Electrical microglial cell activation

1. A method comprising:

positioning electrodes in or in contact with a head of a subject identified as in need of enhanced microglial cell activation; and

activating control circuitry to drive the electrodes to apply an electrical current to a brain of the subject in pulses having an average pulse duration of between 0.1 ms and 10 ms, and to configure the electrical current to:

enhance microglial cell activation for taking up a substance from brain parenchyma with a first duty cycle during a treatment period having a duration of at least one hour, and

enhance clearance of the substance from brain parenchyma to outside the brain parenchyma with a second duty cycle during the treatment period, wherein the second duty cycle is greater than the first duty cycle,

wherein the substance is selected from a group consisting of: amyloid beta and tau protein, and

wherein activating the control circuitry comprises activating the control circuitry to apply the electrical current with an average amplitude of between 0.1 and 5 mA, or with an average voltage that results in between 0.1 and 5 mA current.

2. The method according to claim 1 , wherein the substance is amyloid beta, and wherein activating the control circuitry comprises activating the control circuitry to configure the electrical current to enhance the microglial cell activation for taking up the amyloid beta from the brain parenchyma and to enhance the clearance of the beta amyloid from brain parenchyma to outside the brain parenchyma.

3. The method according to claim 1 , wherein positioning the electrodes comprises positioning the electrodes in or in contact with the head of a subject identified as at risk of or suffering from Alzheimer's disease.

4. The method according to claim 1 , wherein positioning the electrodes comprises positioning the electrodes in or in contact with the head of a subject identified as at risk of or suffering from cerebral amyloid angiopathy (CAA).

5. The method according to claim 1 , wherein positioning the electrodes comprises implanting at least one of the electrodes intracranially.

6. The method according to claim 5 , wherein implanting the at least one of the electrodes intracranially comprises implanting the at least one of the electrodes in brain parenchyma.

7. The method according to claim 6 ,

wherein the at least one of the electrodes is a parenchymal electrode, and

wherein positioning the electrodes further comprises implanting at least one cerebrospinal fluid (CSF) electrode of the electrodes in a CSF-filled space of the brain, the CSF-filled space selected from a group consisting of: a ventricular system and a subarachnoid space, and

wherein activating the control circuitry comprises activating control circuitry to drive the parenchymal and the CSF electrodes to apply the electrical current to enhance the microglial cell activation for taking up the substance from the brain parenchyma.

8. The method according to claim 5 , wherein implanting the at least one of the electrodes comprises implanting the at least one of the electrodes in electrical contact with brain parenchyma.

9. The method according to claim 8 ,

wherein the at least one of the electrodes is a parenchymal electrode, and

wherein positioning the electrodes further comprises implanting at least one cerebrospinal fluid (CSF) electrode of the electrodes in a CSF-filled space of the brain, the CSF-filled space selected from a group consisting of: a ventricular system and a subarachnoid space, and

wherein activating the control circuitry comprises activating control circuitry to drive the parenchymal and the CSF electrodes to apply the electrical current to enhance the microglial cell activation for taking up the substance from the brain parenchyma.

10. The method according to claim 5 , wherein implanting at least one of the electrodes intracranially comprises implanting the at least one of the electrodes in a CSF-filled space of the brain, the CSF-filled space selected from a group consisting of: a ventricular system and a subarachnoid space.

11. The method according to claim 1 , wherein positioning the electrodes comprises positioning at least one of the electrodes outside and in electrical contact with a skull of the head.

12. The method according to claim 1 , wherein positioning the electrodes comprises positioning at least one of the electrodes on an external surface of skin of the head.

13. The method according to claim 1 , wherein activating the control circuitry comprises activating the control circuitry to configure the electrical current to have a frequency of between 10 and 90 Hz.

14. The method according to claim 1 , wherein activating the control circuitry to configure the electrical current to enhance the clearance of the substance from the brain parenchyma to outside the brain parenchyma comprises activating the control circuitry to configure the electrical current to clear the substance from the brain parenchyma to a CSF-filled space of the brain selected from a group consisting of: a ventricular system and a subarachnoid space.

