Cognitive neuropsychology/neurology in theory – functional neuroanatomy
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Transcript of Cognitive neuropsychology/neurology in theory – functional neuroanatomy
Cognitive neuropsychology/neurology in theory – functional neuroanatomy
16th June, 2011
Dr Rupert NoadDepartment of Neuropsychology, Derriford Hospital, [email protected]
MRCPsych Phase IIOlder Persons Mental Health (OPMHS) Module
Plan for the day
10.00 – 11-00 Functional Neuroanatomy
11.00 -11.15 Break 11.15 - 12.30 Cognitive Neuropsychology/Neurology – a clinical
approach 12.30 – 1.00 : Lunch 1.00 – 16.00: Practical Session
Aims and objectives
• Introduction to Neuropsychology• Functional Neuroanatomy• Cognitive disorders• Bedside cognitive assessment• Assessment of dementia
What is Neuropsychology?
• Neuropsychology is concerned with the relationship between brain and behaviour – i.e. how brain functions are organised
• Attempts to understand how mechanisms within the brain influence thinking, learning and emotions
• Neuropsychologists are particularly interested in how brain damage changes behaviour
• This tells us about normal brain functioning e.g. WWI – lots of focal injuries
Neuropsychologists…..
• Aim to apply principles of brain-behaviour relationships to help patients understand their difficulties
• Specialist neuropsychological assessments are used to test patients’ cognition and examine different brain functions
• Neuropsychology knowledge is used as part of a psychological formulation of a patient’s difficulties
Clinical Psychology/Psychiatry understand models of…• Learning• Cognition• Development• Social • Psychodynamics• Scientific paradigms and language
Neuropsychology adds• Biology • Medicine
Neuropsychologists work in….• Acute neurosciences – neurology, neurosurgery• Neuro-rehabilitation – post-acute or community• Older Adults• Learning disability services• Adult Mental Health• Child services• Forensic and HealthYou do not need to be a ‘neuropsychologist’ to do
neuropsychological assessmentYou do not have to do neuropsychological assessment to
think ‘neuropsychologically’
The aim is to…• Have a good understanding of the way brain damage
may impact on someone’s cognition• Have a good understanding of the way cognitive
problems may affects someone's everyday functioning
• What the psychological consequences of a disease may be and how they may manifest
• What other explanations could be causing the cognitive symptoms being reported – in particular psychological difficulties
Child - Why is this child under achieving at school?Adult – Differential diagnosis where neurological
condition is suspected e.g. early onset psychosis versus epilepsy?
Older adult - Differential diagnosis e.g. dementia versus depression?
LD - What is this person’s level of understanding
Other health, forensic, Neurorehab
Where might ‘brain variables’ inform your psychiatric/psychological formulation?
Key ideas• Patient presents with a symptom• You as a neuropsychologist are tasked with the idea
of establishing what is going on• You want to assess their cognition:• Clinical Questions you ask• Tests of their cognition – either bedside or formal
neuropsychological assessment• You do a psychological/psychiatric assessment• You put it all together in a formulation• You discuss this with the patient and base your
treatment plan on this
So you need to be able to?
• Understand their symptoms?• Understand their illness?• Understand the likely psychiatric consequences of
their condition• Ask clinical questions to the patient and carer to
understand their cognition• Gain a useful understanding from observing their
behaviour• Use bedside neuropsychological test to measure
their cognition
The challenge of neurological conditionsUsually complex disorder
involving triad of:• Biological e.g. chorea,
weakness• Cognitive • Psychiatric difficulties
But• Many other secondary
consequences e.g. family dynamics, loss that can underpin individuals’ difficulties
Biological
Psychological Social
How do we understand Neuropsychological disorders?• Functional Neuroanatomy – what bit of brain has been
affected and what does it do?• Cognitive Neuropsychology – how can the patients
symptoms be understood within cognitive models?• Clinical Neurology – what do we know about this disease
– are the symptoms typical?• Clinical Psychology – what do we know about the
disease and its likely psychological consequences? What other factors, lifespan, systemic, childhood, financial etc. might be important?
A practical way of thinking…
• Presence versus absence• Lateralisation• Focal versus diffuse• Acute/progressive versus chronic/static• Aetiology/prognosis/implications
Exercise:
You have an orange, a newspaper and a pencil. How might you use these items to get an idea of someone’s cognitive abilities? What skills do you think you are able to test?
