6 - Perception Flashcards
What is perception and psychology?
All experiences are a lie
Stimulation of parts of the brain dealing with perception
Understanding about the world must go through the process of perception
Convert outside physics into useful information with psychology
Studying how we get information about our environment
What is psychophysics?
Scientific study of the subjective experience of perception
Relationship between physical stimuli and psychology
What are our 5 main senses?
Sight (visual Hearing (auditory Smell (olfactory Taste (taste Touch (tactile/haptic)
What are our other senses?
Balance (equilibrioception; vestibular system, inner ear) Body awareness (proprioception, joints and muscles; arrangement of the body) Temperature (thermoception, skin/internal)
What is the difference between sensation and perception?
Sensation: Detection of physical energy by sense organs; transduction
Perception: Brain’s interpretation of sensory input; transmission and interpretation
Is this a useful distinction? Physical vs processing
Whole sequence of events as the process of perception/perceiving
What is the integration of sensory?
Senses can feed into each other
Brain can use information from 2 or more senses
Eating/drinking: Taste and smell
- Rubber hand experiment
Visual: See rubber hand but not real hand
Proprioception: Correctly orientated
Touch: Paintbrushes stroking both hands at the same
What is somatosensation?
Touch
Multiple layers of skin cells with receptors
Some known, some unknown
Pressure, temperature, “pain”
Sensors, action potential, brain
Being touched, hot cup of coffee, ice block
Pain: Sensors are being intensely activated, not separate “pain” sensors
What is the somatosensory cortex?
Touch -> Thalamus -> Somatosensory cortex
Thalamus: Small amount of processing
Different parts of the brain are activated
What is gustation?
Taste
Taste receptors in clumps, taste buds on the projections of the tongue, propilae
Soft (back) palette (roof of the mouth)
Chemicals from the food dissolve into saliva, taste buds respond
Chemical specific response
Five types of human taste receptors
Salt Sweet Sour Bitter Umami (savoury)
Mice have receptors that respond to fat and calcium
Ratio of activation indicates perception of taste
Processed foods increasing salt and sugar to cover bitterness of preservatives
Tongue maps of where receptors are located
Tongue maps is misinformation
What is olfaction?
Smell
Flavour: Simultaneous activation of taste and smell; sensory integration
Chemical receptors, olfactory epithelium, in the nasal cavity
Chemicals are floating around in the air, dissolves in mucus
Contact with receptors activate signals to brain
What is equilibrioception?
Balance
Vestibular system, the inner ear not associated with
Angular (rotational) acceleration in our head in all three directions
- Semicircular canals at right angles to each other, detecting
Partly full of a thick fluid
Receptor cells: hair cells projecting into semicircular canal, detecting a fluid
- Saccule, blob structures, detecting acceleration/deceleration
Partly full of a thick fluid
Receptor cells: hair cells projecting into semicircular canal, detecting a fluid
If you are still, the fluid is pulled down by gravity
If you begin accelerating/decelerating, due to inertia, the fluid moves in different directions
What is the body sense?
Proprioception
What our body is doing
Removal of the parts of the brain associated with touch and vision, can still know what our body feels
Can detect flexing or extending in the muscles and joints
Sensory integration
Leaning back too far, proprioception and equilibrioception
What is audition?
Hearing
Tuning fork vibration. Compression of air, high pressure. Expansion of air, low pressure.
Air pressure over space/time
Frequency: Times in a second pressure switches. Hertz
Pitch: High or low pressure
Amplitude (loudness): Change in pressure from neutral to high/low
What is the auditory localisation?
Two ears, different times to receive information
- Interaural time differences
- Interaural intensity differences
- Would be the same if anything directly in front/behind/above/below
Head is always moving a little bit, will force a front/back difference
Pinnae are different, bouncing around differently
How does conductiveness deafness occur?
Nothing wrong with the brain, some issues with the equipment in the ear
Transmission of sound wave cannot be properly transmitted to the basilar membrane
E.g. Age, trauma, excessive exposure
Can vibrate the skull or jaw for hearing
What is sensorineural deafness?
Damage to neural cells; hair cells or brain damage
E.g. Stroke, excessive exposure
Hearing aid: Take a pitch that you cannot hear, and changing it slightly
What are parts of the eye?
The cornea: Prevents foreign material entering and bodily material leaving
Iris: A group of muscles to change the size of the pupil (coloured)
Pupil: A hole
Lens: Transparent material that can focus
Sciera: Muscle that change shape of lens
Retina: Coating at the back of the eye with photoreceptrs (rods and cones) which have different colour pigments.
Fovea: Centre of the retina
Images from the world are upside down on the retina. The brain flips the image
What are visual pathways?
Actional potential to the brain.
Optic nerve, Lateral Geniculate Nucleus, Occupital lobe
Processing: V1, V2, V3, V4, etc.
Information in left visual field processed by the right hemisphere; right visual field processed by the left hemisphere
Left/right visual field: Everything to the left/right to the centre of what you are looking at
Optic chiasm, a curly x. Neurons crossing over into the other side of the brain
What is the laterisation of processing?
Tasks preferentially processed in one side of the brain compared to the other
Face processing in right hemispher, left visual field
Two half female/male face
What is the retina?
Network of neurons at the back of the eye
Light passing through neurons to access photoreceptors
What are rods and cones?
Electron microscope: Rods and cones
Convert light to neural signals, chemical pigments
Rods are more sensitive to light than cones
Cones are useful in high light conditions
What are the photoreceptor distributions?
Fovea has very high number of cones.
Rods in some kind of a parabola shape
Blind spot without neurons/rods. All neurons come together at a point of the optic nerve. No cones/rods there
What is the blindspot?
A4 page of blind spot
Brain fills in what should be there with what surrounds it
Colour fills and patterns
Blind spots are always on the nasal retina side
Each other eye can see the blind spot
What is sensitivity vs resolution?
Rods and cones passing their action potentials to ganglion cells (nerve cells)
Ganglion cells fires faster/slower
Ganglion cells have a larger number of rods, smaller number of cones
Many cones are sending action potentials to a single ganglion cell
The receptive field of the ganglion cell
Two TVs, same screen. ¼ million pixels, relatively large pixels and lower resolutions. 8 million pixels, small pixels and higher resolutions
Cones have a bigger field, but have a lower resolution, reverse for rods
