Exam Flashcards
Rene Descartes
(Substance) Dualism
Mind and body are different kinds of substances
The body is divisible
The mind is not divisible
The mind is completely different from the body
Gilbert Ryle
The mind is a dogma of the ghost in the machine
A category mistake
Dualism
Rene Descartes
Gilbert Ryle
The belief that the mind and the body are different kinds of substances - mental substance + physical substance - they exist independently
The mind + the body are separate entities
Materialism
Monism
Everything is material/physical
Reality is a physical matter
Our mind is a figment of out imagination
Mentalism
Monism
The physical world cannot exist without the awareness of the mind
Only the mind really exists - the physical world could not exist unless some mind were aware of it
Identity position
Monism
Every mental position is a brain activity - thoughts are the same as brain activities
The mind is what the brain does - the mind is a brain activity - mental activity is what is happening to the brain
Monism
The universe consists of only one substance
3 forms of monism
Materialism
Mentalism
Identity position
Consciousness
The person’s subjective experience of the world and mind
Experiences that can be overtly reported
Libet
RP = readiness potential - electrical activity before a movement
Perform simple movements
Report when they made the decision to move
Recorded RP
Brain activity started 350ms before conscious decision to move
Dehaene
Masked vs Unmasked pairing
Target stimulus primed by a preceding stimulus
Blank screen pre+proceeding = can recognise word
Patterned screen pre+proceeding = cannot recognise word
Rett syndrome
Young girls <2
Loss of speech, motor control + functional hand use
Seizures, orthopaedic + sever digestion problems
Mutations in MeCP2 protein present in neurones + astrocytes
Re-expression in mice dramatically reverse symptoms
Astrocytes
Surrounding neurones + holding in place
Supply nutrients + oxygen
Modulate neurotransmission (mop up NTs)
Oligodendrocytes
Myelin sheath
Electrical conductance
Radial glial
During development - provide scaffolding for neurones to migrate to their final destinations
Microglia
Remove dead neuronal tissue
Act as immune defence
Multiple Sclerosis
Fatigue, visual problems, difficulty walking
Diagnosis: 20-40
More common in women
Demyelination of neurones
Phenology
Correlation of brain anatomy with behaviour/personality
Broca’s area
Speech
Broc is chatting
Corpus colostomy
Lesions of corpus callosum
Interrupt communication between hemispheres
Phineas Gage
Frontal lobe damage
Personality change
Transcranial magnetic stimulation (TMS)
Stimulate neurones via externally applied time-varying electromagnetic fields generated by a coil over the head
Somatosensory
Sensation that occur anywhere in the body - touch, pressure, temperature
Not localised to a sense organ such as sight, taste, smell etc.
Blindness
Visual cortex recruited in somatosensory processing
VC activated by somatosensory input in blind patients
Blind subjects - stimulation impaired tactile reading
Grandmother cell
Complex but specific
Responds to only one stimulus ie. vision, hearing etc.
Event-related potential (ERP)
Measured brain response as a result of a specific sensory, cognitive or motor event
Measured via EEG
EEG activity is time-locked to a specific external event
Excellent temporal resolution
Poor spatial resolution - sum of signals
Magnetoencephalography (MEG)
Recording of magnetic fields produced by electrical currents in the brain
Nissl stains
Cell bodies (RER)
CT Scan
Inject dye into the blood
X-rays from different angles
Absorption depends on density
Metal > bone > tissue > fat > water > air
Function only
MRI Scan
Strong magnetic field applied
Energy released by molecules in tissue is measured
Function only
fMRI
Brain activity + structure
Oxy-haem vs deoxy-haem blood
PET Scan
Measures local blood flow to a region
Radioactive tracer (FDG - glucose) injected - emits positrons
Slower temporal resolution
Syndactyly
Fingers/toes connected by skin tissue
Before surgery: overlap in brain region as they are not separate
After surgery: more separate brain regions that are responsible for each digit
Phantom pain
Amputated patients - can feel pain in absent limb
80/90%
Neurones from other body areas invade the area that normally receives input from the missing limb
Therapies that relieve:
Functional prosthesis - artificial limb
Mirror box effect - mirror placed between legs of someone who has lost a limb.
