🧢Neuroscience Unit 1 – Introduction to Neuroscience

Key Concepts and Terminology

• Neuroscience studies the nervous system, including the brain, spinal cord, and peripheral nerves
• Neurons are specialized cells that transmit electrical and chemical signals throughout the nervous system
• Glia are non-neuronal cells that support and protect neurons, including astrocytes, oligodendrocytes, and microglia
• Action potentials are electrical impulses that travel along the axon of a neuron, enabling communication between neurons
• Neurotransmitters are chemical messengers released by neurons at synapses to transmit signals to other neurons or target cells (muscles, glands)
• Synapses are specialized junctions between neurons where neurotransmitters are released and received
• Neuroplasticity refers to the brain's ability to change and adapt in response to experience, learning, and injury
• Neurodegenerative diseases involve the progressive loss of structure or function of neurons (Alzheimer's, Parkinson's)

Brain Structure and Function

• The brain is divided into three main regions: the forebrain, midbrain, and hindbrain
  • The forebrain includes the cerebrum, thalamus, and hypothalamus
  • The midbrain is involved in visual and auditory processing, as well as motor control
  • The hindbrain includes the cerebellum, pons, and medulla oblongata
• The cerebral cortex is the outermost layer of the cerebrum and is responsible for higher cognitive functions (perception, language, decision-making)
• The limbic system is a group of structures involved in emotion, memory, and motivation (hippocampus, amygdala)
• The basal ganglia are a group of subcortical nuclei involved in motor control, learning, and decision-making
• The cerebellum is responsible for coordinating movement, balance, and posture
• The brainstem connects the brain to the spinal cord and regulates vital functions (breathing, heart rate, sleep)
• The spinal cord transmits sensory and motor information between the brain and the body
• The peripheral nervous system consists of nerves that connect the central nervous system to the rest of the body

Neurons and Neural Communication

• Neurons consist of a cell body, dendrites, and an axon
  • The cell body contains the nucleus and other organelles necessary for cellular function
  • Dendrites are branched extensions that receive signals from other neurons
  • The axon is a long, thin extension that transmits signals to other neurons or target cells
• Neurons communicate through electrical and chemical signals
• Electrical signals, called action potentials, are generated when the neuron's membrane potential reaches a threshold
• Action potentials travel along the axon to the axon terminal, where they trigger the release of neurotransmitters
• Neurotransmitters diffuse across the synaptic cleft and bind to receptors on the postsynaptic neuron
• Binding of neurotransmitters can either excite or inhibit the postsynaptic neuron, depending on the type of receptor
• Neurons can be classified by their structure (unipolar, bipolar, multipolar) or function (sensory, motor, interneurons)

Neurotransmitters and Synapses

• Neurotransmitters are stored in vesicles at the axon terminal
• When an action potential reaches the axon terminal, it triggers the release of neurotransmitters into the synaptic cleft
• Common neurotransmitters include glutamate (excitatory), GABA (inhibitory), dopamine, serotonin, and acetylcholine
• Neurotransmitters bind to specific receptors on the postsynaptic neuron, causing ion channels to open or close
• Excitatory neurotransmitters (glutamate) cause the postsynaptic neuron to become more likely to fire an action potential
• Inhibitory neurotransmitters (GABA) cause the postsynaptic neuron to become less likely to fire an action potential
• Neurotransmitters are cleared from the synaptic cleft by reuptake or enzymatic degradation
• Synaptic plasticity refers to the ability of synapses to strengthen or weaken in response to activity (long-term potentiation, long-term depression)

Neuroplasticity and Learning

• Neuroplasticity enables the brain to adapt and change throughout life in response to experience, learning, and injury
• Synaptic plasticity is a key mechanism underlying learning and memory
  • Long-term potentiation (LTP) strengthens synaptic connections between neurons that fire together repeatedly
  • Long-term depression (LTD) weakens synaptic connections between neurons that do not fire together
• Structural plasticity involves changes in the number and structure of neurons and synapses (neurogenesis, synaptogenesis)
• Critical periods are developmental windows during which the brain is particularly sensitive to specific experiences (language acquisition, visual development)
• Neuroplasticity can be harnessed for rehabilitation after brain injury or stroke
• Enriched environments and mental stimulation can promote neuroplasticity and cognitive function throughout life

Research Methods in Neuroscience

• Neuroscientists use a variety of techniques to study the structure and function of the nervous system
• Neuroimaging techniques allow researchers to visualize brain activity and structure non-invasively
  • Functional magnetic resonance imaging (fMRI) measures changes in blood flow related to neural activity
  • Electroencephalography (EEG) records electrical activity in the brain using electrodes placed on the scalp
  • Positron emission tomography (PET) uses radioactive tracers to measure metabolic activity or neurotransmitter levels
• Electrophysiology techniques record electrical activity from individual neurons or groups of neurons (patch-clamp, extracellular recording)
• Optogenetics uses light-sensitive proteins to control the activity of specific neurons in living organisms
• Animal models are used to study the nervous system and test potential treatments for neurological disorders (rodents, primates)
• Post-mortem studies examine brain tissue from deceased individuals to investigate structural changes or pathology
• Computational modeling simulates neural networks and brain function using mathematical algorithms

Disorders and Treatments

• Neurological disorders result from damage to or dysfunction of the nervous system
• Neurodegenerative diseases involve the progressive loss of neurons and include Alzheimer's, Parkinson's, and Huntington's disease
• Psychiatric disorders, such as depression, anxiety, and schizophrenia, involve changes in brain chemistry and function
• Neurodevelopmental disorders, like autism and attention-deficit/hyperactivity disorder (ADHD), affect brain development and behavior
• Traumatic brain injury (TBI) results from a sudden, external force to the head and can cause a range of cognitive and behavioral impairments
• Stroke occurs when blood flow to the brain is disrupted, leading to cell death and neurological deficits
• Treatments for neurological disorders may include medications, surgery, rehabilitation, and neuromodulation techniques (deep brain stimulation)
• Gene therapy and stem cell therapy are emerging approaches that aim to replace or repair damaged neurons

Emerging Trends and Future Directions

• Advances in neuroimaging and computational methods are enabling more detailed studies of brain structure and function
• Big data and machine learning approaches are being used to analyze large datasets and identify patterns in neural activity and behavior
• The Human Connectome Project aims to map the complete network of neural connections in the human brain
• Optogenetics and chemogenetics are providing new tools for precise control of neural circuits in animal models
• Neuroengineering involves the development of brain-computer interfaces and neural prosthetics to restore function after injury or disease
• Research on the gut-brain axis is revealing the complex interactions between the digestive system, microbiome, and brain function
• The study of sleep and circadian rhythms is providing insights into the role of sleep in brain health and disease
• Personalized medicine approaches aim to tailor treatments to an individual's unique genetic and neurological profile