NEUR1020 module 2

Cerebrum

Area of the brain responsible for all voluntary activities of the body

Cerebral Cortex

Outermost surface of the brain (where grey matter is locates)

Grey Matter

Contains neuron cell bodies. Also highly folded to maximise surface area

White Matter

Where all the wiring i.e axons of the neurons connecting to the spinal cord and to other areas of the coretx

Frontal Lobe

Responsible for executive functions (reasoning, planning, problem-solving, inhibitary control, working memory)

Motor Functions

Complex muscle-and-nerve acts that produce movement

Parietal Lobe

Receives sensory input for touch and body position

Occipital Lobe

Primary visual cortex. Processes shapes, colours, orientation, motion

Temporal Lobe

A region of the cerebral cortex responsible for hearing and language

Medial Temporal Lobe

Controls the limbic system (learning and memory). Also is the location for amygdala and hippocampus

Amygdala

Alerts us to threats/dangers

Hippocampus

A neural center located in the limbic system that helps process explicit memories for storage.

Corpus Callosum

Neuron connections between left/right hemispheres

Phineas Gage's accident

After suffering frontal lobe damage he lost all of his inhibitory functions

Broca's Area

Area that controls language expression. Located in the left frontal lobe

Wernicke's Area

Controls language reception. Located in the posterior temporal lobe

significance of Brainstem

Important for the nervous system

Automatic Nervous System (Sympathetic Nervous System)

Controls involuntary actions (heart-rate, respiration, fight/flight)

Automatic Nervous System (Parasympathetic Nervous System)

Lowers heart-rate, resperation

Somatic Nervous System

Voluntary action. Controls the motor and sensory functions

Brainstem Division

Controls heart-rate, respiration, regulation of blood pressure, body temperature

Reflex Centres

Responsible for coughing, sneezing, swallowing, vomiting

Persistent Vegetative State

Severe damage to the upper brain causing a coma like status. If the brainstem isn't damaged, normal functions can be retained

ALS (Amyotrophic Lateral Sclerosis)

Motor neuron disease. Retain normal cognitive functions but the patient can't move

Cerebellum

Responsible for sense of balance, coordination of complex movements, motor learning

Dendrites

Branchlike parts of a neuron that are specialized to receive information

Axon

The neuron extension that passes messages through its branches to other neurons or to muscles or glands

Axon Terminal

Endpoint of a neuron where neurotransmitters are stored. Also secretes neurotransmitters to send signals across synapses to other neurons

Synapse

Junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Oligodendrocytes

Type of glial cell that wrap axons in a myelin sheath.

Microglia

Phagocytic cells that ingest and break down waste products and pathogens

Astrocytes

Provide structural and metabolic support for neurons.

Multiple Sclerosis

A chronic disease of the central nervous system marked by damage to the myelin sheath

Membrane Potential

Voltage difference across a membrane

Resting Potential

At rest, there is more positive ions on the outside than inside the cell, which gives more negative charge

Action Potential

Change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

Depolarisation

Change in potential difference from negative to more positive across the membrane

Repolarisation

Return of a cell membrane to its resting potential.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons

Process of Action Potential

Na+ Channel opens when voltage exceed threshold. Na+ flows into cell leading to more negative charge. K+ flows out of the cell membrane causing the voltage to return back to normal (-70v)

Synaptic Vesicle

Stores neurotransmitters in pre-synaptic terminal

Neurotransmitters are taken back into the...

pre-synaptic terminal to be recycled

Re-uptake Pump

Recycles neurotransmitters and regulates the level of neurotransmitter present in the synapse

Enzymes in synapses

Break down neurotransmitters in synaptic cleft

SSRI (Selective Reuptake Inhibitors)

Antidepressants

MAOI (Monoamine Oxidase Inhibitors)

Breaks down inhibitors and results in more neurotransmitter

Brain Lesion Assumption

Whatever changes in behaviour/cognition must rely on that first part of the brain that is damaged

Problem with Single Neuron Recording

Highly invasive (as the electrodes are directly in the brain)

Auditory Event Related Potentials

Measures of cortical brain activity related to auditory stimuli

ERP can...

