Behavioral Neuro (fixed)

Structure of the Vertebrate Nervous System 

  • Neuro anatomy is the sutydy of the structure or organization of the nervous system  

  • This field of study largely relies on a localizationist approach  

  • Neuroanatomy contains differenet levels of analysis from gross to cellular level   

 

Important Terminology 

Rostral-> towards  

Caudal-> away  

 

Pereipheral nervous system- somatic and autonomic nervous system  

CNS- brain and spinal cord 

  

 

 

 

 

PNS is everyhting but the brain and spinal cord  

 

Divisions of the NS  

Somatic 

  • Contains all axons conveying messages from the skin or beneath the skin, tactile info, pain signals 

  • Motor neurons  

  • Axons that project out to the muscles 

Autonomic  

  • Maintaining homeostasis  

  • Heart rate  

  • Blood pressure  

  • Connects to alot of cognitize and emotional process but communicates with brain mostly  

  • Diff arangement of neurons that give us idea of how the system works  

Divided into 2 seperate system 

  • Parasympathetic  

  • Maintanence of body while resting 

  • Long preganglionic acid  

  • Ganglia sit near or within the arget organs so the preganglionic axons are long and post ganglionic axons re short  

  • acetylcholine 

  • Sympathetic 

  • Fight or flight system  

  • norepinephrine 

Ganglion 

  • Cluster of neurons in the PNS 

 

 

 

Central Nervous System  

Spinal cord  

  • Dorsal root ganglion  

  • Brings sensory info  

  • Into the cns via dorsal horn  

  • Butterfly is the grey matter  

  • a butterfly- or "H"-shaped inner region made of nerve cell bodies, unmyelinated axons, dendrites, and glial cells 

  • Everythng else is white matter  

  • the outer tissue layer composed of myelinated nerve fiber bundles (tracts) that relay sensory and motor signals between the body and the brain 

  • Sensory comes in through Dorsal side 

  • Motor comes out through ventral side 

  • Ganglion  

  • Bunches of neruonal cell bodies all together outside the CNS  

  • Call GANGLION NUCLEUS IN CNS 

  • Segmentation  

  • Each section of the spinal cord sends signals toi a specific part of your body  

  • Lower back to legs  

  • Dr shenai patients 

  • Mid chest to mid back and so on and so forth  

More terms  

  • Central canal  

  • A fluid filled channel of the spinal cord  

  • Ventricles  

  • Are four fluid filled cagaties within the brain containing cerebrospinal fluid 

  • CSF  

  • Clear fluid in the brain and spinal cord  

  • Provides cushioning for the brain  

  • Also is a resevoir of hormones and nutrition for the brain+ spinal cord  

  • Meninges  

  • Membranes that surround the brain and spinal cord  

Dura Mater  

  • Drua mater outermost thick skin like later  

  • Thick  

  • Gross 

  • Super difficult to cut through  

Arachnoid Space 

  • Contains blood cells and CSF  

  •  

Pia Mater  

  • Innermost thinner layer  

  • Right on top of brain  

  • Super thin  

 

 

 

PAD  

  • P 

  • Pia Mater  

  • A 

  • Arachnoid Space 

  • D 

  • Dura Mater 

 

 

 

 

Major Divisions of the Brain  

Three Major  

  • Forebrain  

  • Diencephalon  

  • Hypothalamus  

  • Small area near the base of the forebrain  

  • Converys messages to the pituatary gladn to control endocrine function  

  • Also has neural projections to many brain regions  

  • Motivated behaviors eating drinking reproduction defensive etc  

  • Pituitary gland  

  • Hormone producing gland found at the base of and controleld by the hypothalamus  

  • Thalamus  

  • Serves as a intermdiary between sonsorimotor cortex  

  • We often refer to the thalamus as a relay betweeen cortex and subcortical systems but a lot of evidence shows that t is a key structure in information processing  

