Advanced cognitive Flashcards
How much does a brain weigh?
1.5 kg
Dorsal, caudal, ventral and rostral when referring to the cerebrum and the spinal cord
Cerebrum:
Dorsal is superior
Ventral is inferior
Rostral is anterior
Caudal is posterior
Spinal cord:
Dorsal is posterior
Ventral is anterior
What sections are saggital, coronal and axial (horizontal)?
Saggital - like an arrow in the middle, medial to lateral
Coronal is moving from anterior to posterior
Axial is horizontal so moving superior to inferior
What is the neocortex?
80% of brain volume, the outermost 3mm layer of the brain, 4-6 layers of cells.
What are cytoarchitectonic areas?
Brodmann areas
What are projection areas in neuroanatomy?
The areas of the body that map onto specific areas of the cortex.
What are the association cortices largely responsible for?
‘cognition’ they receive input from primary behaviours and they produce behaviour, they are the ‘higher’ cognitive areas.
Role of the thalamus?
‘relay’ station for sensory processing
Role of the hypothalamus?
Motivated behaviour i.e. eating drinking aggression, sexual behaviour
Role of the limbic system?
Memory, learning and emotional processing
Left hemispheric dominance?
Sequential analysis
Problem solving
language
Right hemispheric dominance?
Visuospatial skills
Emotion functioning - recognising and expressing
Music
Main lateral pathways, in the cerebrum?
Arcuate Fasciculus
Superior longitudinal
Inferior longitudinal
Uncinate fasciculus
Main medial pathways in the cerebrum?
Cingulum
Function of the arcuate fasciculus?
Connects the two language pathways together.
function of the superior longitudinal fasciculus?
Connects the superior frontal lobe to posterior parietal
Function of the inferior longitudinal fasciculus?
Connects inferior temporal to occipital
Function of the uncinate fasciculus?
connects inferior orbital frontal lobe to anterior temporal lobe
Function of the cingulum?
Medial frontal lobe and medial temporal lobe/parahippocampal gyrus
Function of the ventricular system?
- protection, it keeps the brain suspended inside the skull
Layers of the meninges?
Outermost: dura
Arachnoid
Innermost: Pia
main arteries supplying the regions of the brain?
Anterior is supplied by internal carotids
Posterior is Basilar (formed from the vertebral)
Laterally is Middle cerebral
Medially is Anterior cerebral
Occipital and inferior temporal supplied by the posterior cerebral.
What is laterality in neuroscience?
It is the relative theory that the left or right hemisphere is dominant for a certain task.
Findings of John-hughlings Jackson in the 1860s in terms of lateralisation?
Cortical convolutions matured quicker in the left side of the brain.
What are the eight major anatomical differences in right and left hemispheres?
- Right is heavier, left has more grey matter
- structural asymmetry between temporal lobes
- asymmetry (between L and R) in cortex of temporal lobes is correlated with midbrain asymmetry in the thalamus.
- Slope of lateral fissure gentler in LH
- Broca’s area (Frontal Operculum) is organised differently in LH and RH, area visible on the surface is larger in RH, but area in sulci is bigger in left.
- RH extends farther anteriorly, LH farther posteriorly, occipital horns of lateral ventricles 5x more likely to be longer in the RH
- Distribution of neurotransmitters is asymmetrical
- Details affected by sex and handedness.
What is a double dissociation
Two areas of the neocortex are functionally dissociated by two behavioural tests, each test being affected by a lesion in one hemisphere but not the other, e.g.
LH lesions (but not RH) result in deficits in language function (speech, writing, reading)
RH lesions (but not LH) result in deficits in spatial tasks
What is the Wada test (Carotid sodium amobarbital injection)? What would we use now?
Test used to demonstrate which hemisphere is dominant for certain activities. The injection causes anaesthesia in the ipsilateral side.
Nowadays we would use an fMRI
What percentages of R handers and L handers are language dominant in what hemisphere?
98% of RHanded are LHemisphere dominant for language
70% of LH are LH dominant for language
2% of RH are RH dominant for language
15% of LH are RH dominate for language
15% of LH are bilaterally dominant
The results of commissurotomy (split brain) studies?
The role of the corpus callosum is to transfer information to the other hemisphere.
Remember R visual field (in both eyes) processed on left and vice versa.
- Language studies:
In split brain patient does not cross-over (optic chiasm cut)
Cannot say the word banana presented to the Left visual field (right hemisphere), as language is normally processed in the left hemisphere.
Can say the word if presented to the RVF (left hemisphere)
Language is processed in left.
