Thalamic and Hypothalamic Syndromes

Abstract

Each sensory modality, with the exception of olfaction, travels from its receptors via tracts to the thalamic nuclei within each brain (Powell et al. 1965; Price). From here, information is relayed on to the primary cortical projection area for each modality via the thalamic radiations. It follows that a thalamic stroke may present with vague, ill-defined sensory complaints that are initially somewhat hard to nail down and which may fluctuate or wax and wane over time. But the hallucinations derived from altered activation of the thalamic nuclei may be multimodal, corresponding with the very close proximity across systems with vision at the lateral geniculate (LG) nucleus, audition at the medial geniculate (MG) nucleus, somesthesis at the ventral posterior lateral (VPL) nucleus, and with motor fibers from the motor cortex projecting to the ventral lateral (VL) nucleus of the thalamus.