Week 4-6 Flashcards
What is the relationship between brain mass and intelligence?
Larger brain mass means a wider range of intelligent behaviour.
However absolute size does not indicate intelligence - rather the proportion of brain to body mass is more important.
What is the Encephalisation quotient?
Why is this useful?
The size of the brain relevant to body mass.
Indicates high species IQ.
Where is the cerebral cortex?
How is this different between humans and other animals?
The outer most layer of the brain.
Made up mostly of grey matter.
Has folds - small mammals have smooth cerebral cortices.
What brain functions is the cerebral cortex involved in?
Attention Perception Awareness Thought Memory Language Consciousness
What are some ways we can understand the relationship between the brain and behaviour?
Investigate what happens when the brain is damaged or impaired - can be caused by trauma, disease, accidents, or experiments
Why are accidents and disease a limited approach to understanding the function of brain areas?
The show what damage to certain parts of the brain will do to function, but can’t be controlled or replicated.
What are examples of invasive techniques?
Ablation
Surgical modification
Psychosurgery
Deep brain stimulation (DBS) - electrodes inserted into the brain to stimulate different areas
What are examples of non-invasive techniques?
EEG - electroencephallography
TMS - Transcranial Magnetic Stimulation
Transcranial Direct Current Stimulation
When would it be appropriate to use electroencephalography (EEG)?
EEG records brain activity using electrodes placed in various locations on the scalp.
Useful for: Seizure disorders Sleep disorders Changes in behaviour After severe head injuries
Pro: Can see brain responses very quickly
Con: Offers poor spatial resolution
What is MRI?
What is it useful for?
What are the pros / cons?
Magnetic resonance imaging
Powerful magnetic fields to measure different kinds of tissue in the body - white matter, grey matter, cerebral / spinal fluid
Useful for: Tumour Soft tissue injuries like ligaments Joint injuries Spinal injuries Internal organs
Pro: Bold contrast - get definition!
Con: Poor temporal resolution - blood takes time to reach brain regions
What is PET?
Positron emission tomography
Radioactive materials injected intravenously that bind with molecules in the body such as water.
Can scan before and after treatments to see which brain regions show changes.
Con: Poor temporal resolution
What is TMS?
Transcranial magnetic stimulation
Attach electrodes to the scalp to induce electric currents inside the brain
Pro: Relatively painless
What is DBS?
What is it used for?
What are the pros / cons?
Direct brain stimulation
Electrodes inserted into the brain.
Relatively new technique.
Used for: Parkinson's Essential trmor Depression OCD
Cons: Invasive brain surgery! Used only in new cases
What are the parts of the Hindbrain?
Medulla oblongata
Pons
Cerebellum
What is the medulla oblongata?
Passes messages from spinal cord and brain.
Located at the base of brain where it connects to spinal cord.
Responsible for:
Cardiovascular system
Respiratory system (coughing, sneezing)
What is the pons?
Relays signals from the forebrain to the cerebellum.
Sends information from the face, eyes, and ears to the brain.
Largest part of the brainstem.
Located above the medulla and below the midbrain.
Responsible for: Sleep Respiration Swallowing Bladder control Hearing Equilibrium Taste Eye movement Facial expressions Facial sensations Posture
What is the cerebellum?
Means ‘little brain’
Works unconsciously on aspects of motor control, gait and posture
Located below the cortex and behind the brainstem
Responsible for:
Motor control
Balance
Movement
What are the three parts of the midbrain?
Colliculi
Tegmentum
Cerebral peduncles
Responsible for visual and auditory input and processing
What is the superior colliculus?
Transforms sensory input into movement output.
Responsible for:
Receiving input from the eyes
Orientation of eyes and head
What is the inferior colliculus?
Main auditory centre of the body
What is the cerebral peduncles?
Connect the midbrain to the brainstem
Which part of the brain is associated with “higher order” or more “human” features?
Forebrain
Evolutionarily newer part of the brain which has evolved to help humans solve problems within our environment
What are the parts of the forebrain?
Cerebrum Thalamus Hypothalamus Pineal gland Limbic system
What is the cerebrum?
Largest part of the brain
Responsible for: Initiation of movement Coordination of movement Touch Temperature Vision Hearing Judgment Reasoning Problem solving Emotions Learning Reading Writing
What is the thalamus?
Relays motor and sensory signals to the cerebral cortex.
Responsible for:
Sensory inputs (vision, hearing, touch, taste)
Regulation of consciousness and alertness
Memory
Emotion
Arousal
What is the hypothalamus?
