Visually Guided Behaviour

Question 1

what does the geographical coordinate system require

Answer 1

radial coordinates to locate a point on a specifically defined sphere (ellipse)
P(x,y,z)

Question 2

what is the azimuth

Answer 2

angle between the projected vector and a reference vector on the reference plane

Question 3

what is a challenge in orientation

Answer 3

translating spherical 3D coordinates to 2D cartesian coordinates (pi)

Question 4

2 vector components of visible light (part of EM spectrum)

Answer 4

E (electric)
H (magnetic)

Question 5

visible light vibration

Answer 5

occurs in direction of propagation (z) 90 degrees apart
E vector interacts with matter
amplitude dimishes at 90 d, passes unhindered at 0 d

Question 6

3 orientations of E vector vibrations

Answer 6

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)

Question 7

degree of polarisation

Answer 7

ranges from 0% (direct sunlight) to maximum 75% (90 d from sunlight)

Question 8

spectral gradient

Answer 8

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)

Question 9

polarised light detection in arthropods

Answer 9

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)

Question 10

visual system layers

Answer 10

medulla
lamina

Question 11

central complex of the insect brain

Answer 11

needed for navigation

contains:
protocerebral bridge (pb)
fan shaped body (fb)
ellipsoid body (eb)
noduli (no)

Question 12

CPU1 neurons and LAL

Answer 12

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

Question 13

visual features

Answer 13

brightness and colour
optic flow
approaching objects
translating objects

(caused after seeing a visual scene)

Question 14

responses to visual scenes

Answer 14

phototaxis
responses to approaching/translating objects
optomotor stabilisation
navigation
visual learning

Question 15

visual inputs for orientation

Answer 15

contour/feature detection
motion detection

Question 16

methods to measure contour/feature detection

Answer 16

expose to infrared light
use flight stopper/puffer
infrared sensor/sensitive camera
LED display

Question 17

ellipsoid body

Answer 17

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

Question 18

define motion detection

Answer 18

the ability to distinguish moving stimuli from stationary ones and their direction of movement

Question 19

how is motion detected

Answer 19

Luminence value (L) from 2 locations in visual space separated by distance dx and delayed in the time must be combined

Question 20

motion detection models

Answer 20

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

Question 21

motion detection circuit in flies

Answer 21

R1-6 photoreceptors
L1/2 lamina cells
medulla cells
T4/T5 tangenital cells
LPTC (lobula plate tangenital cells)

Question 22

motion detection in mice

Answer 22

cone cells
bipolar cells
ON/OFF SAC (starburst amacrine cells)
DSGC (direction-selective ganglion cells)

Question 23

interconnectivity of the central complex

Answer 23

central complex gates brain output to segmental motor circuits (CPGs) of thoracic ganglia (in vertebrates its the SC)