What are the functions of fish brain pallium?

How do individuals cope with stress? Behavioural, physiological and neuronal differences between proactive and reactive coping styles in fish

“…Notably, regional differences in 5-HT 1A transcript abundance are important as these results support the notion that differential 5-HT receptor distribution in neuronal networks (at least partially) determines active and passive coping strategies (Puglisi-Allegra and Andolina, 2015). Proactive fish responded to the stressor with increased bdnf mRNA abundance in the Dl, which is the proposed hippocampus homologue (Goodson and Kingsbury, 2013;O'Connell and Hofmann, 2011;Vargas et al, 2009), and the Vv. Synaptic plasticity is promoted by bdnf, as are neurogenesis, cell survival and the strengthening of learning and memory (Mattson et al, 2004).…”

“…Interestingly, the lack of a 6-layered pallium does not imply an absence of so-called 'higher functions', and telencephalic cortical-like functions have been reported in several fish species (Bshary and Brown, 2014;Demski, 1983;Grosenick et al, 2007;Ito et al, 2007;Ocaña et al, 2015). The fish's dorsomedial (Dm) and dorsolateral (Dl) pallium have been characterised as functional homologues of the mammalian amygdala and hippocampus, respectively, and are implicated in stimuli salience, memory and learning (Goodson and Kingsbury, 2013;O'Connell and Hofmann, 2011;Vargas et al, 2009). Furthermore, in terms of stimuli salience and emotional coding, the mammalian lateral septum appears to work in conjunction with the amygdala and hippocampus to regulate emotional reactivity and goal-oriented behaviour, respectively (Luo et al, 2011;Singewald et al, 2011).…”

Amygdala and Emotional Learning in Vertebrates – A Comparative Perspective

“…Likewise, though being intrinsically a very complex structure (Amaral et al, 1992;Pitkänen et al, 1997), it is clear that lesions of a large part of the nucleus of the pallial amygdala (basolateral amygdala) and also the subpallial part seriously affect all type of emotional learning. In fish, the ablation of Dmv telencephalon induced a clear deficit in a conditioned avoidance behavior, similar to that produced after a complete ablation of the telencephalon (Portavella et al, 2004a(Portavella et al, , 2004bPortavella & Vargas, 2005;Vargas et al, 2009). These data coupled with the effects of Dm lesions on aggressive behavior, breeding, habituation in situations of aggression in a resident/intruder paradigm (de Bruin, 1980;Marino-Neto & Sabbatini, 1983), as well as data from electrical stimulation of Dm in Carassius that show facilitation and inhibition of aggressive and reproductive patterns or startle response and escape (Savage, 1971), support the homology of the fish telencephalic Dmv with the pallial amygdala of mammals.…”

“…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). Other results in fear context conditioning have showed that lesions of the dorsomedial telencephalic portion in Betta splendens produced a facilitation of habituation to the context (Marino-Neto & Sabbatini, 1983) and variations in levels of aggression (de Bruin, 1980).…”

“…The other one is the association between the CS and the shuttling response (Zhuikov et al, 1994). Given these results, it could be postulated that the lesion in the dorsomedial region deprives the fish of such capacity, and it would be one of the causes of the main deficit for the maintenance of avoidance behavior (Portavella et al, 2002;2004a, 2004bPortavella & Vargas, 2005;Vargas et al, 2009). …”