psychology 101 chapter 3: neuroscience

Composition of Neuron

cell body, dendrites, axon, myelin sheath, glial cells, synapse

Cell Body

largest component of neuron, coordinates info processing and keeps cell alive. Contains nucleus and is the site for protein synthesis, energy production, and metabolism. Enclosed by the cell membrane

Dendrites

receives info from other neurons and communicates the message to cell membrane

Axon

carries info from other neurons, muscles, or glands

Myelin Sheath

insulating layer of fatty material that covers the axon

Glial Cells

“support cells” of the nervous system that can perform multiple tasks, such as digesting parts of dead neurons and forming MYELIN for the myelin sheath

Sensory Neurons

receives info from outside world and sends info to the brain through the spinal chord. Contains dendrites that receives signals for light, sound, touch, taste, and smell

Motor Neurons

carries signals from spinal chord to muscles to produce involuntary movement. Has long axons that reach to muscles

Interneurons

connects sensory, motor, or other interneurons with each other

Purkinje cells

interneuron that carries info FROM cerebellum TO rest of the brain and spinal chord

Pyramidal Cells

found in the cerebral cortex, integrate and process sensory information, transmit signals over long distances, and play a key role in learning and memory through synaptic plasticity

Bipolar cells

sensory neuron found in the retina of the eye. They transmit signals from light detecting cells and send that signal to the brain via the optic vein

STRUCTURE OF THE BRAIN, location and functions

Hindbrain: nearest to spinal chord, controls basic function for life like respiration, alertness, and motor skills

Midbrain: sits on top of brain stem, involved in motor controls, sensory processing, and sleep-wake. Contains Tectum and Tegmentum

Forebrain: highest and largest part of the brain, controls complex cognitive, emotional, sensory, and motor functions. Has two parts; cerebral cortex and subcortical structures

Brain weight

1,300-1,400 grams (3 pounds)

medulla (hindbrain)

an extension of the spinal chord into skull that takes care of heart rate, circulation, and respiration

reticular formation (hindbrain)

a small cluster of neurons inside medulla and extending upwards. Regulates sleep-wake and levels of arousal

cerebellum (hindbrain)

large structure of hindbrain that controls motor skills (like riding a bike), small replica of large brain and helps refine behaviour by smoothing out actions into graceful movements

tectum (midbrain)

helps make sense of stimuli (auditory and visual) by PROCESSING the body’s response

tegmentum (midbrain)

RESPONDS to stimuli by coordinating movement

subcortical structures (forebrain)

parts of cerebral cortex that is found under cerebral cortex and near centre of brain

includes thalamus, hypothalamus, basal ganglia, lymbic system

Thalamus (subcortical structure)

receives info from senses (touch, taste, sound) and sends that info to cerebral cortex. Closes sensory pathways so sleep is more peaceful.

hypothalamus (subcortical structure)

regulates hunger, thirst, and sexual behaviour. Regulates basic behaviours like keeping body temp, blood sugar levels, metabolism at an optimal functioning rate

Limbic System

a group of forebrain structures that are all involved in motivation, emotion, learning, and memory. (includes hypothalamus subcortical structure)

Hippocampus (limbic system)

makes NEW memories and connects to a network of knowledge so it can be stored into cerebral cortex

Amygdala (limbic system)

forms emotional memories by attaching emotional significance to stimuli. Ex: developing a fear of rats after seeing a dead one filled with maggots

Basal Ganglia (limbic system)

multiple subcortical structures that directs intentional movements and is involved with reward processing

Endocrine System

network of GLANDS that produce and secretes chemical messages into hormones, working closely with nervous system to regulate emotions, thoughts and behaviours

Pituitary gland (endocrine system)

“master gland” that releases hormones that direct what other glands do

Endocrine System flow

Signal, neurons transmits signal to hypothalamus, hormonal signals are transmitted to pituitary gland, pituitary gland releases more hormonal signals to send to other glands.

Cerebral cortex (forebrain)

highest level of brain that regulates the most complex aspects of perception, emotion, movement, and thought. Seen as a wrinkled “mushroom cap” that protects underside and stem

Gyri

raised parts of cortex

Sulci

indentations of cortex

Left and right hemispheres

Controls functions for the opposite side of body: contralateral control. Hemispheres are connected by commissures; bundles of axons that help communicate back and forth from each other

ex. right hemisphere perceives stimuli and controls movements on left side of body

Occipital lobe (within hemispheres)

Back of the cortex and processes visual info.

Starts with sensory receptors in eyes, sending info to thalamus, which sends info to occipital lobe. Occipital then extracts features from the stimuli like location and orientation to create a specific map of stimulus. This allows for comprehension of what’s being seen

Parietal lobe (within hemispheres)

processes info about touch. Contains the somatosensory cortex and is adjacent to the motor cortex

Somatosensory cortex (within parietal lobe)

represents the skin areas of the contralateral surface of the body and maps onto a specific part of the body. The more sensitive a body area is, the more it takes up space physically and involved it is.

Motor cortex (adjacent to parietal lobe)

initiates voluntary movements and sends msgs to basal ganglia, cerebellum, and spinal chord

Temporal Lobe

responsible for hearing and language, contains the primary auditory cortex

Primary auditory cortex

receives sensory info based on frequency of sounds, which turns into units of understanding like speech and words

Frontal Lobe:

in charge of movements, abstract. thinking, planning, memory, and judgement. Contains motor cortex and coordinates thought processes that connects information and retrieves memory

association areas

neurons that help make sense of info in cortex i.e. “that is horizontal, that is vertical, or that is a face." They integrate different types of sensory input for comprehensive perception.

mirror neurons

a neuron that activates when one watches a human/animal perform a behavior. Most activated when behavior has a context and is associated with understanding others' actions and intentions.

brain plasticity

ability for brain to adapt to changes in sensory inputs

ex: losing a middle finger would cause the somatosensory are responsible for middle finger neural communication to respond to stimulation from fingers NEXT TO middle finger

Gray Matter

cell bodies of neurons

white matter

white because of the myelin in axons, which means its higher in fat content

Blood-brain barrier

separation of the body and brain, keeps out disease that is in the body from reaching the brain. Keeps out body’s immune system as well- has its own

schwann cell

only myelanates 1 axon in peripheral nervous system outside the spinal chord

oligodendrocyte

have branches that mylenate SEVERAL axons within central nevous system (within spinal and brain)

astrocyte

maintains env. of synapse, talks and listens to neurons

channels

allow passive diffusion- no energy required, nature moves it along

pumps

allow active diffusion- push ions using an ATP, much more detailed

reverse polarity

flips from negative to positive in a split second and is the main form of brain communication. Reversal phrases; rising, repolarization, hyperpolarization