Hypothalamus/Limbic System

Emotion

short term subjective experience

Drive

primitive survival urge

Limbic System form structural border

Between Diencephalon and the Neocortex

5 primary structures of limbic system

Hypothalamus-Homeostasis, Olfactory Structures-Olfaction, Hippocampus-Memory, Amygdala-Emotion, Limbic lobe-Executive function

Structural Components of Hypothalamus

Hypothalamic nuclei (different functions), Mammillary bodies (memory), Infundibular stalk/Infundibulum (connects hypothalamus to pituitary gland

Primary function of Hypothalamus

Master controller of homeostasis

Hypothalamus effect on Endocrine System

via the infundibulum or infundibular stalk links the nervous system to endocrine system

Pituitary Gland lobes

Anterior (releases hormones) & Posterior (extension of the hypothalamus)

Hypothalamus effect on Autonomic Nervous System

Major control center of the autonomic nervous system

Hypothalamus effect on Autonomic Nervous System (Sympathetic)

Fight, Flight or Freeze, preganglionic nerves originate in throacolumbar region

Hypothalamus effect on Autonomic Nervous System (Parasympathetic)

Conservation and restoration, preganglionic nerves originate in craniosacral region of BS/SC

Damage to Hypothalamus

Disrupt body’s homeostasis, can affect change sin levels of activity, passivity vs rage

Olfactory Pathway

Olfactory bulbs→ olfactory tracts→ primary olfactory cortex

Olfactory primary function

Olfaction

Proust effect

memory triggered by smell

Damage to Olfactory

Anosmia

Limbic Lobe/Cortex

found only on medial aspect of each hemisphere, encircles the corpus callosum + diencephalon

Limbic Lobe/Cortex (Cingulate Gyrus)

Process emotions, motivations, and behaviors

Limbic Lobe/Cortex (Parahippocampal gyrus)

Involved in memory

Define a lobe

a region of cortex similar anatomy or function

Define a system

Array of structures, cortex and other structures, that have similar function

Hippocampus Location

submerged deep into the parahippocampus gyrus, lies in limbic lobe

Primary Function of Hippocampus

involved in declarative (explicit) memory and converts short term memory to long term memory

Primary Input to the hippocampus (Entorhinal cortex)

Primary olfactory cortex (olfaction), Anterior/Posterior multimodal association areas (sensory perceptual), septal area and amygdala (pleasure and anger), Cingulate gyrus (emotional state), Orbitofrontal cortex (decisions about emotions)

Septal Area

Gray matter anterior to the anterior commissure, thought to be a self-reward center, runners high

Primary Outputs of the Hippocampus

Entorhinal cortex, Fornix (white matter pathway)

Damage to Hippocampus

Anterograde memory loss

Amygdala

Almond-shaped collection of about a dozen nuclei

Location of Amygdala

Medial temporal pole just anterior to the hippocampus

Primary Function of Amygdala

Source of raw emotion, links the perception of objects and situations with appropriate emotional responses

Primary Inputs to the Amygdala

Familiar 5 senses/visceral senses (primary sensory cortex+thalamus, Physiological state (hypothalamus), Emotional state (limbic cortex)

Primary Outputs of the Amygdala

Cortex (prefrontal, limbic, sensory), Basal nuclei, hypothalamus and brainstem

Damage to Amygdala

Lead to overeating (bulimia), undereating (anorexia), social phobia, addiction, and hypersexuality, often fear, people with autism may have more volume in amygdala, Bilateral lesions impair emotional good or bad