Links the nervous system to the endocrine system via the pituitary gland
Responsible for: Eating Drinking Stress regulation Temperature regulation Memorizing The Four Fs (fighting, fleeing, feeding, "mating")
What is the substantia nigra?
Damage is implicated in movement disorders such as Parkinson’s
Responsible for: Motor control Motor learning Executive functions Emotions
What is the hippocampus?
Responsible for:
Consolidating short term memories into long term memory store
Spatial recognition and memory (map reading, navigation)
Damage affects memory acquisition - still able to form physical or motor skill acquisition
What are the amygdalae?
How do we know what they are responsible for?
Responsible for:
Fight or flight response
Memory
Fear and aggression responses in animals
Case study with damage to amygdalae claimed that she was afraid of certain things but showed no fear responses to them
What are the sulci and gyri?
Sulci - valleys of the wrinkles in the brain
Gyri - Bulgy parts of wrinkles in the brain
The brain is split into hemispheres connected by what structure?
Why might you sever this?
What happens when you do?
Corpus collosum
Allows info from one hemisphere to be shared with the other
Split brain surgery may be used for severe epilepsy that travels from one side of the brain to the other
People recover well but may suffer side effects such as spatial neglect syndrome. Patients may still respond subconsciously to the object on the bad side.
What are the four lobes of the cortex?
Frontal
Parietal
Temporal
Occipital
Where is the primary motor cortex?
Centre top of the brain
What order is your motor cortex organised in?
Upper part controls feet, legs, groin and torso
Lower part controls hands, arm, face, and tongue muscles
Which body parts have larger representation in the motor cortex?
Why?
Hands and face
Humans tend to use these a lot more for fine motor movements than legs or torso
What techniques might you use to understand the motor cortex?
Brain injury
Neuroimagery
Non-invasive stimulation such as TMS - targeting the upper reaches will get twitches in the feet, etc.
The dorsal lateral pre-frontal cortex (DLPFC) is involved in what types of cognitive functions?
Executive functions: Cognitive processes Problem solving Holding items in working memory Deep thoughts Engaging in rules Future planning Inhibiting inappropriate responses E.g. Planning a dinner party, sitting an exam
Where is the somatosensory cortex?
Top middle/back
What does the somatosensory cortex do?
How do we know?
Perception of touch (pressure, pain, temperature)
Spatial navigation through environment - brain makes a map of our bodies in relation to our environment - avoids interactions with objects like walls and furniture
Penfield and Boldrey (1937)
Operations on patients with serious issues - electrical stimulation of parts of the cortex - patients would report different sensations in different parts of their bodies
How is the somatosensory cortex comparable to the motor cortex?
Also organised in a hierarchical manner:
Legs, torso, and feet represented higher
Hands, face, and neck represented lower down
Larger area associated with hands and face
What does the parietal lobe do?
Processing of sensory info - touch and limb position
Spatial navigation and awareness
Where does visual information get processed in the brain?
Through the thalamus to the occipital lobe / primary visual cortex
What is cortical blindness?
What makes it different to other forms of blindness?
Patient will be unable to see anything at all
Damage to the occipital lobe rather than anything to do with the eyes
Where does auditory information get processed in the brain?
Auditory cortex / temporal lobes
What’s the name of the brain region involved in face detection?
Fusiform gyrus
Damage to the temporal lobes can cause a few different conditions. Name and describe some of them.
Prosopagnosia
Patients can no longer identify people that they previously knew, sometimes even extending to themselves
Visual agnosia
Inability to name or describe visible objects that were once known
What are the two areas associated with language that are described?
What are they each involved in?
Broca’s area - speech production
Wernicke’s area - speech comprehension
Describe and compare the two types of aphasias discussed.
Broca’s aphasia
Unable to produce articulate speech
E.g. Tan, who could only say the word Tan but could otherwise communicate well with gestures
Wernicke’s aphasia
Can produce speech that is fluent but nonsensical.
May use filler words when they can’t find the right word.
What are some of the problems associated with taking a purely neurobiological approach to understanding the brain?
Description is not explanation
Correlation is not causation
We have a variety of evidence that implicates different areas in certain behaviours, but we don’t know why.
May be a modern expression of phrenology - we may know a particular area of the brain is active during certain activities, but we don’t know how it performs it.
The brain doesn’t perform in isolation - behaviours may be a function of complex, brain-wide networks.
What different types of brain cells are there?
What are they called and what do they do?
