Basic Zombie

Field note. Subject advances at a slow, even pace and stops only to eat whatever plant is in its path. It makes no attempt to avoid incoming fire. After losing its head, it keeps walking for a moment before falling.

Predict first

Review the field notes and then consider how to explain the zombie’s behavior.

Before you open the report: why do you think these two brains are different? How is the zombie behavior explained by the differences?

Scans

Control brain

The same view of the zombie’s brain. The prefrontal cortex and amygdala are smaller than in the control brain and look damaged, with cracks and ragged edges. Because the prefrontal cortex is smaller, the front of the brain ends further back; a dashed line shows where a typical brain’s front edge would be. The cerebellum and brainstem look typical. The spinal cord is thick, zombie green, and braided like a reinforced cable.

Zombie brain

AI-drawn image. Not yet checked by an expert; may contain anatomical errors and, obviously, is not detailed enough to be accurate.

Region guide

Cerebral cortex: The brain’s wrinkled outer layer. Handles higher functions such as thinking, language, and perception; the prefrontal cortex is one part of it.
Prefrontal cortex: The front of the frontal lobe. Supports planning and higher-level thinking.
Amygdala: A small, almond-shaped area deep in the temporal lobe. Processes emotion, especially fear and aggression.
Hippocampus: A curved structure deep in the temporal lobe. Helps form new memories of facts and events.
Basal ganglia: A group of structures deep in the brain. Help control movement and form habits.
Corpus callosum: A thick band of nerve fibers connecting the left and right halves (hemispheres) of the brain so they can share information.
Cerebellum: At the back, below the cortex. Controls balance and coordination; helps with skills and habits.
Thalamus: The brain’s sensory relay station. Passes along information from every sense except smell.
Hypothalamus: Below the thalamus. Keeps the body in balance (temperature, appetite) and helps trigger fight or flight.
Pituitary gland: A pea-sized gland hanging below the hypothalamus, which controls it. Called the “master gland” because its hormones direct many other glands in the body.
Brainstem: Connects the brain to the spinal cord. Runs automatic functions such as breathing and heart rate.
Pons: Part of the brainstem. Connects the lower brainstem and cerebellum with the rest of the brain and helps regulate brain activity during sleep.
Spinal cord: Not part of the brain. Carries messages between the brain and body and runs some reflexes on its own.

Sources: Spielman et al. (2020), §3.4, §3.5, §8.2, §10.4; basal ganglia from Cleveland Clinic (2022). (Unchecked by a person; AI research only.)

Brain report

(open it after you make your guess)

What’s different. This zombie’s prefrontal cortex and amygdala are smaller than the control brain’s and look damaged. Its cerebellum and brainstem look typical, and its spinal cord is unusually thick.

Why it might not plan. The prefrontal cortex supports higher-level thinking such as planning (Spielman et al., 2020, §3.4). (Unchecked by a person; AI research only.) With less of it, the zombie might head in a straight line instead of looking for a better route.

Why it might not dodge. The amygdala helps process emotion, especially fear (Spielman et al., 2020, §8.2). (Unchecked by a person; AI research only.) A smaller amygdala could mean a weaker response to danger, which might explain why the zombie keeps coming under fire.

How it still walks. Walking steadily takes balance and coordination, and the cerebellum handles those (Spielman et al., 2020, §3.4). (Unchecked by a person; AI research only.) This zombie’s cerebellum looks typical.

How it might walk without a head. In people, the spinal cord handles some reflexes without the brain, such as pulling your hand away from something hot (Spielman et al., 2020, §3.4). (Unchecked by a person; AI research only.) Animal research suggests the spinal cord also contains circuits that can produce a basic stepping rhythm (Guertin, 2009). (Unchecked by a person; AI research only.) This zombie’s extra-thick spinal cord might let it keep stepping for a moment after losing its brain. A human couldn’t do this.

Real-brain takeaway

The prefrontal cortex supports planning and higher-level thinking.
The amygdala processes emotion, especially fear.
The cerebellum handles balance and coordination.
The spinal cord carries messages between the brain and body and runs some reflexes on its own.

Sources for this page

Guertin, P. A. (2009). The mammalian central pattern generator for locomotion. Brain Research Reviews, 62(1), 45–56. https://doi.org/10.1016/j.brainresrev.2009.08.002 (Unchecked by a person; AI research only.)

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020). Psychology 2e. OpenStax. https://openstax.org/details/books/psychology-2e (Free to read) (Unchecked by a person; AI research only.)

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