Psych Part 7 Flashcards
Mechanoreceptors
Pacinian Corpuscle - pressure sensor
Auditory hair cell - cochlea of inner ear
Vestibular hair cell - in semi-circular canals of the inner ear, detect relative position to gravity + acceleration
Chemoreceptors
Olfactory receptors
Gustatory receptors
Nociceptors
Simplest receptor, autonomic or somatic.
Note that nociceptors do not adapt, so we have to do something about pain.
Thermoreceptors
Detects changes in temperature. Autonomic and somatic examples.
Peripheral types: cold-sensitive; warm-sensitive; thermal nociceptors
Electromagnetic receptors
Only example in humans are photoreceptors
Encoding sensory stimuli
Modality
Location
Intensity
Duration (phasic, tonic, sustained)
Proprioception
Muscle Spindles (mechanoreceptor) - detect muscle stretch
Golgi tendon organs - detect stretch in tendons
Joint capsule receptors - detect pressure/tension/movement in joints
Gustation
Can only detect 5 flavours with 5 types of taste buds responding most strongly to a specific one.
Tate buds - composed of multiple epithelial cells with a taste pore at the centre with taste hairs that detect food chemicals.
Information from taste buds is moved from cranial nerves to temporal lobe.
Olfaction
Olfactory receptors located in the nasopharynx.
Chemicals dissolve into mucus of the nasal membrane. Neurons project to the olfactory bulb in the temporal lobe.
Note: there are no inherently noxious odours, this is entirely learned.
Auditory/Vestibular system composition
Outer Ear
Middle Ear
Oval Windom
Inner Ear
Outer Ear
Auricle
Pinna
Auditory canal
Middle Ear
Tympanic membrane
Ossicles: Malleus (hammer), Incus (anvel), Stapes (stirrup)
Inner Ear
Cochlea
Other components relevant to balance:
Semicircular canals
Utricle
Saccule
Eustachian Tube
Auditory Tube
Equalizes pressure on both sides of the tympanic membrane.
Connects to the back of the throat.
Mechanism of Hearing
Sound waves > ear drum > malleus receives vibration > incus > stapes vibrates oval window > Creates vibrations in the perilymph and endolymph in cochlea > Vibration in basilar membrane covered in hair cells that contact TECTROIAL MEMBRANE > hair cell displacement opens ion channels activating bipolar auditory afferents.
Organ of corti
Includes bipolar auditory afferents and the tectorial membrane.
Pitch and Intensity determination
Pitch - determined by region of basilar membrane vibration. Low frequencies are at the apex and higher frequencies are closer to the oval window.
Intensity - amplitude of vibration.
Vestibular Complex
Formed by 3 semi-circular canals:
Utricle
Saccule
Ampullae
All three are filled with endolymph and covered in hair cells that detect motion (rotational acceleration to be specific).
Vision structures and mechanism
Light > Cornea (refracts light) > Anterior chamber with aqueous humour > Iris with pupil opening (iris muscles dilate pupil) > posterior chamber with aqueous humour > Lens (tunes incident light and altered by ciliary muscles) > Vitreous chamber with vitreous humour .
Note that the cornea is continuous with the sclera and beneath the sclera is the choroid, which is the dark pigmented surface.
Special regions of the retina
Optical Disc - blind spot where ganglion cell axons form optic nerve.
Macular - in the centre is the fovea centralis, only cone cells here and high visual accuity.
Photoreceptors
Opsins respond to light.
Retinol when cis-bound; Na channels remain open (depolarized) when all trans form hyperpolarizes cell by closing Na+ channels.
Glutamate effect on bipolar cells
Inhibitory when released from photoreceptors, as only when photoreceptors hyperpolarize is an ON-bipolar cell activated.
Emmetropia
Normal Vision
Myopia
Nearsightedness - light is bent too much. Can be corrected with a concave lens.
Hyperopia
Farsightedness (light is bent too little and focuses behind the retina). Corrected with a convex lens.
Presbyopia
Inability to focus (accommodate) results from a lack of flexibility in the lens and usually occurs with aging.
Optic Chiasm
Where optic nerves unite and the NASAL innervating nerves cross over to the other hemisphere.
Consequence is that the left hemisphere process all input from the right visual field (and vice versa).
Optic Tract
In both hemispheres. Region between the optic chiasm and the lateral geniculate nucleus.
Pulvinar Nucleus
Superior Nucleus
I believe that this has some relevance to circadian rhythms
Rough divisions of cortical area between visual, touch, and auditory
Visual - 30%
Touch - 8%
Auditory - 3%
Consequently - we will favour, vision even if sight and smell contradict.
Feature detecting neurons in the visual cortex
Respond to specific features Ex. lines/edges/angles/movements
Note: Highly influenced by previous information as well.
Parallel Processing
Method of the brain to interpret visual scene. Do not use sequential processing.
Depth Perception
Appears to be innate (demonstrated in babies).
Achieved through binocular and monocular cues.
Binocular Cues
Retinal Disparity - compares distinct images formed by each retina. Objects further away look more similar, closer together look more distinct.
Convergence - How much the eyes have to turn in to see an object.
Monocular Cues
Relative Size - smaller is further away
Interposition - closer objects block further objects
Relative Clarity - hazy = more distant
Texture gradient - Coarse/distinct = near; fine/indistinct = far
Relative height - higher objects further away
Relative motion - faster moving objects when we move are closer
Linear perspective - parallel lines converge as more distant
Light and shadow - dimmer objects are further away and reflect less light.
Absolute Threshold
Maximum stimulus to activate sensory receptor 50% of the time.
This differs between individuals, age, organisms.
