Brain and Neuroanatomy Practice Questions

Q: Which of the following arteries does not supply the medulla?

Posterior cerebral artery. ***Posterior cerebral artery*** - The **posterior cerebral artery** primarily supplies the **occipital lobe**, the inferior and medial temporal lobes, and parts of the diencephalon and midbrain, not the medulla. - Its territory is typically superior to the medulla's vascular supply. *Basilar artery* - The **basilar artery** is formed by the union of the vertebral arteries and gives rise to several branches that supply the brainstem, including the pons and parts of the medulla. - Branches like the **anterior inferior cerebellar artery (AICA)** and **superior cerebellar artery (SCA)** can have anastomoses that contribute to medullary supply. *Anterior spinal artery* - The **anterior spinal artery**, formed from branches of the vertebral arteries, supplies the anterior two-thirds of the spinal cord and extends rostrally to supply a significant portion of the **medial medulla**. - It is crucial for supplying motor pathways and vital centers in the medulla. *Vertebral artery* - The **vertebral arteries** directly supply the medulla through their branches, including the **posterior inferior cerebellar artery (PICA)** and direct medullary branches. - They also give rise to the anterior and posterior spinal arteries which contribute to medullary supply.

Q: Blood supply of putamen includes all except?

Posterior communicating artery. ***Posterior communicating artery*** - The **posterior communicating artery** primarily supplies parts of the **thalamus**, **hypothalamus**, and **midbrain**, but not the putamen. - Its main role is to form part of the **Circle of Willis**, connecting the anterior and posterior cerebral circulations. *Medial striate arteries* - The **medial striate arteries** (or recurrent artery of Heubner) contribute to the blood supply of the **anteromedial part of the globus pallidus** and the **anterior limb of the internal capsule**, as well as parts of the putamen. - They are branches of the **anterior cerebral artery**. *Lateral striate arteries* - The **lateral striate arteries** [1] are crucial for supplying the **putamen**, **globus pallidus**, and the **posterior limb of the internal capsule**. - These arteries are predominantly branches of the **middle cerebral artery**. *Anterior choroidal artery* - The **anterior choroidal artery** supplies the **globus pallidus**, substantial portions of the **internal capsule**, and also contributes to the blood supply of the **posterolateral part of the putamen**. - It arises from the **internal carotid artery**.

Q: Identify the marked structure in the image.

Cerebellum. ***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.

Q: A 65-year-old lady presents with a vascular injury to the inferior frontal gyrus. Which functional area would be most affected?

Motor speech. ***Motor speech*** - The **inferior frontal gyrus** is home to **Broca's area**, which is critically involved in **motor speech production** [1]. - A vascular injury here would lead to **expressive aphasia**, where the ability to produce coherent speech is impaired despite intact comprehension [1]. *Visual* - The **visual cortex** is primarily located in the **occipital lobe**, which is at the posterior part of the brain, not the frontal gyrus. - Damage to this area would affect vision, potentially causing **hemianopia** or **cortical blindness**. *Auditory* - The **auditory cortex** is found in the **temporal lobe**, specifically the **superior temporal gyrus** [1]. - Injury to this region would impair the processing of sounds and potentially lead to forms of **auditory agnosia** [2]. *Wernicke* - **Wernicke's area**, responsible for **language comprehension**, is typically located in the **posterior part of the superior temporal gyrus**, in the temporal lobe [1]. - Damage to Wernicke's area results in **receptive aphasia**, where speech comprehension is affected, but speech production remains fluent though often nonsensical [1].

Q: Identify the structure marked by a red arrow in the image.

Fornix. ***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.

Q: Identify the type of the fibre marked in the image of the internal capsule.

Projection fibers. ***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.

Q: Where is the auditory cortex primarily located in the brain?

Superior temporal gyrus. ***Superior temporal gyrus*** - The **primary auditory cortex** (Brodmann areas 41 and 42) is located in the **superior temporal gyrus**, primarily within the **transverse temporal gyri of Heschl**. [1] - This region is responsible for processing **auditory information**, including pitch, loudness, and sound localization. [1] *Inferior temporal gyrus* - The **inferior temporal gyrus** is a part of the temporal lobe involved in higher-level **visual processing** and object recognition. - It plays a role in the "what" pathway of vision and **memory formation**, not primary auditory processing. *Area 3,1,2* - **Brodmann areas 3, 1, and 2** collectively form the **primary somatosensory cortex**. [2] - This area is located in the **postcentral gyrus** of the parietal lobe and is responsible for processing touch, pain, temperature, and proprioception. [2] *Cingulate gyrus* - The **cingulate gyrus** is a component of the **limbic system**, involved in emotion formation, learning, memory, and executive function. - It plays a role in processing emotional aspects of pain and fear, but not primary auditory perception.

Q: Which Brodmann's area is primarily associated with motor speech?

