cortical neurons

Human cortical neural stem cells

Cortical neurons are located in the cerebral cortex of the brain, a region responsible for memory, thought, language, and consciousness. Neural stem cells are “immature” cells committed to become neurons and helper cells of the brain. Neurons are the liaison between our brain and the world. When we eat a lemon, neurons connected to our taste buds tell the brain that it’s sour. Messages from the brain can also be sent elsewhere, as when neurons command muscles to contract while lifting a heavy object.

Image by Kimmy Lorrain, BrainCells, Inc.

Researchers discover how parts of the brain work together, or alone

Our brains have billions of neurons grouped into different regions. These regions often work alone but sometimes must join forces. How do regions communicate selectively?

Stanford researchers may have solved a riddle about the inner workings of the brain, which consists of billions of neurons, organized into many different regions, with each region primarily responsible for different tasks.

The various regions of the brain often work independently, relying on the neurons inside that region to do their work. At other times, however, two regions must cooperate to accomplish the task at hand. The riddle is this: what mechanism allows two brain regions to communicate when they need to cooperate yet avoid interfering with one another when they must work alone?

In a paper published today in Nature Neuroscience, a team led by Stanford electrical engineering professor Krishna Shenoy reveals a previously unknown process that helps two brain regions cooperate when joint action is required to perform a task.

“This is among the first mechanisms reported in the literature for letting brain areas process information continuously but only communicate what they need to,” said Matthew T. Kaufman, who was a postdoctoral scholar in the Shenoy lab when he co-authored the paper.

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Novel form of experience-dependent plasticity in the adult brain revealed

Research by a team of scientists from Cologne, Munich and Mainz has shown an unprecedented degree of connectivity reorganization in newly-generated hippocampal neurons in response to experience, suggesting their direct contribution to the processing of complex information in the adult brain.

The hippocampus is an anatomical area of the brain classically involved in memory formation and modulation of emotional behavior. It is also one of the very few regions in the adult brain where resident neural stem cells generate new neurons life-long, thus providing the hippocampal circuitry with an almost unique renewal mechanism important for information processing and mood regulation. In response to experience and voluntary exercise, the amount of new neurons that are incorporated into the hippocampus increases. Dr. Matteo Bergami from CECAD Cologne (Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases) has joined efforts with scientists from Ludwig Maximilians University Munich and the University Medical Center of Johannes Gutenberg University Mainz to investigate whether experience, rather than merely promoting neurogenesis, also modifies the connectivity of new neurons.

The scientists successfully showed that the pattern of connectivity of new neurons, namely the number and types of inputs received by each new neuron, is not prefigured in the adult brain but can be significantly altered in response to complex environmental conditions. In fact, following environmental enrichment (EE) the innervation by both local hippocampal interneurons and long distance projection cortical neurons was substantially increased. However, while the inhibitory inputs were largely transient, cortical innervation remained elevated even after ending the exposure to EE. These findings reveal that exposure to complex environmental stimuli as well as their deprivation regulates the way new neurons become incorporated into the preexisting circuitry and thus, their engagement into hippocampal-dependent tasks.

These findings significantly contribute to deepening our understanding of how the brain responds to experience and how external stimuli are translated into stable changes of neuronal connectivity. The results will not only help to decipher how complex learning processes modify the brain’s plasticity, but may also create an experimental basis for investigating the maladaptive changes in brain connectivity associated with neurological and neuropsychiatric disorders such as epilepsy, depression, anxiety, and posttraumatic stress.

The research group’s results represent a crucial step towards realizing the broader vision of CECAD at the University of Cologne, namely to understand the molecular and cellular basis of aging-associated diseases as a means to developing new effective therapeutic strategies.

When we choose a thought and give it energy, it spreads into the fractal universal web of light, which then returns those thoughts to us as electro-chemical experiences which creates our individual perspective reality.

Right now your mind is remembering itself as this coded light spreads within your visual cortex .Liquid light realizations within the infinite mind of creation. Know thy self, know God/Universe/Source.

Cortical neurons (brain cell)

New insights into neural computations in cerebral cortex

Study by Max Planck Florida scientists points to an active role for dendrites in cortical processing.

Advancing our understanding of neural circuits in the cerebral cortex

The cerebral cortex is the largest and most complex area of the brain, comprising 20 billion neurons and 60 trillion synapses–a neuronal network whose proper function is critical for sensory perception, motor control, and cognition. The part of the cerebral cortex devoted to vision has played a key role in elucidating fundamental principles that are used by cortical circuits to encode information. Because edges supply a wealth of information about our visual world, neurons in visual cortex respond selectively to edge orientation, some preferring vertical edges, while others prefer horizontal, and all angles in between. Individual neurons also exhibit considerable diversity in their degree of selectivity, some responding to a narrow range of orientations, others to a broad range of orientations. These differences in selectivity are critical for accurately encoding the visual information in natural scenes, but the underlying mechanisms that account for this diversity remain unclear. In their recent publication in Nature Neuroscience, MPFI researchers Daniel Wilson, David Whitney, Ben Scholl and David Fitzpatrick describe how this diversity comes about and, in the process, provide new insights into the powerful role that dendrites play in cortical processing.

The research team addressed this issue using new microscopic imaging technologies that allowed them for the first time to assess the input/output functions of individual cortical neurons in the living brain. By using in vivo 2-photon calcium imaging, they were able to characterize the orientation tuning and spatial arrangement of synaptic inputs to the dendritic spines of individual neurons in ferret visual cortex, and compare dendritic spine and cell body responses.

The researchers found that they were able to reliably predict the orientation preference of individual neurons simply by adding up the responses of their dendritic spines. However, the responses of the dendritic spines did not account for the degree of orientation selectivity exhibited by individual neurons. In looking for factors that could account for differences in selectivity, they noticed that spines with similar orientation preference were often spatially clustered along the dendrite and that neurons that had a greater number of these clusters exhibited greater selectivity. They also discovered that this functional clustering was correlated with localized dendritic events that are likely to enhance the inputs from the clustered spines.

So not only did the researchers solve the riddle of orientation selectivity, they provided evidence that dendrites endow neurons with more computational power than previously thought. While this study focused specifically on information coding in visual cortex, it is likely that functional clustering of inputs within the dendritic field is a common principle influencing neuronal input/output functions throughout the cerebral cortex, significantly enhancing the brain’s information processing capabilities.