Social Cognition and Mental Health

Neuroplasticity

• 3 months of intense juggling practice

• Modest increase in intraparietal sulcus

• Reduces once practice stops

Anatomical plasticity in healthy adults

Intense practice, or extremes of behaviour, may produce visible structural changes in anatomy

• Changes in size

• Increase density

• Very small effects

Limited evidence in most of the general population

• E.g., limited/no correlation between hippocampus size and spatial ability in random sample of the population

Neurogenesis

Adult neurogenesis is limited to ~3 regions

Subventricular zone (our wall of ventricles)

• Neurons migrate to olfactory hub

• May be redirected elsewhere following brain injury

Dentate gyrus of Hippocampus

• ~700 neurons per day

• Rate decreases with age

Neurogenic hypothesis of Depression

• Evidence of reduced hippocampal volume in depression

• Neurogenesis is reduced in depression

• Neurogenesis is inhibited by stress

• Fluoxetine treats anxiety and depression

• Neurogenesis is stimulated by fluoxetine

Takes days-weeks to develop

• Neurogenesis in dentate gyrus seems more important than subventricular zone

Major depressive disorder

• 350 million people worldwide

• Variety of symptoms related to mood

• ‘Diminished ability to think or concentrate, or indecisiveness nearly very day’

• Cognitive symptoms
  Executive function, attention, memory, processing speed, psychomotor skills

• During both symptomatic and remitted phases

Exercise, Cognition and Depression

• Short bursts of intense activity improve test performance

• Long-term improvements in cognition with exercise

  Especially pronounced in ageing

• Exercise relives symptoms of depression

  More effective for mood symptoms than for cognitive symptoms

  Effective as a treatment

• Exercise reduced stress and anxiety

• Effects on HPA axis may drive reduced anxiety and depression

Social Cognition

Social Orienting

• Joint attention

• Considering another’s intentions

• Responding appropriately to others

• Taking turns

Language - Cognition

• Idioms

• Symbolic play

• Non-verbal cues

• Other executive function/planning/language

Theory of mind

• Ability to attribute mental states (understands that other have beliefs, desires, intentions, perspectives that are different from one’s own)

• Ability to attribute mental states

  Autism - ‘mind blindness’ (Simon Baron-Cohen 1985)

• Normally develop theory of mind age 3-4

Delayed in autism

Brain regions involved in theory of mind

• Medial prefrontal cortex

• Temporal-parietal junction (TPJ)

• Posterior superior temporal sulcus (pSTS)

• Posterior cingulate cortex (PCC)

• Precuneus

Medial Parietal Cortex

Autism Spectrum Disorders

• Large (10x) increase in diagnoses in the last 10-15 years

In some countries (Korea = 1 in 52, Iran = 1 in 1600)

• 4:1 male:female

• Some genetic component

• No approved drugs

• Spectrum

Many of us have some autistic traits

Neurodiversity

Autism Spectrum Disorders DSM-V

Persistent deficits in social communication and social interaction across multiple contexts (need all 3)

• Social-emotional reciprocity

• Non-verbal communication

• Developing, maintaining, and understanding relationships

Two of:

• Restricted, repetitive patterns of behaviour, interests, or activities

• Insistence on sameness, inflexible adherence to routines

• Highly restricted, fixated interests that are abnormal in intensity or focus

• Hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the environment

Common behaviours in ASD

• Insistence on sameness

• Repetitive movements - spinning in a circle - fidget spinner

• Not responsive to verbal cues or eye contact

• Difficulty in social situations

E.g., idioms

Difficulty expressing needs

Deficiencies in symbolic thinking

Attachment to objects (rather than people)

Self-injurious behaviours

Echolalia

Intellectual disability (70%)

Level of ASD impairment

Level 3 - Requiring very substantial support

Level 2 - Requiring substantial support

Level 1 - Requiring support

Level 0 - No support

Autistic spectrum disorders

Asperger’s Syndrome

• Symptoms are less severe

• No language delay

• No clinically significant cognitive delay

Pervasive developmental disorder - not otherwise specified (PDD-NOS)

Autism symptoms but not sufficient to meet full autism diagnosis

• Almost all of us have some autistic traits

Empathy

The ability to sense, understand and share other people’s emotions

Two main types of empathy

Cognitive empathy

• Reading body language or facial expressions

• Imagining what other people are feeling

• Impairment in autism

• Not impaired (better?) in antisocial personality disorder + psychopaths

Affective empathy (or emotional empathy)

• Appropriate emotional response to what someone else is feeling

• Caring about how other people feel

• Not impaired in autism

• Impairment in Antisocial Personality Disorder and Psychopaths

Systemising

• Understanding, predicting and constructing rule-based systems

• Objects (rather than people)

• Pattern recognition

• ‘Opposite’ to empathising

Neurodiversity

Autism is ‘hyper systematising’

• Important and valuable for society

Autistic people better at recognising sounds

• Pattern recognition

Anything involving systems, patterns and repetition

Brain size in autism

• Starts off slightly larger (ages 3-10)

• Ends up slightly smaller in adulthood

• Differences mostly in frontal + temporal lobe

  Cortical thickness

• Amygdala - may be enlarged

Data is inconclusive

Cerebellum + ASD

• Reduced cerebellar size and number of cells in autism

• Meaning is unclear

Some evidence of motor symptoms in autism

More likely indicates unknown/poorly understood roles of cerebellum in behaviour

Role of the cerebellum

Co-ordination of movement

• Not initiation

• Not selection

Motor learning

Motor predictions

Narrowing range of motor options

Ataxia

Wide gate, instability of trunk

Dysmetria

Inability to co-ordinate complex motor activity involving several muscle groups

Dysdiadochokinesia

Inability to perform co-ordinated smooth rapid alternating movements of the hands

Cerebellar cognitive affective syndrome

Patients with cerebellar damage may show cognitive deficits

• Less pronounced than motor

• Cerebellum heavily connected to cortex

Deficits in

• Executive function, linguistic processing, spatial cognition, and affect regulation, personality change

Cerebellar damage associated with development of autism- like symptoms

Dysmetria of thought

Cerebellum optimises performance by modulating behaviour around a homeostatic baseline, automatically, implicitly, and according to context

• Motor

• Emotional

• Cognitive

• Moderates and co-ordinates, does not generate

• Made predictions about immediate future

Attention to faces in autism spectrum disorder

• Reduced attention to faces

• Reduced activity in fusiform face area when viewing faces

• Slower processing of faces

Also seen in follow-ups with parents and siblings

• More likely to focus on mouth (rather than eyes) and peripheral cues