Please enable JavaScript.
Coggle requires JavaScript to display documents.
LU3 COGNITIVE NEUROSCIENCE - Coggle Diagram
LU3 COGNITIVE NEUROSCIENCE
Brain Mapping Research
(Insight into Human Cognition)
Language
Aphasia (ASL), localization of brain, brain plasticity, processing of content and function words
Brocha's and Wernicke's area involved in human language function
Loss of speech production - due to the damage to left frontal lobe (Brocha's area)
Brocha's Aphasia (speech affected)
understand but cannot answer appropriately spoken or written speech
speech is not fluent
Loss of damage comprehension - due to damage on the upper back of the left temporal lobe (Wernicke's area)
Wernicke's Aphasia (comprehension/understanding affected)
cannot understand spoken orr written speech
unable to understand any commands/questions
speech is fluent but disorganised
Different parts of brain involved in processing content (nouns) and function words
Applications
Types
fMRI - Broca and Wernicke's area involved
PET scans - rehab training to improve their language ability
Usefulness of imaging - How the brain process different types of words
Memory
Functions of working memory, role of hippocampus, implicit and explicit memory and long term memory
Working memory (retrieval and coding) - working memory not generalized, different sorts of processes carried out in different regions
Greater activation at higher levels of load (higher memory load lasts longer - continuing activation)
Investigate role in explicit and implicit memory of events
Retrieval and metacognition - greater activity in episodic learning (encoding) while the right hemisphere showed more activity in episodic retrieval
Applications
PET scan focusing on the hippocampus (region in temporal lobe) to proof the existence of
Implicit memory (unconscious)
Explicit memory (conscious)
Results
Hippocampus was not activated in implicit memory test
but in left prefrontal cortex and secondary visual cortex
Hippocampus was activated in the explicit memory test
Concept Categories
Categorization task, name finding
Different areas activated depending on nature of categorization task - increase cerebral blood flow
Broca's area alone not responsible for name finding - other regions of the cortex are involved in semantic association
Name finding depends on specific name finder function in restricted area, but rather part of complex system of concept/ categorization that has neural components in various regions of the cortex
Disorders
Bipolar and Unipolar Disorder
Schizophrenia
Mental disorder characteristically marked by
Illusions
Delusions
MRI ( smaller brain volume - ventricular and sulcal enlargement)
PET scan - decrease glucose utilization in the frontal lobes - relative hypofrontality
ERP used to determine function - cause of language abnormalities in schizophrenia
Language of schizophrenia
incoherence and tendency to produce loose and irrelevant associations
language dysfunction did not distinguish between sentences that made sense and those that did not
Autism
Neurologiacl/brain disorder that afects the functioning of the brain
autism impacts the normal development of the brain in the areas of socail interaction and communication skills
Volume of the brain is larger in male subjects with autism
Dyslexia
Difficulties with recognizing words and spelling
having problem in phonological processing
Application
Association cortex = required in reading. To convert what is perceived as print into the phonologic structures of the language
The nervous system in vertebrates
Peripheral nervous system
Central nervous system (brain & spinal cord)
Neurons = to receive and transmit information using electric impulses
Axon = Send messages from the cell body
Dendrite = receives messages to the cell body
Soma = neuron body (contains DNA)
Synapse = small gap between 2 neurons
Neurotransmitters = Chemical signals released across synapse to allow neutrons to communicate
Brain Research: The Development
Late 18th & Early 19th Century
Franz Joseph Gall
Phrenology
Relate structure of brain & people behavior
Emergence of theory of localization
Paul Broca = Broca's Area
Carl Wernicke = Wernicke's Area
Late 19th & Early 20th Century
Hughlings-Jackson
Observe recurrent pattern of epileptic seizures in patients
Found connection between specific brain areas and specific body side
Localization of function in the 2 hemispheres (Theory of contralateral control)
Evidence by Eduard Hitzig & Gustav Fritsch
Muscle movement stimulated by direct electricity application to brain
Did experiments on dogs
David Ferrier
Continued experiments on monkeys, frogs, guinea pigs
Used ablation (surgical removal)
"Brain is the organ of the mind"
Insights from Psychology
Sheperd Ivory Franz
Challenged theory of localization of function
Training animals new habits after removal of frontal lobe
Animals could relearn lost new habits
Karl Lashley
Says that theory of localization is oversimplified
Experiment on white rats
Intelligence = global function (can relearn)
Principle of Equipotentiality
Parts of the brain have the equal potential to fulfill the function of a damaged part
Principle of Mass Action
When a functional area of cortex is damaged, its ability to perform previously mastered complex functions may be lost in proportion to the extent of the injury
Insights from Neurosurgeons
Roberts Bartholow & Harvey Cushings
Investigate "the pulsation of the brain"
Conducted on conscious patients
Insert electrode with weak electric current in the human brain
Findings = Stimulating localized brain areas could produce specific muscular contractions
Wilder Penfield
Continued brain exploration while treating his patients (epileptic seizures, brain tumours
Construct MAP of brain areas
Donald O. Hebb
Attempted to explain how neural circuits work
Cell Assembly
1960s & Beyond
The visual system (David Hubel & Torsten Wiesel)
Visual field = area that is visible to you while your eyes are not moving
Receptive field = area of the visual field that will produce a response in a given cell
Found feature detectors
Found the connection between the eye and cortical neurons are permanently disrupted when kitten is deprived of the use of one eye for a period, by closing its eyelid
Split-Brain Research (Roger Sperry)
A research that includes severing of the corpus callosum
Specialization of the hemispheres (left and right side)
Investigated the role of the 2 hemispheres
Research done on monkeys
Remove the corpus callosum
After surgery, monkeys behaved normally
Procedure was then done on human patients with epileptic seizures
No connection between the 2 sides
Left side = language, mathematical thinking
Right side = pattern-matching tasks, recognising faces, spatial orientation
Fascinating insight of human brain
Plasticity : Cameroon Moot case
When Cameron Mott was 6 years old, she underwent surgery to have one side of her brain removed to prevent seizures. She could be playing and become suddenly rigid and collapse on the floor.
