Post-traumatic epilepsy (PTE) occurs in 20% of individuals with acquired epilepsy, and can impact significantly the quality of life due to the seizures and other functional or cognitive and behavioral outcomes of the traumatic brain injury (TBI) and PTE. There is no available antiepileptogenic or disease modifying treatment for PTE. Animal models of TBI and PTE have been developed, offering useful insights on the value of inflammatory, neurodegenerative pathways, hemorrhages and iron accumulation, calcium channels and other target pathways that could be used for treatment development. Most of the existing preclinical studies test efficacy towards pathologies of functional recovery after TBI, while a few studies are emerging testing the effects towards induced or spontaneous seizures. Here we review the existing preclinical trials testing new candidate treatments for TBI sequelae and PTE, and discuss future directions for efforts aiming at developing antiepileptogenic and disease-modifying treatments.

Defense and social mechanisms in primates seem to share, at least in infancy, common neural substrata.Among these, recent research has implicated the primate superior colliculus (SC) on tasks involving visual detection and recognition of threatening stimuli, such as snakes and faces with emotional expressions. There is also evidence that both kinds of stimuli share specific characteristics and command special attention in the primate visual system. The present review focuses on the role of the SC in these seemingly overlapping functions.We present social behavioral data from capuchin monkeys in which the bilateral lesion of the SC induced a transitory impairment of social behaviors. The findings presented here are compared with previous studies, our own and others, on social behaviors and threat detection. We argue that, although the SC may participate in both systems,its role is more prominent in the detection/recognition of threat. Social interactions more likely depend on larger and more complex neural systems, where the SC may play a key role in early infancy. The implications of these recent findings are discussed under an evolutionary perspective.

Electrophysiological and molecular genetic studies have shown that howler monkeys (Alouatta) are unique among all studied platyrrhines: they have the potential to display trichromatic color vision among males and females. This study examined the color discrimination abilities of four howler monkeys (Alouatta caraya) through a series of tasks involving a behavioral paradigm of discrimination learning. The animals were maintained and housed as a group in the Zoological Gardens of Brasília and were tested in their own home cages. Stimuli consisting of pairs of Munsell color chips were presented in random brightness values to assure that discriminations were based on color rather than brightness cues. All the animals (three males, one female) successfully discriminated all the stimulus pairs, including those that would be expected to be difficult for a dichromatic monkey. These results are consistent with the earlier predictions suggesting that howler monkeys are routinely trichromatic.

Prepulse inhibition (PPI) is the decrease of startle reflex amplitude when a slight stimulus is previously generated. This paradigm may provide valuable information about sensorimotor gating functionality. Here we aimed at determining the inhibited and uninhibited startle response of capuchin monkeys (Sapajus spp.), and to evaluate the role of the superior colliculus in PPI. Capuchin monkeys were tested in a whole-body protocol, to determine the best startle amplitude and interstimuli interval. Additionally we tested two subjects with bilateral superior colliculus damage in this protocol. Results show that 115 dB auditory pulse has induced the best startle response. In contrast to reports in other species, no habituation to the auditory stimuli was observed here in capuchins. Also, startle reflex inhibition was optimal after 120 msec interstimuli interval. Finally, there was a downward tendency of percentage inhibition in superior colliculus-lesioned monkeys. Our data provides the possibility of further studies with whole-body protocol in capuchin monkeys and reinforces the importance of the superior colliculus in PPI.

Dizocilpine (MK-801) is a non-competitive NMDA antagonist that induces schizophreniclike effects. It is therefore widely used in experimental models of schizophrenia including prepulse inhibition (PPI) impairments in rodents. Nevertheless, MK-801 has never been tested in monkeys on a PPI paradigm. In order to evaluate MK-801 effects on monkeys’ PPI, we tested eight capuchin monkeys (Sapajus spp.) using three different doses of MK-801 (0.01; 0.02; 0.03 mg/kg). Results show PPI impairment in acute administration of the highest dose (0.03 mg/kg). PPI impairment induced by MK-801 was reversed by re-exposure to the PPI test throughout treatment trials, in contrast with rodent studies. These results indicate that tolerance effect and familiarization with PPI test may reduce the sensorimotor gating deficits induced by MK-801 in monkeys, suggesting a drug-training interaction.