Difference Threshold
Maximum noticeable difference between two stimuli 50% of the time.
Webers Law
States that stimuli must differ by a constant proportion though proportion differs by stimuli.
Ex. weight = 2%; light 8%; frequency 0.3%
Signal Detection Theory
Tries to predict when we will detect a stimuli amidst other background stimuli.
4 possible outcomes:
Hit
Miss
False Alarm
Correct Rejection
Gestalt Theory
Comes from the german words “form” and “shape”.
Describes what we perceive but is not concerned with how.
Core principles that explain perceptual organization:
(1) Emergence - first identify outlines and then the constituent parts.
(2) Mulstistability - multistable perception, ambiguous images pop back and forth
Gestalt Grouping Laws
Law of proximity
Law of similarity
Law of continuity - perceive smooth continuous lines over disjointed ones.
Law of closure - perceive things as complete, and will autofill if necessary
Law of common fate - objects moving together or in synchrony are grouped
Law of connectedness - things that are connected are grouped together
Perceptual Processing
Bottom-up: sensors to higher cortical processing. Only occurs when we have limited experience with the stimulus.
Top-down: Experience/expectation is used to interpret the situation.
Broadbent filter Model of Selective Attention
The attended message as well as unattended messages pass through a SENSORY BUFFER.
A SELECTIVE FILTER for specific modalities and other physical properties creates a bottleneck that limits only the attended message to move to HIGHER PROCESSING.
It then moves into working memory.
Agnosia
The inability to detect a sense despite the correct functioning of underlying sensory system.
Often result of damage at the parietal occipital border.
Divided Attention
Describes ability to perform multiple tasks simultaneously.
Resource model of attention attempts to describe this: Basically limited resources with which to carry out tasks
Factors that impact our capacity to divide attention: task similarity; difficulty; practice
Information processing models
Central Assumption: information processing generally follows a process of attention > perception > storage in memory.
Broadbent Filter Model of Selective Attention
Resource model of attention
Alan Baddeley’s Model
Attenuation Model
Sub-types of for visual processing:
Spotlight effect and the binding problem
Attenuation Model
Information Processing model:
Response to Broadbent filter model and inability to explain the cocktail party effect.
Described the selective filter as only dampening unattended messages.
May also be explained by selective priming though.
Spotlight effect
In visual processing - selective attention for where we are actually focused.
Because we process with feature detection, spotlight effect can lead to binding problem is attention is divided (ie. attribute attributes of one object to another)
Alan Bradley’s Model
Better defines short term and working memory.
Central executive interacts with: (1) Phonological Loop (2) Episodic Buffer (3) Visual Sketchpad
All three then can transfer information to (and receive information from) long-term memory.
Piaget
Argued against seeing kids as little adults. Suggested that kids form schemas and test schemas around experience.
Experiences can either result in:
(1) assimilation of experience into existing schema
(2) accommodation by changing of a schema
Piaget 4 Cognitive developmental stages
(1) sensorimotor stage (<2 years) - develop object permanence, demonstrate stranger anxiety
(2) Pre-operational Stage (2 - 7) learn that symbols can represent things; egocentric; lack logical reasoning
(3) Concrete Operational Stage (7 - 11) think logically about concrete events, learn that there is conservation of quantity with change in shape.
(4) Formal operational stage (12 - Adult) abstract and moral reasoning
Problem Solving/Decision Making strategies
(1) Trail and Error
(2) Algorithms
(3) Heuristics
Common Barriers to Problem Solving
Confirmation Bias
Fixation - inability to see something from a fresh perspective
Functional Fixedness - functions of object considered fixed.
Types of heuristics
Availability Heuristics - decision based on examples most accessible to you
Representativeness Heuristic - generalization about people/events
Belief Bias - judge argument conclusions based on what you believe, not on the logic of the argument
Belief perseverance
Cling to our beliefs more and more despite contradictory evidence.
Relate to Belief Bias.
Consciousness
Awareness that we have of ourselves, our internal state, and the environment.
Sleep
Exact definition is a little unclear so typically defined through methods of measurement.
Polysomnography
Electroencephalogram (EEG)
Electromyogram (EMG, skeletal muscle movement)
Electrooculogram (EOG)
Relaxed State Versus Alert State
Relaxed: Alpha waves, low amplitude with high frequency (8-12 Hz)
Alert: Beta waves, with frequency 12.5 - 30 Hz
Non-REM sleep
4 Stages.
3/4 cycles of non-REM during the sleep.
Cycles of non-REM sleep are longest early in the sleep state.
Non-REM Stage 1
Theta waves.
Low-Moderate Intensity (3 - 7Hz)
EOG - indicates slow rolling eye movements
EMG - Moderate activity
Less responsive to stimulus and fleeting thoughts.
Non-REM Stage 2
Still theta but also shows K-complexes and sleep spindles.
EOG - no eye movement
EMG - moderate
Lower heart rate, respiration, temperature
K-complexes
0.5 seconds, large and slow.
Single wave amidst theta waves.
Sleep Spindles
12 - 14 Hz bursts with moderate intensity.
Last 0.5 - 1 second.
Stage 3/4
Slow wave sleep, delta waves. Deepest level of sleep.
High amplitude, low frequency (0.5 - 3 Hz).
EOG - nothing
EMG - moderate
Slow heart rate, digestion. Growth hormone released.
REM Sleep
Bursts of quick eye movement.
Waves are very similar to beta waves that occur during wakefullness, but more jagged ie. sawtooth. (16 - 25 Hz)
EMG - almost nothing
Also known as “paradoxical sleep” where people appear awake, but lack any skeletal muscle movement.
