Pseudocortical and dissociate discriminative sensory dysfunction in a thalamic stroke

Area of Science:

• Neuroscience
• Neurology
• Sensory processing

Background:

• Thalamic lesions are occasionally associated with pseudocortical syndromes.
• The impact of thalamic lesions on the cortical network for tactile recognition remains understudied.

Observation:

• A patient with a right thalamic stroke developed tactile agnosia in the left hand, presenting a pseudocortical sensory syndrome.
• Sensory dysfunction was dissociative, characterized by tactile agnosia and mild pseudoathetosis.

Findings:

• Functional magnetic resonance imaging (fMRI) revealed bilateral fronto-parietal network activation for tactile recognition with the unaffected hand.
• With the affected (left) hand, activation was restricted and lateralized to the ipsilateral hemisphere during tactile recognition.
• The absence of full cortical network activation in this patient suggests functional equivalence between pseudocortical and cortical tactile agnosia.

Implications:

• This case highlights the critical role of the thalamus in maintaining the integrity of the fronto-parietal network essential for tactile recognition.
• Findings suggest that thalamic lesions can lead to a functional deficit in tactile recognition comparable to cortical lesions.
• Understanding these network dynamics offers insights into sensory processing disorders and potential therapeutic targets.