Functional Recovery After Hemilabyrinthectomy in Goldfish

Grant Winners

  • Richard Spieler, Ph.D. – Oceanographic Center
  • Jaime Tartar, Ph.D. – Farquhar College of Arts and Sciences
  • Brian Moe, B.S. – Oceanographic Center
  • Hunter Noren, B.S. – Oceanographic Center


  • Richard E Dodge, PhD. – Oceanographic Center
  • Don Rosenblum, Ph.D. – Farquhar College of Arts and Sciences


Award Winners

We propose to evaluate the potential of memory-enhancing drugs (nootropics) to promote recovery in the goldfish model of hemilabyrinthectomy. In this lesion model, unilateral removal of the labyrinth induces a postural imbalance in response to light (Dorsal Light Reflex, DRL), from which the animals recover over time, This recovery, once thought to be simply anatomical reorganization, is now understood to be a complex process involving neuroprotection, neuroplasticity, neurogenesis and a host of neurotransmitter processes. The hemilabyrinthectomy model has been used, with multiple vertebrates, to study the vestibular system with an eye to understanding pathological conditions as well as functional recovery of the central nervous system (CNS). There have been studies, with mixed results, examining nootropics on functional recovery after damage to the CNS, predominately damage caused by stroke. Interpretation of the results of these studies has been confounded by sample size and variable damage. However, apparently no studies using nootropics have been done with any hemilabyrinthectomy model. We will examine the effect of Modafinil, Piracetam, Adderall, and Senktide on the DRL of goldfish. All these compounds have been demonstrated to enhance memory and learning in vertebrates. The experimental methodology consists of removing the right labyrinth organ of anesthetized goldfish and testing them daily in a darkened aquarium with a single light at a 900 angle to the aquarium. Post-surgery, the animal will initially lie sideways with its dorsum oriented to the light rather than in its normal vertical position. Through time the animal recovers its normal pre-operation orientation. The angle of orientation, from 0 to 900, is measured daily and indicates the rate of recovery. A sample size of 15 fish for each drug and two control (sham-operated and intact) groups will be tested and the resulting data analyzed statistically in order to determine the effect of each drug.