Cerebral Hemispheres — MCQs
Not seen in case of hemorrhage in MCA territory is:
Corpus callosum involvement on MRI is usually seen in which of the following conditions?
Visual processing center is located in -
What are the effects of a lesion in Brodmann area 22?
Aphasia is most likely associated with a lesion in
Which of the following Brodmann areas is primarily associated with Broca's motor aphasia?
Identify the type of the fibre marked in the image of the internal capsule.
Identify the marked structure in the image.
What is the function of the corpus callosum?
Identify the structure marked by a red arrow in the image.
Cerebral Hemispheres Indian Medical PG Practice Questions and MCQs
Question 1: Not seen in case of hemorrhage in MCA territory is:
- A. Contralateral hemiplegia
- B. Aphasia
- C. Urinary incontinence (Correct Answer)
- D. Dysarthria
Explanation: ***Urinary incontinence*** - Urinary incontinence is typically associated with **anterior cerebral artery (ACA)** territory lesions, which affect the **paracentral lobule** responsible for bladder control. - MCA territory hemorrhage primarily impacts motor, sensory, speech, and attentional functions, not direct bladder control. *Contralateral hemiplegia* - Hemorrhage in the MCA territory commonly affects the **motor cortex** and its descending tracts, leading to **weakness or paralysis** on the opposite side of the body [1]. - This is a very common and expected symptom in MCA strokes. *Aphasia* - If the dominant hemisphere (usually left) is affected,MCA territory hemorrhage often involves **Broca's and Wernicke's areas**, leading to various forms of **aphasia** (expressive or receptive speech difficulties) [1]. - This is a hallmark symptom of dominant MCA strokes. *Dysarthria* - Dysarthria, or difficulty with articulation of speech, can result from MCA territory hemorrhage affecting the motor pathways that control the **muscles of speech** [1]. - It often co-occurs with hemiplegia and other motor deficits.
Question 2: Corpus callosum involvement on MRI is usually seen in which of the following conditions?
- A. SSPE
- B. Phytanic acid deficiency
- C. Krabbe's disease
- D. Butterfly glioblastoma (Correct Answer)
Explanation: ***Butterfly glioblastoma*** - This is a highly malignant brain tumor (WHO Grade IV) that characteristically **crosses the corpus callosum**, allowing it to spread across both cerebral hemispheres, creating a **butterfly-like appearance** on MRI. - The corpus callosum acts as a pathway for tumor spread, leading to bilateral neurological deficits. - This is the **classic and most characteristic** imaging finding associated with corpus callosum involvement. *SSPE (Subacute Sclerosing Panencephalitis)* - SSPE is a rare, progressive brain disorder caused by persistent measles virus infection. - While advanced stages may show periventricular and corpus callosum lesions, the **more characteristic findings** are diffuse white matter T2/FLAIR hyperintensities in the parietotemporal and occipital regions. - Corpus callosum involvement is not the primary or most specific feature. *Phytanic acid deficiency (Refsum disease)* - This is a rare peroxisomal disorder characterized by accumulation of phytanic acid. - MRI typically shows **cerebellar atrophy** and nonspecific white matter changes. - **Corpus callosum is typically spared** in Refsum disease. *Krabbe's disease* - This is a galactocerebrosidase deficiency causing leukodystrophy. - While Krabbe's disease can involve the corpus callosum (particularly the splenium), the **more characteristic and earlier findings** involve the **cerebellar white matter, corona radiata, thalami, and pyramidal tracts**. - Butterfly glioblastoma remains the **most specific** and **most classic** condition associated with corpus callosum involvement on MRI.
Question 3: Visual processing center is located in -
- A. Occipital lobe (Correct Answer)
- B. Frontal lobe
- C. Parietal lobe
- D. Temporal lobe
Explanation: ***Occipital lobe*** - The **occipital lobe** houses the **primary visual cortex**, which is responsible for processing and interpreting visual information received from the eyes [1]. - Damage to this lobe can lead to various visual deficits, including **cortical blindness** or **visual agnosia** [2], [3]. *Frontal lobe* - The **frontal lobe** is primarily involved in **executive functions**, such as decision-making, problem-solving, planning, and voluntary movement. - It also plays a key role in **personality** and social behavior. *Parietal lobe* - The **parietal lobe** integrates sensory information from various parts of the body, including touch, temperature, pain, and pressure. - It also plays a crucial role in **spatial awareness** and navigation. *Temporal lobe* - The **temporal lobe** is mainly associated with **auditory processing**, memory, and language comprehension. - It contains the **primary auditory cortex** and structures vital for forming memories, such as the hippocampus.