Pain/irritation alleviated from the phantom limb via the other limb due to the brain perceiving this to be the other ‘leg’
Outer ear
PINNA
Pinna
Captures the sound and amplifies it by funnelling it into the smaller auditory canal
Middle ear
Eardrum collects the vibrations
Detect sound when the eardrum vibrates as little as the diameter of the hydrogen atom
Ossicles
Eardrum transmits vibrations to 3 ossicles:
Hammer, anvil, stirrup
Lever action of ossicles transfers the vibration to the cochlea
Cochlea
Divided into 3 fluid-filled canals
Vestibular, tympanic, cochlear canal
Stirrup ossicle transmits vibrations to cochlea + the organ of Corti
Organ of Corti
Sound-analysing structure
4 rows of hair cells embedded in the basilar membrane
Vibration bends the hair cells, opening K+/Ca2+ channels
Depolarises cells - sets off signals in neurones
Hair cells synaptically excite the cells of the auditory nerve (8th cranial nerve)
Auditory nerve
Cranial nerve 8
Auditory pathway
Brain stem = ipsilateral cochlear nuclei Brain stem = superior olivary nucleus Midbrain = inferior colliculus Thalamus Auditory cortex
Frequency
Pitch
Sound intensity/energy
Loudness
Neurone firing rate - fire more Hz when sound intensity increases
Tonotopic organisation
The organisation by which sound is encoded anatomically on the basilar membrane (Organ of Corti, cochlear)
<200Hz
Temporal Code
Intensity encoded via the number of individual firing neurones
200-2000Hz
Place Code
Tonotopic organisation
Basilar membrane
Relative pitch
Distance of a musical note from a given reference point
Absolute (Perfect) Pitch
Ability to name/produce a musical note without an external reference
Congenital Amusia
Tone deafness ~4% population
Present from birth/develop from brain damage
Inability to recognise familiar melodies, read musical notation, detect wrong/out of tune notes
Cannot sing, write musical notation or play an instrument
Conductive hearing loss
Damage to outer/middle ear
Problem conducting sound waves
Sensineural hearing loss
Damage to cochlea/hair cells in the inner ear
Disease or exposure to loud noises
Corrected by cochlear implants
Tinnitus
Cause
The perception of sound within the human ear in the absence of corresponding external sound
Inner ear damage by:
aging, medication, noise-induced hearing loss
Persisting sound due to enlarged sector in the auditory cortex - neurones are responding in a coordinated way in the absence of sound
2 types of tinnitus
- Ringing dependent on abnormal patterns of activity that the damaged inner ear is feeding to the brain
- Plastic brain changes to the extent that it can sustain itself without ear inputs to generate the continuous noises
Light waves:
Length
Amplitude
Purity
Hue/colour
Brightness (intensity)
Saturation/richness of colour
The human eye cells
Rods/cones
Rods/cones converge onto bipolar cells
3 cones
Bipolar cells –> retinal ganglion cells (RGC, optic nerve) –> photoreceptor cells
Fovea
Periphery
Central portion of retina
High acuity
Single receptor, single bipolar cell, single ganglion cell
Periphery - more convergence of receptors onto common bipolar/ganglion cells - smaller acuity
Better sensitivity to dim light
Periphery
Receptive field (vision)
Region of sensory surface that causes a chance in the firing rate of a cell when stimulated
Optic nerve = single ganglion cell
Ganglia cell integrates info from adjacent rods/cones
Each ganglion cell responds to a specific pattern of light falling within a certain patch
Ganglion cells
At least a dozen types
Tell the brain different information ie. contrast, direction, speed etc.
Output form the basic of visual perception
Uniform distribution of these cell types on the retina - retinal tiling
Rods/cones
Cones = abundant in the fovea
Responds to bright light
Colour vision
Rods = abundant in the periphery
Responds to dim light
Cones types
Blue/green/red
Short/medium/long wavelengths
Colour perceived based on relative response of all 3
White = all 3 are equally active
Blue cones are rarer but most evenly distributed
Colour constancy
The ability to recognise colours despite changes in lighting - human brain factors out changes in lighting
Early visual neurones respond to the actual wavelength
Neurones later one in the processing stream respond to perceived colour
The dress debate
Blue/black = correct for warm lighting
White/gold = correct for cool lighting
Eye to the brain
Minority:
Ganglion –> Superior colliculus
Majority:
Ganglion –> lateral geniculate nucleus (LGN, thalamus) –> primary visual cortex
Simple receptive cells
Visual cortex
Bars
Angles of lines
Hubel + Weisel
Complex receptive fields
Visual cortex
Moving light patterns
Medium sized receptive field
Hubel + Weisel
Hypercomplex cells
Large receptive field
Bar shaped
Strong inhibition on one end
Hubel + Wiesel
V1 Function + Organisation
Primary visual cortex
Simple, complex + hypercomplex cells
Edges!!!
