# The Cerebral Cortex

Psychology I · Psychophysiology · https://tryals.app/learn/psychology-i/the-cerebral-cortex

## The Thinking Surface

The **cerebral cortex** is the deeply folded outer layer of the cerebrum, the wrinkled grey surface where perception, thought, language, and voluntary action come together. Its folds pack a massive surface area into the skull.

The cortex is split into four distinct **lobes**:

| Lobe | Location | Core functions |
| --- | --- | --- |
| Frontal | Front | Planning, judgment, movement, personality |
| Parietal | Top-rear | Touch, body sense, spatial processing |
| Temporal | Sides | Hearing, language comprehension, memory |
| Occipital | Rear | Vision |

**Common pitfall:** assuming each lobe works in isolation. Complex behavior draws on multiple lobes at once.

## Cortex Strips & Networks

Two strips straddle the frontal-parietal boundary. The **motor cortex** (rear of the frontal lobe) sends commands for voluntary movement. The **somatosensory cortex** (front of the parietal lobe) receives touch and body-position signals.

Both strips are **mapped**: adjacent body parts map to adjacent cortical regions. Highly sensitive or finely controlled areas (hands, lips) get disproportionately large zones.

Vast stretches of cortex are **association areas**. These are not tied to a single sense or muscle; they integrate information across regions to produce planning, language, and abstract thought.

## Practice questions

5 of this lesson's 12 practice questions, with answers. The full set is in the app.

### 1. Damage to Broca's area destroys both the production and the comprehension of language.

**Answer:** False

**Why:** False. Comprehension is largely intact, the patient understands and cannot produce. Wernicke's area supports comprehension and gives the opposite picture: fluent, meaningless speech. That double dissociation is the founding evidence that language is several functions with distinguishable substrates.

Page: https://tryals.app/practice/psychology-i/the-cerebral-cortex/damage-to-brocas-area-destroys-both-the-production-and-the

### 2. On the cortical body map, the hand and lips occupy far more territory than the entire trunk. Why is the map proportioned by something other than body size?

A. Because cortical area tracks receptor density and control precision.
B. Because the trunk is served by the spinal cord directly and bypasses the cortex.
C. Because the map is drawn from the outside inward, and the extremities are mapped first.
D. Because the hands and face are closer to the brain, so their pathways occupy more cortex.

**Answer:** A. Because cortical area tracks receptor density and control precision.

**Why:** Cortex is allocated by information density and precision of control: fingertips discriminate two points a millimetre or two apart, the back several centimetres. And the allocation is not fixed, musicians show enlarged finger representations, and after amputation neighbours expand into the vacated territory. The map is a budget rather than an anatomical diagram.

Page: https://tryals.app/practice/psychology-i/the-cerebral-cortex/on-the-cortical-body-map-the-hand-and-lips-occupy-far-more-territory

### 3. Phineas Gage survived an iron rod through the frontal lobe with intact speech, memory and movement, and his personality changed profoundly. Why did that case reshape thinking about the frontal lobe?

A. Because it showed that damage to any brain region produces the same personality changes.
B. Because it demonstrated that people can survive major brain injury, which had not been known.
C. Because it proved the frontal lobe is responsible for personality alone and plays no role in movement or planning.
D. Because it showed the frontal lobe supports untested abilities.

**Answer:** D. Because it showed the frontal lobe supports untested abilities.

**Why:** Gage mattered because he was normal on everything the nineteenth century knew how to assess, and what changed had never been thought of as a function with a location. The history deserves a caution, the lurid accounts come from a physician writing years later, and he appears to have recovered substantially and driven a stagecoach in Chile.

Page: https://tryals.app/practice/psychology-i/the-cerebral-cortex/phineas-gage-survived-an-iron-rod-through-the-frontal-lobe-with

### 4. In people blind from birth, the **visual** cortex activates during braille reading, and disrupting it impairs their reading. What does that reveal about cortical specialisation?

A. That a region's function depends substantially on the input it receives
B. That the visual cortex was never specialised for vision in the first place
C. That braille is processed visually through an unknown residual pathway
D. That blind people's brains are anatomically different from birth

**Answer:** A. That a region's function depends substantially on the input it receives

**Why:** Activity alone would only show the region is busy; disrupting it and breaking braille reading shows it is doing the work. So cortical tissue is substantially general-purpose, taking its job from its inputs, and it is why early intervention matters so much when a sense is lost, since the territory gets reassigned.

Page: https://tryals.app/practice/psychology-i/the-cerebral-cortex/in-people-blind-from-birth-the-visual-cortex-activates-during

### 5. Select every statement that is TRUE about the cerebral cortex.

A. Each lobe operates entirely independently of the others.
B. The parietal lobe is the primary center for vision.
C. The occipital lobe processes vision.
D. Association areas integrate information across senses and muscles.
E. The frontal lobe handles planning and voluntary movement.

**Answer:** C. The occipital lobe processes vision.; D. Association areas integrate information across senses and muscles.; E. The frontal lobe handles planning and voluntary movement.

**Why:** The frontal lobe's role, the occipital lobe's vision, and the association areas' integrating job are true. Lobes cooperate rather than working in isolation, and vision is occipital (the parietal handles touch and space).

Page: https://tryals.app/practice/psychology-i/the-cerebral-cortex/select-every-statement-that-is-true-about-the-cerebral-cortex