Neurophysiology Practice Questions

Q: Aphasia is most likely associated with a lesion in

Broca's area. ***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]

Q: Sweat glands receive cholinergic innervation from

Post ganglionic sympathetic. ***Post ganglionic sympathetic*** - Sweat glands are one of the few exceptions where the **postganglionic sympathetic neurons** release **acetylcholine** (cholinergic innervation) instead of norepinephrine. - This specialized innervation stimulates increased sweat production for **thermoregulation**. *Pre-ganglionic parasympathetic* - Pre-ganglionic parasympathetic fibers release acetylcholine, but they synapse with post-ganglionic neurons in **ganglia located near or within target organs**, not directly innervating sweat glands. - Their primary role is in **rest-and-digest functions**, not sweat production. *Post ganglionic parasympathetic* - Post-ganglionic parasympathetic fibers typically innervate **smooth muscles and glands** in organs like the gut or bladder, releasing acetylcholine to promote relaxation or secretion. - They do not innervate sweat glands; sudoriferous glands fall under the sympathetic division for their innervation. *Preganglionic sympathetic* - Pre-ganglionic sympathetic neurons originate in the **thoracolumbar spinal cord** and release acetylcholine at the ganglia. - They do not directly innervate sweat glands; they synapse with **post-ganglionic sympathetic neurons** first.

Q: Fine touch and position sense is carried by

Dorsal column. ***Dorsal column*** - The **dorsal column-medial lemniscus pathway** is responsible for transmitting **fine touch**, **vibration**, **proprioception**, and **two-point discrimination** from the body to the brain. - This pathway includes the **fasciculus gracilis** (lower body) and **fasciculus cuneatus** (upper body) in the spinal cord. *Lateral spinothalamic tract* - The **lateral spinothalamic tract** primarily transmits sensations of **pain** and **temperature**. - It decussates (crosses) at the level of entry in the spinal cord and ascends contralaterally. *Anterior spinothalamic tract* - The **anterior spinothalamic tract** carries information about **crude touch** and **pressure**. - Like the lateral spinothalamic tract, it decussates at the spinal cord level and ascends contralaterally. *Spinocerebellar tract* - The **spinocerebellar tracts** (anterior and posterior) convey unconscious **proprioceptive** information to the **cerebellum**. - This information helps in coordinating muscle movements and maintaining posture, but it does not carry conscious fine touch or position sense.

Q: Pain and temperature are carried by:

Lateral spinothalamic tract. ***Lateral spinothalamic tract*** - The **lateral spinothalamic tract** is primarily responsible for transmitting **pain** and **temperature** sensations from the body to the brain. - This pathway decussates (crosses) at the level of the spinal cord segment where the sensory neuron enters, then ascends contralaterally. *Dorsal column pathway* - The **dorsal column pathway** (also known as the posterior column-medial lemniscus pathway) is responsible for **fine touch, vibration, and proprioception**. - It ascends ipsilaterally in the spinal cord and decussates in the medulla oblongata. *Anterior spinothalamic tract* - The **anterior spinothalamic tract** primarily carries information related to **crude touch** and **pressure**. - While part of the spinothalamic system, it does not carry pain and temperature as its primary function. *Ventral column pathway* - The term **ventral column pathway** is not a standard, precise neuroanatomical classification for a specific sensory tract. - While parts of the spinothalamic tracts (anterior and lateral) are located in the ventral/anterior funiculus of the spinal cord, "ventral column pathway" itself is not a primary sensory pathway.

Q: Perception of normal (non-painful) sensory stimuli as painful is called

Allodynia. ***Allodynia*** - This is the experience of **pain from stimuli that are not typically painful**, such as light touch or brushing against the skin. - It arises from abnormal processing of sensory signals in the central nervous system, often seen in conditions like **neuropathic pain** and **fibromyalgia**. *Causalgia* - This term refers to **complex regional pain syndrome type II**, which is characterized by **burning pain** and often involves nerve injury. - While it involves severe pain, it typically results from a noxious stimulus becoming excessively painful, rather than a non-painful stimulus being perceived as painful. *Hyperpathia* - This describes an **exaggerated pain reaction to a painful stimulus**, often involving a raised threshold for pain alongside an increased and persistent response. - Unlike allodynia, the initial stimulus is already painful; hyperpathia simply makes the response more intense and prolonged. *Hyperalgesia* - This is an **increased pain response to a stimulus that is normally painful**, meaning a painful stimulus is perceived as even more painful than expected. - The key difference from allodynia is that the stimulus itself is already nociceptive (pain-producing), whereas in allodynia, a non-nociceptive stimulus elicits pain.

