Related Experiment Video
Updated: Jun 17, 2026
10:19
Induction of an Isoelectric Brain State to Investigate the Impact of Endogenous Synaptic Activity on Neuronal Excitability In Vivo
Published on: March 31, 2016
Neocortex network activation and deactivation states controlled by the thalamus
Akio Hirata1, Manuel A Castro-Alamancos
1Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA.
Journal of Neurophysiology
|January 8, 2010
Summary
The thalamus, not just a sensory relay, controls neocortex activation states through thalamocortical cell firing. This finding reveals a new mechanism for regulating brain states and attention.
Area of Science:
- Neuroscience
- Systems Neuroscience
- Sensory Processing
Background:
- Neocortex activity shifts between desynchronized (arousal) and synchronized (quiescence) states.
- These shifts are typically linked to neuromodulators from basal forebrain and brain stem systems.
- Thalamocortical cells were thought only to relay sensory information.
Purpose of the Study:
- To investigate the role of thalamocortical cell spontaneous tonic firing in neocortex activation.
- To determine if the thalamus can influence neocortex activation states beyond sensory relay.
Main Methods:
- Utilized urethane-anesthetized rats.
- Applied cholinergic and noradrenergic stimulation to the somatosensory thalamus.
- Measured changes in thalamocortical cell tonic firing and neocortex activity.
Main Results:
- Thalamocortical cell tonic firing levels were modulated by cholinergic and noradrenergic stimulation.
- Variations in thalamocortical cell firing directly controlled neocortex activation and deactivation.
- Demonstrated that the thalamus can actively regulate neocortex state.
Conclusions:
- The thalamus plays a dual role: sensory information relay and neocortex state control.
- This thalamic control complements existing mechanisms involving basal forebrain and brain stem nuclei.
- Topographical organization allows for area-specific neocortex activation, potentially aiding sensory processing and attention.
More Related Videos
Related Concept Videos
01:27Diencephalon: Thalamus and Information Relay
The thalamus, often called “the gateway to the cerebral cortex,” is vital in processing and directing sensory and motor signals throughout the brain. Almost all inputs destined for the cerebral cortex, except for olfactory signals, are relayed through the thalamus. The thalamus is a sophisticated relay station, channeling information from various brain regions to the cerebral cortex, as well as a filter, prioritizing certain signals over others based on current physiological states or needs.
01:30Diencephalon: Anatomical Regions
The diencephalon, etymologically translated as 'through brain,' plays an integral role as the conduit between the cerebrum and the vast extent of the nervous system. However, the olfactory system is an exception, as it interfaces directly with the cerebrum. The diencephalon, deeply ensconced beneath the cerebrum, primarily consists of three paired structures — the thalamus, hypothalamus, and epithelamus. It also includes accessory structures such as the subthalamus, which houses the subthalamic...
01:23Somatosensory, Motor, and Association Cortex
The somatosensory cortex in the parietal lobes is crucial for interpreting sensory data such as touch, temperature, and proprioception. The somatosensory cortex, situated in the parietal lobes, plays a vital role in interpreting sensory information like touch, temperature, and proprioception—awareness of body position. This specialized brain region features an organized structure wherein neurons at the top primarily process sensations originating from the lower body. In contrast, those at the...
01:23Diencephalon: Hypothalamus and Coordination
The hypothalamus is a small yet highly complex and essential brain region that plays a crucial role in regulating various bodily functions. Anatomically, it is located at the base of the brain, just above the brainstem and below the thalamus, forming part of the limbic system.
The hypothalamus interacts with other brain regions, including the pituitary gland, through a direct physical connection called the hypothalamic-pituitary axis. The hypothalamus receives somatic and visceral inputs and...
The hypothalamus interacts with other brain regions, including the pituitary gland, through a direct physical connection called the hypothalamic-pituitary axis. The hypothalamus receives somatic and visceral inputs and...
01:25Neural Circuits
Neural circuits and neuronal pools are two of the main structures found in the nervous system. Neural circuits are networks of neurons that work together to carry out a specific task or process. They consist of interconnected neurons and glial cells, which provide structural and metabolic support.
Neuronal pools are collections of nerve cells with similar functions and interact through chemical and electrical signals. These pools include both interneurons (the central neural circuit nodes that...
Neuronal pools are collections of nerve cells with similar functions and interact through chemical and electrical signals. These pools include both interneurons (the central neural circuit nodes that...
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.