Copy number variants (CNVs) are strongly linked to psychiatric disorders and brain structural changes. This study investigated the contribution of *Tbx1*, a gene within the 22q11.2 CNV region, to these alterations using *Tbx1* heterozygous mice. Volumetric MRI revealed reduced amygdala volumes (anterior and posterior) and increased auditory cortex volumes. Behaviorally, these mice showed impaired social incentive learning and acoustic sensorimotor gating, but not non-acoustic gating. These findings highlight *Tbx1*'s role in brain structure and specific behavioral dimensions.
