Lecture 5: Sensation And Perception Flashcards
What is Sensation? What are the 3 Basic principles?
Sensation is the detection of physical energy by sense organs (eyes or ears) which then send info to the brain. There are 3 basic principles in sensation, TRANSDUCTION, SENSE RECEPTOR, SENSORY ADAPTION.
What is Transduction?
The process of converting an external energy (light) into electrical activity within neurons
What are Sensory Receptors?
It’s a specialized cell responsible for converting external stimuli into neural activity for a specific system.
- Specialized cells in the back of the eye transduce light
- Specialized cells inside thew transfuse airborne odorant’s
What is Sensory Adaptation?
The process in which activation is greatest when a stimulus is first detected, practical and good for us cause otherwise we’d be tending to everything around us and that’s exhausting.
There are 3 types of Attention, what are they?
Inattentional blindness, Selective attention, Filter Theory of Attention
Inattentional Blindness
Failure to detect stimuli that are in plain sight when our attention is focused elsewhere
Selective Attention
Process of selecting one sensory channel and ignoring or minimizing others
Filter Theory of Attention
Mental filter that allows us to pay attention to important stimuli & ignore others, listen to messages from their left ear and ignore the right ear
Cocktail Party Effect
The ability to pick out an important message in a conversation that doesn’t involve us.
The Binding Problem
Our brains manage to combine, or “bind,” diverse pieces of information into a unified whole - different parts of our process the parts of the apple differently, so the regions aspect the pieces of info together, so as an apple.
What 4 Different Sense Systems Do We Have?
Visual system, Auditory system, Olfactory & Gustation system, Somatosensory systems.
Visual System - Light, What is it? What is the range of wavelengths?
The narrow range of wavelengths of light that we respond to, or can see.
- We can see on the same spectrum as X-Rays, UV rays, and Microwaves
- The wavelengths from 400nm purple to 700nm red
How Do We Perceive The Brightness of Objects?
So the part of the light is reflected by the object and part of it is absorbed by the object.
- White Objects reflects all the light that is shone on them
- Black Objects absorb all the light that Is shone on them, reflect none of it
What are Hues?
The colour of light…The primary colours are red, green, and blue
-> Addictive colour mixing - mixing different amount of primary colours, to get any colour.
-> Mixing equal amount of red, green, and blue light produces white light
How Does Light Enter The Eye? What controls the amount of light entered?
The light enters through the pupillary reflex - which is the closing of the pupils in response to light, to decrease the amount of light allowed into them.
- The Iris controls how much light enters the eye.
Basic Structure of Eye…Cornea, Retina, and Forea
Cornea, is a curved transparent layer that covers the iris and pupil. It bends light that comes into the eye to focus on the image in the back of the eye
Retina is located at the back of the eye and is responsible for converting light into neural activity (this is where transduction takes place)
- Contains 100million receptor cells for vision
Fovea, is the central part of the Retina and it’s responsible for acuity (sharp vision)
Good Example - you look at the laptop (Forea), and in the background you see students (Retina)
RECAP: What is the Cornea?
It’s a curved transparent layer that covers the iris and pupil
What is the Fovea?
It’s the central part of the Retina, and its responsible for the sharpness in your vision
What is Retina?
Located in the back of the eye, this is also where transduction takes place - converting light into neural activity
What are the 2 Receptor Cells?
Rods and Cones
What are Rods?
There are numerous rods, and they allow us to see basic forms and shapes.
What is Darkabaoation
The time it takes for rodes to regain their maximum sensitivity to light, usually happens when we enter a dimly lit room (movie theatre)
What are Cones?
They give us our colour vision
What is our Optic Nerve
It consists of a bundle of axons, that travels from the retina to the brain
What is the Blindspot?
The region of the retina containing no rods and totally devoid of sense receptors
What happens when optic nerve reaches optic chiasm?
Half of the axons cross in the optic chiasm, and half stay on the same side
What is it called when the optic nerve enters the brain?
Optic Tract
Where does the optic tract send mist of their info
The thalamus - primary visual cortex or v1
There are 2 major routes of vision….
- Visual information from the retina travels to the visual thalamus.
- Next, the visual thalamus sends inputs to the primary visual cortex (V1), then along two visual pathways to the secondary visual cortex (V2).
- One pathway leads to the parietal lobe, which processes visual form, position, and motion; AND one to the temporal lobe, which processes visual form and colour.
The remaining axons go to the midbrain - reflexes
What information does the parietal lobe process?
depth and motion - example; looking at a stove, fridge, sink and realizing your looking at a kitchen
What information does the temporal lobe process?
Visual form and colour
What are the 3 theories of colour theory?
Trichromatic Theory, Colour-blindness, Opponent process theory
What is Trichromatic Theory?
It’s a colour vision based on our sensitivity to the 3 primary colours. They are 3 kinds of cones, all sensitive to different wavelengths of light, red, green, and blue is very common.
What is Colourblindness?
It’s and absence of 1 or more types of cones. There are 3 types, Dichromates, Monochromats, and Trichromats.
Define Dichromats
Having 2 types of cones, but missing one type - example; red/green colour blindness, it’s more frequent
Define Monochromats
Only having 1 functioning cones, cannot see colours basically
Define Trichromats
Idea that colour vision is based on our sensitivity to three primary colours
- Possessing 3 kinds of cones.
