Open AccessAging in Sensory and Motor Neurons Results in Learning Failure in Aplysia californica
Author(s) -
Andrew T. Kempsell,
Lynne A. Fieber
Publication year - 2015
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0127056
Subject(s) - aplysia , neuroscience , facilitation , biology , sensitization , stimulus (psychology) , sensory system , nervous system , neural facilitation , reflex , long term potentiation , withdrawal reflex , neuroplasticity , bursting , psychology , excitatory postsynaptic potential , inhibitory postsynaptic potential , cognitive psychology , biochemistry , receptor
The physiological and molecular mechanisms of age-related memory loss are complicated by the complexity of vertebrate nervous systems. This study takes advantage of a simple neural model to investigate nervous system aging, focusing on changes in learning and memory in the form of behavioral sensitization in vivo and synaptic facilitation in vitro. The effect of aging on the tail withdrawal reflex (TWR) was studied in Aplysia californica at maturity and late in the annual lifecycle. We found that short-term sensitization in TWR was absent in aged Aplysia . This implied that the neuronal machinery governing nonassociative learning was compromised during aging. Synaptic plasticity in the form of short-term facilitation between tail sensory and motor neurons decreased during aging whether the sensitizing stimulus was tail shock or the heterosynaptic modulator serotonin (5-HT). Together, these results suggest that the cellular mechanisms governing behavioral sensitization are compromised during aging, thereby nearly eliminating sensitization in aged Aplysia .