Q.1 Which neuromodulation technique uses magnetic fields to induce electric currents in the brain?
Deep Brain Stimulation (DBS)
Transcranial Magnetic Stimulation (TMS)
Transcranial Direct Current Stimulation (tDCS)
Vagus Nerve Stimulation (VNS)
Explanation - TMS generates brief magnetic pulses that pass through the scalp and induce electric currents in cortical neurons, modulating their activity.
Correct answer is: Transcranial Magnetic Stimulation (TMS)
Q.2 What is the primary purpose of a pulse generator in a Deep Brain Stimulation (DBS) system?
To record neural activity
To deliver controlled electrical pulses to the brain
To amplify incoming EEG signals
To stimulate peripheral muscles
Explanation - The pulse generator (often implanted in the chest) creates programmable electrical pulses that travel through leads to specific brain targets.
Correct answer is: To deliver controlled electrical pulses to the brain
Q.3 Which of the following is a common clinical application of Vagus Nerve Stimulation (VNS)?
Parkinson's disease
Depression
Epilepsy
Essential tremor
Explanation - VNS was originally approved for refractory epilepsy and later for treatment‑resistant depression.
Correct answer is: Epilepsy
Q.4 In transcranial Direct Current Stimulation (tDCS), what does the anode generally do to neuronal excitability?
Decrease excitability
Increase excitability
No effect
Block action potentials
Explanation - Anodal tDCS typically depolarizes neuronal membranes, making neurons more likely to fire.
Correct answer is: Increase excitability
Q.5 Which parameter of DBS most directly influences the spatial extent of neural activation?
Pulse frequency
Pulse width
Amplitude (voltage/current)
Electrode material
Explanation - Higher amplitudes increase the electric field radius, recruiting more distant neurons.
Correct answer is: Amplitude (voltage/current)
Q.6 What is the typical frequency range used in high‑frequency DBS for Parkinson's disease?
1–10 Hz
20–50 Hz
130–185 Hz
250–300 Hz
Explanation - High‑frequency stimulation (≈130 Hz) suppresses pathological neuronal firing patterns in the subthalamic nucleus.
Correct answer is: 130–185 Hz
Q.7 Which neuromodulation technique can be used to selectively activate genetically modified neurons?
Deep Brain Stimulation
Optogenetics
Transcranial Magnetic Stimulation
Ultrasound Neuromodulation
Explanation - Optogenetics uses light‑sensitive ion channels expressed in targeted cells, allowing precise control with light.
Correct answer is: Optogenetics
Q.8 Focused ultrasound neuromodulation primarily interacts with neural tissue through which physical mechanism?
Magnetic induction
Electrical conduction
Mechanical displacement of membranes
Chemical diffusion
Explanation - Acoustic pressure waves cause micro‑displacements of cell membranes, altering ion channel activity.
Correct answer is: Mechanical displacement of membranes
Q.9 Which of the following best describes a ‘closed‑loop’ neuromodulation system?
A device that delivers stimulation at a fixed schedule regardless of brain state
A system that records neural signals and adjusts stimulation parameters in real time
A stimulator that can be turned on or off manually by a clinician
A device that only stimulates peripheral nerves
Explanation - Closed‑loop systems use feedback (e.g., LFPs) to adapt stimulation, improving efficacy and reducing side effects.
Correct answer is: A system that records neural signals and adjusts stimulation parameters in real time
Q.10 In the context of DBS electrode design, what does the term ‘contact spacing’ refer to?
Distance between the pulse generator and the lead
Separation between individual electrode contacts on a lead
Time interval between successive pulses
Electrical resistance of the lead material
Explanation - Contact spacing determines the size of the stimulated volume and the ability to shape the electric field.
Correct answer is: Separation between individual electrode contacts on a lead
Q.11 Which brain region is most commonly targeted by DBS for treating essential tremor?
Subthalamic nucleus
Globus pallidus internus
Ventral intermediate nucleus of the thalamus
Motor cortex
Explanation - The VIM nucleus is an effective target for tremor suppression via high‑frequency stimulation.
Correct answer is: Ventral intermediate nucleus of the thalamus
Q.12 What is the main advantage of using high‑impedance contacts in a DBS electrode?
Reduced power consumption
Higher spatial resolution of stimulation
Longer battery life
Simpler surgical implantation
Explanation - High‑impedance contacts confine current to a smaller area, allowing more precise targeting.
Correct answer is: Higher spatial resolution of stimulation
Q.13 During tDCS, a typical current intensity used in human studies is:
0.1 mA
1–2 mA
5–10 mA
20–30 mA
Explanation - Most tDCS protocols employ 1–2 mA for safe, tolerable stimulation lasting up to 30 minutes.
Correct answer is: 1–2 mA
Q.14 Which safety concern is most associated with high‑frequency TMS?
Skin burns
Induction of seizures
Hearing loss from coil noise
Electrode corrosion
Explanation - High‑frequency (>5 Hz) TMS can provoke seizures in susceptible individuals, requiring screening and monitoring.
Correct answer is: Induction of seizures
Q.15 The term ‘neuroplasticity’ in neuromodulation refers to:
The ability of electrodes to change shape
Long‑term changes in synaptic strength induced by stimulation
Plastic deformation of neural tissue
Variability in patient age
Explanation - Neuromodulation can promote synaptic remodeling, leading to lasting therapeutic effects beyond the stimulation period.
Correct answer is: Long‑term changes in synaptic strength induced by stimulation
Q.16 In an optogenetic experiment, which wavelength of light would you use to activate channelrhodopsin‑2 (ChR2)?