Cognitive abilities• Intelligence• Memory - amnesia• Language – Aphasia, anomia• Executive functions• Apraxia• Attention – hemispheric neglect• Visuospatial ability – agnosia• Other - alexia, agraphia, acalculia, anarithmetrica
Functional Neuroanatomy
How is the brain organised?
frontal
parietal
temporal
occipital
cerebellum
Structural Neuroanatomy
• Atom• Gene• Protein• Organelle• Neuron• Synapse• Neural network• Anatomical regions
Structural Neuroanatomy
• Anatomical regions• Brain stem: medulla, pons, midbrain• Cerebellum• Diencephalon: thalamus/hypothal.• Basal ganglia• Cortex:
– Lobes, gyri, sulci, Brodmann Areas– Limbic system
• White matter tracts• Circulation
Ventricular System
Atrium
Cerebral Aqueduct
4th Ventricle
Pons
Amygdala
3rd Ventricle
Anterior Horn
Posterior Horn
Body
http://www.fisiobrain.com/web/nggallery/page-909/album-6/gallery-12
Brain Spotter Quiz…
Functions of the Frontal Lobe5 key areas:• Motor area• Pre-motor area• Frontal eye fields• Broca’s area• Pre-frontal area (proper)
Important for:Voluntary and planned motor behavioursAll higher order skills – such as executive functions and
personality
Receives major afferents from the dorsomedial nucleus of the thalamus and basal ganglia
Frontal Lobe Syndrome
• 3 Key area in the frontal lobes• Dorsolateral – reasoning, abstract thinking,
problem solving, working memory• Orbitofrontal – social behaviour • Mesial – affect, emotion processing, motivation,
initiation
Frontal lobe DisordersDegenerative• FTD, Picks
Vascular• AnCoA• Subarachnoid haemorrhage
Structural• Major closed head injury
Differentiation from basal ganglia disorders• HD, Advanced PD, PSP, Wilsons disease
Symptoms of frontal Lobe lesions
• Poor planning/organisation• Impaired judgement/reasoning• Poor short-term memory• Difficulty multi-tasking and dividing attention• Behaviour/personality change• Lack of inhibition/inappropriate behaviour• Emotional lability/inappropriate affect • Expressive/motor aphasia
A coronal section through the frontal lobes reveals extensive contusions involving the inferior gyri. This was a contracoup injury from a fall in the bathtub by an elderly person.
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Functions of the Temporal Lobe
TL is involved in Hearing, Memory, Emotional/affective behaviour and Wernicke’s area
Impairments lead to:• Receptive dysphasia (superior) • Memory impairment – left verbal, right non-verbal
(mesial) • Prosopagnosia and poor object recognition (posterior) • Anomia – (anterior) • Hearing deficits. • Hallucinations
Temporal Lobe Disorders
Degenerative• Alzheimer’s disease
Viral• Herpes simplex encephalitis
Structural• Temporal Lobe Epilepsy
Alzheimer's disease leads to cerebral atrophy, characterized by narrowed gyri and widened sulci (mainly frontal and parietal). This is noticeable with dilation of the cerebral ventricles
Functions of the Parietal lobe
• Main role integration of sensory information• From different modalities and to determine
spatial locations of objects. • Important for aspects of somesthetic
sensation (i.e. touch, kinesthesia, pain), taste, and other sophisticated perceptive abilities.
Parietal lobe disorders
Commonly found in:• Stroke• Tumours
Patients experience: • Conduction aphasia and tactile agnosia• Inability to locate and recognize parts of the body
(neglect) – large lesion to non-dominant hemisphere• Severe - inability to recognize self• Disorientation of environment and space• Inability to write (agraphia)• Gerstmann’s syndrome and Balint’s syndrome
Gerstmann’s syndrome
Angular gyrus syndrome
Usually dominant hemisphere stroke
In order of frequency: Dysgraphia Dyscalculia Left-right disorientation Finger agnosia
Gerstmann syndrome
Associated with lesion to the dominant (usually left) parietal lobe
Characterized by four primary symptoms:• Dysgraphia/agraphia• Dyscaluculia/ acalculia• Finger agnosia• Left-right disorientation
Gerstamann’s syndrome
In 1924 he reported case of a 52yr old woman with L sided stroke
Unable to write or calculate
Unable to name/point to her own or examiner’s fingers
Unable to move named fingers
calcarine fissure
Functions of the Occipital Lobe
Involved in sight and processing visual information
Commonly found in:Stroke to posterior circulation
Patient present with:Cortical Blindness
Visual Processing
• First functional area is the primary visual cortex
• This processes low-level information such as local orientation, spatial-frequency and colour then to extra-striate areas for further processing
Balint's syndromeAssociated with bilateral lesions
Characterised by:• Optic Ataxia - inability to accurately reach for objects)• Optic Apraxia – inability to voluntarily guide eye
movements/ change to a new location of visual fixation)• Simultanagnosia - inability to perceive more than one
object at a time, even when in the same place.
