James B. Ranck Jr. (born 1930) is a distinguished professor of Physiology at the SUNY Downstate Medical Center. His research involves recording from single neurons in living animals for behavioral studies. [1] He discovered head-direction cells in 1984.
Ranck was born August 17, 1930, in Frederick, Maryland, where his father was a history teacher at Hood College. He attended Haverford College (BA, 1951) and Columbia Medical School (MD, 1955). He interned at the University of Chicago (55-56) and worked at the Laboratory of Neuroanatomy at NIH (1956–58). After NIH he did post-doctoral work in the laboratory of Walter Woodbury at the University of Washington from 1959 to 1960, and was an instructor in biophysics at the same institution (60-61).
Ranck's initial faculty appointment was at the University of Michigan, Dept of Physiology from 1962 to 1975. He was appointed as professor in the Department of Physiology at Downstate in 1975, and distinguished Professor there in 2005.
There have been two distinct phases to Ranck's research career. From 1959 until 1973 Ranck analyzed the flow of electric current in brain, electrical properties of glia, electric impedance of brain, release of potassium from neurons in a seizure, and which elements are activated in electric stimulation of brain. [2]
In 1967, while analyzing the biophysical properties of the subiculum he found that impedance increased in REM sleep. Using recently developed small, sturdy field effect transistors, he then started to record from single neurons in the hippocampal formation in behaving rats. From 1967 to 1969 Ranck tried numerous electronic and surgical approaches before getting stable single-neuron recordings. Enabled by these new recording methods, Ranck' began to study the firing properties and behavioral correlates of neurons in the limbic system. [3]
In the early phase Ranck studied impedance in the brain, providing basic data for any studies or procedures that employ electrical stimulation of the CNS. Later, he was among the first to record from single neurons in awake behaving animals (rats). [4] At first he recorded from the hippocampus, and largely confirmed O'Keefe's description of place cells. In 1984, Ranck discovered Head-Direction cells in a neighboring structure, the post-subiculum, adding a second ingredient to the navigation system of the brain.
In collaboration with Steven Fox, Ranck characterized complex-spike cells and theta cells in the hippocampal formation. [5] John Kubie and Ranck characterized hippocampal place cells in three separate environments and postulated that hippocampal neurons code context as well as place. Kubie, Bob Muller and Ranck then used quantitative, automated techniques to demonstrate the hippocampal place cells and describe their characteristics.
Ranck is best known for his discovery of Head-Direction cells. [6] Before that time, scientists didn't know how 'directional sense' was coded in a mammal's brain, and it was assumed to be a complex function. Ranck, working alone, attempted to describe the firing properties of neurons in retro-hippocampal areas. He observed clear directional firing properties when neurons were recorded in the dorsal pre-subiculum. Ranck made his initial report in a 1984 abstract for the meeting of the Society for Neuroscience. It took several years to get a stable two-spot recording system. Working with Jeffrey Taube and Bob Muller two papers were published in the Journal of Neuroscience in 1990.
Ranck married Helen Haukeness in 1961. They have a daughter, Mary Ranck Bolieu.
The dentate gyrus (DG) is part of the hippocampal formation in the temporal lobe of the brain, which also includes the hippocampus and the subiculum. The dentate gyrus is part of the hippocampal trisynaptic circuit and is thought to contribute to the formation of new episodic memories, the spontaneous exploration of novel environments and other functions.
In neurophysiology, long-term depression (LTD) is an activity-dependent reduction in the efficacy of neuronal synapses lasting hours or longer following a long patterned stimulus. LTD occurs in many areas of the CNS with varying mechanisms depending upon brain region and developmental progress.
A place cell is a kind of pyramidal neuron in the hippocampus that becomes active when an animal enters a particular place in its environment, which is known as the place field. Place cells are thought to act collectively as a cognitive representation of a specific location in space, known as a cognitive map. Place cells work with other types of neurons in the hippocampus and surrounding regions to perform this kind of spatial processing. They have been found in a variety of animals, including rodents, bats, monkeys and humans.
The motor cortex is the region of the cerebral cortex involved in the planning, control, and execution of voluntary movements. The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately anterior to the central sulcus.
The periaqueductal gray is a brain region that plays a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. PAG is also the primary control center for descending pain modulation. It has enkephalin-producing cells that suppress pain.
The subiculum is the most inferior component of the hippocampal formation. It lies between the entorhinal cortex and the CA1 subfield of the hippocampus proper.
Head direction (HD) cells are neurons found in a number of brain regions that increase their firing rates above baseline levels only when the animal's head points in a specific direction. They have been reported in rats, monkeys, mice, chinchillas and bats, but are thought to be common to all mammals, perhaps all vertebrates and perhaps even some invertebrates, and to underlie the "sense of direction". When the animal's head is facing in the cell's "preferred firing direction" these neurons fire at a steady rate, but firing decreases back to baseline rates as the animal's head turns away from the preferred direction.