Red (≈ 660 nm)
Green (≈ 525 nm)
Blue (≈ 470 nm)
Infrared (≈ 900 nm)
Explanation - ChR2 is maximally sensitive to blue light around 470 nm, opening cation channels to depolarize neurons.
Correct answer is: Blue (≈ 470 nm)
Q.17 Which of the following biomarkers is often used as feedback in a closed‑loop DBS system for Parkinson’s disease?
Local field potentials (LFPs) in the beta band
Electroencephalogram (EEG) alpha rhythm
Heart rate variability
Blood oxygen saturation
Explanation - Beta‑band (13–30 Hz) LFPs correlate with motor symptoms and are commonly used to trigger adaptive DBS.
Correct answer is: Local field potentials (LFPs) in the beta band
Q.18 Which neuromodulation method is currently being explored for non‑invasive stimulation of deep brain structures using focused ultrasound?
Transcranial Direct Current Stimulation
Transcranial Magnetic Stimulation
Low‑Intensity Focused Ultrasound (LIFU)
Transcutaneous Electrical Nerve Stimulation
Explanation - LIFU can reach subcortical targets without surgery, offering a non‑invasive alternative to DBS.
Correct answer is: Low‑Intensity Focused Ultrasound (LIFU)
Q.19 What is the primary function of the ‘shunt’ resistor in a tDCS circuit?
To limit the maximum voltage
To divert excess current away from the scalp
To measure the applied current
To protect against short circuits
Explanation - A precision shunt resistor enables accurate current monitoring by producing a known voltage drop proportional to the current.
Correct answer is: To measure the applied current
Q.20 Which of the following statements about electrode impedance is TRUE?
Higher impedance always improves stimulation efficacy.
Impedance is independent of frequency.
Low impedance reduces voltage required for a given current.
Impedance does not affect battery life.
Explanation - According to Ohm’s law (V = I·R), lower impedance means less voltage is needed to deliver the same current, conserving battery power.
Correct answer is: Low impedance reduces voltage required for a given current.
Q.21 In DBS, what does the term ‘volume of tissue activated (VTA)’ describe?
Physical size of the implanted pulse generator
Region of the brain where neurons are sufficiently depolarized by the electric field
Amount of battery charge remaining
Length of the implanted lead
Explanation - VTA is a computational estimate of the tissue volume that experiences enough electric field strength to affect neuronal firing.
Correct answer is: Region of the brain where neurons are sufficiently depolarized by the electric field
Q.22 Which neuromodulation technique has FDA clearance for treating chronic migraine?
Transcranial Magnetic Stimulation (TMS)
Vagus Nerve Stimulation (VNS)
Transcranial Direct Current Stimulation (tDCS)
Deep Brain Stimulation (DBS)
Explanation - Single‑pulse TMS devices (e.g., FDA‑cleared for migraine) deliver brief pulses to the occipital cortex to abort migraine attacks.
Correct answer is: Transcranial Magnetic Stimulation (TMS)
Q.23 What is the main reason for using biphasic pulse waveforms in neural stimulation?
To increase the charge per phase
To reduce electrode corrosion and tissue damage
To double the stimulation frequency
To make the device louder
Explanation - Biphasic pulses balance charge, minimizing net DC and thus reducing electrochemical reactions that can damage tissue or electrodes.
Correct answer is: To reduce electrode corrosion and tissue damage
Q.24 Which of the following is a typical side effect of chronic high‑frequency DBS of the subthalamic nucleus?
Improved vision
Speech articulation problems
Hair loss
Increased appetite
Explanation - Stimulation near the subthalamic nucleus can affect neighboring pathways, occasionally leading to dysarthria.
Correct answer is: Speech articulation problems
Q.25 During a tDCS session, the electrodes are often referred to as 'anode' and 'cathode.' Which of the following statements is correct?
The cathode always delivers a higher current than the anode.
The anode is placed over the target cortical area to increase excitability.
The cathode is used only for recording EEG signals.
Both electrodes have the same polarity.
Explanation - Anodal stimulation tends to depolarize neurons, so the anode is positioned over the region intended for facilitation.
Correct answer is: The anode is placed over the target cortical area to increase excitability.
Q.26 Which of the following best describes 'interleaved stimulation' in DBS programming?
Alternating between two different pulse amplitudes on the same contact
Delivering stimulation to two separate contacts with different parameters in a time‑alternating fashion
Rapidly switching the device on and off every second
Combining electrical and magnetic stimulation simultaneously
Explanation - Interleaving allows clinicians to target two distinct brain regions or symptom domains without increasing total charge density.
Correct answer is: Delivering stimulation to two separate contacts with different parameters in a time‑alternating fashion
Q.27 What is the typical duration of a single magnetic pulse in standard repetitive TMS (rTMS) protocols?
10 µs
100 µs
1 ms
10 ms
Explanation - A standard TMS pulse lasts about 100 microseconds, delivering a rapid magnetic field change that induces an electric field in the cortex.
Correct answer is: 100 µs
Q.28 Which of these neuromodulation methods can be used to modulate peripheral nerves without direct surgical implantation?
Deep Brain Stimulation
Transcutaneous Electrical Nerve Stimulation (TENS)
Optogenetics
Intracortical Microstimulation
Explanation - TENS delivers electrical currents through the skin to stimulate peripheral nerves for pain relief.
Correct answer is: Transcutaneous Electrical Nerve Stimulation (TENS)
Q.29 Which material is most commonly used for the conductive part of chronic neural electrodes?
Gold
Silicon
Platinum‑Iridium alloy
Copper
Explanation - Pt‑Ir is biocompatible, corrosion‑resistant, and provides stable electrochemical properties for long‑term stimulation.
Correct answer is: Platinum‑Iridium alloy
Q.30 In a closed‑loop DBS system using beta‑band LFPs, what would likely happen when beta power rises above a preset threshold?
