Local Order within Global Disorder: Synaptic Architecture of Visual Space

Scholl, Benjamin; Wilson, Dana E.; Fitzpatrick, David

doi:10.1016/j.neuron.2017.10.017

Cited by 112 publications

(157 citation statements)

References 48 publications

(94 reference statements)

Supporting

Mentioning

145

Contrasting

Order By: Relevance

“…4D, right and F). Orientation clustering has recently been reported in layer 2/3 of the adult ferret visual cortex recorded in vivo (5,7) . In addition, the correlations between pairs of synapses trained with retinal wave input (but not white noise) in our simulations decay with distance at the same rate as measured from spontaneous activity in experiments ( Fig.…”

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 82%

“…4A). Since activation of a synapse depends on the appropriate stimulation of its associated receptive field by retinal waves, synapses whose receptive fields have nearby centers in visual space (as is the case in the ferret visual cortex (7) ) and a small difference in orientation receive correlated input (Fig. 4B).…”

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 99%

“…Next, we investigated the functional implications of correlation-and distance-dependent plasticity in our minimal model on synaptic organization with retinal wave input. We distributed synaptic inputs with randomly oriented receptive fields and centers distributed in visual space as measured experimentally (7) on a non-branching, linear dendrite and stimulated them with action potentials after passing retinal waves through an LN model ( Fig. 4D, left).…”

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 99%

“…4C). Upon the removal of a synapse, a new synapse was placed at a random position on the dendritic branch having a receptive field with random orientation and visual space location sampled from the experimentally characterized distribution (7) (see Methods).…”

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 99%

“…Interestingly, some in vivo studies have reported lack of fine-scale synaptic organization (12)(13)(14)(15)(16) , while others reported clustering for different stimulus features in different species. For example, dendritic branches in the ferret visual cortex exhibit local clustering of orientation selectivity but do not exhibit global organization of inputs according to spatial location and receptive field properties (5,7) . In contrast, synaptic inputs in mouse visual cortex do not cluster locally by orientation, but only by receptive field overlap, and exhibit a global retinotopic organization along the proximal-distal axis (6) .…”

mentioning

confidence: 99%

See 4 more Smart Citations

A unifying framework for synaptic organization on cortical dendrites

Kirchner

Gjorgjieva

2019

Preprint

View full text Add to dashboard Cite

Dendritic synaptic inputs are organized into functional clusters with remarkable subcellular precision at the micron level. This organization emerges during early postnatal development through patterned spontaneous activity and manifests both locally where nearby synapses are significantly correlated, and globally with distance to the soma. We propose a biophysically motivated synaptic plasticity model to dissect the mechanistic origins of this organization during development, and elucidate synaptic clustering of different stimulus features in the adult. Our model captures local clustering of orientation in ferret vs. receptive field overlap in mouse visual cortex based on the cortical magnification of visual space. Including a back-propagating action potential explains branch clustering heterogeneity in the ferret, and produces a global retinotopy gradient from soma to dendrite in the mouse. Therefore, our framework suggests that sub-cellular precision in connectivity can already be established in development, and unifies different aspects of synaptic organization across species and scales.Neurons in the developing brain are already precisely connected before sensory organs mature. It is widely accepted that spontaneous activity refines circuit connectivity to mature levels at the scale of single neurons and networks. Recent studies have revealed that spontaneous activity can also establish fine-scale organization of individual synapses within the dendritic arborizations of single neurons (1,2) . One striking example of this organization is functional synaptic clustering: synapses onto dendrites of pyramidal neurons that receive correlated input or encode a common sensory feature are spatially grouped. Synaptic clustering has been observed across brain regions, developmental ages and diverse species from rodent to primate (1-10) and has multiple functional benefits; it compartmentalizes the dendrites of single neurons, enables supra-linear integration of inputs and shapes memory

show abstract

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 82%

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 99%

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 99%

Section: Retinal Wave Input and Synaptic Turnover Drive Synaptic Oriementioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

A unifying framework for synaptic organization on cortical dendrites

Kirchner

Gjorgjieva

2019

Preprint

View full text Add to dashboard Cite

show abstract

Astrocyte coverage of excitatory synapses correlates to measures of synapse structure and function in ferret primary visual cortex

Thomas,

Ryan,

McNabb

et al. 2024

Glia

View full text Add to dashboard Cite

Most excitatory synapses in the mammalian brain are contacted or ensheathed by astrocyte processes, forming tripartite synapses. Astrocytes are thought to be critical regulators of the structural and functional dynamics of synapses. While the degree of synaptic coverage by astrocytes is known to vary across brain regions and animal species, the reason for and implications of this variability remains unknown. Further, how astrocyte coverage of synapses relates to in vivo functional properties of individual synapses has not been investigated. Here, we characterized astrocyte coverage of synapses of pyramidal neurons in the ferret visual cortex and, using correlative light and electron microscopy, examined their relationship to synaptic strength and sensory‐evoked Ca2+ activity. Nearly, all synapses were contacted by astrocytes, and most were contacted along the axon–spine interface. Structurally, we found that the degree of synaptic astrocyte coverage directly scaled with synapse size and postsynaptic density complexity. Functionally, we found that the amount of astrocyte coverage scaled with how selectively a synapse responds to a particular visual stimulus and, at least for the largest synapses, scaled with the reliability of visual stimuli to evoke postsynaptic Ca2+ events. Our study shows astrocyte coverage is highly correlated with structural metrics of synaptic strength of excitatory synapses in the visual cortex and demonstrates a previously unknown relationship between astrocyte coverage and reliable sensory activation.

show abstract