A biological blueprint for the axons of superficial layer pyramidal cells in cat primary visual cortex

In the cerebral cortex, the interaction of excitatory and inhibitory synaptic inputs shapes the responses of neurons to sensory stimuli, stabilizes network dynamics1 and improves the efficiency and robustness of the neural code2–4. Excitatory neurons receive inhibitory inputs that track excitation5–8. However, how this co-tuning of excitation and inhibition is achieved by cortical circuits is unclear, since inhibitory interneurons are thought to pool the inputs of nearby excitatory cells and provide them with non-specific inhibition proportional to the activity of the local network9–13. Here we show that although parvalbumin-expressing (PV) inhibitory cells in mouse primary visual cortex make connections with the majority of nearby pyramidal cells, the strength of their synaptic connections is structured according to the similarity of the cells’ responses. Individual PV cells strongly inhibit those pyramidal cells that provide them with strong excitation and share their visual selectivity. This fine-tuning of synaptic weights supports co-tuning of inhibitory and excitatory inputs onto individual pyramidal cells despite dense connectivity between inhibitory and excitatory neurons. Our results indicate that individual PV cells are preferentially integrated into subnetworks of inter-connected, co-tuned pyramidal cells, stabilising their recurrent dynamics. Conversely, weak but dense inhibitory connectivity between subnetworks is sufficient to support competition between them, de-correlating their output. We suggest that the history and structure of correlated firing adjusts the weights of both inhibitory and excitatory connections, supporting stable amplification and selective recruitment of cortical subnetworks.

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1727 Roles of horizontal connection in superficial layer of the kitten primary visual cortex studied in in vivo and in vitro preparation

Neuroscience Research ◽

10.1016/0168-0102(96)89123-1 ◽

1996 ◽

Vol 25 ◽

pp. S200

Author(s):

Yumiko Yoshimura ◽

Hiromichi Sato ◽

Kazuyuki Imamura ◽

Yasuyoshi Watanabe

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Superficial Layer ◽

Horizontal Connection

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Expression of GABAAReceptor Subunit mRNAs by Layer V Pyramidal Cells of the Rat Primary Visual Cortex

European Journal of Neuroscience ◽

10.1111/j.1460-9568.1997.tb01435.x ◽

1997 ◽

Vol 9 (4) ◽

pp. 857-862 ◽

Cited By ~ 19

Author(s):

Diego Ruano ◽

David Perrais ◽

Jean Rosier ◽

Nicole Ropert

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Pyramidal Cells ◽

Layer V

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Opposing forms of adaptation in mouse visual cortex are controlled by distinct inhibitory microcircuits and gated by locomotion

10.1101/2020.01.16.909788 ◽

2020 ◽

Cited By ~ 1

Author(s):

Tristan G. Heintz ◽

Antonio J. Hinojosa ◽

Leon Lagnado

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Internal State ◽

Pyramidal Cells ◽

External World ◽

Neural Circuitry ◽

Cortical Processing ◽

Locomotor Behaviour ◽

Different Types ◽

Mouse Visual Cortex

SummaryCortical processing of sensory signals adjusts to changes in both the external world and the internal state of the animal. We investigated the neural circuitry by which these processes interact in the primary visual cortex of mice. An increase in contrast caused as many pyramidal cells (PCs) to sensitize as depress, reflecting the dynamics of adaptation in different types of interneuron (PV, SST and VIP). Optogenetic manipulations demonstrate that the net effect within PCs reflects the balance of PV inputs, driving depression, and a subset of SST interneurons, driving sensitization. Locomotor behaviour increased the gain of PC responses by disinhibition through both the VIP->SST and SST->PV pathways, thereby maintaining the balance between opposing forms of plasticity. These experiments reveal how inhibitory microcircuits interact to purpose different subsets of PCs for the signalling of increases or decreases in contrast while also allowing for behavioural control of gain across the population.

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Axonal distribution and functional topography of layer 6 pyramidal cells in the primary visual cortex of the cat (Area 18).

Frontiers in Systems Neuroscience ◽

10.3389/conf.neuro.01.2009.04.201 ◽

2009 ◽

Vol 3 ◽

Author(s):

Zoltan Kisvarday

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Pyramidal Cells ◽

Area 18 ◽

Functional Topography

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Multiple gamma rhythms carry distinct spatial frequency information in primary visual cortex

PLoS Biology ◽

10.1371/journal.pbio.3001466 ◽

2021 ◽

Vol 19 (12) ◽

pp. e3001466

Author(s):

Chuanliang Han ◽

Tian Wang ◽

Yi Yang ◽

Yujie Wu ◽

Yang Li ◽

...

Keyword(s):

Visual Cortex ◽

Spatial Frequency ◽

Primary Visual Cortex ◽

Spike Activity ◽

Brain Regions ◽

Superficial Layer ◽

Cortical Level ◽

High Gamma ◽

Gamma Rhythms ◽

Surprising Finding

Gamma rhythms in many brain regions, including the primary visual cortex (V1), are thought to play a role in information processing. Here, we report a surprising finding of 3 narrowband gamma rhythms in V1 that processed distinct spatial frequency (SF) signals and had different neural origins. The low gamma (LG; 25 to 40 Hz) rhythm was generated at the V1 superficial layer and preferred a higher SF compared with spike activity, whereas both the medium gamma (MG; 40 to 65 Hz), generated at the cortical level, and the high gamma HG; (65 to 85 Hz), originated precortically, preferred lower SF information. Furthermore, compared with the rates of spike activity, the powers of the 3 gammas had better performance in discriminating the edge and surface of simple objects. These findings suggest that gamma rhythms reflect the neural dynamics of neural circuitries that process different SF information in the visual system, which may be crucial for multiplexing SF information and synchronizing different features of an object.

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