After the network had been trained for 24 h using spike-timing-dependent plasticity (Bi and Poo 1998; Markram et al. 1997), it was tested with a series of input patterns.




Bi GQ, Poo MM (1998) 
Synaptic modifications in cultured hippocampal neurons: dependence on spike timing, synaptic strength, and postsynaptic cell type. 
J Neurosci 18(24):10464.10472
--------------------------------------------------------------------------------------------------




The brain is continuously active. This spontaneously emerging activity manifests itself on different scales ranging from spontaneous spiking of single cells (Abeles 1991), over finegrained
spatio-temporal patterns as revealed by optical imaging
(Arieli et al. 1996; Kenet et al. 2003; Tsodyks et al. 1999)
to large-scale brain rhythms (Ba，sar 1980; Berger 1929), and
coordinated fluctuations of local brainmetabolism (Fox et al.
2007). In many cases, responses to specific stimuli emerge
from this ongoing activity in the form of transient resets
(Frund et al. 2007b; Hanslmayr et al. 2007; Makeig et al.
2002).





A particular type of such transient responses is the early
gamma band response (Herrmann et al. 2004b; Karaka，s and
Ba，sar 1998; Tiitinen et al. 1993).



Herrmann CS, Munk MH, Engel AK (2004b) 
Cognitive functions of gamma-band activity: memory match and utilization.
Trends Cogn Sci 8(8):347.355 => done


Karaka，s S, Ba，sar E (1998) 
Early gamma response is sensory in origin: a conclusion based on cross-comparison of results from multiple experimental paradigms.
Int J Psychophysiol 31:13.31


Tiitinen H, Sinkkonen J, Reinikainen K, Alho K, Lavikainen J, Naatanen R (1993) 
Selective attention enhances the auditory 40-Hz transient response in humans. 
Nature 364:59.60












"The network consisted of 800 excitatory cells and 200 inhibitory cells."

"Each neuron in the network projected to a total of 100 randomly
chosen other neurons in the network (equal probability
for each neuron). Thus 10% of all possible connections were
realized. Neurons never projected to themselves, and inhibitory
cells only projected to excitatory cells."




"We simulated single neurons using a generalized quadratic integrate-and-fire neuron as proposed by Izhikevich (2003)."

Izhikevich EM (2003) Simple model of spiking neurons. IEEE Trans
Neural Netw 14(6):1569.1572 => done



"In an initial training phase, the network synapses were modified by spike-timing-dependent plasticity. Each spike that arrives from an excitatory presynaptic neuron at a postsynaptic neuron, might trigger a spike in the postsynaptic neuron. Therefore, the corresponding synapse is strengthened after each spike. In addition, each spike that arrives right after the postsynaptic neuron fired, weakens the respective synapse. Details of the implementation are reported by Izhikevich (2006).


Izhikevich EM (2006) Polychronization: computation with spikes.
Neural Comput 18:245.282




The first simulation experiment resembled theEEGexperiments by Busch et al. (2004) and Frund et al. (2008b).

Frund I, Schadow J, Busch NA, Naue N, Korner U, Herrmann CS (2008b) 
Anticipation of natural stimuli modulates EEG dynamics:
physiology and simulation. Cogn Neurodyn 2(2):89.100 => OK



The second simulation experiment resembled the EEG
experiments by Herrmann et al. (2004a) and Frund et al.
(2008a).


Frund I, Busch NA, Schadow J, Gruber T, Korner U, Herrmann
CS (2008a) 
Time pressure modulates electrophysiological correlates of early visual processing. 
PLoS One 3(2):e1675






not-yet after
3 Results