IB Bio SAQ Intros

Technological Techniques

Advanced imaging methods used to study brain structure (anatomy) and function (activity). They allow psychologists to correlate observed brain activity/structure with specific behaviors or cognitive processes

MRI (Magnetic Resonance Imaging)

Uses powerful magnetic fields to create detailed structural images of brain tissue. Helps identify tumors, lesions, or developmental abnormalities.

fMRI (functional MRI)

Measures blood oxygen levels (blood flow changes) to show which brain areas are active during specific tasks (e.g., memory recall, language). Has high spatial resolution (precision in location).

Historical Techniques

Earlier methods like post-mortem examinations (e.g., Broca ), lesion studies (e.g., Phineas Gage, H.M. ), and EEG(measuring electrical activity ). These provide pre-fMRI context for studying the brain

Localization of Function

The idea that specific brain regions control particular functions. It provides a fundamental framework in neuroscience (e.g., motor cortex controls movement, hippocampus for memory).

Supporting Evidence

Examples of specialization: Broca's area for speech production ; the visual cortex for sight ; and how strokes/disease affect specific regions (e.g., Alzheimer's initially affecting memory regions)

Limitations/Modern View

Strict localization is oversimplified. Most complex functions (like language) emerge from networks spanning multiple brain regions. The brain also shows plasticity (functions can shift after injury)

Functional Distribution

A concept challenging strict localization: A single function (e.g., language) often depends on multiple brain regionsworking together

Neural Networks

Circuits built from individual neurons that communicate through synapses. Activity creates cascading patterns that coordinate complex functions across distributed brain areas. Modern view emphasizes connectivity

PFC-Amygdala Circuit

An example of a network, often called the emotion regulation network or fear circuit. It involves bidirectional communication.

Function of the Circuit

The Prefrontal Cortex (PFC) sends inhibitory signals to the amygdala to regulate and calm emotional responses (emotional regulation). It also helps with fear extinction and decision-making under emotional conditions.

Clinical Relevance

Disrupted PFC-amygdala connectivity is implicated in mental disorders like anxiety, PTSD, and depression

Hormones

Chemical messengers produced by endocrine glands that travel through the bloodstream. They create widespread effects on brain function and behavior, unlike neurotransmitters that work at specific synapses.

Cortisol

primary stress hormone. Prolonged exposure (chronic stress) damages the body. Moderate levels enhance memory, but high levels impair it (e.g., during extreme stress).

Other Key Hormones

Testosterone influences aggression and competition. Estrogen affects mood and cognition. Oxytocin promotes social bonding and trust.

Berthold (1849)

Historical study showing that chemical signals (later identified as hormones from the testes) affected behavior (aggressiveness) in roosters