> Brain cells fire in pattern
> Brains have coronal views
The brain:
● Part of CNS
● Made of neurons (lots of neurons, ~86 billion neurons)
○ They make information possible to travel (see textbook)
○ They have more parts and information travels through those parts in the following
order after synapse
1. Dendrite
2. Cell body
3. Axon (has myelin around it which helps the signal travel faster
through the axon)
4. Node of ranvier
5. Axon terminals
○ They have synapse (it helps to transmit information - the neuron to receive is
postsynaptic, the one to send is presynaptic)
○ Transmit information by firing action potential (release chemicals)
■ Every neuron has a firing threshold
■ The all-or-nothing principle: an action happens or not depending if the
threshold is met
● It takes time for neurons to do things
○ The longer the distance, the longer it takes to travel; about ~ 120 m/s
● Organized in parts
○ Corpus callosum (connects the two hemispheres)
○ Left and right hemispheres
○ Cortex
○ Cerebellum (motor function, behind the brain)
■ Cerebellar Ataxia is the damage to the cerebellum which causes
difficulties in walking, speech and movement
○ Lobes
■ Frontal lobe (thought, planning)
■ Occipital lobe (vision)
■ Parietal lobe (spatial, touch)
■ Temporal lobe (hearing, memory)
● Different parts have specialized functions
○ First time realized by Broca when he found the Broca’s area which is responsible
for speech
■ Broca’s aphasia is the damage of Broca’s area - nonfluent expression,
difficulty finding words
● Different parts communicate with each other and with the rest of the body
● Has gray matter(cell bodies) and white matter (myelin-coated axons)
● Brain organization is not random
, ● The brain changes across lifespan
○ Plasticity: a property of the brain that allows it to change due to injury or
experience
■ The brain can recover from injury due to plasticity
Nervous system:
● Central Nervous System (CNS): is the core of the body
● Peripheral Nervous System (PNS): goes around the body
● A nerve is a bundle of neurons that allow the brain and the body to communicate
Perception and Sensation
● Sensation (the detection and transmission of information about external stimuli to the
brain)
○ Sensory coding = the stimulus of a sensation is transduced into chemical and
electrical signals
● Perception
○ Stimulus (Sound wave) (Light waves)
○ Receptors (Hairs on ear - cochlea) (Retina)
○ Nerve (Auditory nerve) (Optic nerve)
○ Brain (Thalamus) (Thalamus)
● From eyes to brain
○ Light waves
○ Cornea
○ Pupils
○ Retina (Light is organized in it upside down)
■ Rods (detect brightness)
■ Cones (detect color)
● When there is not enough light they don’t have enough stimulation
■ Ganglion Cells (intermediary)
● 120 rods + 6 cones connected to one Ganglion Cell
● Receptive field - the part of the retina from which the Ganglion
Cell receives information from the photoreceptors
● Signals for GCs are inhibitory or excitatory
● ON-center/OFF-surround - stimulation from the center receptors is
excitatory and from around is inhibitory.
● OFF-center/ON-surround - similar to above
■ Optic Nerve (info goes to brain)
● Creates a hole in the retina, but we don’t have a hole in the vision
because we move our eyes constantly
■ Organized backwards
■ Fovea (has cones but not rods)
● Less sensitive to dim light
○ Thalamus
○ Primary visual cortices
■ Either hemisphere of the brain gets information from both eyes
> Brains have coronal views
The brain:
● Part of CNS
● Made of neurons (lots of neurons, ~86 billion neurons)
○ They make information possible to travel (see textbook)
○ They have more parts and information travels through those parts in the following
order after synapse
1. Dendrite
2. Cell body
3. Axon (has myelin around it which helps the signal travel faster
through the axon)
4. Node of ranvier
5. Axon terminals
○ They have synapse (it helps to transmit information - the neuron to receive is
postsynaptic, the one to send is presynaptic)
○ Transmit information by firing action potential (release chemicals)
■ Every neuron has a firing threshold
■ The all-or-nothing principle: an action happens or not depending if the
threshold is met
● It takes time for neurons to do things
○ The longer the distance, the longer it takes to travel; about ~ 120 m/s
● Organized in parts
○ Corpus callosum (connects the two hemispheres)
○ Left and right hemispheres
○ Cortex
○ Cerebellum (motor function, behind the brain)
■ Cerebellar Ataxia is the damage to the cerebellum which causes
difficulties in walking, speech and movement
○ Lobes
■ Frontal lobe (thought, planning)
■ Occipital lobe (vision)
■ Parietal lobe (spatial, touch)
■ Temporal lobe (hearing, memory)
● Different parts have specialized functions
○ First time realized by Broca when he found the Broca’s area which is responsible
for speech
■ Broca’s aphasia is the damage of Broca’s area - nonfluent expression,
difficulty finding words
● Different parts communicate with each other and with the rest of the body
● Has gray matter(cell bodies) and white matter (myelin-coated axons)
● Brain organization is not random
, ● The brain changes across lifespan
○ Plasticity: a property of the brain that allows it to change due to injury or
experience
■ The brain can recover from injury due to plasticity
Nervous system:
● Central Nervous System (CNS): is the core of the body
● Peripheral Nervous System (PNS): goes around the body
● A nerve is a bundle of neurons that allow the brain and the body to communicate
Perception and Sensation
● Sensation (the detection and transmission of information about external stimuli to the
brain)
○ Sensory coding = the stimulus of a sensation is transduced into chemical and
electrical signals
● Perception
○ Stimulus (Sound wave) (Light waves)
○ Receptors (Hairs on ear - cochlea) (Retina)
○ Nerve (Auditory nerve) (Optic nerve)
○ Brain (Thalamus) (Thalamus)
● From eyes to brain
○ Light waves
○ Cornea
○ Pupils
○ Retina (Light is organized in it upside down)
■ Rods (detect brightness)
■ Cones (detect color)
● When there is not enough light they don’t have enough stimulation
■ Ganglion Cells (intermediary)
● 120 rods + 6 cones connected to one Ganglion Cell
● Receptive field - the part of the retina from which the Ganglion
Cell receives information from the photoreceptors
● Signals for GCs are inhibitory or excitatory
● ON-center/OFF-surround - stimulation from the center receptors is
excitatory and from around is inhibitory.
● OFF-center/ON-surround - similar to above
■ Optic Nerve (info goes to brain)
● Creates a hole in the retina, but we don’t have a hole in the vision
because we move our eyes constantly
■ Organized backwards
■ Fovea (has cones but not rods)
● Less sensitive to dim light
○ Thalamus
○ Primary visual cortices
■ Either hemisphere of the brain gets information from both eyes
