Research
The Biology of Difference
No two spines need to look the same for a nervous system to work.
Look closely at the dendrites of a neuron and you may find small projections called dendritic spines. They are often described in simplified diagrams as though they follow one pattern. Actual spines show remarkable variation.
Some have slender necks and small heads. Some appear mushroom-shaped. Others have short, broad profiles. Their sizes, molecular compositions, synaptic relationships and histories can differ. They can also change over time.
We can classify features for research. We can identify recurring relationships. We can build models that help us understand the processes. Yet a category is a way of studying variation, not evidence that every member is identical.
Within Whole System Neuro-Endocrinology, that distinction matters.
A biological system is not a collection of identical parts
Cells function in context. Their membrane potentials, receptor populations, signalling molecules, energy demands and inputs change the conditions under which they operate.
The significance of a signal depends on more than its name. Glutamate, GABA, dopamine and other messengers act through particular receptors and circuits. Hormones operate through feedback systems and target tissues that are changing over time.
The work of a biological system is coordinated through relationships between different structures and states.
Inhibition is part of making action possible
An action is rarely just one signal being turned on. In many circuits, an activity must be shaped, timed or selected in relation to other activities.
Inhibition can limit activity, prevent interference, sharpen timing or help coordinate a pattern. Some neural circuits are disinhibited when existing inhibitory activity is reduced, allowing a downstream process to become more active.
Basal ganglia circuits are one example. Influential models and experimental research describe how desired actions can be facilitated while competing motor programmes are suppressed. Direct and indirect pathway interactions are more complex than a simple accelerator and brake, and both pathways may participate in action selection.
The important research questions are specific: Which circuit? Which cell? Which receptor? What timing? What competing activity? What is measured?
The question "what must be inhibited for something to work?" is valuable when examined circuit by circuit. It should not be turned into a universal claim that all biological functions require another function to be inhibited, or that one dendritic spine necessarily inhibits another spine.
The role of the spine
Dendritic spines are predominantly postsynaptic sites for excitatory connections. Much inhibitory signalling in the same networks occurs on dendritic shafts, cell bodies and other compartments, with important exceptions and special cases. Individual spines also contain molecular machinery that regulates the size and effect of excitatory inputs.
A spine belongs within an intricate landscape of synaptic integration, modulation and plasticity. Its shape is informative, but it cannot by itself explain a person's behaviour or a social judgement.
Biological difference and human normality
Here is where the school's questions become interesting.
If living systems contain variation at every scale, why are people so often expected to match a narrow account of normal experience or behaviour?
Biology provides evidence about structures and processes. It does not automatically tell us which educational rules are fair, which identities have value, or what kind of society should exist. Those questions require ethics, dialogue, law, experience and an understanding of consequences.
We can celebrate the beauty of biological difference while being careful about what science actually demonstrates.
Learning without forcing everything into one explanation
The School of Abnormal explores connections between biology, behaviour and the social world. WSNE and Permission Architecture offer routes into the questions. Neither should be protected from criticism.
Where established neuroscience offers a clear answer, we should explain it precisely. Where an idea is a hypothesis, we should say so. Where a metaphor helps someone understand, we should identify it as a metaphor. Where the evidence is missing, the question remains open.
Questions to take further
- What can a spine's structure tell us about its function, and what can it not tell us?
- How do inhibitory, excitatory and modulatory signals interact in a particular circuit?
- How does activity at one scale influence what can happen at another?
- How do learning, hormone states and environmental conditions change that interaction?
- What would make us revise a favourite explanation?
Difference is fundamental to life. The meaning we attach to difference is something we can question.
Scientific sources for editorial review
The following reviews support the established neuroscience described above. Their presence does not validate every proposed WSNE or Permission Architecture application.