Chapter 2: Structure & Function Flashcards
Phylogenetic Division
Groups parts of the brain based on developmental history and evolutionary history
Forebrain, midbrain, hindbrain
Brain Stem
Medulla and pons (in hindbrain), + midbrain and some structures of the forebrain
Medulla Oblongata
Transmits info from spinal cord to brain & regulates life support functions (respiration, blood pressure, coughing, sneezing, heart rate, vomiting)
Pons
Neural relay center, facilitates crossover of info between left side of body and right side of brain (and vice versa)
Also involved in balance and processing visual and auditory info
Cerebellum
Neurons coordinate muscular activity, balance, general motor behaviour/coordination
One of most primitive brain structures
Lesions can cause irregular/jerky movements, tremors, balance impairments
Implicated in ability to shift attention between visual and auditory stimuli, and dealing with temporal stimuli (e.g. rhythm)
Midbrain
Located in middle of brain
Tectum & tegmentum
Reticular formation
Tectum & Tegmentum
Involved in relaying info between brain regions (e.g. cerebellum and forebrain)
Reticular Formation
Keeps us awake and alert, involved in sudden arousal to respond to threat
Forebrain: Subcortical Structures
Thalamus
Hypothalamus
Hippocampus
Amygdala
Cerebellum
Medulla
Spinal cord
Entorhinal cortex
Olfactory bulb
Thalamus
Switching station for sensory information; also involved in memory
Hypothalamus
Regulates basic biological functions, including hunger, thirst, temperature, and sexual arousal; also involved in emotions
Hippocampus
Involved in learning, memory and emotions (indexing system for memories, search engine)
Amygdala
Involved in memory, basic emotion, and aggression (+ emotional reactivity of memories)
Spinal Cord
Transmits signals between brain and rest of the body
Entorhinal Cortex
Memory
Olfactory Bulb
Smell
Cerebral Cortex Lobes
Frontal
Parietal
Temporal
Occipital
Cerebral Cortex
Half dozen layers of neurons with white matter beneath, which carries info between cortex and thalamus or between cortex parts
Corpus Callosum
Anterior Commisure
Central Sulcus
Lateral Sulcus
Corpus Callosum
Connects right and left hemispheres frontal, parietal, and occipital lobes
Anterior Commisure
Connects left and right hemispheres of temporal lobe
Central Sulcus
Prominent shadow groove on surface of brain divides frontal and parietal lobes
Lateral Sulcus
Defines the temporal lobe
Frontal Lobe
Underneath forehead
thinking, speaking, memory, movement
Motor cortex
Prefrontal cortex
Higher order cognition closest to the front of the brain
Motor Cortex
Precentral gyrus
Directs fine motor movements, premotor cortex involved in planning movement
Prefrontal Cortex
Executive functioning (planning, decisions, strategies, inhibiting behaviours, working memory)
Damage can cause change in personality, mood, affect, inhibition
Longest period of maturation, first to go with aging
Parietal Lobe
Underneath the top rear part of skull): processing sensory info, language, touch
Contains somatosensory cortex (in postcentral gyrus)
Gyrus
Convolution or ridge of the brain
Occipital Lobe
Back of head
Vision and colour perception
Depth perception somewhere in the middle (not V1, but not right beside temporal)
As get closer to temporal, functions to identify what things are (build percept)
Temporal Lobe
Side of head
Process auditory info and recognize faces (hearing, learning, feelings)
Damage can result in memory issues (because close to hippocampus and amygdala)
Localization of Function
Mapping the brain
Faculty Psychology
Gall
Theory that different mental abilities were independent and autonomous functions carried out in different parts of brain
Phrenology
Spurzheim
Theory that psychological strengths and weaknesses correlated to relative sizes of brain areas (bumps on the skull)
Contradictions of Phrenology
Size of brain doesn’t correlate to its power
Different faculties are not wholly independent (independence of functions)
Paul Broca
Damage to Broca’s area (left frontal lobe) resulted in aphasia
Aphasia: disruption of expressive language
Broca’s Aphasia: person unable to produce many words or to speak fluently
Does not affect comprehension
Carl Wernicke
Wernicke’s area: superior posterior region of temporal lobe (left)
Wernicke’s aphasia (fluent aphasia): produce speech with fluent contours of pitch and rhythm, but speech makes no sense (issue with speech production)
+ impairments with ability to understand speech
Primary Somatosensory Cortex
More sensitive body parts (e.g. hands) take up more space (doesn’t correlate to size, but to sensitivity)
Wilder Penfield
Stimulated areas of somatosensory cortex with patients awake to map function
