Node (in neurocognitive linguistics)
Node in neurocognitive linguistics has two senses, both of which are defined in this article:
- Node as used in compact relational network notation.
- Node as used in narrow relational network notation.
In Compact Notation
A node is any point at which lines meet. At each such point in relational network modeling, the type of node must be identified. Nodes used in this form of relational network notation differ from one another according to three dimensions of contrast:
- Upward vs. downward orientation. Downward is toward expression. Upward is toward meaning or function. For example, a lexicogrammatical node might point upward toward the sememic stratum or downward toward the phonological.
- AND vs. OR.
- Ordered vs. unordered.
Node types are also distinguished from one another on the basis of how they treat incoming activation.
Each node has a singular side to which one line is connected, and a plural side to which two or more lines connect. With a few exceptions, nodes in compact notation are bidirectional, capable of carrying activation in either direction.
Another type of node is the tactic connector, also known as a diamond node.
In Narrow Notation
A node in narrow notation is part of an account of the internal structure of a node of compact notation. The one-way nodes in narrow notation are of two types:
- The branching node, in which activation branches out from the singular side to the plural side.
- The junction node, in which activation comes from one or more lines on the plural side and may continue on the singular side.
The AND/OR difference is represented in narrow notation as a difference in threshold. (Cf. threshold node.) Narrow notation has no distinction between ordered and unordered nodes; an account of ordering is provided by combinations of narrow elements, including additional ones, like inhibitory connections.
- Lamb, Sydney M.. 1999. Pathways of the Brain: The Neurocognitive Basis of Language. Philadelphia: John Benjamins.