Doctor suggested : Radical suggestion, radical solution.
called hemispherectomy
removal of half of the brain
Since the left side of the body is controlled by the right side of the brain,doctors knew that Cameron would be paralyzed on her left side when she awoke
But they also knew that the brains of children have amazing abilities to rewire themselves.
Cameron was immobilized for the first two days after the surgery to allow her brain to stabilize.
Then she went into an intensive physical therapy program
Four weeks after the surgery, she walked out of the hospital
Phantom Limbs
sensation that an amputated or missing limb (even an organ, likethe appendix) is still attached to the body and is moving appropriately with other body parts.
Aproximately 5-10 % of individuals with an amputation experience phantom sensation sensation in their amputated limbs , and the majority of the sensations are painful
Sobel
In other words, the brain comes equipped with a kind of blueprint of where the body parts are going to be so that even if they fail to develop their “ghosts” continue to exist in the brain.
According to the Discover article, a body is deprived of a portion of itself, yet that portion continues to be represented in the brain and hence is “felt.”
The Neuroscience Approach (Cognitive Neuroscience)
Attempt to explain cognitive processes in terms of underlying brain mechanisms
Describe the biological ‘hardware’ upon which mental ‘software’ supposedly runs
Neuroscientists
Learn more the structures and functions of the human brain and how they relate to the behaviors we observe in people
using language
solving problems
remembering
The Biology of the Mind
Brain
Most complex organ of the body
Consists of approximately 10 billion nerve cells (neurons) and billions of interconnecting fibers
Approximate length = 15 cm Approximate weight = 1400 g ( 3 pounds/ 1.4 kg)
parts
cereberum
Divided into right and left hemispheres, which are joined by the corpus callosum.
Its outer folded layer is called the cerebral cortex. The surface of the cerebrum is the cerebral cortex.
The cerebrum is the largest part of the brain and controls all conscious thoughts, experiences, and actions.
major parts & their function
temporal lobe
language
hearing
memory
vision
occipital lobe
First place in cortex where visual information is processed
parietal lobe
Receive signals from the touch system
important for vision and attention
perception of stimuli
frontal lobe
Higher functions language, thought, memory, motor functions, problem solving, movement
The frontal lobes are extremely vulnerable to injury due to their location at the front of the cranium.
Studies have shown that the frontal area is the most common region of injury following mild to moderate traumatic brain injury.
Studies have shown that the frontal area is the most common region of injury following mild to moderate traumatic brain injury.
cerebellum
The cerebellum is the second largest part of the brain
It controls posture and balance.
Recent research also suggests a role in higher cognitive processes.
brain stem
It controls processes basic for survival, such as heart rate, breathing, digestion, and sleep.
It is the main route of communication between the rest of the brain, the spinal cord, and the nerves that run throughout the body.
It also has its own set of nerves that send and receive signals to the face, mouth, tongue, eye muscles, ears, and balance sensing vestibular organs
Cerebral Cortex
Surface of brain = cortex (i.e. gray matter)
Decision making organ of the body
Initiates all voluntary actions
Stores all our memories where our knowledge of language resides
Receives messages from all sensory organs
3 mm thick very thin layer .The area is a convoluted pattern packed into a small space inside the skull.
Cerebral Hemisphere
Composed of cerebral hemispheres (left & right), joined by corpus callosum
The left and right hemisphere are separate but connected.
Contralateral brain function
Right hemisphere controls left side of body
Left hemisphere controls right side of body
Corpus Callosum = large band of fibers that connects the left and right hemispheres of the cerebral cortex.
