learning. This limits the effectiveness of a phylogenetic analysis (Fitch
2000). Nevertheless, computational problems are shared by all biological
systems that exhibit vocal learning, which may result in similar mechanistic solutions (Margoliash 2001). The following section describes production
and perception of song in relation to various pathways in the avian song
system.
2.3.3. Production-Perception Linkages in Birdsong
The bird song system provides an experimental model system amenable to
detailed neurobiological approaches with which to pursue questions of production/perception linkages in the context of a learned vocalization. Comparisons of neural responses to conspecific songs with responses to a bird’s
own song(s) explore the hypothesis that a bird’s own song holds a position
of particular perceptual significance within the representational system.
This hypothesis is well-supported by a variety of data. For instance, several
field playback studies demonstrate that aggressive responses from territorial males are often dependent on whether the particular playback song is
similar to one that the subject sings (see Owings and Morton 1998). In most
species, playback of the individual’s own song elicits a level of aggressive
response intermediate to the weakly aggressive responses to songs of
established neighbors and strongly aggressive responses to unfamiliar
(strangers’) songs (Stoddard 1996). The salience of a bird’s own song is also
apparent under more controlled conditions, as for example when examining acquisition rates or category formation in operantly trained tasks (Cynx
and Nottebohm 1992; Gentner and Hulse 1998) or behavioral preferences
(Pytte and Suthers 1999; Okanoya et al. 2000). Together, such data suggest
that some form of coupling exists between the song-production and
perception systems.
2.3.3.1. The Vocal Motor Pathway
The extensive analysis of the avian song system provides a basis for understanding how different components of the system contribute to perceptive
and productive components of behavior. Several forebrain pathways have
been identified as components of the song system, of which two have been
extensively analyzed (Fig. 7.3). A vocal motor pathway (VMP) is required
for song production, participates in moment-to-moment control of singing,
and represents the descending motor outflow of the forebrain song system.
An anterior forebrain pathway (AFP) shares similarities with the mammalian corticothalamo-basal ganglia loop. The AFP is required for normal
song development and may be necessary for adult song maintenance,
although contributing little (depending on species) to moment-to-moment
control of singing. The relative contributions, if any, of the VMP and AFP
to components of perceptual processing of conspecific songs would represent different schemes for establishing perception/production linkages, a
7. Neuroethology of Vocal Communication
345
2000). Nevertheless, computational problems are shared by all biological
systems that exhibit vocal learning, which may result in similar mechanistic solutions (Margoliash 2001). The following section describes production
and perception of song in relation to various pathways in the avian song
system.
2.3.3. Production-Perception Linkages in Birdsong
The bird song system provides an experimental model system amenable to
detailed neurobiological approaches with which to pursue questions of production/perception linkages in the context of a learned vocalization. Comparisons of neural responses to conspecific songs with responses to a bird’s
own song(s) explore the hypothesis that a bird’s own song holds a position
of particular perceptual significance within the representational system.
This hypothesis is well-supported by a variety of data. For instance, several
field playback studies demonstrate that aggressive responses from territorial males are often dependent on whether the particular playback song is
similar to one that the subject sings (see Owings and Morton 1998). In most
species, playback of the individual’s own song elicits a level of aggressive
response intermediate to the weakly aggressive responses to songs of
established neighbors and strongly aggressive responses to unfamiliar
(strangers’) songs (Stoddard 1996). The salience of a bird’s own song is also
apparent under more controlled conditions, as for example when examining acquisition rates or category formation in operantly trained tasks (Cynx
and Nottebohm 1992; Gentner and Hulse 1998) or behavioral preferences
(Pytte and Suthers 1999; Okanoya et al. 2000). Together, such data suggest
that some form of coupling exists between the song-production and
perception systems.
2.3.3.1. The Vocal Motor Pathway
The extensive analysis of the avian song system provides a basis for understanding how different components of the system contribute to perceptive
and productive components of behavior. Several forebrain pathways have
been identified as components of the song system, of which two have been
extensively analyzed (Fig. 7.3). A vocal motor pathway (VMP) is required
for song production, participates in moment-to-moment control of singing,
and represents the descending motor outflow of the forebrain song system.
An anterior forebrain pathway (AFP) shares similarities with the mammalian corticothalamo-basal ganglia loop. The AFP is required for normal
song development and may be necessary for adult song maintenance,
although contributing little (depending on species) to moment-to-moment
control of singing. The relative contributions, if any, of the VMP and AFP
to components of perceptual processing of conspecific songs would represent different schemes for establishing perception/production linkages, a
7. Neuroethology of Vocal Communication
345