Best Neuroscience and Psychoanalysis

Working out the biological basis of categorization in the real world is precisely one of the main goals of Edelman . Edelman’s ideas are of interest not only because of his focus on processes of self-organization which provide the organism with the required adaptive potential, but because he considers memory from an embodied perspective. The notion of “memory as recategorization” is based on processes of sensory–motor coordination which in a very direct sense anchor memory, or its manifestation in behavior, in the interaction of an individual with the environment.

We want to pick up two central ideas of Edelman here, sensory–motor coordination and value systems. The general framework proposed by Edelman suggests that the results of motor activity are an integral part of categorization. “While sensation and perhaps certain aspects of perception can proceed without a contribution of the motor apparatus, perceptual categorization depends upon the interplay between local cortical sensory maps and local motor maps. The strongest consequence of this assumption is that categorization cannot be a property of one small portion of the nervous system” . Thus, categorization involves not only the brain but also the sensory–motor apparatus, a key implication of the principles of sensory–motor coordination. The essential mechanism of categorization in Edelman’s framework is a parallel sampling of the environment by multiple sensory maps within the same modality and between different modalities. This sampling is a process of sensory–motor coordination in which various maps pick up different, but temporally correlated, signals from the environment. These correlations play a fundamental role in categorization . Edelman illustrates the principle of sensory–motor coordination as shown in Fig. 2.

Thelen and Smith point out that “this perfect temporal association of multimodal information is perhaps the only perceptual invariant that spans all ages, contexts and modalities. We believe, with Edelman, that this correlation is the primary link between the mind and the world.” This is a central point in embodied memory theory: sensory–motor coordination structures the high-dimensional sensory space by inducing regularities. The temporal correlation of signals in the neural maps related to the different sensory modalities, generated by the interaction with an object, is the most basic example of such regularities.Which of these patterns of correlations are chosen or selected in the process of categorization is modulated by a value system. Value systems are basic evolutionary adaptations that define broad behavioral goals of an organism. For example, if an organism succeeds in grasping an object or sticking it into its mouth, a value signal is generated that enables the association of the activation in the neural maps corresponding to the different sensory and proprioceptive modalities. In this way the organism is capable of generating categories on its own as it interacts with the environment. To take our example again: Peter learns to differentiate between apples and newspapers by picking up apples and newspapers and sticking them into his mouth. The two sequences of events lead to different activations in the different neural maps which are then, via the modulation of the value system, associated with each other. If a new situation affords this, a new category has to be developed. Because there is no limit to the patterns of sensory stimulation, new perceptual categories can be formed.