Chapter 3 Flashcards
Neuroscience
Neuroscience
The study of the brain and the nervous system
Key Methods in Studying the Nervous System
- Examining autopsy tissue
- Testing the behaviour of patients with an assumed damage to certain parts of the brain
- Recording electrical brain activity through multiple electrodes attached to the surface of the skull
- Animal studies
Types of Neuroimaging
- MRI (Magnetic Resonance Imaging)
- fMRI (functional Magnetic Resonance Imaging)
- CAT/CT (Computerized Axial Tomography
- PET (Positron Emission Tomography)
- TMS (Transcranial Magnetic Stimulation)
- DTI (Diffusion Tensor Imaging)
CT/CAT Scan
- Computerized Axial Tomography
- Structured Imaging
- Produce clear, detailed, 2D images of the brain or other organs (using which are then compiled to make one 3D image made up of various 2D images taken from different angles
- They provide better images than traditional X-rays and can be ‘sliced’ in a way and examined
MRI
- Magnetic Resonance Imaging
- Structured Imaging
- Uses as strong magnetic field in order to produce 3D images of the brain
-Uses less radiation than a CT and produces cleaner images
Why are CTs sometimes used instead of MRIs?
-CTs are better at detecting problems such as strokes, blood vessel abnormalities, cancer/tumours,etc.
-MRIs are more useful for soft tissue injury
-In the case of an emergency, CTs are faster
-A CT will also be used for patients who cannot enter a strong magnetic field
DTI
- Diffusion Tensor Imaging
- Structure Imaging
- One of the newest neuroimaging methods, DTI maps the orientation and integrity of white matter to assess damage within the brain, then producing a DTI map
- This has an advantage over MRIs and CTs in that neither of them show white matter
What is the difference between structural and functional imaging?
Functional imaging is used in order to observe brain function and to learn about activity in specific brain areas during specific behaviours; structural imaging is used to map out and quantify the structure and of the brain
EEG
Recording brain activity through multiple electrodes attached to the surface of the skull using electroencephalogram to measure electrical brain activity under the scalp. This method can only provide general ideas and cannot explore anything deeper within the brain
TMS
- Transcranial Magnetic Stimulation
- Functional imaging
- Targets specific parts of the brain with an electromagnetic pulse to specific areas, temporarily disabling it. The change in activity is then noted and scientists can use that to infer what this part of the brain is responsible for
PET
- Positron Emission Tomology
- Functional imaging
- A non-harmful, radioactive chemical is injected into the blood stream and then taken up into the brain. The patient then does various activities and the highest concentration of radioactivity in the brain can be measured to infer which part of the brain is most active during said activities
- This can also be used to observe the use of different neurochemicals
- Provides a deeper look into brain activity than the EEG can
- Can show activity over hours/days
fMRI
- Functional Magnetic Resonance Imaging
- Functional Imaging
- Measures oxygen levels in the brain to see which parts of the brain are most active during certain activities. This is coupled with an increased blood flow
- This is preferred over the PET because no radiation is required
- This only shows activity over minutes/hours, so it is not as long-term
Two major components of the nervous system
- Central Nervous System
- Peripheral Nervous System
PNS
All the nerves in our bodies, delivering info between the periphery and CNS; everything outside the brain and the spinal chord
CNS (3)
- Brain and spinal chord
- Spinal chord starts at the base of the brain and down the back inside the bony spina column
- Acts as a highway for sensory information
Neurons
Cells which carry information between parts of our bodies and nervous systems
Afferent Neurons
Neurons carrying information from the PNS to the CNS. This is often sensory neurons taking a feeling to be processed.
Efferent Neurons
Neurons carrying information from the CNS to the PNS. This is often motor skills as the brain tells the the hand to move
Interneurons
These act as sort of relays between different classes of neurons (for example located between sensory and motor neurons)
Two Main Parts of Peripheral Nervous System (2)
Somatic Nervous System and Autonomic Nervous System
Somatic Nervous System (1)
All the nerves that gather sensory information from the body, neck and head and deliver it to the spinal chord/brain
Autonomic Nervous System (1)
Operates without control/thought from the CNS, regulating involuntary physiologic processes such as heart rate, blood pressure, respiration, etc.
