Cognitive Neuropsychiatry

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Cognitive Neuropsychiatry

• Descriptive psychopathology
• Phenomena
• Normality of psychopathology
• Schizophrenia
• Obsessive-Compulsive Disorder
• Brain imaging

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Descriptive psychopathology

• Classification of mental disorders relies on a
  syndrome approach (e.g. DSMIV).
• Syndromes
• cluster of co-occurring symptoms assumed to have
  the same underlying cause.
• Creates a group norm
• useful for finding out whether drugs affect a
  particular symptom/genetic aetiology.
• Syndrome approach does not always reveal
  psychological processes in the disorder.

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Cognitive neuropsychiatry

• Aims to understand the impairments to cognitive
  processing in individual cases of psychopathology
  using a cognitive model of the normal cognitive
  processing system.
• Focuses on phenomenology of delusions and
  hallucinations rather than the biological or
  chemical causes of psychopathology.
• NB these are not mutually exclusive.

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Reduplicative misidentifications

• Defined by the occurrence of doubles, duplicates
  and substitutes.
• in psychiatric and neurological disorders.
• Reduplication of place, person, time, event,
  objects, parts of the body, self.
• Can occur following a range of brain injuries and
  lesion locations (Hudson Grace).
• PET studies
• reduced blood-flow in orbito-frontal areas left
  caudate left medial temporal lobe.

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Varieties of phenomena

• Intermetamorphisis
• Belief that the self has been transformed body
  and soul into another person.
• Fregoli delusion
• Beliefa persecutor has disguised himself as
  someone known to the patient and who is trying to
  harm them.
• Reduplicative paramnesia
• Belief there are two or more places with the same
  identity even though only one exists (e.g. there
  are two hospitals)
• A single person has more than one identity.

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Capgras syndrome

• Belief that a person - a close relative - has
  been replaced by a double.
• can occur for self e.g. reflection of self in the
  mirror is another person who is following me
  around.
• reflections of others correctly identified.
• Externalise changes to self identity
• reflection must be an impostor.
• Persecutory delusions
• attributing current beliefs to external causes
  rather than to changes to self identity.

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Anosagnosia

• Denial of illness (la belle indifference) e.g., a
  paralysed arm becomes an inanimate object that is
  ignored.
• Accompanies right hemisphere damage to the
  parietal (somatosensory) lobe resulting from
  cerebro-vascular disease but can be observed in
  other disorders dementia.
• Patient admits arm does not move but denies
  paralysis.
• Represents patients attempts to understand loss
  of a limb, loss of perceptual experiences, loss
  of self?

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Cotards delusion

• Person believes that they are dead.
• Bonnet (1769) a female patient who after a stroke
  lay as if dead for four days then insisted she be
  placed in a shroud, put in a coffin and buried.
• Strong correlation with depression.
• Represents depressed patients attempts to
  understand negative emotions?
• Depressed people internalise emotions
• I have no feelings, so I must be dead.

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Features of delusions

• Selectivity of replaced item
• e.g. damaged arm or leg
• Coexistence of types
• Feelings of unreality depersonalisation
• Symbolic aspects
• Retrograde amnesia
• Confabulations

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Symptoms of schizophrenia (DSMIV)

• Negative symptoms are an absence of normal
  function including social withdrawal and lack of
  initiative.
• Positive symptoms is the presence of abnormality
  e.g. hallucinations voices and delusions I am
  Christ.
• Disorganisation refers to bizarre behaviour such
  as odd verbal communication.

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Wisconsin Card Sorting Task (WCST)
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Positive symptoms in schizophrenia

• Frith (1992) suggested that positive (Type 1)
  symptoms are due to the disordered functional
  connectivity between frontal cortex and rest of
  brain (fronto-striatal connections).
• Normal subjects show an inverse correlation
  between activation in the prefrontal cortex and
  temporal cortex on word generation tasks whereas
  patients with schizophrenia show same activity in
  both regions (Friston Frith, 1995).
• Twin data found smaller left temporal lobe and
  hippocampus in affected twin (Davison Neale).

