PSYCH 202: Neuropsychological Methods % Brain Disorders

What is Neuropsychology

The study of the relationship between the brain and behaviour, particularly how brain dysfunction affects cognition, emotion, and behaviour

What is Neuropsychology Why is neuropsychology important for cognitive neuroscience?

It provides evidence about which brain regions are necessary for specific cognitive functions, allowing stronger causal inferences than correlations neuroimaging methods

What is Neuropsychology Wat types of evidence are commonly used in neuropsychology

Observing how naturlly occurring brain damage affects vehaviour and cognition

What is Neuropsychology What is the central question of neuropsychology

How brain structure and function contribute to behaviour and cognition

What is Neuropsychology Why is neuropsychological evidence often stronger than neuroimaging evidence for causality

Because damage to a brain region can demonstrate whether that region is necessary for a function

What is Neuropsychology What is the difference between correlation and causation in brain research

Neuroimaging often shows correlations between brain activity and behaviour, whereas neuropsychology can reveal causal relationships through brain damage

What is Neuropsychology What neurological conditions are commonly studies in neuropsychology

• Stroke

• TBI

• Epilepsy

• Alzheimer’s disease

• Brain tumours

• Neurosurgery

What is Neuropsychology What aspects of functioning can brain disorder affect

• Cognition

• Emotion

• Personality

• Behaviour

• Motor function

What is Neuropsychology Why are cognitive deficits often described as “invisible disabilities”

Because they may not be physically obvious despite significantly affecting daily functioning

What is Neuropsychology What kinds of questions does neuropsychological research address

• Brain-behaviour relationships

• Organisation of cognitive processes

• Effects of neurological disorders

• Development of assessment and rehabilitation methods

What is Neuropsychology How can neuropsychology improve clinical practice

By informing diagnosis, rehabilitation, and understanding of neurological disorders

What is Neuropsychology What is clinical neuropsychology

The assessment and management of individuals with brain dysfunction

What is Neuropsychology What does a clinical neuropsychological evaluation assess

• Cognitive functioning

• Emotional functioning

• Functional abilities

• Areas of strength and weakness

What is Neuropsychology Why are neuropsychological assessments important for rehabilitation

They guide treatment planning and monitor recovery over time

What is Neuropsychology How are neuropsychological assessments used in diagnosis

They help identify conditions such as dementia and mild TBI

What is Neuropsychology How do clinical assessments contribute to research

They improve understanding of brain-behaviour relationships and help develop better assessment tools

Conducting Neuropsychological Research What is a true research design

A design involving random assignment to conditions and manipulation of an IV

Conducting Neuropsychological Research Why are true experiments rarely possible in neuropsychology

Because it would be unethical to deliberately damage people's brains.

• It would require randomly assigning participants to surgical removal of the hippocampus.

Conducting Neuropsychological Research What is a case study

An intensive investigation of a single individual

Conducting Neuropsychological Research What famous cases have shaped neuropsychology

• Phineas Gage

• Henry Molaison

Conducting Neuropsychological Research Advantages of case studies

• study rare conditions

• generate hypotheses

• challenge existing theories

• identify specialised cognitive funcitons

Conducting Neuropsychological Research how has neuroimaging improved case study research

It allows precise localisation of lesions

Conducting Neuropsychological Research major limitation of case studies

limited generalisability

• difficult to establish causality because individual cases may have unique characteristics that are not representative.

Conducting Neuropsychological Research What is a quasi-experimental design

A design that studies naturally occurring groups without random assignments

onducting Neuropsychological Research What is a Region of Interest (ROI) design

Participants are grouped according to lesion location to infer the function of damaged regions

onducting Neuropsychological Research How can researchers study hippocampal contributions to memory using ROI designs

By comparing people with hippocampal to controls without hippocampal damage

onducting Neuropsychological Research Why are ROI designs valuable

They allow investigation of brain function without experimentally causing damage

onducting Neuropsychological Research What is the biggest limitation of ROI designs

Lack of random assignment

onducting Neuropsychological Research Why is lesion variability problematic

Lesions differ in

• size

• exact location

• extent of damage

onducting Neuropsychological Research Why can age of onset affect findings

The brain may reorganise following early damage

onducting Neuropsychological Research Why is selecting an appropriate lesion control group difficult

