Psych 100 Neuro Science

Nervous System

Coordinates its actions and sensory info by transmitting signals to and from different parts of the body. It detects environmental changes and works in tandem with the endocrine system to respond.

Central nervous system (CNS)

Consists of the brain and Spinal Cord

Peripheral Nervous System (PNS)

•consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body

The endocrine system

is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs, it can be considered as the chemical regulator of the body that consists of glands that secrete hormones.

A gland in the endocrine system is composed of

groups of cells that function to secrete hormones

A hormone

is a chemical that moves throughout the body to help regulate emotions and behaviours. 

Pituitary Gland (hypophysis)

secrets the growth hormone, regulates growth and controls the function of other glands

Pancreas (gland)

secrets insulin, controls the glucose levels in blood to keep the body supplied with fuel to produce and maintain energy source

Pineal Gland (epiphysis cerebi)

secrets melatonin, regulates the wake-sleep cycle

thyroid (gland)

secrets thyroxine, controls the metabolism rate (balanced growth)

Parathyroid (gland)

secrets parathormone, controls calcium balance in the body

adrenal (gland)

secrets adrenaline, prepares body for emergency

testes (gland)

secrets testosterone, controls growth and development in male reproductive systems

ovaries

secret estrogen, controls growth and devlopement in female reproductive systems

A neuron

is a cell in the nervous system whose function it is to receive and transmit information.

The nervous system contains how many neurons

around 100 billion

resting potential

•, a state in which the interior of the neuron contains a greater number of negatively charged ions than does the area outside the cell.

Describe the process of Action Potential

The electrical signal moves through the neuron as a result of changes in the electrical charge of the axon. When the segment of the axon that is closest to the cell body is stimulated by an electrical signal from the dendrites, and if this electrical signal is strong enough that it passes a certain level or threshold, the cell membrane in this first segment opens its gates, allowing positively charged sodium ions that were previously kept out to enter.

once action potential occurs

the number of positive ions exceeds the number of negative ions in this segment, and the segment temporarily becomes positively charged.

refractory period

a brief time after the firing of the axon in which the axon cannot fire again because the neuron has not yet returned to its resting potential.

explain the process of synapse

Within the neuron, when a signal is received by the dendrites, it is transmitted to the soma in the form of an electrical signal. If the signal reaches the terminal buttons, they are signalled to emit chemicals known as neurotransmitters, which communicate with other neurons across the spaces between the cells, known as the synaptic gap

A neurotransmitter

is a chemical that relays signals across the synapses between neurons

Different terminal buttons release different neurotransmitters, and different dendrites are particularly sensitive to different neurotransmitters

There are two effects neurotransmitters cause when are accepted by the receptors on the receiving neurons:

1.excitatory (i.e., they make the cell more likely to fire)

2. inhibitory (i.e., they make the cell less likely to fire).

Can a receiving neuron accept more than 1 neurotransmitter

The receiving neuron may be able to accept more than one neurotransmitter, it will be influenced by the excitatory and inhibitory processes of each

neurotransmitters can be broken down through which 2 methods

reuptake and through enzymes (being broken down)

reuptake

a process in which neurotransmitters that are in the synapse are reabsorbed into the transmitting terminal buttons, ready to again be released after the neuron fires.

define agonist and antagonist

•Agonist molecules increase a neurotransmitter’s action. Some agonists may increase the production or release of neurotransmitters, or block reuptake in the synapse. Other agonists may be similar enough to a neurotransmitter to bind to its receptor and mimic its excitatory or inhibitory effects.

•Antagonists decrease a neurotransmitter’s action by blocking production or release.

Acetylcholine (ACh)

A common neurotransmitter used in the spinal cord and motor neurons, to stimulate muscles contractions, its also used in the brain to stimulate memory, sleeping and dreaming. Alzheimers is associated with an undersupply of ACh, nicotine acts as an agonist.

Dopamine

Involved in movement, motivation and emotion, dopamine produces feelings of anticipation of pleasure when released by the brains reward system and its also involved in learning. Schizophrenia is linked to increased dopamine whereas parkinsons is linked with low (and can be treated with dopamine agonist)

Endorphins

Released in response to behaviours such as: vigorous exercise, orgasm, eating spicy foods. They are natural pain relievers,

Gabba (Gamma-aminobutyric acid)

The main inhibitory transmitter in the brain. A lack of it can result in involuntary motor actions including tremors or seizures. Alcohol stimulates the release of gamma which inhibits the nervous system and makes us feel drunk. Low levels can produce anxiety, gabba agonists can help treat anxiety.

Glutamate

The most common neurotransmitter, it is used in 90% of the brains synapses. It is found in the food additive msg, but it cannot influence nervous systems. Excess glutamate can cause migraines, seizures, and overstimulation.

Serotonin

Involved in many functions such as mood, appetite, sleep, aggression. Low levels are associated with depression

Norepinephrine

Helps control alertness and arousal. Undersupply can depress mood.

The medulla

the area of the brain stem that controls heart rate and breathing.

