Neurotransmitters are chemical agents enclosed at the end of axons of nerve cells that diffuse across the synaptic gap and transmit information to neighboring cells. In layman’s terms, cells use these neurotransmitters to communicate with each other. Six important neurotransmitters are Acetylcholine, Serotonin, Norepinephrine, Dopamine, GABA, and Endorphins.

1)     Acetylcholine is a chemical transmitter, found in both the Peripheral Nervous System and Central Nervous System, which allows neurons to communicate with each other within humans and other organisms. 

2)     Serotonins are neurotransmitters found in CNS of animals. They are involved in sleep, depression and memory.

3)     Norepinephrine acts as a drug, it will increase blood pressure, trigger physical arousal and affect learning and memory. They are synthesized from dopamine and also function as a neurotransmitter and as a stress hormone.

4)     Dopamine is also a neurotransmitter and hormone associated with movement, attention, learning, and the brain’s pleasure. Insufficient formation and action of dopamine can cause Parkinson’s disease.

5)     GABA (Gamma-Aminobutyric Acid) is a neurotransmitter found in the nervous systems of widely divergent species. GABA helps balance and offset excitatory messages from neurons.

6)     Endorphins are chemicals manufactured by the brain, which are released in response to stress or trauma and used to reduce the perception of pain.

The cerebral cortex is made up of four lobes; the frontal lobe, parietal lobe, temporal lobe, and occipital lobe. The cerebral cortex is involved in many complex brain functions including memory, attention, perceptual awareness, “thinking”, language, and consciousness.

1)     The frontal lobe is located at the front of the brain and is associated with reasoning, motor skills, higher lever cognition, and expressive language. At the back of the frontal lobe, near the central sulcus, lies the motor cortex. This area of the brain receives information from various lobes of the brain and utilizes this information to carry out body movements.

2)     The parietal lobe is located in the middle section of the brain and is associated with processing physical sensory information such as pressure, touch, and pain. A portion of the brain known as the somatosensory cortex is located in this lobe and is essential to the processing of the body’s senses.

3)     The temporal lobe is located on the bottom section of the brain. This lobe is the location of the primary auditory cortex, which is important for interpreting sounds and the language we hear.

4)     The occipital lobe is located at the back portion of the brain and is associated with interpreting visual stimuli and information. The primary visual cortex, which receives and interprets information from the retinas of the eyes, is located in the occipital lobe.

The limbic system is a system of functionally related neural structures in the brain that are involved in emotional behavior. Some of the structures of the limbic structures are the Amygdala, Hippocampus, Hypothalamus, and Thalamus.

1)     The amygdala is nuclei involved in emotional responses, hormonal secretions, and memory.

2)     The hippocampus acts as a memory indexer sending memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieving them when necessary.

3)     The hypothalamus directs a large number of important functions. It’s the structure that wakes you up in the morning, and gets the adrenaline flowing. The hypothalamus is also an important emotional center, controlling the molecules that make you feel exhilarated, angry, or unhappy.

4)     The thalamus are cells that relay sensory signals to and from the spinal cord and the cerebrum.

Insomnia, sleep apnea, restless leg syndrome, and narcolepsy are all serious sleep disorders that have harmful health consequences. These disorders are very common and can result from a number of causes like stress, illness, alcohol intake, and medications. People who work at night are at an increased risk of all these problems including emotional and mental problems too. In most cases, the darkness of the night triggers sleepiness. That’s why night shift workers often experience sleep disorders, because they cannot sleep when they start to feel drowsy. Their biological clock tells their body to sleep while they are engaging in work. Depression is also a factor for sleep disorder, where the patient wakes up in the middle of the night and cannot go back to sleep. Chemical changes in the body caused by diseases or medications can also be a result in sleeping difficulties. 

The material I found most challenging in these chapters were to collect and memorize the characteristics and the many different types of neurotransmitters and their functions. I studied most of this portion in the textbook itself. If I needed more information on the subject matter I would refer to the Internet, and mostly pages from Wikipedia.

The brains ability to function and structure is referred to as plasticity. Functional plasticity is the brain’s ability to move functions from damaged to undamaged brain areas. Structural plasticity is the brain’s ability to change its physical structure in response to its environment. One of the research evidences are the comparison of rats raised in bare laboratory cages and the ones who are brought up in enriched environments and groups. The rats that were raised in enriched environments showed significant increases in brain growth that the rats from the impoverished environments. Put into practical applications, studying enrichment studies have had a major force in shaping the nervous systems of animals abroad. This study proves that a mentally, stimulating, and intellectually challenging are associated with enhanced cognitive functioning.