BIO PSYCH 2

Brain Plasticity

brain’s ability to change and learn new things.

Apoptosis

Programmed mechanism of cell death.

Never Growth Factor (NGF)

Promotes the survival and growth of the neuron.

Fetal Alcohol Syndrome and its impacts

Fetal alcohol syndrome is when a mother heavily drinks alcohol when pregnant. This impacts the brain by causing problems such as impulsivity, ADHD, motor problems, etc.

Over production and pruning

Nervous system creates an excess of neural connections and then eliminates the unused ones to build efficient network.

Proliferation

(lasts 28 weeks gestation): Brain makes new cells

Migration

Cells move to target location

Differentiation

formation of axon and dendrites

Synaptogenesis

formation of synapses

Myelination

(slowest one. Doesn’t end until 30 years of age): A fatty covering forms around nerve fibers to help messages travel faster.

How can experience change the developing brain

Experience can excite certain neural circuits

-        Neural circuits used repeatedly strengthen, whereas those not used often weaken and are pruned.

Is the brain still plastic in old age?

Yes, the brain is still plastic. It is just less plastic than it was at a younger age.

No Transfer

you get better at the thing you practiced, but it doesn’t help with other tasks

Far Transfer

you practice one skill and get better at something different

Near Transfer

you practice something and get good at something similar.

Closed Head Injury

Sharp blow to the head that doesn’t puncture the brain.

-        Can cause damage at the moment of trauma (Primary)

-        Lasting effects (secondary)

Stroke

Loss of brain function due to disturbance in blood supply to the brain

Ischemia

blood clot or other obstruction closes an artery

o   tPA breaks up clots (only helps with ISCHEMIA not Hemorrhage)

o   Na+, Ca+, and Zn+ accumulate inside brain and kill  

Hemorrhage

artery rupture (fatal)

Diaschisis

decreased activity of surviving neurons after other neurons are damaged.

Sprouting

a change in axon

-        Collateral sprouting: a surviving axon grows a new branch to replace the synapses left vacant by the damaged axon.

Denervation supersensitivity

is when a nerve cell becomes extra sensitive because it loses the nerve signals it normally receives.

Cortical reorganization after brain damage

The brain changes its connections so other areas can help take over lost functions.

Deafferentation

when the brain loses sensory signals from a part of the body because the nerve connections are damaged or cut.

Distal senses

senses that detect things far away from your body, such as sight, hearing, and smell.

Proximal senses

senses that detect things through direct contact with your body, such as touch, taste, and feeling temperature.

A general pathway of sensory information processing

Energy in the world —> receptor —> sensory neurons —> Thalmus —> primary cortex —> association cortex

“Every Rabbit Seems To Prefer Apples”

Neural layers in the eye, connection order

Turns light into messages that travel to the brain

Rods and cones —> bipolar cells —> Ganglion cell —> Optic Nerve —> Brain

“Red Birds Gather On Branch”

Rod and ratio

Helps you see at night

Ratio: 120 million rods: 6 million cones per retina

Cone

Helps you see color and fine detail

Blind Spot

Area at a point that cannot be seen or perceived.

Trichromatic

Color perception occurs through the relative rates of response by 3 kinds of cones. (Photoreceptor cones)

-        Short wavelength —> Blue

-        Medium —> Green

-        Long —> Red

Opponent process theory

We perceive colors in terms of opposite pairs (Bipolar cells)

-        Blue and Yellow

-        Red and Green

-        Black and White

Retinix theory

eyes and brain recognize colors consistently, even when lighting conditions change.

Visual information Pathway

Photoreceptors —> Bipolar cells —> Amacrine cells and Ganglion cells —> Optic nerve —> Optic Chiasm —> LGN and Superior Colliculus —> Primary Visual Cortex (v1) —> Visual Association areas (V2-V5)

Contralateral processing

-        Left visual field —> right hemisphere

-        Right visual field —> left hemisphere

Lateral inhibition

A mechanism in which activity in one neuron reduces activity in neighboring neurons

-        its purpose in the visual system is to sharpen contrast and emphasize borders between light and dark areas

Receptive Field

The area of the visual field in which light stimulation or information affects a particular neuron.