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Hallucinations

• False perception or false beliefs?
• Reality monitoring (Frith, 1992).
• humans have an ability to distinguish between
  sensory inputs that are self- generated actions
  and those that result from external events.
• this allows us to monitor ongoing events.
• internally derived stimuli (voices) attributed to
  an external event as a result of a failure to a
  self-monitoring mechanism (in speech module).

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Cahill and Frith (1996)

• Used self generated speech patterns recorded
  through a throat microphone.
• Schizophrenic subjects more often attributed own
  speech to other speakers.
• Suggests a disconnection between action that is
  internally and externally generated.
• Hallucinations are best understood by locating
  the overt phenomena of voices at a stage of
  speech perception monitoring.

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Maintaining mental states

• Psychotic symptoms result from failure to
  maintain own or others mental states (Frith).
• This meta-cognitive ability has been referred to
  as theory of mind or mentalising ability.
• Cannot reflect beliefs as representations of
  reality so distinction between subjectivity and
  objectivity collapses, leading to the maintenance
  of delusional states cannot represent intention
  of own actions.
• Actions experienced without accompanying sense of
  self generation -gt to delusion of alien control.

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Schizotypy and mentalising

• Schizophrenic patients find it difficult to infer
  intentions behind ambiguous speech and fail on
  formal tests of theory of mind.
• Biological relatives also (Corcoran, 1996).
• Langdon and Coltheart (1999) normal subjects
  show defective mentalising ability.
• Non-clinical undergraduates with predisposition
  towards Sz who were high on a schizotypy scale
  (SPQ scale Raine, 1991).

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Self awareness

• Knowing oneself as an identity and ability to
  monitor own mental states (and others).
• Vogeley, Kurthen, Falkai and Maier (1999) suggest
  agency awareness follows
• feedback from self monitoring (parietal).
• body centered perspectivity (parietal).
• personal identity over time called Unity.
• self perception (pre-frontal cortex)
• schizophreniadysfunction of self monitoring.

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N200
P300
Michie, P.T., Innes-Brown, H., Todd, J.
Jablensky, A.V. (in press) Duration MMN in
biological relatives of patients with
schizophrenia spectrum disorders. Biological
Psychiatry Michie, P.T. What has MMN revealed
about the auditory system in schizophrenia?
International Journal of Psychophysiology, 2001,
42, 83-100.
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The Who system

• Comprehending anothers intentions and actions is
  a result of shared activation between perceived
  actions and actions generated by the self
  (parietal/frontal).
• Attribution of action to self results from
  co-activation between perception and
  somoto-sensory feedback (Jackson Decety, 04).
• Geogieff and Jeannerod (1999) studied intentions
  to act and self generated action and found same
  areas activated in DLFC.

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Cognitive neuropsychology

• Aim to study and understand impairments to
  cognitive processing in cases of brain damaged
  patients using a model of the normal cognitive
  processing system (memory, language, object
  recognition).
• Concentrates on empirical data that either
  supports or disconfirms a theoretical view about
  the form and/or the organisation of a specific
  mental function.
• Was a reaction to the development of syndromes in
  aphasia e.g., Brocas aphasia that did not
  capture the individual differences among
  patients.
• Studying individuals false beliefs can tell us
  about the process of normal belief functioning

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Summary

• Cognition is more than vision, memory and
  language and involves beliefs, reasoning,
  inference making and our sense of self.
• These phenomena can be studied using the
  principles of cognitive neuropsychology.
• This may lead to the development of models of
  belief processing as well as new paradigms for
  studying brain activation in belief tasks.

