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Gaspard III, J. C., Bauer, G. B., Mann, D. A., Boerner, K., Denum, L., Frances, C., & Reep, R. L. (2017). Detection of hydrodynamic stimuli by the postcranial body of Florida manatees (Trichechus manatus latirostris) A Neuroethology, sensory, neural, and behavioral physiology. Journal of Comparative Physiology, 203, 111-120. doi:10.1007/s00359-016-1142-8.
Abstract
Manatees live in shallow, frequently turbid
waters. The sensory means by which they navigate in these
conditions are unknown. Poor visual acuity, lack of echo-
location, and modest chemosensation suggest that other
modalities play an important role. Rich innervation of sen-
sory hairs that cover the entire body and enlarged soma-
tosensory areas of the brain suggest that tactile senses are
good candidates. Previous tests of detection of underwater
vibratory stimuli indicated that they use passive movement
of the hairs to detect particle displacements in the vicinity
of a micron or less for frequencies from 10 to 150 Hz. In
the current study, hydrodynamic stimuli were created by
a sinusoidally oscillating sphere that generated a dipole
field at frequencies from 5 to 150 Hz. Go/no-go tests of
manatee postcranial mechanoreception of hydrodynamic
stimuli indicated excellent sensitivity but about an order of
magnitude less than the facial region. When the vibrissae
were trimmed, detection thresholds were elevated, suggest-
ing that the vibrissae were an important means by which
detection occurred. Manatees were also highly accurate in two-choice directional discrimination: greater than 90%
correct at all frequencies tested. We hypothesize that mana-
tees utilize vibrissae as a three-dimensional array to detect
and localize low-frequency hydrodynamic stimuli -
Tyler-Julian, K., Chapman, K. M., Frances, C., & Bauer, G. B. (2016). Behavioral lateralization in the Florida manatee (Trichechus manatus latirostris). International Journal of Comparative Psychology, 29. Retrieved from https://escholarship.org/uc/item/1hg3g3vt.
Abstract
We examined side preferences in the Florida manatee (Trichechus manatus latirostris) through observations of limb use (right and left flipper) in 123 wild and 16 captive individuals. We also analyzed archival data, the United States Geological Survey Sirenia ProjectManatee Individual Photo-identification Systemdataset, to determine lateralization of evasive action from boats. Wild and captive manatees displayed flipper lateralization at the individual, but not the population level for several behaviors including substrate touches, sculling, and feeding. In contrast, manatees were lateralized at the population level for boat-scar biases,with more manatees showing a left scar bias (45.3%) versus right (34.3%) or dorsal/ambipreferent (20.3%). -
Nomi, J. S., Frances, C., Nguyen, M. T., Bastidas, S., & Troup, L. J. (2013). Interaction of threat expressions and eye gaze: an event-related potential study. NeuroReport, 24, 813-817. doi:10.1097/WNR.0b013e3283647682.
Abstract
he current study examined the interaction of fearful, angry,
happy, and neutral expressions with left, straight, and
right eye gaze directions. Human participants viewed
faces consisting of various expression and eye gaze
combinations while event-related potential (ERP) data
were collected. The results showed that angry expressions
modulated the mean amplitude of the P1, whereas fearful
and happy expressions modulated the mean amplitude of
the N170. No influence of eye gaze on mean amplitudes for
the P1 and N170 emerged. Fearful, angry, and happy
expressions began to interact with eye gaze to influence
mean amplitudes in the time window of 200–400 ms.
The results suggest early processing of expression
influence ERPs independent of eye gaze, whereas
expression and gaze interact to influence later
ERPs.
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