Characterization of transcranial ultrasonic passage in the Göttingen minipig

There is continuing interest in targeted transcranial stimulation of deep brain structures using techniques such as low intensity focused ultrasound (LIFU). Accurate transcranial targeting and dosage of acoustic energy onto target neural structure requires quantification of the acoustic effect the skull has on the ultrasound wave. The objective of this work is to assess the effect of transcranial passage, both in terms of attenuation and orientation of an incident acoustic wave, in the gyrencephalic Göttingen minipig. Precision measurements of the acoustic transit of the stereotactically addressed intact-skulls resulted in a consistently measured acoustic loss of about 8.5 dB from the skull transition, corresponding to an intensity transmission coefficient of 0.1298 ± 0.00990. Negligible spatial shift in the acoustic focus was observed. These results indicate that the Göttingen minipig may be suitable for studies of targeted transcranial neuromodulation due to the predictable acoustic transmission measured from the intact skull.