Alternatively, it is also possible to interpret that the globus pallidus
is mediating attentional control rather than voice-specific
processing. The basal ganglia have been implicated in treatment
intervention of schizophrenia [19], as well as its dopaminergic
relation to the schizophrenia pathology [20]. Specifically, disrupted
attention has been proposed to be involved in hallucinations
[21,22] and attention has been shown to modulate auditory hallucination
in non-clinical individuals with auditory hallucination
[23,24]. While the effectiveness of atypical antipsychotics to hallucinations
are well known [25], atypical antipsychotics were shown to reduce the globus pallidus activation during an attentional
control task resulting in improved attentional control [26].
Thus, the current finding, where the globus pallidus activation
correlated with hallucination severity, could be interpreted as a
sign of disrupted attention in individuals with greater hallucination
severity, specifically to the external auditory human voice,
which usually is a form of actual auditory hallucinations. We
would argue, however, that the current results favor the subvocal
interpretation rather than the attentional interpretation, because
non-hallucinatory BPRS, including thought disturbances, did not
show a significant correlation with the globus pallidus activation. In
addition, the 1-back performance, which would reflect their attention,
did not show association with pallidal activations.