Habit formation: From the cellular perspective

Habits are an essential aspect of our daily lives as they help us to carry out routine activities without requiring conscious effort. Habits are formed when a behavior is repeatedly performed, leading to a process called ‘habituation,’ which involves changes in neural networks in the brain. However, the formation of habits goes beyond the brain and is, in fact, a process that occurs at a cellular level. Habit formation has been shown to involve changes in cell morphology, gene expression, and protein synthesis. In this blog, we’ll explore the cellular processes involved in habit formation.

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Forming Habits – The Role of NMDA Receptors

To understand how habits are formed at a cellular level, we need to start with the basics of how neurons communicate with one another. At the synapse, where neurons communicate, neurotransmitters are released from one neuron to the other. These neurotransmitters bind to receptors on the receiving neuron and create an electrical signal. One particular receptor type, called the NMDA receptor, is essential for the formation of new habits. The NMDA receptor is activated when the neuron membrane is depolarized, and its activity leads to the promotion of long-term potentiation (LTP), which is the stereotypical cellular process involved in learning.

LTP is a process that involves an increase in the strength of synapses between neurons. This increased synaptic strength occurs because the activation of the NMDA receptor stimulates the release of calcium ions in neurons, which then acts to signal genetic changes in the nucleus. This chain of events eventually leads to an increase in the production of proteins that build and maintain synapses. The resulting growth of new synapses, or strengthening of existing ones, means that the neurons that fire together wire together, resulting in the formation of new habits.

The Role of Protein Synthesis

Protein synthesis plays a critical role in the formation of new habits at a cellular level. In response to repeated activation of neurons, long-term changes occur in gene expression, resulting in new proteins being produced in neurons. These new proteins are then used to build and maintain synapses, leading to an increase in their density and function. New proteins also enable neurons to alter their behavior, for example by decreasing or increasing their excitability. Both of these processes lead to the formation of a new neural pathway, which, with repetition, can become habitual behavior.

The Role of Glial Cells

While neurons and synaptic activity are the primary focus of habit formation, glial cells also play a significant role. Glial cells support neurons and provide them with metabolic and structural support. Recent studies have shown that these cells play an active role in synaptic plasticity. Glial cells can undergo changes in gene expression and protein synthesis in response to neural activity, leading to their contribution to the signaling that leads to habit formation.

Conclusion

In conclusion, habits are formed at a cellular level through a process involving NMDA receptors, protein synthesis, and the support of glial cells. These cellular processes occur in response to repetitive stimulation of neurons, leading to the strengthening of existing synapses, the formation of new ones, and changes in gene expression patterns. Understanding these cellular processes that lead to habit formation can provide insight into developing new therapies for habit-forming and addictive behaviors.