- Spatial studies
An object flashed to a right handed patient can be drawn if presented to the left visual field (right hemisphere) by the non-dominant left hand (I assume also in the right hand - but not sure)
Cannot be drawn if presented to RVF (LH)
RH is responsible for spatial orientation
- Perception studies
Illusory contours (fat/thin squares in circles) when outlines are added, can only be told apart by the right hemisphere (left visual field)
RH is dominant for visuospatial information
- Synthesis studies
Show one word in one hemisphere and one word in another and asked to draw both together.
e.g. arrow shown to right, and bow shown to left.
can do for bow and arrow (insubstantial as it is really common) cannot do for sky scraper.
NO synthesis across hemispheres
Can synthesise in the SAME hemisphere (including right- which is not dominant for language) however they drew different things for example in fire and arm, right drew arm on fire and left drew rifle (language).
Evidence for asymmetry in the auditory system in the brain?
left ear goes to RH, and vice versa
Right ear shows advantage to language sounds
Left ear shows advantage for melodies or musical chords (if a melody id played to both ears you will report the one heard in the left)
Two types of models in terms of theoretical explanations of lateralisation?
Specialisation theories and interaction theories.
Main points of specialisation theories for lateralisation?
Unique functions for each hemisphere
Left is more logical, more analytical, analysing sequentially and then attaches verbal labels.
Right is a synthesiser - it likes to put things together and processes information as a whole
Main points of interaction models for lateralisation?
Propose both hemispheres are able to do all the functions, but they do not (one leads). Three explanations:
- Both function simultaneously, but work on different aspects
- They compete and then inhibit each others activities (would be a drain on resources)
- The two hemispheres receive information preferentially and perform analysis simultaneously but pay attention to different aspects.
What is ‘preferred cognitive mode’?
The preferred use of one thought process over another.
What does cognition mean?
To know or conceptualise - faculty that allows the processing and application of knowledge from the environment. It is a construct of human thought, in forms such as memory attention or language perception. This can also be synthetic. It can be conscious or unconscious.
What is cognitive neuroscience, in a sentence?
Translation of mental processes into behaviour.
What is localisation in cognitive neuroscience?
The idea that certain parts of cognition are specific to certain areas of the brain that serve particular functions.
What are lesion studies?
Studies where a region is deactivated either by electrical stimulation, cooling or chemical. (or I assume in humans on people who have lesions through other reasons)
Advantages are that it can infer causality, however it has disadvantages:
- in animals, it is difficult to apply this
- in humans, lesions are often not one specific area
- in humans it relies on observations from individuals, not lots of data - not very powerful.
What is are PET and fMRI?
PET: positron emission tomography
fMRI you know
They look more holistically at the brain, and are used to localise where something happens (not when).
They rely on two main assumptions
- blood flow will increase when neurones are firing more.
- regional differences in blood flow reflect the level of mental activity
What is the concept of subtraction in fMRI?
I.e. you are doing a study on eye-movement:
Need to measure only eye movements not fixation or noise
Do one with only eye movements, and one with only fixation
Minus fixation and noise from eye-movement
What is EEG?
Electroencephalogram
Measures electrical activity of the brain by measuring it on the scalp.
- Fairly cheap.
- a bit noisy (measuring though scalp and hair)
- 64/128/254 electrodes - more electrodes more accuracy
- Can measure brain waves (alpha, beta, theta, delta and gamma). It is generally very clear disruption in waves, as they are pretty stereotypical for different activities i.e. emotions, sleeping, psychosis, epilepsy.
- Can also measure ERP (event-related-potentials)
- Good for temporal data.
Needs lots of repetitions
What is MEG?
Measures electrical impulses emitted from the brain but through magnetic forces.
More accurate that EEG (for localisation) same for temporal
Has to be done in a shielded room (from earths magnetic field)
Requires expertise to get the analysis
What is TMS?
Transcranial magnetic stimulation
Disrupt a few neurones for milliseconds, by sending in electrical pulse.
Can create virtual lesions
Creates a causal relationship between brain area and function (some others are correlational)
Looking to see if people perform worse
Have to have a control a ‘sham TMS’
Sternberg’s 1999 definition of attention?
Attention acts as a mean to focus limited mental resources, on the most salient information and cognitive processes at a given moment
4 different types of attention and their definitions?
Focused attention: Your ability to single out and respond to stimuli without interference from the environment (noise)
Sustained attention: your ability to maintain focus on a task or behaviour during a continuous or repeated stimulus.
