The thalamic reticular nucleus and schizophrenia.
BACKGROUND
The thalamic reticular nucleus (TRN) is a shell-shaped gamma amino butyric acid (GABA)ergic nucleus, which is uniquely placed between the thalamus and the cortex, because it receives excitatory afferents from both cortical and thalamic neurons and sends inhibitory projections to all nuclei of the dorsal thalamus.


METHODS
A review of the evidence suggesting that the TRN is implicated in the neurobiology of schizophrenia.


RESULTS
TRN-thalamus circuits are implicated in bottom-up as well as top-down processing. TRN projections to nonspecific nuclei of the dorsal thalamus mediate top-down processes, including attentional modulation, which are initiated by cortical afferents to the TRN. TRN-thalamus circuits are also involved in bottom-up activities, including sensory gating and the transfer to the cortex of sleep spindles. Intriguingly, deficits in attention and sensory gating have been consistently found in schizophrenics, including first-break and chronic patients. Furthermore, high-density electroencephalographic studies have revealed a marked reduction in sleep spindles in schizophrenics.


CONCLUSIONS
On the basis of our current knowledge on the molecular and anatomo-functional properties of the TRN, we suggest that this thalamic GABAergic nucleus may be involved in the neurobiology of schizophrenia.
Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin at Madison, Madison, WI 53719, USA.
Fabio
F
Ferrarelli
Giulio
G
Tononi
D000344:Afferent Pathways / Q000503:physiopathology; D000818:Animals; D001288:Attention / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D004569:Electroencephalography; D006801:Humans; D009415:Nerve Net / Q000503:physiopathology*; D018079:Receptors, GABA / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D055139:Sensory Gating / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D012894:Sleep Stages / Q000502:physiology; D013787:Thalamic Nuclei / Q000503:physiopathology*
D018079:Receptors, GABA