This study analyzes the anatomical differences in white matter and frontothalamic projections, as well as variations in brain activation at rest and in response to moral dilemmas, among control individuals, individuals with depression without suicidal ideation, and individuals with depression and suicidal ideation using functional magnetic resonance imaging (fMRI), thus addressing the interaction between neuroanatomy, emotions, and decision-making. The sample consisted of 56 people aged between 19 and 55 years. The participants were divided into three groups: control (n=17), depression without suicidal ideation (n=19), and depression with suicidal ideation (n=20). The classification was based on participants’ diagnoses. A total of 25 men and 31 women were selected, with an average age of 30.6 years (SD=2.34). The study found significant correlations, using Spearman’s correlation coefficient, between amygdala hypoactivity and suicidal ideation at rest (=−.038; p<0.001), while in situations involving moral dilemmas, the anterior cingulate gyrus and insula showed greater activity in patients with suicidal ideation, reflecting an intensification of negative emotions. The results suggest that patients with suicidal ideation have difficulty activating self-preservation mechanisms, which may be due to dysfunction in the connectivity and functioning of the amygdala. Despite the limitations related to the study design or sample size, the findings offer valuable insights into the neurobiological basis of suicide.