Q: The structure that integrates impulses for eye-hand coordination is:

Superior colliculus. ***Superior colliculus*** - The **superior colliculus** is a crucial midbrain structure that plays a significant role in integrating visual, auditory, and somatosensory information to direct **saccadic eye movements** and orienting behaviors. - Its output projects to motor centers, facilitating **eye-hand coordination** by linking visual targets with appropriate motor responses. *Pretectal nucleus* - The **pretectal nucleus** is primarily involved in mediating the **pupillary light reflex**, controlling pupil constriction in response to light. - While it processes visual information, its main function is not direct eye-hand coordination. *Frontal eye field* - The **frontal eye field** is a part of the cerebral cortex involved in the voluntary control of eye movements, particularly **saccades**. - It plans and initiates eye movements but does not directly integrate sensory input for eye-hand coordination in the same way the superior colliculus does. *Area 17* - **Area 17**, also known as the **primary visual cortex (V1)**, is responsible for the initial processing of visual information, including detecting edges, orientations, and colors. - It is foundational for vision but does not directly integrate multimodal sensory input for coordinating eye and hand movements.

Q: Dorsal column lesions are associated with loss of:

Loss of proprioception. ***Proprioception*** - The **dorsal column-medial lemniscus pathway** is responsible for transmitting fine touch, vibration, and **proprioception** from the body to the brain. - Damage to this pathway, such as in a **dorsal column lesion**, directly impairs the ability to sense the position and movement of body parts. *Loss of ankle jerk reflex* - The **ankle jerk reflex**primarily tests the integrity of the **S1 and S2 nerve roots** and the reflex arc involving the gastrocnemius and soleus muscles. - This reflex is generally not directly affected by isolated dorsal column lesions, as it is a **deep tendon reflex** that relies on sensory and motor neuron pathways distinct from the dorsal column. *Loss of superficial abdominal reflexes* - **Superficial abdominal reflexes** assess the integrity of the T7-T12 spinal cord segments and corresponding nerve pathways. - These reflexes involve different neurological pathways compared to the dorsal column, which is primarily sensory for conscious proprioception, vibration, and fine touch. *Loss of knee jerk reflex* - The **knee jerk reflex** (patellar reflex) tests the integrity of the **L2, L3, and L4 spinal nerve roots** and the quadriceps femoris muscle. - Like the ankle jerk, this is a **deep tendon reflex** whose arc is separate from the dorsal column's ascending sensory tracts.

Q: Which of the following statements is MOST accurate regarding REM sleep?

Low muscle tone. ***Low muscle tone*** - **Muscle atonia** (near-complete loss of skeletal muscle tone) is one of the **defining physiological characteristics** of **REM sleep**. - This **muscle paralysis** prevents individuals from acting out their dreams and is a consistent, measurable feature of REM sleep. - Along with rapid eye movements and desynchronized EEG, **muscle atonia** is one of the three hallmark features that define REM sleep. *Dreams* - While **vivid dreams** are commonly associated with **REM sleep** and dream recall is highest during this stage, not all REM periods result in recalled dreams. - Dream recall varies significantly between individuals and circumstances. - Dreams can also occur during **NREM sleep**, though they are typically less vivid and less frequently recalled. *Slow waves on EEG* - **Slow waves** are characteristic of **deep non-REM sleep (N3 stage)**, not REM sleep. - During REM sleep, the **EEG** shows a **low-voltage, mixed-frequency pattern** resembling wakefulness (desynchronized EEG). *Decrease in BP* - During **REM sleep**, blood pressure often **fluctuates** and can even **increase** due to autonomic instability, rather than consistently decreasing. - The cardiovascular system exhibits **irregularities** in both heart rate and blood pressure during REM sleep.