15. A method comprising:

positioning electrodes in or in contact with a head of a subject identified as in need of enhanced microglial cell activation; and

activating control circuitry to drive the electrodes to apply an electrical current to a brain of the subject in pulses having an average pulse duration of between 0.1 ms and 10 ms, and to configure the electrical current to:

enhance microglial cell activation for taking up a substance from brain parenchyma, and

enhance clearance of the substance from brain parenchyma to outside the brain parenchyma,

wherein the substance is selected from a group consisting of: amyloid beta and tau protein,

wherein activating the control circuitry comprises activating the control circuitry to apply the electrical current with an average amplitude of between 0.1 and 5 mA, or with an average voltage that results in between 0.1 and 5 mA current,

wherein activating the control circuitry to configure the electrical current to enhance the microglial cell activation for taking up the substance from the brain parenchyma comprises activating the control circuitry to configure the electrical current as alternating current, and

wherein activating the control circuitry to configure the electrical current to enhance the clearance of the substance from the brain parenchyma to outside the brain parenchyma comprises activating the control circuitry to configure the electrical current as direct current.

16. The method according to claim 15 , wherein activating the control circuitry comprises activating the control circuitry to apply the electrical current in pulses with a duty cycle of between 1% and 50%.

17. The method according to claim 15 , wherein the substance is amyloid beta, and wherein activating the control circuitry comprises activating the control circuitry to configure the electrical current to enhance the microglial cell activation for taking up the amyloid beta from the brain parenchyma and to enhance the clearance of the beta amyloid from brain parenchyma to outside the brain parenchyma.

18. The method according to claim 15 , wherein positioning the electrodes comprises positioning the electrodes in or in contact with the head of a subject identified as at risk of or suffering from Alzheimer's disease.

19. The method according to claim 15 , wherein positioning the electrodes comprises implanting at least one of the electrodes intracranially.

20. The method according to claim 15 , wherein positioning the electrodes comprises positioning at least one of the electrodes outside and in electrical contact with a skull of the head.

21. The method according to claim 15 , wherein positioning the electrodes comprises positioning at least one of the electrodes on an external surface of skin of the head.

22. The method according to claim 15 , wherein activating the control circuitry comprises activating the control circuitry to configure the electrical current to have a frequency of between 10 and 90 Hz.

23. The method according to claim 15 , wherein activating the control circuitry to configure the electrical current to enhance the clearance of the substance from the brain parenchyma to outside the brain parenchyma comprises activating the control circuitry to configure the electrical current to clear the substance from the brain parenchyma to a CSF-filled space of the brain selected from a group consisting of: a ventricular system and a subarachnoid space.

24. A method comprising:

positioning electrodes in or in contact with a head of a subject identified as in need of enhanced microglial cell activation; and

activating control circuitry to drive the electrodes to apply an electrical current to a brain of the subject in pulses having an average pulse duration of between 0.1 ms and 10 ms, and to configure the electrical current to:

enhance microglial cell activation for taking up a substance from brain parenchyma, and

enhance clearance of the substance from brain parenchyma to outside the brain parenchyma,

wherein the substance is selected from a group consisting of: amyloid beta and tau protein,

wherein activating the control circuitry comprises activating the control circuitry to apply the electrical current with an average amplitude of between 0.1 and 5 mA, or with an average voltage that results in between 0.1 and 5 mA current,

wherein activating the control circuitry to configure the electrical current to enhance the microglial cell activation for taking up the substance from the brain parenchyma comprises activating the control circuitry to configure the electrical current as direct current, and

wherein activating the control circuitry to configure the electrical current to enhance the clearance of the substance from the brain parenchyma to outside the brain parenchyma comprises activating the control circuitry to configure the electrical current as direct current.

25. The method according to claim 24 , wherein the substance is amyloid beta, and wherein activating the control circuitry comprises activating the control circuitry to configure the electrical current to enhance the microglial cell activation for taking up the amyloid beta from the brain parenchyma and to enhance the clearance of the beta amyloid from brain parenchyma to outside the brain parenchyma.

26. The method according to claim 24 , wherein positioning the electrodes comprises positioning the electrodes in or in contact with the head of a subject identified as at risk of or suffering from Alzheimer's disease.

27. The method according to claim 24 , wherein positioning the electrodes comprises implanting at least one of the electrodes intracranially.

28. The method according to claim 24 , wherein positioning the electrodes comprises positioning at least one of the electrodes outside and in electrical contact with a skull of the head.

29. The method according to claim 24 , wherein positioning the electrodes comprises positioning at least one of the electrodes on an external surface of skin of the head.

30. The method according to claim 24 , wherein activating the control circuitry comprises activating the control circuitry to configure the electrical current to have a frequency of between 10 and 90 Hz.

31. The method according to claim 24 , wherein activating the control circuitry to configure the electrical current to enhance the clearance of the substance from the brain parenchyma to outside the brain parenchyma comprises activating the control circuitry to configure the electrical current to clear the substance from the brain parenchyma to a CSF-filled space of the brain selected from a group consisting of: a ventricular system and a subarachnoid space.