Figure 1

Cartoon showing lateral entry of activity from a cue stimulus inducing a) formation of semblances, and b) activation of neurons that otherwise would not have activated in the absence of prior associated learning. When activity from two different sensory receptors passes through their synapses A-B and C-D (in square box) simultaneously, during associative learning, a functional LINK is formed between the postsynapses B and D. After learning, the cue stimulus reaching postsynpse B re-activates (gates through) the inter-postsynaptic functional LINK between the postsynapses B and D and activates postsynapse D, evoking the cellular hallucination (semblance) at the postsynapse D that it is being activated by an action potential reaching its presynapse C, one of the axonal terminals of the neuron Z. The sensory meaning of this hallucination is that the postsynapse D is receiving activity from the neuron Z, which is normally activated by a set of neurons {Y} at its lower neuronal orders that synapse to it. The set of neurons {Y} is normally activated by the activation of the set of neurons {X}, which in turn are activated by the set of neurons {W}. Continuing this extrapolation towards the sensory receptor level identifies a set of sensory receptors {SR}. Subsets of {SR} namely {sr1}, {sr2}, and {sr3} are capable of independently activating the neuron Z. The hypothetical packets of sensory stimuli capable of activating {sr1}, {sr2}, and {sr3} are called semblions 1, 2 and 3 respectively. Activation of the postsynapse D contribute additional EPSP to the neuron N1 that otherwise receives only sub-threshold activation, leading to its activation. Vertical vector for the oscillating neuronal activities is contributed by normal synaptic transmission and horizontal vector by lateral spread of activity through inter-postsynaptic LINKs and recurrent collaterals (shown from neuron N1 to N2). Cross-section through large number of postsynapses is shown within a dotted circle which includes an islet of 6 functionally LINKed postsynapses (B-D-F-H-J-L) along with two additional islets (modified from [23].