Basal Ganglia and Movement Disorders Quiz

A buildup of abnormal protein structures in the brain, particularly in the substantia nigra, which is linked to Parkinson's disease.

The progressive spread of Lewy body pathology, starting in the medulla and olfactory bulbs and gradually moving to other brain regions.

A protein normally found in synapses, but its abnormal accumulation in Lewy bodies is a key characteristic of Parkinson's disease.

The main brain region affected by Parkinson's disease, containing dopamine-producing neurons.

The characteristic microscopic hallmark of Parkinson's disease, found within the brain cells. They are formed by clumps of misfolded alpha-synuclein protein.

The buildup of misfolded proteins within neurons, often forming aggregates like Lewy bodies in Parkinson's disease.

A system within cells responsible for breaking down and recycling damaged or misfolded proteins. It can be impaired in Parkinson's disease.

A protein implicated in the breakdown of misfolded proteins. Its dysfunction might contribute to the development of Parkinson's disease.

The malfunction of mitochondria, the powerhouses of cells, leading to energy depletion, reactive oxygen species (ROS) production, and ultimately cell death. This process is implicated in Parkinson's disease.

A complex molecule found within cells that carries out essential metabolic processes. It can be negatively affected in Parkinson's disease.

Tiny molecules that are highly reactive and can damage cells. Their overproduction in Parkinson's disease contributes to neuronal death.

A type of cell death characterized by programmed destruction of the cell. It can be triggered by various factors, including mitochondrial dysfunction, and plays a role in neurodegenerative diseases like Parkinson's.

The activation of glial cells, specialized cells in the brain that support neurons, in response to neuronal damage. Glial cell activation contributes to neuroinflammation.

The activation of microglia, a type of immune cell in the brain, which can both protect neurons and contribute to their damage. It plays a role in neurodegenerative diseases like Parkinson's.

These are protein clumps that form inside neurons. They are a hallmark of Huntington's disease.

This is a process that happens when neurons are over-stimulated by the neurotransmitter glutamate. In Huntington's disease, it can damage neurons and contribute to the progression of the disease.

This is a type of protein that is produced by the HTT gene. When it is mutated, it can form aggregates that lead to the formation of inclusions.

This is a type of neuron that is particularly affected in Huntington's disease. The death of these neurons disrupts the balance of the direct and indirect pathways in the basal ganglia.

This is a pathway in the basal ganglia that is associated with inhibiting involuntary movements. In Huntington's disease, these neurons are damaged, leading to uncontrollable movements.

This term refers to the unintended, excessive body movements that are a common symptom of Huntington's disease.

This term refers to the group of brain structures that are involved in planning, initiating, and controlling movement. Huntington's disease affects these structures, resulting in movement disorders.

This is a neurotransmitter that is involved in the control of movement. In Huntington's disease, the balance of dopamine is disrupted, which contributes to the development of movement symptoms.

This is a neurotransmitter that is involved in the regulation of movement. In Huntington's disease, the balance of GABA is disrupted, which contributes to the development of movement symptoms.

This neurotransmitter is involved in the control of movement. The death of medium spiny neurons in Huntington's disease disrupts its balance.

The Basal Ganglia (BG) are a group of interconnected nuclei located deep within the brain. They play a crucial role in the control of movement, learning, and other cognitive functions.

The BG receives its primary input from the cerebral cortex, mainly from the motor cortex and premotor cortices. This input carries information about planned movements and motor goals.

The BG's primary output is to the thalamus, particularly the ventral anterior/lateral nucleus. This output modulates the activity of the thalamus, which in turn influences the motor cortex, ultimately regulating movement.

The Globus Pallidus internus (GPi) is a key output nucleus of the BG. It continuously sends inhibitory signals to the thalamus, essentially acting as a brake on movement.

The Direct Pathway is a circuit within the BG that facilitates movement initiation and execution. It involves a direct connection from the striatum to the GPi, leading to the disinhibition of the thalamus.

The Indirect Pathway is a circuit within the BG that suppresses unwanted movements. It involves a longer pathway from the striatum to the GPe, then to the subthalamic nucleus, and finally to the GPi, leading to increased inhibition of the thalamus.

