CorpusHuman Anatomy
NervousBrain region

Limbic lobe

Lobus limbicus

Also known as: cingulate and parahippocampal gyri, great limbic lobe of Broca

The C-shaped ring of cortex on the medial surface of each hemisphere that borders the corpus callosum and diencephalon, made up mainly of the cingulate and parahippocampal gyri, and the cortical core of the limbic system.

Show on body map Brain — Midsagittal Section

Overview

Broca (1878) named this ring the grand lobe limbique because it forms a border (limbus) around the hemisphere's hilum. It consists of three parts:
• the cingulate gyrus, arching above the corpus callosum within the cingulate sulcus;
• the narrow isthmus, behind the splenium;
• the parahippocampal gyrus on the inferomedial temporal lobe, whose anterior end hooks round as the uncus.
The subcallosal (septal) area beneath the rostrum completes the ring in front. A bundle of association fibres, the cingulum, runs within the ring and links its parts.

The anterior cingulate cortex monitors conflict and errors, drives motivated behaviour, contributes to the unpleasantness of pain and regulates autonomic responses. The posterior cingulate and adjacent precuneus are hubs of the default mode network and support memory retrieval. The anterior parahippocampal gyrus contains the entorhinal cortex (area 28), the main gateway between the neocortex and the hippocampus. Its grid cells encode spatial location, and it is the first cortical region to develop neurofibrillary tangles in Alzheimer disease.

Location

Medial surface of each hemisphere, encircling the corpus callosum (cingulate gyrus) and continuing onto the inferomedial temporal lobe (parahippocampal gyrus).

Parts & subdivisions

  1. Cingulate gyrus
    Anterior: emotion, motivation, pain affect, error monitoring, autonomic control. Posterior: memory, self-referential thought (default mode network).
  2. Isthmus of the cingulate gyrus
    Narrow link behind the splenium joining the cingulate and parahippocampal gyri.
  3. Parahippocampal gyrus
    Entorhinal cortex anteriorly (gateway to the hippocampus); parahippocampal place area posteriorly (scene recognition).
  4. Uncus
    Hooked anterior end of the parahippocampal gyrus overlying the amygdala; part of the primary olfactory cortex; clinically important in transtentorial herniation.
  5. Cingulum
    Association bundle within the cingulate and parahippocampal gyri; part of the Papez circuit.

Anatomy

Arterial supply

Anterior cerebral artery (pericallosal and callosomarginal branches) for the cingulate gyrus; posterior cerebral artery for the parahippocampal gyrus; anterior choroidal artery for the uncus.

Function

  • Emotional and motivational processing
  • Affective (unpleasant) component of pain
  • Gateway of neocortical information to the hippocampus for memory
  • Spatial navigation (entorhinal grid cells)
  • Error detection and cognitive control

Clinical significance

Akinetic mutism

Bilateral damage to the anterior cingulate and medial frontal cortex, e.g. from bilateral ACA infarction after an ACom aneurysm or from a tumour, leaves the patient awake but without spontaneous speech or movement. This is profound abulia.

Entorhinal cortex in Alzheimer disease

Neurofibrillary tangles appear first in the transentorhinal and entorhinal cortex (Braak stages I–II). This disconnects the hippocampus from the neocortex and explains why episodic memory fails early.

Compiled from standard anatomy and physiology references — see the Nervous System sources. For education only; not medical advice.