Area 44. Area 44 - **Brodmann Area 44** is primarily known as **Broca's area**, which is critical for **motor speech production** and language processing [1]. - Damage to this area typically results in **Broca's aphasia**, characterized by non-fluent speech and difficulty forming complete sentences [1]. Area 1, 2, 3 - These Brodmann areas constitute the **primary somatosensory cortex**, responsible for processing **tactile and proprioceptive information** from the body. - They are involved in sensory perception, not directly with motor speech production. Area 4, 6 - **Brodmann Area 4** is the **primary motor cortex**, involved in executing voluntary movements [2]. **Brodmann Area 6** is the **premotor and supplementary motor cortex**, involved in planning and coordinating movements [2]. - While these areas are crucial for motor control, they are not specifically associated as the primary center for motor speech in the same way Broca's area is. Area 40 - **Brodmann Area 40**, also known as the **supramarginal gyrus**, is part of the **parietal lobe** and is involved in phonological processing, language perception, and spatial cognition. - While it plays a role in language, it is not the primary area for motor speech production.

Q: Which nucleus is not seen in floor of the 4th ventricle -

Facial nucleus. Facial nucleus - The facial nucleus is located in the pontine tegmentum, anterior and ventrolateral to the abducens nucleus, and its fibers loop around the abducens nucleus forming the facial colliculus within the floor of the fourth ventricle, but the nucleus itself is not directly in the floor. - The nucleus's motor neurons originate deeper within the brainstem, not superficially in the floor. Abducens nucleus - The abducens nucleus is directly located in the floor of the fourth ventricle, beneath the facial colliculus. - Its neurons are responsible for innervating the lateral rectus muscle of the eye. Dorsal vagal nucleus - The dorsal vagal nucleus is situated in the floor of the fourth ventricle in the medulla, specifically in the vagal trigone. - It is responsible for the parasympathetic innervation of organs below the neck. Hypoglossal nucleus - The hypoglossal nucleus is located in the floor of the fourth ventricle, forming the hypoglossal trigone in the medulla. - It contains motor neurons that innervate the intrinsic and extrinsic muscles of the tongue.

Q: Which tract is responsible for the ventral tegmental decussation in the cerebral peduncle?

Rubrospinal tract. The rubrospinal tract originates in the red nucleus and decussates in the ventral tegmental decussation at the level of the midbrain, before descending to the spinal cord. This decussation is the characteristic feature that distinguishes it from other descending tracts. It primarily modulates flexor muscle tone and fine motor control of distal limb muscles. The tectospinal tract originates in the superior colliculus and decussates immediately as the dorsal tegmental decussation, involved in coordinating head and eye movements in response to stimuli. The vestibulospinal tract originates in the vestibular nuclei and descends ipsilaterally and contralaterally [1], but it does not form a distinct ventral tegmental decussation in the cerebral peduncle. It is crucial for maintaining posture and balance by influencing extensor muscles [1]. The tectobulbar tract arises from the superior colliculus and projects to cranial nerve nuclei, but it does not undergo the specific ventral tegmental decussation.

Question 1

Which of the following arteries does not supply the medulla?

Accepted Answer

Posterior cerebral artery

Answer

Basilar artery

Answer

Anterior spinal artery

Answer

Vertebral artery

Question 2

Blood supply of putamen includes all except?

Accepted Answer

Posterior communicating artery

Answer

Lateral striate arteries

Answer

Anterior choroidal artery

Answer

Medial striate arteries

Question 3

Identify the marked structure in the image.

Accepted Answer

Cerebellum

Answer

Cerebrum

Answer

Brain stem

Answer

Corpus callosum

Question 4

A 65-year-old lady presents with a vascular injury to the inferior frontal gyrus. Which functional area would be most affected?

Accepted Answer

Motor speech

Answer

Visual

Answer

Wernicke

Answer

Auditory

Question 5

Identify the structure marked by a red arrow in the image.

Accepted Answer

Fornix

Answer

Great vein of Galen

Answer

Pineal gland

Answer

Falx cerebri

Question 6

Identify the type of the fibre marked in the image of the internal capsule.

Accepted Answer

Projection fibers

Answer

Short association fibers

Answer

Long association fibers

Answer

Commissural fibers

Question 7

Where is the auditory cortex primarily located in the brain?

Accepted Answer

Superior temporal gyrus

Answer

Inferior temporal gyrus

Answer

Area 3,1,2

Answer

Cingulate gyrus

Question 8

Which Brodmann's area is primarily associated with motor speech?

Accepted Answer

Area 44

Answer

Area 1, 2, 3

Answer

Area 4, 6

Answer

Area 40

Question 9

Which nucleus is not seen in floor of the 4th ventricle -

Accepted Answer

Facial nucleus

Answer

Dorsal vagal nucleus

Answer

Hypoglossal nucleus

Answer

Abducens nucleus

Question 10

Which tract is responsible for the ventral tegmental decussation in the cerebral peduncle?

Accepted Answer

Rubrospinal tract

Answer

Tectospinal tract

Answer

Vestibulospinal tract

Answer

Tectobulbar tract

Brain and Neuroanatomy — MCQs

Brain and Neuroanatomy — MCQs

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