  • Telencephalon 

  • Basal Ganglia  

  • Comprised of caudate nucleus  

  • Putamen  

  • Globus pallidus  

  • Associated with voluntary movement procedual learning  

  • Loss of function of basal ganglia is what we see with PD  

  • Procedural learning  

  • Limbic System  

  • Most of the limbic system is contained within the telencephalon except the hypothalamus  

  • Comes from latin term meaning border  

  • Everything that makes up the limbic system are on the border of stuff  

  • Olfactory bulb  

  • Hippocampus  

  • Amygdala  

  • Hypothalamus kinda  

  • Cingulate gyrus of the cerrebral cortex  

  • Really important for emotion and motivation and long term memory  

  • Midbrain  

  • Mesencephalon  

  • Compared ot other parts of the brain the midbrain is quite small  

  • Superior and inferior Collicullus (2 for each side of the brain)- 

  • Appear as bumps  

  • On the top suface of the midbrain  

  • The colliculi are important for orienting to visual and auditory stimuli  

  • Together they are talked about as tectum  

  • Hindbrain 

  • MEdulla 

  • Brain stem  

  • Located superior to spinal cord  

  • Responsible for vital reflexes such as breathing  

  • Hreart rate 

  • Vomitiing  

  • Salivation  

  • Coughing  

  • Sneezing  

  • Cranial nerves  

  • Brain equivailent to peripehral nerves 

  • Obviously alot of muscles in neck and head which have to receive sensory info and to control motor info  

  • Controlling toungue movement  

  • Movement of eyes  

  • 12 crainial nerves 

  • I  

  • Olfactory nerve 

  • Smell 

  • II 

  • Optic nerve  

  • Back of each eye to brain 

  • VIIII 

  • Auditory nerve 

  • Conveys sensory info needed for hearing  

  • X 

  • Vagus  

  • Info from internal organs  

  • Critically important for controlling parasympathetic nevous system  

  • Sensory+ motor components  

  • Cerebellum  

  • A structure located deep in the hindbrain with many deep folds  

  • Helps regulate motor movement  

  • Balance and coordinaiton  

  • Important for shifting attention between auditory and visual stimuli  

  • Pons  

  • Latin for bridge  

  • contains structures important for sleep wake regulation  





 

 

Neuronal types were originally defined by their shape  

  • Also, can be described by number of poles on cell body: uni-, bi-, and multipolar 

  • Multipolar 

  • Stellate  

  • Fusiform  

  • Pyramidal  

  • Classificiation is more based on molecular composition but we still use these terms 

 

neuron 

  • Input zone  

  • dendrites 

  • Integration zone  

  • Between cell body and axon 

  • Conducting zone 

  • Axon 

  • Output zone 

  • Axon terminal  

 

What makes them differnet  

  • Structural Differences 

  • Unipolar (or pseudo-unipolar) neurons: Have a single process extending from the cell body that splits into two branches—one acting as a dendrite and the other as an axon.  

  • Bipolar neurons: Have two distinct processes attached to opposite sides of the cell body: one single dendrite and one single axon.  

  • Multipolar neurons: Have three or more processes coming off the cell body, consisting of one single axon and multiple branching dendrites.  

 

Types Neuron  

  • Multipolar 

  • Pyramidal  

  • Cellbody in the middle 

  • Dendrites coming from corners of a pyramid  and top  

  • Axon is coming off of the base  

  • Fusiform  

  • 2 dendrite branches  

  • Common brain cell type  

  • Stellate  

  • Star shaped  

  • Processes coming off each end plus axon obv 

  • Unipolar 

  • Sensory Neuron 

  • A sensory neuron is specialized at one end ot be highly sensitive to a particular type of stimulation  

  • Bi polar  

  • Motor neuron  

  • Has its soma in the sinal cord and receives exicitation from other neurons and conducts impulses along its axon to a muscle.  

