The document details the limbic system, a complex ring of cortical and subcortical structures essential for emotional processing and memory, highlighting its connection to the olfactory lobe. It also discusses the role of the piriform cortex and its relationship with other brain areas, including how compensatory changes enable odor perception during sensory deprivation. Additionally, various clinical syndromes associated with hypo and hyperactivity of the limbic system, such as depression and mania, are outlined.

1. -By Dr. Rima Jani PT
(B.P.T., M.P.T. Pediatric Science)

3.  Limbus means ring. It is also known as limbic lobe. Earlier, it was
called rhinencephalon.
 Limbic system is a complex system of cortical and subcortical
structures that form a ring around the hilus of cerebral hemisphere.
 Limbic system is one of the oldest parts of the brain and it is
related to olfactory lobe.
 Limbic system is primarily related to emotional part of our life and is
extensively concerned with memory.
Introduction

24.  The piriform cortex is the largest cortical
recipient of direct olfactory bulb
projections.
 The relationship between the piriform
cortex and the orbitofrontal cortex is
similarly complex.
 The entorhinal cortex, typically seen as
the gateway into the hippocampus, also
sends a strong projection back to the
piriform cortex, and modulates fine odor
discrimination.
PIRIFORM CORTEX

25.  Compensatory changes in
brain regions, including the
piriform cortex and
Orbitofrontal Cortex (OFC),
may allow the olfactory
system to experience
prolonged periods of
deprivation without marked
changes in odor perception.

26. 1. Fornix: It includes fibers connecting:
 Hippocampus and septal nuclei with the mamillary body
 Hippocampus with hypothalamic nuclei.
2. Lateral hypothalamus receives afferent fibers from:
 Hippocampus
 Septal nuclei
 Olfactory tubercle
 Head of caudate nucleus
 Piriform area
 Periamygdaloid area.
CONNECTIONS OF LIMBIC SYSTEM

27. 3. Caudate nucleus receives fibers from:
 Cingulate gyrus
 Intralaminar nuclei of thalamus.
4. Brainstem reticular formation receives fibers from:
 Hippocampus
 Cingulate gyrus.
5. Papez circuit.
CONNECTIONS OF LIMBIC SYSTEM

32. Clinical Syndromes
Hypo limbic
 Depression
 Apathy
 Utilization behaviour
 Amnesia (hippocampus)
 Social Dysdecorum
 Kluver-Bucy Syndrome
(Amygdala)
 Anxiety/Panic
 Psychosis
Limbic Epilepsy
Limbic encephalitis
Rage (Hypothalamus & Amygdala)
Hyper limbic
 Mania
 OCD