University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

318

Pages:

3
Author:

Mariam A.

Tools of mental health neuroscience    Functional measures: o Electrodermal activity (skin conductance). o EEGs. Structural measures: o MRI. Both: o fMRI. Electrodermal activity (EDA)  Intense emotions are often accompanied by tendency to sweat.  Sweat glands can also be activated by mild emotions or various cognitive tasks.  EDA is recorded as a change in electrical resistance following passage of an external small current across the skin. EEG  Recording of brain wave electrical activity from the surface of the scalp.  Greater contribution to EEGs from cortical structures, rather than deep structures such as the amygdala.  Frequency of EEG signal can range from very slow activity (<1 Hz) to very fast rhythm (>80 Hz).  Following recording analysis (FFT) provides details on EEG bands. MRI    Used to produce structural images of soft tissue (e.g. brain). Image arises because of the interaction between the applied magnetic field of the imaging magnet and the intrinsic magnetic properties of the nuclei. Commonly used clinical assessment of neurological disorders over past two decades, its use in psychiatry is on the rise. fMRI  Uses that fact that increases in neuronal activity are associated with increased local cerebral blood flow and cerebral blood volume, and decreases in local [deoxyhaemoglobin].  First reported study using fMRI involved a visual paradigm in 1991.  To detect statistically significant changes, many sequential images are taken during which subject alternates between performing “on” and “off” tasks. Brain regions   Limbic system is responsible for our emotional life and formation of memories. Suspected to be responsible for development of mental health disorders. Mood disorders       Prevalence in Australia is 3.4% in males and 6.8% in females. Organised into 4 categories. Mood episodes: o Major depressive episodes. o Manic episode. Depressive disorders: o Major depressive disorder. o Dysthmic disorder. Bipolar disorders: o Bipolar I disorder. o Bipolar II disorder. Other mood disorders: o Substance-induced mood disorders. o Mood disorders due to general medical condition. Major depressive disorder  Symptoms: o Depressed mood most of the day.   o Loss of interest or pleasure (in all or most activities, most of the day). o Large increases or decreases in appetite (significant weight loss or gain). o Insomnia or excessive sleeping (hypersomnia). o Restlessness (psychomotor agitation) or slowness of movement (psychomotor retardation). o Fatigue or loss of energy. o Feeling of worthlessness or excessive or inappropriate guilt. o Diminished ability to concentrate or indecisiveness. o Recurrent thoughts of death or suicide. Brain regions implicated: o Prefrontal cortex, specifically orbitofrontal cortex, and anterior cingulate. o Amygdala. fMRI shows amygdala activation during the experience of sad mood in young girls at risk of developing depression.