Mapped both sensory and motor cortexes
Karl Lashley
Brain ablation: removal of parts of the brain
Study brain ablation in rats learning to run mazes
Impairment related to total amount of cortex removed, not the area removed
Cognitive functions therefore must be dynamic and interconnected
Plasticity: some brain regions can take over the function of damaged regions (more chance when young)
Lateralization
Two cerebral hemispheres play different roles when it comes to certain cognitive functions like language
Language Lateralization
Most show specialization for language in left hemisphere
In these people left hemisphere is more likely to be larger, especially in language areas (left hemisphere dominance)
Bilateralized individuals show no difference in hemispheres
Left Hemisphere
Left hemisphere is better at processing serially (events in sequence)
E.g. words in a sentence
Right Hemisphere
Right hemisphere more synthetic (put elements together to make a whole)
E.g. constructing maps or spatial structures, drawing sketches
Right hemisphere has larger parietal and temporal lobes
Better integration of visual and auditory info and better spatial processing in the right
Associated with working on geometric puzzles, navigation around familiar spaces, musical ability
Accuracy
Give the subject info and see how well they can hold onto it over time
Time (Reaction Time)
When accuracy is virtually perfect, because events occur over time in the mind
Transcranial Magnetic Stimulation (TMS)
Briefly anesthetize certain areas of the brain
Repeated magnetic pulse used to stimulate or inhibit regions of the brain temporarily
Simulates a degree of brain damage
Helps to determine what parts of the brain do what
What cognitive operations are independent from each other
Brain Lesions
Examine a group with similar lesions (typically examine control group of patients with different lesions)
What cognitive operations are spared/affected
Examine a group of individuals with similar cognitive impairment
Examine the brain regions common to this deficit
Neuroanatomy Imaging Techniques
Computerized Axial Tomography (CAT)
Magnetic Resonance Imaging (MRI)
Computerized Axial Tomography (CAT)
Highly focused beam of x rays passes through the body from many angles
Differing densities of organs deflect the rays differently, allowing visualization
Results in 9-12 ‘slices’ of the brain each taken at different level of depth
Recent hemorrhages identified by blood, older brain damage by areas of cerebrospinal fluid
Static picture of the brain
Magnetic Resonance Imaging (MRI)
No exposure to radiation and permits clearer pictures than CAT
Radio waves cause centers of hydrogen atoms to align themselves, computers record and create a 3D image
People with pacemakers cannot have an MRI (electrical fields in pacemaker interfered with by MRI)
Static picture of the brain
Electroencephalography (EEG)
Can be used to detect states of consciousness
Electrodes on scalp detect continuous measure of brain activity
Magnetoencephalography (MEG)
Measures changes in magnetic fields generated by electrical activity of neurons
Magnetic equivalent of EEG
Gives more precise localization of brain activity than EEG
Event-Related Potential (ERP)
Measures area of brain’s response to a specific event (electrical activity)
Electrodes on scalp, presented with external stimuli, record brain activity from before stimulus to some time after
Don’t tell you exactly where activity is happening
Positron Emission Tomography (PET)
Inject radioactive compound (radioisotopes of carbon, nitrogen, oxygen, or fluorine)
Measure blood flow to different regions of brain (when area is active more blood flows to it)
Reconstruction of a picture of a brain, shows which areas are most active at different points in time
Variation of PET involves measures local metabolic changes instead of blood flow (uses fluorodeoxyglucose)
Single Photon Emission Computed Tomography (SPECT)
Technique to measure cerebral blood flow (similar to PET)
Doesn’t require some of the expensive equipment of PET
Functional magnetic Resonance Imaging (fMRI)
Blood has magnetic properties and becomes less magnetic farther away from the heart
Active brain regions show change in ratio of oxygenated vs not blood
Subtraction technique
Subtract a control state from a task state to determine the relative amount of activation in a brain region
Slow because measures the bi product of the electrical activity (must wait for neurons to consume oxygenated blood, then the slow inflow of new blood)
Blood oxygenation level dependent function (BOLD)
Measures the properties of oxygenated vs deoxygenated blood
Slower than you’d expect (for other metabolic measures too)
