Neurophysiology Practice Questions

Q: Pruning is:

Programmed elimination during development. ***Programmed elimination during development*** - **Pruning** refers to the **programmed elimination** of excess **synapses** and **neurons** in the developing brain. - This process sculpts neural circuits, making them more efficient and specialized for cognitive functions. *Programmed elimination during irradiation* - **Irradiation** typically causes **cell damage** and death through mechanisms like **DNA damage**, which is not considered pruning. - While it can lead to programmed cell death (apoptosis), it is an exogenous injury, not a physiological developmental process. *Programmed elimination during cancer* - **Cancer** involves uncontrolled cell growth and often resistance to programmed cell death, rather than programmed elimination. - While some cancer treatments aim to induce cell death (e.g., apoptosis), this is a therapeutic intervention, not pruning. *Programmed elimination during senility* - **Senility** (aging) is associated with **neurodegeneration** and neuronal loss, but this is generally considered pathology or age-related decline, not pruning. - Pruning is a precisely timed and regulated developmental process, distinct from the stochastic and generally deleterious processes of aging.

Q: What is the normal intracranial pressure in a child (in mmH2O)?

50-80 mm of H2O. ***50-80 mm of H2O*** - This range represents the normal **intracranial pressure (ICP)** values for children. - While exact reference ranges can vary slightly between sources, this option falls within the generally accepted normal limits for a child. *30-70 mm of H2O* - This range is typically considered normal for **infants**, who have more compliant skulls and lower baseline ICP. - It is often too low for an older child, especially once the **fontanelles** have closed. *50-150 mm of H2O* - The upper end of this range (above 80 mmH2O) would indicate **elevated ICP** in children. - While the lower end is normal, the broadness makes it less precise for normal physiologic ICP. *100-150 mm of H2O* - This range clearly indicates **elevated intracranial pressure** in a child, necessitating immediate clinical evaluation and intervention. - Normal ICP in children is significantly lower than these values.

Q: Spinothalamic tract carries ?

Pain and temperature. ***Pain and temperature*** - The **spinothalamic tract** is primarily responsible for transmitting **pain** and **temperature** sensations to the brain. - This pathway decusates (crosses over) at the level of the spinal cord, meaning sensory information from one side of the body is processed by the contralateral brain. *Two-point discrimination* - This sensory modality is primarily carried by the **dorsal column-medial lemniscus pathway**, not the spinothalamic tract. - It involves the ability to distinguish two separate points of touch on the skin. *Kinesthesia* - **Kinesthesia**, the sense of movement, is also a function of the **dorsal column-medial lemniscus pathway**. - It allows awareness of body and limb position without visual input. *Proprioception* - **Proprioception**, the sense of joint position and limb orientation in space, is mediated by the **dorsal column-medial lemniscus pathway**. - This pathway is crucial for coordinated movement and balance.

Q: Wave II in BERA originates from ?

Proximal eighth nerve. ***Proximal eighth nerve*** - **Wave II** of the **Brainstem Auditory Evoked Response (BAER)**, or BERA, is generated by the **proximal portion of the auditory (eighth cranial) nerve** as it enters the brainstem. - This wave reflects the electrical activity of the auditory nerve fibers just before they synapse in the cochlear nucleus. *Cochlear nucleus* - The **cochlear nucleus** is primarily associated with the generation of **Wave III** of the BERA, following the auditory nerve activity. - It's the first synapse in the central auditory pathway, processing signals from the auditory nerve. *Distal eighth nerve* - The **distal portion of the eighth cranial nerve** is where **Wave I** of the BERA originates, representing the initial compound action potential from the auditory nerve as it exits the cochlea. - This wave reflects the activity closest to the cochlea, preceding the more central brainstem responses. *Lateral lemniscus* - The **lateral lemniscus** is a major ascending auditory pathway in the brainstem, and its activity contributes to later waves, specifically **Wave V or VI**, which are generated from the more rostral brainstem structures. - It plays a role in transmitting auditory information from the cochlear nuclei and superior olivary complex to the inferior colliculus.

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.

Question 1

Pruning is:

Accepted Answer

Programmed elimination during development

Answer

Programmed elimination during irradiation

Answer

Programmed elimination during cancer

Answer

Programmed elimination during senility

Question 2

What is the normal intracranial pressure in a child (in mmH2O)?

Accepted Answer

50-80 mm of H2O

Answer

30-70 mm of H2O

Answer

50-150 mm of H2O

Answer

100-150 mm of H2O

Question 3

Spinothalamic tract carries ?

Accepted Answer

Pain and temperature

Answer

Two point discrimination

Answer

Kinesthesia

Answer

Proprioception

Question 4

Wave II in BERA originates from ?

Accepted Answer

Proximal eighth nerve

Answer

Cochlear nucleus

Answer

Distal eighth nerve

Answer

Lateral lemniscus

Question 5

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 6

Sweat glands receive cholinergic innervation from

Accepted Answer

Post ganglionic sympathetic

Answer

Pre-ganglionic parasympathetic

Answer

Post ganglionic parasympathetic

Answer

Preganglionic sympathetic

Question 7

Fine touch and position sense is carried by

Accepted Answer

Dorsal column

Answer

Lateral spinothalamic tract

Answer

Anterior spinothalamic tract

Answer

Spinocerebellar tract

Question 8

Pain and temperature are carried by:

Accepted Answer

Lateral spinothalamic tract

Answer

Dorsal column pathway

Answer

Anterior spinothalamic tract

Answer

Ventral column pathway

Question 9

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

Accepted Answer

Allodynia

Answer

Causalgia

Answer

Hyperpathia

Answer

Hyperalgesia

Question 10

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

Accepted Answer

Superior colliculus

Answer

Pretectal nucleus

Answer

Frontal eye field

Answer

Area 17

Neurophysiology — MCQs

Neurophysiology — MCQs

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