Two parts of the Autonomic Nervous System (3)
- Sympathic Nervous System
- Parasympathetic Nervous System
Both are a collection of nerve cells throughout the body
Sympathetic Nervous System (6)
This is the part of you which is active during stress,
-activating things like:
an increase heart rate
directing blood to areas which need more oxygen
stopping non-essential bodily functions
pupils dialating
glucose release
Parasympathetic Nervous System
The parasympathic nervious system then works to ‘undo’ what the sympathetic nervous system has done
- slowing heart rate
- coming down
Spinal Chord Injury (4)
- This occurs when the nerves which make the spinal chord are damaged in some way
- The higher up the spine, the more that is damaged in the body
- Quadriplegic: Paralyzed everywhere other than the head and neck
- Paraplegic: Paralyzed in the lower limbs but not the upper
The Hindbrain (5 points, 4 parts)
- Part of the brain closest to the spinal chord
- Medulla
Regulates basic functions, breathing, heartbeat, sneezing, linking cardiovascular and respiratory systems - The Pons
acts as a bridge between the medulla and the other brain areas and is responsible for sleep, dreaming, breathing, swallowing, eye movements, facial sensation and expression (unconscious processes)
In the pons is the locus coeruleus, in which there is a collection of neurons with long axons that project through the brain and spinal chord, influencing the CNS. Also has neuropinephrine, a neurotransmitter used for arousal and attention
-Cerebellum
This is important in motor coordination, storing information to be recalled automatically once it is learned. This includes muscle and balance and general complex motor movement things
-The reticular formation
This is a network of nuclei extending from the hind brain to the midbrain, plays a role in the sleep wake cycle and wakefulness and a level of arousal
The Midbrain (4)
- Located above the pons
- Only really concerned with the substantia nigra
- Production of dopamine neurons
- Communicate with the forebrain to regulate fluidity of motion
Forebrain 1 (1) 2 (5) 3 (4) (4) 4 (3) 5 (8) 6 (6)
- Two cerebral hemispheres, connected by a band of white matter called the corpus callosum
-The Thalamus
Thalamic nuclei serve as relay stations for incoming sensory information
-The hypothalamus
Important for motivation, things like eating, drinking, sex, sleep, maternity general urges
Also controls the endocrine or hormone system
-The Pituitary Gland
Controls chemical messengers involved with growth, reproduction, metabolism, stress reactions
Also produces releasing factors which impact endocrine glands in ovaries, testes, thyroid and adrenal glands
-The Limbic System
Series of interconnected brain structures controlling motivation, emotion and learning/memory
-Basal Ganglia
Made up of the following nuclei working as a functional unit: Caudate nucleus, putamen, global pallides, substantial nigra, nucleus accumbens (reward learning)
Responsible for cognitive flexibility and regulating/coordinating voluntary movement control
-Cerebral Cortex
language, thought, consciousness, localization of function
primary sensory/motor areas: processing voluntary movement
association cortex: thinking, planning, higher order info processing
The Limbic System 1 (3) 2 (4)
- Amygdala
-Located in the temporal lobe
-Recognizing, learning about and responding to stimuli connected to fear - Hippocampus
- Learning/memory
- Influence episodic memories or memories having to do with individual events
- Has to do with navigating space
-Also is a region of neuroplasticity, meaning in adulthood new neurons are produced here
Limbic system also includes the hypothamalus and the thamalus
4 Divisions of the Cerebral cortex
- Occipital lobe
- processing visual stimuli
- info about colour, complex patterns and motion - Temporal lobe
- auditory stimuli and language information processing
-other areas in temporal lobe give meaning to sound
-Wernicke’s area (understanding) Brocas area (speaking) - Parietal Lobe
- Processes tactile information (touch, pressure vibration, pain)
- depth perception, where objects are in relation to one another - Frontal lobe
- understanding social relationships
- movement
- temporal planning
- motor skills, voluntary
Pre fontal lobe: Short term, working memory, planning study schedules and bus routes, ‘holding’ info
Dendrites
The parts of a neuron which receives info from other neurons
Axons
move signals out of the cell
Axon terminal
Part of the axon where neurotransmitters are released
Glia
Non-neuronal cells which act as a barrier for virus’ and bacteria between the CNS and circulatory system. These fells do a lot of things
Categories:
Astroglia (creates blood barrier)
Oligodendroglia (Insulates axons from neuronal activity from surroundings)
Ependymal cells/Microglia
Explain the process of how a neuron sends a signal
- Resting potential-action potential through ion channels bringing in charged ions (sodium-potassium pumps)
- Action potential is created in neuron which travels through until triggering voltage sensitive ion channels on the axon terminal
- This brings in Calcium ions which bind the synaptic vesicles to the axon terminal
- neurotransmitters stored inside are then released and move across the synapses
- chemical reaches receptors on the dendrites of another neuron which then processes the chemical signal
- Electric signal is then sent through again
Acetylcholine (2)
stimulating muscles
communicating between motor/sensory neurons
Dopamine (3)
mood
control of voluntary movement
reward mechanisms
Norepinephrine (5)
sympathetic nervous system
arousal
vigilance
mood
constricts blood vessels
Serotonin (4)
mood
appetite
sleep
learning/memory
GABA (2)
reduces activity in neurons it binds to
associated with sleep
Glutamate
everything?
learning and memory
Neuroplasticity
Brains ability to make new neural connections or to reorganize in response to injury or experience
Traumatic Brain Injury
Injury to the brain from a blow to the head
Acquired Brain Injury
Injury to the brain resulting from infections, exposure to toxins, strokes.
