Cortical abnormalities

Goldstein, J. M., Goodman, J. M., Seidman, L. J., et al. (1999) Cortical abnormalities in schizophrenia identified by structural magnetic resonance imaging. Arch. Gen. Psychiatry. 56, 537-547. 

Gorski J, Jones KR, Sretavan D, Reichardt LF. FAK deficiency 98. in cells contributing to the basal lamina results in cortical abnormalities resembling congenital muscular dystrophies. Neuron 2003 40 501-514. 99. 

Many seizures are associated with distinctive EEG patterns (Fig. 16.1). Perhaps the most striking is the 3 per second spike wave activity seen in most leads (cortical areas) in absence seizures, which can be invoked by hyperventilation. Otherwise distinctive EEG patterns are usually only found during an actual seizure, with burst spiking seen alongside clonus in TCS and abnormal discharges with the behavioural patterns of partial epilepsy and in particular that originating in the temporal lobe. 

If the change in cortical electrical characteristics is permanent, why don t seizures occur all the time This is probably because the occurrence of an individual seizure depends upon an interplay of environmental and internal brain factors which from time to time result in loss of the normal mechanisms that contain and control abnormal neuronal firing. Some common factors are sleep loss and fatigue, but it is impossible to determine what sets off a particular seizure in most patients. 

Functional neuroimaging studies suggest that frontal and occipital brain areas are integral to the anxiety response. Patients with panic disorder may have abnormal activation of the parahippocampal region and prefrontal cortex at rest. Panic anxiety is associated with activation of brain stem and basal ganglia regions. GAD patients have an abnormal increase in cortical... 

Seizures Clinical or subclinical disturbances of cortical function due to a sudden, abnormal, excessive, and disorganized discharge of brain cells. Clinical manifestations include abnormal motor, sensory and psychic phenomena. Recurrent seizures are usually referred to as epilepsy or "seizure disorder." [NIH]... 

The role of serotonin (5-hydroxytryptamine, 5-HT) has also been extensively studied in depressed patients. Whereas the overall psycho-physiological effects of noradrenaline in the CNS appear to be linked to drive and motivation, 5-HT is primarily involved in the expression of mood. It is not surprising therefore to find that the serotonergic system is abnormal in depression. This is indicated by a reduction in the main 5-HT metabolite, 5-hydroxy indole acetic acid (5-HIAA), in the cerebrospinal fluid of severely depressed patients and a reduction in 5-HT and 5-HIAA in the limbic regions of the brain of suicide victims. The 5-HT receptor function also appears to be abnormal in depression. This is indicated by an increase in the density of cortical 5-HT2a receptors in the brains of suicide victims and also on the platelet membrane of depressed patients. Platelets may be considered as accessible models of the nerve terminal. 

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