Original article Age-related dendritic and spinal alterations of pyramidal cells of the human visual cortex

Mavroudis, Ioannis; Manani, Marina George; Petrides, Foivos; Dados, Dimitrios; Ciobîcă, Alin; Pădurariu, Manuela; Petsoglou, Konstantina; Njau, Samuel; Costa, Vassiliki; Baloyannis, Stavros J.

doi:10.5114/fn.2015.52406

Cited by 9 publications

(11 citation statements)

References 60 publications

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“…Our findings demonstrate that total dendritic length of lateral nucleus projection neurons continuously increases across development from childhood into adulthood. Since this is the only study of dendritic development from youth to adulthood in human amygdala to date, we can only draw comparisons from other brain regions where neuronal growth trajectories have been mapped across human lifespan, including visual, prefrontal, occipital, temporal, and hippocampal cortices (Scheibel, Lindsay, Tomiyasu, & Scheibel, ; Buell & Coleman, ; Becker, Armstrong, Chan, & Wood, ; Huttenlocher, ; Jacobs, Driscoll, & Schall, ; Mavroudis et al, ). Although there are brain region and layer specific subtleties, in general, dendrite growth is extremely rapid during late gestation and early childhood in cortical regions (Becker et al, ; Huttenlocher, ).…”

Section: Discussionmentioning

confidence: 99%

“…This early cortical dendritic growth is followed by a slower expansion through childhood into a relatively stable state during adolescence and adulthood (Huttenlocher, 1990;Jacobs et al, 1997;Travis, Ford, & Jacobs, 2005). In elderly brains, many studies report age-related reduction in cortical dendritic length (Scheibel et al, 1975(Scheibel et al, , 1976Mavroudis et al, 2015); however, findings of increasing dendritic arborization in the hippocampus between the sixth and eighth decade of life have also been reported (Becker et al, 1984;Flood, Buell, Defiore, Horwitz, & Coleman, 1985). Therefore, our findings suggest that the protracted growth of the amygdala into adulthood, through in part a mechanism of continuous neuronal and dendritic growth, is a unique feature of this brain region and may reflect the importance of amygdala function in modulating adolescent social and emotional development.…”

Section: Typical Developmentmentioning

confidence: 99%

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Protracted dendritic growth in the typically developing human amygdala and increased spine density in young ASD brains

Weir

Bauman

Jacobs

et al. 2017

J of Comparative Neurology

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The amygdala is a medial temporal lobe structure implicated in social and emotional regulation. In typical development (TD), the amygdala continues to increase volumetrically throughout childhood and into adulthood, while other brain structures are stable or decreasing in volume. In autism spectrum disorder (ASD), the amygdala undergoes rapid early growth, making it volumetrically larger in children with ASD compared to TD children. Here we explore: (a) if dendritic arborization in the amygdala follows the pattern of protracted growth in TD and early overgrowth in ASD and (b), if spine density in the amygdala in ASD cases differs from TD from youth to adulthood. The amygdala from 32 postmortem human brains (7–46 years of age) were stained using a Golgi-Kopsch impregnation. Ten principal neurons per case were selected in the lateral nucleus and traced using Neurolucida software in their entirety. We found that both ASD and TD individuals show a similar pattern of increasing dendritic length with age well into adulthood. However, spine density is (a) greater in young ASD cases compared to age-matched TD controls (<18 years old) and (b) decreases in the amygdala as people with ASD age into adulthood, a phenomenon not found in TD. Therefore, by adulthood, there is no observable difference in spine density in the amygdala between ASD and TD age-matched adults (≥18 years old). Our findings highlight the unique growth trajectory of the amygdala and suggest that spine density may contribute to aberrant development and function of the amygdala in children with ASD.