Area 27 of Brodmann-1909 is a cytoarchitecturally defined cortical area that is a rostral part of the parahippocampal gyrus. It is commonly regarded as a synonym of presubiculum.
Theta waves generate the theta rhythm, a neural oscillation in the brain that underlies various aspects of cognition and behavior, including learning, memory, and spatial navigation in many animals. It can be recorded using various electrophysiological methods, such as electroencephalogram (EEG), recorded either from inside the brain or from electrodes attached to the scalp.
Temporal lobe epilepsy (TLE) is a chronic disorder of the nervous system which is characterized by recurrent, unprovoked focal seizures that originate in the temporal lobe of the brain and last about one or two minutes. TLE is the most common form of epilepsy with focal seizures. A focal seizure in the temporal lobe may spread to other areas in the brain when it may become a focal to bilateral seizure.
The septal area, consisting of the lateral septum and medial septum, is an area in the lower, posterior part of the medial surface of the frontal lobe, and refers to the nearby septum pellucidum.
A grid cell is a type of neuron within the entorhinal cortex that fires at regular intervals as an animal navigates an open area, allowing it to understand its position in space by storing and integrating information about location, distance, and direction. Grid cells have been found in many animals, including rats, mice, bats, monkeys, and humans.
The premotor cortex is an area of the motor cortex lying within the frontal lobe of the brain just anterior to the primary motor cortex. It occupies part of Brodmann's area 6. It has been studied mainly in primates, including monkeys and humans. The functions of the premotor cortex are diverse and not fully understood. It projects directly to the spinal cord and therefore may play a role in the direct control of behavior, with a relative emphasis on the trunk muscles of the body. It may also play a role in planning movement, in the spatial guidance of movement, in the sensory guidance of movement, in understanding the actions of others, and in using abstract rules to perform specific tasks. Different subregions of the premotor cortex have different properties and presumably emphasize different functions. Nerve signals generated in the premotor cortex cause much more complex patterns of movement than the discrete patterns generated in the primary motor cortex.
In the rodent, the parasubiculum is a retrohippocampal isocortical structure, and a major component of the subicular complex. It receives numerous subcortical and cortical inputs, and sends major projections to the superficial layers of the entorhinal cortex.
Hippocampus anatomy describes the physical aspects and properties of the hippocampus, a neural structure in the medial temporal lobe of the brain. It has a distinctive, curved shape that has been likened to the sea-horse monster of Greek mythology and the ram's horns of Amun in Egyptian mythology. This general layout holds across the full range of mammalian species, from hedgehog to human, although the details vary. For example, in the rat, the two hippocampi look similar to a pair of bananas, joined at the stems. In primate brains, including humans, the portion of the hippocampus near the base of the temporal lobe is much broader than the part at the top. Due to the three-dimensional curvature of this structure, two-dimensional sections such as shown are commonly seen. Neuroimaging pictures can show a number of different shapes, depending on the angle and location of the cut.
The Mauthner cells are a pair of big and easily identifiable neurons located in the rhombomere 4 of the hindbrain in fish and amphibians that are responsible for a very fast escape reflex. The cells are also notable for their unusual use of both chemical and electrical synapses.
Environmental enrichment is the stimulation of the brain by its physical and social surroundings. Brains in richer, more stimulating environments have higher rates of synaptogenesis and more complex dendrite arbors, leading to increased brain activity. This effect takes place primarily during neurodevelopment, but also during adulthood to a lesser degree. With extra synapses there is also increased synapse activity, leading to an increased size and number of glial energy-support cells. Environmental enrichment also enhances capillary vasculation, providing the neurons and glial cells with extra energy. The neuropil expands, thickening the cortex. Research on rodent brains suggests that environmental enrichment may also lead to an increased rate of neurogenesis.
Erythropoietin in neuroprotection is the use of the glycoprotein erythropoietin (Epo) for neuroprotection. Epo controls erythropoiesis, or red blood cell production.
Edward Roy Perl was an American neuroscientist whose research focused on neural mechanisms of and circuitry involved in somatic sensation, principally nociception. Work in his laboratory in the late 1960s established the existence of unique nociceptors. Perl was one of the founding members of the Society for Neuroscience and served as its first president. He was a Sarah Graham Kenan Professor of Cell Biology & Physiology and a member of the UNC Neuroscience Center at the University of North Carolina School of Medicine.
The dorsal tegmental nucleus (DTN), also known as dorsal tegmental nucleus of Gudden (DTg), is a group of neurons located in the brain stem, which are involved in spatial navigation and orientation.