Hypothalamus/ ANS and Limbic system/Temporal Lobe

• The hypothalamus is the interface of the nervous system and the endocrine system
• Functions of the hypothalamus

  • Regulating blood pressure and electrolyte composition
  • Regulating energy metabolism
  • Regulating reproductive behaviours
  • Regulating body temperature
  • Regulating defensive behaviour
  • Regulating sleep-wake behaviour
• Hypothalamus neurons release


  • Oxytocin and vasopressin in posterior pituitary (neuro)
  • Growth hormone-releasing hormone and gonadotropin-releasing hormone to anterior pituitary (endocrine)
• Major hypothalamus nuclei

  • Supraoptic
  • Arcuate nucleus
  • Paraventricular
  • Mammillary body
  • Suprachiasmatic
  • Ventromedial hypothalamic
• Supraoptic nucleus

  Produces vasopressin (uterine contraction and lactation)
• Arcuate nucleus


  Involved in feeding, metabolism, fertility, and cardiovascular regulation
• Paraventricular nucleus


  Synthesises oxytocin (vasoconstriction, water resorption in kidneys)
• Mammillary body


  Involved in recollective memory
• Suprachiasmatic nucleus


  Involved in sleep/waking cycle
• Ventromedial hypothalamic nucleus


  Involved in control of food and fluid intake
• Anterior pituitary


  Of endocrine origin
• Posterior pituitary


  Of neuro origin
• Hypothalamus neurons release peptide hormones, such as oxytocin and vasopressin, in posterior pituitary which are transported to the secreting cells in anterior pituitary
• Growth hormone-releasing hormone (GHRH)

  Acts to release growth hormone (GH)
• Gonadotropin-releasing hormone (GnRH)

  Acts to release follicle-stimulating hormone (FSH)
• Autonomic system

  Consists of sympathetic and parasympathetic division
• Principal function of the autonomic system

  Homeostasis of the internal environment
• Autonomic behaviors are linked to emotional arousal, stress, motivation and defensive reactions
• Autonomic motor system

  • Innervates and regulates gland cells, smooth and cardiac muscle
  • Maintains body temperature
  • Controls eating, drinking and sexual behavior
  • Although largely involuntary it is tightly integrated with voluntary movements
• Baroreceptors

  Sense arterial blood pressure in the carotid sinus
• Baroreceptor feedback

  Provides feedback control of the cardiovascular system
• Sympathetic components

  Stimulate the heart increasing cardiac output and cause arteries to contract, increasing mean arterial blood pressure
• The ventral view of the cerebrum has the orbital, straight, parahippocampal, fusiform gyri
• Structures of the limbic system

  • Cingulate gyrus
  • Parahippocampal gyrus
  • Hippocampus
  • Amygdala
  • Fornix
  • Olfactory system
• Cingulate gyrus


  Involved in emotions and behaviour
• Parahippocampal gyrus

  Involved in memory encoding and retrieval
• Hippocampus


  Involved in converting short-term memory to long-term memory and in spatial memory
• Amygdala


  Involved in memory, decision making, and emotional responses
• Fornix


  Major output fiber tract of the hippocampus
• Olfactory system


  Involved in smell
• Functional areas of the temporal lobe

  • Entorhinal cortex
  • Perirhinal cortex
  • Parahippocampal cortex
  • Parahippocampal place area
  • Fusiform gyrus
• Entorhinal cortex


  Involved in declarative & spatial memories including memory formation, memory consolidation, and memory optimization in sleep
• Perirhinal cortex


  Involved in visual recognition memory, item memory, coding familiarity or recency of items
• Parahippocampal cortex


  Involved in memory encoding and retrieval
• Parahippocampal place area


  Encodes environmental scenes
• Fusiform gyrus


  Involved in processing of color information, fusiform face area, synaesthesia, and prosopagnosia
• Hippocampus

  Major role in the consolidation of information from short-term memory to long-term memory, and in spatial memory
• Subdivisions of the hippocampus

  • Hippocampus proper: CA1, CA2, CA3, CA4
  • Dentate gyrus
• Amnesia: HM = bilateral surgery for seizures, intact working memory, long-term memory for events before surgery, name, childhood, language, IQ, couldn't create new memories (anterograde amnesia)
• Horizontal sections show the corpus callosum, caudate nucleus, insula, septum pellucidum, internal capsule, external capsule, putamen, lateral ventricles, third ventricle