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How the Brain Works
Scanning the Brain:
PET (Positron Emission Tomography)
SPECT (Single Proton Emission Computerised Tomography)
Both of these are nuclear medicine studies, utilizing small doses of radioactive isotopes to study cerebral patterns. Unlike CT, MRI and EEG which study anatomical structures, PET and SPECT can give information on the activity and metabolism of the brain. SPECT utilizes CERETEC ( a radio pharmaceutical) which can give the images of cerebral functions. PET and SPECT scans, because they give a picture of the functioning of certain parts of the brain, can be useful in psychiatric diagnoses before and after treatment. Here are some of the general findings from these scans of the possible functioning of different parts of the brain.
Prefrontal Cortex
This area is involved with attention span, perseverance, judgement impulse control, learning from experience, problem solving and is connected with the limbic system ( a term used to describe the areas of the midbrain particularly involved in emotional states). Problems that can arise: short attention span, distractibility, poor impulse control, poor judgement and difficulty learning from experience.
Temporal Lobe (dominant).
Left temporal lobe is usually dominant and is involved in understanding and processing language, intermediate and long term memory storage, visual and auditory processing, emotional stability. Problems that can arise with poor functioning are issues with aggression, dark and violent thoughts, reading difficulties, emotional instability.
Temporal Lobe (non-dominant)
Right temporal lobe is usually non dominant and is involved in recognizing facial expressions, registering tonal information, rhythm and visual learning. Problems that can arise are difficulties in facial and vocal recognition and in general difficulties with social skills.
When both temporal lobes are dysfunctional problems that can arise are problems with memory, headaches, abdominal pain, abnormal sensory perceptions, déjà vu, periods of confusion, intense religious and moral preoccupations. There can be seizures i.e. temporal lobe epilepsy. Since the temporal lobes are seen as a storehouse of memories they are often involved in flashback memories triggered by smell, taste, visual, auditory and tactile stimuli.
Cingulate Gyrus
Allows for cognitive flexibility, moving from idea to idea, emotional adaptability, making choices. Problems that can arise are excessive worrying, obsessions (stuck on thoughts),compulsions (stuck on behaviors), oppositional, argumentative and uncooperative tendencies, addictive behaviors, cognitive inflexibility, eating disorders, road rage.
Basal Ganglia
Functions of these ganglia are to do with coordination between feeling and movement, modulates unwanted motor behaviors, enhances motivation emotional equilibrium. It is also seen as part of the midbrain that is concerned with the experience of ecstasy It also includes the nucleus accumbens which is associated with musical appreciation. Problems that can arise with dysfunction; anxiety, nervousness, panic attacks, conflict avoidance, low motivation, pessimistic attitude, tics, headaches.
Hippocampus
This part of the brain is closely associated with the temporal lobes. One of its functions is to process new memories, remembering recent details and transferring information into memory. It is also connected with learning new skills, e.g., playing tennis, or earning to play a musical instrument. Alzheimer’s disease affects the hippocampus before other parts of the cortex.
Amygdala
This part of the brain is essentially associated with processing input from the visual, auditory and somatosensory cortices in order to recognise elements that signal danger. It is part of the "fight or flight" mechanism and when stimulated creates significant levels of fear and/or aggression.
