Alphabetical list

Independent efffector ( Parker, 1909 ) : A non-neuronal cell (Hooke, 1665) producing a response like contraction or secretion without input from a neuron (Waldeyer, 1891); p. 56. See effector (Sherrington, 1906). more details

Inferior ( Vicq d'Azyr, 1786 ) : He defined it as below, or toward the plane on which the body is supported; pp. 51, 87; also see Standring (2008, p. xxii) and posterior (Aristotle). more details

Initial segment ( Palay, 1964 ) : Typically the narrowest segment of the axon trunk, just distal (Barclay, 1803) to the axon hillock (Schaffer, 1893), where action potentials are typically generated; p. 86; term also used by Herndon (1963, p. 170). Also see Palay et al. (1968) and Strong & Elwyn (1925, Fig. 136). more details

Inner ( Galen, c173 ) : Closer to the center of an object in the body; the opposite of outer; see Standring (2008, p. xxii). The dichotomy was used at least as far back as Galen in the second century; see, for example, translations by May (1968, pp. 711, 377) and Singer (1999, p. 131). Aristotle wrote in De Partibus Animalium of parts within the body and those placed on the outside; see translation by Ogle (1912, 674, 5-6). more details

Input : A connection to a neuron (Waldeyer, 1891), neuron type (Bota & Swanson, 2007), or gray matter region from another neuron, neuron type, or gray matter region. All such nodes can and generally do have multiple inputs. more details

Interbrain ( IB ; Baer, 1837 ) : The caudal (Cleland, 1879) and ventral (Schulze, 1893) topographic division of the forebrain (Goette, 1873); the rostral (Schulze, 1893) and dorsal (Barclay, 1803) division is the endbrain (Kuhlenbeck, 1927). The interbrain in turn has two great topographic divisions, dorsally (Barclay, 1803) the thalamus (His, 1893a) and ventrally (Schulze, 1893) the hypothalamus (Kuhlenbeck, 1927). This basic division of the macrodissected adult human brain (Edwin Smith Surgical Papyrus, c1700 BC) has been recognized at least since Varolio (1573, p. 13, his "pars posterior medullae spinalis"), and it received its current name for vertebrates from Baer (1837, p. 107; in the original German, "Zwischenhirn"). This English form of diencephalon (Sharpey et al., 1867) has been used routinely, for example by Sharpey et al. (1867, p. 577), Johnston (1906, p. 25), Strong & Elwyn (1943, p. 12), and Williams & Warwick (1980, p. 953). more details

Internal : Synonym for inner (Galen, c173). The term was used by Aristotle in De Partibus Animalium; see translation by Ogle (1912, e.g., 685b-25); also see Barclay (1803, p. 116), Standring (2008, p. xxii). more details

Internodal connection : A connection between two nodes. more details

Interregional connection : A connection between two gray matter regions, as compared to an intraregional connection, which remains within a single gray matter region. It can be an interregional macroconnection, mesoconnection, or microconnection. more details

Interregional pathway : A pathway between two gray matter regions, as compared to an intraregional pathway, which remains within a single gray matter region. It can be an interregional macropathway, mesopathway, or micropathway. more details

Intranodal connection : For macroconnections (Thompson & Swanson, 2010) an intraregional connection, for mesoconnections (Thompson & Swanson, 2010) a connection that feeds back onto the neuron type (Bota & Swanson, 2007) that generates it (a connection from neuron type z to neuron type z), and for microconnections (Thompson & Swanson, 2010) a connection that feeds back onto the neuron (Waldeyer, 1891) that generates it (a connection from neuron z to neuron z). more details

Intranodal pathway : For macropathways an intraregional pathway, for mesopathways a pathway that feeds back onto the neuron type (Bota & Swanson, 2007) that generates it (a pathway from neuron type z to neuron type z), and for micropathways a pathway that feeds back onto the neuron (Waldeyer, 1891) that generates it (a connection from neuron z to neuron z). more details

Intraregional connection : A connection that arises and terminates within a particular gray matter region, as compared to an interregional connection, which extends between two gray matter regions. It can be an intraregional mesoconnection or microconnection. more details

Intraregional pathway : A pathway that arises and terminates within a particular gray matter region, as compared to an interregional pathway, which extends between two gray matter regions. It can be an intraregional mesopathway or micropathway. more details

Intrinsic connection : Often a synonym for intraregional connection, though its meaning can be vague and its use is thus discouraged. more details

Intrinsic pathway : Often a synonym for intraregional pathway, though its meaning can be vague and its use is thus discouraged. more details

Invertebrate brain ( BRi ) : The most rostral (Schulze, 1893), largest, most differentiated central ganglion of a central nerve cord (or ganglia if multiple cords are involved); see Bullock & Horridge (1965, pp. 542-550). Cuvier (1800, lecture 11) explicitly discussed invertebrates and their brains without using the term itself. more details

Invertebrate nerves : Nerves (Herophilus, c335-280 BC) of the invertebrate peripheral nervous system (Meckel, 1817); see Bullock & Horridge (1965). more details

Invertebrate peripheral ganglia : Ganglia (Galen, c173) of the invertebrate peripheral nervous system (Meckel, 1817); see Bullock & Horridge (1965). more details

Ipsilateral : On the same side of the body in an animal with bilateral symmetry; see Standring (2008, p. xxii). more details