The ventrolateral nucleus (VL) of the thalamus is connected to the cerebellum and motor cortex and therefore thought to be involved in motor function.
A new study to be published in Annals of Neurology, the official journal of the American Neurological Association, found that the VL also plays a role in sensory processing and that damage to this area leads to functional and neural changes. The journal is available online via Wiley InterScience at http://www.interscience.wiley.com/journal/ana.
Investigations of the human VL have been limited to date, due to a lack of tools available to examine its function and the fact that lesions that occur in this region tend to be larger and therefore affect more than one nucleus of the thalamus. Thalamic nuclei are dense clumps of nerve cells found where the fibers from sensory systems terminate in the thalamus. Led by Tony Ro, of Rice University in Houston, TX, researchers conducted a series of behavioral and neuroimaging studies on a patient who had suffered a stroke affecting only the right VL, a rare occurrence. She had reported changes to her sensory abilities, such as bumping into the left sides of doorways or veering right when driving as a result of decreased sensations on the affected (left) side, but was otherwise normal. The patient was tested using visual and tactile stimuli and also underwent diffusion tensor imaging (DTI) scans, an imaging method that uses a magnetic resonance imaging (MRI) scanner to visualize the neuron fibers and connectivity in the brain. Experiments were conducted one, three and six years following the patient's stroke.