Neuroscience and Nervous System Connections Expanded Notes

Neuronal Connections

• Neuron connections are known as synapses.

• Dendrites and axons are vital for communication within the nervous system.

• Dendrites: Graded potentials (short distance, short duration)

• Axons: Action potentials (long distance, long duration)

Potentials can be classified based on their role in neuronal communication, with graded potentials serving to receive signals and action potentials serving to transmit these signals across distances.

• Graded Potential:

• Initiated by chemical-gated ion channels.

• Requires a ligand (chemical) to open the channel.

• Action Potential:

• Initiated by voltage-gated ion channels.

Types of Synaptic Connections

• Axodendritic: Axon from one neuron attaches to dendrites of another neuron.

• Axosomatic: Axon from one neuron attaches to the cell body (soma) of another.

• Axoaxonic: One axon connects to another axon.

• Neurons typically have one axon.

• Dendrodendritic: Connection between dendrites of two neurons.

• Somatodendritic: Cell body of one neuron attaches to dendrite of another.

Central vs. Peripheral Nervous System

• Neurons are interconnected, which provides structure for the brain and spinal cord.

• Misconception: We only use 30%-50% of our brain; research shows we use 100%.

Brain Structure

• The brain and spinal cord function as a continuous organ, their anatomy can mislead to believe they are separate.

• Brain has various parts not fully understood by scientists (e.g., insula).

Grant and Publishing Process

• Research must be peer-reviewed before publication.

• Different academic levels (bachelor's, master's, doctorate) signify eligibility to review studies.

Types of Synapses

• Chemical Synapse: Involves neurotransmitter release.

• Electrical Synapse: Direct electrical connection between cells.

Neurons and Axon Functionality

• Axo-Somatic Connections:

• Connect axon terminals to neuron cell body (soma), vital for information processing.

• Can collect or release information (e.g., neurotransmitters).

• Axo-Dendritic Connections:

• Connect axon terminals to dendrites, crucial for information intake.

• Axo-Axon Connections:

• Connections between axons from different neurons; involves only two different axons.

Philosophy of Brain Functionality

• Majority of the nervous system is reliable but still has uncertainties.

• Up-to-date information is crucial as neuroscience evolves rapidly.

Infection Paradigm

• Axons can collect pathogens retrograde, leading to diseases like polio (still present despite vaccination misconceptions).

• Measles resurgence due to vaccination gaps.

Cerebral Lobes

• Five lobes each hemisphere: Insular, Frontal, Parietal, Occipital, Temporal.

Speech Areas of the Brain

• Broca's Area: Controls motor functions involved in speech production.

• Wernicke's Area: Responsible for language comprehension.

Diencephalon

• Contains major connections between brain hemispheres:

• Corpus Callosum: Largest connection, integrative function.

• Anterior and Posterior Commissure: Smaller connections.

• Thalamus: Sensory relay center, decides on memory function.

• Hypothalamus: Controls endocrine functions, hunger, sleep, hormonal release.

• Links to the pituitary gland via infundibulum.

• Pituitary Gland: Stores hormones for various bodily functions, small structure, crucial for hormone synthesis and release.