Research

Murray Sherman is a distinguished neuroscientist and widely known for his pioneering work on the thalamus and its role in sensory processing, cognition, and consciousness. His research has significantly advanced our understanding of how the thalamus acts not just as a relay center for sensory information but also as an active participant in information processing and higher-order brain functions.

One of Sherman’s most influential contributions has been his work on classifying thalamic relay cells. Traditionally, the thalamus was considered a simple relay station that passively transmitted sensory signals from the periphery to the cortex. However, Sherman, along with his collaborator Ray Guillery, challenged this view by introducing the distinction between first order and higher order thalamic relays. First order relays, such as the lateral geniculate nucleus (LGN) for vision and the ventral posterior nucleus for somatosensation, transmit peripheral sensory information to primary sensory cortical areas. In contrast, higher order relays, such as the pulvinar, are involved in cortico-thalamo-cortical communication, playing a key role in cognition, attention, and learning. This conceptual framework reshaped the understanding of thalamocortical interactions and emphasized the thalamus’s role in coordinating cortical activity.

Sherman also made significant contributions to the study of thalamocortical circuits by identifying the importance of different types of synapses in thalamic processing. He demonstrated that thalamic relay cells receive two main types of synaptic inputs: driver inputs, which convey the primary sensory or motor signals, and modulator inputs, which influence the relay cells’ response properties and regulate attention and state-dependent processing. This distinction provided a mechanistic basis for understanding how the thalamus processes and filters information before transmitting it to the cortex.

Another key aspect of Sherman’s research involved the role of thalamic bursts and tonic firing modes in sensory processing. He showed that thalamic relay neurons can switch between burst and tonic firing modes depending on the neurons’ membrane potential history. In the burst mode, neurons generate clusters of action potentials that enhance signal detection, while the tonic mode allows for more linear transmission of sensory information. This finding had profound implications for understanding how sensory information is dynamically processed based on an organism’s level of alertness.

Sherman’s contributions to neuroscience extend beyond experimental findings, his theoretical models, reviews, and books, such as Exploring the Thalamus and Its Role in Cortical Function, have been instrumental in shaping modern views of thalamocortical function. His work has influenced a broad range of fields, from vision research to computational neuroscience, and continues to inspire new investigations into the role of the thalamus in perception, consciousness, and neurological disorders.