Ignite Creation Date:
2024-05-05 @ 5:15 PM
Last Modification Date:
2024-10-26 @ 9:30 AM
Study NCT ID:
NCT00422071
Status:
COMPLETED
Last Update Posted:
2019-12-17
First Post:
2007-01-12
Brief Title:
Detecting a Reward Signal in the Motor Cortex
Sponsor:
National Institute of Neurological Disorders and Stroke NINDS
Organization:
National Institutes of Health Clinical Center CC
Study Overview
Official Title:
Detecting a Reward Signal in the Motor Cortex
Status:
COMPLETED
Status Verified Date:
2014-03-06
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
This study will use transcranial magnetic stimulation TMS to determine whether the activity in the brain when someone wins something affects the part of the brain that controls movement Studies have shown that the brain releases signals to mark rewards for certain behavior like the activity the brain generates when an animal receives food or drink after performing a certain action This study will look for a way to detect this kind of signal in humans
Healthy volunteers between 18 and 60 years of age are eligible for this study Participants undergo TMS during two experiments slot machine stimulation and key sequence see below For TMS a wire coil is held on the subject s scalp A brief electrical current is passed through the coil creating a magnetic pulse that stimulates the brain The stimulation may cause twitching in muscles of the face arm or leg and there may be a pulling sensation on the skin under the coil The effect of TMS on the muscles is detected with small metal disk electrodes taped onto the skin of the arms or legs
The stimulation strength needed to activate the hand muscles is determined at the beginning of each experiment To do this the subject sits with his or her arms and hand relaxed Magnetic pulses of varying strengths are applied in order to find the right strength Also a series of 45 pairs of magnetic pulses is administered so close to each other that they produce only one movement Measurements of the movements generated serve as a baseline for comparison with movements generated during the experiments
Slot Machine Simulation
Subjects play a computer game similar to a slot machine They press a button to start the game and watch as three barrels of the machine spin into place Subjects can win 025 1or 5 if all three barrels match when they stop spinning If all three barrels do not match subjects do not win any money except in rare instances when they are awarded money even when all three barrels do not match In one trial in this experiment subjects receive transcranial magnetic stimulation after they see the second barrel stop spinning In another trial they receive the stimulation after the third barrel stops spinning
Key Sequence
Subjects see a letter on a computer screen and press a combination of the three keyboard keys G H and J If they press the keys in the right order and under the time limit they win 1 At some point the letter displayed changes and the subjects must guess a new combination to earn money Each of the letters corresponds to its own combination of key presses A few moments after the subjects see whether they pressed the keys in the right order they receive TMS
Healthy volunteers between 18 and 60 years of age are eligible for this study Participants undergo TMS during two experiments slot machine stimulation and key sequence see below For TMS a wire coil is held on the subject s scalp A brief electrical current is passed through the coil creating a magnetic pulse that stimulates the brain The stimulation may cause twitching in muscles of the face arm or leg and there may be a pulling sensation on the skin under the coil The effect of TMS on the muscles is detected with small metal disk electrodes taped onto the skin of the arms or legs
The stimulation strength needed to activate the hand muscles is determined at the beginning of each experiment To do this the subject sits with his or her arms and hand relaxed Magnetic pulses of varying strengths are applied in order to find the right strength Also a series of 45 pairs of magnetic pulses is administered so close to each other that they produce only one movement Measurements of the movements generated serve as a baseline for comparison with movements generated during the experiments
Slot Machine Simulation
Subjects play a computer game similar to a slot machine They press a button to start the game and watch as three barrels of the machine spin into place Subjects can win 025 1or 5 if all three barrels match when they stop spinning If all three barrels do not match subjects do not win any money except in rare instances when they are awarded money even when all three barrels do not match In one trial in this experiment subjects receive transcranial magnetic stimulation after they see the second barrel stop spinning In another trial they receive the stimulation after the third barrel stops spinning
Key Sequence