Q: Complete transection of the spinal cord at the C7 level produces all of the following effects except:

Areflexia below the level of the lesion. ***Areflexia below the level of the lesion*** - While immediate **spinal shock** after a complete transection would cause areflexia, over time, the segments below the lesion often develop **hyperreflexia** and spasticity due to the loss of descending inhibitory control. - Therefore, sustained areflexia is an *unlikely* long-term effect of a complete spinal cord transection at C7. *Limited respiratory effort* - A C7 lesion would affect the **intercostal muscles** (innervated by T1-T11) and the **abdominal muscles** (innervated by T7-L1), which are crucial for forceful exhalation and coughing. - While the diaphragm (C3-C5) would be spared, breathing would still be significantly compromised, leading to a limited respiratory effort. *Anesthesia below the level of the lesion* - Complete transection interrupts all ascending sensory pathways, including the **spinothalamic tracts** (pain and temperature) and the **dorsal columns** (fine touch, vibration, proprioception), resulting in a complete loss of sensation below the C7 dermatome. - This is a hallmark of a complete spinal cord injury. *Hypotension* - Complete transection at C7 would disrupt the **sympathetic nervous system** pathways originating in the thoracolumbar region (T1-L2). - This leads to a loss of sympathetic tone to blood vessels, causing **vasodilation** and subsequent neurogenic shock, characterized by severe hypotension and bradycardia.

Q: Which of the following is true regarding cerebrospinal fluid?

Is actively secreted by choroid plexus. **Is actively secreted by choroid plexus** - **Cerebrospinal fluid (CSF)** is primarily produced by the **choroid plexus** via a combination of active transport and ultrafiltration processes. - The epithelial cells of the **choroid plexus** actively secrete ions and water, contributing to the formation and composition of CSF. *Virtually glucose free* - CSF normally contains **glucose**, although its concentration is about two-thirds of the plasma glucose concentration. - Significant reduction or absence of glucose in CSF often indicates a pathological process, such as **bacterial meningitis**. *Has the same pH of arterial blood* - The pH of CSF is typically slightly lower than that of arterial blood, usually around **7.31-7.34**, compared to plasma pH of 7.35-7.45. - This difference is crucial for maintaining the delicate acid-base balance within the central nervous system. *It is a major source of brain nutrition* - While CSF provides some nutrients, the primary source of brain nutrition is the **blood supply** through the cerebral vasculature. - Its main roles include providing **buoyancy**, **protection**, and acting as a medium for metabolite exchange, rather than direct substantial nutrition.

Question 1

Aphasia is most likely associated with a lesion in

Accepted Answer

Broca's area

Answer

Primary motor area

Answer

Sensory area

Answer

Visual area

Question 2

Sweat glands receive cholinergic innervation from

Accepted Answer

Post ganglionic sympathetic

Answer

Pre-ganglionic parasympathetic

Answer

Post ganglionic parasympathetic

Answer

Preganglionic sympathetic

Question 3

Fine touch and position sense is carried by

Accepted Answer

Dorsal column

Answer

Lateral spinothalamic tract

Answer

Anterior spinothalamic tract

Answer

Spinocerebellar tract

Question 4

Pain and temperature are carried by:

Accepted Answer

Lateral spinothalamic tract

Answer

Dorsal column pathway

Answer

Anterior spinothalamic tract

Answer

Ventral column pathway

Question 5

Perception of normal (non-painful) sensory stimuli as painful is called

Accepted Answer

Allodynia

Answer

Causalgia

Answer

Hyperpathia

Answer

Hyperalgesia

Question 6

The structure that integrates impulses for eye-hand coordination is:

Accepted Answer

Superior colliculus

Answer

Pretectal nucleus

Answer

Frontal eye field

Answer

Area 17

Question 7

Dorsal column lesions are associated with loss of:

Accepted Answer

Loss of proprioception

Answer

Loss of ankle jerk reflex

Answer

Loss of superficial abdominal reflexes

Answer

Loss of knee jerk reflex

Question 8

Which of the following statements is MOST accurate regarding REM sleep?

Accepted Answer

Low muscle tone

Answer

Slow waves on EEG

Answer

Decrease in BP

Answer

Dreams

Question 9

Complete transection of the spinal cord at the C7 level produces all of the following effects except:

Accepted Answer

Areflexia below the level of the lesion

Answer

Limited respiratory effort

Answer

Anesthesia below the level of the lesion

Answer

Hypotension

Question 10

Which of the following is true regarding cerebrospinal fluid?

Accepted Answer

Is actively secreted by choroid plexus

Answer

Virtually glucose free

Answer

Has the same pH of arterial blood

Answer

It is a major source of brain nutrition

Neurophysiology — MCQs

Neurophysiology — MCQs

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