Question 4: What are the effects of a lesion in Brodmann area 22?
- A. Expressive aphasia
- B. Receptive aphasia (Correct Answer)
- C. Poor repetition of language
- D. Poor naming
Explanation: ***Receptive aphasia*** - A lesion in **Brodmann area 22**, specifically in **Wernicke's area**, leads to **receptive aphasia** (Wernicke's aphasia). - This condition is characterized by **impaired comprehension** of spoken and written language, **fluent but paraphasic speech**, and **poor repetition**. - This is the most comprehensive answer as it describes the entire clinical syndrome. *Expressive aphasia* - **Brodmann areas 44 and 45** (Broca's area) in the frontal lobe are associated with expressive aphasia (Broca's aphasia). - Patients have good comprehension but struggle to produce fluent speech, with effortful, telegraphic output. *Poor repetition of language* - While poor repetition is indeed a feature of Wernicke's aphasia, this option describes only one component of the syndrome rather than the complete clinical picture. - **Conduction aphasia** (from arcuate fasciculus lesions) is characterized by poor repetition with **relatively preserved** comprehension and fluent speech, distinguishing it from Wernicke's aphasia. - "Receptive aphasia" is the more complete answer. *Poor naming* - Difficulty with naming, or **anomia**, is a common feature across various types of aphasia, including both receptive and expressive aphasia. - It reflects disruption in language networks involving the **temporal and parietal lobes** but is not specific to Brodmann area 22 lesions.
Question 5: Aphasia is most likely associated with a lesion in
- A. Broca's area (Correct Answer)
- B. Primary motor area
- C. Sensory area
- D. Visual area
Explanation: ***Broca's area*** - Lesions in Broca's area lead to **Broca's aphasia**, characterized by **non-fluent speech** and difficulty with **language production**. [1] - This area is located in the **frontal lobe** and is critical for the motor aspects of speech. [1] *Primary motor area* - Damage to the primary motor area primarily causes **weakness** or **paralysis** of voluntary movements. [1] - While it can affect the musculature used for speech, it does not directly cause an **aphasia** where language comprehension or production is impaired at a cognitive level. [1] *Sensory area* - Lesions in the sensory cortex (e.g., primary somatosensory cortex) result in **sensory deficits** like numbness, tingling, or impaired proprioception. [2] - While **Wernicke's aphasia** relates to a sensory language area (Wernicke's area), the term "sensory area" alone is too general and does not specifically pinpoint a region for aphasia. *Visual area* - Damage to the visual cortex (e.g., primary visual cortex in the occipital lobe) leads to **visual field deficits** or blindness. - It does not cause aphasia, which is a disorder of language processing. [1]
Question 6: Which of the following Brodmann areas is primarily associated with Broca's motor aphasia?
- A. 44 (Correct Answer)
- B. 4
- C. 22
- D. 17
Explanation: ***Brodmann Area 44*** - **Brodmann area 44**, also known as **Broca's area**, is located in the inferior frontal gyrus and is critical for **speech production**. - Damage to this area typically leads to **Broca's motor aphasia** (also called expressive aphasia), characterized by **non-fluent speech**, difficulty forming words, and impaired grammar while comprehension remains relatively intact. *Brodmann Area 4* - **Brodmann area 4** corresponds to the **primary motor cortex**, responsible for executing voluntary movements. - While essential for motor control, it is not directly involved in the cognitive aspects of language production that define Broca's aphasia. *Brodmann Area 22* - **Brodmann area 22** is primarily associated with **Wernicke's area**, which is located in the superior temporal gyrus and is crucial for **language comprehension**. - Damage to this area results in **Wernicke's aphasia** (receptive aphasia), characterized by fluent but meaningless speech and impaired comprehension. *Brodmann Area 17* - **Brodmann area 17** is the **primary visual cortex**, responsible for processing visual information. - It plays no direct role in language processing or speech production; damage here would primarily cause visual field deficits.
Question 7: Identify the type of the fibre marked in the image of the internal capsule.