Selective attention: your ability to filter out distracting stimuli while maintaining attention on one source of information
Divided attention: Your ability to split your attention between tasks (usually two)
Two ways in which you shift your attention to visual stimuli? (attentional shift)
Overtly - obviously, move head and eyes to another space
Covertly - when you shift your attention without moving your head or eyes.
Two different types of attention?
Exogenous - something grabs your attention (big flash)
Endogenous - voluntary shift to another area
Three types of theories of attention?
Broadbent (1957) - Early selection
Deutsch and Deutsch (1963) - Late selection
Treisman (1964) - Early selection
What was Broadbent’s early selection model?
Sensory info comes in
Stored in short storage (sensory)
Put into a working memory
The stimulus is either (i) put into long term storage or (ii) responded to.
What is Deutsch and Deutsch’s model?
Discovered that we can also remember things we are not asked to focus on - either things slip through or attention isn’t as focused as Broadbent thought.
Late selection:
- Info comes through into sensory info
- It is then put through an analysing mechanism
- it is then put into memory
- this is then either (i) attended to or (ii) left according to pertinence (which is made up of expectations and language)
What is Treisman’s (1964) model?
Attenuation model:
Can happen early, there is a system that attenuates info:
- info comes through to sensory buffer
- then goes through an attenuated process, some info if given more attention than others
- more likely to be put into short term if it has been attenuated to.
What terminology does (i) vision and (ii) audition use to describe attention?
Vision: spotlight or zoom-lens
Audition: Filter or bottleneck
EEG evidence for early selection theories?
Do dichotic listening task - there is a N1 peak in activity in the hemisphere for the attended to ear 20-50ms, which is very early on. also seen at 60ms in P1
An example for object based attention (and late selection I think)
Visual illusions - you must use higher cortical areas, if it was early you wouldn’t expect our perception to be affected.
fMRI evidence for late selectionist theories?
O’Craven et al 1999, presented an image of a face and a house merged on top of each other, found that the fusiform face area is activated when attending to the face and parahippocampal place area.
Both are quite far downstream, evidence for late selection.
What is ‘the binding problem’ in attention?
So different features of the visual scene are coded for by different systems i.e. direction of motion, colour and orientation. We know this through anatomical, neuroimaging and neurophysiological studies
It’s not completely understood how we experience a coherent world
The feature integration model may help to explain this
What is feature integration theory? (full explanation)
The idea that sensory features (orientation, colour etc) are all coded for in parallel by specialised modules.
These modules form two types of ‘maps’:
- Feature maps i.e a colour map, an orientation map
- A master map of locations - all the possible locations in the environment (the feature map is placed within this)
Visual attention is used for:
- locating features
- binding features together
The maps contain two kinds of info:
- presence of a feature anywhere in the visual field
- implicit spatial info about the feature
Two stages:
Preattentive: not using attention, just identifying features of that object in parallel
Attentive: the binding stage, where attention is focused to one area of the field - local features are combined to form a whole
An exogenous, type of attention is top down or bottom up?
Bottom up - using sensory info to bring about attention
An endogenous, type of attention is top down or bottom up?
Top down - using cognitive circuitry to drive the attention
Attention evidence from pts with hemispatial neglect? and those with hemianopia?
Hemispatial neglect:
Damage to right posterior parietal cortex.
Cannot attend to left visual field, however they can see them when they are pointed out.
Hemianopia:
Are aware of objects - but cannot SEE them
Parietal lobes important in attention
Attention evidence form pts with blaints syndrome
bilateral parietal lesions
Simultanagnosia: cannot see the scene as a whole, but only individual areas
Occulomotor apraxia: inability to voluntarily move the eyes, or refixate to a new point of interest
The reflexive system is still intact, however endogenous is not functioning - parietal lobes are important in endogenous attention
Dorsal and ventral stream evidence regarding attention?
Dorsal stream involved in ‘where’ - parietal lesions cannot indicate where an object is
Ventral involved in ‘what’ - temporal lesions cannot indicate what an object is
Frontal lobe involvement in attention?
May be involved in the integration of memory in the attention system. Hopfinger et al.
What is ‘inhibition of return’? What does this tell us about attention?
It is the fact that we have a delay in our ability to return to an object that has just been attended to. At first attention is fast (100-300ms), (facilitation) but at return it is low (500ms-3000ms) (IOR).
Part of the exogenous system of attention, I guess to enhance the presentation of new stimuli.
what areas do the exogenous and endogenous systems occur (dorsal or ventral)?
Exogenous is more ventral
Endogenous is more dorsal
Change blindness and it’s relation to attention?
We are very bad at noticing changes that occur in our field, shows we do not focus on all areas, but have focus attention or divided attention.