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Section: Discussionmentioning

confidence: 99%

Section: Typical Developmentmentioning

confidence: 99%

Protracted dendritic growth in the typically developing human amygdala and increased spine density in young ASD brains

Weir

Bauman

Jacobs

et al. 2017

J of Comparative Neurology

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“…Changes in any of those cortical areas can affect visual perception, and abnormal visual experience, especially in childhood, often disrupts the maturation of visual cortical circuits causing poor vision. The role of the visual cortex in processing visual perception and plasticity has been well studied in animal models, 1 – 9 but there are few studies about the neurobiology of human visual cortex 10 – 19 and even fewer examine how it develops and changes across the life span. 20 – 24 Brain imaging studies are beginning to address structural and functional development of the human cortex, 25 but the lack of information about cellular and molecular mechanisms has slowed the translation of biologically inspired treatments for visual disorders.…”

Section: Introductionmentioning

confidence: 99%

The development of human visual cortex and clinical implications

Siu¹,

Murphy²

2018

100

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The primary visual cortex (V1) is the first cortical area that processes visual information. Normal development of V1 depends on binocular vision during the critical period, and age-related losses of vision are linked with neurobiological changes in V1. Animal studies have provided important details about the neurobiological mechanisms in V1 that support normal vision or are changed by visual diseases. There is very little information, however, about those neurobiological mechanisms in human V1. That lack of information has hampered the translation of biologically inspired treatments from preclinical models to effective clinical treatments. We have studied human V1 to characterize the expression of neurobiological mechanisms that regulate visual perception and neuroplasticity. We have identified five stages of development for human V1 that start in infancy and continue across the life span. Here, we describe these stages, compare them with visual and anatomical milestones, and discuss implications for translating treatments for visual disorders that depend on neuroplasticity of V1 function.

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“…Along with these cognitive changes, aging is also a major risk factor for dementia and neurodegenerative disorders [5]. There are a number of age-related structural changes that occur in the brain at various levels: synapses [6], dendrites [7], circuits [8], and gray-matter volume [9]. Furthermore, some dynamic properties associated with aging have been reported [10], however, the effect of dendritic pruning caused by aging on neuronal dynamics remains largely unknown.…”

Section: Introductionmentioning

confidence: 99%

Dynamical effects of dendritic pruning implicated in aging and neurodegeneration: Towards a measure of neuronal reserve

Kirch

Gollo

2020

Preprint

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Aging is a main risk factor for neurodegenerative disorders including Alzheimer's disease. It is often accompanied by reduced cognitive functions, gray-matter volume, and dendritic integrity. Although age-related brain structural changes have been observed across multiple scales, their functional implications remain largely unknown. Here we simulate the aging effects on neuronal morphology as dendritic pruning and characterize its dynamical implications. Utilizing a minimal computational modeling approach, we simulate the dynamics of detailed digitally reconstructed pyramidal neurons of humans obtained from the online repository Neuromorpho.org. We show that as aging progressively affects neuronal integrity, neuronal firing rate is reduced, which causes a reduction in energy consumption, energy efficiency, and dynamic range. Pruned neurons require less energy but their function is often impaired, which can explain the diminished ability to distinguish between similar experiences (pattern separation) in older people. Our measures indicate that the resilience of neuronal dynamics is neuron-specific, heterogeneous, and strongly affected by dendritic topology and the centrality of the soma. Based on the emergent neuronal dynamics, we propose to classify the effects of dendritic deterioration, and put forward that soma centrality measures neuronal reserve. Moreover, our findings suggest that increasing dendritic excitability could partially mitigate the dynamical effects of aging.

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Original article Age-related dendritic and spinal alterations of pyramidal cells of the human visual cortex

Abstract: A b s t r a c t

Cited by 9 publications

References 60 publications

Protracted dendritic growth in the typically developing human amygdala and increased spine density in young ASD brains

Protracted dendritic growth in the typically developing human amygdala and increased spine density in young ASD brains

The development of human visual cortex and clinical implications

Dynamical effects of dendritic pruning implicated in aging and neurodegeneration: Towards a measure of neuronal reserve

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