Direct Electrical Stimulation in the Human Brain Disrupts Melody Processing

Abstract

Summary Prior research using functional magnetic resonance imaging (fMRI) [1–4] and behavioral studies of patients with acquired or congenital amusia [5–8] suggest that the right posterior superior temporal gyrus (STG) in the human brain is specialized for aspects of music processing (for review see 9–12). Intracranial electrical brain stimulation in awake neurosurgery patients is a powerful means to determine the computations supported by specific brain regions and networks [13–21], because it provides reversible causal evidence with high spatial resolution (for review, see [22, 23]). Prior intracranial stimulation or cortical cooling studies have investigated musical abilities related to reading music scores [13, 14] and singing familiar songs [24, 25]. However, individuals with amusia (congenitally, or from a brain injury) have difficulty humming melodies but can be spared for singing familiar songs with familiar lyrics [26]. Here we report a detailed study of a musician with a low-grade tumor in the right temporal lobe. Functional MRI was used pre-operatively to localize music processing to the right STG, and the patient subsequently underwent awake intraoperative mapping using direct electrical stimulation during a melody repetition task. Stimulation of the right STG induced ‘music arrest’ and errors in pitch, but did not affect language processing. These findings provide causal evidence for the functional segregation of music and language processing in the human brain, and confirm a specific role of the right STG in melody processing.

Domain-Specific Diaschisis: Lesions to Parietal Action Areas Modulate Neural Responses to Tools in the Ventral Stream

“…We studied a series of consecutively recruited patients in the pre-operative phase of their neurosurgical care (n = 35). Each patient completed the same functional MRI experiment prior to neurosurgery in which they viewed or named gray-scale pictures of tools, animals, famous faces and famous places (for precedent, see Garcea et al 2017). No patients had lesions extending into the left fusiform gyrus; lesions were distributed throughout anterior (medial and lateral) temporal regions, and parietal and frontal regions (see Supplementary Fig.…”

“…All neurosurgery and healthy adult volunteers participated in the study in exchange for payment, and gave written informed consent in accordance with the University of Rochester Research Subjects Review Board. The results obtained from the neurosurgery patients were used in each case to assist surgical planning to preserve eloquent cortex (e.g., see Garcea et al 2017;Chernoff et al under review).…”

“…Within each run, 8 miniblocks of intact images and 4 miniblocks of phase-shifted versions of the stimuli were presented with the constraint that a category of objects did not repeat during two successive miniblock presentations. Participants who saw 6-s miniblocks took part in 8 runs (91 volumes per run) while participants who saw 12-s miniblocks completed 4 runs (152 volumes per run; for precedent in using this task with neurosurgery patients, see Garcea et al 2017).…”

A common neural signature of brain injury in concussion and subconcussion

“…Participants were tested on a Siemens 3T Tim Trio scanner using a 32-channel head coil located at the Rochester Center for Brain Imaging (since renamed to "Center for Advanced Brain Imaging and Neurophysiology"). High-resolution structural T1 contrast images were acquired using a magnetization-prepared rapid gradient echo (MP-RAGE) pulse sequence at the start of each participant's first scanning session [repetition time (TR) = 2530, echo time (TE) = 3.44 ms, flip angle = 7°, field of view (FOV) = 256 mm, matrix = 256 × 256, 1 mm × 1 mm × 1 mm sagittal left-to-right slices] (25). DTI was acquired using a single-shot spin-echo echoplanar imaging (SE-EPI) (60 diffusion directions with b = 1200 s/mm 2 , 10 images with b = 0 s/mm 2 , TR = 8900 ms, TE = 86 ms, FOV = 256 × 256 mm 2 , matrix = 128 × 128, voxel size = 2 mm 3 by 2 mm 3 by 2 mm 3 , 70 axial slices) (25).…”

Altered functional connectivity during speech perception in congenital amusia

“…Using a data-driven approach, we identified four regions in left and right inferior frontal cortex for which the amusic group exhibited decreased functional connectivity with several other sites in frontal, temporal and occipital cortex. The most prominent of these results was decreased connectivity between left frontal regions classically implicated in language processing (left IFG and DLPFC) and right hemisphere regions -in the superior temporal gyrus and sulcus, Heschl's gyrus, and anterior insula-that have been implicated in pitch processing (Lee et al, 2011;Garcea et al, 2017;Warren et al, 2003). We suggest that this decreased connectivity between right hemisphere pitch and left hemisphere frontal cortices may relate to the unreliability of the amusics' perception of and memory for pitch.…”