Final

• perception: taking in information through our senses and processing it in order to determine what is out there in the world- perceiving the world 3 dimensionally 
• there is a large gap between the information coming into our senses and the kind of information that the brain actually wants to figure out about the world.
• A great deal of the brain is devoted to perception
• Perception can be divided into 2 stages- sensation
• Sensation- the conversion of physical properties of the world or body into a neural code by the peripheral nervous system- takes place in sensory neurons- spread throughout PNS
• Generally speaking, aphantasia in minor forms doesn’t really make a difference in IQ- same thing for minor Hyperphantasia
• Sensory neurons contain specialized nerve endings that are stimulated by specific kinds of physical properties such as pressure, heat, or light- leads to excitation of neuron
• Transduction- process of converting physical stimulation into a neural code- may be thought of as a kind of measurement of local conditions in the environment and the body. 
• After transduction, the signal is passed to CNS for perception
• Perception- the processing and interpretation of the sensory information into a form that is useful for a behavioral decision.
• we don't see with our eyes or hear with our ears. We do so with our brain, which receives the dense stream of millions of sensory signals from across the body and converts them into the world we see, hear, feel, taste, and smell.
• the features that ANNs learn often directly match those found in the biological brain. This is particularly true if the ANN is programmed to come up with a sparse code of the input
• Perception includes the five senses you are so familiar with: seeing/vision, hearing/audition, touch, smell/olfaction, and taste/gustation
• the five exteroception senses- seeing/vision, hearing/audition, touch, smell/olfaction, and taste/gustation
• Senses involve measuring (sensation) and interpreting (perception) properties of the external environment- exteroception 
• Each of the five exteroception senses uses different sensory mechanisms to measure the properties of the environment
• Vision is based on light entering the eye
• Hearing & audition is based on vibrations in the air entering the ear canal
• Touch is based on pressure, heat & vibrations on the skin
• Taste or gustation is based on substance bound chemical compounds in the mouth
• Olfaction is based on airborne chemicals in the nasal passage
• Its our brains that interpret senses into a coherent image that we can understand
• We have these different forms of exteroception because the various types of stimuli provide information that has distinct advantages and disadvantages- if theres no light, you can rely on other senses for example
• Vision has the highest spatial specificity
•  Introspection- multiple senses that measure properties of our own body- proprioception- nociception- equilibrioception- the sense of fullness- the sense of something in your throat
• proprioception, the sense of where in space our limbs are
• nociception, the sense of pain due to bodily damage
• equilibrioception, our sense of balance
• There are four broad classes of sensory receptors found throughout different parts of the body- chemoreceptors- mechanoreceptors- thermoreceptors- photoreceptors
• Chemoreceptors- have specialized nerve endings that respond to concentrations of chemicals in their local environment- nose, mouth, skin & internal organs- can measure buildup of chemicals related to tissue damage- support a kind of nociception
•  Mechanoreceptors are stimulated by physical force- skin, inner ear (vibrations), arteries (blood pressure).
• Thermoreceptors are stimulated by heat or cold and may be found in the skin as well as throughout several internal organs.
• photoreceptors have responses that are modified by light; increased light energy results in a lower levels of neurotransmitters being released- the inhibitory response to stimuli is specific to photoreceptors
• Images projected in the retina are upside down
• While perception is referred to under a single term, it is, of course, a collection of distinct sensory modalities, each with its own sensory mechanism and devoted brain structures.
•  Vision is arguably the most important sense in humans, with between one-third and one-half of the cortex involved in visual processing- best understood & most widely studied- principles are applicable to other modalities 
• All sensory modalities have the same basic process- transduction- transmission to brain- cortical processing to generate behaviours
• between one-third and one-half of the cortex involved in visual processing.
• The human eye is an organ whose purpose is to gather light, focus it, and turn it into a neural signal. As long as there is a light source, such as the sun, light is pervasive in our environment- fast & moves in a straight direction after bouncing off an object; makes it ideal for trying to infer spatial properties
• Light path into the eye- Cornea -> Iris’ pupil-> Lens-> retina