What is Opponent Process Theory?
We perceive colours in terms of 3 pairs of opponent colours…..
1. Red or Green
2. Blue or Yellow
3. Black or White
Neurons that respond to red cannot respond to green at the same time
so this theory basically explains after images..
Auditory System - What is Audition?
It’s our sense of hearing
What is Sound?
It’s a vibration, a kind of mechanical energy traveling through a medium (ex. air). It’s the disturbance by vibration of molecules of air produces sound waves
What is Amplitude?
Height of sound wave, corresponds to loudness
What are the 3 parts of the ear?
Outer, Middle, and Inner
What is the outer ear?
The outer ears contains sense receptors for hearing transduce sound into neural activity. It funnels sound waves onto the eardrum
What does the outer ear contain?
It contains the Pinna, which is skin, cartilage flap, and it contains the ear canal
What is the middle ear?
The middle ear contains the ossicles which are considered to be the 3 finest bones of the body
What are ossicle’s responsible for?
The ossicles wave at the frequency of the sound wave, transmitting it from the eardrum to the inner ear.
What does the inner ear contain?
Contains the cochlea and hair cells, Transduction of auditory information occurs at the the choclea , more specifically in the hair cells
What is the role of the cochlea?
Cochlea (‘snail’) converts vibration into neural activity - where
transduction happens
Cochlea contains:
* The origin of corti: tissue containing hair cells
- Basilar membrane : membrane supporting the organ of corti & hair cells in the cochlea
What are hair cells
Hair cells (embedded within the organ of corti & basilar membrane) convert acoustic info into action potentials
What is auditory perception?
The Auditory nerve makes contact with the brainstem which sends auditory information to the auditory cortex
The Olfactory and Gustation systems - What is Olfaction?
Our sense of smell
What is Gustation?
Our sense of taste
How many odours can we detect ?
2,000 and 4,000
What are the 5 basic tastes that we cab detect?
- Sweet
- Salty
- Savoury
- Umami
- Bitter
Mini Description of Olfactory Receptors..
Olfactory Receptors transduce odorants
- Each olfactory neuron has a single type of olfactory receptor, which recognizes an odorant on the basis of its shape
- When olfactory receptors come in contact with odour molecules, action potentials in olfactory neurons are triggered
What are tastebuds?
Taste buds are sense receptors on the tongue that respond to the 5 basic tastes.
What happens after odours interact with sense receptors?
The information enters the brain: olfactory cortex, parts of the limbic system..
What happens when taste information interacts with tastebuds
It enters the brain: gustatory cortex, somatosensory, parts of the limbic system..
What is the Somatosensory System?
Our sense of touch, temperature, and pain
- We sense touch, temperature & pain through receptors in the skin
What happens once receptors receive information…?
It first enters the spinal cord…
- and then touch & pain activate local spinal reflexes before reaching the brain for perception (i.e., withdrawal reflex)
- lastly from the spinal cord, touch & pain information travel to the somatosensory cortex
What is Perception… Button up processing and Top down processing?
Button up processing -is when we construct a whole stimulus from its parts - starts with the beliefs and expectations we have, which we impose on the raw stimuli that we perceive (ex; edges of an object) and ends with us combining them into a meaningful concept (laptop)
Top down processing - starts with the beliefs
What is a Perpetual Set?
Set formed when expectations influence perceptions
- An example of top down processing, because our expectations are influencing how we perceive things
What is Visual Perception? (what does it consist of?)
It is organizing & interpreting visual information.
it consists of shape, depth, motion and constancy.
Define What Gestalt’s Principles are?
Gestalt = “whole”
It’s why we see the world as unified figures & “wholes” rather than jumbled lines & curves.
Gestalt psychologist
explain how we perceive objects as whole within their overall context.
What are Gestalt’s Principles?
- Continuity
- Closure
- Figure-ground
- Proximity
- Similarity
Figure-ground (What is Rubins Vase Illusion)
It’s known as an ambiguous figure, you can see a black vase in a white background or the two white faces depending what colour your looking at
Define Proximity?
Objects physically close to each other tend to be perceived as unified wholes
Define Similarity
All things being equal, we see similar objects as composing a whole, much more so than dissimilar objects
Define Continuity
We continue to perceive objects as wholes even if other objects block part of them
Define Closure
When some visual information is present, our brains tend to fill in what is. Missing like dotted lines.
Closure - What is Visual Perception/ Depth
Depth perception is the ability to judge distance and three-dimensional relations.
- The ability to see objects in in 3 dimensions , although images that enter the eye are two dimensional. It allows us to judge distance
*Babies have it as soon as they begin to crawl
What is Visual Perception/
Constancy?
The process by which we perceive stimuli consistently across varied conditions.
- Awareness of the fact that objects do not physically change despite changes in viewing conditions
The colour constancy -perceiving an object as having consistent colour even if the colour ur seeing is different due to lighting….There’s also shape/size constancy!
What is Prosopagnosia?
It’s known as a “face blindness” - can’t process facial features, even their own family member
Inability to recognize faces, Inability to process facial features holistically
What is Fusiform Gyrus?
FG is in the temporal lobe and plays a big role in facial recognition, once damaged it can produce prosopagnosia.
