Cerebrum and Basal Nuclei Functions

The Cerebrum

• The cerebrum consists of the cortex, basal nuclei, and other structures.
• The basal nuclei are involved in initiating and terminating movements, suppressing unwanted movements, and regulating muscle tone.
• The basal nuclei are affected in diseases such as Parkinson's and Huntington's.

Histology of the Cerebrum

• The cerebrum has a layered structure, with the surface layer separated from the pia mater.
• The main type of neuron in the cortex is the pyramidal neuron, which releases glutamate and causes excitation.
• Interneurons, which release GABA and cause inhibition, are also found in the cortex.
• The networks of pyramidal neurons and interneurons regulate cortical function.

The Limbic System

• The limbic system is a functional system composed of parts of the cerebral cortex, diencephalon, and midbrain.
• The main regions of the limbic system include the amygdala, hippocampus, cingulate gyrus, and fornix.
• The limbic system is involved in emotions, memory, and motivation, and is often referred to as the "emotional brain".
• The limbic system is affected in mental illnesses such as Alzheimer's disease.

Alzheimer's Disease

• Alzheimer's disease is a neurodegenerative disease characterized by neuronal death, leading to dementia.
• The disease affects the cerebral cortex, hippocampus, and basal forebrain, leading to cognitive decline and memory loss.
• The brain shows dramatic shrinkage in the end stage of the disease, and there is no known cure or successful therapy.

Functional Anatomy of the Brain

• The nervous system has two divisions: the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS consists of the brain and spinal cord, while the PNS consists of all nervous tissue outside the CNS.
• The CNS includes the somatic nervous system (SNS), autonomic nervous system (ANS), and enteric nervous system (ENS).

The Human Brain

• The human brain is composed of approximately 100 billion neurons and 10 trillion neuroglia.
• The brain is responsible for emotions, solving equations, reading, and breathing, and is characterized by a high ratio of brain to body size.
• The frontal lobes of the brain are associated with higher executive functions such as self-control, planning, and abstract thought.

The Limbic System

• The limbic system is a ring of structures on the inner border of the cerebrum and floor of the diencephalon.
• The limbic system is responsible for emotions, memory, and motivation, and is connected to other brain regions.

Brain Diagram

• The brain diagram shows various structures, including the longitudinal fissure, septum pellucidum, internal capsule, insula, thalamus, subthalamic nucleus, hypothalamus, and cerebrum.
• The basal nuclei are located deep within the brain and are important for motor control, learning, and cognition.

Alzheimer's Disease (AD)

• Alzheimer's disease is a neurodegenerative disease characterized by neuronal death, leading to dementia.
• The disease affects the cerebral cortex, hippocampus, and basal forebrain, leading to cognitive decline and memory loss.
• The brain shows dramatic shrinkage in the end stage of the disease, and there is no known cure or successful therapy.

Pathological Features of AD

• Alzheimer's disease is characterized by the loss of neurons, particularly those that produce acetylcholine.
• The disease is also characterized by extracellular amyloid plaques and intraneuronal neurofibrillary tangles.
• The exact causes of Alzheimer's disease are still not fully understood.

Current Therapeutic Options for AD

• Current therapeutic options for Alzheimer's disease include replacing acetylcholine, which can help to improve cognitive function.
• Strategies to target beta-amyloid have failed so far.

Seizures and Epilepsy

• Seizures result from large groups of neurons being active together and discharging in high-frequency patterns.
• Epilepsy is the condition associated with the repeated occurrence of seizures.
• The causes of epilepsy include tumors, trauma, infection, vascular disease, and many unknown cases.

Drug Therapy in Epilepsy

• Current antiepileptic drugs act by three main mechanisms: reducing electrical excitability, enhancing GABA-mediated synaptic inhibition, and inhibiting T-type calcium channels.
• Newer drugs act by other mechanisms, largely yet to be elucidated.

The Major Antiepileptic Drugs

• The main drugs in current use are carbamazepine, phenytoin, valproate, ethosuximide, and benzodiazepines.
• If drugs do not work, surgical resection of the affected part of the cortex may be necessary.

Brain Organization

• The major parts of the adult brain are the cerebral cortex, basal ganglia, thalamus, hypothalamus, cerebellum, and brain stem.
• The cerebral cortex receives sensory information, sends messages to move skeletal muscles, integrates incoming and outgoing nerve impulses, and performs activities such as thinking, learning, and remembering.

The Cerebrum

• The cerebral cortex is the "seat of our intelligence" and is responsible for reading, writing, speaking, remembering, and planning.
• The cerebrum consists of an outer cerebral cortex, an internal region of cerebral white matter, and gray matter nuclei deep within the white matter.

Schizophrenia

• Schizophrenia is characterized by a loss of contact with reality, and a disruption of thought, perception, mood, and movement.
• The condition is a type of psychosis, and drugs used to treat it are called antipsychotics.

Schizophrenia: Drug Therapy

• Antipsychotic drugs, also known as neuroleptic drugs or major tranquillizers, are used to treat schizophrenia.
• These drugs are predominantly dopamine receptor antagonists, and may also act on other targets.

Pathophysiology of Schizophrenia

• The core features of schizophrenia include deficits in cognitive processes mediated by the circuitry of the dorsolateral prefrontal cortex.
• Alterations in dopamine, glutamate, and GABA neurotransmission are implicated in the disease.

Cerebrovascular Accidents (Stroke)

• Cerebrovascular accidents, or stroke, are sudden and severe losses of central nervous system function due to decreased blood flow to part of the brain.
• The functional consequence of a stroke is dependent on the part of the brain affected.

Stroke Management: Pharmacological

• Thrombolytic, anticoagulant, antiplatelet, and hypertensive therapies are used to manage stroke.
• Treatment of hyperlipidemia is also important.

This quiz covers the structure and functions of the cerebrum, including the basal nuclei and their roles in movement and muscle tone regulation.