Show precise time of info processing in the brain

ERP can directly measure the...

electrical activity in the brain

PER (Positron Emission Tomography)

Uses radioactive substances injected in the bloodstream to map out neurotransmitters or receptors in the brain

fRMI

Measures brain activity by detecting changes associated with oxygen levels

Issue with fMRI

No precise timing of neural activity. Also expensive

Neuroplasticity

Capability of the brain to alter its functional organisation as a result of experience

Neurogenesis and Synaptogenesis

Generation of new neurons and synapses

"Grandmother Cells"

Neurons would encode to a specific concept such as your grandmother

Jennifer Aniston Cells can be found in...

Hippocampus of Epilepsy Patients

Spreading Activation Model Theory

Neuron represent a specific concept. Share connections with neurons that represent related concepts. Activation of one neuron leads to spreading activation to related or connected neuron

Learning and Memory

Making/Strengthening connections between neurons that represent associated concepts

Ramon Y Cajal's Research results

Neurons do not regenerate

Neurogenesis

Neurons never regenerate or repair but new neurons are constantly born throughout life from neural stem cells

Synaptogensis

Generation of new brain connections

Enriched Conditions lead to...

Growth of dendrites and more extensive synaptic connections

Long Term Potential

Change in structure of synapses to give stronger signal from pre-synaptic to post-synaptic

Strength of synapse connection (on dendrites)...

Affects the graded potential at the axon hillock

Strong Stimulus (Synapse Connection)

Causes large change in membrane potential

Weak Stimulus (Synapse Connection)

Causes small change in membrane potential

Hebb's Law

Neurons that fire together, wire together

Hebbian Learning

Repeated firing of pre-synaptic and post-synaptic neuron at the same time strengthens synaptic connection

Cerebrum

two hemispheres, divided by the longitudinal fissure

longitudinal fissure (corpus callosum)

separates left and right hemispheres of the brain

corpus callosum

nerve fibers connecting the two hemisphere

cerebral cortex

outermost surface layer of the cerebrum

Phinease Gage Case

Iron Rod accident
reported personality change -> discovery of frontal lobe and executive control of behaviour

Broca's Area

Left Frontal Lobe

Broca's Aphasia

inability to produce speech

Wernicke's Area

Left Posterior Temporal Lobe

Wernicke's Aphasia

inability to comprehend speech

Wilder Penfield

stimulated brain with electrical probes while patients underwent surgery for epilepsy
created maps of sensory and motor cortices

Homonculus

brain function "mapped" by electrical stimulation

Central Nervous System

brain and spinal cord

peripheral nervous system

the sensory and motor neurons that connect the CNS to the rest of the body

Somatic Nervous System

voluntary motor and sensory

autonomic nervous system

involuntary movements
(sympathetic and parasympathetic nervous systems)

sympathetic nervous system

Emotional Arousal
fight or flight

parasympathetic nervous system

nerves that return the body to resting rate
rest and digest

Brainstem

carries information between the cerebral hemispheres, cerebellum and spinal

Medulla Oblongata

controls many vital functions such as respiration and heart rate.

Homeostasis

A tendency to maintain a balanced or constant internal state; blood pressure, body temperature

Persistant Vegetative State (PVS)

Condition in which a person is alive but unaware, unable to communicate or to function independently at even the most basic level

Locked-in syndrome

Individual is aware and capable of thinking but is paralyzed and cannot communicate

high level brain functions

Cerebtal Hemispheres
Planning, reasoning, problem=-solving (Frontal Lobe)
Language and Perception

low level brain function

Brainstem
autonomic nervous system function
heart-rate, respiration, blood pressure

Cerebellum

A large structure of the hindbrain that controls fine motor skills.

Primary Motor Cortex

Movement = sends signals

Primary Sensory Cortex

Sensation = receives signals

Brain Lesions

explains normal brain function by examining what changes when part of the brain is damaged
stroke or brain injury in humans
induced lesions in animals

Single Neuron Recording

A type of electrical recording; recording the action potential from individual neurons; changes from individuals neurons

EEG (electroencephalogram)

measures voltage changes from electrodes on the scalp
brain activity and constant oscillations (brain waves)