Receptive field size affects the Hermann grid illusion.

Peripheral Vision

what you can see out of the corners of your eyes without looking directly at it.

Foveal Vision

seeing sharp, detailed images when looking directly at something

At an Intersection

Gray spots disappear when you look directly at them.

Three parallel pathways

P, M, K retina to LGN

Parvocellular (p)

(midget cell)(precision); detect color and fine detail. 4 layers of LGN

Magnocellular (m)

(parasol cell); detect movement and overall pattern. 2 layers of LGN

-        motion

Koniocellular (k)

(bistratiefield cell); help process some color and contrast. In between layers of LGN  

-        color and contrast

Primary visual cortex (V1)

receives information from LGN and is the area responsible for the first stage of visual processing located in the occipital lobe

Blindsight

-        People with blindsight seem to access some visual information but aren’t aware that they can.

caused by damage to V1

V5

motion perception. When V5 is damaged, akinetopsia happens, meaning motion blindness. E.g. doesn’t know when to stop pouring water into the cup until it spills.

Ventral pathway

-        what an object is

-        starts from occipital to temporal lobe

Dosal pathway

-        where an object is

-        starts from occipital to parietal lobe

difference between visual agnosia and general memory loss

In visual agnosia, they can recognize an object through sight but if they use their other senses, they will be able to recognize what object it is, whereas in general memory loss you wouldn’t be able to recognize what object it is no matter what senses are being used.

Apperceptive Agnosia

is posterior brain damage, Difficulty forming a clear visual representation of an object, has trouble copying or matching objects

Associative Agnosia

Anterior Brain damage, Can perceive the object's shape but cannot identify what it is, May be able to copy an object but cannot name or recognize it.

Fusiform Face card (FFA)

the region of the brain devoted to faces

Prosopagnosia

Face blindness

-        Facial identification difficulty

Greebles experiment

Shows that practice helps us recognize similar objects, like how we recognize faces.

Optic Ataxia

Difficulty reaching for objects accurately, even though the person can see them.

Auditory Receptor

Specialized hair cells located inside the cochlea of the inner ear. They convert mechanical sound waves into electrical neural signals that the brain perceives as sound.

Primary Auditory Cortex (A1):

The part of the brain that first processes sound.

• Location: Superior temporal lobe.

• Function: Helps you recognize basic sound features, like pitch, loudness, and tones.

Damadge to A1

Makes it harder to process sounds correctly, especially complex combinations of sounds.

Similarities and differences between auditory and visual processing

Both recognize patterns and objects, and both need experience to develop 

Auditory is sound and visual is recognizing objects
and images 

somatosensory cortex

In the parietal lobe processes body sensations like touch, pain, and temperature.

Receptor for pain and temperature

Free nerve endings detect pain, heat, and cold.

Synesthesia

when stimulation of one sense automatically triggers an experience in another sense

Bouba and Kiki effect

The brain connects certain sounds with certain shapes.

·       Bouba = round, smooth shape.

·       Kiki = sharp, spiky shape.

Bottom-up processing

The brain uses information from the senses to understand what it sees, hears, or feels.

Top Down Processing

The brain uses past experiences, knowledge, and expectations to understand sensory information.

Metalinguistic Awarness

better understanding of the structure and meaning of the language.

Focal hand dystonia

involuntary musical contractions, cramping, and abnormal posturing

Penumbra

area surrounding stroke site

How to perserve neurons

• remove blood clot

• block excitatory synapses

• block flow of Ca+ and Zn+

• cool the brain

Diaschisis

decreased activity of surviving neurons after other neurons are damages

Deaffrented

when the afferent (sensory) input is lost

• motor function perserves if the limb is necessary for a task