Function of ‘sensory memory’? Capacity, duration?
Hold sensation for long enough for you to put it in a ‘buffer’ Large capacity, small duration
Function of short term memory? Capacity, duration?
Hold the perceptions for long enough for you to be able to process them further, 30 second duration 5-9 unit capacity
Function of long term memory? Capacity, duration?
Permanent storage of info, permanent duration and unlimited capacity.
What is working memory?
A type of memory that requires ‘active’ processes in remembering - manipulating info i.e. remember this number and then repeat it back to me backwards.
fMRI findings regarding verbal semantic STM in remembering and forgetting
Left 45/47 area active (ventrolateral prefrontal) involved in semantic processing, specifically activated when remembering vs forgetting.
Areas responsible for semantic processing vs phonological processing?
Phonological - broca’s area (44)
Semantic word processing is again 45/47
TMS Findings regarding visual working memory areas in the brain?
Double dissociation suggesting that the parietal lobe is responsible for visual memory of objects, and that the temporal is for visual memory of faces.
Different types of visual memory tasks?
Maintenance only tasks - short term memory tasks:
- Digit span forward, asked to recite
- Delayed match-to-sample (was it the same)
- Delayed response (click on screen)
Maintenance and manipulation tasks - working memory
- Digit span backward
- N-back (ie 1 back, 2 back or 3)
- Mental arithmetic
What did Gnat and Anderson (1988) show?
How did Oyachi and Otsuka (1994) develop this?
Measured PPC activity during delay of memory guided saccade task - decrease in activity as they make their response.
Compared 1000ms delay and 200ms delay. There is sustained activity in the 1000ms - suggests the PPC is responsible for spatial memory
Oyach and Otsuka showed that it was the right PPC specifically through the use of TMS stimulation
Specialist brain areas involved in visual memory for faces and places?
Parahippocampal place area - places
Fusiform face area - faces
Area of the brain responsible for visual memory of body parts?
Extra-striate body area
Area of the brain responsible for visual memory of moving vs static objects
MT or V5
Evidence regarding the ventral temporal cortex and neurones for specific colours?
In a delay task (where you have to recall) there are specific neurones that are more active when remembering this colour - shows there are specific areas of the brain responsible for specific parts of objects
Difference in Dorso-lateral PFC, and Ventrolateral PFC?
Dorso - spatial memory and manipulation
Ventro - Object and maintenance
What is long term potentiation
When two neurones meet and restructure to engage more efficient communication. Happens in long term memory.
How is LTM organized?
Logically - as a network or map of associations between memories
Types of LTM?
Explicit (aware) - semantic or episodic
Implicit (unaware) - priming or procedural
Two types of procedures to test semantic and episodic memory?
Free recall
Recognition
Areas of the brain often associated with LTM?
Limbic system - hippocampus and amygdala
PFC - explicit LTM, but NOT implicit - needs WM system
Evidence for explicit and implicit memory separation, and hippocampus?
HM - no hippocampus, can form implicit memories
Rats with ablated hippocampi cannot learn water maze task
evidence regarding taxi drivers and changes in hippocampus size?
Larger posterior hippocampus but smaller anterior hippocampus.
Age differences in memory for negative stimuli?
Younger adults have higher amygdala activity in response to negative stimuli - therefore higher hippocampal activity, and it is better remembered.
What is priming?
Implict LTM - basically alteration to response following exposure to a stimuli.
What area of the brain is engaged in implicit LTM?
The cerebellum.
What is long-term potentiation, habituation and sensitisation?
LTP - increase in excitability over a long time, due to repeated synaptic input.
Habituation - when an individual ceases to respond to a stimulus after it has repeatedly occurred over a prolonged period of time.
Sensitisation - Strengthening of a response to a stimulus due to the response of a second stimulus.
What is affective neuroscience?
Understand the emotional aspects of brain function through objective physical measures.
What is psychophysiology?
The idea of verifying and quantifying emotional reaction when self-report is not available or reliable…
Pupil dilatation
Sweating
Startle response
Heart rate
Divisions of the nervous system?
Nervous system:
- Central
- Peripheral
Peripheral is:
- Autonomic
- Skeletal
Autonomic is:
- Sympathetic
- Parasympathetic
Orbito-frontal cortex role?
Planning and emotion.
Components of an emotional response?
Behaviour, autonomic activity and hormonal secretions
What are the ‘primary human expressions’?
Surprise, anger, fear, disgust, happiness and sadness
Evidence regarding lateralisation in emotion?
The right hemisphere is more ‘emotional’ than the left.
if you damage the RH you get:
- decreased facial expressions and spontaneous speech.
