defines neuroscience as:

“The study of the brain and nervous system, including molecular neuroscience, cellular neuroscience, cognitive neuroscience, psychophysics, computational modeling and diseases of the nervous system.” lists it as:

“The study of how the nervous system develops, its structure, and what it does. Neuroscientists focus on the brain and its impact on behavior and cognitive functions. Not only is neuroscience concerned with the normal functioning of the nervous system, but also what happens to the nervous system when people have neurological, psychiatric and neurodevelopmental disorders.

That’s dense…

Perhaps most simply, neuroscience is the study of how the nervous system, in particular the brain, causes us to sense, calculate, and act

Here we have a helpful, simplified breakdown of the nervous system (NS)

Let’s start with the central nervous system (CNS), composed of the brain and spinal column. The central nervous system scans around using our senses (touch, see, feel, taste, hear). This information gets sent to the brain by the spinal column. The brain then which decides what information is important. It then creates a response, which is sent back to relevant bod parts, via the spinal column. This all happens in a flash.

Generally speaking, there are three regions of the human brain

  1. Forebrain 
    1. Diencephalom
    2. Telecephalon
  2. Mesencephalon (midbrain)
  3. Hindbrain
    1. Myelencephalon
    2. Metencephalon

There is still debate as to some of the regions of the brain and where they fit in. As such, more generally, there are perhaps two main regions in the brain:

  1. Forebrain
    1. Telencephalon
    2. Diencephalon
  2. Brain stem
    • Hind brain
    • Mesencephalon

Brain stem

    • lower and more ancient
    • automatic functions


  • Myelencephalon (aka medulla, or, medulla oblongata)
    • arousal
    • sleep
    • attention
    • movement
    • cardiac function
    • respiratory function
  • Metencephalon
    • Pons
      • extremely important for breathing
      • regulates taste
      • movements, posture, balance
    • Cerebellum
      • voluntary movement
      • reflex memory
      • fine movement
      • timing
      • aspects of cognition
      • language

Midbrain (or, mesencephalon)

  • Ventral tegmental area
    • executive function
    • part of the reward pathway of the brain
  • Tectum
    • has two pairs of small bumps, called colliculi, on it
    • Inferior colliculi (back pair)
      • auditory functions
    • Superior colliculi (front pair)
      • visual functions
  • Tegmentum
    • Periaqueductal gray 
      • pain reduction processes
    • Substantia nigra
      • sensorimotor activity
    • Red nucleus 
      • sensorimotor activity



  • Thalamus
    • relays sensory information to the sensory cortex
    • perception
    • attention
    • timing
    • movement
    • alertness
    • awareness
    • memory
    • consciousness
    • cognition
    • perception
  • Hypothalamus
    • eating
    • sleeping
    • sex
    • thirst
    • arousal
    • body temperature
    • sweating
    • blood pressure
    • heart rate
    • shivering
    • circadian rhythm
    • controls hormone release from the pituitary gland
    • some consider it part of the diencephalon


  • recently evolved
  • Cerebral commissures (fibre bundles connecting various brain regions)
    • Corpus collosum, main one – information passage between right and left brain

      • Limbic system
        • Amygdala
        • Hippocampus
        •  Nucleus accumbens
        • Cingulate gyrus
        • Septum
        • highly indicated in mental illnesses
        • regulates emotion and expression
        • plays a role in our capacity to learn
        • impulse control
        • basic motivations
        • memory formation
        • memory storage
        • smell processing
        •  thirst
        •  hunger
        •  sex
        • aggression
        • seat of emotion processing
        • memory
        • the main region involved in pleasure
        • central to addiction
      • Basal ganglia
        • Striatum (also known as caudate putamen)
        • Globus pallidus
        • Caudate nucleus
        • planning motor activity
        • initiating motor activity
        • learning skills
        • reflexes
        • walking
        • muscle tone control
        • reward
        • arousal

Related image

  • Cerebral cortex
    • made of four lobes in each brain hemisphere, totalling eight lobes
    • responsible for our great intelligence
    • Left hemisphere
      • cognitive processes
    • Right hemisphere
      • perception
    • Temporal lobe
      • recognizing sights and sounds
      • perception (smell, hearing, vision)
      • learning
      • long-term memory
      • language comprehension
      • emotion
    • Parietal lobe
      • preecption of sensory information
      • integration of sensory information
      • processing visuospatial elements
      • number representation
      • spatial attention
      • spatial mapping
      • monitoring body position
      • attention to space
    • Occipital lobe
      • vision
    • Frontal lobe
      • Prefrontal cortex
      • makes sense of information
      • making decisions
      • voluntary behavior
      • planning
      • thinking
      • problem-solving
      • control of voluntary movement
      • cognition (in general)
      • intelligence
      • attention
      • language comprehension
      • language processing
      • heavily involved in mental illness

Image result for limbic system drug addiction

Such is the central nervous system. Moving on! The peripheral nervous system ensures that the body is undergoing its proper functions. Its general components are discussed.

  • Somatic nervous system
    • controls muscles
    • relays sensory information to the central nervous system for evaluation, then transmits orders back to muscles
  • Enteric nervous system
    • causes reflexes
    • moves muscles that aid in digestion
    • evaluates various internal conditions
  • Autonomic nervous system
      • causes reflexes
      • moves muscles that aid in digestion
      • evaluates various internal conditions
      • preserves a stable internal state (homeostasis)

    Image result for autonomic nervous system

    • aids in digestion
    • regulates body temperature
    • pumps oxygen, nutrients, hormones, and waste via blood cells to and from the body (cardiovascular system, or, circulatory system)
    • Endocrine system
      • quite interconnected with the immune system
      • physical disorders related to stress
      • Adrenal gland
        • produces adrenaline
        • produces hormones that regulate salt levels
      • Pituitary gland
        • controls development
        • regulates other glands
        • can receive information from hypothalalmus to send to adrenal gland to make cortisol (hypothalamic-pituitary-adrenocotical axis, or, HPA axis)
        • implicated in mental illness
      • Thyroid gland
        • produces thyroxine, which also regulates growth and metabolism of energy
      • Gonadal gland
        • sex hormones
    • Sympathetic nervous system
      • swiftly mobilizes organs and glands during great stress
      • faster heartbeat=more fuel to muscles
      • increased respiration=the body has more oxygen
      • adrenal gland is stimulated=”fight or flight” response
    • Parasympathetic nervous system
      • calms the body after stressor passes

Working together:

Sources: Abnormal Psychology: An Integrative Approach, Uppers, Downers, All Arounders: Physical and Mental Effects of Psychoactive Drugs,, Dr. Kevin Davis, Biopsychology, 3-D Brain (app),,,,,