Modulerende Cognitie Met behulp van transcraniële Direct Current Stimulatie van de kleine hersenen

The overall aim of this procedure is to demonstrate a technique for modulating cognition using transcranial direct current stimulation of the cerebellum. This is accomplished by first measuring performance during cognitive tasks of varying difficulty that each require the function of the cerebellum. The second step is to apply anodal, cathodal, or sham transcranial direct current stimulation over the cerebellum for 20 minutes in three separate groups of participants or in the same group separated by one week.

Next, measure performance again on all tasks after the application of cerebellar transcranial direct current stimulation. The final step is to process and analyze the data from each task and compare performance pre and post cerebellar TDCS. Ultimately, cathode or transcranial direct current stimulation over the cerebellum is used to show how cognitive functions can be facilitated when tasks are difficult rather than easy.

The implications of this technique extend towards therapy or diagnosis of cognitive e motor impairments because it has the potential to excite or depress neural activity, heightening or dampening certain behaviors, helping to demonstrate the procedure will be briney, a research associate from the laboratory. After welcoming the participant, ask them to read the information sheet and complete the TDCS safety questionnaire. If there are no contraindications to performing TDCS, then ask the participant to sign the consent form During this procedure.

Perform the calculation and language tasks one after the other in suit, a random order before and after the stimulation period in a quiet room to reduce distractions and permit accurate recording of auditory response times. Sit the participant in front of the computer screen and explain to them that they're going to perform an addition task and that they are going to hear a series of numbers through the headset, and that they will be required to add the number they just heard to the number immediately before it, and then vocalize the answer and continue to add the number they hear to the one immediately before it and not give a running total. Ensure that the participant is comfortable.

Position the microphone in front of the participant's mouth and ask them to read the instructions on the screen, which formally explain how to perform the paste auditory serial edition task. Once the participant has confirmed that they understand the task and will vocalize only the answer to the addition task. Perform a practice task, ask during the practice session.

Begin the presentation of numbers, increasing the presentation rate of the auditory items by reducing the inter stimulus interval by 300 milliseconds. After every block of five items between the interval range of 4.2 to 1.8 seconds, ensure that the stimuli are audible so that the investigator can follow the task for scoring purposes. Run through all of the 45 items that constitute the practice session.

Note the presentation rate that caused the participant to make three consecutive errors and use the rate proceeding this cutoff point during the task after the practice session has ended, set the presentation rate for the participant and ensure that this rate is maintained between the pre stimulation session and the post stimulation session. To begin the task again, ensure that the participant is seated comfortably and that the stimulus and responses are audible. Begin the task and present the 60 items at the appropriate rate.

During the task, write down each answer on the printed score sheet for subsequent verification. Give no score if the participant provides an incorrect answer or fails to respond and mark each correct answer. In turn, tell participants that the instructions for the subtraction task are the same as for the addition task, except this time they're required to subtract the number they just heard from the number immediately before it vocalize the answer, and then continue to subtract the number they hear from the one immediately before it.Again.

Make sure that the microphone has not moved away from the participant's mouth and have them read the instructions presented to them on the computer screen. After confirming that the participant understands the instructions and reminding them not to perform calculations orally or with the aid of the fingers, perform the practice task to determine the presentation rate. As before.

Begin the paste auditory, serial subtraction task and record answers on the printed score sheet as before. For this part of the experiment, first, explain to the participant that they have to say an appropriate verb in response to the presented noun. Clarify this noun verb relationship to participants at the beginning of the task.

Present the words centrally on the computer screen in a different random order in blocks, one to five consisting of repeated words, and in block six, consisting of novel words. The word lists in session one and two should be different and counterbalanced between participants. Start the task and ask the participant to read the standard instructions that are presented on the computer screen, which formally explains how to perform the verb generation task.

Once the participant has fully understood the task, position the microphone in front of the mouth and instruct them to produce words as soon as they appear on the computer screen. Make sure each word is replaced by the next word. When the microphone detects a response, write down or record each answer spoken aloud by the participant for subsequent verification.

Make a note of any errors or missed responses. Present words in the same manner as in the verb generation. Task participants Read nouns in the noun reading task and verbs in the verb reading task.

For both reading tasks, ensure the position of the microphone has not moved from the participant's mouth. And instruct the participant to read each word aloud as soon as it appears on the computer screen. Verify that the participant has read each word correctly during both reading tasks by looking at the screen as words are being read aloud.

TDCS is considered safe to use in humans, however, it is advisable that a first aid is at hand when performing TDCS to ensure that the participant's safety is not compromised, especially if they feel unwell or faint during the procedure. Never leave a participant unattended when administering TDCS Presoak two sponge electrodes with a surface area of 25 centimeter square in a standard 0.9%sodium chloride solution until they are saturated to administer inhibitory cathode or stimulation over the right cerebellar cortex. Place the blue electrode, one centimeter under and four centimeters to the right of the most prominent projection of the occipital bone, approximately the location of cerebellar lole seven.

To complete the electrode montage, place the red reference or anodal electrode on the right shoulder over the deltoid muscle. Secure the wet electrodes firmly to the head and upper arm with rubber straps or sulfur Durant wrap to ensure an optimal electrode skin interface. Make sure the electrodes are placed flat on the scalp and not over the hair.

Check that the intended position of the electrodes has not moved after they have been secured. Place a paper towel around the back of the participant's neck to mop up dripping saline solution. Set the intensity of stimulation at two milliamps and deliver for 20 minutes using a reliable current regulated DC stimulator to onset and offset each stimulation intervention increase and decrease respectively.

The DC current in a ramp like manner over 10 seconds to administer sham TDCS set the parameters to deliver sham stimulation for 20 minutes. Instead of the stimulation current, Apply odor cathode or sham stimulation to three separate groups of participants in pseudo random order. Ensure that the overall number, gender and average age of participants is comparable between groups Following brain stimulation.

Repeat the P-A-S-A-T and P-A-S-S-T as before in counterbalanced order. Then repeat the noun and verb reading tasks and the verb generation task in this order. Perform calculation, task experiments, and language task experiments in pseudorandom order.

This image shows accuracy scores before and after cerebellar TDCS. The numbers of correct responses selectively improved in the subtraction task compared to the addition task after cathode or stimulation in each of the following images. Asterisk show significant differences with the P value of less than 0.05 as revealed with corrected paired comparisons.

This figure shows mean total learning between repeated blocks, mean responses between blocks one to five were faster after TDCS during the verb generation task than during the noun reading and verb reading tasks. Finally, this image shows total learning variability between repeated blocks. The variability of responses between blocks one to five were more consistent after TDCS during the verb generation task than during the noun reading or verb reading tasks.

So once mastered the administration of TDCS, including the application of electrodes, can be done in about 30 to 40 minutes and about one and a half hours for the whole study if it is performed properly. While attempting this procedure, it's important to remember to position the electrodes correctly and to use the correct montage for the different groups and ensure proper training is given to ensure success.