- A. Projection fibers (Correct Answer)
- B. Short association fibers
- C. Long association fibers
- D. Commissural fibers
Explanation: ***Projection fibers*** - The image shows the **internal capsule**, which is a white matter structure composed of **projection fibers** that connect the cerebral cortex to subcortical structures, brainstem, and spinal cord. - These fibers facilitate communication between different levels of the central nervous system, including motor and sensory pathways. *Short association fibers* - These fibers, also known as **U-fibers**, connect adjacent gyri within the **same cerebral hemisphere**. - They are typically located superficially in the cerebral cortex, not deep within the brain as shown in the internal capsule. *Long association fibers* - These fibers connect **different lobes** within the **same cerebral hemisphere**, such as the arcuate fasciculus connecting temporal and frontal lobes. - While they are white matter tracts, they do not constitute the internal capsule, which is specifically known for its extensive projection pathways. *Commissural fibers* - **Commissural fibers** connect corresponding areas in the **two cerebral hemispheres**, with the most prominent example being the **corpus callosum**. - The internal capsule, shown in the image, primarily consists of fibers projecting superiorly and inferiorly, rather than horizontally across hemispheres.
Question 8: Identify the marked structure in the image.
- A. Cerebrum
- B. Brain stem
- C. Corpus callosum
- D. Cerebellum (Correct Answer)
Explanation: ***Cerebellum*** - The image points to the distinct, posterior inferior structure of the brain, characterized by its **folia** and arbour-vitae-like internal structure, which is the cerebellum. - The cerebellum is primarily involved in **motor control**, including coordination, precision, and accurate timing. *Cerebrum* - The cerebrum is the **largest part of the brain**, located superiorly, responsible for higher functions like thought, voluntary movement, and sensory processing. - It consists of two hemispheres connected by the corpus callosum and is characterized by its **gyri** and **sulci**. *Brain stem* - The brain stem is located inferior to the cerebrum and anterior to the cerebellum, connecting the cerebrum and cerebellum to the **spinal cord**. - It controls vital functions such as **breathing**, heart rate, and sleep, and is composed of the midbrain, pons, and medulla oblongata. *Corpus callosum* - The corpus callosum is a large, C-shaped nerve fiber bundle located deep within the brain, under the cerebral cortex. - Its primary function is to **connect the two cerebral hemispheres**, facilitating communication between them.
Question 9: What is the function of the corpus callosum?
- A. Connects the two cerebral hemispheres (Correct Answer)
- B. Regulates autonomic functions
- C. Coordinates motor movements
- D. Processes visual information
Explanation: ***Connects the two cerebral hemispheres*** - The **corpus callosum** is a large, C-shaped nerve fiber bundle found beneath the **cerebral cortex** in the human brain. - Its primary function is to integrate motor, sensory, and cognitive performances between the **cerebral hemispheres**. *Regulates autonomic functions* - This function is primarily associated with the **brainstem** and **hypothalamus**, which control involuntary body processes like heart rate, breathing, and digestion. - The corpus callosum does not directly regulate these functions. *Coordinates motor movements* - **Coordination of motor movements** is largely handled by the **cerebellum**, a distinct part of the brain located at the back of the skull. [1] - While the corpus callosum facilitates communication critical for complex movements, it is not the primary coordinator. [1] *Processes visual information* - The **processing of visual information** primarily occurs in the **occipital lobes** of the cerebral cortex. [2] - The corpus callosum connects these visual areas across the hemispheres but does not perform the processing itself. [2]
Question 10: Identify the structure marked by a red arrow in the image.
- A. Great vein of Galen
- B. Pineal gland
- C. Fornix (Correct Answer)
- D. Falx cerebri
Explanation: ***Fornix*** - The **fornix** is a C-shaped bundle of nerve fibers in the brain that acts as the primary efferent (output) pathway from the hippocampus. - On an axial CT image, the fornix is typically seen as a **thin, arching structure** located above the third ventricle and below the corpus callosum, which matches the position indicated by the red arrow. *Great vein of Galen* - The **Great cerebral vein of Galen** is a large midline vein located posterior to the third ventricle and pineal gland, draining into the straight sinus. - Its position is more posterior and inferior to the structure indicated by the red arrow. *Pineal gland* - The **pineal gland** is a small, endocrine gland located in the epithalamus, posterior to the third ventricle and often calcified, appearing bright on CT scans. - While it's in the general vicinity, the red arrow points anterior and superior to where the pineal gland would typically be visualized. *Falx cerebri* - The **falx cerebri** is a large, crescent-shaped fold of dura mater that dips into the longitudinal fissure between the cerebral hemispheres. - It would appear as a linear structure in the sagittal plane or as a midline divider in some axial cuts, distinct from the deep brain structure indicated by the arrow.
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