Techniques for selecting signal delivery sites and other parameters for treating depression and other neurological disorders, and associated systems and methods

1. A method for treating a patient, comprising:

obtaining first imaging information corresponding to a first region of a patient's brain, the first imaging information being based at least in part on functional characteristics of the first region;

obtaining second imaging information corresponding to a second region of the patient's brain, the second region being a subset of the first region, the second imaging information being based at least in part on functional or structural characteristics of the second region;

selecting a target neural population based at least in part on the second imaging information; and

applying an electromagnetic signal to the target neural population to improve a patient function;

wherein obtaining first imaging information includes obtaining first imaging information of the patient's middle frontal gyrus.

2. The method of claim 1 wherein obtaining second imaging information includes obtaining second imaging information having a higher resolution than the first imaging information.

3. The method of claim 1 wherein obtaining second imaging information includes obtaining at least one of fractional anisotropy information and diffusion tensor imaging information.

4. The method of claim 1 wherein obtaining first imaging information includes obtaining first imaging information using fMRI techniques.

5. The method of claim 4 wherein obtaining first imaging information includes obtaining first information on a real-time or approximately real-time basis, and wherein obtaining the second information includes using spectroscopy techniques while the patient is present.

6. The method of claim 1 wherein obtaining second imaging information includes obtaining information including a thickness value of gray matter in the second region.

7. The method of claim 1 , further comprising identifying the patient as having depression, and wherein:

obtaining first imaging information includes obtaining functional magnetic resonance imaging information while engaging the patient in a task selected to trigger an emotional response in the patient, the first imaging information having a first resolution; and wherein

obtaining second imaging information includes obtaining diffusion tensor imaging information having a second resolution greater than the first resolution, and wherein the method further comprises obtaining a fractional anisotropy level for the patient, and, based at least in part on the fractional anisotropy level, determining whether the patient is a suitable candidate for receiving an electromagnetic signal; and wherein

applying an electromagnetic signal includes applying an electrical signal from an electrode positioned within the patient's skull cavity and outside a cortical surface of the patient's brain.

8. A method for treating a patient, comprising:

identifying a patient as having depression;

obtaining first imaging information corresponding to a first region of a patient's brain, the first imaging information being obtained by functional magnetic resonance imaging techniques, the first region including the patient's DLPFC;

obtaining second imaging information corresponding to a second region of the patient's brain, the second region being a subset of the first region, the second imaging information being based at least in part on identifying neuronal fibers using diffusion tractography techniques;

selecting a signal delivery site based at least in part on the second imaging information;

implanting at least one electrode proximate to the signal delivery site, within the patient's skull and outside a cortical surface of the patient's brain; and

reducing or eliminating patient depression by preferentially directing electrical signals from the at least one electrode to the signal delivery site;

wherein selecting a signal delivery site includes selecting a signal delivery site based at least in part on a characteristic of neuronal fibers projecting from the signal delivery site to Brodmann area 25.

9. The method of claim 8 wherein obtaining second imaging information includes obtaining a number of neuronal tracts.

10. The method of claim 8 wherein obtaining second imaging information includes obtaining a density of neuronal tracts.

11. The method of claim 8 wherein obtaining first imaging information includes obtaining first imaging information while the patient performs a working memory task.

12. The method of claim 8 wherein obtaining first imaging information includes obtaining first imaging information while the patient is exposed to an emotional trigger stimulus.

13. The method of claim 8 , further comprising obtaining a fractional anisotropy level for the patient, and, based at least in part on the fractional anisotropy level, determining whether the patient is a suitable candidate for receiving an electromagnetic signal.

14. The method of claim 13 wherein determining includes determining that the fractional anisotropy level is below an average value for a generalized patient population, and above a threshold value.