Recognising the self Flashcards
What is an auditory hallucination and what are some of the facts surrounding it?
Perceptions in the absence of external stimuli.
60-70% people with schizophrenia
25% of those with it will attempt suicide
30% TR
What are the two models of AH?
One: like epilepsy, continual firing
Two: thoughts are words, so AH is the inability to tag those words are your own
How can we compare the competing models of AH?
Neuroimaging:
1: What areas are involved in AH
2: What structures are responsible for narrative thought
3: Compare these areas
What phenomena does the MRI in AH take advantage of?
The delay in brain activity.
What areas did the MRI scan of AH show as significant?
Auditory cortex and inferior frontal gyrus (Brocas area)
What area is significantly different in AH patients?
Superior temporal gyrus: Speech monitoring
Motor Movements: Cerebellum
Novel word detection: Parahippocampal gyrus
What major difference is shown in the superior temporal gyrus between AH and controls?
Listening is not turned fully off by AH patients.
What does diffusion tensor imaging show us?
That white matter tracks between Brocas and Wernickes area are pronounced in those with AH.
The Superior Longitudinal Fasiculus.
How do we demarcate perceptual actions from our own and those of others?
Via predictive or forward models.
How was the Physiological model tested?
Using a lever using just a direct finger push or using a joystick.
Healthy controls and Schizophrenics are accurate with joystick.
Healthy controls 30% more pressure with direct force. Schizophrenics far less so.
The somatosensory area of the brain attenuates less in Schizophrenia, measured by delayed pressure (250ms), making it difficult to know if the actions and thoughts are their own.
What are the two top ways in which people with AH cope with their condition? And which strategies have been developed as a result?
Talking to others and listening to something of interest.
Transcranial magnetic stimulation and transcranial direct stimulation.
Briefly describe TMS.
A figure 8 conducts a magnetic field at right angles.
Slow TMS (1Hz) will reduce cortical excitation while Fast TMS will increase it.
Can be areas connected too.
Effect can last hours and weeks.
What did the experiment looking at stimulation of the right temporal parietal junction find?
That slow stimulation using TMS reduced activity, but the opposite side showed an increase. Therefore compensatory response via white matter tracks.
What is Trans Direct cranial stimulation?
A node is inserted close to the area of intended stimulation.
Is tDCS effective and if so in which areas where?
Yes, it has been shown to decrease stimulation in areas like wernickes and brocas area.
