Multisensory convergence in the thalamus of the pigeon (Columba livia)

Neuronal activity was extracellularly recorded from the nucleus dorsolateralis posterior thalami (DLP) of anesthetized pigeons. The sensitivity of individual cells to stimuli of different sensory modalities: somatosensory, visual and auditory was investigated. A substantial population of the DLP neurons responded to mechanical stimulation of large, often bilateral areas of the animal's body surface. No somatotopic organization could be detected. The functional properties of these neurons resembled those described for mammalian nucleus posterior thalami neurons. The visually responsive cells could be driven from large areas of the visual field. Auditory sensitive neurons were optimally activated by wideband noise. Twenty-nine percent of the DLP recorded neurons showed polysensory properties responding either to somatosensory and visual or to somatosensory and auditory stimuli.