We propose a tripartite mechanism to describe the processing of cognitive information (cog-info), comprising the (1) neuron, (2) surrounding neural extracellular matrix (nECM), and (3) numerous "trace" metals distributed therein. The neuron is encased in a polyanionic nECM lattice doped with metals (>10), wherein it processes (computes) and stores cog-info. Each [nECM:metal] complex is the molecular correlate of a cognitive unit of information (cuinfo), similar to a computer "bit". These are induced/sensed by the neuron via surface iontophoretic and electroelastic (piezoelectric) sensors. The generic cuinfo are used by neurons to biochemically encode and store cog-info in a rapid, energy efficient, but computationally expansive manner. Here, we describe chemical reactions involved in various processes that underline the tripartite mechanism. In addition, we present novel iconographic representations of various types of cuinfo resulting from"tagging" and cross-linking reactions, essential for the indexing cuinfo for organized retrieval and storage of memory. KEYWORDS: Memory, tripartite model, cognitive unit of information (cuinfo), neuron, extracellular matrix, trace metal W hat is biologic memory? How can one describe the sensation of "memory" in molecular terms? What is the atomic correlate of memory? How is memory stored and lost? What formalism describes the encoding and storage of cognitive information (cog-info)?One would like to formulate a molecular mechanism that is physiologically credible and biochemically based. It must operate rapidly (faster than neural firing at <100 ms) with available biological materials in an aqueous environment at 37°C , using ∼400 cal/day, and offer huge computational capabilities. It should permit a chemical explanatory framework for describing "synaptic plasticity" and "long-term potentiation" (LTP) 1−6 or forgetting.In a previous article, we proposed a "tripartite" mechanism, wherein neurons, encased in a lattice of neural extracellular matrix (nECM), employ more than 10 trace metals (dopants) to encode, store, and decode cog-info. 7 The neurons employ the nECM as an "information lattice", comparable to the workings of a computer memory chip which encodes, stores, and retrieves binary "bits" (0/1) in an inorganic matrix. Neurons also release vesicles containing neurometals (Cu 2+ , Zn 2+ ). We cited the literature which correlates the appropriate availability of trace elements as well as the functioning of nECM, with recall or memory. Due to limitations of space, we will not repeat the arguments and the cited references in our previous article. 7 Rather, below we summarize and expand on the underlying chemistry 8−27 and neuroelectric biology 28−38 of the tripartite mechanism, as it relates to the nECM with trace metals. 39−46 Definitions. The following terms are defined here for later discussions, as follows:• Tripartite System: Memory emerges from the dynamic interaction of three physiologic compartments: 1. Neurons 2. Neural extracellular matrix (nECM), enca...