Brain and Behavior Midterm 1

brain

organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals

behavior

an organism’s activities in response to external or internal stimuli

computational level

• what is the problem being solved?

• goal of behavior

• ex: vision

  • the problem: convert patterns of light on the retina into objects in the world

  • the brain must compute edges, depth, motion, and object identity

algorithmic level

• what representations and rules solve the problem?

• information processing

• ex: vision

  • algorithms might include edge detection, motion detection, feature integration

implementation level

• how is the algorithm implemented?

• neurons, circuits, synapses

• ex: vision

  • retina —> LCN1 —> V1 —> higher visual areas

  • orientation selective neurons in V1

Jean Pierre Flourens and Karl Lashley

• rat maze experiments - performance deficits were proportional to the size of the lesion, but not the location

• the brain acts as a single functional unit

Paul Broca

• patients with the same language deficit has legions in same specific part of cortex

• responsible for speech fluidity

• localization of brain function

Phineas Gage

• lost all inhibition and became impulsive

• pole through the frontal lobe

Patient HM

• hippocampus scooped out

• seizures went away, but memories could not be formed

peripheral nervous system

• autonomic and somatic nervous system

central nervous system

• brain and spinal cord

autonomic nervous system

• controls self regulated action of internal organs and glands

• involuntary

• includes sympathetic and parasympathetic nervous system

somatic nervous system

• controls voluntary movements of skeletal muscles

• voluntary

efferent impulses

• motor

• information that comes back from the spinal cord to move the skeletal muscles

afferent impulses

• sensory

• what is going from the external surroundings to the spinal cord

sympathetic nervous system

• threat, anxiety, arousal

• heart racing, pupil dilation, sweating

• flight or fight

parasympathetic nervous system

• safe and relaxing

• pupil constriction, slow HR, breathing rate

• rest and digest

short S-M loops through spinal cord

unconscious reflexes

long S-M loops through cortex

conscious perception, goal directed behavior

stroke

• blood flow is cut off from the brain, turning it white

• neurons die due to lack of oxygen

epidural anesthesia

• used to numb a certain part of the body

• block signals to the brain —> pain perception

reticularists

neurons are connected to each other and form a sheet of connections, in which connections move through the sheet

neuronists

there are individual neurons that are the functional unit

neuron doctrine

conduction takes place in the direction from dendrites to the soma, to the end arborizations of the axon

neurotransmitters

• glutamate

• GABA

• acetylcholine

• serotonin

• dopamine

astrocyte

• help hold neurons together

• transport glucose from blood to neurons

• receive glucose from capillaries and break down into lactate, lactate is released into extracellular fluid that surrounds every neuron

• blocks most harmful substances from entering the brain

microglia

• immune cell of the brain

• functions:

  • axonal tract development

  • programmed cell death (phagocytosis)

  • synapse formation and pruning

  • responses to injury and immune challenge

oligodendrocyte

• wraps myelin around the axon —> allows information to travel long distances without leaking

• nodes of ranvier: breaks in myelin sheath which allow neurons to make contact with axon so axon can make contact with other neurons along the way

• lose myelin —> multiple sclerosis

multiple sclerosis

• information processing becomes difficult and the brain cannot effectively control the body parts

ions

an atom or molecule with a net electric charge due to the loss or gain of one or more electrons

biological membrane

charge separator

sodium potassium pump

• creating a biological battery

• pump sodium out of cell and potassium into cell

ion channels

• allow passive flow of ions down electrochemical gradient

• limits the rate by which each ion can flow across the membrane

• once channels open, K+ will rush out, or Na+ will rush in

diffusion

high concentration —> low concentration until evenly distributed

electrostatic pressure

opposites attract

action potential

• transient depolarizing spike of the membrane potential

• peak is +40

soups

• pre synaptic neuron

• soup is diffusing from the pre synaptic cell into the post synaptic cell

• electrical information getting converted into a chemical and becoming electrical again in the post synaptic cell

spark

• direct electrical current from pre synaptic cell to post synaptic cell

Otto Lowei’s Dream Experiment

• two isolated frog hearts in fluid chambers chemically connected

• heart has intrinsic rhythmicity

• heart with one intact vagus nerve (part of the parasympathetic nervous system)

• heart 1 slowed down and reduced amplitude of contraction

• heart 2 behaved like heart 1, proving a chemical mediator

excitatory postsynaptic potential (EPSP)

• graded depolarization

• NT binds and opens channels allowing Na+ or Ca2+ influx

inhibitory postsynaptic potential (IPSP)

• graded hyperpolarization

• NT binds and opens channels allowing Cl- or K+ efflux

drugs of abuse

reverse the transporter

excitatory neurons

• release of NT glutamate leads to depolarization (Na+ enters through ion channels)

inhibitory neurons

• release of NT GABA leads to hyper polarization (Cl- enters through ion channels)

downstream neuron

• listening in to all these different neuron types, integrating input to decide whether to fire an action potential

ionotropic

ion channels that allow + or - charged ions to pass through membrane

metabotropic

all kinds of biochemical cascades

frontal lobe

• decision making and planning

• personality and behavior

• voluntary movement

• speech production

parietal lobe

• process sensory information

• spatial awareness and body position

temporal lobe

• hearing and auditory processing

• memory

• language

occipital lobe

• vision and visual processing

cerebellum

• coordination and balance

• fine motor control

• motor learning

brainstorm

• controls automatic functions like breathing, heart rate, and digestion

• connects brain to spinal cord

limbic system

• hippocampus: memory formation and learning

• amygdala: emotions

• hypothalamus: regulates hunger, thirst, hormones, body temperature

thalamus

• relays sensory information to the cortex

basal ganglia

• movement control and habit formation