Visually Guided Behaviour Flashcards
what does the geographical coordinate system require
radial coordinates to locate a point on a specifically defined sphere (ellipse)
P(x,y,z)
what is the azimuth
angle between the projected vector and a reference vector on the reference plane
what is a challenge in orientation
translating spherical 3D coordinates to 2D cartesian coordinates (pi)
2 vector components of visible light (part of EM spectrum)
E (electric)
H (magnetic)
visible light vibration
occurs in direction of propagation (z) 90 degrees apart
E vector interacts with matter
amplitude dimishes at 90 d, passes unhindered at 0 d
3 orientations of E vector vibrations
1) planar (vibrations along the geometric plane)
2) circular (amplitude precessing equally around the axis of propagation
3) elliptical (amplitude precessing unequally about the axis of propagation)
degree of polarisation
ranges from 0% (direct sunlight) to maximum 75% (90 d from sunlight)
spectral gradient
colour of the sky changes depending where you look relative to the sun
closer to the sun (green) (longer wavelength)
opposite to the sun (violet) (shorter wavelength)
moon/stars/milky way are used for navigation)
polarised light detection in arthropods
DRA (dorsal rim area) contains photoreceptor cells
microvilli are tuned to detect E vector cells
microvilli contains rhodopsin (maximal photon absorption for an E vector parallel to microvillar axis)
visual system layers
medulla
lamina
central complex of the insect brain
needed for navigation
contains:
protocerebral bridge (pb)
fan shaped body (fb)
ellipsoid body (eb)
noduli (no)
CPU1 neurons and LAL
in the central complex
sensory info translated to motor output
CPU1 neurons may be involved in integrating visual information with other sensory information, such as from the legs or antennae, to help the insect decide where to go.
lateral accessory lobe projects to the thalamus and relays to the BS
visual features
brightness and colour
optic flow
approaching objects
translating objects
(caused after seeing a visual scene)
responses to visual scenes
phototaxis
responses to approaching/translating objects
optomotor stabilisation
navigation
visual learning
visual inputs for orientation
contour/feature detection
motion detection
methods to measure contour/feature detection
expose to infrared light
use flight stopper/puffer
infrared sensor/sensitive camera
LED display
ellipsoid body
represents cartesian coordinates
contains rings R1-4
processing centre for visual information related to navigation
receives info from anterior optic pathway and relays visual data
define motion detection
the ability to distinguish moving stimuli from stationary ones and their direction of movement
how is motion detected
Luminence value (L) from 2 locations in visual space separated by distance dx and delayed in the time must be combined
motion detection models
hassenstein reichandt
barlow-levick
fully opponent HR
signal from one photoreceptor is delayed by temporal filter (E) and fed with instantaneous signal from the right photoreceptor into an excitatory non linearity
motion detection circuit in flies
R1-6 photoreceptors
L1/2 lamina cells
medulla cells
T4/T5 tangenital cells
LPTC (lobula plate tangenital cells)
motion detection in mice
cone cells
bipolar cells
ON/OFF SAC (starburst amacrine cells)
DSGC (direction-selective ganglion cells)
interconnectivity of the central complex
central complex gates brain output to segmental motor circuits (CPGs) of thoracic ganglia (in vertebrates its the SC)
