PS11220 Lecture Notes: Brain Behavior & Cognition - Lecture 1

Lecture 1: Brain Structure and Function (Part 1)

Delivered by: Dr. Eva Balgova
evb14@aber.ac.uk
Office Hours: Monday 11:00-12:30, Friday 14:00-15:30, P5, room 1.31

Key Points (Lecture 0)

• Online Lecture: If you haven't watched the online lecture, do so as soon as possible.

• Module Information: Contains information about structure, schedule, and assessment.

• Blackboard Access: Essential for module resources.

• Discussion Boards: Use for questions, contact staff via email or in person.

Divisions of the Nervous System (Part 1)

• Central Nervous System (CNS): Includes the brain and spinal cord.

• Peripheral Nervous System (PNS): Comprises all parts of the nervous system outside the CNS.

Components of the PNS

• Somatic System: Links spinal cord with body and sense organs; responsible for voluntary behavior.

• Autonomic System: Serves internal organs and glands, governing automatic (involuntary) functions.

Autonomic Nervous System

Divisions

1. Sympathetic: Activation during emergencies; "fight or flight" response.

   • Arouses the body, stimulates, organizes, and mobilizes energy resources; expends energy.

2. Parasympathetic: Relaxation response; "rest and digest."

   • Conserves energy, active post-emotional events.

Sympathetic Response: Fight or Flight

Physical Indicators

• Dilated pupils

• Trembling

• Pale or flushed skin

• Rapid heartbeat and breathing

Mechanism of Action

1. Neurotransmitter Release: Acetylcholine released in the autonomic nervous system.

2. Activation: Stimulates adrenal medulla to release:

   • Epinephrine (Adrenalin): Increases glucose metabolism and energy supply to muscles.

   • Norepinephrine (Noradrenalin): Increases heart rate and blood pressure.

3. Interaction with HPA Axis: Coordinates the hormonal component of the stress response.

Somatic Nervous System

• Function: Enables sensory input and movement control; connects CNS with skin, sensory organs, and skeletal muscles.

• Role: Involved in voluntary movements and reflexes.

Reflexes in the Somatic System

1. Sensory receptor detects a stimulus.

2. Sensory neuron transmits signals to the PNS via afferent nerve fibers.

3. Integration center in the spinal cord decodes the signal.

4. Signal travels via efferent nerve fibers to effectors (muscles).

5. Effector muscle cells contract as a response.

Comparison: Autonomic vs. Somatic Nervous System

Autonomic Nervous System

• Involuntary: Manages internal organ functions (heart, lungs, etc.).

• Automatic Responses: Unconscious control (e.g., heart rate changes).

Somatic Nervous System

• Voluntary: Controls voluntary movements (e.g., skeletal muscles).

• Under conscious control for actions like walking or writing.

The Central Nervous System: Spinal Cord

Functions of the Spinal Cord

1. Conduit for motor information: Sends signals from CNS to effector organs.

2. Conduit for sensory information: Receives signals from sensory receptors.

3. Coordination of reflexes: Basic reflex center.

Anatomy of the Spinal Cord

• Grey matter: Inner layer, mainly nerve cell bodies.

• White matter: Outer layer, myelinated axons.

• Dorsal horn: Entry point for afferent nerve fibers.

• Ventral horn: Exit point for efferent nerve fibers.

Neurological Terms and References

Directional Terms

• Lateral: Toward the side, away from the middle.

• Medial: Toward the middle, away from the side.

• Ipsilateral: Same side.

• Contralateral: Opposite side.

Specific Anatomical Directions

• Anterior/Rostral: Toward face/front of the brain (top of spinal cord).

• Posterior/Caudal: Toward back of brain/bottom of spinal cord.

• Superior/Dorsal: Toward top of head/top of brain; back of spinal cord.

• Inferior/Ventral: Toward feet/bottom of brain; front of spinal cord.

Planes of Section in Brain Anatomy

• Coronal Plane: Frontal section.

• Horizontal Plane: Cross-section.

• Sagittal Plane: Divides left and right.

Summary of Part 1

• The nervous system has various subdivisions.

• The autonomic nervous system regulates involuntary processes, while the somatic system involves conscious control.

• Reflexes are basic neural responses; the peripheral NS connects to the CNS via the spinal cord.

• The spinal cord serves as a conduit for sensory-motor information and as a hub for basic reflexes.

• Anatomical locations within the nervous system can be precisely referenced.