An overview of the basic anatomy of a mammalian brain in relation to psychological testing and understanding, as well as functions of the areas. Unfortunately, mammals cannot take brain pills to help us to research their brain better.
There are a number of parts in a mammalian brain, many of which are used throughout the field of psychology to understand the brain’s role in various human behaviors.
The Spinal Cord
The spinal cord is seen at the base of the brain. It is the source of communication between the body and the brain. The spinal cord transports a variety of sensory information to the brain:
- Touch — This is the ability to notice something impinging on the body;
- Nociception — This is the ability to notice tissue damage and other harm done to the body through pain;
- Temperature — This is the ability to notice the degree of warmth or coolness of something; and
- Proprioception — This is the ability to know where we are in space based on information given from our muscles, such as how compressed or stretched they are.
The spinal cord synapses with the alpha motor neuron, which controls muscles. It then sends the information gathered above to the thalamus.
The spinal cord then connects to the medulla. The medulla is responsible for various life support mechanisms, and it basically determines whether the mammal is dead or alive. In the medulla is the vagus nerve, which handles the parasympathetic system and cardiovascular activity.
The medulla connects to the pons. The pons controls states of consciousness. It contains two specific areas:
- Raphé — This area handles global arousal and sleep-wake cycles. It projects to the forebrain and uses the neurotransmitter serotonin; and
- Locus Coeruleus — This area handles specific arousal, selective attention, and vigilance. It projects to the forebrain and uses the neurotransmitter norepinephrine.
Above the pons is the cerebellum. The cerebellum controls ballistic movement, or shot-out movement, without sensory feedback. It times muscle contractions and smoothes movements.
The Superior and Inferior Colliculus
The pons then connects to the midbrain, which contains three specific areas. Two of these areas are the superior colliculus and the inferior colliculus, which are located above the tegmentum. The inferior colliculus takes in auditory sensory information. The superior colliculus takes in visual sensory information. These areas also control head movement in response to sensory information – for example, if a mammal hears/sees something they turn towards it.
Attached to the pons is also the tegmentum, which is below the superior and inferior colliculus. The tegmentum is basically a continuation of the pons. It contains two specific areas:
- Substantia Nigra — This area handles motor control, or the ability to move. It projects to the basal ganglia and uses the neurotransmitter dopamine; and
- Ventral Tegmental Area — This area handles motivation, craving, wanting, etc. It is a seeking system that gives a mammal the will to move. It projects to the ventral striatum and uses the neurotransmitter dopamine.
The superior colliculus connects to the thalamus, which is located above the hypothalamus. The thalamus relays sensory information from the cortex, especially sensory information that is transmitted from the spinal cord and other areas.
The tegmentum connects to the hypothalamus, which is located beneath the thalamus. The hypothalamus controls homeostasis, or the maintenance of consistency in the mammal, especially as it relates to the internal body environment. The most common example of this is body temperature, which remains at a specific and constant degree.
The Basal Ganglia
The thalamus connects to the basal ganglia, which is located above the ventral striatum. The basal ganglia controls slow onset/offset ramp movements. This includes postural control, and is an involuntary muscle control region. Information from the substantia nigra is projected to the basal ganglia.
The Ventral Striatum
The ventral striatum connects to the hypothalamus and is located below the basal ganglia. Located here is the limbic system, which holds two specific areas:
- Hippocampus — This area is involved in memory, specifically short term memory and the storage/retrieval to long term memory; and
- Amygdala — This area controls emotions that are necessary for survival, such as fear and rage.
The final area of the brain is the cortex, which is nothing more than a thin sheet of cells that surrounds the above-mentioned structures. This sheet of cells is often folded and compacted to fit into a mammalian skull, producing the wrinkly look that is commonly known with brains.