An often-overlooked element of the fresh new anatomy of your echo neuron system is the current presence of backwards connectivity regarding PM to help you STS, hence appear to have an internet inhibitory dictate [55,56]. Of a Hebbian viewpoint, of these contacts the situation is a bit additional, while the PM neurons in fact flame prior to the STS neurons, because the Hebbian reading demands, albeit 2 hundred ms rather than the 40 ms earlier in the day that will be optimal to possess Hebbian understanding. And this, for these inhibitory viewpoints connections, inhibitory projections regarding PM neurons security a particular phase of one’s action is going to be reinforced which have STS representations of the same step hence occurring before ( shape step 3 c).
The vision and you may voice out of an activity trigger interest from inside the STS neurons
Once we consider both the forward and backwards information flow, the mirror neuron system no longer seems a simple associative system 
in which the sight of a given action triggers the motor representation of that action. This leads to a pattern of predictive activation of PM neurons encoding the action that occurs 200 ms after what the STS neurons represent, with their respective activation levels representing the likelihood of their occurrence based on past sensorimotor contingencies. However, the system would not stop at that point. This prediction in PM neurons is sent backwards as an inhibitory signal to STS neurons. Because the feedback should be onto neurons representing the previous and current actions represented in PM, it should have two consequences. It would terminate the sensory representation of past actions, which could contribute to what is often termed backward masking in the visual literature . Second, by cancelling representations associated with xstep step one, x2 and x3 with their respective probabilities, it will essentially inhibit those STS neurons that represent the expected sensory consequences of the action that the PM neurons predict to occur. At a more conceptual level, it would inhibit the hypothesis that PM neurons entertain about the next action to be perceived. As the brain then sees and hears what action actually comes next, if this input matches the hypothesis, the sensory consequences of that action would be optimally inhibited, and little information would be sent from STS > PM. 3 would then trigger activation of those actions that normally follow action x3 during execution, actively generating a whole stream of action representations of PM neurons without the need for any further sensory drive, and these further predictions would keep inhibiting future STS input. If action x2 were to follow action A, the inhibition would be weaker and more of the sensory representation of x2 would leak through to PM. This would represent a ‘prediction error’, which will change the pattern of PM activity to better match the input, away from the prior expectations. If action x1 were to follow action A, no cancellation would be in place in the STS, and the strongest activity would be sent from STS > PM, rerouting PM activity onto a stream of actions that normally follows x1, rather than x3, as initially hypothesized.
Because PM neurons (and the posterior parietal neurons ) was structured doing his thing stores inside the premotor cortex, the fresh new icon off action x
At that temporal quality, throughout the step observation/paying attention, brand new pattern of pastime across the nodes in PM has stopped being a straightforward reflect out of what will happen into the STS, but a positively predicted possibilities shipping for what the fresh new observer is to perceive the fresh observed private doing 2nd. Because of the virtue away from Hebbian studying, the complete STS-PM cycle will get a working program one really works predictive programming. In the event that noticed action spread totally affirmed, passion on PM carry out in fact end up being generated utilizing the sequences out of typical system handle unlike by artwork type in.