Stimulation amplitude is decreased
Stimulation is turned off
Stimulation amplitude is increased
Battery voltage is boosted
Explanation - Higher beta power is associated with motor rigidity; the system raises stimulation to suppress it.
Correct answer is: Stimulation amplitude is increased
Q.31 Which of the following best explains why high‑frequency (>100 Hz) stimulation often suppresses neuronal firing?
It causes neuronal hyperpolarization through potassium accumulation
It blocks the sodium channels via depolarization block
It heats the tissue, leading to temporary inactivation
It enhances neurotransmitter release
Explanation - Sustained high‑frequency depolarization can inactivate voltage‑gated Na⁺ channels, preventing action potentials.
Correct answer is: It blocks the sodium channels via depolarization block
Q.32 Which neuromodulation approach uses a small, implantable device that delivers stimulation to the dorsal root ganglion (DRG) for chronic pain relief?
Spinal Cord Stimulation (SCS)
Deep Brain Stimulation (DBS)
Dorsal Root Ganglion Stimulation (DRGS)
Transcranial Magnetic Stimulation (TMS)
Explanation - DRGS targets the DRG directly, providing focal pain control with fewer side effects compared to conventional SCS.
Correct answer is: Dorsal Root Ganglion Stimulation (DRGS)
Q.33 What is the primary reason for using a ‘ramp‑up’ period when initiating DBS therapy?
To allow the battery to charge fully
To gradually habituate neural tissue and reduce side effects
To synchronize with the patient’s circadian rhythm
To calibrate the device’s telemetry
Explanation - Slowly increasing amplitude helps the brain adapt, minimizing adverse events such as paresthesias.
Correct answer is: To gradually habituate neural tissue and reduce side effects
Q.34 Which of the following frequency ranges is typically used for inhibitory rTMS protocols?
1 Hz
5 Hz
10 Hz
20 Hz
Explanation - Low‑frequency (≈1 Hz) rTMS reduces cortical excitability, often used for conditions like epilepsy or depression.
Correct answer is: 1 Hz
Q.35 In neural recording, what does the term ‘signal‑to‑noise ratio (SNR)’ refer to?
The ratio of electrode size to lead length
The amplitude of the neural signal divided by the amplitude of background noise
The number of channels in a recording system
The battery life of the recording device
Explanation - Higher SNR indicates clearer recordings, essential for accurate feedback in closed‑loop neuromodulation.
Correct answer is: The amplitude of the neural signal divided by the amplitude of background noise
Q.36 Which of the following best describes the concept of ‘field shaping’ in DBS?
Changing the physical shape of the electrode lead
Adjusting pulse width to alter waveform shape
Programming multiple contacts to create a custom electric field distribution
Using magnetic fields to bend electrical currents
Explanation - Field shaping uses directional contacts and varying amplitudes to target specific neural structures while sparing others.
Correct answer is: Programming multiple contacts to create a custom electric field distribution
Q.37 Which of the following is a key limitation of optogenetics for clinical neuromodulation?
Inability to target specific cell types
Requirement for invasive light delivery
Lack of genetic tools for humans
All of the above
Explanation - Optogenetics needs gene delivery, light‑delivery hardware, and faces regulatory/ethical challenges for human use.
Correct answer is: All of the above
Q.38 In a tDCS montage designed to enhance working memory, which cortical area is most commonly targeted with the anode?
Occipital cortex
Pre‑frontal cortex (DLPFC)
Motor cortex
Somatosensory cortex
Explanation - Anodal tDCS over the dorsolateral prefrontal cortex has been shown to improve executive functions and working memory.
Correct answer is: Pre‑frontal cortex (DLPFC)
Q.39 Which neuromodulation technique relies on the principle of Faraday’s law of electromagnetic induction?
Deep Brain Stimulation
Transcranial Magnetic Stimulation
Transcranial Direct Current Stimulation
Vagus Nerve Stimulation
Explanation - TMS coils generate a time‑varying magnetic field that induces electric currents in the brain (Faraday’s law).
Correct answer is: Transcranial Magnetic Stimulation
Q.40 What does the term ‘cathodic first’ mean in the context of biphasic stimulation pulses?
The negative phase precedes the positive phase
The positive phase precedes the negative phase
Both phases have equal polarity
The pulse starts with a zero‑current interval
Explanation - ‘Cathodic first’ indicates that the initial phase drives electrons into the tissue (negative polarity), which is generally more effective at depolarizing neurons.
Correct answer is: The negative phase precedes the positive phase
Q.41 Which of the following is NOT a typical advantage of directional DBS leads over conventional cylindrical leads?
Ability to steer the electric field laterally
Reduced power consumption
Improved symptom control with fewer side effects
More precise targeting of asymmetric anatomy
Explanation - Directional leads provide better targeting but may require more complex programming; power consumption is similar or slightly higher due to additional contacts.
Correct answer is: Reduced power consumption
Q.42 Which of the following parameters is most directly related to the charge density delivered per pulse in neural stimulation?
Pulse frequency
Pulse width
Amplitude (current or voltage)
Electrode surface area
Explanation - Charge per phase = current × pulse width; charge density further divides by electrode area, but amplitude (current) is the primary determinant.
Correct answer is: Amplitude (current or voltage)
Q.43 In the context of neuromodulation safety, what does the acronym ‘MRI‑compatible’ mean for an implanted device?
The device can be used to acquire MRI images of the brain.
The device will not be heated, displaced, or malfunction during an MRI scan.
The device can replace the MRI scanner.
The device can only be used in low‑field MRI systems.
Explanation - MRI‑compatible implants are designed to avoid ferromagnetic attraction, excessive heating, and interference with image acquisition.
