L9 Basal Ganglia

A region within the basal ganglia that releases acetylcholine to modulate activity in the nigrostriatal pathway.

The part of the substantia nigra that produces dopamine and projects to the striatum. Not shown in the diagram.

The lateral segment of the globus pallidus, located in the outer portion of the structure. It plays a role in inhibiting movement.

A group of brain structures that are essential for the coordination and control of movement.

A typical scenario involving the basal ganglia. The output nuclei of the basal ganglia normally "inhibit" the motor cortex and thalamus, preventing spontaneous movement.

A brain region that acts as a "brake" on movement by inhibiting the thalamus and motor cortex, preventing spontaneous actions.

A pathway within the basal ganglia that helps to initiate movement by disinhibiting the thalamus and motor cortex.

A pathway within the basal ganglia that primarily inhibits movement by activating the subthalamic nucleus and thus indirectly inhibiting the thalamus and motor cortex.

A brain area involved in regulating movement control, particularly in the indirect pathway.

A brain region that projects dopamine to the striatum, playing a crucial role in facilitating movement.

A brain structure within the basal ganglia that receives input from the cortex and projects to both the direct and indirect pathways.

The primary inhibitory neurotransmitter used in the basal ganglia, responsible for inhibiting the thalamus and motor cortex.

Caused by a high level of basal ganglia activity, this allows for multiple actions to occur simultaneously.

The default state of the brain, characterized by a balance of inhibiting and excitatory signals, allowing for a state of rest and readiness.

A neurotransmitter associated with reducing neuronal activity, promoting calmness and relaxation. It plays a key role in the default brain state.

A brain structure crucial for sensory information processing and relaying it to other parts of the brain, contributing to the overall activity of the brain.

A neurotransmitter primarily associated with stimulating neuronal activity, promoting action and movement. It plays a key role in activating the brain for motor control.

A brain structure involved in planning and executing movements; it receives input from the basal ganglia to regulate motor function.

A pathway within the basal ganglia responsible for globally inhibiting ongoing motor activities, allowing for transitioning to new motor patterns.

The process of prioritizing and shifting attention from one action to another based on new information, often involving the hyperdirect pathway within the basal ganglia.

The indirect pathway in the basal ganglia primarily inhibits movement by activating the subthalamic nucleus (STN). This activation leads to increased inhibition of the thalamus and motor cortex, ultimately suppressing unwanted movements.

The direct pathway within the basal ganglia facilitates movement by disinhibiting the thalamus and motor cortex. This results in increased activation of the motor cortex, leading to a specific motor action.

The striatum, composed of the caudate and putamen, receives input from the cortex and relays this information to both the direct and indirect pathways, influencing movement initiation and suppression.

The lateral globus pallidus (GPL), an output structure of the basal ganglia, plays a crucial role in inhibiting movement by sending inhibitory signals to the thalamus and motor cortex, ensuring smooth and controlled movements.

The subthalamic nucleus (STN), located in the diencephalon, is a key player in the indirect pathway. It receives input from the globus pallidus and projects to the substantia nigra pars reticulata, contributing to movement suppression.

The substantia nigra pars reticulata (SNpr) projects to the thalamus, contributing to movement suppression by inhibiting thalamocortical neurons. This inhibition helps to refine and modulate movements.

The basal ganglia, a group of subcortical structures, play a crucial role in planning and coordinating movement. They receive input from the cortex and project to the thalamus, influencing motor activity.

The direct pathway and indirect pathway work together to create a balanced control system for movement. The direct pathway facilitates desired movement, while the indirect pathway suppresses competing or unwanted movements, resulting in precise and efficient action.

The part of the basal ganglia that receives input from the cortex and projects to both the direct and indirect pathways.

The output nuclei of the basal ganglia are the Globus Pallidus (internal) and the Substantia Nigra pars Reticularis. These nuclei are responsible for inhibiting the thalamus and motor cortex.

The direct pathway in the basal ganglia facilitates movement by directly disinhibiting the thalamus. It involves fewer inhibitory synapses.

The indirect pathway in the basal ganglia inhibits movement by increasing inhibition of the thalamus. It involves more inhibitory synapses.

The Subthalamic Nucleus (STN) is a crucial part of the indirect pathway, acting as an intermediary in reducing thalamus activity.

The Medial Globus Pallidus (GPi) is one of the output nuclei in the basal ganglia, which plays a critical role in inhibiting the thalamus via GABA neurotransmission.

GABA (Gamma-aminobutyric acid) is the primary inhibitory neurotransmitter used in the basal ganglia, responsible for inhibiting the thalamus and motor cortex.

The basal ganglia are a group of brain regions involved in controlling movement, learning, and other functions. They influence movement through the thalamus and motor cortex.

