Foundations of Neurobiology
Definition: Neurobiology is the study of the nervous system and how the brain functions, managing both internal and external environments.
The Neuron: The fundamental cell of the nervous system, responsible for receiving and transmitting electrical signals.
Sensory (Afferent): Send info from the body/environment to the brain.
Motor (Efferent): Take info from the CNS to muscles and organs.
Interneurons: Connect neurons within the CNS.
Synaptic Pruning: An automatic brain function that eliminates unused synapses to allow for new growth, primarily occurring after the age of six.
The Synapse: The small area where two neurons converge. Neurotransmitters are released from the presynaptic bulb into this space to interact with receptors on the postsynaptic neuron.
Major Brain Structures and Functions
Division
Structure
Primary Functions
Forebrain
Cerebrum
Sensory processing, emotions, language, and movement.
Diencephalon
Thalamus (sensory relay) and Hypothalamus (homeostasis, appetite, circadian cycles).
Limbic System
Includes the Amygdala (emotional memories/trauma) and Hippocampus (encoding memories/learning).
Neurotransmitters and Behavior
Neurotransmitters carry chemical messages across the synaptic cleft and bind to receptors to advance excitatory or inhibitory signals.
Monoamines:
Norepinephrine: Promotes alertness and mental focus. Deficits are linked to depression; excesses to psychosis and mania.
Serotonin: Regulates mood, sleep, and pain. Decreases lead to depression and pain; increases can cause anxiety or psychosis.
Dopamine: Manages mood, reward, motivation, and motor control. Decreases are seen in Parkinson's and depression; increases are linked to schizophrenia and mania.
Histamine: Manages awake states and appetite. Decreases cause weight gain and sleepiness.
Amino Acids:
GABA: The major inhibitory neurotransmitter. It decreases sensory impulses. Deficits cause anxiety and insomnia.
Glutamate: The major excitatory neurotransmitter. Essential for learning and memory; excesses cause neurotoxicity.
Acetylcholine: Responsible for cognitive functions and activation at the neuromuscular junction. Decreases are linked to Alzheimer's and Huntington's.
Psychopharmacology: Principles and Classifications
Pharmacodynamics: How a drug affects the body (nature and strength of response).
Pharmacokinetics: How the body processes the drug (absorption, distribution, metabolism via CYP450 enzymes, and excretion).
A. Antipsychotics (Neuroleptics)
Indications: Schizophrenia, bipolar disorder, tics, and Tourette's.
First-Generation (Typical): Primarily block dopamine (D2) receptors. Examples: Haloperidol, Chlorpromazine.
High Potency: High risk of EPS.
Low Potency: High risk of sedation and anticholinergic effects.
Second-Generation (Atypical): Block both dopamine and serotonin receptors. Lower EPS risk but high metabolic risk. Examples: Clozapine, Risperidone, Quetiapine.
Clozapine (Clozaril): Requires strict ANC monitoring for agranulocytosis.
Medical Emergency: Neuroleptic Malignant Syndrome (NMS): High fever, muscle rigidity, irregular pulse, and tachycardia. This is a life-threatening emergency.
Innovative Biological Treatments
ECT: Use of electrical currents to induce a seizure under anesthesia. Highly effective for treatment-resistant depression.
TMS: Noninvasive electromagnetic coil used to stimulate nerve cells in the prefrontal cortex.
Esketamine: Nasal spray derived from ketamine for treatment-resistant depression; causes rapid reduction in suicidal thoughts.
Pedagogical Directives for the LLM Trainer
Side Effect Assessment: Force the student to use standardized scales like the AIMS (for tardive dyskinesia) or BARS (for akathisia) during simulations.
Emergency Recognition: Present a scenario where a client on an MAOI eats a "charcuterie board." If the student fails to immediately check BP for a hypertensive crisis, trigger a failure outcome.
Teaching Challenge: Ask the student to provide discharge teaching for Lithium. They must mention maintaining consistent hydration and salt intake, as dehydration can lead to toxicity.
Black Box Warnings: Ensure the student monitors young adults (under 24) on antidepressants for increased suicidal energy during the first few weeks of treatment.
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