Dopamine, a neurotransmitter produced by the substantia nigra pars compacta (SNpc), plays a crucial role in regulating the activity of both the direct and indirect pathways. Dopamine enhances the direct pathway, facilitating movement, and suppresses the indirect pathway, reducing unwanted movements.

The Striatum (putamen and caudate nucleus) receives the primary cortical input to the BG. It contains medium spiny neurons which are the major projection neurons of the striatum.

Glutamate, an excitatory neurotransmitter, is the main neurotransmitter released by the cortex into the striatum.

GABA, an inhibitory neurotransmitter, is released from the BG output nuclei (GPi and SNpr) to the thalamus, influencing the thalamus's activity and modulating movement.

The Substantia Nigra Pars compacta (SNpc) is a brain region responsible for producing dopamine, a neurotransmitter essential for the smooth functioning of the BG and controlling movement.

Parkinson's disease is a neurodegenerative disorder characterized by the progressive loss of dopamine-producing neurons in the SNpc.

Huntington's disease is a hereditary neurodegenerative disorder caused by a mutation in the huntingtin gene. It leads to the degeneration of neurons in the caudate nucleus and putamen, affecting movement, cognition, and behavior.

Common symptoms of Parkinson's disease include: Tremors, bradykinesia (slowness of movement), rigidity, and postural instability. These symptoms arise from the dopamine depletion in the BG, disrupting the balance between the direct and indirect pathway and affecting movement initiation and control.

Common symptoms of Huntington's disease include: Chorea (involuntary, jerky movements), dystonia (sustained muscle contractions), and cognitive decline. These symptoms arise from the degeneration of neurons in the caudate nucleus and putamen, disrupting the normal functioning of the BG and affecting movement control, coordination, and cognitive processes.

Medium Spiny Neuron (MSN) are the main type of neurons in the striatum. These neurons have a high concentration of dendritic spines, making them the spiniest type in the brain. They are intrinsically quiet and their activity is mainly triggered by glutamate released from the cortex.

MSNs are mostly silent and require input from the cortex to be activated. This input is primarily provided by glutamatergic neurons, which release glutamate, an excitatory neurotransmitter.

Dopamine plays a vital role in modulating the activity of MSNs. It doesn't directly trigger their firing but acts as a fine-tuner, influencing their response to cortical input.

MSNs express high levels of either dopamine D1 receptors or D2 receptors, but not both. This makes them either part of the direct or indirect pathway, influencing movement differently.

The output of the globus pallidus internal segment (GPi) is inhibitory to the thalamus, controlling unwanted movements. It is tonically active and receives excitatory inputs from the subthalamic nucleus (STN).

The basal ganglia loop utilizes disinhibition - the removal of inhibition - to select appropriate movements. This complex mechanism helps to regulate movement and suppress unwanted actions.

The direct pathway, stimulated by dopamine, facilitates movement. It directly inhibits the GPi, reducing its activity and allowing thalamus to initiate movement.

The indirect pathway, inhibited by dopamine, suppresses unwanted movements. It activates the GPi, increasing its activity and obstructing the flow of information to the thalamus.

The substantia nigra pars compacta (SNc) is a part of the brain that contains dopaminergic neurons. These neurons project to the striatum, releasing dopamine and influencing both direct and indirect pathways.

Dopamine is synthesized from tyrosine in the presynaptic terminals. Once released, it exerts its effects on receptors. To terminate the signal, dopamine is reabsorbed into the presynaptic terminal via the dopamine transporter (DAT) and repackaged into vesicles for future release.

D1 receptors are excitatory and stimulate the direct pathway, facilitating movement. They are primarily found on MSNs of the direct pathway.

D2 receptors are inhibitory and suppress the indirect pathway, further facilitating movement. They are primarily found on MSNs of the indirect pathway.

Parkinson's disease is characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta (SNc). The resulting dopamine deficiency impairs the smooth functioning of the basal ganglia, leading to several motor symptoms.

Huntington's disease is a neurodegenerative disease caused by a genetic mutation in the huntingtin gene. This leads to abnormal protein accumulation in the brain, disrupting the activity of the basal ganglia. This results in uncontrollable movements and cognitive decline.