Low mood - thoughts and feelings Flashcards
How to explore the brain?
- genetic studies eg. twin studies, rare variants, genome wide
- cellular level eg. synaptic function, optogenetics
- neuroimaging eg. structural, tractography, functional inc. fMRI
Developing ideas about the brain?
- mind body dualism
- localisation
- Phineas Gage
- Impact of cerebrovascular events
- wilder penfield - role of neurotransmitters
- neural circuits and functional connectivity
What concepts relate to brain function?
- default mode network
- auditory network
- medial and lateral visual network
- sensorimotor network
- praecuneus network
- dorsal visual stream
- basal ganglia network
- executive control network
- visuospatial network
Depression aetiology?
- HPA axis changes
- functional connectivity changes
- monoamine hypothesis
- genetics and epigenetics
- structural brain changes
- neuroplasticity and neurogenetics
- inflammation
What are thoughts and feelings?
- intimately tied up with how we understand ourselves as humans and what it is to be conscious
- conscious manifestations of underlying neural processes
What are thoughts?
conscious counterpart to cognition (neural computations)
What are feelings?
conscious counterpart to emotional states (Driven by underlying neurophysiological states)
What is cognitive behavioural therapy based on?
recognising unhelpful patterns of thoughts, feelings and behaviours and learning new ways to address these
How to classify emotion?
- set of basic emotions (4-12)
- 2 axis system known as core affect (hedonic/arousal)
What things increase survival? What things decrease survival?
- induce positive emotions = improve survival
- negative emotions = worsen survival
What are mirror neurons?
- function debated
- role in social interaction, social learning, motor mimicry
How is emotion learnt?
learnt through reciprocal interaction
What area of the brain do thoughts and feelings take place?
-highly folded neocortex (pre-frontal cortex)
-emotions = amygdala and prefrontal cortex
(limbic system)
What area of the brain is responsible for fear and desire?
- amygdala
- ventral striatum
What are the neuron types in each region?
- excitatory neurons (glutamate)
- inhibitory neurons (GABA)
What are synapses modulated by?
various other neurotransmitters eg. 5-HT, NA, DA
eg. most antidepressants act via modulation of these neurotransmitters
What does the pre frontal cortex integrate?
- processed sensory info (sensory cortices)
- memory (hippocampus)
- emotion (amygdala)
- behavioural drives (ventral striatum)
How does the amygdala act as an emotion generator?
passing sensory info about the world (perceptions) and our internal states (interoception) to create the neural substrate of emotions
How does the PFC act as an emotion regulator?
- can override emotions generated by the amygdala when appropriate
eg. remaining under rational conscious control
Function of hippocampus?
memory
Function of sensory cortex?
perception
Function of hypothalamus?
systemic response
Function of motor cortex?
behavioural
What is learning?
the way in which our neural representations are updated
eg. motor, sensory, emotions
How does learning occur?
through neurons firing in temporal association
“cells that fire together wire together”
What is the Bayesian brain model?
describes brain as hierarchical system of statistical inference consisting of:
- top down prediction from higher integrative centres eg. PFC
- bottom up evidence generated through perceptual and other cognitive processes eg. sensory cortex, hippocampus, amygdala
When is an error signal produced in a Bayesian brain system?
if the sensory data we receive differs from our predictions
What is key for memory consolidation?
sleep
Process of memory?
- attention
- registration
- short term memory
- long term memory
- consolidation
What is memory recall and storage biased by?
our emotional state
-prior beliefs and behavioural patterns to adapt in based on previous experiences
What is pyschosis?
people lose some contact with reality
- perception
- stimuli salience
- executive function
What are some symptoms of psychosis?
-hallucinations
-delusions
(core positive symptoms)
-executive dysfunction
(negative symptoms)
What is perception?
the way in stimuli received across sensory modalities are processed in order to create neural representations that in turn drive further cognitive and neural processes
What are perceptions based upon?
- sparse sensory info we have about the world
- prior knowledge
- integration across sensory modalities
What do schizophrenic patients show on an EEG?
- reduction or loss of the normal EEG response to a stimuli at 300ms
- P300 signal is involved in evaluation of sensory input
What is attention?
- provides a means of filtering the sensory info we are bombarded with
- either under conscious (value driven, top down)
- or unconscious control (stimuli driven, bottom up)
What is attention necessary for?
to respond to or store sensory info
What is a common feature of schizophrenia?
impairment of executive functions (mostly localised in prefrontal cortex)
-extent of impairment correlates with functional outcomes
Function of dorsolateral PF region?
- working memory (rememebr number)
- reasoning (similarity between objects)
Function of ventromedial PF region?
- motivation (enjoy activities they used to)
- social skills (follow social rules)
Function of medial PF region?
- attention (irrelevant sounds distract)
- predictive planning (routine activity)
What is dysconnectivity?
abnormal relationships between neurons at multiple scales of space and time
