Abstract

Honeybees contradict the notion that insect behaviour tends to be relatively inflexible and stereotypical: they live in colonies and exhibit complex social, navigational and communication behaviours as well as a relatively rich cognitive repertoire. Because these relatively complex behaviours are controlled by a brain consisting of only 1 million or so neurons, honeybees offer an opportunity to study the relationship between behaviour and cognition in neural networks that are limited size and complexity. I shall report electro- and optophysiological studies aiming to characterize memory traces at the single neuron and network level. The key structure will be the mushroom body, a high order integration centre of the insect brain. At its input sites the memory trace appears to be coded in the combinatorics of multiple sensory inputs, and at its output sites in multiple processing categories that represent the acquired values. This framework offers a structure for experimental and modeling approaches and prevents us from believing that the properties of the memory trace can be captured by just assuming flexible and experience dependent sensory-interneuron-motor connections. Rather we have to search for the coding/recoding, evaluating and predicting processes involved in storing the contents of memory, the engram. I conclude that the memory engram will not be found in single of neurons. Rather it results from distributed network properties that add their respective contents when memory is formed, processed (consolidated), and retrieved.

Suggested reading: Menzel, R. 2012. The Honeybee as a model for understanding the basis of cognition. Nature Reviews Neuroscience 13, 758-768.