What is James (1884) Lange (1887) theory of emotional processing?
In the example of a bear:
- we see a bear
- Physiological reaction (i.e. run)
- Feeling of fear
We feel fear because we run.
Cannon-bard theory of emotional processing?
Did work on decorticate animals (cut the connection between higher cortical ares and brainstem)
Decorticate animals still exhibit rage
Stimulating hypothalamus induces rage
Argued that the physiological reactions and the feeling of fear run in parallel but are not connected.
Components of the limbic system?
Hypothalamus Amygdala Hippocampus Cingulate cortex Orbito-frontal cortex
Function of the limbic system (thought and feeling)?
It is the connection between thought and feeling.
Thought is emotions experienced consciously through the actions of the limbic system on the cortex
Feeling is emotion through actions of other regions (OFC) on the limbic system
Evidence for the function of the limbic system?
Kluver-Bucy syndrome:
Removal of the anterior temporal lobes of monkeys (amygdala), this increases:
- eating
- sexual behaviour
- visual agnosia
- lack of fear response - no connection to the cortex to those hindbrain parts, shows the importance of the limbic system in linking cortex to hindbrain
In humans:
- emotional blunting
- hyperphagia - excessive eating
- inappropriate sexual behaviour
- visual agnosia
What is the biopsychological view of emotion processing
The modern view, the biopsychological view:
As a circuit:
- perception of bear - feeling of fear -physiological reactions -
Can contribute to each other
Bodily feedback can modulate the perception of emotion
Two modern takes on emotion processing?
Both are within the biopsychological view:
- Somatic marker hypothesis (damasio):
- based largely on James-Lange theory, however it’s not so rigid, not only when we express an emotion do we feel it
Memories of emotion can lead to ‘as if’ states - pre-
feeling, imagining can lead to expression of emotion (similar to James-Lange) interoception
Stresses biological importance of certain stimuli - gut feelings in decision making.
- Cognitive-emotional (social) interaction - LeDoux:
- Cognition and emotion are overlapping systems
- Fear in animals helps them survive but causes stress in humans, how we have adapted to survive this
- studies using fear conditioning model.
Evidence for VMPFC involvement in the somatic marker hypothesis from the iowa gambling test?
IGT: Two packs of cards - A with low immediate return but decent over time, B with high immediate return but long term loss. Most people switch to B but then switch back to A
People with VMPFC will switch to B and stay there.
Shows they are poor decision making.
Can’t recall previous emotional states (the pre-states to influence our decision making)
Lateralisation of the PFC?
Left PFC:
- Mediates positive mood and approach
- Underactivity or damage leads to withdrawal and depression
Right PFC:
- Mediates negative mood
- Underactivity/damage can lead to euphoria and decreased pain
Cortisol involvement in PTSD?
Upregulate cortisol receptors in:
- Hippocampus - memories
- Amygdala - emotion
- PFC - attention and dual-tasking
Evidence regarding decerebration in animals and food intake?
The hindbrain by itself will have all the necessary circuitry to chew, swallow
Three attributes of the neural system of food intake?
- Wired in reflex system (hindbrain)
- Complex and widely distributed - many circuits are responsible, not just hindbrain
- Lots of redundancy (circuits doing the same thing) - because it is so important
Summary of the appetite control system in the brain?
Input of sensory information
- Sight, smell, touch, sound and taste
- Nutrient signals generated from pre-ingestion to oxidation
Neural integration:
- Bottom up, top down processes
Appetitive output:
- Behaviour (motor)
- Endocrine and autonomic
What are cephalic phase responses?
The pre-ingestion responses to seeing food:
- Salivation
- Secretion of insulin
How do GI hormones signal the brain?
- Through the vagus nerve - NST
2. Pass the BBB - ARC
What is the nucleus of the solitary tract? What does it do?
The area in the hindbrain (medulla) responsible for integration of signals (nervous) from oral cavity, GI tract and liver.
Co-ordinates the reflex responses of the brain
The signals project out to the Lateral Hypothalamic area
Long-term regulators of appetite control?
Tonic signals (always there in the blood-stream), these are things like insulin and leptin.
Insulin secreted by the pancreas, leptin released by leptin.
Both Insulin and Leptin pass through the BBB
Act on the Arcuate nucleus in the hypothalamus
Actions are similar as they inhibit NPY and AgRP neurones, and stimulate POMC and CART neurones.
NPY and AgRP stimulate food intake, PMC and CART do the opposite.
What are the effects of high levels of leptin and insulin in obese people?
They don’t really have satiety effects.