Brain Mapping Techniques
Structural
X-ray Techniques
Cerebral Angiography
Useful in detecting disorders associated with
abnormalities in brain arteries
A procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the brain.
Computed Tomography
Tomography
Representation of a section
Graphein = to write
(Greek) Tomos = cut, section
Tomograph
An image slice through an organ, without the interference of all layers of tissue present in X-ray images
X-ray films appear blurry because
they are 2-D rendition of our 3D body
focus on one plane (slice)
Computer Axial Tomography (CAT)
Less radiation than traditional x-ray
Computer technology enable ‘deblurring’ of picture & reconstruction of a complete brain image from multiple views
Advantages
Safer
The fan shaped beam exposes the body
to less radiation than traditional x-rays
More precise
only takes a cross section of an organ, avoiding problem of
interference of all the layers of tissue present in x-ray images
Clearer image of brain structures
‘deblurring’ by computer technology – 3D
Disadvantage
Doesn’t indicate when an activity is occurring in the brain
Magnetic Resonance Imaging (MRI)
Uses a magnetic field to take images of the inside of your body
Assumes atoms in the body will react to magnetic field
Based on radio signals emitted by the protons in the human body
Advantages
No X-rays or radioactive material is used
Resolution of the image is sharper / clearer than CAT scans
Flexibility
allows the researcher to distinguish
different structures of the brain
gray/white matter and cerebrospinal fluid
Disadvantages
Slow
for an image to be generated
Cannot be used in patients with metallic devices, like pacemakers
May cause claustrophobic reaction in some patients
Functional
Electrophysiological Techniques
Electroencephalography
Advantages
Able to trace rapid changes in neural activity
Can record activations in brains of people who are fully conscious & engaged in various activities in natural environment
Disadvantages
Typically, noninvasiveness –relative
Possible interference from movement, heartbeats
Sometime, invasive electrodes used, as in intracranial EEG
Provide fine-tuned reading of rapidly occurring changes
Tracings/Recordings of patterns of electrical activity in the brain
Non-invasive and painless procedure
Take brief patient history
Apply electrode leads to the patient's scalp
Run the test
A test of the function of the brain itself
records the electrical activity on the brain's surface
image the brain while it is performing cognitive task
detect the location and magnitude of brain activity involved in the various types of cognitive functions
Event-Related Potentials (EPRs)
Subject presented with a stimulus during EEG process
Record voltage change around the stimulus
Repetitions of event – average the values
Evoked response provides a picture of neural activity changing over time as the brain processes information
Blood-Flow Techniques
Positron Emission Tomography (PET)
Method of measuring cerebral blood flow
while subject carries out cognitive tasks
Uses radioactive isotopes
PET scans look at bodily process by detecting the decay products from radioactive tracers injected into the body
Advantages
Provides an image of brain activity as a cognitive task is occurring
locate activity in specific parts of the brain
Disadvantages
Requires the use of cyclotron, an expensive
equipment to provide the radioactive isotopes
Not as sensitive to changes over milliseconds
Radioactive material used
Single Photon Emission Computed Tomography (SPECT)
Functional Magnetic Resonance Imaging (fMRI)
Detect changes in magnetic state of blood using MRI scanners with fast imaging techniques
Record changes in oxygen level & blood flow in various brain locations as subjects perform various cognitive tasks
technique for determining which parts of the brain are activated by different types of physical sensation or activity
Advantages
Provides information about
brain structure and function
Safer
Less harm to patients as no X-rays or radioactive material is used
Allows researchers to infer which locations are involved in specific activities
Brain Mapping
Attempt to provide a complete picture about how the brain works
Relate the brain's structure to its function
Find what parts of the brain give us certain abilities
Goal
to achieve a 3-dimensional (3D) map of the brain, representing the surface, the structures within, and the functions performed by components of structures
Structures
where the components of the brain are located
Functions
how the components act
interact to receive and integrate information
and to produce behavior
Additional resource
Neuroscience is a field of science that collaborates closely with mathematics, linguistics, engineering, computer science, chemistry, philosophy, psychology, and medicine.
Researchers may investigate brain activity in people suffering from diseases such as Alzheimer's. MRI scans and computerised 3-D models are among the tools used.
Von Hemholtz, a German physician and physicist, measured the rate at which nerve cells produced electrical impulses in the nineteenth century.
Gamillo Golgi, an Italian physician, pathologist, and scientist, used silver chromate salt to examine neurons in 1873.
Santiago Ramón y Cajal, a Spanish pathologist, histologist, and neuroscientist, proposed in the early twentieth century that neurons are self-contained nerve cell units.
Neuroscientists can now study the structure, functions, development, abnormalities, and ways the nervous system can be altered thanks to scientific advancements.