Glossary of Terms

Action Potential

The response by a neuron when its postsynaptic membrane potential reaches a threshold value, causing it to depolarize. In natural neurons, depolarization causes the vessicles in the axon to release chemicals (neurotransmitters) into their synaptic clefts, which are detected by the efferent neurons' receptors. In synthetic neurons, depolarization causes the efferent neurons to be evaluated and if they depolarize, their action potentials are scheduled for the following epoch.

Architecture

The set of Salient Attributes of a system that consistently supports its requirements, specification, design, implementation, test and maintenance (or in nature, expression). Architecture includes not only quantitative attributes, but also qualitative ones as well; i.e., the level of fidelity to which a standard is adhered to, etc. By way of example, a suspension bridge might have the requirement that it allow passage of boat traffic underneath. A floating bridge might not need to allow boat traffic to pass, but would need to be unsinkable. A salient attribute of the suspension bridge is that it can be made of suspendable materials. A salient attribute of the floating bridge is that it can float. The design of the suspension bridge might include being porous, to save weight, supporting its salient attribute, while the design of the floating bridge would not include being porous, because that would cause it to sink.

Behavior

We use the term behavior to describe organized movements, or sequences of organized movements, associated with an organism controlled by a brain. In synthetic organisms, such as virtual ones controlled by a synthetic brain, behavior may also include virtual movements, such as the navigation through the virtual world, or taking actions that have meaning in the virtual world, such as the production or editing of data, or the interaction with a computer system so as to control its operation or provide input. The term behavior does not apply to movements that are not organized or in any way coordinated; i.e., the random kicks and jerking of the limbs in a newborn human are not coordinated so as to collectively create locomotion, although over time, the kicks begin working together to ultimately achieve aggregate motion of the organism, which becomes behavior, as it becomes organized.

Brain

A set of interconnected neurons and their connections, whether natural or synthetic.

Cerebellum

The cerebellum is a major feature of the brain of all vertebrates, playing an important role in motor control and motor learning. In humans, the cerebellum does not actually initiate movement, but provides fine-tuned coordination and timing, offloading these more real-time aspects of movement from the cerebral cortex.

Connectome

An abstract representation of all of the components of a natural or synthetic brain, including its neurons and interconnections. Commonly represented as a directed cyclic graph.

Design

The definition of a system which describes how it will meet its specification. Suppose an hypothetical system is required to interact with people in many languages (a Requirement). Its Specification might dictate that the system display its text in those languages in the native character sets. The Design would define a method for displaying text in those character sets; i.e., with a font library that includes those fonts.

Deployment

In synthetic brain simulations, the provisioning of a simulation's server set with an instantiation of a model, including classes, nodes and their links, and I/O channels. The same model may be deployed to many server sets, creating multiple instances of the same sentience, each with its own history of interaction with its environment, and behavior.

Epoch

A discrete period of time during which all of the neurons in a synthetic brain simulation are evaluated and their state updated from activities since the previous epoch. As natural brains have action potentials that occur no more frequently than 1ms, this is a common lower bound timebase for the duration of an epoch. Synthetic brains interacting with slower environments may not need the same performance, and might use epochs of 10ms, 100ms, or even 1sec, conserving energy or increasing capacity.

Homeostatic Regulation

A process by which a system's overall functioning is up-leveled (increased) or down-leveled (decreased) through various mechanisms, each of which may be modulated independently. In the case of brains, overall alertness is an effect of a regulatory process, which may be emulated in a brain simulation.

Input Channel

A simulation's connection to its environment, physical or virtual, that allows external agents, such as robotic sensory devices, to stimulate the running simulation with data from the environment.

MISI

Model Input Signal Interface, the Sentience Engine's interface used to process input channel input.

Model

An abstract representation, often expressed in a modeling language, used as input to a simulator.

Modeling Language

A formal programming language used to describe a simulation model. NeuroSynthetica's modeling language SOMA™ includes class definitions for nodes, receptors, signals, as well as objects which contain nodes, arrays of nodes, and arrays of objects. Programmatic statements provide for using FOR, WHILE, and IF statements to describe algorithms by which the elements are wired together with efferent links.

MOSI

Model Output Signal Interface, the Sentience Engine's interface used to process output channel input.

Natural Brain

A brain built by nature; a multicellular organ consisting of a network of neurons and other supporting tissue.

