Cognitive neuropsychology/neurology in theory – functional neuroanatomy

16th June, 2011

Dr Rupert NoadDepartment of Neuropsychology, Derriford Hospital, Plymouthrupert.noad@nhs.net

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 Health

You do not need to be a ‘neuropsychologist’ to do neuropsychological assessment

You 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 Disorders

Degenerative• 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.

**

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 syndrome

Associated 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.

*

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