Neurons
10-100 billion of them in the nervous system
High level of interconnectivity that allows cognitions and behaviours to arise
Communication and processing of information in the nervous system
Glial cells
Different types with different functions
Provide nutrients to neurons and structural support to the nervous system.
What different functions do neurons have?
Sensory neurons
Transmit info from sensory receptors to the brain for processing
Motor neurons
Transmit instructions from the brain to muscles and organs in the body
Can be very long
Interneurons
Transmit info between neurons in the brain
What does the Axon do?
What covers the Axon?
What is it there for?
Carries nerve impulses away from the cell
Transmits electrical signals to the terminal buttons which then transmit across the synapse to the dendrites of the next cell.
Myelin sheath
Allows electrical impules to transmit quickly and efficiently along the cell - protects the impulse from degrading
Where do neurons interact with each other? I.e. What are the relevant parts of the neurons? What is the junction called?
Synapses
Site of transmission of electric nerve impulses between two cells
What are the four types of neuron? Where might you find each other them?
Unipolar neuron
One projectoin from the cell body which can be either a dendrite or an axon, depending on its function
Bipolar neuron
Important role in visual system
Multi-polar neurons
Most common type of neuron in the brain
Pseudo-unipolar neuron
Has only one projection from the cell body, but comprises both dendrites and an axon
Commonly observed as long sensory and motor neurons traversing the length of the body
What is grey matter made up of?
Cell bodies and dendrites of neurons
Where information processing occurs
Located on the outside of the brain
Some large areas deep in the brain
What is white matter?
Contains Axons (nerve fibres)
Most of the inner parts of the brain
Communication between inner and outer areas of grey matter
Spinal cord is also white matter
What is the difference between intra-neuron communication (within a single neuron) and inter-neuron communication (between cells)?
Intra
Step A: ELECTRICAL signal from dendrites and cell body to Axon hillock
Step B: ELECTRICAL signal from Axon Hillock to terminal buttons (action potentials)
Inter
Step C: CHEMICAL signals from terminal buttons of one neuron to dendrites of another neuron across the synapse
What is an ion?
What types are there?
Electrically charged molecule
Can be positively or negatively charged
Cation - positive charge
Anion - negative charge
Found naturally both inside and outside the cell
What are diffusion and electrostatic pressure? How do they work? How do they affect ions?
Diffusion
Passive movement of a substance from an area of high concentration to an area of low concentration
Electrostatic pressure
Passive attraction of oppositely charge ions and repulsion of similarly charge ions
Can make ions move around depending on concentration and / or whether the area has net negative or positive charge. These processes are passive.
What is meant by semi-permeability of the cell membrane?
What make them more or less permeable?
Some things can pass through while others can not.
Opening and closing of ion channels allows certain ions to pass through.
Opening and closing can be controlled by electrostatic stimulation.
What is the resting state of the intra- and extra- cellular space? What is the “resting potential” (both definitionally and specifically)?
Intracellular space has overall negative charge
Extracellular space has overall positive charge
Resting potential = -70mv
What is an excitatory potential?
If electrostatic pressure or diffusion causes the cell to depolarise (become less negative)
What is an inhibitatory potential?
If a cell becomes more negative - hyperpolarised
What happens if a cell receives an inhibitatory potential at the same time as an equally large excitatory potential
They cancel each other out
Where do the graded potentials converge?
Post-synaptic dendrite
What are some differences between graded potentials and action potentials?
Graded potentials
Move from Dendrites to axon hillock
Involve changes in ion concentration and membrane potential
Action potentials = +40mv
Move from axon hillock to terminal buttons
Involve changes in ion concentration and membrane potential
What is the threshold of excitation? What happens when it is reached?
If there is enough excitatory potential, the neuron will ‘fire’ and the signal will continue on to the neurons it is communicating with.
When membrane potential reaches -55 to -65mv
If threshold is not reached, nothing happens.
What are depolarisation, repolarisation, and hyperpolarisation?
When do these happen?
Depolarisation
When an ion becomes less negative
Repolarisation
When an ion regains negativity
Hyperpolarisation
When an ion becomes more negative
Stimulus > depolarisation > threshold of excitation > repolarisation > refractory period / hyperpolarisation > resting state
Refer diagram
Why can action potential only go one way?
There is an inbuilt refractory period in an ion to ensure they do not open in a backwards direction
Where do action potentials occur? What is this process called?
Nodes of Ranvier
Periodic gaps in the myelin sheath of certain neurons to facilitate the rapid conduction of nerve impulses
Saltatory conduction
What is interneuronal communcation?
