Neuroscience: Brain Structures and Functions

Question to Ponder

• Why do we have a brain?

Week 5, Oct 28th - Nov 3rd

• Two in-person lectures (Monday & Wednesday)
• Read Week 5 readings on Canvas
• Complete Quiz 4 on Canvas by Sunday at 11:59 pm
• Quiz available at 5 pm on Wednesday
• Optional: Attend a ULA session
• Optional: Participate in Week 5 Discussion by Sunday at 11:59 pm
• TAs can review exam questions but cannot access exam or grade

Week 5 & 6 Tutoring Sessions

• Structured sessions: sheep brain neuroanatomy
  • Thursday, October 31st, 2-3 pm with Leia & Xi (Psych East 3834)
  • Friday, November 1st, 2-3 pm with Uma & Sukari (Psych East 3834)
  • Tuesday, November 5th, 5-6 pm with Joey & Grace (Psych East 3834)
  • Thursday, November 7th, 4-5 pm with Leia & Xi (Psych East 3834)
  • Friday, November 7th, 1-2 pm with Uma & Sukari (Psych East 3834)
  • Friday, November 7th, 2-3 pm with Joey & Grace (Psych East 3834)
• Drop-in sessions
  • Monday, October 28th, 5-6 pm with Grace & Uma (Library 4572)
  • Wednesday, October 30th, 5-6 pm with Grace & Sukari (Library 4574)
  • Thursday, October 31st, 12-1 pm with Joey & Leia (Transfer Student Center)
  • Friday, November 1st, 11-12 pm with Xi and Joey (ONDAS Student Center)

Unit 2

• Unit 1: The brain is composed of neurons that communicate to one another using a mixture of chemical and electrical signals
• Unit 2: How do neurons link together into circuits to allow us to sense and interact with the outside world?
• What is the purpose of a brain?
  • Organisms have a variety of goals, largely related to survival and reproduction—need to evaluate the environment and interact with it to accomplish these goals

Sensing and Moving

• Organisms have a variety of goals, largely related to survival and reproduction—need to evaluate the environment and interact with it to accomplish these goals
• Inputs (sensory information) → brain → output (behavior)
• The brain collects information about the environment, processes it, and sends commands to the body to interact with the world in order to achieve certain goals

Sensing and Moving (details)

• Light, Sound, Touch, Self (body), Proprioception, Olfaction, Gustation, Odors, and Taste
• Internal state: Hunger/thirst, Emotion, Hormones, and Memories → Voluntary & Involuntary Movements

Goals of the Second Unit of This Course

• Unit 1: The brain is composed of neurons that communicate to one another using a mixture of chemical and electrical signals
• Unit 2: How do neurons link together into circuits to allow us to sense and interact with the outside world?
• Week 5/6: Focus on vision as an example of how external information gets processed by various elements of the nervous system (more on the other senses in weeks 6 and 7)
• Week 7: How do signals in our brain result in the movement of our body to interact with our environment?

Todays Topics

• 7A: Getting into the Brain
• 7B: Cerebral Cortex
• 7C: Everything but the Cortex

Week 5 Takeaways

• Use anatomical terms to describe the location of brain regions
• Label key regions of the brain, including cortical lobes and subcortical areas
• Explain methods to gain information about how different brain regions contribute to behavior
• Describe the brainstem components and their roles in brain function and behavior
• Identify brain regions responsible for creating and releasing neurotransmitters (dopamine, serotonin, norepinephrine)
• List the major components of the visual system
• Describe the overall anatomy of the retina, including cell layers and important features
• Compare and contrast rods and cones
• Describe the transduction mechanism for light

Introduction to Biopsychology (Fall 2024)

• Lecture 7A: Getting into the Brain

Goals of This Section

• Define key anatomical terms for navigating the brain
• Describe the three layers of meninges that surround the brain

Anatomical Terms

• Anterior/Rostral (toward the nose)
• Posterior/Caudal (toward the back of the head)
• Dorsal (top surface)
• Ventral (bottom surface)
• Medial (toward the midline)
• Lateral (away from the midline)
• Midline

Anatomical Terms (details)

• 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
• Ipsilateral: same side
• Anatomical planes: coronal, sagittal, horizontal

Types of Matter

• Visually, brain tissue appears as either gray matter or white matter.
• Gray matter contains cell bodies of neurons.
• White matter consists largely of long-range projections (axons) with white color from fatty myelin.

Meninges

• Brains are delicate; need protection and oxygen delivery.
• Meninges: layers protecting the brain
  • Dura mater: thick outer layer surrounding the brain
  • Arachnoid membrane: web-like membrane between the dura and pia mater
  • Pia mater: thin membrane clinging to the brain

Brain Vasculature

• Intricate network of blood vessels delivers oxygenated blood (15% of total cardiac output).
• Blockage can lead to strokes.

Cerebrospinal Fluid

• Necessary molecules get pulled from blood vessels to neurons through CSF, regulated by astrocytes.

Cerebrospinal Fluid (details)

• Brain has large caverns filled with CSF (ventricles).
• CSF also surrounds all cells.

