Mental Disorders - Psychological Interventions Flashcards
What is plasticity?
The ability of the brain to change
- changes in the brain = changes in our abilities
- gray matter thickening or shrinking
- neural connections being forged and refined or weakened and severed
Brain and plasticity
The brain - a highly plastic organ
- previously - thought to be quite static
- actually - there is a lot of rapid on-going changes
- certain windows for plasticity
- e.g. childhood and language learning
- has important implications for therapeutic approaches
Sperry - Brain Plasticity
Split brain patients
- fully severed corpus callosum connection between two hemispheres
- P’s were still able to complete tasks etc
Argue that there is some form of brain plasticity going on here?
Brain Plasticity and learning things
Draganski et al (2004)
Juggling training
- whole brain magnetic resonance imaging
- visualised learning-induced plasticity in brains
- transient and selective structural changes in brain areas that are associated with the processing and storage of complex visual motion
Changes in gray matter
- even after the training stopped - there was still an increase in volume
Behaviour training - direct / immediate correlate
Brain Plasticity and learning things
Maguire (2000)
London taxi cab drivers
Learning the ‘knowledge’
DV - volume of the hippocampi - anterior, body & posterior regions
Taxi drivers - significantly increases GM volume in the L and R posterior hippocampi compared to controls
Learning something - the ‘Knowledge’ etc - has an impact on your brain connections etc???
Brain Plasticity - Nudo et al (2001)
Stroke patients
Stroke / other sources of injury
- looked at the role of adaptive plasticity in recovery of functions after damage to motor cortex - review article!
- stroke / other source of injury to motor cortex often result in movement deficits
- recovery - initially thought to be not very good BUT recent neuroimaging studies have provided substantial evidence that adult cerebral cortex is capable of significant functional plasticity
Found that motor cortex of adult mammals can undergo widespread changes in functional organisation as a result of behavioural experience and central or peripheral injury
New motor skills - alters motor cortex
- muscles and movements get represented over greater cortical territories
- this is accompanied by anatomic alterations (e.g. increase in synaptic numbers)
What is the rationale for conducting neuroimaging research into the effects of psychological interventions?
(1) Investigate the effects they have on brain functioning
(2) Identify the mechanisms of action
(3) Define appropriate biomarkers for treatment selection and response
What is Cognitive Behavioural Therapy (CBT)?
- therapist and client work together as a team to identity and solve problems
- helping clients overcome their difficulties by changing their thinking, behaviour and emotional responses
- effective in more than 1,000 outcome studies
- used for a wide range of psychiatric disorders
- has also been adapted for a wide range of individuals (children, adolescents etc)
CBT and Neuroimaging
- the psychological intervention which has been most closely investigated in Neuroimaging
- there is a sizeable literature as these interventions have lasting and memorable changes on brain functioning
CBT and Neuroimaging
Porto et al (2009)
- does CBT change the brain?
- review of neuroimaging in anxiety disorders
- essentially looking at the neurobiological consequences of psychological treatment
CBT and Neuroimaging
Porto et al (2009) - SPECIFIC PHOBIAS
Spider phobias
- CBT was shown to be effective in reducing symptoms
Before treatment - significant activation in dorsolateral PFC and para-hippocampal gyrus
- after CBT - no significant activation in these structures
CBT reduces phobic avoidance through:
- the extinction of contextual fear which is learned in the hippocampal/parahippocampal region
- reduces the dysfunctional and catastrophic thoughts in the PFC
CBT and Neuroimaging
Porto et al (2009) - SOCIAL PHOBIAS
Looked at a PET study
- significant reduction of regional blood flow bilaterally in amygdala, hippocampus and medial and anterior temporal cortex
- hippocampus and amygdala - structures related to the conditioning of aversive stimuli in P’s with social phobia
- finding this out - implications for future treatments????
