The Mind (Sensation and Perception) - HOSA Behavioral Health

Sensation

The process of detecting internal/external stimuli

Perception

Process of interpreting sensory information

Stimulus

Anything that can stimulate a reaction from our sensory systems

Transduction

Translation of incoming sensory information into neural signals send to the brain

Sensory Adaptation

The tendency to pay less attention to an unchanging stimulus

Bottom-Up Processing

Brain’s use of incoming signals to construct perception → simple to complex

Top-Down Processing

Incoming information already has a structure imposed on it → prior experience guides processing

Psychophysics

Coined by Gustav Fechner, this is the scientific study of the relationship between physical stimuli and the reactions they produce in people

Absolute threshold

The smallest amount of stimulus that can be detected

Difference threshold

Smallest detectable difference between 2 stimuli

Signal Detection

2-part process where we analyze decision making in the presence of a faint stimulus

1. Actual intensity of stimulus,

2. Observer’s criteria for determining if stimulus occured

Cornea

Clear surface in front of the eye that begins bending light into the retina

Iris

Brightly-coloured muscle surrounding the pupil, adjusts opening of pupil in response to light intensity

Lens

Clear structure behind pupil that bends light towards the retina

Retina

Layers of visual processing cells (rods and cones) in the back of the eye that transduce information

Fovea

Area of retina specialized for detailed vision → central vision

Rod

Photoreceptor specialized for dim light → peripheral vision. Provide no information about colour and views dim light better than central vision. About 90 million /eye

Cone

Photoreceptor in retina that processes colour and fine detail. ABout 4-5 million /eye

Blind Spot

Optic nerve exit without rods or cones

Optic Nerve

Nerve exiting the retina of the eye. Cross at the optic chiasm, where inners cross over and outers stay on the same side

Trichromatic Theory

Theory of colour vision stating there are cones from different wavelengths of light → blue, red, and green. This theory cannot explain coloured afterimages

Opponent Process Theory

Theory suggesting we have a red/green colour channel and a blue/yellow one. Activation of one colour in each pair inhibits the other. Does not account for the fact that most people have 3 cone types (those who have 2 are colour blind, and those with 1/none see in black and white)

Organization Principle - Gestalt Processing

Input is analyzed by splitting into foreground and background

Proximity Principle - Gestalt Processing

Objects that are close together tend to be grouped together

Continuity Principle - Gestalt Processing

Assumption that point which form smooth lines are connected together

Closure Principle - Gestalt Processing

We ‘fill in the blanks’ when an image contains gaps or lines

Simplicity Principle - Gestalt Processing

We will always use the simplest solution to a processing problem

Monocular Cue

Depth cue requiring the use of only one eye

Occlusion

The blocking of images of distant objects by closer objects

Binocular Cue

Depth cue requiring both eyes

Retinal Disparity

Difference between images projected onto each eye

Outer Ear

Pinna, Auditory Canal, and Tympanic Membrance (ear drum)

Pinna

Collects and focuses sound, helps us locate sounds as above/below head

Middle Ear

Oval window and tiny bones

Oval Window

Boundary between outer and inner ear

Tiny Bones (ears)

Transfers sound energy from the air in the outer/middle ear to fluid in the inner ear

Inner Ear

Cochlea, cochlear duct, basilar membrane, and organ of corti

Cochlea

Structure in inner ear containing auditory receptors → 3 chambers divided by 2 membranes:

1. Vestibular canal (sound waves produced in fluid here)

2. Tympanic canal (travels to apex and back through here)

Cochlear Duct

Lies between vestibular and tympanic canals, seperated by basilar membrane

Basilar Membrane

High frequency tones produce maximum movement of the base, low frequency tones produce minimum movement

Organ of Corti

Lies on basilar membrane and contains auditory receptors

Path sounds take in the brain to be interpreted (5 steps)

1. Medulla

2. Midbrain (reflexive responses to sounds)

3. Thalamus

4. Primary Auditory Complex (analyzes sound)

5. Secondary Auditory Complex (responds to complex stimuli)

With maximum sensitivity, we can hear sounds between…

80-10,000 Hz

Vestibular System

System in inner ear that provides information about body position and movement

Vestibular Information travelling through the brain: (4 steps)

1. Travels up to medulla

2. Thalamus

3. Primary Somatosensory Cortex (parietal lobe)

4. Primary Motor Cortex (frontal lobe)

The two parts of the body that are most sensitive to sensory stimuli are:

Hands and mouth

The path pain takes through our nerves is… (3 steps)

1. Free nerve endings that respond to pain are triggered by tissue damage

2. Pain fibers form synapses with cells in the spinal cord, sending messages to the thalamus

3. Thalamus → Anterior Cingulate Cortex

Olfactory Nerve

Nerves carrying olfactory (smell) information from olfactory receptors to olfactory bulbs

Olfactory Bulbs

One of two structures below the frontal lobe that receive input from olfactory receptors

Olfactory pathways in the brain are… (3 steps)

1. Fibers from olfactory bulb

2. Olfactory cortex

3. Amygdala

Papillae

Bumps on the tongue containing taste buds

Taste Buds

Structures within papillae containing taste receptors. Have a limited lifetime and are replaced. As we grow, we have less of them

Perfect Pitch

One can name the exact musical tone that is heard - can be trained