Chemical interaction that occurs only in the synapse
What are neurotransmitters?
Chemicals that are released by the pre-synaptic neuron to the post-synaptic neuron to cause EPSPs and IPSPs
Glutamate Y-aminobutyric acid (GABA) Dopamine (DA) Serotonin (S-HT) Acetylcholine (ACh) Endorphins
What is a graded potential?
Potential that can vary in amplitude and direction
Whats the relationship between neurotransmitters and graded potentials?
For sensory receptors (e.g. taste, retina) graded potentials in their membranes result in the release of neurotransmitters at synapses with sensory neurons.
What does pre-synaptic and post-synaptic refer to?
Pre-synaptic
Neuron sending the chemical signal
Post-synaptic
Neuron receiving the chemical signal
Where does the decision for a neuron to fire occur?
Axon hillock
What is an EPSP?
Excitatory post-synaptic potential
Depolarises the membrane (makes it more positive)
What is an IPSP?
Inhibitory post-synaptic potential
Polarises the membrane (makes it more negative)
In general terms, hjow do psychoactive chemicals affect our brains (and therefore our experience)?
Either increase or decrease neurotransmitters and their networks
What determines whether a neurotransmitter will bind to a post-synaptic receptor?
Specific neurotransmitters bind to their specific receptors.
‘Lock and key’ principle
Molecular structure of a neurotransmitter can only bind to a receptor that can receive that structure
E.g. Dopamine by dopamine receptors
Do you think inter-neuronal transmission is faster or slower than intra-neuronal communication? Why?
Slower - required chemical reaction, rather than energy transfer?
How do neurons “know” to stop releasing neurotransmitters?
Neurotransmitters can bind to receptors to create a feedback loop that tells the pre-synaptic neuron to stop releasing the neurotransmitter.
All excess neurotransmitter also needs to be removed from the synapse, either by re-uptake sites in the pre-synaptic neuron and / or by degradation by enzymes in the synapse so that the neurotransmitter can be recycled.
In a little more detail now, how can drugs affect our neurotransmission process?
Increase or decrease synthesis of neurotransmitters in the cell.
Alter how much neurotransmitter is released by the cell.
Influence how much neurotransmitter is in the synapse at any one time by manipulating re-uptake of the neurotransmitter or the enzymes that break it down.
Increase or decrease the amount of neurotransmitter receptors in the post-synaptic neuron.
Introduce chemicals that “pretend” to be neurotransmitters with the effect of increasing the number of receptors in the post-synaptic neuron that are activated, or block access to the receptor without activating it
What type of neurotransmitter is glutamate? What is it implicated in?
Most prevalent excitatory neurotransmitter in the nervous system!
Very commonly involved in producing EPSPs in post-synaptic neurons.
Implicated in the pathophysiology of epilepsy and seizures. I.e. Uncontrollable excitation in the brain.
Important for learning and memory; particularly implicated in the forming of long term memories in “long term potential”.
What type of neurotransmitter is GABA? What is it implicated in?
Gamma amino buteric acid
Most prevalent inhibitory neurotransmitter in the brain.
Directly influence by alcohol; alcohol bings to GABA receptors and activates GABA receptor sites; has a molecular structure that can be received by GABA receptors.
What kind of neurotransmitter does alcohol affect and how?
GABA
Involved in inhibition of neuronal fireing; consumption inhibits frontal lobes of the brain which control behaviour.
Excessive consumption can cause the brain to shut down - sleep / coma / death.
Alcohol, Xanax, and Valium all work on what neurotransmitter network?
GABA
They cause reduced activity of the brain and reduced anxiety.
What neurotransmitter and associated network is associated with drugs of dependence? Why might this be the case?
Dopamine
Activates reward pathways in the brain.
They make you feel good!
What kinds of things does dopamine affect in the brain and body?
Emotions
Motivation
Arousal
Movement
What kinds of conditions may be present in those with too much dopamine?
Schizophrenia
Methamphetamines
Cocaine
What happens when you don’t have enough dopamine?
May be a result of Parkinson’s
What symptoms can treatment of schizophrenia cause?
May reduce dopamine and cause symptoms similar to Parkinson’s
Vice versa when treating Parkinson’s - potential for psychotic symptoms to occur
What neurotransmitter is involved in sleep, mood, empathy, and arousal regulation?
Serotonin
Low serotonin = depression
What does MDMA / ecstacy do neurologically? What can this tell us about the role of this neurotransmitter network?