Correct answer is: The device will not be heated, displaced, or malfunction during an MRI scan.
Q.44 Which neuromodulation technique is most often employed intra‑operatively to map functional cortical areas during brain surgery?
Deep Brain Stimulation
Transcranial Magnetic Stimulation
Cortical Direct Electrical Stimulation
Transcranial Direct Current Stimulation
Explanation - Surgeons apply low‑current pulses directly to exposed cortex to identify eloquent regions (e.g., motor, language) before resection.
Correct answer is: Cortical Direct Electrical Stimulation
Q.45 Which of the following best describes ‘neuroprosthesis’ in the field of neuromodulation?
A drug that enhances synaptic transmission
A device that replaces or augments lost neural function through electrical stimulation
A surgical technique to remove damaged brain tissue
A computational model of neural networks
Explanation - Neuroprostheses, such as cochlear implants or motor cortex stimulators, restore function by delivering patterned electrical signals.
Correct answer is: A device that replaces or augments lost neural function through electrical stimulation
Q.46 During a standard rTMS session for depression, how long does a typical treatment course last?
One single session
5–6 weeks with daily sessions
3 months with weekly sessions
1 year with monthly sessions
Explanation - Clinical protocols usually involve daily (weekday) sessions over 4–6 weeks to achieve therapeutic effects.
Correct answer is: 5–6 weeks with daily sessions
Q.47 Which of the following is a primary advantage of using a rechargeable DBS battery over a non‑rechargeable one?
Smaller device size
Unlimited lifespan
Reduced frequency of surgical replacements
Higher stimulation amplitudes
Explanation - Rechargeable batteries can last many years, decreasing the need for replacement surgeries.
Correct answer is: Reduced frequency of surgical replacements
Q.48 What is the main physiological effect of stimulating the nucleus accumbens with DBS in treatment‑resistant depression?
Inhibition of motor pathways
Modulation of reward circuitry to improve mood
Direct activation of visual cortex
Suppression of auditory processing
Explanation - The nucleus accumbens is a key node in the brain’s reward system; DBS here can alleviate depressive symptoms.
Correct answer is: Modulation of reward circuitry to improve mood
Q.49 In the context of neuromodulation, the term ‘phase‑locked stimulation’ refers to:
Stimulation delivered at a fixed frequency regardless of neural activity
Stimuli synchronized to a specific phase of an ongoing neural oscillation
Stimulation that changes polarity every millisecond
A method of powering the implant wirelessly
Explanation - Phase‑locked stimulation can enhance or suppress targeted rhythms by timing pulses to the oscillation’s phase.
Correct answer is: Stimuli synchronized to a specific phase of an ongoing neural oscillation
Q.50 Which of the following is a commonly used metric for evaluating the effectiveness of a closed‑loop DBS system in Parkinson’s disease?
Unified Parkinson’s Disease Rating Scale (UPDRS) motor scores
Blood glucose levels
Heart rate variability
Visual acuity test
Explanation - UPDRS motor subscale is a standard clinical outcome measure for motor symptom improvement.
Correct answer is: Unified Parkinson’s Disease Rating Scale (UPDRS) motor scores
Q.51 Which neuromodulation technique is based on delivering low‑intensity ultrasound bursts to modulate neuronal activity without breaking the blood‑brain barrier?
Transcranial Magnetic Stimulation
Low‑Intensity Focused Ultrasound (LIFU)
Transcranial Direct Current Stimulation
Vagus Nerve Stimulation
Explanation - LIFU can safely modulate neural excitability by mechanical effects, without thermal damage or BBB disruption at low intensities.
Correct answer is: Low‑Intensity Focused Ultrasound (LIFU)
Q.52 What is the main purpose of a ‘sham’ condition in a neuromodulation clinical trial?
To test the durability of the device
To provide a placebo control that mimics the sensation of stimulation without therapeutic effect
To calibrate the device’s output
To increase the sample size
Explanation - Sham stimulation helps differentiate true physiological effects from expectancy or placebo effects.
Correct answer is: To provide a placebo control that mimics the sensation of stimulation without therapeutic effect
Q.53 Which of the following best describes the relationship between pulse width and selectivity for activating axons versus cell bodies?
Longer pulse widths preferentially activate cell bodies
Shorter pulse widths preferentially activate axons
Pulse width has no effect on selectivity
Longer pulse widths preferentially activate axons
Explanation - Axons have lower chronaxie; thus, brief pulses are more efficient at stimulating them than longer pulses that recruit somata.
Correct answer is: Shorter pulse widths preferentially activate axons
Q.54 In the design of a neural electrode, why is the surface area often roughened or coated with materials like iridium oxide?
To increase mechanical strength
To reduce impedance and increase charge injection capacity
To make the electrode visible on X‑ray
To change the color of the implant
Explanation - Roughened surfaces provide a larger effective area, lowering impedance and allowing higher safe charge densities.
Correct answer is: To reduce impedance and increase charge injection capacity
Q.55 Which of the following clinical conditions has NOT yet received FDA approval for DBS therapy?
Essential tremor
Obsessive‑compulsive disorder (OCD)
Alzheimer’s disease
Parkinson’s disease
Explanation - DBS for Alzheimer's remains investigational; the other three have FDA clearance for specific indications.
Correct answer is: Alzheimer’s disease
Q.56 What does the term ‘current steering’ refer to in directional DBS systems?
Changing the direction of current flow between multiple contacts to shape the electric field
Physically rotating the electrode after implantation
Altering the polarity of the pulse generator
Using magnetic fields to redirect current
Explanation - Current steering distributes current among segmented contacts, enabling precise targeting of asymmetric neural structures.
