Deep layer prefrontal cortex unit discharge in a cue-controlled open-field environment in the freely-moving rat

The activity of single units in prefrontal cortex (prelimbic and anterior cingulate subregions) was recorded as rats performed a 'pellet-chasing' task in a cue-controlled, open-field environment in which the position of a single salient cue card was manipulated. Spike train analyses revealed three different types of unit. The first type was characterized by rhythmic bursts of spiking with inter-burst intervals of approximately 200 ms (66% of units), the second by bursts with inter-burst intervals of approximately 80 ms (33% of units), and the third by non-rhythmic firing characteristics (33% of units). None of the units had spatially-selective firing characteristics, nor were their discharge patterns affected by manipulation of the cue card. Instead, the firing of the units had multiple behavioural correlates that occurred as the rat explored the environment. These results are in line with previous studies that suggest that prefrontal cortex unit discharge is not related to spatial processing but to behaviours necessary for exploration.

[1]  Bruno Poucet,et al.  Effortful information processing in a spontaneous spatial situation by rats with medial prefrontal lesions , 1996, Behavioural Brain Research.

[2]  R. Muller,et al.  The effects of changes in the environment on the spatial firing of hippocampal complex-spike cells , 1987, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[3]  J. O’Keefe,et al.  Single unit activity in the rat hippocampus during a spatial memory task , 2004, Experimental Brain Research.

[4]  J. Pirch,et al.  Event-related slow potentials and activity of singly neurons in rat frontal cortex. , 1981, The International journal of neuroscience.

[5]  P. E. Sharp,et al.  Spatial correlates of firing patterns of single cells in the subiculum of the freely moving rat , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[6]  R. Passingham.  The frontal lobes and voluntary action , 1993 .

[7]  S. O’Mara.  Spatially selective firing properties of hippocampal formation neurons in rodents and primates , 1995, Progress in Neurobiology.

[8]  B. Poucet.  Spatial cognitive maps in animals: new hypotheses on their structure and neural mechanisms. , 1993, Psychological review.

[9]  Victor A. F. Lamme,et al.  Heterotopic Cortical Afferents to the Medial Prefrontal Cortex in the Rat. A Combined Retrograde and Anterograde Tracer Study , 1992, The European journal of neuroscience.

[10]  Bruno Poucet,et al.  Searching for spatial unit firing in the prelimbic area of the rat medial prefrontal cortex , 1997, Behavioural Brain Research.

[11]  T. Jay,et al.  NMDA Receptor‐dependent Long‐term Potentiation in the Hippocampal Afferent Fibre System to the Prefrontal Cortex in the Rat , 1995, The European journal of neuroscience.

[12]  J. Glowinski,et al.  Anatomical and electrophysiological evidence for a direct projection from ammon's horn to the medial prefrontal cortex in the rat , 2004, Experimental Brain Research.

[13]  B Poucet,et al.  The neuropsychology of spatial cognition in the rat. , 1997, Critical reviews in neurobiology.

[14]  S M O'Mara,et al.  Medial prefrontal cortex lesions cause deficits in a variable-goal location task but not in object exploration. , 1999, Behavioral neuroscience.

[15]  B. McNaughton,et al.  Firing characteristics of deep layer neurons in prefrontal cortex in rats performing spatial working memory tasks. , 1998, Cerebral cortex.

[16]  G. Paxinos,et al.  The Rat Brain in Stereotaxic Coordinates , 1983 .

[17]  G. Rigdon,et al.  Microinjection of procaine or GABA into the nucleus basalis magnocellularis affects cue-elicited unit responses in the rat frontal cortex , 1984, Experimental Neurology.

[18]  J. Seamans,et al.  Electrophysiological and morphological properties of layers V-VI principal pyramidal cells in rat prefrontal cortex in vitro , 1996, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[19]  B Poucet,et al.  Medial prefrontal lesions in the rat and spatial navigation: evidence for impaired planning. , 1995, Behavioral neuroscience.

[20]  B. Connors,et al.  Intrinsic firing patterns of diverse neocortical neurons , 1990, Trends in Neurosciences.

[21]  B. Poucet.  Object exploration, habituation, and response to a spatial change in rats following septal or medial frontal cortical damage. , 1989, Behavioral neuroscience.

[22]  Y. Sakurai,et al.  Multiple unit activity of prefrontal cortex and dorsomedial thalamus during delayed go/no-go alternation in the rat , 1986, Behavioural Brain Research.

[23]  L. Nadel,et al.  The Hippocampus as a Cognitive Map , 1978 .

[24]  G. Snyder,et al.  A comparison of the electrophysiological properties of morphologically identified cells in layers 5B and 6 of the rat neocortex , 1992, Neuroscience.

[25]  S. O’Mara,et al.  The subiculum: a review of form, physiology and function , 2001, Progress in Neurobiology.

[26]  G. Rigdon,et al.  Single-unit and slow potential responses from rat frontal cortex during associative conditioning , 1983, Experimental Neurology.

[27]  L. Swanson,et al.  A direct projection from Ammon's horn to prefrontal cortex in the rat , 1981, Brain Research.

[28]  J. O’Keefe,et al.  Hippocampal Complex Spike Cells do not Change Their Place Fields if the Goal is Moved Within a Cue Controlled Environment , 1990, The European journal of neuroscience.

[29]  J. Fuster.  The Prefrontal Cortex , 1997 .

[30]  B. Kolb,et al.  The Cerebral cortex of the rat , 1990 .

[31]  J. O’Keefe.  A review of the hippocampal place cells , 1979, Progress in Neurobiology.