Psych 255 unit 7

Neurological

Organic brain/nervous system disorders
E.g., Stroke, Traumatic Brain Injury, Alzheimer's

Psychological/Psychiatric

Disorders of mood, thought, and behaviour
E.g., schizophrenia, depression, anxiety

Causes of Abnormal Behaviour

the causes of neurological disorders are largely known, whereas the causes of psychiatric disorders are less understood.

Brain & behaviour abnormalities result from:

- Genetic errors
- Epigenetic mechanisms (incl. those associated with stress)- Rapid cell death
- Progressive cell death
- Loss of neural connections and functions

The Neurobiology of Abnormal Behaviour

- The complexity of the nervous system makes finding the neural basis of abnormal behaviour extremely difficult
- Abnormal behaviour is not always obviously related to brain damage, and brain damage does not always produce obvious abnormal behaviours

Epidemiology

The study of the distribution and causes of diseases in human populations

A role for Neuroimaging?

- Brain imaging techniques are currently not used to diagnose psychiatric disorders
- In the future, it may be possible to combine behavioural diagnoses and neuroimaging to make diagnoses more objective

Neurological Disorders

- causes largely known
- treatment fairly primitive

Psychiatric disorders

- causes largely unknown and complex
- various treatments that are relatively effective exist

Four main types of treatments

-Neurosurgical
-Pharmacological
-Electrophysiological
-Behavioural

Neurosurgical Treatments (Brain Surgery)

• Very invasive
• Goal is to treat dysfunction by:
- Removing abnormal tissue
- Repairing abnormality
- Damaging dysfunctional area
- Implanting stem cells or electrode

Electroconvulsive Therapy (ECT)

Using electrical stimulation as a treatment for severe depression

Transcranial Magnetic Stimulation (TMS)

magnetic stimulation (alternative to ECT for treating depression)

Common drugs for neurological/behavioural disorders:

- Neuroleptics - schizophrenia
- Anxiolytics - anxiety
- SSRIs - depression
- L-dopa - Parkinson's disease

Behaviour Modification

- Change maladaptive behaviours

Cognitive Therapy

- Change maladaptive thoughts

Neuropsychological Therapy

- Retraining cognitive and behavioural processes lost after injury

Psychotherapy

- Talking about emotional problems gives insight into cause, and helps overcome

Focal Damage

• At coup or contrecoup
• Frontal & temporal especially
• Impairment of specific functions
- Personality
- Social functions

Widespread Damage

• Minute lesions throughout brain
• Loss of complex cognitive functions:
- reduced mental speed
- Poor concentration
- Memory difficulties

Schizophrenia

Diagnostic Symptoms:
- Delusions
- Hallucinations
- Disorganized speech
- Disorganized behaviour or Catatonic behaviour
- Negative symptoms (e.g., blunted affect)

Schizophrenia- neural correlates

• Thin frontal & medial temporal cortices
• Abnormal dendritic fields in dorsolateral prefrontal cortex, hippocampus, and entorhinal cortex
• Abnormalities in dopamine, glutamate, and GABA systems (and serotonin)

Mood Disorders

• Depression
• Bipolar disorder
- Mania and depression

Anxiety Disorders

• Generalized Anxiety Disorder
• Panic Disorder
• Specific Phobias

Imaging studies show increased activity in:
- Cingulate cortex & parahippocampal gyrus at rest
- Amygdala & prefrontal cortex when anxiety provoked

• Benzodiazepines & SSRIs
• Cognitive-Behavioural Therapy

Depression

• Imaging studies show increased activity in:
- orbitofrontal cortex
- Anterior cingulate cortex
- Amygdala

• Antidepressants
- SSRIs (mainly)
• Cognitive-Behavioural Therapy
• Electrophysiological