7&8 - Stimulus Recognition I&II Flashcards
What must we do in order to understand visual recognition?
- Find single neurones that specifically respond to presentation of specific objects and understand their pre-synaptic neuronal circuits.
What is orientation invariance?
Being able to recognise an object regardless of the orientation.
What is scale invariance?
Being able to recognise an object regardless of size.
What can lesion in the inferior temporal cortex cause?
A decrease in the ability to recognise objects
How are lesions in the temporal cortex studied?
By modelling and electrophysiology.
What is the lateral geniculate nucleus (LGN)?
- A thalamic relay station
- Has 6 layers which alternate input from each eye.
- Parvo and magnocellular cells input here
How are cells in the LGN organised?
Retinopically
What are receptive fields of the LGN similar to?
The receptive fields of retinal ganglion cells.
What is back propagation?
60% of the synaptic input from the cortex going to the LGN.
What are 2 key features of the cortical structure?
- Layering
- Columns - ocular dominance, orientation, direction and Blobs
Where do the ocular dominance columns receive their input from?
From either an ipsilateral or contralateral eye.
What are blobs responsible for?
The processing of colour, they are not orientation selective.
Where do blobs receive their input from?
Parvocellular cells of the lateral geniculate nucleus.
Where are simple cells localised?
In layers 4-6
When do simple cells respond to a stimulus?
When it hits the middle of the receptive field
