From my understanding most synapses were more typically like an usigned scalar weight, and the sign component comes from the action potential itself—which can be depolarizing or hyper-polarizing.
A hyperpolarization has a negative sign—it lowers the membrane potential voltage, a depolarization has a positive sign—raising the membrane potential voltage.
From what I remember neurons tend to specialize in one or the other (+polarization or -polarization based on their bias level), but some synaptic interactions may be able to reverse the sign as well (change an incoming + polarization into a -polarization, or vice versa). However, I’m less sure about how common that is.
So perhaps I do not understand what you mean when you talk about a “negative action potential”
From my (admittedly rusty) neurobiology, synapses increase or decrease the likelihood of the next neuron reaching action potential and firing.
If the first neuron has a “positive” action potential and a depolarizing synapse… it will increase the likelihood of the next neuron firing (by the amount of weighting on the second neuron).
That should be fundamentally equivalent to the effect caused by a hypothetical “negative” action potential and a hyper-polarising synapse… and vice versa.
I think I my biology was more rusty than yours, I was confusing inhibitory postsynaptic potentials with “negative action potentials”. It looks like there is only one type of action potential coming out of a neuron along an axon, the positive/negative weighting occurs at synaptic junctions carrying over to integration on the dendrite.
That should be fundamentally equivalent to the effect caused by a hypothetical “negative” action potential and a hyper-polarising synapse… and vice versa.
Yes, that was what I was thinking when I (accidently) made up that term.
From my understanding most synapses were more typically like an usigned scalar weight, and the sign component comes from the action potential itself—which can be depolarizing or hyper-polarizing.
A hyperpolarization has a negative sign—it lowers the membrane potential voltage, a depolarization has a positive sign—raising the membrane potential voltage.
From what I remember neurons tend to specialize in one or the other (+polarization or -polarization based on their bias level), but some synaptic interactions may be able to reverse the sign as well (change an incoming + polarization into a -polarization, or vice versa). However, I’m less sure about how common that is.
Ok.
So perhaps I do not understand what you mean when you talk about a “negative action potential”
From my (admittedly rusty) neurobiology, synapses increase or decrease the likelihood of the next neuron reaching action potential and firing.
If the first neuron has a “positive” action potential and a depolarizing synapse… it will increase the likelihood of the next neuron firing (by the amount of weighting on the second neuron).
That should be fundamentally equivalent to the effect caused by a hypothetical “negative” action potential and a hyper-polarising synapse… and vice versa.
I think I my biology was more rusty than yours, I was confusing inhibitory postsynaptic potentials with “negative action potentials”. It looks like there is only one type of action potential coming out of a neuron along an axon, the positive/negative weighting occurs at synaptic junctions carrying over to integration on the dendrite.
Yes, that was what I was thinking when I (accidently) made up that term.