Brain Response Behavior

Neurons

Neurons communicate by receiving messages from electrical processes through the dendrites. The dendrites receive “incoming messages from other neurons and transmit them to the cell body” (Morris & Maisto, 2005, p. 48). The nerve impulse releases neurotransmitters to send the message to other parts of the body by the synapse. The synapse has a small area so the neurons can send messages but do not touch each other. The synaptic cleft is a small space located between the axon terminal and the dendrite of the receiving neuron.

Transmitting Messages

The axon terminal carries “outgoing messages to neighboring neurons or to a muscle or gland” (Morris & Maisto, 2005, p. 48). The pre-synaptic neuron sends messages to the post-synaptic neuron through the synaptic cleft. The pre-synaptic axon terminal contains synaptic vesicles filled with neurotransmitters. Some vesicles release chemicals when a neural impulse reaches the pre-synaptic terminal. The molecules are released, crossing the synaptic cleft and moving to the post-synaptic dendrite. Receptor sites and neurotransmitter molecules must have the same shape so they can transmit information. The neurotransmitter molecules and the receptor sites bind together, transmitting information from one neuron to the next.

Neurotransmitters

Each neurotransmitter has a positive or negative effect on nerve circuits. Neurotransmitters either help or hinder communication between the nerve impulses. A combination of excitatory, a helper, and inhibitory neurotransmitters, a hinder, is essential to balance communication in the nerve circuits. An imbalance of the neurotransmitters can cause physiological and mental illness.

The following is a list of some of the more common neurotransmitters in the brain and the function the neurons have on the brain according to Morris and Maisto (2005):

Acetylcholine (Ach) – affects arousal, motivation, attention, movement, memory; neurons connect through muscle cells, affecting muscle action; linked to Alzheimer’s and paralysis.

Dopamine – affects movement, memory, emotions, and learning; linked to Parkinson’s and schizophrenia.

Serotonin – affects pain, sleep, mood, dreaming, and eating habits; linked to depression.

Endorphins – affects pain, or the inhibition of pain; released during strenuous activity.

Norepinephrine – affects memory, mood, arousal, learning, and wakefulness.

Gamma amino butyric acid (GABA) – linked to the central nervous system and affects eating and sleeping disorders; low levels are linked to high anxiety.

Glutamate – effects the perception of pain and long-term memory (Morris & Maisto, 2005, p.54).

Regions of the Brain

The brain is the most complex body part made up of over a million neurons and cells in each region. The brain has three major regions; the central core, the limbic system, and the cerebral cortex that contains the right and left hemispheres. Each part of the brain controls various functions of the body. Within each region of the brain, are smaller parts that control memory, emotions, behavior, movement, comprehension and thoughts, and vision. An imbalance in just one part of the brain can cause psychological or physical disabilities.

Functions of the Brain

The central core includes the medulla, pons, cerebellum, thalamus, and the hypothalamus. Information is transported from one area to another. The medulla is close to the spinal cord and controls the function of blood pressure, heart rate, breathing, and respiration. Chemicals are reproduced near the medulla in the pons that control the wake-sleep cycle. Balance and movement are controlled by the cerebellum, which is at the back of the brain stem. The midbrain is above the cerebellum and is necessary for seeing and hearing. It also registers pain in the midbrain.

According to Morris and Maisto (2005), “The thalamus is often described as a relay station: Almost all sensory information from the lower parts of the central nervous system passes through the thalamus on the way to higher levels of the brain.” The hypothalamus is below the thalamus. The hypothalamus controls many functions such as thirst and hunger to sexual drive and body temperature. Another portion of the hypothalamus controls emotion and motivation.

The Nervous System

The limbic system is between the cerebral hemispheres and the central core and includes the hippocampus and the amygdala. The limbic system coordinates “the activity of the nervous system” and plays an important “role in times of stress” (Morris & Maisto, 2005, p. 62). Both the hippocampus and amygdala regulate emotions. The hippocampus is in control of forming new memories. The cerebral cortex is comprised of the occipital lobe, temporal lobe, parietal lobe, and the frontal lobe.

The cerebral cortex “processes thought, vision, language, memory, and emotions” (Morris & Maisto, 2005, p. 62). Within the cerebral cortex are convolutions which are unique in every person. The cerebral cortex is divided into sections; the left and right hemispheres which are divided into four lobes. The lobes contain association areas which control learning, remembering, comprehension, and thinking.

Listed are the association areas and their functions.

Frontal lobe - coordinates and receives messages from other lobes of the cortex. The frontal lobe is also involved in motivation, character, personality, moral decision making, and persistence (Greene & Haidt, 2002); important for attention and emotion.

Primary motor cortex - controls movement, sends messages to the glands and muscles.

Central fissure - separates the primary cortex and the somatosensory cortex.

Primary somatosensory cortex – a section of the frontal lobe that registers messages from the body.

Parietal lobe – controls spatial abilities and receives sensory information from receptors throughout the body

Temporal lobe – involved in emotion regulation, visual tasks, and balance

Occipital lobe – controls visual information

Right hemisphere – controls the left side of the body; movement, visual, nonverbal, and spatial tasks.

Left hemisphere – controls the right side of the body; movement, language, and symbolic reasoning.

Corpus callosum – allows communication between the right and left hemispheres (Morris & Maisto, 2005).

Sensory Information

The senses the player uses are vision, hearing, and touch. According to Morris and Maisto (2005), “Almost all sensory information from the lower parts of the central nervous system passes through the thalamus.” The brain transmits information from what it sees, hears, and feels to other parts of the brain that tell yet other parts how to respond, react, and perceive information. Sensory information is sent to both hemispheres. Both hemispheres communicate with each other, back and forth, to relay messages from one part of the brain to another.

The player tracks the ball with his eyes and watches the ball hitting the bat. The cerebral cortex of the brain, particularly the parietal, temporal, and occipital lobes, processes and transmits the visual information. The association areas are “areas of the cerebral cortex where incoming messages from the separate senses are combined into meaningful impressions and outgoing messages from the motor areas are integrated” (Morris & Maisto, 2005, p.63). When the ball and bat come in contact, the player hears the cracking sound. The hearing portion of the brain is controlled by the temporal and parietal lobes, sending messages to other parts of the brain. The midbrain also processes information for sight and hearing. The frontal lobe assists with goal-directed behavior, such as following the ball after the bat hits it. Motor projection is also controlled by the frontal lobe, allowing the player to track the location of the ball.

Sensory Information

The primary somatosensory cortex of the brain registers sensory messages. “Somatosensory cortex receives sensory messages from the entire body, from the primary motor cortex, which sends messages from the brain to various muscles and glands in the body” (Morris & Maisto, 2005, p. 63). The sensory messages are sent to the parietal lobe, which receives the information. The parietal lobe is responsible for the sense receptors throughout the body, such as muscles and joints. This part of the brain allows the player to track the ball and move in a position to catch the ball.

References

C.G. Morris and A.A. Maisto. (2005). Psychology: An Introduction. Prentice-Hall. Twelfth Edition.

C. Morris and A. Maisto. (2002). The Biological Basis of Behavior. Live psych 2.2 Neurons and Neural Impulses. Pearson Education Company.

C. Morris and A. Maisto. (2002). The Biological Basis of Behavior. Live psych 2.3 The Synapse and Neurotransmitters. Pearson Education Company.