Chorea may result specifically from disorders of the basal ganglia, cerebral cortex, thalamus, and cerebellum. The basal ganglia are located near the thalamus and hypothalamus. An autopsy revealed mild atrophy of the frontal cortex and moderate atrophy of the thalamus. Strong synchronization of theta waves in the hippocampus and anterior ventral thalamus has been observed. These are the globus pallidus interna, thalamus, subthalamic nucleus and the pedunculopontine nucleus. These circuits carry information between the cortex, basal ganglia, thalamus, and back to the cortex. Most sensory information is routed to the cerebral cortex via the thalamus. Thalamocortical networks consist of neurons in both the thalamus and cortex. Substantia innominata connects the thalamus, temporal lobe, and insula. These tasks show activation in the frontal cortices, hippocampus and the thalamus for silent counting. These signals get to the primary visual cortex via the thalamus in tens of milliseconds. Dopamine tends to limit and select sensory information arriving from the thalamus to the forebrain. At the back of the thalamus is the brainstem. Other parts, such as the thalamus and hypothalamus, consist of clusters of many small nuclei. The diencephalon gives rise to the thalamus and hypothalamus.