCK2fl/fl mice spent reduced time in the open arms of the elevated plus maze and increased time in the dark of the light–dark box test compared to littermate controls. These results indicated that Cre/ROCK2fl/fl mice exhibited anxiety-like behaviors. To examine dendritic spine morphology, individual pyramidal neurons in CA1 hippocampus, mPFC, and the BLA were targeted for iontophoretic microinjection of fluorescent dye, followed by high-resolution confocal microscopy and neuronal 3D reconstructions for morphometry analysis. In dorsal CA1, Cre/ROCK2fl/fl mice displayed significantly increased thin spine density on basal dendrites and reduced mean spine head volume across all spine types on apical dendrites. In ventral CA1, Cre/ROCK2fl/fl mice exhibited significantly increased spine length on apical dendrites. Spine density and morphology were comparable in the mPFC and BLA between both genotypes. These findings suggest that neuronal ROCK2 mediates spine density and morphology in a compartmentalized manner among CA1 pyramidal cells, and that in the absence of ROCK2 these mechanisms may contribute to anxiety-like behaviors.

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