Ways of Studying the Brain
Accidents, Lesions, EEG, CAT, PET, MRI, Functional MRI
Region of brain is damaged and behavior is observed.
Ex: Phineas Gage
Deliberate removal or destruction of part of the brain. *Not for experimental purposes, but for treatment.
Ex: Hemispherectomies, Frontal lobotomies
Electrodes detect electrical activity in the brain. Different wave patters = sleep, epilepsy, relaxation, and mental concentration. Stimulation of given area = specific sensations
X-ray cameras are used to make detailed 3D images of brain. *Shows structure, not function, used to detect abnormalities
Measures glucose used in certain tasks, harmless radioactive glucose used for "tracing"
Uses magnetic fields to measure density and location of brain material. *Shows structure, not function
Shows detailed structure with info on blood flow. Allows researchers to link structure with brain activity and cognitive tasks.
3 Major Sections
Hindbrain, Midbrain, and Forebrain
Major parts of brain perform different and overlapping tasks
In cases of injury, certain structures take on new tasks
Consists of structures in the top part of the spinal cord, controls basic biological functions that keep us alive.
Regulates blood pressure, heart rate, and breathing.
Connects all three sections, involved with facial expressions.
"Little brain", stuck to the underside of brain. Coordinates voluntary movement and balance. Damaged in people with autism.
Located above the spinal cord and hindbrain, still below areas of forebrain. Small in humans. Coordinates simple movements and sensory info. Contains reticular formation: nerve network in the brain stem, controls arousal, if not functioning coma results.
Starts in midbrain extends into forebrain, body movement and generation of speech. Damaged in those with Tourette's Syndrome
Ventral Tegmental Area (VTA)
Involved in reward, motivation, cognition, and drug addiction.
Deeper parts of cerebrum called "diencephalon", upper region called "telencephalon"
Thalamus, Hypothalamus, Amygdala, and Hippocampus
Located on top of brain stem, responsible for sensory signals, sends signals to appropriate areas in brain. *Smell is only sense not relayed through the thalamus
Below thalamus, metabolic functions, body temperature, libido, hunger, thirst, and endocrine system.
Near front of brain. Controls arousal, regulation of emotion and initial reaction to sensory information.
Storage of new information in memory, formation of new memories
Deals with emotion and memory. (Thalamus, Hypothalamus, Amygdala, and Hippocampus)
Cannot form new memories
Can form new memories
Upper forebrain, when born the C.C. is full of neurons that are not connected yet. Development and growth = dendrites of neurons growing and connecting
Connects both hemispheres (bundle of fibers)
Brain lateralizations/ Hemisphere specialization
Specialization of each hemisphere
People without a corpus callosum
logic/reasoning, numbers/math, language/grammar, right hand/movement.
Spatial construction, nonverbal imagery, face recognition, intuition, imagination and creativity, left hand/movement
Frontal, Parietal, Temporal, and Occipital (both have left/right side)
Any areas not associated with sensory or movement control
Complex, sophisticated thoughts
40% of cerebral cortex, abstract thoughts and emotional control.
Sends signals to muscles and controls our voluntary movements
Anterior Cingulate Cortex (ACC)
Controls empathy and emotion
Located behind frontal lobe, contains somato-sensory cortex that receives incoming touch sensations from rest of body. Involved with math and spatial skills.
Motor and Somato-sensory cortices
Organized similarly, top receives sensations from bottom of body and vice versa
Back of brain, farthest from eyes. Major function: to interpret messages to visual cortex. Impulses from the right half of each retina are processed in the visual cortex in the left occipital lobe and vice versa. (Contra-lateral)
Processes sound sensed by our ears, sound waves processed by ears, turned into neural impulses, and interpreted in our auditory cortices. Auditory cortex NOT lateralized like visual cortex. Olfactory (smell) interpretation, allows one to recognize faces.
Interprets written and spoken speech. Damage to area affects ability to understand language.
Productive and receptive (loss of speech) *Not permanent due to plasticity of the brain
Inability to recognize faces
System of glands that secrete hormones that affect many different biological processes in our bodies.
