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)