Abstract
Synaptic plasticity is considered to play a crucial role in the experience-dependent self-organization of local cortical networks. In the absence of sensory stimuli, cerebral cortex exhibits spontaneous membrane potential transitions between an UP and a DOWN state. To reveal how cortical networks develop spontaneous activity, or conversely, how spontaneous activity structures cortical networks, we analyze the self-organization of a recurrent network model of excitatory and inhibitory neurons, which is realistic enough to replicate UP–DOWN states, with spike-timing-dependent plasticity (STDP). The individual neurons in the self-organized network exhibit a variety of temporal patterns in the two-state transitions. In addition, the model develops a feed-forward network-like structure that produces a diverse repertoire of precise sequences of the UP state. Our model shows that the self-organized activity well resembles the spontaneous activity of cortical networks if STDP is accompanied by the pruning of weak synapses. These results suggest that the two-state membrane potential transitions play an active role in structuring local cortical circuits.
Highlights
Cortical networks show complex dynamics of intrinsic activity when sensory inputs are absent
The cerebral cortex occupies a large portion of the brain in primates and humans, so the organization of local cortical networks is essential for the emergence of higher cognitive functions
We investigate the neuronal wiring and activity self-organizing with synaptic plasticity in a model of local cortical networks
Summary
Cortical networks show complex dynamics of intrinsic activity when sensory inputs are absent. Whether this spontaneous activity is a mere idling state of the brain or, rather, an internal state that actively engages in brain functions remains unclear. Recent experimental studies have revealed an important characteristic of the intrinsic dynamics of cortical neurons. In vivo and in vitro cortical pyramidal neurons exhibit spontaneous transitions of the membrane potentials between a depolarizing UP state and a resting DOWN state [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. Since blockade of glutermatergic synaptic transmissions eliminated the membrane potential transitions, recurrent synaptic input is considered to be crucial for these transitions
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