Robert T. Knight
My laboratory studies the contribution of subregions of human prefrontal cortex to the control of cognitive and social behavior. We employ electrophysiological, MRI and behavioral techniques in neurological patients with frontal lobe damage in an effort to understand the neural mechanisms of cognitive processing.
Current Projects
The laboratory employs neuroanatomical, electrophysiological, blood flow, neuropsychological and behavioral techniques to study attention and memory mechanisms in humans. A long standing interest has centered on behavioral and physiological study of human dorsolateral prefrontal cortex. Ongoing work in this area includes studies of sensory gating, working memory, sustained attention, language and novelty detection. Experimental subjects are typically neurological patients with CT or MRI scan defined damage in subregions of prefrontal cortex and age matched controls. Lesions are further defined by high resolution 3-D MRI scanning. The contribution of prefrontal cortex to age related changes is also an active ongoing topic of inquiry. Converging evidence from experiments in neurological patients in the visual, auditory and somatosensory modalities has documented a critical regulatory role of dorsolateral prefrontal cortex in multiple tasks. Prefrontal cortex modulates both inhibitory and excitatory activity in distributed neural networks with apparent differential contributions from dorsal and ventral prefrontal subregions. In addition to a role in modulation of sensory processing, a prefrontal-hippocampal network is also selectively engaged by novel events and this phenomena is currently being investigated in several studies. Although dorsal and ventral prefrontal cortex has been the main area of research, more recently we have begun to examine patients with discrete orbito-frontal damage with additional interests in the neural control of emotion.
Over the last few years, the laboratory has also begun investigation of mesial temporal function with a particular emphasis on the relationship of novelty detection, and the influence of prefrontal-hippocampal interactions on subsequent memory for distinct unusual events. Other studies are investigating the role of subregions of the mesial temporal region in familiarity and recognition memory and in memory binding. The experimental subjects in the mesial temporal experiments include patients with unilateral infarction of the posterior hippocampus and adjacent structures due to posterior cerebral artery occlusion and patients with CA1 hypoxic damage. The laboratory employs neuroanatomical, electrophysiological, blood flow, neuropsychological and behavioral techniques to study attention and memory mechanisms in humans. A long standing interest has centered on behavioral and physiological study of human dorsolateral prefrontal cortex. Ongoing work in this area includes studies of sensory gating, working memory, sustained attention, language and novelty detection. Experimental subjects are typically neurological patients with CT or MRI scan defined damage in subregions of prefrontal cortex and age matched controls. Lesions are further defined by high resolution 3-D MRI scanning. The contribution of prefrontal cortex to age related changes is also an active ongoing topic of inquiry. Converging evidence from experiments in neurological patients in the visual , auditory and somatosensory modalities has documented a critical regulatory role of dorsolateral prefrontal cortex in multiple tasks. Prefrontal cortex modulates both inhibitory and excitatory activity in distributed neural networks with apparent differential contributions from dorsal and ventral prefrontal subregions. In addition to a role in modulation of sensory processing, a prefrontal-hippocampal network is also selectively engaged by novel events and this phenomena is currently being investigated in several studies. Although dorsal and ventral prefrontal cortex has been the main area of research, more recently we have begun to examine patients with discrete orbito-frontal damage with additional interests in the neural control of emotion.
Over the last few years, the laboratory has also begun investigation of mesial temporal function with a particular emphasis on the relationship of novelty detection, and the influence of prefrontal-hippocampal interactions on subsequent memory for distinct unusual events. Other studies are investigating the role of subregions of the mesial temporal region in familiarity and recognition memory and in memory binding. The experimental subjects in the mesial temporal experiments include patients with unilateral infarction of the posterior hippocampus and adjacent structures due to posterior cerebral artery occlusion and patients with CA1 hypoxic damage.
In the News
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Six UC Berkeley faculty elected AAAS fellows
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Will computers ever truly understand what we’re saying?
From Apple’s Siri to Honda’s robot Asimo, machines seem to be getting better and better at communicating with humans. But some neuroscientists caution that today’s computers will never truly understand what we’re saying.
Brain’s iconic seat of speech goes silent when we actually talk
The brain’s speech area, named after 19th century French physician Pierre Paul Broca, shuts down when we talk out loud, according to a new study that challenges the long-held belief that “Broca’s area” governs all aspects of speech production.
Study links honesty to prefrontal region of the brain
Are humans programmed to tell the truth? Not when lying is advantageous, says a new study led by Assistant Professor Ming Hsu at UC Berkeley’s Haas School of Business. The report ties honesty to a region of the brain that exerts control over automatic impulses.
CNEP researchers target brain circuitry to treat intractable mental disorders
Neuroscientists, engineers and physicians are teaming up for an ambitious five-year, $26 million project to develop new techniques for tackling mental illness.
Scientists decode brain waves to eavesdrop on what we hear
Neuroscientists may one day be able to hear the imagined speech of a patient unable to speak due to stroke or paralysis, according to University of California, Berkeley, researchers
Science decodes 'internal voices"
Berkeley researchers have demonstrated a way to reconstruct words, based on the brain waves of patients thinking of those words.
UC Berkeley, UCSF join forces to advance frontier of brain repair
Researchers at UC Berkeley and UCSF have launched the joint Center for Neural Engineering and Prostheses to develop technology that can translate brain signals into movements controlling prosthetic limbs, circumventing damaged or missing neural circuits in people suffering from disabling conditions.
Our brains are wired so we can better hear ourselves speak, new study shows
Like the mute button on the TV remote control, our brains filter out unwanted noise so we can focus on what we’re listening to. But when it comes to following our own speech, a new brain study from UC Berkeley shows that instead of one homogenous mute button, we have a network of volume settings that can selectively silence and amplify the sounds we make and hear.
Phantom images stored in flexible network throughout brain
The ability to store phantom images in our brain in order to make visual comparisons is impaired by damage to the prefrontal cortex, but intact regions of the prefrontal cortex pick up the slack in less than a second. Damage to the basal ganglia, however, causes more widespread impairment of visual working memory. New studies by UC Berkeley neuroscientists show how the prefrontal cortex flexibly picks up new functions while retaining old.
Research restructuring leads to net reduction in jobs
In mid-July, Vice Chancellor for Research Graham R. Fleming announced that the dire budget circumstances facing the campus necessitated taking a hard look, as quickly as possible, at the structure of services and deployment of resources administered from his office.