Increases activity of serotonin neurotransmitters.
Causes users to feel a heightened sense of empathy.
What is Actylcholine involved in? What disorder is treated by addressing this network?
Learning, memory, movement, muscle coordiantion
Linked to Alzheimer’s
What role do endorphins play?
Mood
Reducing pain
What drugs are associated with endorphins?
Morphine
Heroin
What is the difference between sensation and perception?
Sensation
Detect information from patterns of physical activity in the environment
Perception
Involves organisation of sensory information into percepts, and integrating them with cognition
Define the term absolute threshold and explain how one might go about estimating this value from a graph of performance (% correct) as a function of stimulus intensity?
Absolute threshold
How much of a stimulus is required for us to detect a sensation
More precisely - the degree of stimulus required to correctly detect that stimulus 50% of the time
Explain the Weber-Fechner (Law) and understand the nature of the relationship between the Weber fraction and the difference threshold
Weber-Fechner Law
It is easier to detect change in low amounts of a stimulus that in high amounts
Equation: delta(i) / i = K
Difference threshold
How much of a difference in stimulus is required to be able to tell that it has changed
Explain the distinction in signal-detection theory between sensitivity and response bias
Sensory sensitivity is limited by the quality of your sense organs
Response bias is someone’s decision making; may be influenced by confidence, motivation, and most importantly the desire to not miss a stimulus versus the desire to avoid incorrectly detecting it
See diagram
What is sensory transduction?
The conversion of physical energy into neural / electrochemical activity. Performed by special class of cells called sensory receptors.
What types of sensory receptors are there?
Simple receptors
Free nerve endings that are simply exposed to the environment.
E.g. Pain and touch receptors
Encapsulated receptors
Coated nerve endings that are more specifically sensitive
E.g. Temperature
Specialised receptors
Nerves with dendrites specialised to detect specific types of stimuli
E.g. Light, sound, smell
Explain the relationship between wavelength of light and perceived colour
Wavelength determines perceived colour
What are rods and cones? Why do we have them?
Two classes of receptors.
Transduce electromagnetic energy (photons of light) into neural activity.
When photons of light strike these receptors, it can result in a chemical reaction with the receptor cell that causes that cell to change its electrical potential.
What are cones?
Three different types, each sensitive to a particular wavelength of light (either blue, green, or red)
More densely situated in the centre of the retina
What are rods?
More sensitive to light, particularly flickering lights
More prevalent at the periphery of the retina
Describe the role the cornea and lens play in focusing light on the rods and cones of the retina
Light is focused (refracted) by the cornea >
Enters the eye through the pupil >
Is refracted again by the lens in order to cast a clear and focused image of objects onto the retina at the back of the eye
What is “accomodation”?
The ability of the lens to adjust its thickness, thereby altering its refractive power
Explain the functional significance of neurons of visual cortex as basic visual feature detectors
Receive and integrate inputs from thalamic cells, giving these neurons complex response properties
I.e. Their activity reflects the combined activities of several thalamic inputs
What are myopia, hyperopia, and presbyopia? What causes them?
Myopia
Short-sightedness
Cornea and / or lens are too strong or eyeball is too large
Hyperopia
Far-sightedness
Cornea and / or lens are too weak or eyeball is too small
Presbyopia
Unable to see nearby objects
Lens is unable to increase its thickness and thereby increase refractive power as an object moves closer
Describe the trichromacy theory and opponent-process theory of colour
Trichromacy theory
Colour we perceive an object to be depends on relative activity of the three types of cones
Relative activity of cones can be uniquely coded for 16 million different colours
Opponent process theory
Colour we perceive depends on relative activity of three pairings of colour-sensitive neurons. Activity of one member of each pair inhibits activity of the other member.
Pairings are red-green, blue-yellow, black-white
Describe the Gestalt organisational principles governing the perception of form
Group features into figure vs ground object perceptions
Group features that are similar in shape into coherent objects
Group features that are close together into coherent shapes
Group features in a way that favours continuity of an object
Fill in apparent gaps between features in order to complete and object
Describe how monocular cues for depth (including pictorial, physiological, and motion cues) can provide information about three dimensions despite our eyes only being able to extract two-dimensional visual information
Pictorial cues: Relative position / height Relative size Linear perspective Light and shadow Interposition / occlusion Aerial perspective or relative clarity
Physiological cues:
Accommodation
Relative movement (motion parallax)
Depth information from utilisation of and comparisons between two eyes
Convergence / divergence - extent to which our eyes need to ‘cross’ in order to focus on one subject
How can binocular disparity provide information about object in three dimensions?
