Associative Behavioral Modification in Hermissenda : Cellular Correlates

Abstract

Three days of training consisting of trials of light paired with rotation produces a long-term modification of photopositive behavior in Hermissenda crassicornis. The behavioral modification depends on the temporal association of light and rotation. For animals that received light paired with rotation, significant increases in the spontaneous activity of type B photoreceptors were correlated with changes in photopositive behavior after training. A persistent tonic depolarization of type B photoreceptors can explain the cellular changes correlated with the long-term behavioral modification produced by the temporal association of light and rotation.

Higher-order associative processing in Hermissenda suggests multiple sites of neuronal modulation.

“…Specifically, chemosensory pathways are known to interact synaptically with and inhibit type B photoreceptors of the eye (Alkon et al 1978). This class of photoreceptor is known to exhibit an increase in excitability following paired conditioning that is strongly correlated with the magnitude of the conditioned response elicited by the light CS (Crow and Alkon 1980;Farley et al 1983;Matzel et al 1992). Briefly, the output of B photoreceptors is enhanced following conditioning and is thought to attenuate positive phototaxis through an inhibition of neighboring type A photoreceptors that mediate positive phototactic behavior (for review, see Alkon 1983;Goh and Alkon 1984).…”

Memory-Like Alterations inAplysiaAxons after Nerve Injury or Localized Depolarization

“…Neuronal LTH was one of the first correlates of learning reported in invertebrates and vertebrates (Woollacott and Hoyle, 1977;Brons and Woody, 1980;Crow and Alkon, 1980;Disterhoft et al, 1986;Scholz and Byrne, 1987;Walters, 1987). Dendritic and somatic hyperexcitability have recently been correlated with behaviorally expressed learning or long-term potentiation (LTP) in numerous preparations (for review, see Daoudal and Debanne, 2003;Zhang and Linden, 2003).…”

Inhibition of Conditioned Stimulus Pathway Phosphoprotein 24 Expression Blocks the Reduction in A-Type Transient K+Current Produced by One-TrialIn VitroConditioning ofHermissenda

“…Previous studies of associative learning in Hermissenda have shown that pavlovian conditioning results in long-term intrinsic enhanced excitability of neurons in the CS pathway (Crow and Alkon, 1980;Farley and Alkon, 1982;West et al, 1982;Crow, 1985;. Voltage-clamp studies identified a reduction in several K ϩ currents, I A and I K,Ca , as contributors to conditioning-dependent enhanced excitability (Alkon et al, Ϫ1 , where V 1/2 is the half-activation voltage, and k m is the maximum slope.…”

“…In Hermissenda, one site of intrinsic excitability changes produced by pavlovian conditioning is neurons in the conditioned stimulus (CS) pathway (Crow and Alkon, 1980;Farley and Alkon, 1982;Alkon et al, 1985;Crow, 1985Crow, , 1988Goh et al, 1985;Matzel et al, 1990;Frysztak and Crow, 1993, 1997Gandhi and Matzel, 2000;. In animals that exhibit intrinsic enhanced excitability, a cytoskeletal-related protein, the phosphorylation of which is regulated by conditioning, has been identified in components of the CS pathway Xue-Bian, 2000, 2002).…”