On-line, voluntary control of human temporal lobe neurons

A visual brain–machine interface The brain has to continually select between a plethora of external sensory stimuli in order to focus on and process a few of them. Neurons in the medial temporal lobe (MTL) are selectively responsive to particular visual objects, and their activity is known to be modulated by cognitive effects. Cerf et al. have constructed a new brain–machine interface in which patients implanted with intracranial electrodes looking at superimposed computer images, when asked to make an image fade in or fade out, rapidly learnt to regulate neuronal activity of their MTL neurons in different subregions and hemispheres. They were able to increase the firing rate of certain cells while decreasing that of others and controlling the composite image content. This work provides direct evidence that humans can control the neuronal activity of their own visual neurons deep inside their own brain, and that such activity can be decoded to control devices. It is hoped that similar interface devices will one day boost the communication of patients with various neurological impairments, such as locked-in syndrome or motor neuron disease.