Correct answer is: Changing the direction of current flow between multiple contacts to shape the electric field
Q.57 Which of the following is a commonly reported side effect of chronic VNS therapy?
Hoarseness or voice changes
Hair loss
Increased visual acuity
Weight gain
Explanation - Stimulation of the recurrent laryngeal nerve can cause hoarseness, coughing, or throat discomfort.
Correct answer is: Hoarseness or voice changes
Q.58 During an intra‑operative cortical mapping session, which frequency of stimulation is typically used to elicit motor responses?
1 Hz
20 Hz
50 Hz
100 Hz
Explanation - Low‑frequency (≈50 Hz) biphasic pulses reliably evoke motor evoked potentials without causing tissue damage.
Correct answer is: 50 Hz
Q.59 Which neuromodulation technique utilizes an implanted electrode cuff around the vagus nerve in the neck?
Deep Brain Stimulation
Vagus Nerve Stimulation
Spinal Cord Stimulation
Transcranial Direct Current Stimulation
Explanation - VNS cuff electrodes encircle the cervical vagus nerve to deliver intermittent electrical pulses.
Correct answer is: Vagus Nerve Stimulation
Q.60 Which of the following best explains why high‑frequency DBS can improve tremor while low‑frequency stimulation may worsen it?
High frequency blocks abnormal oscillatory activity; low frequency reinforces it
High frequency heats the tissue, reducing tremor
Low frequency depletes neurotransmitters
High frequency increases blood flow
Explanation - High‑frequency stimulation disrupts pathological synchrony, whereas low‑frequency can entrain the same rhythm, worsening symptoms.
Correct answer is: High frequency blocks abnormal oscillatory activity; low frequency reinforces it
Q.61 In neuromodulation, the term ‘chronaxie’ refers to:
The time interval between two consecutive pulses
The minimum pulse width required to excite a neuron at twice the rheobase current
The latency of a motor evoked potential
The duration of the battery life
Explanation - Chronaxie is a tissue‑specific parameter describing excitability; it helps optimize pulse width settings.
Correct answer is: The minimum pulse width required to excite a neuron at twice the rheobase current
Q.62 Which of the following statements about transcranial alternating current stimulation (tACS) is true?
tACS delivers direct current that does not change over time
tACS can entrain endogenous brain rhythms by delivering sinusoidal currents
tACS is only used for peripheral nerve stimulation
tACS requires surgical implantation
Explanation - tACS applies weak alternating currents at specific frequencies to modulate oscillatory activity.
Correct answer is: tACS can entrain endogenous brain rhythms by delivering sinusoidal currents
Q.63 Which parameter is most critical to avoid tissue damage during electrical stimulation?
Pulse frequency
Charge density per phase
Stimulation polarity
Device manufacturer
Explanation - Exceeding safe charge density limits can cause irreversible electrochemical reactions and tissue injury.
Correct answer is: Charge density per phase
Q.64 In a DBS system, what is the purpose of the ‘telemetry’ feature?
To deliver stimulation pulses
To wirelessly transmit device diagnostics and programming data to an external programmer
To record EEG signals
To charge the battery inductively
Explanation - Telemetry enables clinicians to adjust settings and monitor battery status without opening the patient’s skin.
Correct answer is: To wirelessly transmit device diagnostics and programming data to an external programmer
Q.65 Which neuromodulation method is most suitable for delivering highly focal stimulation to a specific cortical column?
Transcranial Magnetic Stimulation
Deep Brain Stimulation
Intracortical Microstimulation
Transcranial Direct Current Stimulation
Explanation - Microelectrodes placed within cortex can stimulate a single column (~100 µm) with high spatial precision.
Correct answer is: Intracortical Microstimulation
Q.66 Which of the following is a major challenge when using optogenetics in large‑animal models?
Insufficient light penetration depth
Lack of suitable viral vectors
Excessive heat generation
All of the above
Explanation - Large brains require deeper light delivery, efficient gene transfer, and careful thermal management, making translation difficult.
Correct answer is: All of the above
Q.67 In the context of neuromodulation research, what does the abbreviation ‘ECoG’ stand for?
Electroencephalography
Epidural cortical galvanometry
Electrocorticography
External cardiac gating
Explanation - ECoG records electrical activity directly from the cortical surface, providing high spatial resolution for feedback in closed‑loop systems.
Correct answer is: Electrocorticography
Q.68 Which of the following best characterizes ‘temporal interference stimulation’?
Using two high‑frequency electric fields that interfere to create a low‑frequency envelope in deep tissue
Applying alternating magnetic fields at multiple frequencies
Delivering pulses with varying pulse widths
Combining ultrasound with electrical stimulation
Explanation - Temporal interference creates a beat frequency that can selectively stimulate deep neurons while sparing superficial tissue.
Correct answer is: Using two high‑frequency electric fields that interfere to create a low‑frequency envelope in deep tissue
Q.69 What is the main reason that DBS leads are often coated with silicone rather than metal alone?
Silicone is more conductive
Silicone provides biocompatibility and flexibility, reducing tissue damage
Silicone makes the lead visible on MRI
Silicone increases the electrical resistance for better stimulation
Explanation - Silicone encapsulation protects surrounding tissue, allows the lead to flex with brain movement, and limits scar formation.
Correct answer is: Silicone provides biocompatibility and flexibility, reducing tissue damage
Q.70 Which of the following is a key advantage of using a rechargeable battery with inductive charging for an implanted neurostimulator?
Eliminates need for any external hardware
Allows continuous stimulation without battery drain
Enables wireless power transfer through the skin, avoiding repeated surgeries
Provides unlimited power output
Explanation - Inductive charging allows the patient to recharge the implant transcutaneously, extending device lifespan without surgical replacements.
