Lecture 3- The Cingulate Cortex Flashcards
The cingulate cortex location
Lies directly above corpus callosum on medial wall of each hemisphere
Separated from neocortex by cingulate sulcus
Positioning of cingulate cortex
Posteriorly: continues into precuneus via isthmus to join parahippocampal gyrus
Anteriorly: merges with cortex around genu of corpus callosum and continues forward as the subgenual cortex adjacent to septum
Division of cingulate gyrus
Prelimibic (32)
Infralimbic cortices (25)
Anterior cingulate cortex (23 + 24)
Part of posterior cingulate or retrosplenial cortex (29)
Prelimic and infralimbic part
Contain specific motor areas
Have extensive connections with neocortical areas of frontal lobe
Anterior cingulate cortex
Has equally extensive connections with somatosensory and visual-association areas of parietal, occipital and temporal lobes
Afferents of cingulate gyrus
Predominantly from neocortical areas on lateral surface of the hemispheres
Most projections pass caudally, into the posterior parahippocampal gyrus
Parahippocampal gyrus
Areas 27, 28, 35, 36, 48, 49 and temporal cortical fields
Has complex interconnections with the cingulate cortex and with hippocampal formation
Motor regions of cingulate cortex and facial expressions
Direct projections from cingulate motor cortex to CN 7 (facial) nulceus in brainstem
Produces the emotional content of facial expression
Vocalisations in animals and humans
Cingulate cortex initiates involuntary vocalisations (ow)
Cingulate and amygdala provide emotional intonation in language
6 functional areas associated with anterior cingulate cortex
Autonomic Bladder control Emotional Executive Nociceptive (pain perception) Vocalization
Executive area
Execution of willed movement and voluntary saccades
Generate appropriate motor plan selection by motor cortex
Pain perception
Afferents from MDN of thalamus
Emotional
Lights up in happy thoughts; amygdala switches off (reverse is also true)
Bladder control
Active during bladder filling
Vocalisation
Active with the dorsal prefrontal cortex during decision making about appropriate sentence structure for speech
Stammering implicated in reduced blood flow to ACC
Autonomic
Elicits autonomic and respiratory responses especially in emotional state
Posterior cingulate cortex
Merges with the posterior parahippocampal gyrus
Interconnected with visual, auditory and tactile/spatial association areas
Involved in memory functions associated with the above
Lesions of cingulate cortex
Of anterior
- Inability to restrain response to negatives
Disruption of orderly behaviours
Inability to anticipate emotional consequences of behaviour for both rewards and punishments
Olfactory system
Afferent olfactory pathways proceed directly to the cerebral cortex, bypassing the thalamus, terminal fields are primitive cortical areas that are considered to be parts of the limbic system
Not a limbic structure but projects heavily upon limbic structures
Patterns of neural connectivity in the olfactory system
Strong projection to the amygdala
Decussation of fibres to the opposite bulb
Direct projection to olfactory (piriform) cortex (amygdala, uncus and parahippocampus)
What is special about the olfactory system?
The input reaches the cortex without passing through the dorsal thalamus
Direct input to the amygdala, therefore odours are strongly associated with emotional states
No direct connection with other cortical areas, must pass through many stations before reaching neocortex
Damage to one side associated with ipsilateral anosmia
