Methods for modifying electrical currents in neuronal circuits

1. A method for modifying neuronal activity within a brain of a mammal, the steps comprising:

a) using a magnetic resonance imaging (MRI) system to identify a location in the brain that is to receive pulses of focused ultrasound, the identified location including a live neuronal circuit in the brain of the mammal;

b) using an ultrasound system to apply pulses of focused ultrasound to the identified location to release naturally occurring hormones and modulating a level of the naturally occurring hormones, each pulse of focused ultrasound having (i) a prescribed tone burst duration (TBD) in a range of 2-100 milliseconds (ms) and the pulses being applied during a continuous sonication period having a prescribed total sonication duration (TSD) between 0.1 and 2 seconds in order to increase neuronal activity of the neuronal circuit and increase a BOLD response of the neuronal circuit that is measurable using the MRI, or (ii) a TBD less than 2 ms and the pulses being applied during a sonication period having a TSD between 2 and 9 seconds in order to decrease neuronal activity of the neuronal circuit and inhibit the measurable BOLD response.

2. The method as recited in claim 1 in which the pulses of focused ultrasound are applied in step b) in a sequence according to a selected pulse repetition frequency (PRF) in the range of 100-1000 hertz (Hz) in order to further decrease neuronal activity, or at a selected PRF below 100 Hz in order to further increase neuronal activity.

3. The method as recited in claim 2 in which applying the pulses of focused ultrasound at a selected PRF in the range of 100-1000 Hz when the TSD has a duration between 2 and 9 seconds induces a decrease in neuronal activity.

4. The method as recited in claim 1 in which the pulses of focused ultrasound are applied in step b) with an acoustic intensity in the range of 10-350 watts per centimeter squared (W/cm 2 ).

5. The method as recited in claim 1 in which step a) includes:

a) i) acquiring image data from the brain;

a) ii) reconstructing an image of the brain from the acquired image data; and

a) iii) identifying the location in the brain using the reconstructed image.

6. The method as recited in claim 1 further comprising:

c) acquiring, with the MRI system, images of the brain while step b) is performed, the acquired images being indicative of the modified neuronal activity induced by the applied pulses of focused ultrasound;

d) administering a pharmaceutical medication to the brain; and

e) repeating steps b) and c) in order to acquire images indicative of neuronal activity that is induced by the applied pulses of focused ultrasound and altered in response to the administered pharmaceutical medication.

7. The method as recited in claim 6 further comprising comparing the images acquired in step e) with the images acquired in step c) in order to assess an efficacy of the pharmaceutical medication.

8. The method as recited in claim 1 in which the identified location in the brain is selected to include at least one of gray matter and white matter.

9. The method as recited in claim 1 further comprising:

c) acquiring, with the MRI system, images of the brain while step b) is performed, the acquired images being indicative of the modified neuronal activity induced by the applied pulses of focused ultrasound;

d) adjusting a parameter of the applied pulses of focused ultrasound using the acquired images of the brain; and

e) repeating step b) using the adjusted parameter of the applied pulses of focused ultrasound.

10. The method as recited in claim 9 in which the adjusted parameter of the pulses of focused ultrasound includes at least one of the TBD, the duration of the sonication period, a pulse repetition frequency at which the pulses of focused ultrasound are applied, an acoustic intensity, an ultrasound frequency, a focal depth and a focal diameter.

11. The method as recited in claim 1 further comprising:

c) acquiring, with the MRI system, images of the brain while step b) is performed, the acquired images being indicative of the modified neuronal activity induced by the applied pulses of focused ultrasound;

d) repeatedly performing steps a)-c) over a period of time of sufficient length so that neuronal circuits are significantly modified by the repeated application of pulses of focused ultrasound; and

wherein the neuronal circuits are modified such that at least one of a psychiatric, neurological, and neuroendocrine disorder is treated, and the modified neuronal circuits are assessed using the images acquired in step c).

12. A method for modifying neuronal activity within a brain of a mammal, the steps comprising:

a) using a magnetic resonance imaging (MRI) system to identify a location in the brain that is to receive pulses of focused ultrasound, the identified location including a live neuronal circuit;

b) using an ultrasound system to apply pulses of focused ultrasound to the identified location to release naturally occurring hormones and modulating a level of the naturally occurring hormones, wherein the pulses of focused ultrasound are applied at a selected pulse repetition frequency (PRF) in the range of 100-1000 hertz (Hz) during a continuous sonication period having a prescribed total sonication duration (TSD) between 2 and 9 seconds in order to decrease neuronal activity of the neuronal circuit, or at a selected PRF below 100 Hz during a sonication period having a TSD between 0.1 and 2 seconds in order to increase neuronal activity of the neuronal circuit, wherein the neuronal activity that is increased or decreased is a BOLD response that is measurable using the MRI.

13. The method as recited in claim 12 in which the duration of each pulse of focused ultrasound applied in step b) has a selected tone burst duration (TBD) in the range of 2-100 milliseconds (ms) in order to further increase neuronal activity, or a selected TBD below 2 ms in order to further decrease neuronal activity.

14. The method as recited in claim 12 in which the pulses of focused ultrasound are applied in step b) with an acoustic intensity in the range of 10-350 watts per centimeter squared (W/cm 2 ).