Sensory Integration — MCQs

10 questions

Moro's reflex persisting for more than 6 months indicates damage to which of the following lobes?

A female presents with loss of vision in the right halves of both eyes. Where is the lesion located in the optic pathway?

Arrange the following in the sequence of auditory pathway: 1. Cochlear nucleus 2. Spiral ganglion 3. Superior olivary nucleus 4. Inferior colliculus 5. Medial geniculate body

Area numbers for the somatosensory area include:

Impulses generated in the taste buds of the tongue reach the cerebral cortex via the

Which of the following is not seen in a hyperkinetic child?

Positive Romberg test with eyes closed detects a defect in -

All the following features are seen in neurons from dorsal root ganglia, EXCEPT:

Which of the following statements about hallucinations is true?

Q10

All of the following statements are true regarding cavernous sinus thrombosis EXCEPT:

Sensory Integration Indian Medical PG Practice Questions and MCQs

Question 1: Moro's reflex persisting for more than 6 months indicates damage to which of the following lobes?

A. Temporal
B. Frontal (Correct Answer)
C. Occipital
D. Parietal

Explanation: ***Frontal*** - Persistence of primitive reflexes such as the **Moro reflex** beyond 6 months suggests **delayed cortical maturation** and failure of cortical inhibition. - The **frontal lobe** and its connections via the **corticospinal tract** play a key role in suppressing brainstem-mediated primitive reflexes as the CNS matures. - While persistence often indicates **generalized CNS dysfunction** (e.g., cerebral palsy, developmental delay), among cortical lobes, the frontal lobe's motor and inhibitory functions make it most relevant to reflex suppression. *Temporal* - The temporal lobe is primarily involved in **auditory processing**, **memory formation**, and **language comprehension**. - Damage typically presents with **aphasia**, **auditory deficits**, or **memory impairment**, not persistent primitive reflexes. *Occipital* - The occipital lobe is responsible for **visual processing** and **visual perception**. - Lesions result in **visual field defects**, **cortical blindness**, or **visual agnosia**, not reflex abnormalities. *Parietal* - The parietal lobe integrates **sensory information** and is involved in **spatial awareness** and **body sensation**. - Damage leads to **sensory deficits**, **neglect syndromes**, or **apraxia**, not persistence of primitive reflexes.

Question 2: A female presents with loss of vision in the right halves of both eyes. Where is the lesion located in the optic pathway?

A. Left optic tract (Correct Answer)
B. Optic radiation
C. Optic chiasma
D. Right optic tract

Explanation: Left optic tract - A lesion in the **left optic tract** causes **right homonymous hemianopsia**, meaning loss of vision in the right halves of both eyes [1]. - This is because the left optic tract carries visual information from the **nasal retina of the right eye** and the **temporal retina of the left eye**, both of which process the right visual field [1]. *Optic radiation* - A lesion in the optic radiation would also cause a **homonymous hemianopsia** but depending on the specific location within the radiation, it could result in a **quadrantanopia** (loss of a quarter visual field) rather than a complete hemianopsia. - The optic radiation projects from the **lateral geniculate nucleus** to the **visual cortex**, and damage here affects the post-chiasmatic visual pathway [1]. *Optic chiasma* - A lesion at the **optic chiasma** typically results in **bitemporal hemianopsia**, which is the loss of vision in the **temporal halves of both eyes** [1]. - This occurs because the **crossing nasal fibers** from both eyes, which carry information from the temporal visual fields, are affected [1]. *Right optic tract* - A lesion in the **right optic tract** would result in **left homonymous hemianopsia**, meaning loss of vision in the **left halves of both eyes** [1]. - This is due to the right optic tract carrying fibers from the **nasal retina of the left eye** and the **temporal retina of the right eye**, both of which process the left visual field [1].

Question 3: Arrange the following in the sequence of auditory pathway: 1. Cochlear nucleus 2. Spiral ganglion 3. Superior olivary nucleus 4. Inferior colliculus 5. Medial geniculate body

A. 5-4-3-2-1
B. 3-4-5-1-2
C. 2-1-3-4-5 (Correct Answer)
D. 1-2-3-4-5

Explanation: ***2-1-3-4-5*** - The auditory pathway begins with the **spiral ganglion**, which contains the cell bodies of the first-order neurons that innervate the hair cells of the cochlea. - Signals then proceed to the **cochlear nucleus** in the brainstem, followed by the **superior olivary nucleus**, the **inferior colliculus**, and finally the **medial geniculate body** in the thalamus before reaching the auditory cortex [1]. *5-4-3-2-1* - This sequence represents a nearly reverse order of the ascending auditory pathway, starting from a higher processing center (medial geniculate body) and moving backward, which is incorrect for sensory input. - The **medial geniculate body** is the thalamic relay for auditory information, receiving input from lower centers and projecting to the auditory cortex [1]. *3-4-5-1-2* - This sequence incorrectly places the **superior olivary nucleus** as the initial processing stage, preceding the lower-level **spiral ganglion** and **cochlear nucleus**. - Auditory information must first be transduced by hair cells and then relayed by the spiral ganglion neurons to the cochlear nucleus before further processing in the olivary complex. *1-2-3-4-5* - This sequence incorrectly places the **cochlear nucleus** before the **spiral ganglion**. - The **spiral ganglion** contains the primary afferent neurons that receive input from the hair cells and project their axons to the cochlear nucleus.

