1.04 The Brain

Cerebral Cortex

Outer layer of the brain

How many lobes are in the cerebral cortex?

4

Wernicke’s area

Located near left temporal lobe, important for language comprehension (interpreting what has been said)

Damage to this area (Wernicke’s aphasia) disrupts one‘s ability to comprehend language, but leaves one ‘s ability to produce words intact

frontal lobe (location)

Directly behind forehead and above the eyes

temporal lobe (location)

near the ears

parietal lobe (location)

directly behind frontal lobes at the top of the head

occipital lobe (Location)

In the back of each hemisphere

primary visual cortex

located behind the eyes, aids in interpreting visual information

temporal lobe (significance/job)

processes auditory information and memory

frontal lobe (significance/job)

plays a major role in executive functions: decision making, judgement formation, reasoning, personality, language

Broca’s area

located in the left frontal lobe; one of the most crucial areas of the brain for language production, if damaged, causes Broca’s aphasia

Broca’s aphasia

language disorder that affects how someone comunicates

Parietal lobe(significance/job)

vital for processing sensory signals from body (touch, pain, pressure, temperature)

somatosensory cortex

an area of the parietal lobe that is mapped to show where the signals from each body part are received

What are the Primary structures of the brain stem

medulla oblongata, the pons, the midbrain, the cerebellum, and the reticular formation

medulla oblongata

responsible for maintaining heart rate, respiration, digestion. Damage to this area results in death.

pons

located above the medulla is responsible for sending information from brain stem to cerebellum and cortex

midbrain

located above pons and involved in vision, hearing ,movement, and muscle coordination 

reticular formation

a network of nerve fibers carrying messages between different parts of the brain stem. It also helps in directing your attention to certain stimuli and away from others.

reticular activating system (RAS)

responsible for regulating sleep-wake cycle; if damaged, leads to irreversible coma

What parts does the limbic system include?

thalamus, hippocampus, amygdala, hypothalamus

thalamus

switchboard station between the brain stem and the cortex

hippocampus

plays vital role in processing information to long term memories and recall of facts and events from our lives. (How to remember: “you’ll never forget seeing a hippo on campus!”)

Damage to this impairs memory and cognitive issues.

Amygdala

processes information (emphasis in fear and anger), is more active in situations involving a potential threat

Hypothalamus

works with other brain parts to regulate the autonomic nervous system; controls the pituitary gland (endocrine system), which controls key hormones that regulate responses to stimuli

lateral hypothalamus

Regulates hunger

ventromedial hypothalamus

tells us when we are full (not hungry anymore)

left hemisphere (active)

more active when people engage in language and cognitive skills

right hemisphere (active)

More active when people engage in spatial and creative tasks

Corpus callosum

the connection between the two hemispheres of the brain

split brain

when corpus callosum is severed, the two hemispheres act independently of each other. Neuroscientists Roger Sperry and Michael Gazzaniga and their research on split brain demonstrated the lateralization of each hemisphere and roger sperry was awarded the obel prize in 1981

Neuroplasticity

the ability of the brain to reorganize neural pathways (if right hemisphere is lost, left hemisphere gains abilities lost by left hemisphere)

Plasticity is stronger in children than in people of old age.

Phineas Gage

case study in 1848:

An iron rod was sent through his skull due to complications in work, and he lost his left eye and 11% of his frontal lobe.

This caused a change in personality and was unsuccessful in finding another job. Researchers believe that this loss affected impulse control and decision making.

brain scans

one of the most common methods of learning about the structures and the activity of the brain

x-rays

show bones and other solid structures in the body

electroencephalogram (EEG)

measures electrical activity in the brain through use of electrodes placed around scalp

Uses: can show brain wave activity and is useful in sleep research

Magnetic resonance imaging (MRI)

Imaging technique that uses magnetic field and radio waves to generate detailed images of soft tissue in the body, including brain tissue. Helps diagnose strokes, tumors, or other disorders involving soft tissue injury

functional magnetic resonance imaging (fMRI)

Imaging technique that shows blood flow and oxygen levels to infer brain activity in certain areas of the brain (by showing where blood is showing in the brain)

CAT scans (computerized axial tomography

Takes two dimensional photographs that can then be turned into a three dimensional representation of the brain. This shows brain areas that are damaged and those receiving less blood flow, allowing scientists to detect tumors or concussions

PET scans (positron emission tomography)

use radioactive tracer molecule injected into a person’s bloodstream and processed in the same manner as glucose. This allows doctors to determine the amount of energy the brain uses for certain activities but can also be used to detect and diagnose illnesses

Lesioning

destroying part of a brain/removing tissue damaged from surgery to determine how function is affected