Dopamine plays a key role in controlling movement by affecting the activity of the indirect pathway. In Parkinson's disease, the loss of dopamine neurons in the substantia nigra leads to an imbalance in the balance of activity, where the indirect pathway becomes more active. The decreased dopamine levels result in increased inhibition of movement, leading to the characteristic symptoms of the disease.

The subthalamic nucleus (STN) plays a crucial role in the indirect pathway, amplifying its inhibitory effect on movement. It receives excitatory input from the globus pallidus external segment (GPe) and projects to the globus pallidus internal segment (GPi), further increasing the inhibition of the thalamus and motor cortex.

The globus pallidus internal segment (GPi) is the final output structure of the indirect pathway. It receives input from the subthalamic nucleus (STN) and projects to the thalamus. The GPi is highly active in inhibiting movement in the indirect pathway. In Parkinson's disease, the decreased inhibition of the GPi leads to increased inhibition of the thalamus, contributing to the slowness of movement.

The striatum is a key structure at the beginning of both the direct and indirect pathways, acting like a 'decision maker' for movement. It receives input from the cortex and integrates information from various brain regions. The striatum also receives input from the substantia nigra pars compacta (SNpc), which sends dopamine to modulate the activity of the striatum. The activity level of the striatum determines the relative activity of the direct and indirect pathways.

The globus pallidus external segment (GPe) is a crucial structure in the indirect pathway, responsible for inhibiting the subthalamic nucleus (STN). The GPe receives input from the striatum and projects to the STN, helping to modulate the activity of the indirect pathway. GPe dysfunction can lead to hyperkinetic movements, such as dystonia.

The direct pathway facilitates movement by disinhibiting the thalamus, while the indirect pathway inhibits movement by activating the subthalamic nucleus (STN) and indirectly inhibiting the thalamus. The balance between these two pathways is critical for smooth and coordinated movement. This balance is affected by the level of dopamine in the brain.

The indirect pathway plays a fundamental role in regulating movement by inhibiting spontaneous or unwanted actions. This is essential for maintaining a resting state and preventing involuntary movements. It allows us to control our movements intentionally and prevents undesired or uncontrolled actions.

A brain structure that receives input from the cerebral cortex and sends output to the thalamus, regulating movement via the direct and indirect pathways.

A neurotransmitter involved in controlling movement in the basal ganglia. It is released in both the direct and indirect pathways, affecting the balance between movement facilitation and inhibition.

A hyperkinetic movement disorder characterized by slow, writhing, involuntary movements, primarily affecting the upper body.

One of the output nuclei of the basal ganglia, responsible for inhibiting movement by sending inhibitory signals to the thalamus.

A key structure located in the midbrain that produces dopamine. Its neurons project to the striatum and play a critical role in regulating movement.

The Hyperdirect Pathway directly inhibits the motor thalamus and cortex using a high concentration of inhibitory neurotransmitters, causing a rapid suppression of ongoing motor activities.

The Hyperdirect Pathway acts like an emergency brake, abruptly reducing motor activity to prepare for a new movement, allowing for swift transitions between motor patterns.

Unlike the Direct Pathway, which uses small, unmyelinated axons, the Hyperdirect Pathway utilizes large, myelinated axons. This allows for faster signal transmission, crucial for its immediate inhibitory effect.

The Hyperdirect Pathway is so named because it directly connects the motor cortex to the subthalamic nucleus, bypassing the intermediate structures used in the Direct and Indirect Pathways.

The Hyperdirect Pathway's rapid inhibition helps facilitate smooth transitions between motor activities. It prevents interference from previous movements while initiating new ones.

The internal globus pallidus (GPi) is the final output structure of the indirect pathway. It receives input from the STN and projects to the thalamus, further inhibiting thalamocortical neurons, ultimately leading to decreased movement.

The external globus pallidus (GPe) is another structure in the indirect pathway. It receives input from the striatum and projects to the STN. The GPe regulates the activity of the STN, allowing for fine-tuning of the inhibitory signals.

Both the direct pathway and the indirect pathway work together to regulate movement. The direct pathway facilitates movement, while the indirect pathway inhibits movement. Their balance is crucial for smooth and coordinated voluntary actions.

The indirect pathway plays a critical role in preventing unwanted movements and maintaining a resting state. It helps us control our actions intentionally and smoothly.

Dopamine is a crucial neurotransmitter involved in regulating movement by modulating the activity of both the direct and indirect pathways. An imbalance in dopamine levels can lead to disorders like Parkinson's disease, where the indirect pathway becomes overly active, causing movement problems.

A condition characterized by involuntary, repetitive muscle movements, primarily affecting the face, mouth, and tongue. It is often caused by long-term use of dopamine antagonist antipsychotic medications and can be irreversible.

