Neuroplasticity, Hyperplasticity & Metaplasticity
Garnet > Lucid Studios
November 8, 2023
Neuroplasticity
Neuroplasticity refers to the capacity of the human brain to make both new functional and structural adaptive changes over time when stimulated with repeated attention based marginal demands.
Such demands may be referred to as Brain Priming experiences.
Hyperplasticity
Hyperplasticity refers to the short-term elevated sensitivity of the brain to incoming bottom-up stimulation following attention based marginal demands.
Such elevated sensitivity is associated with what may be referred to as Brain Time (which follows the Brain Prime experience).
Metaplasticity
Metaplasticity refers to the long-term potentiation of a sustained increased sensitivity and responsiveness to the attention based marginal demands that trigger neuroplasticity.
This new form refers to the plasticity of the plasticity itself, thus the term meta-plasticity.
The idea is that the synapse's previous history of activity determines its current plasticity.
This may play a role in some of the underlying mechanisms thought to be important in memory and learning such as long-term potentiation (LTP), long-term depression (LTD) and so forth.
Recently, it has become clear that the prior history of synaptic activity is an additional variable that influences the synaptic state, and thereby the degree, of LTP or LTD produced by a given protocol.
In a sense, then, synaptic plasticity is governed by an activity-dependent plasticity of the synaptic state; such plasticity of synaptic plasticity has been termed metaplasticity.
THE IMPLICATION OF METAPLASTICITY
The implication of “metaplasticity” is simple yet dramatic – the more one engages neuroplastic processes and enriches the processes in their hyperplastic potential, the better prepared is the brain for even more positive change enabled by the developmentally sustained metaplasticity.
SYNAPTIC STATES AND PREVIOUS ACTIVITY
Research in 2004 has shown that synapses do not strengthen or weaken on a sliding scale.
There are discrete states that synapses move between.
These states are active, silent, recently silent, potentiated, and depressed.
The states which they can move to are dependent on the state that they are in at the moment.
Thus, the future state is determined by the state gained by previous activity.
For instance, silent (but not recently silent) synapses can be converted to active via the insertion of AMPARs in the postsynaptic membrane.
Active synapses can move to either potentiated or depressed via LTP or LTD respectively.
Prolonged low-frequency stimulation (5 Hz, the method used to induce LTD) can move an active synapse to depressed and then silent.
However, synapses that have just become active cannot be depressed or silenced.
Thus, there is state-machine-like behavior at the synapse when it comes to transitions.
However, the states themselves can have varying degrees of intensity.
One active-state synapse can be stronger than another active-state synapse.
This is, in theory, how you can have a strong memory vs. a weak memory.
The strong memories are the ones with very heavily populated active synapses, while weak memories may still be active but poorly populated with AMPARs.
SYNAPTIC REGULATION
The same research has shown that NMDA receptors themselves, once thought to be the control mechanism behind AMPA receptor organization, can be regulated by synaptic activity.
This regulation of the regulation mechanism itself adds another layer of complexity to the biology of the brain.