New Observations on the Organization and Evolution of the Telencephalon of Actinopterygian Fishes

Avoidance Response in Goldfish: Emotional and Temporal Involvement of Medial and Lateral Telencephalic Pallium

“…Thus, these cortical areas (close to the hippocampus) may be involved in nonspatial functions (i.e., temporal attribute processing). In our case, the lesions of the LP extended to the Dld, which has been proposed as homologous to the isocortex of tetrapods (Braford and Northcutt, 1974;Northcutt and Braford, 1980;Northcutt and Davis, 1983;Butler, 1994). Although further studies on the functional implications of the fish lateral pallium are necessary, our results present a thought-provoking scene in which the functional involvement of the teleost fish LP is discussed in functional and theoretical terms similar to those for hippocampal formation.…”

Amygdala and Emotional Learning in Vertebrates – A Comparative Perspective

“…Also, the deficit showed in both the acquisition and retention in avoidance behavior cannot be attributed to the lack of activity or initiative of the animal after lesion, because the level of escape is very high. In addition, the absence of effects on spatial memory or motor response (Portavella & Vargas, 2005) rules out a possible functional homology with the hippocampus and basal ganglia of tetrapods (Braford, 1995;Braford et al, 1992;Echteler & Saidel, 1981;Murakami et al, 1983;Nieuwenhuys & Verrijdt, 1983;Northcutt, 1995;Northcutt & Braford, 1980;Parent, 1986;Parent et al, 1978). Thus, we concluded that the lesion produced a deficit in the associative process between the discriminative stimulus and the shock (Portavella et al, 2002;2004a, 2004bPortavella & Vargas, 2005;Vargas et al, 2009).…”

“…In actinopterygians, the telencephalon undergoes an eversion process that raises a serious difficulty in establishing homologies with the amygdala (Braford, 1995;Gage, 1983;Scalia & Ebbesson, 1971). However, the cytoarchitecture, the neurohistochemistry, studies of embryonic development, the pattern of connectivity and topological studies (Braford, 1995;Chanconie & Clairambault, 1975;Morgan, 1974aMorgan, , 1974bMurakami et al, 1983;Northcutt, 1981;Northcutt & Braford, 1980) suggest that the region Dmv of the teleost telencephalon is a good candidate to be considered the homologue of the pallial amygdala (Northcutt, 1995;Northcutt & Braford, 1980), although other authors suggest that Dmv could be homologous to the basal ganglia or the hippocampus of mammals (Murakami et al, 1983;Parent et al, 1978). Moreover, the pattern of connectivity, with strong sensory thalamic inputs and reciprocal connections with the hypothalamus, gives a distinctly limbic character to Dmv (Braford, 1995;Echteler & Saidel, 1981;Ito et al, 1986;Murakami et al, 1983;Striedter, 1991).…”

“…This data is also supported by functional data as damage to this structure affects the male reproductive behavior and other signs of social interest such as parental care or aggressive behavior, the same pattern of deficits that is found with lesions of the corticomedial amygdala in mammals (Isaacson, 1976;Kling & Brothers, 1992). In fact, it has been proposed that the most medial region of the ventral area of the telencephalon in teleosts fish correspond to the subpallial amygdala (Northcutt, 1995;Northcutt & Braford, 1980).…”

Hippocampal Pallium and Map-Like Memories through Vertebrate Evolution

“…As a consequence, the telencephalic hemispheres of ray-finned fishes lack internal ventricles and the medial-to-lateral topography of the pallial areas is reversed compared with that observed in every other vertebrate. Accordingly, the actinopterygian pallial area considered homologous to the hippocampus is located laterally in the telencephalon [55] [57]- [60].…”