cognitive and concepts underlying psychiatry

Question 1

sensation

Answer 1

mental process resulting from the ‘immediate external stimulation’ of a sense organ (touch, smell, sight, hearing, taste)

Question 2

perception

Answer 2

ability to become aware/understand something following sensory stimulation (tactile, olfactory, gustatory, visual, auditory)

Question 3

bottom up processing

Answer 3

• Stimulus influences perception – ‘bottom up’
• No preconceived ideas of what you’re looking at
• Brain classically regarded as a device that is purely stimulus driven
• Doesn’t always explain when things go wrong

Question 4

top down processing

Answer 4

• Brain is an active, adaptive system that engages with input from the sensory systems
• Uses background knowledge to influence perception
• Evolutionary advantage – react quicker to perceived threats
• Influenced by perceptual set

Question 5

perceptual set

Answer 5

• The psychological factors that determine how you perceive your environment
• Context
• Culture
• Expectations
• Mood + motivation
Prefrontal cortex: can override old aspects of the CNS – limbic system, executive function

Question 6

illusion

Answer 6

instance of a wrong or misinterpret perception of a sensory experience e.g optical illusion

Question 7

hallucinations

Answer 7

experiences involving the apparent perception of something not present e.g. Schizophrenia, drug induced psychosis (increased dopamine causes ‘positive symptoms’ e.g. hallucinations – treated with antipsychotics – also lots of causes not due to mental illness

Question 8

why do we get hallucinations?

Answer 8

• Top down processing overweighs bottom up signals’ BUT over interpret it causing a sound that’s not there
• E.g. build a model in our minds of what we expect present
Is it always a burden? – depending on patients perceptual set can experience voices as positive or negative
Is management needed? – causing distress, risk to patient or others? – Bio-Psycho-Social approach