The role of short-term depression in sustained neural activity in the prefrontal cortex: a simulation study.
Recent experimental researches have suggested that sustained neural activity in the prefrontal cortex is a process of memory retention in decision making. Previous theoretical studies indicate that a balance between recurrent excitation and feedback inhibition is important for sustaining the activity. To investigate a plausible balancing mechanism, we simulated a biophysically realistic network model. Our model shows that short-term depression (STD) enables the network to sustain its activity despite the presence of long-term inhibition by GABA(B) receptors and that the sustained firing rates have a bell-shaped dependence on the degree of STD. By analyzing the neural network dynamics, we show that the bell-shaped dependence on STD is formed by destabilizing the balance with either excessive or insufficient STD. We also show that the optimal degree of STD has a linear relationship with the neural network size. These results suggest that STD provides a balancing mechanism and controls levels of sustained activities of various size networks.
Igarashi
Yasunobu
Y
Graduate School of Information Science, Nara Institute of Science and Technology 8916-5, Takayama, Ikoma, Nara, Japan. yasu-i@is.naist.jp
Sakumura
Yuichi
Y
Ishii
Shin
S
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D003198:Computer Simulation; D008959:Models, Neurological; D009415:Nerve Net / Q000166:cytology / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology*; D017397:Prefrontal Cortex / Q000166:cytology* / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D018091:Receptors, AMPA / Q000502:physiology; D018080:Receptors, GABA-B / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013997:Time Factors
D018091:Receptors, AMPA; D018080:Receptors, GABA-B; D016194:Receptors, N-Methyl-D-Aspartate