Morin The Brain

Brain lesion

Brain lesion

naturally/experimentally destroyed brain tissue to study animal behaviors after such destruction

Electroencephalogram (EEG)

Amplified recording of electrical waves across brains surface - measured by electrodes on scalp

non intrusive and painless

different colors of EEG

Blue is non-active area Red/orange shows activity

Magnetoencephalography (MEG)

a patient completes tasks and thousands of neurons create electrical pulses which create magnetic fields

speed and strength helps researchers understand how tasks influence brain activity

What are MEGs used for

surgical brain mapping

PET scan

you drink a sugary glucose liquid beforehand -- active neurons gobble glucose

visual display of brain activity that detects a radioactive form of glucose while the brain performs a task

MRI (magnetic resonance imaging)

uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of brain tissue

fMRI

uses magnetic fields and radio waves that distinguish brain tissue and shows the structures that are functioning

MRI vs fMRI

fMRI is a video it shows which structures are working MRI is a picture

MRI vs X-Rays

MRI shows ligaments, x-rays show bones

CT Scans

x-ray photos from 180 angles that create a cross-sectional image

Brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions

Medulla

base of brainstem - controls heartbeat and breathing

Reticular formation

a nerve network in the brainstem that plays an important role in controlling arousal

Pons

Sits directly above medulla Connects upper and lower part of the brain, controls dreams during REM stage

Thalamus

Sensory switchboard - directs messages to sensory areas in cortex, sends replies to cerebellum and medulla

at top of brainstem

What sense does the thalamus not process

Smell

Cerebellum

the "little brain" at the rear of the brainstem

coordinates voluntary movements and balance

limbic system

System of neural structures at border of brainstem and cerebrum

associated with fear, aggression, hunger, sex

Amygdala

Part of the limbic system - two almond-shaped neural clusters linked to fear and anger

Hypothalamus

Part of the limbic system, under thalamus

directs maintenance activities (eating, drinking, temperature, emotion), helps govern endocrine system w pituitary gland

4 F's Hypothalamus is responsible for...

Food, fight, flight, fornication

Two parts of hypothalamus

lateral hypothalamus and ventromedial hypothalamus

Hippocampus

forms, stores, processes memory

part of limbic system, (looks like a seahorse)

parts of the limbic system

Hypothalamus, amygdala, hippocampus

Cerebral Cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres

the body's ultimate control and information-processing center.

Four lobes of cerebral cortex

frontal, parietal, occipital, temporal

separated by prominent fissures

Frontal lobe

functions include planning, organizing, problem solving, "higher cognitive functions" - behavior and emotions

fully mature at 25

Prefrontal cortex

the frontmost portion of the frontal lobes - especially important for decision making

Back of the frontal lobe

pre-motor/motor areas -- motor cortex

Damage to the frontal lobe

Change in talking, mood, mental flexibility, socialization and behavior

IQ does not get impactd

Parietal lobe

processes sensory input/discrimination, body orientation

somatosensory cortex

registers and processes body touch and movement sensations

primary somatosensory cortex

area of the parietal lobe where messages from the sense receptors are registered

secondary somatosensory cortex

Region of cerebral cortex that analyzes information from the primary somatosensory cortex and thalamus;

Damage to the Parietal Lobe

disorientation of environment or parts of body, can't distinguish sensory stimuli

severe: can't recognize yourself

Occipital lobe

primary visual reception/association area - allows for visual interpretation

Damages to occipital lobe

hallucinations

temporal lobe

hearing and auditory interpretation -- damages cause hearing deficits

Homunculus

a maplike representation of regions of the body in the brain

shows how a person would look if it was proportionate to the amount of the brain that goes towards it -- lips would be biggest

aphasia

inability to speak

caused by damage to Broca's area or wernicke's area (both in left hemisphere)

Broca's area

left frontal lobe -- impairs speaking

specialized strip of neurons used for speech production

wernicke's area

left parietal/temporal lobe - impairs understanding

this typically allows you to comprehend the words people speak

angular gyrus

transforms visual representations into an auditory code - helps with reading

on temporal, parietal and frontal (TPF)

visual cortex

The visual processing areas of cortex in the occipital and temporal lobes.