A neurological disorder marked by large, sudden, and violent involuntary movements of the limbs, often causing a flailing or flinging motion. It is caused by damage to the basal ganglia, specifically the subthalamic nucleus.

Involuntary, persistent, and repetitive movements that are often complex and purposeless, such as arranging objects or manipulating things repeatedly. It can be caused by dopamine imbalances in the mesolimbic pathway.

A type of gait characterized by the legs moving in a stiff, scissor-like motion, often caused by spasticity in the muscles of the legs and hips.

A type of gait characterized by dragging the foot on the ground, typically due to weakness or paralysis of the leg muscles. It is often seen in people with cerebral palsy or stroke.

A disorder characterized by problems with muscle movement and coordination, typically caused by damage to the brain during pregnancy or shortly after birth. It is non-progressive, meaning symptoms do not worsen over time.

A toxic substance found in household products such as windshield washer fluid, paint removers, and antifreeze. Ingestion can lead to serious health problems like blindness and brain damage.

The direct pathway in the basal ganglia helps initiate movements by directly inhibiting the thalamus and motor cortex.

The striatum, composed of the caudate and putamen, receives input from the cortex and relays this information to both the direct and indirect pathways, influencing movement initiation and suppression.

The lateral globus pallidus (GPL), an output structure of the basal ganglia, plays a crucial role in inhibiting movement by sending inhibitory signals to the thalamus and motor cortex, ensuring smooth and controlled movements.

The subthalamic nucleus (STN) plays a crucial role in the indirect pathway, amplifying its inhibitory effect on movement by receiving input from the globus pallidus external segment (GPe) and projecting to the globus pallidus internal segment (GPi).

The globus pallidus external segment (GPe) inhibits the subthalamic nucleus (STN), helping to modulate the activity of the indirect pathway. GPe dysfunction can lead to hyperkinetic movements, such as dystonia.

The direct pathway facilitates movement by disinhibiting the thalamus, while the indirect pathway inhibits movement by activating the subthalamic nucleus (STN) and indirectly inhibiting the thalamus. The balance between these two pathways is critical for smooth and coordinated movement. This balance is affected by the level of dopamine in the brain.

The indirect pathway plays a fundamental role in regulating movement by inhibiting spontaneous or unwanted actions. This is essential for maintaining a resting state and preventing involuntary movements. It allows us to control our movements intentionally and prevents undesired or uncontrolled actions.

A pathway in the basal ganglia that directly inhibits the thalamus and motor cortex, resulting in a rapid suppression of ongoing motor activity.

The Hyperdirect Pathway suppresses ongoing movements to allow for the initiation of new motor patterns, enabling fast and efficient motor adjustments.

The direct pathway facilitates movement by directly inhibiting the thalamus and motor cortex, allowing for a specific action to be initiated. It involves fewer inhibitory synapses, leading to a quicker response.

The indirect pathway inhibits movement by activating the subthalamic nucleus (STN), which further inhibits the thalamus and motor cortex. It involves more inhibitory synapses, resulting in a more nuanced control mechanism.

The subthalamic nucleus (STN) is a part of the indirect pathway and acts as a crucial intermediary. It receives input from the globus pallidus and projects to the substantia nigra, further amplifying the inhibition of the thalamus.

GABA (gamma-aminobutyric acid) is the primary inhibitory neurotransmitter used in the basal ganglia. It plays a crucial role in inhibiting the thalamus and motor cortex, ensuring appropriate control of movement.

The lateral Globus Pallidus (GPL) is an output structure of the basal ganglia. It sends inhibitory signals to the thalamus and motor cortex, helping to refine and smooth movements.

Dopamine is a key neurotransmitter that plays a vital role in regulating movement. It is released in both the direct and indirect pathways, affecting the balance between movement facilitation and inhibition.

The Subthalamic Nucleus (STN), a key part of the indirect pathway, amplifies the inhibitory effect on movement by increasing inhibition of the thalamus.

The internal Globus Pallidus (GPi) is the final output structure of the indirect pathway, further inhibiting thalamocortical neurons, ultimately leading to decreased movement.

The hyperdirect pathway directly inhibits the motor thalamus and cortex using a high concentration of inhibitory neurotransmitters, causing a rapid suppression of ongoing motor activities. It acts like an 'emergency brake' for movement.

Schizophrenia-like psychosis can occur due to low dopamine in the mesocortical pathway or high dopamine levels in the mesolimbic pathway. Long-term use of dopamine antagonist antipsychotic drugs can also lead to problems like tardive dyskinesia and punding.

A type of movement disorder characterized by slow or fast, but discrete involuntary movements.