Psychology: The Limbic System Overview

These fibers connect the hypothalamus to the brainstem and spinal cord, regulating autonomic functions like heart rate, blood pressure, and digestion.

These fibers connect the hypothalamus to the anterior nucleus of the thalamus, involved in memory and emotional processing.

These fibers connect the hypothalamus to the reticular formation in the midbrain, involved in controlling alertness and sleep-wake cycles.

Damage to this area results in hyperthermia (high body temperature).

Damage to this area results in hypophagia (reduced eating).

The sense of smell is closely linked to memories, emotions and moods. This explains why we often remember scents vividly.

The sense of smell plays a significant role in how we communicate with each other, as demonstrated by the perfume industry.

Odorant receptors in the olfactory epithelium are responsible for detecting different scents.

Groups of neurons with the same type of receptor project to the same glomerulus in the olfactory bulb.

Mitral and tufted cells are the main output neurons from the olfactory bulb, carrying signal further for processing.

Periglomerular cells and granule cells are inhibitory neurons, regulating the activity of other neurons in the olfactory bulb.

Olfactory receptor neurons are bipolar cells, with one end containing odorant receptors and the other sending signals to the olfactory bulb.

The olfactory system processes smell information through a series of steps, starting with the binding of odorants to receptors and ending with the perception of smell in the brain.

A group of brain structures involved in processing emotions, learning, and memory. It includes the hippocampus, amygdala, hypothalamus, and cingulate cortex.

A closed-loop neural circuit that plays a key role in memory and emotion. It includes the hippocampus, hypothalamus, thalamus, and cingulate cortex.

The part of the brain responsible for regulating bodily functions like hunger, thirst, body temperature, and sleep-wake cycles.

A brain structure involved in processing and storing memories, particularly long-term memories.

A brain structure situated in the temporal lobe, responsible for processing emotions, especially fear and anxiety.

The process of forming new neurons in the brain, particularly in the olfactory bulb and hippocampus.

A brain structure involved in processing olfactory signals and connecting them to the limbic system, influencing emotional responses to smells.

A part of the limbic system that plays a role in emotional processing, especially related to fear and anxiety.

The anterior, middle, and posterior regions of the hypothalamus each have specific functions.

A crucial part of the hypothalamus involved in memory and learning, particularly spatial memory.

The process by which the hypothalamus, pituitary gland, and adrenal glands work together to regulate stress responses.

A collection of nuclei in the hypothalamus that control vital autonomic functions, including breathing, heart rate, and digestion.

A long neural pathway connecting the cingulate cortex to the allocortex, facilitating communication between these brain regions.

Information from the frontal lobe of the cerebral cortex directly arrives at the hypothalamus through these fibers.

Neural signals transmitted from the hippocampus to the mammillary body through the fornix, crucial for memory and spatial navigation.

Inhibitory neurons in the nervous system use GABA, Dopamine or Glycine as their neurotransmitters.

The axons of olfactory neurons terminate in a specialized layer of the olfactory bulb called the glomerular layer.

The olfactory system in humans is simpler compared to other animals. We lack a vomeronasal organ, which is responsible for detecting pheromones.

The primary olfactory cortex is the first area in the brain that receives olfactory information. It is located in the uncus, a bump on the brain's surface.

The olfactory bulb connects to the other side of the brain through the anterior commissure, sending signals to the subthalamic nuclei and hypothalamus eventually reaching the amygdala and parahippocampal gyrus.

Humans can detect thousands of smells, but smell is largely an aesthetic sense. In contrast, animals rely heavily on smell for survival, using it to find food, mates, and avoid danger.

The basolateral amygdala is a key region involved in learning and memory, particularly for fear and emotional responses. It receives sensory input from various cortical areas and influences the processing of sensory information. It also plays a pivotal role in regulating emotional responses and behavior through connections with the thalamus, striatum, and neocortex.

The olfactory amygdala plays a crucial role in processing olfactory (smell) information. It receives input from both the olfactory bulb and the olfactory cortex, allowing it to analyze and interpret smells. It is especially important in animals for identifying pheromones. This region also projects to the centromedial amygdala and the hypothalamus, which are involved in regulating emotional and physiological responses.

The centromedial amygdala serves as a crucial link between the amygdala and the hypothalamus, which is responsible for regulating many bodily functions, including hormones and autonomic responses. It receives projections from the basolateral, olfactory amygdala, and cortical regions, integrating various sensory and emotional information. It is involved in fear responses, autonomic activation, and the expression of emotional behavior.

The extended amygdala is a network of interconnected brain structures that extends beyond the traditional boundaries of the amygdala. It includes the bed nucleus of stria terminalis (BST) and the basal nucleus of Meynert. This area plays an important role in regulating stress responses, anxiety, and addiction-related behaviors. It is also linked to social and emotional processing.

The fornix is a bundle of nerve fibers that forms a crucial connection between the hippocampus and the hypothalamus, two vital brain structures. It allows for communication and information transfer between these areas, facilitating memory and emotional processing, and overall cognitive function.

Hippocampus is formed during the convolution of the cortex in the temporal lobe. It is allocated to the allocortex, a type of cerebral cortex with a simpler structure compared to neocortex (with fewer neuronal layers). Lower-order mammals tend to have larger hippocampi, indicating its potential role in spatial navigation and memory.

The tri-synaptic circuit of the hippocampus is a fundamental neural pathway within the hippocampus that is essential for memory formation and information processing. It involves three key synapses or connections, which are crucial for transferring information between different neuronal populations within the hippocampus. This neural circuit underpins spatial learning and memory, and impairments can affect spatial navigation and other aspects of cognitive function.