Correct answer is: Enables wireless power transfer through the skin, avoiding repeated surgeries
Q.71 In neuromodulation, the term ‘synchronization’ generally refers to:
Aligning the timing of stimulation pulses with the patient’s heartbeat
Coordinated firing of neuronal populations at a specific frequency
Matching the device’s clock with a computer
Standardizing electrode manufacturing processes
Explanation - Synchronization of neural oscillations underlies many cognitive processes and pathological states; neuromodulation can enhance or disrupt it.
Correct answer is: Coordinated firing of neuronal populations at a specific frequency
Q.72 Which of the following neuromodulation methods is most often used to treat overactive bladder?
Deep Brain Stimulation
Sacral Nerve Stimulation
Transcranial Direct Current Stimulation
Vagus Nerve Stimulation
Explanation - Sacral nerve stimulators target sacral nerves (S3) to modulate bladder control pathways.
Correct answer is: Sacral Nerve Stimulation
Q.73 What is the typical pulse width range used in clinical DBS settings?
10–30 µs
60–120 µs
200–400 µs
500–800 µs
Explanation - Clinically, pulse widths between 60 and 120 µs balance efficacy and charge density limits.
Correct answer is: 60–120 µs
Q.74 Which of the following best describes ‘neurofeedback’ in the context of non‑invasive neuromodulation?
Using implanted electrodes to record brain activity
Providing real‑time visual or auditory feedback to the user based on their own brain signals to facilitate self‑regulation
Delivering high‑frequency magnetic pulses
Adjusting battery voltage automatically
Explanation - Neurofeedback trains subjects to modulate their own neural activity, often using EEG or fNIRS as the feedback source.
Correct answer is: Providing real‑time visual or auditory feedback to the user based on their own brain signals to facilitate self‑regulation
Q.75 Which of the following is NOT a typical component of a neuromodulation system?
Implantable pulse generator
Electrode leads
External power supply (for implanted devices)
Telemetry programmer
Explanation - Implanted devices are self‑contained (battery or rechargeable) and do not rely on an external power source during operation.
Correct answer is: External power supply (for implanted devices)
Q.76 In the context of DBS for movement disorders, what does the acronym ‘STN’ stand for?
Superior Temporal Nucleus
Subthalamic Nucleus
Spinal Trigeminal Nerve
Sensory Thalamic Node
Explanation - The STN is a common DBS target for Parkinson’s disease, helping to alleviate motor symptoms.
Correct answer is: Subthalamic Nucleus
Q.77 Which safety guideline recommends a maximum charge density of 30 µC/cm² per phase for chronic neural stimulation?
FDA Guidance for Neuromodulation Devices
International Electrotechnical Commission (IEC) 60601‑1‑10
Institute of Electrical and Electronics Engineers (IEEE) Standard 11073
World Health Organization (WHO) Noise Standards
Explanation - IEC 60601‑1‑10 sets safety limits for charge density to prevent tissue damage during chronic stimulation.
Correct answer is: International Electrotechnical Commission (IEC) 60601‑1‑10
Q.78 What is the primary therapeutic goal of using spinal cord stimulation (SCS) for chronic pain?
To block all sensory input from the body
To generate motor responses that mask pain
To activate the dorsal column pathways, producing paresthesias that mask pain signals
To increase blood flow to the spinal cord
Explanation - SCS induces a tingling sensation that competes with pain signals, reducing perceived pain intensity.
Correct answer is: To activate the dorsal column pathways, producing paresthesias that mask pain signals
Q.79 Which of the following is a major advantage of using a “leadless” neurostimulator (e.g., subdermal device) over traditional lead‑based systems?
Higher stimulation amplitudes
Elimination of lead‑related infection risk
Ability to stimulate deeper brain structures
Simpler programming interface
Explanation - Leadless devices avoid percutaneous leads, reducing infection and hardware complications.
Correct answer is: Elimination of lead‑related infection risk
Q.80 In a typical tACS protocol aimed at enhancing alpha rhythm (≈10 Hz), what is the likely effect on participants’ visual attention?
Improved visual detection
Reduced visual attention
No change in visual performance
Induced visual hallucinations
Explanation - Alpha‑frequency tACS can increase cortical inhibition, often leading to decreased visual attention performance.
Correct answer is: Reduced visual attention
Q.81 Which neuromodulation technique is currently being explored for restoring movement in spinal cord injury patients by stimulating the spinal cord circuitry?
Deep Brain Stimulation
Spinal Cord Stimulation (SCS)
Vagus Nerve Stimulation
Transcranial Magnetic Stimulation
Explanation - Epidural SCS can activate locomotor circuits, enabling voluntary movement in some paralyzed patients.
Correct answer is: Spinal Cord Stimulation (SCS)
Q.82 Which of the following best defines the term ‘neuromodulatory plasticity’?
Permanent structural changes in the skull due to implants
Short‑term changes in neuronal excitability that persist after stimulation
Long‑lasting alterations in synaptic strength induced by patterned stimulation
Growth of new blood vessels around the electrode
Explanation - Neuromodulatory plasticity refers to durable changes in connectivity, such as LTP/LTD, following specific stimulation protocols.
Correct answer is: Long‑lasting alterations in synaptic strength induced by patterned stimulation
Q.83 Which of the following is a primary reason for using bipolar stimulation configuration instead of monopolar in cortical implants?
Bipolar configuration reduces stimulation intensity needed
Bipolar configuration creates a more confined electric field, limiting spread to adjacent tissue
Bipolar configuration extends battery life
Bipolar configuration eliminates the need for a ground electrode
Explanation - Bipolar stimulation confines the field between two contacts, improving spatial selectivity and reducing off‑target effects.
