Guest speaker 1: The Adolescent Brain

Question 1

What are dendrites? [1]

Answer 1

Branch-like structures that receive signals from other neurons.

Question 2

What is the cell body? [1]

Answer 2

contains the nucleus and helps send the signal down the axon.

Question 3

How do neurons send information? [1]

Answer 3

Neurons send info via action potentials (electrical impulses).

Question 4

What happens at the synapse? [1]

Answer 4

When a nerve impulse reaches the synapse, it may release neurotransmitters (NT) to communicate with other neurons.

Question 5

What are neurotransmitters (NTs)? [1]

Answer 5

chemicals like monoamines, glutamate, and GABA that help transmit signals across the synapse.

Question 6

How many neurons are there in the human body? [1]

Answer 6

around 100 billion

Question 7

Why is the brain folded? [1]

Answer 7

to increase surface area, allowing for more neural connections.

Question 8

What is grey matter? [1]

Answer 8

forms the outer layer of the brain, called the cerebral cortex or neocortex.

Question 9

What is white matter? [1]

Answer 9

located in the inner layers of the brain and helps with communication between brain areas.

Question 10

How is the brain divided? [2]

Answer 10

• two hemispheres
• several lobes.

Question 11

What is the corpus callosum? [1]

Answer 11

structure that connects the two hemispheres, allowing them to communicate.

Question 12

How does MRI work? [1]

Answer 12

by displacing and re-aligning protons in a magnetic field, generating a signal based on their movement.

Question 13

What is the principle behind fMRI? [1]

Answer 13

measures energy requirements of active brain regions to create images based on brain activity.

Question 14

How does PET work? [1]

Answer 14

injecting a radioactive tracer; as it decays, it emits gamma rays, which are detected to measure brain activity and biochemistry.

Question 15

What does EEG measure? [1]

Answer 15

voltage changes at the scalp surface, providing a direct measure of brain electrical activity (summed across pyramidal neurons).

Question 16

What is Event-Related Potential (ERP)? [1]

Answer 16

the average of neural activity following a stimulus, calculated by averaging multiple EEG recordings.

Question 17

What does CT stand for and how does it work? [2]

Answer 17

• Computed Tomography
• it takes detailed images of brain structures using X-rays.

Question 18

What is DTI and how does it work? [1]

Answer 18

• Diffusion Tensor Imaging
• tracks the movement of water protons along axons, revealing axonal pathways in the brain.

Question 19

What happens to the brain after birth? [1]

Answer 19

Grows rapidly, producing billions of neurons and forming synapses (connections between neurons) through a process called synaptogenesis.

Question 20

How much does the brain grow in the first 2 years? [1]

Answer 20

from 25% to 75% of its adult weight

Question 21

What is synaptic pruning? [1]

Answer 21

the gradual disappearance of synapses based on experience, eliminating unnecessary connections between neurons.

Question 22

When does pruning continue? [1]

Answer 22

into late adolescence/early adulthood, especially in the prefrontal cortex (PFC), which matures into the early 20s.

Question 23

Why has the definition of adolescence expanded? [1]

Answer 23

due to new insights about brain development profiles, particularly in the frontal lobe.

Question 24

What is the role of the prefrontal cortex (PFC)? [4]

Answer 24

regulates:

• decision-making/planning
• judgment
• emotional expression
• impulse control

Question 25

What is the role of the limbic system during adolescence? [1]

Answer 25

helps process and manage emotions and is still developing during adolescence, impacting emotional regulation.

Question 26

Why do adolescents experience more mood swings and impulsive behavior? [1]

Answer 26

because the limbic system is not fully inhibited by the still-maturing PFC.

Question 27

What [3] changes occur in the adolescent brain related to pleasure?

Answer 27

* becomes **more sensitive to dopamine** * with **more dopamine receptors** and enhanced supply * leading to **feelings of pleasure** during activities.

Question 28

How does this sensitivity to pleasure affect adolescents? [4]

Answer 28

can lead to: * greater **sensation-seeking** * **novelty-seeking** * **self-regulation issues** * changes in **motivation**.

Question 29

How do gonadal hormones affect sex differentiation? [2]

Answer 29

* Gonadal hormone secretions from the testis in males lead to **masculinization** * both males and females have **androgens**, **estrogens**, and **progesterone**, but in different levels and patterns.

Question 30

What role does testosterone play in male brain development? [1]

Answer 30

**testosterone** and its conversion to **estrogen** in utero cause **masculinization** of the fetal brain.

Question 31

How does the absence of androgens affect female brain development? [1]

Answer 31

the absence of androgen production and the presence of **alpha-fetoprotein** lead to **feminization** of the fetal brain.

Question 32

What are the average brain weights for males and females? [2]

Answer 32

* Males: 1260g * Females: 1130g | ***10% larger in males***

Question 33

What structural differences exist in male and female brains? [2]

Answer 33

* Males: higher % of white matter and cerebrospinal fluid (CSF) * Females: higher % of gray matter

Question 34

What are some behavioral differences between males and females? [2]

Answer 34

* Males: enhanced **motor** and **spatial** skills * Females: excel in **memory** and **social cognition** (like emotion identification) and **verbal fluency**.

Question 35

How does cortical thickness vary between males and females? [2]

Answer 35

* Males: thinning in frontal regions * Females: thinning in posterior regions

Question 36

What findings were observed in a study on structural connectivity between 8-22 years? [2]

Answer 36

* Males: more intra-hemispheric connectivity * Females: dominance in inter-hemispheric connectivity (frontal lobe)

Question 37

What networks show higher structural connectivity in females? [2]

Answer 37

* Reward processing * Memory

Question 38

How does brain perfusion relate to brain activity needs? [2]

Answer 38

* Males have **decreased** perfusion in insula and amygdala * Females: **increased** perfusion in insula and amygdala

Question 39

What is the relationship between anxiety and brain perfusion in females? [1]

Answer 39

Higher **trait anxiety** in post-pubertal females is linked to increased perfusion in the **left amygdala.**

Question 40

What is the potential benefit of aerobic exercise for depressed youth? [1]

Answer 40

(cardio) is a promising alternative treatment for Major Depressive Disorder (MDD) in youth.

Question 41

How can repeated cardio exercise benefit the brain? [4]

Answer 41

* **Increase neurotrophic** factors (molecules that support neuron growth). * **Modulate serotonin and norepinephrine** (chemicals involved in cognition and mood). * **Enhance HPA-axis** regulation (the stress response system). * **Reduce inflammation**.

Question 42

What are the potential outcomes of the benefits of aerobics? [3]

Answer 42

* **New neuron** formation. * **Increased connections** between neurons. * Enhanced **brain vasculature**.

Question 43

What is the impact of chronic cannabis use on the adolescent brain? [1]

Answer 43

may **alter brain structure and function**, particularly in adolescents who may be more sensitive to THC.

Question 44

What complicates the understanding of cannabis effects? [2]

Answer 44

* poverty * abuse

Question 45

What recent findings have emerged regarding cannabis use and mental health? [1]

Answer 45

daily cannabis use is associated with increased odds of developing a **psychotic disorder** compared to non-users