What happens when tonic signalling is low, in terms of satiety?
Tonic signals low - low body fat
The episodic signals become weakened or ineffective - means you will keep on eating
What is the homeostatic model of food intake regulation?
A bottom up model of food intake.
Signals come from leptin/insulin in the liver and also from the GI tract and these are then received and processed in the CNS by several different components - such as areas in the hypothalamus.
How is the neural architecture for appetite structured in the hypothalamus?
EARLY THEORIES:
Lateral hypothalamus control hunger
Ventromedial controls satiety
SPECIFICALLY:
Firstly there are neurones in the arcuate nucleus (ARC) (first order): (Receive info from the nucleus of the solitary tract)
- AgRP/NPY - stimulate appetite
- POMC/CART - inhibit appetite
The second order neurones:
- Paraventricular nucleus: Neuroendocrine and autonomic responses
- Ventromedial Hypothalamus: Satiety and motivation
- Lateral Hypothalamic Area: Behavioural/cognitive responses.
What does the Lateral hypothalamus receive and communicate with?
Bottum up lower order signals ARC and NST
ALSO projects and receives input from higher cortical areas, involved in memory, learning reward and motivation. PFC, Cortex, limbic system, and Nucleus accumbens (reward)
Components of food reward (psychobiology)?
Learning aspect
- classical conditioning (implicit)
- action-outcome recommendations (we know we will enjoy pizza) - (explicit)
Liking aspect
- Core affect (implicit) - muscle spasms and stuff
- Experienced/anticipated pleasure (explicit)
Wanting aspect:
- Motivational attraction ‘wanting’ (implicit) - unconscious
- Cognitive attraction ‘wanting’ (explicit) - conscious, deliberate
Pickens et al (2003) evidence regarding neurological architecture involved in the representations of food?
Conditioned a neutral taste with a positive or negative stimuli.
complementary roles of the basolateral amygdala and the orbitofrontal cortex.
BLA - Involved in acquisition of outcome representations
OFC - involved in the memory of outcome representations
What did Mcclure et al 2004 show?
We are more likely to choose a food that we have an emotional component to - frosties tiger
What is the taste reactivity paradigm?
A measure of how much an animal (mouse) likes a certain substance. Coded video recordings. Looking at behaviour and facial response. Produce a taxonomy of responses
Neural circuits for implicit liking?
Neurotransmitters involved
Important areas in the hindbrain, nucleus accumbens and ventral tegmental area
Opioids highly involved in implicit liking:
- Opioids released in response to palatable but not bland food
- opioid antagonist (naltrexone) will increase consumption of palatable food.
Hedonic hotspots in the Nucleus accumbens shell
Neural substrate for explicit liking, and neuroanatomical areas?
Orbito-frontal cortex, and cingulate cortex.
Makes sense as these areas are part of the opioidergic pathway - but the higher areas.
Neural substrate and pathway for implicit wanting?
Evidence?
dopamine
Ventral tegmental area (VTA) - Nucleus accumbens.
Can wipe out wanting areas and then give liking opioids and get model to eat food. And vice-versa.
Theories relating to obesity and the wanting response?
Evidence
Sub-optimal functioning of the neural pathways relating to reward may lead to an individual ‘self-medicating’ . with increased food intake, in order to increase activity in those areas.
Wang et el 2001 measured dopamine receptor availability in obese and lean individuals. Found there is much less dopamine receptor availability in obese individuals - and not related to metabolic activity. When just looking at obese individuals the bigger they were (BMI) then the less dopamine
What neural systems regulate the top-down regulation of food intake?
The PFC mediating the responses of corticolimbic areas
Right PFC related to restraint and self-control
Successful dieters show greater right frontal cortex activation than controls
Three overall control mechanisms relating to food intake?
Higher inhibitory control
Hedonics and reward - learning memory
Homeostasis - neuroendocrine mechanisms
What are the 4 levels that make up the structure of language?
Phonology: How sounds combine to make words
Morphology: how words are made, made up of morphenes, free and bound morphenes. e.g. plural ‘s’ attaches to desk to make desks
Syntax: How words combine to make sentences: rules and order, in english: subject verb object.
Semantics: the meaning of words
What techniques can we use to study language?
Lesions: human patients
Brain-stimulation studies:
- during epilepsy operation
Functional neuroimaging studies:
- using subtraction method.
What is aphasia?
Language deficit caused by damage to the brain
What can cause aphasia?
CVA - Cerebrovascular accident caused by embolism, thrombosis or haemorrhage - for language in the MCA.
TBI - traumatic brain injury
Space occupying lesion - tumour
Infection and inflammation
Does aphasia affect a persons intelligence?
