Control of brain waves from the brain surface

Control of brain waves from the brain surface
Credit: Thinkstock

Whether or not a neuron transmits an electrical impulse is a function of many factors. European research is using a heady mixture of techniques – molecular, microscopy and electrophysiological – to identify the necessary input for nerve transmission in the cortex.

In the central nervous system (CNS), a nerve cell or neuron has a 'forest' of elaborate dendritic trees arising from the cell body. These literally receive many thousands of synapses (junctions that allow transmission of a signal) at positions around the tree. These inputs then are able to generate an impulse, or 'spike', known as an action potential at the initial part of the axon.

Previous research has confirmed that an activated synapse will generate an electric signal as a result of neurotransmitters released from pre-synaptic axons. Electrical recordings from the neocortex have confirmed that, in line with the cable theory prediction, that modulation of potential at the dendrite is highly distance-dependent from the cell body or soma.

The 'Information processing in distal dendrites of neocortical layer 5 pyramidal neurons' (Channelrhodopsin) project aimed to shed more light on how more distal sites in the 'tree' influence the action potential of the post-synaptic neuron. Furthermore, they investigated exactly how dendritic spikes can be generated, another issue about which there is little information so far.

Recent research has highlighted the importance of activation of N-methyl-D-aspartate (NMDA) receptors to bring about the production of a signal that will proceed to the soma and then result in a spike. There is also indirect evidence that interneurons targeting dendrites can control level of dendrite excitability.

Channelrhodopsin scientists simultaneously recorded the pre- and post-synaptic electrical recordings of identified interneurons and a special type of neuron, pyramidal cells that are primary excitation units in the mammalian cortex.

The project team first characterised the different types of inhibitory neuron deep in the cortex in layer 5 at apical tuft dendrites. The researchers then showed that a special type of inhibitory interneuron in the outer layer of the neocortex can suppress dendritic spiking in layer 5.

Project results show that a superficial inhibitory neuron can impact information processing in a specific pyramidal neuron. The research will have massive implications for neuroscience and help to unravel the integrative operations of CNS .

add to favorites email to friend print save as pdf

Related Stories

Neurons found to be similar to Electoral College

Sep 14, 2009

A tiny neuron is a very complicated structure. Its complex network of dendrites, axons and synapses is constantly dealing with information, deciding whether or not to send a nerve impulse, to drive a certain action.

Digital versus analog control over cortical inhibition

Mar 22, 2011

In the cerebral cortex, the balance between excitation (pyramidal neurons) and inhibition (interneurons) is thought to be mediated by the primary mode of neuronal communication: "all-or-none" action potentials, or spikes. ...

What makes an axon an axon?

Nov 10, 2008

Inside every axon is a dendrite waiting to get out. Hedstrom et al. converted mature axons into dendrites by banishing a protein crucial for neuron development. The results suggest that this transformation could occur after ...

Recommended for you

Common infections tied to some stroke risk in kids

2 hours ago

A new study suggests that colds and other minor infections may temporarily increase stroke risk in children. The study found that the risk of stroke was increased only within a three-day period between a ...

Celebrities in 'Ice Bucket Challenge' to fight disease

13 hours ago

Steven Spielberg, Justin Bieber and Bill Gates are among many celebrities pouring buckets of ice water over their heads and donating to fight Lou Gehrig's disease, in a fundraising effort that has gone viral.

Study helps explain why elderly have trouble sleeping

14 hours ago

As people grow older, they often have difficulty falling asleep and staying asleep, and tend to awaken too early in the morning. In individuals with Alzheimer's disease, this common and troubling symptom ...

Targeted brain training may help you multitask better

16 hours ago

The area of the brain involved in multitasking and ways to train it have been identified by a research team at the IUGM Institut universitaire de gériatrie de Montréal and the University of Montreal.

User comments