Node

The simulation's representation of a neuron in the simulation space. A node has a fixed (x,y,z) coordinate in 3D node space, and is an instance of a node class, which defines the simulation behavior of nodes of that class. Nodes may have efferent links, which are connections to other nodes in the simulation, which are stimulated whenever their afferent node generates an action potential.

Output Channel

A simulation's connection to its environment, physical or virtual, that allows external agents, such as robotic sensory devices, to receive output from the running simulation, so that it may exhibit behavior in the environmental context.

Plasticity

One or more mechanisms through which a brain's functioning is adjusted in order to achieve a change in future processing. One example in nature is Hebbian learning, which causes the links of connected nodes that fire together, to increase their strength over time. In simulo, the algorithm which is used to implement this is commonly Spike Timing Dependent Plasticity, or STDP.

Requirement

The definition of a system which describes what the system needs to accomplish. Suppose an hypothetical system is required to interact with people in many languages (a Requirement). Its Specification might dictate that the system display its text in those languages in the native character sets. The Design would define a method for displaying text in those character sets; i.e., with a font library that includes those fonts.

Salient Attribute

A quality of a system that supports the Requirements, Specification, Design, and implementation (or in nature, expression) of the design.

Scientific Method

A commonly-used emperical method for acquiring knowledge based on the hypothesize and test paradigm. An inquiry begins with a question, such as "How does sentience arise?" An hypothesis or conjecture is made, such as "Perhaps sentience occurs when an animal eats oranges." An experiment is designed to test the hypothesis, where newborn animals are not fed oranges, and their sentience evaluated in an orange-less environment. The experiment is run and reveals a finding; namely, that some animals are sentient without having eaten oranges. The conclusion from the study is that the hypothesis is not true. Many similar experiments could rule out other foods and environments, gaining knowledge about sentience.

Sentience

Also, Sentience Effect. The effect that arises from a natural or synthetic brain when it senses the environment and elicits meaningful and relevant behavior responsive to the environment. For our purposes, sentience arises from general purpose structures not specifically designed to exhibit a certain behavior given a certain input stimulus.

Sentience Engine™ Simulator

NeuroSynthetica's real-time neural network simulator used to test, develop and deploy sentience in simulo. Sentience Engine™ is a trademark of NeuroSynthetica.

Server Set

A set of servers, each running a copy of the Sentience Engine™ simulator, that forms a logical computing cluster for hosting a simulation. Each server may have membership in more than one server set, and server sets may contain from one to 255 servers.

Simulation

A continuously-evaluated model of a brain running on a computer system or network of computer systems, emulating the physical processes performed by natural systems at a functional level.

SOMA™ Modeling Language

A formal programming language invented by NeuroSynthetica for use with its Workbench product. SOMA™ includes class definitions for nodes, receptors, signals, as well as objects which contain nodes, arrays of nodes, and arrays of objects. Programmatic statements provide for using FOR, WHILE, and IF statements to describe algorithms by which the elements are wired together with efferent links. SOMA™ is a trademark of NeuroSynthetica.

Specification

The definition of a system which describes what will be done to meet the requirements. Suppose an hypothetical system is required to interact with people in many languages (a Requirement). Its Specification might dictate that the system display its text in those languages in the native character sets. The Design would define a method for displaying text in those character sets; i.e., with a font library that includes those fonts.

Spiking Neural Network (SNN)

A neural network model consisting of nodes together with their interconnections, where the communication between nodes is not represented by static levels but by the temporal pattern of pulses.

Synthetic Brain

A brain not built by nature, but by a designer using CAD tools to build a model which is then run on a real-time simulator, normally connected to sensory apparatus and output devices capable of exhibiting behavior within the environment.

Synthetic Intelligence (SI)

Artificial intelligence through sentience, arising from a simulated synthetic model of the most minimal brain architecture necessary and sufficient for behavior to emerge. Synthetic Intelligence is the next evolution of Artificial Intelligence (AI), which includes a spectrum of classes of systems, including Expert Systems, Blackboard Systems, and Machine Learning.

Synthetic Sentience (SS)

The effect arising from a real-time simulation of a network of simulated spiking neurons, on a NeuroSynthetica Sentience Engine™ server. Like the sentience effect arising from the interaction of biological network of neurons and their real-time environment, Synthetic Sentience has no awareness that it is implemented by a continuous neural network simulation; it merely continuously self-trains its neural network through live interaction with its environment as the biological version does.

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