Question 4: Area numbers for the somatosensory area include:

A. 5 & 7
B. 1, 2 & 3 (Correct Answer)
C. 4 & 6
D. 16 & 18

Explanation: ***1, 2 & 3*** - These Brodmann areas (1, 2, and 3) collectively represent the **primary somatosensory cortex**, located in the postcentral gyrus [1]. - This region is responsible for processing **tactile** and **proprioceptive information** from the body [1]. *5 & 7* - Brodmann areas 5 and 7 are part of the **posterior parietal cortex**, involved in **multimodal sensory association** and spatial awareness [1]. - While they process sensory information, they are considered **somatosensory association areas**, not the primary somatosensory cortex [1]. *4 & 6* - Brodmann area 4 is the **primary motor cortex**, responsible for initiating voluntary movements. - Brodmann area 6 is the **premotor and supplementary motor cortex**, involved in planning and coordinating movements [2]. *16 & 18* - Areas 16 and 18 are not associated with somatosensory function. - Brodmann area 18 is a **visual association area** (secondary visual cortex), involved in processing and interpreting visual information.

Question 5: Impulses generated in the taste buds of the tongue reach the cerebral cortex via the

A. Thalamus (Correct Answer)
B. Dorsal roots of the first cervical spinal nerve
C. Hypoglossal nerve
D. Lingual nerve

Explanation: ***Thalamus*** - The **thalamus** acts as a crucial relay station for almost all sensory information, including taste, before it reaches the **cerebral cortex** for conscious perception. - Taste signals from the cranial nerves (facial, glossopharyngeal, vagus) travel to the **nucleus of the solitary tract** in the brainstem, then to the **ventral posteromedial (VPM) nucleus of the thalamus**, and finally to the **gustatory cortex**. *Dorsal roots of the first cervical spinal nerve* - The dorsal roots of cervical spinal nerves are involved in transmitting **somatosensory information** (touch, pain, temperature, proprioception) from the neck and head region, not taste. - These nerves carry signals from the spinal cord to the brain, whereas taste pathways originate from cranial nerves in the head. *Hypoglossal nerve* - The **hypoglossal nerve (CN XII)** is primarily a **motor nerve** responsible for controlling the muscles of the tongue, essential for speech and swallowing. - It has no direct role in transmitting taste sensations to the cerebral cortex. *Lingual nerve* - The **lingual nerve** is a branch of the **trigeminal nerve (CN V)** and carries **general sensation** (touch, pain, temperature) from the anterior two-thirds of the tongue. - While it runs with the **chorda tympani** (a branch of the facial nerve that carries taste), the lingual nerve itself does not transmit taste signals to the brain.

Question 6: Which of the following is not seen in a hyperkinetic child?

A. Left-right disorientation (Correct Answer)
B. Decreased attention span
C. Aggressive outbursts
D. Soft neurological signs

Explanation: ***Left to right disorientation*** - **Left-right disorientation** is a sign of **developmental coordination disorder** or other specific learning difficulties, not a core symptom of hyperkinesis (ADHD). - Hyperkinetic children primarily exhibit symptoms related to **inattention**, **hyperactivity**, and **impulsivity**. *Decreased attention span* - A **decreased attention span** is a cardinal feature of **Attention-Deficit/Hyperactivity Disorder (ADHD)**, which is synonymous with hyperkinesis in children. - Children with ADHD often struggle with sustaining focus on tasks, leading to difficulties in academic and social settings. *Aggressive outbursts* - **Aggressive outbursts** and **irritability** can be associated features of hyperkinetic disorder, particularly in children who also experience **oppositional defiant disorder** or **conduct disorder** as comorbidities. - Impulsivity and difficulty with emotional regulation can contribute to these behaviors. *Soft neurological signs* - **Soft neurological signs** (e.g., poor coordination, minor motor deficits, abnormal reflexes) are more frequently observed in children with **hyperkinetic disorder** compared to neurotypical children. - These signs indicate subtle neurological dysfunction that is not localized or severe enough to be classified as a distinct neurological disorder.

Question 7: Positive Romberg test with eyes closed detects a defect in -

A. Cerebellum
B. Peripheral nerve
C. Proprioceptive pathway (Correct Answer)
D. Spinothalamic tract

Explanation: Proprioceptive pathway - A positive Romberg test indicates a loss of proprioception, meaning the patient cannot maintain balance when visual cues are removed, relying solely on somatosensory input [2]. - This suggests damage to the dorsal columns of the spinal cord or peripheral nerves that transmit proprioceptive information to the brain [1], [3]. Cerebellum - While cerebellar dysfunction also causes ataxia and balance problems, it would typically present as difficulty maintaining balance even with eyes open, referred to as cerebellar ataxia [2]. - A Romberg test primarily assesses the integrity of the proprioceptive system, distinguishing it from cerebellar issues where balance problems are evident regardless of visual input [2]. Peripheral nerve - Peripheral neuropathy can indeed lead to a positive Romberg test if the sensory nerves responsible for proprioception are affected [1]. - However, "Proprioceptive pathway" is a more direct and encompassing answer, as peripheral nerves are a component of this pathway, which also includes spinal cord tracts [3]. Spinothalamic tract - The spinothalamic tract primarily transmits sensations of pain and temperature, not proprioception [3]. - Damage to this tract would result in deficits in these specific sensory modalities, rather than a positive Romberg test [1].

