the misbehaving brain Flashcards
what are the causes of disordered behaviour
microscopic: - genetic error - huntington diease intermediate - one time events - infections, injuries, toxins Macro level - nutrition, stress
how to identify and classify behavioural disorders
- genetics, brain imaging (MRI PET) stand out
- used to classify disorders and to monitor effectiveness of treatment
- must be sensitive enough to detect unique features of brain disorders and specfiic enough to rule out similar conditions
schizophrenia spectrum
1 in 200 people
- Psychoses are psychological disorders in which a person loses contact with reality, subject to irrational ideas and distorted perceptions.
schizophrenia is characterised by
characterised by negative symptoms • loss of function • emotional withdrawal, flat affect positive symptoms • gain of abnormal state • hallucinations, delusions
Is schizophrenia heritable
- in indentical twins about 50 percent heritable
- schizophrenia beings in utero and is characterised by excessive pruning of short distance cortical connections
can schizophrenia be caused by the environment
- stress (prenatal, adolescence)
- interaction of environmental stress and genetic susceptibility
structural changes in the brain with schizophrenia
- enlarged ventricles in the brain
Frontal lobes: - abnormal activity in dorsolateral prefrontal cortex
Temporal lobes: - Reduced volume of grey matter regions of the temporal lobe
Functional connectivity in the brain when someone has schizophrenia
Functional connectivity between the frontal and temporal lobe disrupted
• these disruptions may contribute to hallucinations
• frontal regions generate speech while temporal regions perceive speech
Neurochemical correlates to schizophrenia
- dopamine
• One of the first neurotransmitters to be implicated in schizophrenia
• High doses of amphetamine -> dopamine -> amphetamine
psychosis that resembles schizophrenia
• reversed with anti-schizophrenia medication
Depression
- most prevelant mood disorder
- unhappy mood
- Loss of interests, energy and appetite
- difficulty concentrating
how depression is dignosed
- based on observable behavioural and psychological features not biological markers
how does someone get depression
• hereditary contributions
• predisposing factors related to brain anatomy and chemistry
• life experiences
• economic or social failure, circadian rhythm disruption, vitamin D and other nutrient deficiencies, pregnancy, brain
injury, diabetes, cardiovascular event, and childhood abuse
functional brain changes that occur with depression
• Increased activation in the frontal lobes (during cognitively demanding
tasks)
• Decreased activity in attention areas (parietal and posterior temporal cortex, anterior cingulate cortex)
- impaired connectivity
- Anterior cingulate detected
errors but not as well correlated with DLPFC
amygdala and depressed patients
Increased activation in the amygdala for depressed vs. controls
• Once amygdala activated it stays activated longer in depressed people vs. controls
• Activity especially heightened during encoding of negative information into
memory
• contribute to persistence of negative memories
ways in which to treat depression
- antidepression
- CBT
- biological treatments
what is CBT
correcting negative thinking and consciously changing behaviours as a way of changing feelings
Altering cortical electrical activity (biological treatments for depression) rTMS
Repetitive transcranial magnetic stimulation (rTMS)
• High frequency rTMS over left dorsolateral prefrontal cortex
• increases activity in this area and the anterior cingulate
regions (Kito et al., 2008)
Symptoms and outcomes of concussions
- Trauma can disrupt the brain’s blood supply, cause bleeding and swelling, expose the brain to infection, and scar the brain tissue.
- Unconsciousness: brief or prolonged (coma)
- Specific impairments may be the result of the coup (site of impact) and/or contrecoup (opposite side) lesion.
- More generalised impairments may be due to widespread damage throughout the brain
Mechanics of TBI
Discrete impairment is most commonly associated with damage to the frontal and temporal lobes, the brain areas most susceptible to TBI.
Symptoms and outcomes of TBI
generally complain of poor concentration or lack of ability.
• they fail to do things as well as they could before the injury, even though their intelligence is unimpaired.
• personality and social behaviour
diagnosis of TBI
• Magnetic Resonance Spectroscopy (MRS) • Modification of MRI • measures biochemical changes in the brain • compares the chemical composition of normal vs abnormal tissue. • promising for accurate diagnosis of traumatic brain injuries.
