Brain and Behavior - Last Section of Info for Exam 1

cerebral cortex

thin outer layer of the brain, composed of neurons and glial cells; the gray matter

identifying the cerebral cortex in an image

the darker portion of the sulci and gyri near the surface of the brain

white matter (inside)

some glial cells, but mostly made up of myelinated axons from the cortex (myelin on the axons gives it the white color)

layers of the cortex

6 layers that become more distinguishable/developed/separated as people get older

central sulcus

center divider where the motor cortex is in front and the somatosensory cortex is behind it

anatomy act of 1832

allowed researchers to legally dissect the dead bodies of people other than criminals

motor cortex

controls motor movement by mostly sending efferent signals from the brain to the body

somatosensory cortex

responsible for our sense of touch by mostly receiving and processing afferent info

nerves in the motor and somatosensory cortexes

the more nerves and space an area has the more control or sense the corresponding part of the body has

betz cells

neurons with VERY long axons which extend from the motor cortex all the way down to the spine, where they synapse with the muscle-controlling circuitry of the spinal cord

pain in the brain

no pain receptors in the brain, but you can still feel pain in your brain/head because of the pain receptors in the surrounding tissues

frontal cortex

responsible for higher-level thinking, planning, associations, and inhibitions; helps manage our natural/instinctual desires

damage to the frontal cortex

causes disinhibition and impairments in attention, self-monitoring, memory-related retrieval strategies, and planning

disinhibition

inability to regulate or filter your speech and behavior

majority of brain injuries

frontal cortex injuries because humans are forward-moving creatures

damage sequence when we hit a fixed object head on

the brain rams forward, causing a coup injury, and then rebounds to hit the back of the brain, causing a contrecoup injury

frontal lobe contusion

bruising and bleeding in the brain at the sites of the coup and sometimes contrecoup injuries

most common cause of frontal lobe damage

traumatic brain injury (TBI)

symmetry in the brain

brains are structurally symmetrical, but not functionally symmetrical

cerebral (Yakolevian) torque

even though structurally the brain mostly has midline symmetry, there are slight structural differences between the hemispheres that make it look like there is a bending or warpage that twists, or torques the brain in a counterclockwise direction

structural differences of the brain pointed out by cerebral torque

in most people, the right frontal lobe extends forward slightly beyond the left, and the left occipital lobe extends slightly farther back than the right

valence hypothesis

in most animals, the left hemisphere is associated with positive emotions and the right hemisphere is associated with negative emotions

functional brain symmetry through evolution

throughout evolution, the brain has always been pretty functionally asymmetrical in humans and other mammals

paw preference in dogs

illustrates functional asymmetry in the brain because most male dogs are left-handed/pawed

tail movement in dogs

illustrates functional asymmetry in the brain because the right hemisphere pushes the tail to the left when the dog interprets something as a threat

illustration of functional asymmetry in the brain of wild horses

they act more aggressively toward potential threats coming from their left side

left gaze bias (LGB)

the right hemisphere controls the recognition of faces, so when we try to recognize a face, our eyes unconsciously linger more on what appears on our left side (the person's right side) of their face (both humans and some animals)

development of left gaze bias in humans

humans are not born with it, it develops in the first year of life

faithful reproduction

our brains have evolved to convince us that we use the information impinged on us to create a perfect, accurate model of the world in our heads

distorted reconstruction

the model of the world we make in our heads is actually a distorted reconstruction because it is only based on the evidence that impinges on us (a small portion of the whole picture)

distal stimulus

any object or event that exists or happens in the world that is not part of me

percept (2)

the conscious model of the world that we make created in the sensory receptors; the end result of the process of perception

proximal stimulus

the coding of the distal stimulus and the pattern of electrochemical changes in the sensory receptors in response to the distal stimulus

the coding that occurs in the proximal stimulus

the electrochemical changes in the sensory receptors that code a baseline layer of information before sending the information further into the brain for more intense processing

photopigments in rods and cones

convert electromagnetic energy into chemical signlaing

the process of light entering the eye

it enters through the pupil, is focussed by the lens, and the projected onto sensory receptors (rods and cones) in the retina

pupil

where the light enters the eye at the center of the iris

the lens

focusses light and the pupil by reshaping itself and projecting light back onto the sensory receptors (rods and cones) on the retina

fovea

center of the retina with the most densely packed cones

the optic nerve

transmits visual electrical impulses from the retina to the visual cortex

cones transmitting info

each cone feeds to 1 bipolar cell, which then feeds it to 1 ganglion cell (1:1:1 arrangement)

foveal vision (w/ cones)

has better visual acuity (sensitivity to detail) because of the 1:1 cone:bipolar cell ratio

periphery

mostly rods which have less visual acuity than cones

rods transmitting info

lots of rods feed into 1 or 2 bipolar cells

peripheral vision (w/ rods)

has better sensitivity in low-level lighting, partly because each bipolar cell is collecting info from so many rods

ganglion cells transmitting info

once the ganglion cells receive the info from the bipolar cells, they send that info via their axons back to the optic nerve

layers of the retina as you get further back in the eye

axons of ganglion cells, ganglion cells, bipolar cells, photoreceptors (rods and cones) at the back

blind spot

the spot in the back of the eye where the optic nerve is because there are no rods or cones in that spot

how we compensate for our blindspot

the brain goes through a computationally complex process of filling in the spot that we can't see (we do this unconsciously)