Burst-Induced Anti-Hebbian Depression Acts through Short-Term Synaptic Dynamics to Cancel Redundant Sensory Signals

• DOI: 10.1523/jneurosci.0303-10.2010
• Publication Date: 2010-04-28T16:53:04Z
• Authors: Erik Harvey-Girard; John Lewis; Leonard Maler
• Keywords: Parallel fiber; Post-tetanic potentiation; Tetanic stimulation; Electric fish

Weakly electric fish can enhance the detection and localization of important signals such as those prey in part by cancellation redundant spatially diffuse due to, e.g., their tail bending. The mechanism is based on descending input, conveyed parallel fibers emanating from cerebellar granule cells, that produces a negative image global low-frequency pyramidal cells within first-order electrosensory region, lateral line lobe (ELL). Here we demonstrate fiber synaptic input to ELL cell undergoes long-term depression (LTD) whenever both afferents target are stimulated produce paired burst discharges. Paired large bursts (4-4) induce robust LTD over pre-post delays up +/-50 ms, whereas smaller (2-2) weaker LTD. Single spikes (either presynaptic or postsynaptic) with did not Tetanic stimulation was also ineffective inducing Thus, have demonstrated form anti-Hebbian depends temporal correlation discharge. We then burst-induced postsynaptic requires NR2B subunit NMDA receptor, elevation Ca(2+), activation CaMKIIbeta. A model incorporating local inhibitory circuitry previously identified short-term potentiation synapses further suggests combination LTD, potentiation, inhibition may be sufficient explain generation sensory cells.