Transcript Psychology and neuroscience (W)

PS1009
Applied Psychology
Psychology and neuroscience
Dr. Andrew Young
Behavioural Neuroscience Group
[email protected]
Psychology and brain function
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• As psychologists we study the interaction between an
organism and its environment
• Perceiving the environment (sensory perception)
The Brain
Integration
Decision
Transmission
• Behavioural responses
Neuronal connectivity
Chemicals
(Neurotransmitters)
Neurones
Electrical activity
Brain function and behaviour
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Paul Broca (c1860)
• Studied a patient called ‘Leborgne’
• intelligent and capable of comprehending spoken and
written language
• but unable to speak more than a very few meaningless
syllables for 21 years
• capable of communication using motor gestures
Post-mortem study of brain showed:
• single lesion towards back of left
frontal lobe
• first evidence for highly localised
control of function in the cortex
Types of measurement
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• Post-mortem studies
• Provides anatomical information
• Of limited value for functional studies
• Living neurones in isolation (in vitro - e.g. cultures, slices)
• Show how living neurones can function
• But give limited information on behaviour
• Studies intact brains
• Effects of brain injury on behaviour
• Effects of drugs with known pharmacology on behaviour
• Monitoring brain activity during behaviour
• Underpinned by post-mortem and in vitro studies
Study of normal brain function
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Perception – vision, sight, smell, taste *
Movement *
Language
• Neuronal systems involved – e.g. hippocampus *
Learning and memory • Electrical process involved – e.g. LTP *
• Neurotransmitters involved – e.g. glutamate *
Sleep
Pain and analgesia
(* see PS1003 lectures)
Mood
Personality
….. many more
Study of abnormal function
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• Studying neuronal processes and/or neurotransmitters involved in
• Perceptual disorders
• Motor disorders
• Schizophrenia
• Depression
• Anxiety
• Parkinson’s disease
• Ischaemia (stroke)
• Epilepsy
• Addiction
• ….. many others
Symptoms of psychosis
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Abnormal ideas :
• delusions (mood, persecution, grandiose, hypochondriacal)
Abnormal perceptions :
• hallucinations (mainly auditory)
Formal thought disorder :
• derailment, loss of goal, neologisms, poverty of speech content
Motor, volition and behavioural disorder :
• catatonia, abnormal posture, avolition, mutism,
Emotional disorders :
• affective flattening, emotional withdrawal, anhedonia.
Difficult to measure objectively
Can psychology help us understand schizophrenia?
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Understanding biological basis of psychological function
- relationship with dysfunction in psychiatric disease
• effects of brain injury on behaviour
• effects of drugs on behaviour
• pharmacology of drugs with therapeutic effects
• studies with tasks which rely certain brain areas
• brain imaging studies, especially function in these tasks
• use of animal models of psychological function
Effects of brain injury on behaviour
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• Temporal lobe dysfunction (e.g. temporal lobe epilepsy)
• Can lead to some symptoms
similar to positive symptoms
of schizophrenia.
• Frontal lobe damage
(e.g.frontal lobectomy)
• Leads to symptoms similar
to negative symptoms of
schizophrenia.
Effects of drugs on behaviour
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Several drugs known to cause symptoms similar to schizophrenia:
• Amphetamine – causes hallucinations and delusions very
similar to positive symptoms of schizophrenia
• Are positive symptoms associated with increased dopamine?
• LSD – causes hallucinations which are similar the positive
symptoms of schizophrenia
• Are positive symptoms associated with increased serotonin?
Pharmacology of drugs with therapeutic effect
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• Classical (‘typical’) antipsychotic drugs
• Antagonists at dopamine receptors
• Newer (‘atypical’) antipsychotic drugs
• Antagonists at both dopamine and serotonin receptors
Dopamine and serotonin over-activity both
implicated in schizophrenia.
Studies using tasks relying on certain brain areas
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• Positively symptomatic schizophrenics are deficient in tasks
requiring temporal lobe function
• e.g. selective attention
– latent inhibition (learning to ignore irrelevant stimuli)
• Schizophrenics are deficient in tasks requiring frontal lobe
function
• e.g. Wisconsin card sort, Tower of Hanoi
• First degree relatives of schizophrenics are also deficient in
frontal lobe tasks.
Brain imaging studies
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• Functional magnetic resonance imaging (fMRI) studies have
looked at brain areas activated during these tasks:
• e.g. Latent inhibition
-2
Z-coordinate of slice
4
9
Right
Left
Young AMJ et al., 2005
• How does this differ in schizophrenic patients?
Animal models of psychological function
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Latent inhibition in animals – relationship with schizophrenia
Learning
SALINE
AMPH
AMPH +HAL
Schizophrenia
Poor
LI
Good
NON-PREEXPOSED
PREEXPOSED
Latent inhibition provides a model for studying the
neural basis of schizophrenia
Information processing deficits in schizophrenia
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Kraepelin (1913)
"Schizophrenic patients are unable to exclude irrelevant
sensory information from their awareness"
McGhie & Chapman (1961)
Pateint A : "I can't shut things out"
Patient B : "I let all the sounds come in that are there"
Patient C : "I'm attending to everything at once, so I don't
really attend to anything"
These may be indicative of deficits in sensory gating
(e.g. selective attention).
Psychology and neuroscience
PS1009
• Understanding the neural and neurochemical basis of
psychological function in the normal brain
• Perception
• Intrinsic processing
• Motor output
• ‘Behaviour’
• Studying the neural and neurochemical basis of behaviour gives
us insights into dysfunctions underlying psychiatric disease.