# The Forebrain

Psychology I · Behavioral Biology · https://tryals.app/learn/psychology-i/the-forebrain

## Subcortical Structures

The **forebrain** contains subcortical regulatory systems and the cerebral cortex. The **thalamus** is the central sensory relay station, routing nearly all incoming sensory input to the correct cortical area. **Pitfall:** smell bypasses the thalamus entirely, projecting straight to limbic targets.

The **hypothalamus** is the master regulator of homeostasis, controlling hunger, thirst, temperature, and sexual behavior while directing the pituitary gland. The **basal ganglia** govern voluntary movement initiation and procedural learning; their dysfunction causes Parkinson's and Huntington's disease.

## The Limbic System

The **limbic system** governs emotion, motivation, and memory through structures like the hippocampus and amygdala.

| Structure | Core role |
|---|---|
| **Hippocampus** | New declarative memory, spatial navigation |
| **Amygdala** | Fear and emotional memory |

**Common pitfall:** patient H.M. lost his hippocampi and could no longer **form** new long-term memories. But he kept old childhood memories, proving the hippocampus is required for creation, not permanent storage.

## Practice questions

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

### 1. Most people recall where they were when they heard shocking news, and recall a normal Tuesday hardly at all. Which structure explains the difference, and what is it doing?

A. The hippocampus alone, because emotional events are rehearsed more often afterwards
B. The hypothalamus, whose stress hormones improve memory for everything equally
C. The amygdala, which tags the event as significant while encoding
D. The thalamus, which routes emotional material along a privileged pathway

**Answer:** C. The amygdala, which tags the event as significant while encoding

**Why:** The hippocampus writes the memory; the amygdala marks it as worth writing well. Patients with amygdala damage lose the emotional advantage and keep normal memory for neutral material. One caution: these memories feel far more accurate than they are, vividness and accuracy are strengthened separately.

Page: https://tryals.app/practice/psychology-i/the-forebrain/most-people-recall-where-they-were-when-they-heard-shocking-news-and

### 2. Patient H.M. had both hippocampi removed. Sort each ability by whether he LOST it or RETAINED it.

**Answer:**

- Lost after surgery: Learning a new person's name and face, Remembering what he ate for lunch an hour ago, Forming a memory of a new fact he just read
- Retained after surgery: Recalling his own childhood, Gradually improving at a mirror-drawing motor task with practice

**Why:** H.M. lost the ability to form new declarative memories (new names, recent lunch, new facts) but retained old memories (childhood) and could still learn new motor skills (mirror-drawing). The hippocampus is needed to FORM new declarative memories, not to store old ones or learn procedures.

Page: https://tryals.app/practice/psychology-i/the-forebrain/patient-h-m-had-both-hippocampi-removed-sort-each-ability-by

### 3. After both hippocampi were removed, patient H.M. practised mirror-drawing daily and got steadily better at it - while insisting at every session that he had never attempted the task before. Why is being better at something you cannot remember learning evidence for more than one memory system?

A. Because his memory was not lost, only inaccessible to speech.
B. Because motor skills are stored in the muscles, not the brain.
C. Because the improvement and the recollection came apart.
D. Because the hippocampus stores only older memories.

**Answer:** C. Because the improvement and the recollection came apart.

**Why:** A dissociation is how neuropsychology argues: one store would have to lose both or keep both, and his error curve fell like anyone else's while his report stayed empty. He was not failing to express an intact memory, he was reliably surprised by the task every session, including when it was described to him.

Page: https://tryals.app/practice/psychology-i/the-forebrain/after-both-hippocampi-were-removed-patient-h-m-practised

### 4. Select every statement that is TRUE about the forebrain.

A. The basal ganglia are mainly responsible for producing spoken language.
B. The hypothalamus controls the pituitary gland.
C. H.M. was unable to learn any new motor skills after his surgery.
D. The amygdala strengthens memory for emotionally charged events.
E. Smell is the sensory pathway that does NOT route through the thalamus.

**Answer:** B. The hypothalamus controls the pituitary gland.; D. The amygdala strengthens memory for emotionally charged events.; E. Smell is the sensory pathway that does NOT route through the thalamus.

**Why:** Smell bypasses the thalamus, the hypothalamus controls the pituitary, and the amygdala boosts emotional memory - all true. H.M. COULD still learn new motor skills (procedural memory spared), and the basal ganglia handle movement/procedural learning, not speech production.

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

### 5. Order how a new emotionally charged memory gets encoded.

**Answer:**

1. An emotionally arousing event occurs.
2. The amygdala flags it as emotionally significant.
3. The hippocampus binds it into a new long-term declarative memory.
4. Later, the memory can be recalled as a fact or event.

**Why:** The amygdala tags the event's emotional significance, boosting the hippocampus's formation of a durable declarative memory that can later be recalled. Emotional tagging is why charged events are remembered more strongly than neutral ones.

Page: https://tryals.app/practice/psychology-i/the-forebrain/order-how-a-new-emotionally-charged-memory-gets-encoded