receives written words as visual stimulation

Do you want an EEG to show brain activity

no because you can't isolate the different parts being used

which parts are used to hear words

auditory cortex and wernicke's area

Which parts are used to see words

visual cortex and angular gyrus

which parts are used to speak words

Broca's and motor cortex

association areas

areas of the cerebral cortex that are composed of neurons that help provide sense and meaning to information registered in the cortex -- they're multitaskers that have a lot of different info but aren't highly specialized

plasticity

the brain's ability to change -- decreases with age

what is the brain sculpted by

genes and experiences

Plasticity in sensory deficits

if there's a deficit neurons can go from one place to the other to help the body

EX: If you're blind neurons go to other senses

Plasticity with repeated behaviors

if you do something often enough (typically at a young age) association area neurons can become specialized

how is the brain controlled

contra-laterally left hem controls right side right hem controls left side

left hemisphere

reading, writing, speaking, math and comprehension skills

(Broca's and wernicke's are here)

right hemisphere

spatial abilities, face recognition, visual imagery, music

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

How to split the brain and why

cut the corpus callosum

if you have an epilepsy or a stroke or some storm in the brain cutting this protects it from spreading

how a severed corpus callosum impacts seeing objects

objects in the right visual sphere (processed by left) can be named but in the left they can't

optic nerves

the nerve that carries neural impulses from the eye to the brain

don't get severed when corpus is cut

divided consciousness post severed corpus callosum

the two sides of the brain have processed two different things

if you see heart the person would verbalize they saw "art" but with their left hand point to "he"

chimeric figures test

constructed of two half pictures arranged so that patients fixate upon the vertical division between the two half stimuli

tests which hemisphere is dominant & how a split brain patient processes things

how information is processed in non-split brains

two hemispheres share information through corpus callosum - work together

what factors influence handedness

genes/prenatal factors

what professions are lefties more prominent in

musicians, mathematicians, baseball players, architects, artists

how percentage of left handers is impacted by age

percentage decreases sharply in older people

The two types of nervous systems

Central nervous system and peripheral nervous system

Sensory Neurons (Afferent neurons)

carry nerve impulses from receptors/sense organs to CNS

tells the CNS what's happened

Motor Neurons (Efferent Neurons)

carry nerve impulses AWAY from CNS to muscles

tell the body what the CNS says

Interneurons

connect sensory and motor neurons, only exist in the CNS

Central Nervous System

Brain and Spinal cord

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

Consist of autonomic and somatic nervous system

Autonomic nervous system

controls self regulated actions of internal organs

Sympathetic and parasympathetic

Sympathetic nervous system

Arousing

Part of the autonomic nervous system (peripheral)

Parasympathetic nervous system

Calming

Part of the autonomic nervous system (peripheral)

Somatic nervous system

part of the peripheral nervous system

controls voluntary movements (deals with the body)

Nervous System

Consists of all nerve cells -- speedy electrochemical communication system

Examples of what the autonomic nervous system controls

breathing, blinking, heartbeat, digestion, salivation, sweating, arousal

When does the sympathetic nervous system activate

in stressful situations it arouses the body and mobilizes its energy

When does the parasympathetic nervous system activate

in calming situations it calms the body, conserving its energyt

Does the spinal cord feel things (pain, pleasure, etc)

No, this all comes from the brain

Can the parasympathetic and sympathetic nervous system work together?

no, when one is on the other is off

Amyotrophic Lateral Sclerosis (ALS - Lou Gehrig's disease)

"No muscle nourishment" - progressive degeneration of motor neurons affecting nerve cells in brain and spinal cord

when motor neurons die the brain can't initiate/control muscle movement -> can lead to total paralyzation

The Endocrine System

the body's "slow" chemical communication system

How does the endocrine system communicate

carried out by hormones synthesized by a set of glands

Hormones

chemicals synthesized by the endocrine glands and secreted in the bloodstream -- affect the brain and other tissues o the body

Epinephrine (adrenaline)

increases heart rate, blood pressure, blood sugar, excitement during emergency situations

Pituitary Gland

"master" gland has an anterior and posterior

Anterior pituitary gland

Releases hormones that regulate other glands

Posterior pituitary gland

Regulates water and salt balance

Thyroid Gland

Affects/regulates metabolism

Dendrites

Branchlike parts of a neuron that are specialized to receive information.

Soma/the cell body

contains the cell nucleus, connected to dendrites

Nucleus

Axon

the extension of a neuron, ending in branching terminal fibers

Myelin Sheath

Insulates axon, helps the speed of neural transition

Nodes of Ranvier

Terminal buttons/buds

Neurotransmitters are here

Terminal branches