Comparison of visual information between the eyes
Convergence / divergence
What are motion sensitive neurons and how do they account for the beta effect and the phi phenomenon?
Beta effect
Series of still images in quick succession gives the impression of movement
Phi phenomenon
Two separated images that flicker on and offer in alternation
What is the ‘persistence of vision’?
Perception of motion happens automatically, mechanistically, without cognitive intervention, simply because the pattern of visual stimulation activates motion detectors in the cortex
What are the relationships between the amplitude of a sound wave and its perceived intensity, and the frequency of a soundwave and its perceived pitch?
Amplitude
How intensely loud a sound is
High amplitude = louder sound
Frequency
Higher frequency = higher pitch
Humans can hear from 20Hz to 20,000Hz
What is the purpose of hair cells? Where are they located?
Mechanoreceptors sensitive to vibrations
How are the neurons of the auditory cortex process organised?
Hair cells receive vibrations Info is passed to auditory nerves Auditory nerves > brainstem Brainstem > Thalamus Thalamus > auditory cortex (in temporal lobes)
Arranged tonotopically:
Higher pitches trigger neurons towards the back of the brain
Explain the difference between conductive hearing loss and sensorineural hearing loss in terms of the locus of the condition
Conductive
Inability of the tympanic membrane to vibrate
Sensorineural
Damage to hair cells (tinnitus)
Damage to vestibulocochlear nerve
Damage to auditory cortex
How do we perceive the three-dimensional location of a sound?
Binaural neurons - comparison between the two ears.
Compare the frequency theory and the place theory of pitch perception
Frequency
Frequency of oscillation of the basilar membrane corresponds to the soundwave frequency
Direct 1 to 1 correspondence
However hair cells have frequency limits of up to 100Hz
Volley theory
Groups of cells collectively detect frequencies up to 4000Hz
Place theory
Basilar membrane detect different frequencies of sound
Lower frequencies are detected at the apex
Higher frequencies are detected at the base
Detects up to 20,000Hz frequencies
If light is the stimulus for sight, what are the stimuli for smell and taste?
Chemicals on the tongue and olfactory bulbs
What is the process by which smell and taste information is transduced?
Chemoreceptors are specific to particular chemicals.
Lock and key mechanisms - certain receptors respond to certain chemicals
In the cortex, how are taste and smell organised and represented?
See diagram
Taste and smell regions are connected to other areas in your brain. What other regions?
What purpose does this serve?
What impacts does this have on our experiences?
Regions that specialised in processing spatial information.
Strong link to disgust and fear
Identify dangerous or good foods
Recognise friend or foe
What are the body senses?
Touch - somatosensation
Body position - proprioception
Balance - equilibrium
Vestibular areas in the Thalamus and cortex help keep us oriented
Processed by semicircular canals in ears
Pain - nocioception
Processed in multiple places
Need to be able to responde in various ways depending on nature of the pain
How do we experience touch, balance, and pain?
Proprioceptors respond to position movement and strain experience by body parts
What are the receptor types described for the body senses? Where are they located?
Muscle spindle organs
Golgi-tendon organs
How are reflexes processed?
Signals receive an immediate response directly from the spinal cord
What is meant by the gate control theory of pain?
All touch senses compete for perception.
Presence of non-painful touch stimulus can inhibit pain stimulus.
E.g. Holding onto a body part that is experience pain
Why do we integrate perceptual information with cognition?
Perception is the ability to capture, process, and actively make sense of the info that our senses receive.
It is the cognitive process that makes it possible to interpret our surroundings with the stimuli that we receive throughout sensory organs.
What is agnosia?
Inability to process sensory information
What is visual agnosia specifically?
Inability to process visual information
What are the differences between apperceptive and associative visual agnosias?
Apperceptive
Difficulty recognising things due to limitations in integrating visual information into object percepts.
Can be hard to diagnose.
E.g. Can’t achieve object constancy, difficulty identifying objects in cluttered environments, difficulty identifying heavily shadowed objects
Associative
Limited by linking perception with cognition.
Can recognise the outline of an object and deal with object rotation.
Can’t name or classify objects.
E.g. Can’t draw from memory, can’t match objects according to common function
What is prosoagnosia?
Face blindness - can see facial features but can’t recognise who it is
What are the main features of auditoria agnosia and tactile agnosia?
Unawareness of inability
E.g. Stroke patients may not recognise that they are unable to move their arm!
