Study Notes on Brain Basics and Trauma

Importance: Understanding brain basics is critical for analyzing how trauma affects the brain.

Location: At the very front of the brain.
Notable Area: Prefrontal Cortex
- Also Known As: Rational brain or neocortex.
- Function: Responsible for executive functioning, including higher order thinking processes such as:
- Planning
- Decision-making
- Problem-solving
- Development: Does not fully mature until approximately age 25, which explains why children may require assistance with time management and consideration of consequences.

Location: Central part of the brain.
Function: Regulates bodily functions including:
- Body temperature
- Sense of homeostasis
- Homeostasis Defined: The process of maintaining a stable internal environment despite external changes.

Part of: Limbic system, involved in emotion and motivation.
Function: Plays a pivotal role in learning and memory, functioning as a filing cabinet for the brain.
- Not the sole area associated with learning and memory but significantly involved in these processes.

Part of: Limbic system, linked to emotions.
Function: Processes threats and triggers the fight, flight, or freeze response, crucial for understanding trauma.

Development Pattern: Human brains evolved from back to front and inside out:
- Oldest Part: Reptilian Brain (Instinctual Brain)
- Keeps us alive by regulating vital functions like breathing and heart rate.
- Middle Part: Limbic System (Emotional Brain)
- Houses the hippocampus and amygdala.
- Newest Part: Neocortex (Rational Brain)
- Responsible for higher-order cognitive functions.
Note: This model, while simplified, aids in understanding brain function under stress.

Development Pattern: Each human brain also develops from back to front and inside outward, starting in utero and progressing after birth.
Communication in Brain: Important for understanding interplay between the rational neocortex and emotional limbic system.

Definition of Neurons: Neurons are the building blocks of the nervous system. The human brain has approximately $100,000,000,000$ neurons.
Function: Neurons serve as communication centers, continuously sending and receiving signals that enable functioning.

Main Parts:
- Dendrites: Branch-like structures that receive signals from nearby neurons, acting as receivers of messages.
- Cell Body (Soma): Contains the nucleus and processes received signals.
- Axon: A long appendage that transmits electrical signals away from the cell body, covered by a myelin sheath to facilitate signal speed.

Signal Reception: Dendrites receive chemical messages from adjacent neurons.
Chemical to Electrical Conversion: Received chemical messages are converted into electrical signals (action potentials) in the cell body.
Propagation: Electrical signals travel down the axon to the axon terminal, where they are converted back into chemical messages.
Synapse: Neurons do not touch; there exists a synaptic gap where neurotransmitters bridge the gap for communication.
Key Takeaway: An electrical impulse is sent out and picked up by dendrites of the next neuron, restarting the communication process.

Definition: The capacity of the brain to adapt and change, with implications for both learning and stress response.
Key Concepts:
- Neurons that Fire Together, Wire Together: This principle indicates that repeated activation strengthens neural pathways.
- Use-It-or-Lose-It: Connections that are rarely activated weaken over time.
Implication: Changes based on experience lead to stronger neural circuits for skills or behaviors practiced frequently.

Categories:
- Excitatory Neurotransmitters: Promote neuronal firing; examples include:
- Glutamate
- Epinephrine
- Norepinephrine
- Inhibitory Neurotransmitters: Prevent neuronal firing; examples include:
- Serotonin
- GABA
- Modulatory Neurotransmitters: Adjust the effects of other neurotransmitters; example:
- Serotonin (both inhibitory and modulatory)

Post-Synaptic Process: After transmission, neurotransmitters can either:
- Fade away
- Be reabsorbed (reuptake)
- Be broken down by enzymes (degradation)

Dopamine: Involved in motor behavior, motivation, and pleasure.
Acetylcholine: Initiates motor movement and relates to attention, learning, and sleep.
Endorphins: Affect emotions and pain perception.
Serotonin: Influences mood, arousal, eating, aggression, and sleep.
Chemical Transmission: Healthy brain function depends on the balance and regulation of neurotransmitters rather than their mere presence at high or low levels.

Drug Categories:
- Agonists: Increase neurotransmitter activity, enhancing their effects.
- Antagonists: Block or reduce neurotransmitter effects.
Examples:
- SSRIs (Selective Serotonin Reuptake Inhibitors): Medications like Prozac and Zoloft work as indirect agonists by preventing serotonin reuptake, keeping levels higher in the synaptic gap.
- Popular Myth: Depression caused solely by low serotonin levels has been largely debunked, despite widespread belief influenced by pharmaceutical marketing.

SSRIs:
- Do not address the underlying causes of trauma-related distress, although they may assist in managing symptoms.
Alcohol: Acts as an agonist for GABA, enhancing calming effects.
Stimulants: Often agonists for dopamine, increasing pleasure sensations.
Caffeine: Acts as an antagonist for adenosine, inhibiting sleep-inducing signals.

Principle: The body seeks homeostasis; an increase in neurotransmitter activity can lead to subsequent drops in that activity, resulting in cravings following drug use.
Effect of Trauma: Trauma can alter perceived norms within our nervous systems, influencing homeostasis.

This overview emphasizes the complex interplay of different brain regions, neurotransmitter systems, and the impact of trauma on brain function and communication.