No people with aphasia do not lose ideas and thoughts, just lose access to them.
Areas where Broca’s patient ‘tan’ had damage in the brain?
Pars opercularis, insula and lower motor cortex
What is non-fluent aphasia (broca’s aphasia)?
Expressive aphasia:
- Speech is halting, slow
- Speech timing is disturbed (dysprosody)
- Bound morphemes are missing
- Phonemic paraphasias - mistake with the sound
- Relatively spared comprehension
- Aware of their mistakes
What did caplan and Hildebrand (1988) show about aphasic patients?
Showed that the deficit was grammatical - agrammatism
Not production
It is a loss of syntactic knowledge
Differences in Wernicke’s aphasia (receptive aphasia)? What features are there?
No motor deficit
Able to speak, although what he said did not make sense.
Not able to understand verbal or written words
Lesion was in posterior temporal/parietal area
Features:
- Semantic paraphasia (chair for table)
- Phonemic paraphasia (plick for click)
- Neologisms - made up words
- Intonation and grammar are preserved.
A lesion in teh arcuate fasciculus will result in what?
Conduction aphasia - repetition is impaired
Does a lesion in brocas area always result in broca’s aphasia?
Not always - this also goes for Wernicke’s area.
Evidence from brain stimulation studies in aphasia?
Rassmusen & Milner (1975)
Found speech arrest in a very specific area in the anterior part (Broca’s) - well localised
This is much more diffuse in the posterior area (wernicke’s)
2 main types of effects gained from stimulation of broca’s, wernicke’s, face motor area, face sensory area, supplementary area?
Positive - say something ‘ohhhh’
Negative - (speech arrest - cannot speak)
What role does the Right Hemisphere play in language?
Understanding alternative meanings for things
Understanding Jokes
Understanding the gist of stories
Making inferences
Understanding prosody
PET activiation when (i) passively viewing words (ii) listening to words, (iii) speaking words and (iv) generating word associations.
i - Occipital areas - seeing
ii- Temporal lobe - auditory cortices
iii - Motor stream
iv - engage language areas, broca’s and wernicke’s
Different Language ERP components elicited in EEG?
P300 - elicited by surprising events
N400 - Meaningful stimuli
P600 - Ungrammatical stimuli (related to P300) - mistakes
Why is language lateralised?
So that processing can go smoothly - one isn’t dominant. Linked to handedness.
General physical biological changes in ageing?
Increased susceptibility to infection
Decreased lung capacity
Muscloskeletal decline
CVS: size of heart increases, increased collagen in blood vessels (less elasticity), increased blood pressure
Normal sensory changes in ageing?
Vision:
- cornea flattens
- lens transparency decreases
- less efficient retina (reduced blood-flow and UV exposure)
- reduced lens elasticity - age-related long sightedness - presbyopia
Hearing:
- eardrum becomes less flexible and ossicles (bones) become stiffer
- Presbycusis - old mans hearing - decreased perception of higher frequencies, and speech discrimination.
Taste and touch decrease.
Abnormal age-related vision conditions?
Abnormal age-related conditions:
Macula degeneration: Cell death within the fovea - central vision not seen
Cataracts
Glaucoma - pressure on the optic nerve - will reduce peripheral vision.
Anatomical changes within the brain with ageing?
Gross brain atrophy
Ventricular enlargement
Selective, regional neuronal loss
Deterioration in axons and dendrites
Increased in senile plaques (dead cells - amyloid B) and neurofibrillary tangles of Tau
Decrease in neurotransmitters
Decrease in cerebral blood flow
Decreased cerebral metabolic rate
Evidence for the genetic relationship on ageing?
Siblings and children of centenerians seem to live longer
Monozygotic twins likely to live similar lengths compared to dizygotic twins
Evidence for calorie restriction on ageing?
Calorie restriction extends life in a series of models (flies up to cows)
What positive changes in functioning increase in ageing?
More knowledge
Better at managing info, isolating and identifying knowledge
Better at extracting meaning
Vocabulary increases
Up to 40 numerical ability increases
Common sense increases
form Judgements and arguments increases
Functional abilities that decline in age?
Verbal memory Spatial orientation Perceptual speed Inductive reasoning Working memory Increases in learning times
What happens to attention in increasing age?
Attention is not all equal in age.
Selective - not too affected
Divided - does become a problem
Sustained - Not a problem, unless distractions are included
Why does divided attention specifically decrease in age?