Introduction to Biopsychology (Fall 2024)

• Lecture 7B: Cerebral Cortex

Goals of This Section

• Identify visible features on the brain's surface
• Describe the four lobes of cerebral cortex and their functions

Surface of the Brain

• Wrinkled surface of the brain is known as the cortex or cerebral cortex.
• Ridges are gyri, and valleys are sulci.
• Four lobes:
  • Frontal (rostral to the central sulcus)
  • Parietal (caudal to the central sulcus)
  • Occipital (caudal to the parietal lobe)
  • Temporal (ventral to the sylvian fissure)

Divisions of Cortex

• Different areas of the cortex are involved in various functions.
  • Motor areas
  • Sensory areas
  • Association areas

Association Cortex

• Much of the human cortex is for higher-level functions.
• Primate brains have more association cortex compared to smaller, "simpler" brains.

Frontal Lobe

• Main controller for voluntary movements (motor cortex)
• Prefrontal cortex (PFC), crucial for planning, decision-making, and emotional control.
• Humans have a highly developed PFC (takes longer to mature).

Phineas Gage

• Head impaled by a railroad spike, destroying a large chunk of his prefrontal cortex.
• Survived but experienced significant personality and behavior changes.
• Highlighted the PFC's role in impulse control and decision-making.

Parietal Lobe

• Responsible for collecting sensory information, particularly from body senses (somatosensation)
• Involved in combining sensory info; works with the PFC to evaluate situations and make decisions.

Parietal Lobe (additional info)

• Damage can cause sensory impairments, such as hemispatial neglect.
• Stimulation helps understand the lobe's functions.

Occipital Lobe

• Entirely devoted to processing visual information.
• Visual processing takes up a considerable amount of space in the human brain.
• Methods for understanding: damage (e.g., blows to the head, gunshot wounds) and electrical stimulation.

Temporal Lobe

• Involved in sensory processing.
  • Primary auditory cortex
  • Additional visual areas
• Medial temporal lobe: crucial for long-term memory, featuring the hippocampus (memory factory of the brain).

Medial Temporal Lobe

• Interior surface of the temporal lobe, containing an area called the medial temporal lobe (MTL).
• Hippocampus and other regions in the MTL play a crucial role in the formation of memories.

Medial Temporal Lobe (additional info)

• Hippocampus: essential for the formation of long-term memories.
• Amygdala: set of nuclei crucial for emotional processing and behaviors.

Introduction to Biopsychology (Fall 2024)

• Lecture 7C: Everything but the Cortex

Goals of This Section

• Explain the roles of the thalamus and hypothalamus
• Describe the three components of the brainstem
• Explore the sources of modulatory neurotransmitters in the brain
• Describe the organization and role of the cerebellum

Beneath the Cortex

• Corpus callosum: white matter tract connecting the two hemispheres.
• Thalamus (weeks 6-7): sensory relay to cortex
• Hypothalamus (unit 3): control of the autonomic and endocrine system.

Thalamus

• Located in the center of the brain, below the cortex.
• Two lobes, each connected by a white matter tract.
• Primary function: sensory relay to cortex.
• Organizes incoming sensory info and directs it.
• Divided into nuclei (e.g., LGN for vision).

Thalamus (additional info)

• Various thalamic nuclei act as "gatekeepers."
• Control the amount of information reaching the cortex.

Hypothalamus

• Located at the base of the brain, below the thalamus.
• Contains nuclei and tracts.
• Controls the autonomic and endocrine system.
• Organizes behavior related to survival (four Fs): fighting, fleeing, feeding, and mating.

Brainstem

• Composed of midbrain, pons, and medulla.
• Responsible for essential automatic functions and behaviors.
• Nuclei produce modulatory neurotransmitters (e.g., dopamine, serotonin, norepinephrine).

Brainstem: Midbrain

• Tectum ("roof"): dorsal part of the midbrain.
• Inferior colliculi: auditory system
• Superior colliculi: visual system (visual reflexes)
• Tegmentum ("floor").

Brainstem: Midbrain (additional info)

• Tegmentum: ventral part of midbrain.
• Substantia nigra (SN): movement
• Ventral tegmental area (VTA): motivational/reward
• Reticular formation (rostral end): nuclei produce other modulatory neurotransmitters.

Brainstem: Pons

• Bulge in brainstem.
• Reticular formation continues here.
• Involved in sleep, arousal, and relaying information.
• Locus coeruleus (norepinephrine) and raphe nuclei (serotonin).
• Relay nuclei (pontine nuclei), transmitting information between cortex and cerebellum.

Brainstem: Medulla

• Lowermost part of brainstem.
• Connects to spinal cord.
• Reticular formation containing more raphe nuclei.
• Regulates cardiovascular system, breathing, and skeletal muscle tone.
• Sensory systems making a stop here.

Neurotransmitters

• Dopamine: synthesized in ventral tegmental area and substantia nigra.
• Norepinephrine: synthesized in locus coeruleus.
• Serotonin: synthesized in raphe nuclei.

Cerebellum

• "Little cerebrum"
• Two hemispheres; densely packed with neurons (half of the brain's neurons).
• Critical for movement and timing.
• Involved in any movement that requires timing information (e.g., walking, playing the piano).