The pons

a structure in the brain stem that helps control the movements of the body, playing a particularly important role in balance and walking.

Running through the medulla and the pons is a long, narrow network of neurons known as the

reticular formation

reticular formation

Its job formation is to filter out some of the stimuli that are coming into the brain from the spinal cord and to relay the remainder of the signals to other areas of the brain. It also plays important roles in walking, eating, sexual activity, and sleeping.

The thalamus

is the egg-shaped structure above the brain stem that applies more filtering to the sensory information that is coming up from the spinal cord and through the reticular formation, and it relays some of these remaining signals to the higher brain levels. It also receives some of the higher brain’s replies, forwarding them to the medulla and the cerebellum. Its also important in sleep because it shuts off incoming signals from the senses, allowing us to rest.

The cerebellum

consists of two wrinkled ovals behind the brain stem. It functions to coordinate voluntary movement. It also contributes to emotional responses, helps us discriminate between different sounds and textures, and is important in learning

The limbic system

is a brain area, located between the brain stem and the two cerebral hemispheres, that governs emotion and memory.

It includes many structures, but the most important are the amygdala, the hypothalamus, and the hippocampus.

The amygdala

consists of two “almond-shaped” clusters, and is primarily responsible for regulating our perceptions of, and reactions to, aggression and fear. The amygdala has connections to other bodily systems related to fear, including the sympathetic nervous system, facial responses (which perceive and express emotions), the processing of smells, and the release of neurotransmitters related to stress and aggression.

The hypothalamus

is a brain structure that contains a number of small areas that perform a variety of functions, including the regulation of hunger and sexual behaviour, as well as linking the nervous system to the endocrine system via the pituitary gland. The hypothalamus helps regulate body temperature, hunger, thirst, and sex, and responds to the satisfaction of these needs by creating feelings of pleasure. 

Hippocampus

consists of two “horns” that curve back from the amygdala. The hippocampus is important in storing information in long-term memory. If the hippocampus is damaged, a person cannot build new memories

The pituitary gland = hypophysis

is an endocrine gland, about the size of a chickpea. Your pituitary gland is divided into two main sections: the anterior pituitary (front lobe) and the posterior pituitary (back lobe). Your pituitary is connected to your hypothalamus through a stalk of blood vessels and nerves called the pituitary stalk (also known as infundibulum).

The cerebral cortex

the outer bark-like layer of our brain that allows us to so successfully use language, acquire complex skills, create tools, and live in social groups.

corticalization.

In humans, the cerebral cortex is wrinkled and folded, rather than smooth as it is in most other animals. This creates a much greater surface area and size, and allows increased capacities for learning, remembering, and thinking. The folding of the cerebral cortex is referred to as

what do glial cells do

they support neurons by protecting them, providing nutrients and absorbing unused neurotransmitters. They maintain homeostasis, form myelin in the peripheral nervous system.

what are glial cells

are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses.

frontal lobe

(behind the forehead), which is responsible primarily for thinking, planning, memory, and judgment.

parietal lobe

which extends from the middle to the back of the skull and which is responsible primarily for processing information about touch. 

occipital lobe

at the very back of the skull, which processes visual information.

temporal lobe

responsible primarily for hearing and language. located on the lower side of each hemisphere, contains the auditory cortex, which is responsible for hearing and language.

the motor cortex

the part of the cortex that controls and executes movements of the body by sending signals to the cerebellum and the spinal cord.

the somatosensory cortex

an area just behind and parallel to the motor cortex at the back of the frontal lobe, receives information from the skin’s sensory receptors and the movements of different body parts.

the visual cortex

is the area located in the occipital lobe (at the very back of the brain) that processes visual information.

association areas

The remainder of the cortex is made up of __________ _____, in which sensory and motor information is combined and associated with our stored knowledge

Neuroplasticity

refers to the brain’s ability to change its structure and function in response to experience or damage.

Neurogenesis

is the process by which new neurons are formed in the brain.

electroencephalography or Eeg

is a technique that records the electrical activity produced by the brain’s neurons through the use of electrodes that are placed around the research participant’s head

Functional magnetic resonance imaging (fMRI)

is a type of brain scan that uses a magnetic field to create images of brain activity in each brain area. Neurons that are firing use more oxygen, and the need for oxygen increases blood flow to the area. The fMRI detects the amount of blood flow in each brain region, and thus is an indicator of neural activity.

Transcranial magnetic stimulation

is a procedure in which magnetic pulses are applied to the brain of a living person with the goal of temporarily and safely deactivating a small brain region. In TMS studies the research participant is first scanned in an fMRI machine to determine the exact location of the brain area to be tested. Then the electrical stimulation is provided to the brain before or while the participant is working on a cognitive task, and the effects of the stimulation on performance are assessed.

Positron emission tomography

is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption

Magnetoencephalography (MEG)

is a functional neuroimaging technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using very sensitive magnetometers. MEG provides a very accurate resolution of the timing of neuronal activity. This is a non-invasive test.

damages to the brain are called

lesions