Adults are not so good at adapting to a new situation. Divided attention tends to use a bottom-up approach. Bottom up processes are affected by ageing
Could be looked at in terms of crystalline intelligence and fluid intelligence. Fluid intelligence decreases in older age.
Plasticity in ageing?
Cognitive decline in ageing may not be due to cell death.
Older people may use plasticity to recruit other areas (i.e. other hemisphere) to do the jobs of declining areas.
When there is a decline in plasticity this may cause issues
Michael Ramscar’s theory on decline in ageing?
Computation theories, thinks that decline is because teh brain gets filled up with space - like a computer cannot retrieve things so easily.
Professor Larraine Taylor theory of decline in ageing?
Plasticity theory - deals with actual brain
Three stages when forgetting can happen?
- Encoding stage
- Storage stage
- Retrieval stage
Role of the ventrolateral prefrontal cortex and the parahippocampus at the encoding stage of memory?
Ventrolateral prefrontal cortex - selects which items to attend to during encoding
Parahippocampus - reveals higher activity to an item that is later recognised - has some role
4 subtypes of retrieval stage (of remembering)?
- Recall - passive
- Recollection
- Recognition
- Relearning - active, relearning
Normal age-related forgetting?
Forgetting where you left things Forgetting names of acquaintances Forgetting appointments Forgetting details of conversations ToT phenomena
Difference in episodic and priming memory in age?
priming stays fairly constant
Episodic increases up to 30/40 then declines
relationship between ages in education and dementia?
More years in education means less likely to develop dementia.
How does ageing affect the cerebellum?
Cerebellum good for motor memory (implicit memory)
Is quite preserved
How does ageing affect the hippocampus?
Declines in age - atrophy
impairment in memory and consolidation
Park and Reuter-Lorenz (2009) study on brain volume and age?
Some areas reduced in volume due to age, some did not:
Reduced:
- Caudate nucleus
- Prefrontal cortex
- Cerebellar hemispheres
- Hippocampus
Unaffected:
- Primary visual cortex
- Entorhinal cortex - sensory
However lots of individual differences.
Compensatory mechanisms in age
More neurogenesis
Recruit other areas
Bilaterality
recruit PFC more
What is mild cognitive impairment?
Affects daily life but stops short of dementia, not necessarily a precursor to dementia.
Can maintain independent living
50% will develop dementia, 50% won’t
Main differences in normal memory loss and dementia
Dementia will not complain about it, you will observe, normal people will complain
Dementia may frequently forget words and common ones. Normal ageing may occassionally forget
Dementia may get lost on familiar places normal may pause but not get lost
In dementia interpersonal skills may decline - may withdraw from community
Relationship between attitude and memory decline?
Positive attitude = better cognitive performance.
What waves are prominent during sleep in EEG?
Theta
When are alpha waves present in EEG?
During resting wakefulness
Is the parietal lobe involved in speech?
Nope
What lobe is important for emotional functional processing?
Temporal
Is the posterior parietal cortex more involved in visuo-spatial or visuo-object tasks?
Visuo-spatial
Damage to what area of the brain would cause more errors in saccadic spatial localization?
The right PPC (posterior parietal)
Who first introduced the idea that we needed to focus on one single item?
Herman von Helmholtz
Who published the expression of the emotion of man and animals?
Darwin
What is dysprosody?
Failure in the rhythm, intonation and melody of speech, occurs in non-fluent aphasia
What are neologisms?
Invention of new words
Delta EEG waves?
Seen in slow-wave sleep
Alpha EEG waves?
Basic wave - normal
Beta EEG waves?
Anxiety
Gamma EEG waves?
Binding together, cognitive or motor functions
Gazzaniga (1998) findings regarding spatial attention and commisurotomy patients?
(Holtzman 1980) Attentional system is common to both hemispheres - in regards to spatial attention
What do split brain ptps perform better on than non-split patients?
Searching a visual field for a specific pattern or object. Intact brain appears to inhibit the natural search processes the brain possesses
Differences highlighted by Gazzaniga in human and monkey ‘split brains’
Monkeys can still transfer visual info through the anterior commisure - humans cannot.
What did Gazzaniga (1998) find regarding the capacity of the right brain for language and implication for writing?
The right brain possesses very little capacity for language, however much individual variation is seen here, and there is some evidence for plasticity as some patients (JW) developed the ability to speak from the right.
Another patient used language from her left hemisphere, and wrote from her right - suggesting that writing is a cognitive function that can stand alone, and is not integrally linked to language.
Evidence regarding lateralisation and false memories?
The left hemisphere shows origins in the creation of false memories.
This may be because the left hemisphere has the ability to determine the source of a memory, and the wider context it is presented in
