In the given structure of the human brain below :
Cerebral cortex, thalamus, limbic system , corpora quadrigemina , hypothalamus, brain stem, cerebral aqueduct, cerebellar hemisphere.
How many structures are associated with the forebrain of human ?

Options

A. Three
B. Four
C. Five
D. Six

Answer

To determine how many structures are associated with the forebrain of humans from the given list, we need to identify which of the listed structures belong to the forebrain. The forebrain consists of several key components. Let's analyze the provided structures step by step.

### Step-by-Step Solution:

1. **Identify the Structures**:
The structures mentioned in the question are:
- Cerebral cortex
- Thalamus
- Limbic system
- Corpora quadrigemina
- Hypothalamus
- Brain stem
- Cerebral aqueduct
- Cerebellar hemisphere

2. **Classify Each Structure**:
- **Cerebral cortex**: This is part of the forebrain and is responsible for higher brain functions such as thought and action.
- **Thalamus**: This is also part of the forebrain and acts as a relay station for sensory and motor signals.
- **Limbic system**: This is part of the forebrain and is involved in emotions and memory.
- **Corpora quadrigemina**: This is part of the midbrain, not the forebrain.
- **Hypothalamus**: This is part of the forebrain and regulates various autonomic functions.
- **Brain stem**: This is not part of the forebrain; it includes structures like the midbrain, pons, and medulla.
- **Cerebral aqueduct**: This is a channel in the midbrain, not part of the forebrain.
- **Cerebellar hemisphere**: This is part of the hindbrain, not the forebrain.

3. **Count the Forebrain Structures**:
From the analysis, the structures that belong to the forebrain are:
- Cerebral cortex
- Thalamus
- Limbic system
- Hypothalamus

Thus, there are **4 structures** associated with the forebrain.

4. **Conclusion**:
The correct answer to the question is **4**.