 gonadotropic hormone)
- Descending tracts to brain stem to regulate autonomic centres related to cardiovascular and breathing functions
- Integrating emotions and autonomic responses
- Link to centre for “set points” relating to appetite, body temperature -
Biological clock and circadian rhythms
- Link to limbic system
Forebrain - Limbic System (in Telencephalo)
subcallosal gyrus (anterior and inferior continuation of the cingulate gyrus)
Hippocampal formation (hippocampus, dentate gyrus and subiculum)
Amygdala has two important projections to hypothalamus and dorso-medial thalamic nuclei and it receives an important afferent input from the olfactory tract
Emotional processing (e.g. fear) and social behaviour
Bilateral damage of amygdala results in Klüver-Bucy syndrome
CT and MRI neuroimaging
How the brain looks like?
Computed tomography (CT).
Various attenuation intensity of x-rays according to type of tissue. This is computerised into numbers.
Positive numbers (+1,000) are represented white (e.g. bone), negative numbers (-1,000) are represented black (e.g. air)
The brain and related structures in CT
Structure/fluid/space - grey scale
Bone/acute blood - very white
Grey matter - light grey
White matter - medium grey
Cerebrospinal fluid - dark grey to black
Subacute blood - light grey
CT and MRI: MRI
Structure/fluid/space T1 T2
Bone - very black - very black
Air - very black - very black
Grey matter - dark grey - light grey
White matter - light grey - dark grey
Cerebrospinal fluid - very black - very white
Edema - Dark grey - light grey to white
CT and MRI: Advantages
Advantages of CT scan:
- Clearly shows acute and subacute hemorrhages into the meningeal spaces and brain
-Better in showing bone and bone fractures
-Rapid (important for emergency) and cheap
-Advantages of MRI scan:
-Excellent spatial resolution. It better differentiates white and grey matter than CT Scan.
-It clearly shows acute or subacute infarcts or ischemia or brain edema
-No radiation exposition and, at the present, not known harmful effects
A sagittal MRI of a 23-year-old woman is located at, or immediately adjacent to, the midline. Which of the following spaces or structures would be in the image and would indicate a midline plane?
a) Cerebral aqueduct
c) Interventricular fossa