Postcommissural fibers

The postcommissural fibres of the fornix are fibres of the columns of the fornix that curve posterior to the anterior commissure. They are distinguished from the precommissural fibres, which pass anterior to the commissure.

These fibres arise predominantly from the subiculum and form the subiculothalamic pathway, an important component of limbic memory circuitry. They follow two principal routes: a direct pathway from the subiculum to the anterior thalamic nuclei, and an indirect pathway that first terminates in the mammillary bodies, which then project to the anterior thalamic nuclei. These connections form part of the circuit of Papez and contribute to memory-related processing.