Correct answer is: Bipolar configuration creates a more confined electric field, limiting spread to adjacent tissue
Q.84 In a closed‑loop DBS system, which signal is most commonly used as the feedback trigger for adaptive stimulation in essential tremor?
Beta‑band LFPs
Tremor‑related EMG activity
Heart rate variability
Respiratory rhythm
Explanation - Peripheral EMG can detect tremor onset, allowing the system to increase stimulation only when needed.
Correct answer is: Tremor‑related EMG activity
Q.85 Which of the following best describes the effect of increasing the pulse frequency from 10 Hz to 100 Hz in a tDCS protocol?
It converts tDCS into tACS
It has no effect; tDCS is independent of frequency
It increases the total charge delivered per unit time
It reduces the polarity of the stimulation
Explanation - Higher pulse frequency means more pulses per second, delivering more charge, which can affect safety and efficacy.
Correct answer is: It increases the total charge delivered per unit time
Q.86 Which of the following statements about ‘electrode impedance spectroscopy’ is correct?
It measures the magnetic field strength of the electrode
It determines the frequency‑dependent impedance to assess electrode–tissue interface health
It records neural spikes directly
It calibrates the battery voltage
Explanation - Impedance spectroscopy provides information about the capacitive and resistive properties of the electrode–tissue interface, useful for monitoring degradation.
Correct answer is: It determines the frequency‑dependent impedance to assess electrode–tissue interface health
Q.87 Which of the following is the most common method for delivering chronic stimulation to the peripheral vagus nerve?
Transcranial Magnetic Stimulation
Implanted cuff electrode with an implanted pulse generator
Surface electrode pads on the neck
Intravenous drug infusion
Explanation - Chronic VNS uses a cuff wrapped around the cervical vagus nerve connected to an implanted generator.
Correct answer is: Implanted cuff electrode with an implanted pulse generator
Q.88 Which of the following best explains why high‑resolution MRI is often required before DBS surgery?
To visualize the exact location of blood vessels and target nuclei
To measure the patient’s brain temperature
To assess the electrical conductivity of skull bone
To calibrate the surgical robot
Explanation - High‑resolution MRI provides anatomical detail needed for precise targeting while avoiding vascular injury.
Correct answer is: To visualize the exact location of blood vessels and target nuclei
Q.89 In neuromodulation, the term ‘burst stimulation’ typically refers to:
A single high‑amplitude pulse
A rapid series of pulses grouped together, separated by longer pauses
Continuous sinusoidal stimulation
A stimulation pattern that mimics heartbeats
Explanation - Burst paradigms can mimic natural firing patterns and have been shown to improve certain therapeutic outcomes.
Correct answer is: A rapid series of pulses grouped together, separated by longer pauses
Q.90 Which of the following is a primary limitation of using TMS for deep brain targets like the subthalamic nucleus?
Insufficient magnetic field strength to reach deep structures
Excessive heating of the coil
Inability to generate electric fields
Requirement of surgical implantation
Explanation - Standard TMS coils have limited depth penetration; deep targets require specialized coils or alternative methods.
Correct answer is: Insufficient magnetic field strength to reach deep structures
Q.91 Which of the following best describes ‘neurovascular coupling’ in the context of neuromodulation?
The relationship between neural activity and local blood flow changes
The electrical connection between neurons and blood vessels
The mechanical bonding of electrodes to the vasculature
The use of blood‑based biomarkers to guide stimulation
Explanation - Neurovascular coupling is the basis for functional imaging (fMRI) and influences safety considerations during stimulation.
Correct answer is: The relationship between neural activity and local blood flow changes
Q.92 Which of the following is a key feature of a ‘multipolar’ DBS lead?
Only one active contact
Multiple independent contacts that can be programmed simultaneously
Built‑in battery for independent operation
Wireless power transmission
Explanation - Multipolar leads allow flexible shaping of the electric field by activating different contact combinations.
Correct answer is: Multiple independent contacts that can be programmed simultaneously
Q.93 In neuromodulation research, the term ‘dose‑response curve’ refers to:
The relationship between stimulation parameters (e.g., amplitude) and therapeutic effect
The battery life of the device over time
The number of patients enrolled in a clinical trial
The frequency of device software updates
Explanation - A dose‑response curve helps identify the minimal effective stimulation intensity while minimizing side effects.
Correct answer is: The relationship between stimulation parameters (e.g., amplitude) and therapeutic effect
Q.94 Which of the following statements about the safety of transcranial Direct Current Stimulation (tDCS) is correct?
tDCS can cause permanent brain lesions if used above 5 mA
tDCS is considered safe up to 2 mA for sessions up to 30 minutes in healthy adults
tDCS always requires surgical implantation
tDCS is contraindicated in all patients with metal implants
Explanation - Current guidelines indicate that 1–2 mA for ≤30 min is well tolerated with minimal adverse effects.
Correct answer is: tDCS is considered safe up to 2 mA for sessions up to 30 minutes in healthy adults
Q.95 Which of the following best describes ‘field‑shaping’ using segmented DBS leads?
Changing the shape of the lead tip
Programming different amplitudes on segmented contacts to steer the electric field
Altering the pulse waveform to a triangular shape
Using a larger battery to increase voltage
Explanation - Segmented contacts enable directional stimulation, allowing clinicians to focus the field toward target tissue while avoiding side‑effects.
Correct answer is: Programming different amplitudes on segmented contacts to steer the electric field
Q.96 What is the main advantage of using ‘high‑density’ electrode arrays for cortical stimulation?
