  In this paper we give a geometrical interpretation of an extension of mixed
Hodge structures (MHS) obtained from the canonical MHS on the group ring of the
fundamental group of a hyperelliptic curve modulo the fourth power of its
augmentation ideal. We show that the class of this extension coincides with the
regulator image of a canonical higher cycle in a hyperelliptic jacobian. This
higher cycle was introduced and studied by Collino.
