Manatee tactile hairs: Manatees possess specialized tactile bristles and hairs which are distributed over the entire body surface. We hypothesize that Sirenia have developed a mammalian version of the lateral line system which detects water currents, approaching animals and other stimuli producing underwater mechanovibratory signals not detectable through the auditory system. In collaboration with colleagues Dr. Gordon Bauer (New College) and Dr. David Mann (University of South Florida), graduate student Joe Gaspard is performing behavioral experiments on two captive manatees at Mote Marine Laboratory to investigate the functional capacity of this system.
Manatee brain and body growth: Adult manatees have small brains relative to their body size, when compared to other mammals. However, this may reflect prolonged body growth rather than diminished brain size per se. Graduate student Alex Costidis is investigating growth dynamics of brain and body in Florida manatees, and performing a comparative analysis to determine if manatees exhibit prolonged body growth compared to other similarly sized marine mammals.
Manatee brain pathways: We are using postmortem axonal tracing (DiI) to investigate neural connections among regions of the brainstem and thalamus that process tactile information. Understanding this organization will allow us to gain further insight into the means by which information from the tactile hairs travels in the manatee brain.
Rodent model of hemispatial neglect: Neglect occurs in humans after cortical infarct in a high percentage of cases of right hemisphere stroke. Over the past 25 years, we have collaborated with Dr. Jim Corwin at Northern Illinois University to develop a rat model to investigate the circuitry and pharmacology mediating directed attention and its dysfunctional state, contralateral neglect, and to explore potential therapies for inducing neural repair and functional recovery. Normal directed attention is mediated by circuitry involving specific areas of cerebral cortex, striatum and thalamus. Currently, undergraduate students Billy Conte, Tamara Stiep and Tobias Schmid are investigating neuronal connections of the lateral posterior thalamic nucleus and cerebral cortical areas AGm and PPC, part of the circuitry related to neglect. These studies involve the use of axonal tracers and image analysis.