Different lesions may produce overlapping systems

Different types of Brain Damage What major brain disorders are commonly studied in neuropsychology

• stroke

• head injury

• tumours

• epilepsy

• infectious diseases

• neurodegenerative diseases

Different types of Brain Damage What is focal brain damage

Damage confined to a specific region

Different types of Brain Damage What is diffuse brain damage

Damage spread across multiple brain regions

Different types of Brain Damage What is a stable neurological condition

One where damage does not continue worsening after the initial injury

Different types of Brain Damage What is a progressive neurological condition

One where damage worsens over time

Different types of Brain Damage What is an example of an internally caused brain disorder

Stroke

Different types of Brain Damage What is an example of an externally caused brain disorder

TBI

Stroke (Brain Damage)

A sudden event that causes brain damage

• leading cause of adult disability in NZ

Stroke (Brain Damage) What causes stroke symptoms to qualify as a stroke?

symptoms lasting more than 24hrs

Stroke (Brain Damage) Types of stroke

• haemorrhagic stroke (intracerebral & subarachnoid)

• ischemic stroke

Stroke (Brain Damage) haemorrhagic stroke

Cerebral blood vessel ruptures & blood seeps into, or around, the surrounding neural tissue & damages it

Stroke (Brain Damage) types of haemorrhage stroke

• intracerebral haemorrhage

• subarachnoid haemorrhage

Stroke (Brain Damage) intracerebral haemorrhage

Bleeding directly into brain tissue

Stroke (Brain Damage) Common causes of intracerebral haemorrhage

• hypertension

• head injury

• arteriovenuous malformations (AVMs)

Stroke (Brain Damage) Is intracerebral haemorrrhage usually focal or diffuse

focal

Stroke (Brain Damage) What is a subarachnoid haemorrhage

Bleeding into the subarachnoid space surrounding the brain

Stroke (Brain Damage) Common causes of subarachnoid haemorrhage

• ruptured aneurysm

• AVM

• head injury

Stroke (Brain Damage) is subarachnoid haemorrhage usually focal or diffuse

Usually diffuse

Stroke (Brain Damage) ischaemic stroke

Blockage of a blood vessel leading to reduced blood flow and oxygen

Stroke (Brain Damage) what causes ischaemic stroke

• Embolus

• Thrombus

• atherosclerosis

Stroke (Brain Damage) what is an embolus (ischaemic stroke)

a clot or debris travelling from elsewhere in the body

Stroke (Brain Damage) what is an thrombus (ischaemic stroke)

A clot formed within a cerebral blood vessel

Stroke (Brain Damage) what is an atherosclerosis

Narrowing of blood vessels due to plaque build-up

Stroke (Brain Damage) is ischaemic stroke usually focal or diffuse

Usually focal

Stroke (Brain Damage) Why does ischaemic stroke damage continue developing over 1-2 days

Due to a glutamate-mediated excitotoxic cascade

Stroke (Brain Damage) Outline the steps of the Glutamate Cascade in an ischaemic stroke

• blood vessel blocked

• blood-deprived neurons become overactive - releases glutamate

• glutamate over-activates NMDA receptors in post-synaptic neuron

• Triggers entry of large numbers of Na+ & Ca2+ into synaptic neurons

• Triggers excessive release of glutamate, eventually killing post-synaotic neurons

• Cascade gradually gets weaker

Stroke (Brain Damage) Why does damage spread following ischaemic stroke

Dying neurons release more glutamate, continuing the cascade

Acute Stroke Treatments

• alteplase

• mechanical clot retrieval

Acute Stroke Treatments What is alteplase?

A clot-dissolving drug used in ischaemic stroke

Acute Stroke Treatments When must alteplase be administered

~4.5-6hrs of stroke onset

Acute Stroke Treatments major risk of alteplase

intracranial haemorrhage

Acute Stroke Treatments What is mechanical clot retrieval

Physical removal of a clot using a stent retrieval device

Acute Stroke Treatments treatment window for clot retrieval

~6-7hrs

Acute Stroke Treatments What is infarct core

Brain tissue that is already dead

Acute Stroke Treatments What is the penumbra

Surrounding tissue that is damaged but potentially salvageable if blood flow is restored

Acute Stroke Treatments Why is identifying the penumbra important

It determines whether treatment may save brain tissue