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Further readings

• Breen, N., Caine, D., Coltheart, M, et al.
  (2000). Towards an understanding of delusions of
  misidentification Four case studies. Mind and
  Language, 15(1), 74-110.
• Davies, M., Coltheart, M. (2000). Introduction
  Pathologies of belief. Mind and Language, 15(1),
  1-46.
• Halligan, P.W. David, A.S. (2001) Cognitive
  neuropsychiatry towards a scientific
  psychopathology. Nature Neuroscience, 2(3),
  209-215.
• Halligan, P., Marshall, J. (Eds.) Method in
  Madness, Psychology Press, Hove, 1998.
• Langdon, R. Coltheart, M. (1999). Mentalising,
  schizotypy and schizophrenia. Cognition, 71,
  43-71.
• Langdon, R., Coltheart, M. (2000). The
  cognitive neuropsychology of delusions. Mind and
  Language, 15(1), 184-218.
• Tallis, F. (1997) The neuropsychology of
  obsessive-compulsive disorder A review and
  consideration of clinical implications. British
  Journal of Clinical Psychology, 36, 3-20.
• Thompson, PM et al (2001) Mapping adolescent
  brain change reveals dynamic wave of accelerated
  gray matter loss in very early-onset
  schizophrenia. Proceedings of the National
  Academy of Sciences, 98, 11650-11655.

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Obsessive-Compulsive Disorder

• Evolutionary advantage of repetitive behaviour
  e.g., birds building a nest.
• Inhibition of motor behaviours (Martinot et al.,
  1990 Enright Beech, 1990, 1993).
• Visual attention deficits (Nelson et al., 1993).
• Deficit to action system?
• Memory impairment?
• Visuo-spatial scratch pad impairment?

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Evidence for frontal lobe impairments

• Fronto-striatal biological basis
• OCD patients show more activity in caudate nuclei
  and orbital gyri during brain imaging (Tallis,
  1997).
• Patients with OCD perform worse on tests of
  frontal functioning particularly set shifting
  tests e.g., Wisconsin Card Sorting Test, verbal
  fluency.
• Serotonin reduces OCD behaviours and this
  neurotransitter is known to affect the
  fronto-striatal pathways in the brain.

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Categorical approach to diagnosis

• Polytypic approach characterised by many typical
  individuals of a particular class being grouped
  together based on a minimum number of criteria.
• This results in many heterogeneous groups that
  may not be able to accommodate specific phenomena
  e.g., the content of delusions (the Capgras,
  Cotard and Fregoli delusions).
• Makes it difficult to find the normal counterpart
  to abnormal behaviour.
• What normal behaviour corresponds to the defining
  features of schizophrenia?

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Cognitive neuropsychology

• Neuropsychological dissociations in brain damaged
  patients reflect different parts, modules or
  mechanisms of the normal information processing
  system e.g., reading words aloud and reading
  nonwords aloud.
• Explanations do not depend upon neuroanatomical
  constraints but they may result in
  neuroanatomical models.
• Highlights the relative normality of
  abnormality e.g. anomia versus word finding
  difficulties.
• Emphasises symptoms rather than syndromes e.g.
  poor object naming.

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Cognitive neuropsychiatry

• Psychiatric dissociations reflect different parts
  or mechanisms of the cognitive system e.g.,
  inferential reasoning versus delusional beliefs.
• All men die, I am a man, therefore I am dead
  (Cotards delusion).
• Does not depend on a neuroanatomical explanation
  but can lead to one.
• Highlights the normality of abnormality e.g.,
  false beliefs
• Stresses symptoms rather than syndromes e.g., a
  delusions continuum
• Delusions represent abnormal belief fixation
  whereas hallucinations represent faulty self
  monitoring.

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Phenomena studied in cognitive neuropsychiatry

• Mind blindness (Baron-Cohen, 1988).
• Delusional misidentification syndromes (Young, et
  al., 1993).
• Thought echo (David, 1994b).
• Self monitoring ability (Frith, 1993).
• Mentalising ability in non-psychiatric, high risk
  subjects (Langdon Coltheart, 1999).
• Obsessive compulsive disorder (Tallis, 1997).
• Alien control (Frith and Done, 1989).

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Depersonalisation phenomena

• Temporal reduplication
• déjà vu experience where an ongoing event or
  period of time has also occurred in the past.
• Reduplication of objects
• usually things that belong to the patient
• Body parts
• body parts have been added or replaced e.g.,
  phantom organs such as arms legs eyes and ears
  self is intact.
• Self
• the self has been replaced.