Cells of similar properties grouped together in COLUMNS - striated cortex
Columns follow topographic organisation
Adjacent columns process adjacent portion of the visual field
After primary visual cortex (V1)
V1 has connections to secondary visual cortex (V2)
V2 has connections to tertiary visual cortex (V3)
V2+v3 = contain complex + hypercomplex cells
Also contains cells that respond to even more complex patterns such as:
circles, lines that meet at right angles etc.
V2/3 - information passed onto several regions across the occipital lobe
Visual properties such as colour, shape, motion, location etc. processed different brain regions
V4
Colour processing
Cells in V4 respond to different colours
Cerebral achromatopsia
Damage to V4 - colour processing
Intact colour naming from memory - impaired colour naming for objects in visual field
Describe surroundings as being darkly coloured
Have intact shape + motion processing
Intact achromatic distinction (grey levels)
V5
Motion processing
Cerebral akinetopsia
Loss of movement vision
Unable to perceive the movement in a cup, so cannot pour drink
Difficulties following dialogue
Vision - WHAT
Temporal cortex
Ventral stream
SHAPE
Identifying/recognising objects
Damage = agnosia
Vision - HOW/WHERE
Parietal cortex
Dorsal stream
LOCATION/MOTION
Guides movements ie. Picking up cup
Damage does not impair identification - impairs understanding of where things are - issues grabbing items
Damage to superior parietal cortex = optic ataxia - inability to pick objects up correctly
Visual agnosia
Damage to ventral stream
Optic ataxia
Superior parietal lobe damage
Inability to guide reaching movements
Ie. Pick up glass
Balint’s syndrome
Inability to see more than one object at once
Binding problem
Visual system binds different visual properties/features
ie. colour, shape, motion, location in different brain regions
Accurate perception - putting right features together
Visual features initially processed separately - gets forwarded onto a master map
Common visual person cues
Facial expression/morphology
Hair style
Body shape + posture
Actions
Common social judgements
Social category - age, race, gender Emotional state Attractiveness/health Social attention Personality
How to identify the core face perception network
Quadflieg
Face perception
Faces = highly homogenous
Subtle differences
Assess HOLISTICALLY - combine various facial features of each face into a unique whole
Habitually fuse upper/lower part of face
Harder to report identity of top face when mixed w/ different lower face
Holistic face processing breaks down when INVERTED = harder to recognise
Fusiform face area
Holistic processing of faces
Inversion effect
Occipital face area
Feature-Based processing
Inversion effect
Posterior superior temporal sulcus
Processing dynamic info
ie. Movement
Prosopagnosia
Face blindness
Have to use alternative cues to identify people
ie. Clothing
Person perception network
Perceive invisible person qualities to predict their actions
Requires a cognitive leap - may not necessarily be accurate
If network’s normal processing is inaccurate, person inference problems can arise
Understanding of other peoples intentions/inferring mental states etc.
ie. Impaired false belief reasoning - people will not understand the intentions of others
The Classic View
Interaction between the person perception network _ the extended network
Sequential processing of information
Core networks create representation based on visual input
Representation then used by extended network to exploit the socially relevant info
The Alternative View
Interaction between the person perception network _ the extended network
Simultaneous exchange between both networks
Core network creates representation based on visual input + person’s experience/expectations/goals
Extended network generates predictions that support/guide processing in core network
Emotion
James-Lange
A stimulus causes a specific physiological state which produces the action
Predicted those with weak autonomic abilities will experience less fear
Paralysed people do report feeling fearful BUT paralysis does not affect the autonomic nervous system
Botox causes paralysis = Ps take longer to read unhappy sentences + a reduction in emotional responses
Damage to somatosensory cortex - normal autonomic physiological responses to emotional music, but little subjective experiences
Pure autonomic failure - no output from ANS (no regulate of HR etc.) - can still identify emotions in others, but their own emotions less sensitively
Enhancing responses to emotion: comic strip
Held a pen in mouth to activate smile muscles - found the comic strip funnier
Mobius syndrome
Entire face paralysed due to cranial nerve damage
Struggle to show emotion
No problem processing/experiencing emotions
Do you need to be able to produce emotion to recognise it in others?
