Although these findings indicate that the spinomedullary tegmentum (SN) modulates light information as it passes from the retina to the visual center (vz), the precise mechanisms underlying these effects are not well understood. Besides being an important part of the neural circuitry underlying the circadian system, the SN is also involved in the control of sleep states, body temperature, and arousal mechanisms. In support of the latter hypothesis, connections of the SN to the locus coeruleus, the hypothalamus, and the brainstem reticular formation have been described. The SN has been implicated in the modulation of photic inputs to visual centers (vz), because of its marked light responsiveness. Our aim was to determine whether the selective activities of the SN neurons have any repercussions on visual-related plasticity, in order to enhance the understanding of the mechanisms underlying the influence of the SN on brain reorganization.
Based on the findings from neuroimaging and neurophysiological studies, the SN is involved in the modulation of light information. This is achieved by inducing sleep-state-related changes, or awake periods, through cholinergic projections of the SN or by the inhibition of the wake-promoting system. Synaptic plasticity in the visual system is the neural basis of visual learning and memory. We used an ocular imaging system to study the plasticity and apparent organization of visual regions in the seahorse (Hippocampus regius) in relation to its social behavior. We established the existence of phase shifts in the eyes of seahorses tested in isolation by recording the visual activity in females in response to a moving striped object. The temporal changes in the response of the seahorses were studied in order to find out whether the seahorses were able to change their response depending on their state of sleepiness. Little organization was shown in the neural projections of the seahorses tested in isolation, and there was no correlation between the distribution of visual projections and circadian rhythmicity. There was an apparent interaction between the neural projections and the social con- nection patterns between partners, and both the temporal and distribution of neural response in the visual system were significantly correlated with the spatio-temporal order of social behavior. These findings show that the visual system changes based on social cues and that the behavioral coordination of partners seems to be the basis of visual organization in the seahorse. d2c66b5586