 

Dendrites and Spines  

  • Dendrites  

  • Are the branching fibers lined with snuyaptic receptors that recieve info from other neurons  

  • Contain dendrititic spines  

  • Which are tiny protuberances prividing sites for postsynaptic contact  

  • “highly plastic” 

  • Allows rapid changes in connectiviity following environmental experience  

  • As in neuroplasticitiy  

Cell body  

  • Cell body  

  • Soma  

  • Perikaryon  

  • Contians the nucleus, mitochondria, ribosomes, and other structures found in other cells  

  • More thinking of it as performing cells n   

  • Translation of MRNA into proteins  

 

Axon  

  • Axon 

  • Thin fiber responsible for transmitting nerve impulses toward other neurons, organs or muscle  

  • Could be longer than three feet, axon in you leg go from the back.  

  • Neurons only have one axon but it may branch many times  

  • Bifurcate 

  • Branching off  

  • They do this to try to send signals in different directions  

  • Presynaptic terminals or boutons 

  • They have an insulating material called myelin sheath 

  • It is a complicated lipid structure 

  • Helps improve electrical efficiency  

  • Everything that connects to spinal cord is myelinated  

  • Nodes of Ranvier  

  • allow rapid and efficient propagation of nerve impulses along myelinated axons via saltatory conduction 

  • Relationship of neurons  

  • Afferent axon 

  • Refers to bringing info toward a structure  

  • A- arriving too  

  • Efferent  

  • Refers to carrying info away from a structure 

  • E- Exiting  

  • Inter neurons  

  • Neurons with dendrites and axons that are completely contained within a single structure  

  • Fucutional divbisions of a neuron  

  1. Input zone  

  1. Mostly dendrites, some cell body, part of the neuron that contians all info that is coming in  

  1. Integration zone  

  1. Axon hillock  

  1. Cell body area where all incoming info into the neuron is combined to determine whether or not to send a signal of its own  

  1. Specialized part of axon where “decision is made” 

  1. Axon hillock 

  1. The “decision” is made at integration zone  

  1. Conduction zone  

  1. Part of axon where the electirical impulse will travel  

  1. Output zone  

  1. Outputs  

 

Synapse 

Pre Synapse 

  • Space between the azon erminal/ button and the postsynaptic membranes of two neurons  

  • Active zone  

  • Region in the presynaptic button that regulates release of chemicals called neurotransmitters for communication with the  neuron on the post synaptic side  

  • Where the synaptic veisicles are located  

  • Where the neurotransmitters are sitting  

  • Neurotransmitters are specialezed chemical substances that are used to communicate with the post-synaptic neuron  

  • The synapse is not a tight fit  

  • Pause 

  • Receptors  

  • Specialized proteins that capture and react when the neurotransmitter binds n   

Post synaptic side 

  • Post synaptic Density  

  • They are separate but info can be rapidly transferred  

  • Protein dense network attached to the postsynaptic membrane  

  • Contains like 1k proteins or more  

  • This complexity is what makes synapses modifiable which we’ll return to with learning and memory  

How to view neurons  

  • Light microscopy  

  • Shows cells and their processes using staining methods  

  • This is what Golgi and Cajal had  

  • Stained the cells  

  • Shined light over it  

  • Looked through light microscope  

  • Electron microscopy  

  • Also using staining  

  • Mid 1900’s  

  • Shine electrons on your sample  

  • Makes it much higher resolution  

  • Shows synapses and organelles  

  • Fluorescence and confocal microscopy  

  • Light based as well  

  • But allows researcher to label specific cells of insttreat  

Other Cells in the NS 

  • Glia  

  • Other major components of the nervous system that exchange chemicals with adjacent neurons 

  • NS is 50% glial cells  

  • 1:1 in the brain  

  • Astrocytes  

  • Start chaped cells with numerous processes that extend in all direction  

  • They can attach to neurons and blood vessels to regulate local blood flow and provide support to neurons  

  • Astrocytes also participates in synaptic communicatin by having processes connecting nearby to the synapse 

  • Seems like they are communicationg between vasculatur and neurons  

  • Also involved in the formation of synapses and pruning of excess oens during development  

  • Micro Glia  

  • These cells extend  

  • Kinda looks like astrocytes  

  • Activated in response to injury  

  • By growing and changing shape  

  • Resident immune cell for nervous system  

  • LIVE IN NS 

  • They can form an area of containment around a site of damage and remove and destroy debris  

  • Microglia are sometimes called the immune cells of the brain and spinal cord  

  • Have roles in normal synapse formation and elimination   

  • Oligodendrocytes  

  • Central nervous system, build myelin  

  • Schwann Cells  

  • Peripheral 

  •  build the myelin sheath that surrounds axons of neurons  

  • Radial glia  

  • Guide the migration of neurons and the growth of their axons and dendrites during brain development and occasionally, during adulthood.  

Blood Brian Barrier (BBB) 

  • This is why the brian and spinal cord are compartmnetalized form the rest of hte body  

  • Specialized barrier that limits info from blood stream, can be brought ot the brian  

  • Not a real barrier  

  • Provides an important layer of defense against invader 

  • Virii  

  • Bacteria  

  • Harmful stuff  

  • Brain is a spnge and holes in the brain is blood  

  • BBB covers all vasculature to prevnet signals from blood to difuse into the brain  

  • BBB has two layers 

  • Endothelial cells that prvent diffusion in and out of blood vessels  

  • Astrocytes that wrap around and support the endthelial cells  

  • How can chemical pass through the BBB 

  • Passive transport  

  • When they r in blood stream, they can just diffuse freely  

  • Anything in the blood that is lipid soluble can diffuse through BBB 

  • Like  

  • ALC  

  • THC 

  • O2  

  • CO2 

  • Hormes such as 

  • Test  

  • Estrogen  

  • Active transport 

  • Means that the substances across  

  • And is more tightly regulated  

  • Amino acids  

  • Glucose  





The mind brain relationship 

  • Dualism  

  • The belief that there are diff kinds of substance that exist independently  

  • The non material soul is seperate from the mind and the body  

  • Monism 

  • The belief that the universe is only comprised of one type of substance  

  • Forms 

  • Materials- everything that exists is physical by nature  

  • Mentalism- physical and psychological phenomena are mentally constructed and are therefore only explicable in terms of the mind  

  • Identity position  

  •  mental processes and brain processes are the same but described in different terms 

  • No feeling i can have is in absence of brain activity  

  • Solves problem of mind brain rls 

  • Brain functioning can be explained at a fundamental level in terms of neuronal and glial cell activity  

  • Neuron 

  • Primary cell in brain that communicate  

  • Glial cells  

  • Non neuronal support cells in the central and peripheral nervous systems that protect, insulate, and nourish neuron 

 

A brief history of brain research and the origins of Neuroscience 

  • Localization theory  

  • Different parts of the brain serve different functions  

  • Structures which look the same/diff should have same/diff functions  

  • mostly recognized 

  • Holism  

  • Brian function is not localized instead, function is distributed more homogenously throughout  

  • Motor functions are not localized to one area, carried out by the entire brain or a large part of the brain so much so you are unable to pinpoint 

  • Holism is a neuro term 1800’s  

Looking at the brain  

  • Top – dorsal surface 

  • Bottom- ventral surface 

Brief (Eurocentric) history of brain research  

  • BCE 

  • Aristotle, Hippocrates, Plato, 

  • Liver heart not as much brain  

  • Mental processes come from other parts of the body, less of the brain  

  • 200 AD 

  • Galen- surgeon from roman times  

  • Documented hundreds of cases of people that he treated iin the military  

  • Interesting form clinical standpoint  

  • All diff types of head injuries  

  • Swords and all that bs  

  • One of the first people to recognize connection between head and brain injury and neurological impairment  

  • Thought it was from the ventricles 

  • Ventricles  

  • Hollow fluid filled areas of the brain  

  • Filled with CSF 

  • This is waht they believed  

  • Lateral ventricle  

  • Sensory sutff 

  • Middle  

  • Fantasy ideation cognition  

  •  

  • 1500s 

  • Da vinci and vesalius 

  • Also thought it was the ventricles  

 

  • 1600s 

  • Thomas willis  

  • Proposed tat cerebreal hemisphered controlled memory and will  

  • Imagition was tied to cerebral hemisphres 

  • brain material was also implicated in sensation and movement 

  • -cerebellum and brain stem were more involved in vital and 

  • involuntary systems 

  • Descartes  

  • Proponent of dualism  

  • Some of the functions that the brian was carrying out was mechanical in nature  

  • Reflexive machine (brain was) 

Rise of localization  

  • Legallois (1770-1840) 

  • Isolated a part of the respiratory center, to a specific part of the brain stem  

  • V important finding  

  • Bell magendie law 

  • Dorsal spinal nerves root contains only sensory fibers, and ventral spinal roots contain only motor fibers  

  • Led to rise of localitionist prospective  

  • Previosly sensory and motor signals were believed to be mized  

  • Bell first hypothesiszed this functional disticition in the spoinal cord 

  • Magendie provided definitive support for this idea 

  • Phrenology  

  • Franz joesph gall  

  • Put the idea of coritcal localization into play  

  • 1809 formulated phrenology idea that skull features were indicative of brain development such that specific faculties could be detected by surface features  

  • Although initially popular  

  • Idea behind it  

  • Features of the skulls surface  

  • Deformities and differences  

  • Predicts feelings and genes 

  • Because every skull looks different  

  • The brian looked differnent under it  

  • Ends up getting discredidted  

  • Holism fills the vacuum  

  • Flourents  

  • Galls leading critic  

  • Worked on birds 

  • Thought it was how much brian he removed not where  

  • Paul Broca 

  • Brocas area  

  • 1861 

  • Was the first to provide definitive proof of cortical localization not based on skull surface features  

  • Examined case of monsieur Leborngne who had inability to form speech  

  • Leborgne died  

  • And upon postmortem analysis revealed specific damage to a relativley discrete portion of the inferior frontal gyrus  

  • Another dude pulled up  

  • Had deadass the same issue  

  • Broca looked at both of their issues  

  • Realized there was a specific lesion in the frontal cortex of both men  

  • Localized in the left hemisphere  

  • Motor Cortex discovered in monkey (humans) 

  • Fritz and Hitzig 1870 

The neuron doctrine  

  • Started with development of cell theory in 1800s  

  • Most scientists thought that branches of nerve cells formed a continuous net, sometimes called the nerve net theory, and this view also was used against the idea of cortical localization  

  • Theodore Schwann 1810-1872 

  • First to propose neuron doctrine in 1839 

  • That the entire body including the nervous system was made up of individual cells  

  • Camillo golgi (1840-1926) 

  • Developed a silver staining procedure that allowed for visualizing occasional cells  

  • Golgi Staining 

  • Santiago Ramon y Cajal 1852-1934 

  • Began to work with silver stains and made significant technical improvements to the method  

  • Cajal amassed a massive archive of anatomical data describing neuron structure  

  • Cajals Neuron doctine  

  • Revealed cells  

  • Werent just connected in web like manner,  

  • Cells were dicontinuous  

  • Starting and ending points  

  • Over time his discoveries became widely accepted  

  • Cajals work also privded considerable insight into the cell and brian function  

  • Cajal is goatmaxxing  

  • Used golgi stain to look at diff cell layers in cortex 

  • Cut gyrus (ridges of cortex) 

  • Used golgi staining  

  • Visual cortex  

  • Motor cortex  

  • Layering patterns were diff in both  

  • Korbinian Brodmann 1909 

  • Looked at cellular features of all major areas of the cortex  

  • Basiclaly said  

  • As long as the cells in the area look similar then i mark them for an area  

  • Mapped out the entire brain and differnet sections of the brain  

  • By layering patterns  

  • Mapping of cortical areas  

Localization to connectionism  

  • Follow up work studying the anatomy of the cerebral cortex revelaed dramatic diff in Cytoarchitecture that we now know accounts for many functions  

  • Connectionsm 

  • suggests that mental 

  • phenomena and behavior can be described in 

  • terms of interconnected brain regions 

  • subserving different (sub)functions 

  • Connectism has been and remains the dominant conceptual framwork for understanding brain function  

  • Edward thorndike  

  • William james  

  • John hughlings jackson  

 

 

Neurons are the basic elements for connectivity in the brain their spatial relationships are critically important  

 

Biological sturcture predicts function  

“If you want to understand function, study structure”- Francis Crick 

 

The cell sof the nervous system  

  • Neurons 

  • 86 billion neurons and around the same about of glia 

  • Neurons are similar to other cells of the body but have a distinct shape 

  • Shape of a neuron determines its connections with other neurons and its contirbution to the nervous system  

  • The function of a neuron is related to its shape (although the molecular composition of the cell is also important)   

  • Glia 

  • All neurons have the following major compnents  

  • Dendrites 1 

  • Soma/ Cell body 2 

  • Axon 3 

  • Presynaptic terminals 4 

  • Synapses 5 

  • Always done 1->5  

  • Neurons have many dendrites but only one axon  

  • Descibe as pre and post synaptic neurons  

  • Synapse 

  • Junctional points between neurons (seperated by a small gap) 

  • That tramsits/ receives electircal or chemical impulses  







To keep this concise and easy to review, here are core definitions for the key terms shown in your behavioral neuroscience textbook list:


A–C


  • Acetylcholine (ACh): A major neurotransmitter involved in motor control, memory, and attention.


  • Afferent: Carrying sensory information toward the central nervous system.


  • Amygdala: A limbic system structure key for emotional processing, particularly fear and threat detection.


  • Angiography: Imaging technique used to visualize the location and size of blood vessels in the brain.


  • Anterior: Toward the front or head end of the body or brain.


  • Arachnoid: The web-like middle layer of the meninges surrounding the brain and spinal cord.


  • Arborization: The elaborate branching pattern of a neuron's dendrites.


  • Astrocyte: A star-shaped glial cell providing metabolic support, blood-brain barrier maintenance, and synaptic regulation.


  • Autonomic Nervous System: Branch of the peripheral nervous system regulating involuntary functions (heart rate, digestion).


  • Axon: The long extension of a neuron that conducts electrical impulses away from the cell body.


  • Axon Hillock: The cone-shaped region where the axon emerges from the cell body; site of action potential initiation.


  • Axon Terminal: The end of an axon branch that forms a synapse and releases neurotransmitters.


  • Basal Ganglia: Subcortical structures (caudate, putamen, globus pallidus) essential for motor control and habit learning.


  • Blood-Brain Barrier: Selective vascular barrier protecting the brain from toxins and pathogens in the bloodstream.


  • Brainstem: Brain region comprising the midbrain, pons, and medulla, controlling fundamental life-support functions.


  • Caudal: Toward the tail or posterior end.


  • Central Nervous System (CNS): The brain and spinal cord.


  • Cerebellum: Brain structure responsible for motor coordination, balance, and fine motor learning.


  • Cerebral Cortex: Outer layer of neural tissue covering the cerebral hemispheres, responsible for higher-order cognitive functions.


  • Cerebrospinal Fluid (CSF): Fluid cushioning the brain and spinal cord, circulating through the ventricles and subarachnoid space.


  • Corpus Callosum: The large tract of nerve fibers connecting the left and right cerebral hemispheres.


D–L


  • Dendrite: Branching extension of a neuron that receives synaptic inputs from other cells.


  • Diffusion Tensor Imaging (DTI): MRI technique tracking water diffusion to map white matter fiber tracts in the live brain.


  • Dorsal: Toward the back or top of the head/brain.


  • Dura Mater: The tough, outermost layer of the meninges.


  • Efferent: Carrying motor signals away from the central nervous system toward muscles or glands.


  • Forebrain: Frontal division of the brain containing the cerebral hemispheres, thalamus, and hypothalamus.


  • Frontal Lobe: Anterior cortical region involved in executive function, decision-making, planning, and motor control.


  • Functional MRI (fMRI): Brain imaging method tracking blood-oxygenation changes to detect active brain regions.


  • Glial Cells: Non-neuronal brain cells (astrocytes, oligodendrocytes, microglia) providing structural, metabolic, and myelin support.


  • Gray Matter: Brain regions composed predominantly of neuronal cell bodies, dendrites, and unmyelinated axons.


  • Gyrus: A raised ridge or fold on the surface of the cerebral cortex.


  • Hippocampus: Limbic structure essential for explicit memory formation and spatial navigation.


  • Hypothalamus: Structure regulating homeostatic drives (hunger, thirst, temperature) and controlling the pituitary gland.


  • Interneuron: A neuron that communicates exclusively with other neurons within a local circuit.


  • Ipsilateral: Located on or affecting the same side of the body.


  • Limbic System: Interconnected network (hippocampus, amygdala, cingulate) mediating emotion, memory, and motivation.


M–P


  • Medulla: Lower brainstem structure controlling vital autonomic functions like respiration and heart rate.


  • Meninges: The three protective membranes (dura, arachnoid, pia) encasing the brain and spinal cord.


  • Microglial Cells: Immune cells of the central nervous system that clear cellular debris and respond to injury.


  • Midbrain: Middle portion of the brainstem containing structures like the tectum and tegmentum.


  • Motor Neuron: Neuron transmitting signals from the CNS to effector muscles or glands.


  • Myelin: Fatty sheath surrounding axons that accelerates action potential conduction.


  • Neuron: Primary signaling cell of the nervous system specialized for receiving, processing, and transmitting information.


  • Neuroplasticity: The ability of the nervous system to alter its structure and functional organization in response to experience or injury.


  • Neurotransmitter: Chemical messenger released at a synapse to convey signals between neurons.


  • Node of Ranvier: Gap in the myelin sheath along an axon where action potentials are regenerated.


  • Occipital Lobe: Posterior cortical region dedicated to visual processing.


  • Oligodendrocyte: Glial cell forming myelin sheaths around axons in the central nervous system.


  • Parasympathetic Nervous System: Division of the autonomic nervous system promoting "rest and digest" physiological responses.


  • Parietal Lobe: Cortical region processing somatosensory information and spatial awareness.


  • Peripheral Nervous System (PNS): All nerves and ganglia outside the brain and spinal cord.


  • Pia Mater: Delicate, innermost layer of the meninges directly adhering to the brain surface.


  • Pons: Brainstem region bridging the midbrain and medulla; involved in sleep, arousal, and facial motor control.


S–W


  • Schwann Cell: Glial cell providing myelin sheaths for axons in the peripheral nervous system.


  • Sensory Neuron: Neuron detecting internal or external stimuli and transmitting information to the CNS.


  • Substantia Nigra: Midbrain structure containing dopaminergic neurons crucial for movement control; degenerates in Parkinson's disease.


  • Sulcus: A groove or furrow separating gyri on the surface of the cerebral cortex.


  • Sympathetic Nervous System: Division of the autonomic nervous system mobilizing "fight or flight" responses.


  • Synapse: Functional junction where a presynaptic neuron communicates with a postsynaptic target cell.


  • Synaptic Cleft: The tiny fluid-filled gap separating presynaptic and postsynaptic membranes.


  • Temporal Lobe: Lateral cortical region involved in auditory processing, speech comprehension, and memory.


  • Thalamus: Major sensory relay station directing incoming sensory signals to appropriate cortical areas.


  • Ventral: Toward the belly or underside of the head/brain.


  • White Matter: Nervous tissue composed mainly of myelinated axons facilitating long-distance communication.


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