84, p = 0.0003; GM concentration, patients < controls: t(13) = 4.68, p = 0.0004; WM concentration, patients > controls: t(13) = 4.97, p = 0.0003). In a masked analysis restricted to voxels within auditory-sensory regions, including auditory cortex, MGN, and IC, no significant differences were found between tinnitus patients and controls (p > 0.01). In a masked VBM analysis restricted to NAc voxels that demonstrated a significant functional difference between participant groups, there was no significant corresponding anatomical difference (p > 0.01). Similarly, in a masked fMRI analysis restricted to vmPFC voxels that demonstrated significant anatomical

between-group differences, we saw no significant functional difference Selleckchem LY294002 between tinnitus patients and controls (p > 0.01). So, no Selleckchem Dolutegravir single brain region exhibited both structural and functional differences. There was, however, a correlation between NAc fMRI signal and vmPFC VBM values in tinnitus patients (r = 0.73, t(8) = 2.99, p = 0.02; outlier removed; see Experimental Procedures), such that patients with the highest degree of NAc hyperactivity also had correspondingly greater anatomical differences (i.e.,

decreases in GM concentration and amount, with increased WM amount compared to controls; Figure 4A). This relationship was not present in control participants (r = −0.03, t(9) = −0.10, p = 0.919). Moreover, there was moderate correspondence between limbic abnormalities and primary auditory cortex hyperactivity in tinnitus patients (NAc x mHG: r = 0.51, t(8) = 1.67, p = 0.13, Figure 4B; vmPFC x mHG: r = 0.61, t(8) = 2.17, p = 0.06, Figure 4C). Correlations between limbic and posterior auditory areas were first not significant (NAc x pSTC; r = 0.17, t(8) = 0.49, p = 0.64, Figure 4D; vmPFC × pSTC: r = 0.42, t(8) = 1.30, p = 0.23, Figure 4E), nor was activity in primary and posterior auditory cortex related (mHG × pSTC: r = −0.13, t(8) = 0.38, p = 0.72, Figure 4F). This suggests that the degree of functional and structural differences in the limbic system (i.e., NAc and vmPFC, respectively) and primary auditory cortex may be directly related

in tinnitus patients. In this paper, we report both functional and structural markers of chronic tinnitus in limbic and auditory regions of the human brain. The most robust of these tinnitus-related differences were located in limbic areas previously shown to evaluate the significance of stimuli (Kable and Glimcher, 2009), including the nucleus accumbens (NAc; part of the ventral striatum) as well as the ventromedial prefrontal cortex (vmPFC). In tinnitus patients, the NAc exhibited hyperactivity specifically for stimuli matched to each patient’s tinnitus frequency (i.e., TF-matched). Corresponding anatomical differences were identified in the vmPFC, which is strongly connected to the ventral striatum (Di Martino et al., 2008 and Ferry et al., 2000).