Subjects see a letter on a computer screen and press a combination of the three keyboard keys G H and J If they press the keys in the right order and under the time limit they win 1 At some point the letter displayed changes and the subjects must guess a new combination to earn money Each of the letters corresponds to its own combination of key presses A few moments after the subjects see whether they pressed the keys in the right order they receive TMS
Detailed Description:
Objectvie
The role of mesencephalic dopamine neurons in reward processing has been established in primates using electrophysiological techniques and in humans using functional neuroimaging Their role is thought to be dual i they show sustained activity with the expectation of a future reward and ii a phasic response after reward Animal data indicate that these neurons located in the midbrain areas A8-10 behave as a single functional unit when activated They have rich projections to both the prefrontal and motor cortices where they synapse on interneurons and cortical pyramidal cells producing primarily inhibition Though their function is not fully understood these projections clearly play an important role in motivation and learning Since there are no electrophysiological techniques available to detect dopaminergic or inhibitory activity in the human prefrontal cortex our objective is to develop a paradigm to detect a reward related signal in the primary motor cortex where transcranial magnetic stimulation can be used to measure brief events
Study Population
The population that we will study will be healthy volunteers between the ages of 18-60 without any significant medical history contraindication to TMS or history of addictive behavior
Design
Our hypothesis is that the dopamine reward-related signal will alter level of evocable inhibition in primary motor cortex Using behavioral paradigms that deliver intermittent reward we aim to demonstrate a difference in the amount of cortical inhibition i when reward is expected compared to when reward is not expected ii after rewarded compared to unrewarded trials iii when reward follows a variable effortful response and iv when there is uncertainty as to whether a reward will be administered If we are unable to produce a signal in the motor cortex with these simple paradigms we will look for a reward-related change in inhibition when the rewarded behavior is the associative learning of a motor sequence We will control for effects of variations in attention related to the experimental task but not specific for reward with a similar behavioral paradigm that manipulates attention and expectation
Outcome Measures
The outcome measures will be changes in the conditionedunconditioned MEP for each reward condition
The role of mesencephalic dopamine neurons in reward processing has been established in primates using electrophysiological techniques and in humans using functional neuroimaging Their role is thought to be dual i they show sustained activity with the expectation of a future reward and ii a phasic response after reward Animal data indicate that these neurons located in the midbrain areas A8-10 behave as a single functional unit when activated They have rich projections to both the prefrontal and motor cortices where they synapse on interneurons and cortical pyramidal cells producing primarily inhibition Though their function is not fully understood these projections clearly play an important role in motivation and learning Since there are no electrophysiological techniques available to detect dopaminergic or inhibitory activity in the human prefrontal cortex our objective is to develop a paradigm to detect a reward related signal in the primary motor cortex where transcranial magnetic stimulation can be used to measure brief events
Study Population
The population that we will study will be healthy volunteers between the ages of 18-60 without any significant medical history contraindication to TMS or history of addictive behavior
Design
Our hypothesis is that the dopamine reward-related signal will alter level of evocable inhibition in primary motor cortex Using behavioral paradigms that deliver intermittent reward we aim to demonstrate a difference in the amount of cortical inhibition i when reward is expected compared to when reward is not expected ii after rewarded compared to unrewarded trials iii when reward follows a variable effortful response and iv when there is uncertainty as to whether a reward will be administered If we are unable to produce a signal in the motor cortex with these simple paradigms we will look for a reward-related change in inhibition when the rewarded behavior is the associative learning of a motor sequence We will control for effects of variations in attention related to the experimental task but not specific for reward with a similar behavioral paradigm that manipulates attention and expectation
Outcome Measures
The outcome measures will be changes in the conditionedunconditioned MEP for each reward condition
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None
Secondary IDs
| Secondary ID | Type | Domain | Link |
|---|---|---|---|
| 07-N-0063 | None | None | None |