perception 4

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sensation

sensation

conversion of physical properties of the world or body into a neural code by the peripheral nervous system

the three interoceptive sensations from inside our body are the ____

nociception

proprioception

sense of where our limbs are in space

Nociception

sense of pain due to body damage

equilibrioception

sense of balance

perception

the processing and interpretation of the sensory information into a form that is useful for a behavioural decision

transduction

the process of converting outside stimuli into neural code

exteroception

sensing and processing information from the five senses

• vision

• audition

• touch

• taste

• smell

the visual sensory system

composed of the early visual processing and the late visual processing

photoreceptors

• convert light energy to neural code

• there are rods and cones

rods

• low light levels for night vision

• no colour

• low resolution

cones

• high resolution

• good for seeing sharp details in colour

blindspot

area where the optic nerve leaves the eye

no photoreceptors

early visual processing steps

• light waves enter the eye and have to pass through the cornea

• the cornea bends the light so the image is inverted and passed through the pupil in the iris

• from the pupil

the light goes to the retina

• the electric signal is sent to the bipolar cells and then the ganglion cells

• the signal leaves through the optic nerve to get to the brain

retina

• structure in the back of the eye

• contains multiple neurons including photoreceptors

fovea

• part of the retina where cones are highly concentrated

• makes the centre of your visual field most detailed

where are the rods located

periphery of the retina

optic nerve

bundle of axons that transmit visual information from the retina to the brain

thalamus

• important for sensory relay

• subcortical region of the brain that serves as a station between sensory inputs and the cortex

primary visual cortex

the first region of the cortex to receive visual input

input from the eyes to brain is __

compressed

blindsight

• can occur due to head injury or stroke

• no conscious awareness of visual objects in the damaged visual field

• able to indirectly answer qsts about objects in damaged visual field

• suggests indirect perception

dorsal "where" pathway

• spatial information

• depth perception

• estimate movement and direction of objects

• takes information to the posterior parietal lobe

akinetopsia

• damage to the dorsal pathway

• visual motion blindness

• cannot see motion

instead sees a series of stationary objects

optic ataxia

• damage to the dorsal pathway

• inability to reach for objects but can name objects

visual agnosia

• damage to the ventral pathway

• difficulty recognizing everyday objects

• difficulties can be selective to visual categories

prosopagnosia

• fusiform face area damage

• inability to recognize faces but can recognize objects

apperceptive visual agnosia

• failure of recognizing objects b/c of problem w/ perceiving elements of the object as a whole

• problems with perception and discrimination of objects

associative visual agnosia

• inability to associate visual input with meaning

• can't access information from memory

constructivist theory of perception

• top down theory of perception

• perception influenced by knowledge and context

• unconscious guesses to interpret nd predict sensory data

gestalt organizational principles

• whole is greater than the sum of its parts

• fundamental organizational principles to deal with ambiguity in our environment

principle of experience

• we see what we are familiar with the most

• principle of proximity

features close to another will be perceived as belonging together

principle of closed forms

• see shapes in terms of closed forms

principle of good contour

perceive objects as continuous where it is expected they continue

principle of similarity

organizing objects of a scene based on similarity

direct models

• passive bottom up approach to perception

• cues in the environment that guide how our sensory info. is processed and leads to perception

phonemic restoration effect

when the brain fills out details of missing sounds from a speech signal based on sensory input

Cortical Homunculus

spatially organized map of the human body

travel path of neural information for visual info. from right eye to left lobe of PVC

1. right retina

2. right optic nerve

3. optic chiasm

4. left optic tract

5. left thalamus

6. left lobe of the pvc

binocular disparity

features of an image fall on the retina of the two eyes