Glycoprotein Synthesis Is Necessary for Memory of Sickness-Induced Learning in Chicks

Can current biochemical models of memory account for sickness-induced learning? We show that chicks can form an association between pecking a coloured but tasteless lure and becoming ill (LiCl, i.p.) 30 min later. We go on to demonstrate amnesia for this association, induced by intracranial administration of 2-deoxygalactose (10 micromole per hemisphere, in a 10 microl vol), an inhibitor of the synthesis of glycoproteins of the synaptic membrane, 10 min before pecking. Further, we show that this 2-deoxygalactose-induced amnesia is not state dependent. Thus the brain representation of the lure must be held, and require macromolecular syntheses, similar to those found in other forms of learning, for a considerable time before it can be associated with new significant experience. This is incompatible with contiguous synaptic firing views of memory.