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Autism theory of mind

• Coltheart (1999) TICS
• Syndrome or symptom?
• There are many associated symptoms that correlate
  with each other in normal development
• Should not think of it as a syndrome of related
  disorders.

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Alien Hand (Parkin, 1996)

• Two selves in the one brain?
• There is a belief that one hand is out of own
  control or in extreme form the hand does not
  belong to the patient.
• Involves involuntary, compulsive use of
  utilitarian articles placed within the patients
  reach ie. Utilisation behaviour
• Motor perseveration (e.g., tapping).

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• Inter-manual conflict the left hand tries to stop
  what the right hand is doing or vice versa. A
  dissociation between the goals of the left and
  the right hands.
• Results from lesions to the medial frontal cortex
  and/or the genu of the corpus callosum with
  involvement of the supplementary motor area.
• There is depersonalisation from the actions of
  the alien hand such that patients may refer to
  the limb as it or the baby and give it a name.

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• Usually occurs with actions that require movement
  of only one hand
• i.e. opening and closing doors pulling up and
  pulling down.
• May also occur in tasks where there are a number
  of components required.
• Role of consciousness. Limb operates outside of
  awareness but also has intention (usually
  malevolent).

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• Hudson A.J., Grace G.M. (2000). Misidentification
  syndromes related to face specific area in the
  fusiform gyrus. Journal of Neurology, PS 69(5),
  645-648.

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• Blakemore et al (1998)
• PET scans of normal subjects during self
  monitoring of sensory events that were externally
  generated or a consequence of self generated
  actions.
• Found increased activation self monitoring in the
  medial posterior cingulate cortex the left
  insula dorsomedial thalamus and superior
  colliculus (sub-cortical structures).

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• Mentalising was tested with false belief picture
  sequencing task similar to the one used with
  autistic children (Leslie and Frith,1988).
• They found highly schizoptypal but
  non-psychiatric subjects were worse on
  mentalising tasks.
• They also found that poor mentalisers had more
  psychotic like traits e.g., asociality.
• Not due to an executive planning deficit nor
  failure to inhibit cognitively salient
  inappropriate information.
• A specific cognitive module that is dedicated to
  inferring and representing mental states that
  when dysfunctional, causes psychotic like states.
• Supports the idea that there is a specific
  problem with mentalising ability in people who
  are on the spectrum for schizophrenia including
  non-patients.

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• Note that not all subjects who were high in
  schizotypy performed poorly on the test and also
  the effect was not very large in the non-patient
  sample.
• The results do highlight the normality of
  abnormality and the fact that psychotic traits
  are on a continuum.
• Shows that there is a disorder to the normal
  information processing system that may result in
  psychosis.

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• Anxiety as a mediating variable.
• McGuire et al (1994) using PET found that symptom
  intensity for OCD patients was increased in
  anxiety related conditions with increased blood
  flow to the inferior frontal gyrus and several
  basal ganglia structures.
• Implications for treatment increase the
  distinctiveness of behaviour using imagery to
  enhance poor memory?

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Braver, Barch Cohen (1999)

• Hallucinations are perceived actions without an
  agent resulting from a disconnection between
  knowledge of own intentions and perceived actions
  of another.
• Cognitive deficits in schizophrenia result from a
  failure to exert control over thoughts and
  actions reflecting an inability to update and
  maintain internal representations of events.
• Thompson-Schill (2003)

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Memory impairments?

• Situation specific checking result of information
  processing deficits in visuo-spatial memory.
• OCD patients have memory impairments especially
  memory for actions (Tallis, 1997).
• Doubt relating to past actions.
• Visuo-spatial deficits associated with basal
  ganglia lesions also Parkinsons and Tourettes
  patients.
• If specificity of checking is due to a memory
  problem then you might expect a broad range of
  checking behaviour (i.e., not just light
  switches).
• Patients know that a light switch is off yet
  still engage in checking behaviour.