Afferent connectivity to different functional zones of the optic tectum in goldfish

Abstract

This work studies the afferent connectivity to different functionally identified tectal zones in goldfish. The sources of afferents contributed to different degrees to the functionally defined zones. The dorsocentral area of the telencephalon was connected mainly with the ipsilateral anteromedial tectal zone. At diencephalic levels, neurons were found in three different regions: preoptic, thalamic, and pretectal. Preoptic structures (suprachiasmatic and preoptic nuclei) projected mainly to the anteromedial tectal zone, whereas thalamic (ventral and dorsal) and pretectal (central, superficial, and posterior commissure) nuclei projected to all divisions of the tectum. In the mesencephalon, the mesencephalic reticular formation, torus longitudinalis, torus semicircularis, and nucleus isthmi were, in the anteroposterior axis, topographically connected with the tectum. In addition, neurons in the contralateral tectum projected to the injected zones in a symmetrical point-to-point correspondence. At rhombencephalic levels, the superior reticular formation was connected to all studied tectal zones, whereas medial and inferior reticular formations were connected with medial and posterior tectal zones. The present results support a different quantitative afferent connectivity to each tectal zone, possibly based on the sensorimotor transformations that the optic tectum carries out to generate orienting responses.

Afferents of the lamprey optic tectum with special reference to the GABA input: Combined tracing and immunohistochemical study

“…Afferent projections from both the ventral and the dorsal thalamus to different tecal zones have been reported in fish (Grover and Sharma, 1981;Luiten, 1981;Northcutt, 1982;Smeets, 1982;Fiebig et al, 1983;Schlussman et al, 1990;Pérez-Pérez et al, 2003) and other vertebrates (Grofova et al, 1978;Dacey and Ulinski, 1986;Taylor et al, 1986;Zittlau et al, 1988) and agree with the direct thalamotectal projections found in the lamprey. A recent report on larvae lamprey also describes projections from different thalamic nuclei to the tectum (De Arriba et al, 2004).…”

“…Projections from pretectal nuclei to the tectum are generalized across vertebrates (Northcutt, 1982;Smeets, 1982;Cadusseau and Roger, 1985;Lugo-Garcia and Kicliter, 1988;Zittlau et al, 1988;Rettig, 1988;Medina and Smeets, 1991;Pérez-Pérez et al, 2003). In the present study, we show that also in the lamprey there is a robust afferent projection to the tectum from the contralateral pretectum.…”

Integrated Brain Diversification along the Early Neuraxes

“…The function of the mesencephalon is to receive inputs from the eyes; it then passes information to the dorsal thalamus, which relays information to the pallium for processing ( fig. 4 c) [Perez-Perez et al, 2003;Broglio et al, 2005]. WNT signals function along the AP neuraxis throughout ontogeny to specify these structures, regulate their growth by controlling proliferation during neurogenesis, and promote neural connections once these structures are functional [Panhuysen et al, 2004;Joksimovic et al, 2009].…”

Gene expression correlates of social evolution in coral reef butterflyfishes

“…In pair bonding butterflyfish, both olfactory and visual cues are used for conspecific recognition 132 and are necessary to modulate relationships with partners, territorial intruders 133 and competitors for mates 134 . In teleosts, the ventral telencephalon is the major target of olfactory projections [135][136][137] , but not of optic neurons, nor is it innervated with the optic tectum [138][139][140] , the major brain region in which visual information is integrated and processed in vertebrates 141 . Taken together, we speculate that in C. lunulatus females, V1aR and ITR activation within the Vv/Vl might enhance conspecific recognition via olfactory perception 42 .…”