Download Neurons in visual cortex

PLASTICITY AND POSTNATAL DEVELOPMENT
Key points
Early abnormal stimulation/activity leads to long-term functional deficits
(in vision these deficits may be called amblyopias)
Understand key features of receptive field transformations from retina through to cortex
Ocular dominance: contralateral (1), to binocular (4), to ipsilateral (7)
Developmental changes in neuronal structure and response properties
Understand the meaning of the critical or sensitive period in young postnatal animals
Knowledge of effects of visual deprivation on visual cortex
Effects of strabismus (squint), partial visual deprivation on visual function
Reading
Nolte (4th Ed), pgs 426-430
Fitzgerald, pgs 199-202
Centre/surround organisation of receptive fields in
retina and LGN
Non-orientation selective, non-direction selective, monocular
Neurons in visual cortex: Orientation selective, direction selective,
often binocular inputs, usually respond best to elongated contours
Morphological maturation of cortical neurons: development of
dendritic arbours, dendritic spines and synapses
Dendritic spines and synaptic density – changes with age
Binocular
Contra
Ipsi
Ocular dominance in cortex of normal and MD cats
Reverse
occlusion
Lateral geniculate nucleus
human
monkey
Monocular deprivation - monkey
Contra
Ipsi
Ocular dominance in cortex of strabismic cats
Partial visual deprivation – limited exposure to vertical orientations
Signalling molecules
and the critical period