The endocrine system is controlled by what part of the brain?
"master gland": growth and homeostasis. Located at the bottom of hypothalamus
Involved in sleep-wake cycle, fight or flight responses, and sexual development. (Receives signals from SCN in hypothalamus)
Produce adrenaline, which signals the rest of the body to prepare for fight or flight
Hormone that regulates daily biological rhythms and promotes sleep. Controlled by pineal gland, inhibited by light
Genetically identical twins, develop when a single fertilized egg splits in two
Fraternal twins, develop from separate fertilized eggs
Study of 100 identical twins that were adopted and raised in different families
The proportion of variation among individuals that we can attribute to genes
Missing genes on chromosome 7, missing genes for elastin. Skills: social, language, music. Disabilities: math and spatial skills.
Born with extra chromosome on 21st pair, rounded face, shorter fingers and toes, slanted eyes set far apart, different extents of mental retardation
Autosomal (not a sex chromosome). Dominant disease located on 4th chromosome, onset in 30s and 40s. Symptoms: involuntary movements, loss of motor control, loss of memory, slurred speech, swallowing problems, and decreased mental capacity
Phrenology (Franz Gall)
Bumps on head dictate personality/intelligence.
Jean Martin Charcot
Established 1st major school for neurology, focused on hysteria and hypnosis, 1st to scientifically describe multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS)
Santiago Ramon Y Cajal
Established a laboratory in Madrid for neurology, famously made very accurate drawings of brain cells
Individual nerve cells, make up entire nervous system, made up of discrete parts, human brain contains billions of neurons
Input fibers that carry electrical signals into neuron from connected cells (like antennae), receives message from as many as 10,000 other nerve cells and transfer them throughout the body
Cell body (SOMA)
Control center of neuron, integrates inputs from all dendrites, determines whether a neuron should fire or transmit a message to other neurons
Output fiber, carries electrical signals from a neuron to a neighboring cell
Layer of fatty tissue, covers around the axon, enables greater transmission speed of neural impulses as impulse jumps from one to the next, composed of glial cells, supports, nourishes and protects neurons
Threshold of excitation
For communication to occur, a cell must reach a certain level of stimulation
Brief electrical charge that travels down the axon as it becomes depolarized due to movement of positively charged ions entering the axon
Return to resting state of slight negative charge.
2 Major types of neurotransmitters
Excitatory (excite the next cell into firing), Inhibitory (impedes the next cell from firing)
Regulates mood, eating, sleeping and arousal. Prozac and ecstasy increase levels
Regulates movement and posture, linked to pleasure, lack thereof is associated with Parkinson's disease, an overabundance is associated with schizophrenia and Tourette's. Amphetamines and cocaine increase levels
Regulates muscle action, cognitive function and memory, nicotine increases levels
Regulates alertness and wakefulness, high levels linked with mania, low levels linked with depression (similar to dopamine)
Linked to hippocampus, loss of memories
Inhibits the action of the target cell, low levels: implicated in anxiety and epilepsy, alcohol and barbituates increase levels
"morphine within", natural, opiate-like neurotransmitters linked to pain control and pleasure
Most abundant excitatory neurotransmitter, plays significant role in learning and memory
Somatic nervous system
Consists of nerves that are connected to sensory receptors and to skeletal muscles that permit voluntary action, associated with all body movement
Peripheral nervous system
Consists of nerves and tissues outside of brain and spinal cord. Divided: Somatic and Autonomic
Autonomic nervous system
Controls body's response to stress (Fight or flight)
Sympathetic nervous system
Mobilizes body to respond to stress, accelerates heart rate, blood pressure and respiration, but conserves resources. (Accelerator)
Parasympathetic nervous system
Responsible for slowing down our body after a stress response. (Brake pedal)
Delusion in which an individual believes that a friend or family member has been replaced by an identical-looking impostor
Survivor of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior—effects
Mapped out the brain
First person to describe and study Autism
First to describe aspergers