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The Thalamus
Thalamus• Is a large mass of grey matter deeply situated in the
forebrain• It relays to the cerebral cortex information received
from diverse brain regions - 'last pit stop' for information before going to cortex
• Axons from every sensory system (except olfaction) synapse here as the last relay site before information reaches the cerebral cortex
• Most commonly impaired in Stroke
Thalamic lesions
• Can cause memory problems• Frontal problems• Speech disturbance
occipital
parietal
frontal
cerebellum
limbic lobe
corpus callosum
thalamus
fornix septum
temporal
hypothalamus
habenula
*paraolfactory gyrus
*orbital gyrus*
olfactory tract*
Limbic System
Involved in:• Emotion• Motivation• Emotion associated with memory• Emotional responses to external stimuli
• Amygdala: Involved in signalling the cortex motivationally significant stimuli e.g reward and fear related
• Hippocampus: formation of long-term memories• Cingulate gyrus: Autonomic functions (heart rate,
blood pressure) +cognitive and attentional processing
• Hypothalamus: ANS regulation via hormones (blood pressure, heart rate, hunger, thirst, sexual arousal, sleep/wake cycle)
Components of the Limbic system
Components of the Limbic System
• Mammilary bodies: Formation of memory• Nucleus acumbens: Reward, pleasure and addition• Orbitofrontal cortex: Required for decision making• Parahippocampal gyrus: Role in the formation of spatial
memory - part of hippocampus• Thalamus: - "relay station" to the cerebral cortex
Hippocampus
• On medial side of the temporal lobe
• Important for converting short term memory to more permanent memory, and for recalling spatial relationships
• Part of the limbic lobe
• Resembles that of a 'seahorse’
Basal Ganglia• A group of nuclei interconnected with cerebral
cortex, thalamus and brainstem• Associated with a variety of functions: motor control,
cognition, emotions and learning• Comprises caudate nucleus, putamen and globus
pallidus • Functionally important for controlling voluntary
movements and establishing postures• Associated with unwanted movements e.g.
Huntington disease or Wilson disease
Basal Ganglia
http://thalamus.wustl.edu/course/cbell6.gif
Frontal-subcortical circuits
• Connect specific regions of the frontal cortex with the basal ganglia and the thalamus in circuits that mediate:
– Motor activity– Eye movements– behaviour
Sub-cortical- frontal pathways…
• Dorsolateral Prefrontal Circuit - executive functions: motor planning, attention, shifting cognitive set, working memory
• Lateral Orbitofrontal Circuit - Emotional life, personality structure, arousal, motivation, affect
• Anterior Cingulate Circuit, Abulia (lack of initiation/will), akinetic mutism
Because of disruption in these pathways, individuals with damage to basal ganglia tend to experience frontal lobe impairments with changes in personality, higher order cognitive functioning and behaviour.
Interconnections – Arcuate Fasciculus – example cortico-
cortical connections)
http://www.fisiobrain.com/web/nggallery/page-909/album-6/gallery-12
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Corpus Callosum
• Enormous bundle of axons which interconnects the left and right cerebral hemispheres.
• Disseminates information from one side of cerebral cortex to same region on other
• Can get disconnection syndromes
Interconnections – Internal Capsule (ascending and descending fibres cortex, brainstem and spinal cord)
http://www.fisiobrain.com/web/nggallery/page-909/album-6/gallery-12
Cerebellum
Important for:• Coordinating voluntary movements (e.g. walking,
posture, speech)• Learning motor (skilled) behaviours. • Like the cerebrum, has a cortex or outer covering of
grey matter.
Cerebellar Disorders
• Spino-cerebellar Ataxia - ? Cognitive problems• Tumours• Stroke
Lots of connections with sub-cortical areas and frontal lobes
Cerebellar affective syndrome?
Midbrain• Tegmentum – contains reticular formation and if
lesioned results in impaired consciousness/coma• Superior colliculus - visual system reflexes• Inferior colliculus - auditory system function• Also has cerebral peduncle – big bundle of axons
involved in motor function• Also contains red nucleus and substantia nigra
involved in motor function
Important for attention and consciousness
Pons
• Contain motor fibres• Important for consciousness and sleep• Lots of links to the cerebellum so if damaged -
get impaired coordination of movement and/or posture.
Medulla
• Contains many sensory (ascending) and motor (descending) tracts (Pyramids).
• Contain nuclei that control respiration, and vagus cranial nerve - important for maintaining open airways and controlling heart rate is located here.
• If medulla compromised - vital functions are compromised.
Break