Lecture 10 Flashcards
Why can the brain be affected weirdly by damage?
The brain is very modular, damage can affect us in weird ways (such as being able to see where an object is, but not being able to recognise it).
What is sensation?
Sensation is the act of recieving information from the outside world, it is done by various receptors in order to transform the information into a form the brain can use.
What is perception?
Perception is interpreting information that comes into the brain.
What are the steps in neural implementation?
The neural implementation steps are:
Step1: sensory organs absorb energy.
Step2: energy is transduced into a neural signal.
Step3: the neural signal is sent throughout the brain where further processing takes place (e.g another neuron detects edges or colours).
This means perception and sensation are interlinked processes, which perception occuring more in later neurons.
What is the visible range roughly and what are the two main parts for vision?
The visible range is from roughly 380 nm to 740 nm wavelengths of light. This tells us what colour the object is, the amplitude tells us whether it is bright or dim.
What are the main parts of the eye?
The eye’s outer layer is the cornea which helps focus light from outside onto the back of the retina. The middle layer is the choroid, this produces fluid which provides nutrients to the eye to keep it alive (contains lood vessels in this layer). The inner layer contains vitreous humor (the nutrient solution), the iris, the pupil to let more light in in the dark and less in the light. The lens does all additional focus which the cornea does not do, this is controlled by muscles which bend the lens in order to allow us to look at objects closer or farther away from us. The retina contains 3 layers, the photoreceptor layer detects the light (only light or no light), this signal then travels to the bipolar cell, this then goes to ganglion cell layer (only care about spots of light).
What is the critical period for humans for sight and what does this mean?
The critical period for human sight is roughly 3-9 months, if they cannot see by this point e.g due to congenital cataracts not having the lens replaced by this point, they will never be able to see as the pathways have not properly developed.
What are the key points on cones and rods?
Cones work during daytime, they see in color and in high resolution, rods worrk during the nighttime, have no color and are low resolution. The rods are located peripherally and there are insanely more rods than cones, which are located primarily in the centre of the eye (fovea).
What is the blind spot?
The blind spot is the area where all the retinal cell axons leave the eye (hence no photoreceptors here).
