Lecture 2_Biological influences on behaviour-2

Biological psychology is the study of physiological, evolutionary, and developmental mechanisms of behavior and experience.

There are approximately 12-15 billion neurons in the cerebral cortex, 1 billion neurons in the spinal cord, and 70 billion neurons in the cerebellum.

The primary function of neurons is to receive information and transmit it to other cells. The axon transfers nerve impulses from the soma, dendrites transfer nerve impulses to the soma, and presynaptic terminals release neurotransmitters to communicate with other neurons.

The cell membrane protects and holds the cell content while allowing for chemical transfer.

The three major types of neurons are sensory neurons, which respond to specific types of stimulation; motor neurons, which conduct impulses from the soma to muscle or gland cells; and interneurons, which facilitate communication between sensory and motor neurons by forming circuits.

The sensory nerves relay the sensory information toward the central nervous system, and the motor output from the central nervous system allows the person to lift the glass to take the drink.

An action potential is triggered when the neuron is stimulated or excited, and the state of a neuron when it is not excited is called resting potential.

Chemical events take place, where neurotransmitters are released from one neuron to another, affecting the second neuron and potentially exciting it to fire an action potential.

The two main components of the CNS are the brain and spinal cord, while the PNS consists of nerves outside the brain and spinal cord.

The nervous system controls motor functions of voluntary and involuntary muscles, and the spinal cord is responsible for some reflexes, such as the knee-jerk reflex.

The autonomic nervous system receives information from and sends commands to the heart, intestines, and other organs. The sympathetic nervous system prepares the body for vigorous activities, while the parasympathetic nervous system promotes energy-conserving functions.

The midbrain plays a role in vision, hearing, and motor control; the medulla controls autonomic functions such as breathing and heart rate; the cerebellum coordinates voluntary movements and balance; and the thalamus acts as a relay station for sensory information.

The limbic system is associated with motivation, emotion, drives, and aggression, and its main components include the hippocampus and amygdala, which are involved in memory and emotional processing.

The hippocampus consolidates short-term memory into long-term memory and plays a role in navigation, while the amygdala is involved in feelings and expressions of emotions, especially fear.

The forebrain includes the cerebral cortex, which is responsible for higher brain functions, and the corpus callosum, which connects the left and right hemispheres.

The four lobes of the brain are the Occipital lobe (vision), Frontal lobe (higher cognitive functions), Parietal lobe (sensory information processing), and Temporal lobe (auditory processing and language comprehension).

The prefrontal cortex is responsible for higher-order activities such as logical thinking and planning, and damage to it can lead to memory failure and difficulties in understanding emotions.

Behavior genetics is the study of how genes and environmental factors influence behavior, with a bidirectional relationship where environmental influences can impact genetics.

Genotype refers to the genetic material inherited by an individual, while phenotype refers to the expressed genetic material, including observable behavior and physical characteristics, which depend on the interaction of genotype and environment.