An intracellular Ca2+ subsystem as a biologically plausible source of intrinsic conditional bistability in a network model of working memory.
We have developed a firing rate network model for working memory that combines Mexican-hat-like synaptic coupling with intrinsic or cellular dynamics that are conditionally bistable. While our approach is in the spirit of Camperi and Wang (1998) we include a specific and plausible mechanism for the cellular bistability. Modulatory neurotransmitters are known to activate second messenger signaling systems, and our model includes an intracellular Ca(2+) handling subsystem whose dynamics depend upon the level of the second messenger inositol 1,4,5 trisphosphate (IP3). This Ca(2+) subsystem endows individual units with conditional intrinsic bistability for a range of IP3. The full "hybrid" network sustains IP3-dependent persistent ("bump") activity in response to a brief transient stimulus. The bump response in our hybrid model, like that of Camperi-Wang, is resistant to noise-- its position does not drift with time.
Fall
Christopher P
CP
Department of Anatomy and Cell Biology, University of Illinois at Chicago Medical Center, 808 South Wood St., Room 578, M/C 512, 60612. fall@uic.edu
Rinzel
John
J
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008570:Memory, Short-Term / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D016571:Neural Networks, Computer; D017711:Nonlinear Dynamics; D015398:Signal Transduction / Q000502:physiology
D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium