Kinesiology Notes (Test 3)

Cognitive Neuroscience

Responsible for cognitive processes such as learning, memory, and motivational states

Anterior

Front

Posterior

Back

Superior

Above

Inferior

Below

Rostral

- Toward the face/anterior part of the brain

- Front/top of axis

Caudal

- Toward the back/posterior part of the brain

- Back/bottom of axis

Dorsal

Top or upper side

Ventral

Bottom or lower side

Frontal/Coronal

Separates front and back

Sagittal

Separates left and right

Transverse

Separates top and bottom

CNS

- Differentiated from the PNS

- Consists of the brain and spinal cord, while the PNS includes all other nervous system tissue

Cerebral Hemispheres (Brain Lobes)

- Frontal: Planning and movement

- Temporal: Emotion and language (audition)

- Parietal: Somatosensory processing; attention

- Occipital: Vision

Cerebral Cortex

- Location of processing

- More surface area = more processing

Gyrus (ridges) and Sulus (fissures)

Increase the surface area of the cortex and form brain regions

Brain sulcus

- Grooves on the surface of the brain

- Shallow, surrounds gyrus

Gyrus (picture)

Brain fissure

Deep groove that divides the brain into lobes

Lateral/sylvian fissure (Central sulcus)

- Separates frontal and parietal lobes from the temporal lobe

- Able to separate easily

Longitudinal fissure

- Separates cerebral hemispheres

- Largest fissure

- Able to separate easily

Corpus callosum

Connects hemispheres allowing them to communicate

Hypothalamus

Connects to the pituitary gland and controls the endocrine system

Brainstem

Midbrain, Pons, Medulla

Cranial nerves

Supply muscles of the face, neck, and head and takes the sensory input from them

Gray matter

- Cell bodies, dendrites, and axon terminals of neurons

- Location of processing along with the location of all synapses

White matter

Bundles of axons which connect to different parts of gray matter

Basal ganglia

Cells bodies in the CNS located in the base of the brain

Optic Nerve II

Sight from retina into brain

Oculomotor III

Moves eyelid & eyeball and adjusts the pupil & lens of the eye

Trochlear IV / Abducens VI

Moves eyeballs

Vestibulocochlear VIII

Sensory, hearing and balance (auditory)

Spinal cord

- Part of nervous system that innervates your whole body

- Nerves connect with glands or motor functions

- Cervical: Neck

- Thoracis: Trunk

- Lumber: Back

- Sacral: Bottom of lumber

Dorsal horn

Sensory part of the spinal cord that receives information

Ventral horn

Motor part of the spinal cord that sends information

What is a Stroke?

- Issue with the vascular system carrying blood into the brain

- Blocked artery

Blood brain barrier

- The semipermeable barrier of endothelial cells

- Prevents solutes in the circulating blood from non-selectively crossing into the ECF of the CNS

Ventricular System

- (Ventricles as open chambers) that help with the production & circulation of the CSF

- CSF is produced by specialized tissue containing glial cells and blood vessels called the choroid plexus

- CSF is circulated to the subarachnoid space of the spinal cord

The fourth ventricle:

Directly connects to the cerebral aqueduct and central canal of the spinal cord

Meninges

- Surface protection of the spinal cord

- Dura, arachnoid, and pia mater

- Arachnoid Villi: Allows recycling of CSF

Subarachnoid space

Location of CSF

Cell body

Contains one nucleus

Dendrites

- Short extensions off the cell body

- Site for receiving signals from other neurons

Axon

- Extension away from the cell body

- Some can be myelinated to improve conductivity

- Typically branched at end

Synapse

Site of communication between neurons or between a neuron and a target tissue

Nodes of Ranvier

- Gaps in myelin sheath, only location of action potential

- Signal "jumps" down the axon -> saltatory propagation

Neural impulse

Action potential, electrical signal traveling down the axon

Myelin sheath

- Covers the axon of some neurons and helps speed up neural impulses

- Insulation formed from oligodendrocytes to allow saltatory conduction

Saltatory conduction

The jumping of action potentials from node to node

Axon terminal

Release neurotransmitters into synaptic cleft

Glial cells

Helps regulate the ECF of the CNS through the provision of metabolic and immunological support for the nerve cells

Types of glial cells

Astrocytes, oligodendrocytes, schwann cells, and microglia

Astrocytes

- Star-shaped

- Maintains chemical environment and extracellular ion balance

- Provide nutrients to surrounding tissue

Oligodendrocytes

- Forms myelin sheath in CNS

- Gives structural integrity

Schwann Cells

Forms myelin sheath in PNS

Microglia

- Macrophages: scavenges for plaques, damaged neurons/synapses, and infectious agents

- "Garbage guys" of the CNS

The central nervous system is an:

Electric organ

The brain transmits information from neuron to neuron to form:

Circuits

Circuits

Process information, much like computer circuits process information

Ions

- Atoms with net positive or negative charge

- Ex: K+, Na+, Cl-, Ca++, A- (valence)

Semipermeable membrane

Selectively allows some ions to pass through specific ion channels

Electric Signal

- Current

- To produce movement of an ion, an electrical potential must exist

- To cause movement, an electrical field created by a voltage must exist

Battery

- An electrochemical cell

- Provides a static potential for power or a released electrical charge when needed

Resting Potential

- The neuron is inactive, just waiting for a nerve impulse to come along

- The inside of the cell membrane has a negative electrical charge (some K+ channels are open at rest)

- The resting potential is created by a transport protein called the sodium-potassium pump

- This protein moves large numbers of sodium ions (Na+) outside the cell, creating the positive charge

- At the same time, the protein moves some potassium (K+) ions into the cell's cytoplasm

- This pump also contributes to the negative charge of the inside of the membrane

Synaptic Potentials

- EPSP: Excitatory synapse, Depolarization

- IPSP: Inhibitory synapse, Repolarization

Synaptic Summation

- EPSP & IPSP Cancellation: Excitatory and inhibitory graded potentials cancel each other out

- Spatial Summation: Excitatory potentials from many neurons trigger threshold point

- Temporal Summation: Many excitatory potentials from one neuron triggers threshold point

Action Potential

- All or none response

- Summation of EPSPs and IPSPs causes a large enough voltage at the axon hillock

- Na+ channels open into the neuron and potential becomes more positive

- Na+ channels start to close just before the peak of action potential when K+ channels open, causing repolarization

- When the K+ channels close, the neuron has more K+ channels outside than Na+ channels inside causing the cell potential to drop lower than resting

- Neuron enters a refractory period just before peak action potential when Na+ channels are still closed and K+ are still open

"Battery" setup by storing ions on different sides of the membrane:

Produces signals caused by ions moving through membrane channels

Action potentials travel down:

The axon at rapid speeds (100m/s) but require insulation to do so

Two types of synapses

Electrical and chemical

Chemical transmission

- Occurs at synapse

- Specific post synaptic receptors determine effects of neurotransmitters

Neurotransmitters

Released from the synaptic cleft

Important Neurotransmitters

- Acetylcholine

- Glutamate

- GABA

- Catecholamines

- Serotonin

- Glycine

Acetylcholine (ACh)

Transmitter at the neuromuscular junction that is important for memory; blocked by tubocurarine

Glutamate

Major excitatory neurotransmitter in the brain and spinal cord

GABA (Aminobutyric acid)

Major inhibitory neurotransmitter in the brain

Catecholamines

- Dopamine & Norepinephrine

- Can be excitatory or inhibitory on their targets

- Important in additional regulation, motor control, and DNA is functional in some psychiatric disorders such as schizophrenia

Serotonin (5-HT)

- Made from Tryptophan

- Functional in sleep-wake cycles and depression

- SSRIs: selective serotonin reuptake inhibitors (Prozac)

- Monoamine Oxidase inhibitors prevent the breakdown of catecholamines and serotonin

Glycine

Major inhibitory neurotransmitter in the spinal cord

Stroke

A neurological impairment caused by a disruption in blood supply to a region of the brain

Stroke facts

- Leading cause of adult disability

- Up to 80% of all strokes are preventable through risk factor management

- On average, someone suffers a stroke every 40 seconds in America

Stroke symptoms

Sudden severe headaches, dizziness, confusion, trouble walking & speaking & seeing, numbess/weakness in the face, arms, legs

Stroke strikes FAST

F: Face (smile)

A: Arm

S: Speech

T: Time to call 911

Circle of Willis

- The joining area of several arteries at the bottom (inferior) side of the brain

- Internal carotid arteries branch into smaller arteries that supply oxygenated blood to over 80% of the cerebrum

What artery is a continuation of the internal carotid artery?

Middle cerebral

Which artery supplies the primary sensory and motor cortices in the posterior frontal and anterior parietal lobes?

Middle cerebral

What type of stroke is due to blockage of an artery?

Ischemic

Types of strokes

Hemorrhagic and Ischemic

Hemorrhagic

- 15% of strokes

- Causes by a burst blood vessel

- Leaking of blood causes blood clots to push on the brain

Ischemic

- 85% of strokes

- Blood clots block the blood flow

- Loss of blood & oxygen

- Thrombotic & Embolic

- Small strokes

Thrombotic

Blood clot is stationary

Embolic

Blood clot is traveling

Small stroke

- Transient ischemic attacks (TIA)

- Can lead to Lacunar Lesions

Intracerebral

Arteriovenous malformation (aneurysm)

Subarachnoid

- Aneurysm

- Trauma

Voluntary Movements are controlled through 4 major processes

- Idea: Abstract motivation

- Conform to environmental constraints

- Plan the necessary body movements

- Execution: Activate muscles and correct errors

Brain Regions activated

- Having an idea: Prefrontal cortex

- Conforming to environmental constraints: Posterior parietal cortex

- Making a plan: Supplementary and Premotor Cortex

- Executing the plan: Primary motor cortex

What Cortical area is associated with visual to body centered coordinate transformations?

Posterior parietal cortex

What Cortical area is associated with coordinating bilateral arm movements?

Supplementary Motor Area (SMA)

Premotor Areas

- Planning of specific body segment motions and learning through observation of movements

- Once plans are transformed into body coordinates, planning of body segment motion occurs