Functional Neuroimaging of Anxiety
Etkin & Wager (2007)
Meta-analysis of emotional processing in PTSD, social anxiety disorder and specific phobias
Study of human anxiety disorders - benefitted greatly from functional imaging approaches
BUT individual studies have varied greatly in their findings
Looked at fMRI and PET studies - PTSD, social anxiety disorder, specific phobia and fear conditioning
- looking at neuroimaging results of these disorders
- can find regions of interest / vulnerable areas
- target them for future treatment
- understand how these disorders work
Functional Neuroimaging of Anxiety
Etkin & Wager (2007) - RESULTS
PTSD - hypo- and hyperactivity
Other two - just found hyperactivity
Each disorder had a range of areas demonstrating hyperactivity
- BUT hyperactivity was common in all 3 in 2 structures
- Amygdala and Insula
Amygdala - exaggerated activity in clinical anxiety
- this meta-analysis provided / revealed consistent amygdala hyperactivity in all 3 disorders
- ALSO saw consistent amygdala activation during fear conditioning in healthy subjects
- SO the hyper-activation seen in the 3 disorders reflects a common exaggerated engagement of fear circuitry which results in shared symptoms
What is exposure therapy?
An effusive clinical intervention that is based on progressive confrontation with the pathologically feared stimuli
Approximately 95% of patients treated for phobias in one several hour sessions maintain significant improvements in symptoms for 1 year
Different forms of exposure therapies
Exposure therapy can be placed in different ways
Flooding - expose P’s to the highest rated fear immediately
Systematic Desensitisation - combine exposure with relaxation exercise to make them more manageable and to associate the feared ‘item/object/situation’ with relaxation
Systematic Desensitisation - McGrath et al (1990)
- successful treatment of a 9 year old girl with noise phobia
- used systematic desensitisation
- Lucy - was able to control the presentation of loud noises
- taught relaxation techniques
- constructed a hierarchy of feared noises - gave them scores out of 10
- over the sessions, was able to do more tasks associated with the loud noises
- eg allowing a balloon to be popped, being able to pop the balloon, party poppers, cap gun etc
Problems with Exposure Therapy?
- lots of evidence supporting the efficacy of the treatment
- neuropsychological mechanisms underlying the fear reduction have not yet been discovered
- single sessions present a valuable opportunity
- can identify the immediate changes in neural processing of feared stimuli and then compare them with the LT changes
Exposure Therapy - Hauner et al (2012)
Monitored changes in brain activity ass a result of successful treatment for specific phobia of spiders
Before treatment:
- brain activity for phobogenic vs neutral images was greater in limbic, paralimbic & related regions
- included R amygdala, bilateral insula & cingulate cortex
All P’s treated successfully within 3 hours or less
Treatment involved a progressive series of tasks to approach a live tarantula
Exposure Therapy - Hauner et al (2012)
RESULTS
Increased activity in R dorsolateral PFC in post therapy scan for phobogenic vs neutral images (opposite pattern from baseline)
- involvement emotion regulation?
- result of therapy?
Other areas (initially fear-responsive regions) showed activity decreases
- no longer exhibited activity for phobogenic vs neutral images
- specifically involves areas known to be involved in fear generation
Neurobiology - Depression
Depp. symptoms - depressive mood, negative cognitive biases, behavioural withdrawal
Negative cognitive biases
- negative thinking patterns, memory biases
- these serve to sustain negative emotional processing
Beck - depressed P’s frequently have negative thoughts about themselves
- self-referential bias - this is a key dysfunctional cognition
- maintains and intensifies the depression
Neurobiology - Depression
Disner et al (2011)
Depression
- hyperactivity in amygdala and hippocampus
- correlates with increased activation in subgenual cingulate cortex
- this integrates limbic feedback & relays to the PFC
Activity in subgenual cingulate cortex:
- corresponds with increased activity in medial PFC
- this region shows default mode activity that is associated with internal representations of self
Associations with PFC - emotional regulation
- more focus on negative thoughts etc with depressed P’s
- hyperactivity which is relayed to PFC - more negative thoughts???