Question 8: All the following features are seen in neurons from dorsal root ganglia, EXCEPT:

A. They are multipolar (Correct Answer)
B. They are derived from neural crest cells
C. They have eccentrically located nuclei
D. They contain lipofuscin granules

Explanation: ***They are multipolar*** - Dorsal root ganglia (DRG) neurons are typically **pseudounipolar**, meaning they have a single process that branches into two (peripheral and central) rather than multiple dendrites and an axon [1]. - **Multipolar neurons** are characteristic of motor neurons and interneurons in the central nervous system, not DRG sensory neurons [1]. *They contain lipofuscin granules* - **Lipofuscin granules** are common in long-lived, post-mitotic cells like neurons and are considered "wear and tear" pigments, accumulating with age. - Their presence in DRG neurons is a normal finding and reflects the neuron's metabolic activity over time. *They have eccentrically located nuclei* - While not universally present in all DRG neurons, an **eccentrically located nucleus** is a common histological feature of certain types of DRG neurons, particularly larger ones. - This feature helps distinguish them from other neuron types and can be accentuated by the large amount of cytoplasm in these cells. *They are derived from neural crest cells* - All sensory neurons of the DRG, along with other components like Schwann cells and sympathetic ganglia, originate from **neural crest cells**. - This developmental origin is a fundamental characteristic of DRG neurons, distinguishing them from CNS neurons derived from the neural tube.

Question 9: Which of the following statements about hallucinations is true?

A. There is misinterpretation of external stimulus
B. Can be controlled by voluntary effort
C. Perceived as real but without an external stimulus (Correct Answer)
D. Always indicates severe mental illness

Explanation: ***Perceived as real but without an external stimulus*** - Hallucinations are defined by the perception of sensory experiences (e.g., seeing, hearing, feeling) that **feel real to the individual** but have **no corresponding external stimulus**. - This fundamental characteristic distinguishes them from other perceptual distortions like illusions. *There is misinterpretation of external stimulus* - This describes an **illusion**, where an actual external stimulus is misinterpreted (e.g., seeing a coat in the dark and believing it's a person). - Hallucinations occur in the **absence of any external stimulus**, making this statement incorrect for defining hallucinations. *Can be controlled by voluntary effort* - Hallucinations, being involuntary sensory experiences, are generally **not amenable to conscious control** or suppression by the individual experiencing them. - The lack of voluntary control is a key feature distinguishing them from imagination or fantasy. *Always indicates severe mental illness* - While often associated with severe mental illnesses like **schizophrenia**, hallucinations can also occur due to various other causes, including **substance intoxication or withdrawal**, neurological conditions (e.g., delirium, Parkinson's disease), or even during periods of extreme fatigue or stress. - Therefore, stating they *always* indicate severe mental illness is inaccurate.

Question 10: All of the following statements are true regarding cavernous sinus thrombosis EXCEPT:

A. Loss of jaw jerk (Correct Answer)
B. Loss of sensation around the eye
C. Sphenoid sinusitis is the most common cause
D. Inferior ophthalmic vein can spread infection from dangerous area of face

Explanation: ***Loss of jaw jerk*** - The **jaw jerk reflex** is mediated by the **trigeminal nerve (V3)** and its mesencephalic nucleus, which lies within the brainstem, superior to the cavernous sinus. - Cavernous sinus thrombosis primarily affects structures passing *through* or *adjacent* to the sinus, predominantly **cranial nerves III, IV, V1, V2, and VI**, but typically does not directly impact the brainstem structures responsible for the jaw jerk reflex in its localized progression. *Inferior ophthalmic vein can spread infection from dangerous area of face* - The **inferior ophthalmic vein** drains into the **cavernous sinus**, providing a direct route for infection from the **"dangerous area" of the face** (e.g., upper lip, nose, medial canthus). - This venous connection allows pathogens to enter the cavernous sinus and cause **thrombosis**. *Sphenoid sinusitis is the most common cause* - **Sphenoid sinusitis** is a common cause of **cavernous sinus thrombosis** due to the close anatomical proximity of the sphenoid sinuses to the cavernous sinuses. - Inflammation and infection in the sphenoid sinus can easily spread directly into the adjacent cavernous sinus. *Loss of sensation around the eye* - The **ophthalmic division (V1)** of the trigeminal nerve passes through the **cavernous sinus** and provides sensation to the forehead, upper eyelid, and **area around the eye**. - Compression or involvement of V1 due to thrombosis can result in **sensory deficits** in this distribution.

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