lecture 7: neuroanatomy

• The brain is composed of neurons that communicate using a mixture of chemical and electrical signals
• Neurons link together into circuits to allow us to sense and interact with the outside world
• Organisms have goals related to survival and reproduction, needing to evaluate and interact with the environment to achieve these goals
• The brain collects information about the environment, processes it, and sends commands to the body to interact with the world to achieve certain goals
• The brain processes sensory information (inputs) and produces behaviors (outputs)
• The brain is a complex biological system that plays a crucial role in sensing and moving
• The brain is involved in processing various sensory inputs such as light, sound, touch, odors, tastes, voluntary and involuntary movements, somatosensation, energy, chemicals, internal states like hunger/thirst, emotion, hormones, and memories
• • Ipsilateral: same side
• Anatomical terms:

  • Anterior or Rostral: towards the nose or front of the head
  • Posterior or Caudal: toward the back of the head
  • Dorsal: top surface of the brain
  • Ventral: bottom surface of the brain
  • Medial: towards the midline
  • Lateral: away from the midline
  • Coronal, Sagittal, Horizontal: anatomical planes
  • Nucleus (nuclei): collection of cell bodies in the CNS
  • Ganglion (ganglia): collection of cell bodies in the PNS
  • Afferent: incoming axons/information towards an area
  • Efferent: outgoing axons/information away from an area
  • Contralateral: opposite side
• Meninges:

  • Dura mater: thick outer layer surrounding the brain
  • Arachnoid membrane: web-like membrane between the dura mater and the pia mater
  • Pia mater: thin membrane that clings closely to the brain
  • Subarachnoid space filled with cerebrospinal fluid (CSF)
• Brain vasculature:

  • Brain has a network of blood vessels delivering oxygenated blood
  • Brain uses about 15% of total cardiac output
  • Blockage of vessels can lead to strokes
• Cerebrospinal fluid:

  • Necessary molecules are pulled from blood vessels and made available to neurons through CSF
  • Brain has large caverns filled with CSF (ventricles) that surrounds all cells
• Cerebral cortex:

  • The brain's wrinkled surface is called the cortex or cerebral cortex
  • Ridges are gyri and valleys are sulci
  • Divided into four lobes: frontal, parietal, occipital, and temporal
  • Association cortex plays a role in sensory processing and motor control
  • Frontal lobe contains the motor cortex and prefrontal cortex, important for planning, decision-making, and emotional control
  • Phineas Gage's case highlighted the PFC's role in impulse control, decision-making, and personality
• Parietal lobe:

  • Collects information from sensory systems, mostly somatosensation
  • Works with the prefrontal cortex to evaluate situations and make decisions
  • Damage to this lobe can result in sensory issues and hemispatial neglect
  • Stimulation of this lobe can produce sensations in different body parts
• Occipital lobe:

  • Devoted to vision
  • Humans heavily rely on vision, resulting in a well-developed visual system
  • Damage and electrical stimulation can reveal the importance of this lobe in processing visual information
• Temporal lobe:

  • Contains regions for sensory processing, primary auditory cortex, and additional visual areas
  • Medial temporal lobe contains regions essential for long-term memory, including the hippocampus
  • Hippocampus is crucial for forming long-term memories
• Medial temporal lobe:

  • Contains the hippocampus, essential for long-term memory formation
  • Also includes the amygdala, important for emotional processing and behaviors
• Thalamus:

  • Located in the center of the brain, ventral to the cortex
  • Acts as a sensory relay to the cortex, organizing incoming sensory information
  • Various nuclei in the thalamus act as gatekeepers for sensory information
• Hypothalamus:

  • Located under the thalamus, controls the autonomic and endocrine systems
  • Organizes behaviors related to survival, including fighting, fleeing, feeding, and mating
  • Pituitary glands release hormones into the bloodstream under the control of the hypothalamus
• Brainstem:

  • Composed of midbrain, pons, and medulla
  • Responsible for controlling essential functions like breathing, heartbeat, and sleep
  • Various nuclei in the brainstem produce modulatory neurotransmitters such as dopamine, serotonin, and norepinephrine
• Cerebellum:

  • Composed of two hemispheres densely packed with neurons
  • Important for the motor system, involved in movements requiring timing information and complex movement patterns
• The brainstem consists of the medulla oblongata, pons, midbrain, and diencephalon (thalamus).
• The cerebral cortex is divided into four lobes: frontal, parietal, occipital, and temporal.
• The cerebellum is located at the base of the skull.