Lower manufacturing cost
Higher spatial resolution, enabling selective activation of small cortical columns
Longer battery life
Reduced need for surgical implantation
Explanation - High‑density arrays contain many closely spaced contacts, allowing precise targeting of fine cortical structures.
Correct answer is: Higher spatial resolution, enabling selective activation of small cortical columns
Q.97 Which neuromodulation technique is most commonly used to treat chronic refractory neuropathic pain by targeting the dorsal column of the spinal cord?
Deep Brain Stimulation
Spinal Cord Stimulation
Transcranial Magnetic Stimulation
Vagus Nerve Stimulation
Explanation - SCS delivers low‑frequency pulses to dorsal columns, creating paresthesias that mask neuropathic pain.
Correct answer is: Spinal Cord Stimulation
Q.98 In an optogenetic experiment, which type of light‑sensitive protein would you use to silence neuronal activity?
Channelrhodopsin‑2 (ChR2)
Halorhodopsin (NpHR)
Archaerhodopsin (Arch)
Both B and C
Explanation - Halorhodopsin and archaerhodopsin are inhibitory opsins that hyperpolarize neurons when illuminated.
Correct answer is: Both B and C
Q.99 Which of the following best explains why chronic DBS leads can cause gliosis around the electrode tip?
Electrical current heats the tissue, causing scarring
Mechanical insertion trauma initiates a foreign‑body response
High‑frequency stimulation directly stimulates glial cells
Battery depletion leads to inflammation
Explanation - Implantation damages tissue and triggers glial proliferation, forming a gliotic sheath that can increase impedance over time.
Correct answer is: Mechanical insertion trauma initiates a foreign‑body response
Q.100 Which of the following is a primary goal of using ‘adaptive’ or ‘closed‑loop’ neuromodulation for essential tremor?
To eliminate the need for any programming
To automatically increase stimulation only when tremor is detected, conserving battery life
To stimulate the entire brain simultaneously
To replace the pulse generator with a smartphone
Explanation - Adaptive systems sense tremor (e.g., via accelerometers) and deliver stimulation only as needed, improving efficiency and reducing side effects.
Correct answer is: To automatically increase stimulation only when tremor is detected, conserving battery life
Q.101 Which of the following neuromodulation methods can be delivered completely non‑invasively, without any implanted hardware?
Deep Brain Stimulation
Transcranial Magnetic Stimulation
Spinal Cord Stimulation
Vagus Nerve Stimulation
Explanation - TMS uses an external coil to generate magnetic fields that induce currents in the brain without surgery.
Correct answer is: Transcranial Magnetic Stimulation
Q.102 What is the typical pulse shape used in most clinical DBS devices?
Square biphasic pulse
Sinusoidal pulse
Triangular monophasic pulse
Exponential decay pulse
Explanation - Square biphasic pulses provide a well‑defined charge per phase and reduce net DC offset.
Correct answer is: Square biphasic pulse
Q.103 Which of the following is a commonly used metric to assess the efficacy of DBS in Parkinson’s disease?
Timed Up and Go (TUG) test
Mini‑Mental State Examination (MMSE)
Beck Depression Inventory (BDI)
Visual Analogue Scale for Pain
Explanation - TUG assesses gait and balance improvements after DBS, providing an objective functional measure.
Correct answer is: Timed Up and Go (TUG) test
Q.104 Which of the following best describes the principle of ‘neuromodulatory entrainment’?
Synchronizing neural oscillations to an external rhythm
Increasing the number of neurons in a region
Generating new synaptic connections
Blocking all neural activity
Explanation - Entrainment aligns endogenous brain rhythms with the frequency of the applied stimulation, influencing cognition or motor control.
Correct answer is: Synchronizing neural oscillations to an external rhythm
Q.105 Which of the following is NOT a typical component of a research‑grade neuromodulation platform?
Programmable stimulus generator
High‑resolution neural recorder
Real‑time signal processing unit
Integrated MRI scanner
Explanation - Research platforms combine stimulation, recording, and processing; MRI scanners are separate imaging devices.
Correct answer is: Integrated MRI scanner
Q.106 In neuromodulation safety standards, what does the term ‘electrochemical safety window’ refer to?
The range of voltages where water electrolysis does not occur, preventing harmful by‑products
The time interval between successive pulses
The temperature range of the implant
The frequency band used for stimulation
Explanation - Staying within the electrochemical safety window (≈−0.6 V to +0.8 V vs. Ag/AgCl) avoids irreversible reactions and tissue damage.
Correct answer is: The range of voltages where water electrolysis does not occur, preventing harmful by‑products
Q.107 Which of the following neuromodulation techniques is most suitable for studying causal relationships between specific brain oscillations and behavior in a laboratory setting?
Deep Brain Stimulation
Transcranial Direct Current Stimulation
Transcranial Magnetic Stimulation
Vagus Nerve Stimulation
Explanation - TMS can transiently perturb cortical oscillations with precise timing, allowing causal inference in cognitive experiments.
Correct answer is: Transcranial Magnetic Stimulation
Q.108 What does the abbreviation ‘DBS’ stand for in neuroengineering?
Dynamic Brain Scanning
Deep Brain Stimulation
Digital Bioelectric System
Distributed Battery System
Explanation - DBS is a surgical neuromodulation technique that delivers electrical pulses to specific deep brain nuclei.
Correct answer is: Deep Brain Stimulation
Q.109 Which of the following is a common method for reducing the power consumption of an implanted neurostimulator?
Increasing pulse frequency
Using a higher impedance electrode
Implementing duty‑cycling (intermittent stimulation)
Operating at higher voltage
Explanation - Duty‑cycling reduces overall energy usage by delivering stimulation only when needed, extending battery life.
Correct answer is: Implementing duty‑cycling (intermittent stimulation)