The Brain & Tools for Studying It
- Locate major brain structures and state the function of each
- Explain the roles of the two cerebral hemispheres and the cortex lobes
- Compare the tools neuroscientists use to study brain structure and activity
From brainstem to cortex
The brain is layered from old survival structures up to newer thinking ones. The brainstem houses the medulla (heartbeat, breathing) and, above it, the reticular formation (arousal). The cerebellum ("little brain") coordinates balance and smooth movement. The limbic system handles emotion and memory: the amygdala (fear and aggression), the hippocampus (forming new memories), and the hypothalamus (hunger, thirst, body temperature, and the "four F’s" — plus control of the pituitary gland). Wrapping it all is the wrinkled cerebral cortex, the seat of higher thought.
The four lobes and the split brain
The cortex has four lobes per hemisphere. The frontal lobe governs judgment, planning, and voluntary movement (via the motor cortex) — the case of Phineas Gage, whose personality changed after a rod destroyed his frontal lobe, revealed its role. The parietal lobe processes touch (the somatosensory cortex). The occipital lobe processes vision. The temporal lobe processes hearing and, in the left hemisphere, language. Roger Sperry and Michael Gazzaniga’s split-brain studies (cutting the corpus callosum that joins the hemispheres) showed the left hemisphere specializes in language and the right in spatial and holistic processing.
Tools for studying the brain
Neuroscientists match the tool to the question. Lesion studies destroy tissue to see what function is lost. The EEG records overall electrical activity through the scalp — great for sleep stages and timing. CT and MRI scans reveal brain structure (anatomy), while fMRI and PET scans reveal function by tracking blood flow or glucose use as a person performs a task — showing which regions light up. A rule of thumb: MRI/CT = "what the brain looks like," fMRI/PET = "what the brain is doing."
A patient survives a stroke that damages the rear of the left frontal lobe. Afterward she can understand speech but struggles to produce fluent, grammatical sentences. Explain which structure was likely affected and why the deficit fits.
- 1.Identify the region: the rear of the left frontal lobe is the location of Broca’s area, which controls speech production.
- 2.Recall Broca’s area’s function: it enables the muscle coordination and grammar needed to produce fluent speech, not to comprehend it.
- 3.Match symptom to region: comprehension is intact (that relies on Wernicke’s area in the temporal lobe), but production is impaired — exactly the profile of Broca’s aphasia.
- 4.Conclude with the localization logic: damage to a specific area removes a specific function, demonstrating the brain’s localization of language.
A gymnast recovering from a head injury can think and speak normally but has lost her balance and the smoothness of her movements. Which brain structure was most likely damaged?
Anchor the limbic trio with a mnemonic: Amygdala = Alarm (fear), Hippocampus = Holding new memories, Hypothalamus = Homeostasis (hunger, thirst, temperature). The overlap in "H" is worth extra rehearsal since these two are easily swapped.
A researcher wants to see which brain regions become active while participants solve math problems. Which tool is the best choice?
When a question distinguishes brain-imaging tools, sort by structure vs. function: CT/MRI = structure (a photograph), fMRI/PET = function (a movie of activity), EEG = electrical activity over time. Naming the structure/function split usually earns the point on FRQs.
Answer the 2 checkpoints as you read.
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