Mobius syndrome
No impairment in recognising basic types of facial expressions
Mild impairment in facial recognition
Emotion
Cannon-Bard theory
The stimulus leads directly to the experience of fear
Emotional stimulus triggers both autonomic response + emotional experience in the brain
ANS responds too slowly to account for rapid onset of emotional experience
People have problems recognising ANS symptoms (ie. HR) so how can it lead to a change in the experience of an emotion?
Non-emotional stimuli have the same ANS activity that emotion evokes (ie. temp. rise), why don’t we feel afraid when we have fever?
Not enough patterns of ANS activity to represent the array if unique emotional experiences we have
Emotion
Schater + Singer
General physiological state experienced, and then the interpretation of the stimulus occurs before the experience of fear
James-Lange
Canon-Bard
Schater + Singer
Specific physiological reaction then experience
Stimulus leads to experience
General physiological reaction is interpreted to get the experience
Areas associated with emotion
Limbic area
Amygdala
No specific areas for specific emotions
Insular cortex/basal ganglia = disgust
Insular related to gustation - responds to pleasant/unpleasant tastes
Damage to both areas = impairment in producing disgust and in recognising in others
Insular cortex + basal ganglia
Disgust
Insular - gustation
Damage to areas - cannot produce disgust, or recognise in others
Testosterone
Associated with aggression + social dominance
High levels associate w/ violent crimes
Increased testosterone = delays the ability to detect the face of threat in others
Ps given testosterone
Identified aggression at a later stage
Serotonin
Low levels - higher aggression
Higher levels in monkeys - more likely to attack the bigger monkeys
Predicts convictions of crime
Strongly linked to depression
TRYPTOPHAN - synthesised from amino acids - higher levels impairs the ability to make serotonin
High amino acid diet - correlated w/ aggression/suicidal tendencies
High amino acid diets correlated w/ depression, impulsivity + aggression
Serotonin is not specific to aggression - may just be involved in behavioural regulation
Fear + anxiety
Amygdala
Input from pain, vision + hearing centres
Projects to:
Hypothalamus - controls ANS responses
Prefrontal - modulates behaviour
Pons - startle response
Pons - links signals to startle response (emotion)
Amygdala = fearful (+happy) faces
Activation pattern may be due to detecting ambiguity in face (not necassarily processing of -ve info)
Activated:
Angry face>scared face because angry=more ambiguous
Toxoplasma Gondii
Cat is infected + poos
Rodents eat poo
Destroys amygdala
Urbache-Wiethe disease
Amygdala shuts down Doesn't feel fear Excited when watching horrors Feels every emotion except fear Cannot draw or recognise a face of fear
Consolidation of emotional events
Stressful or emotionally charged experiences are accompanied by secretion of adrenaline/cortisol
Activates amygdala/hippocampus
Enhances consolidation and storage of recent experiences
Working memory
Decline in memory in older linked to reduced prefrontal activity
Older people w/ intact memory show greater PFC activation than young people = working harder to maintain performance levels/compensate
May need to recruit bilateral processing in order to perform as well
Hippocampus
Amnesia
Patient HM
Patient HM - bilateral removal of hippocampus.temporal lobe for epilepsy
Anterograde+retrograde amnesia
Intact working memory + semantic memory
Poor episodic emory
Explicit + declarative memory is impaired
Implicit memory intact - includes procedural memory
Spatial memory
Hippocampus
Respond at different locations in space or when the animal is facing different directions
Different electrodes fire when rats run around in a maze - different neurones active @ different locations
Prefrontal cortex
Working memory
Reward leanring
Basal ganglia
Implicit learning
Semantic
Procedural
LTM
Temporal cortex
Semantic
Conceptual knowledge
Hippocampus
LTM Declarative Episodic Spatial Explicit
